Conservative Management and
Neurodevelopment in patients with Congenital
Hyperinsulinism
A Thesis Submitted To The University Of Manchester
For The Degree Of Master of Philosophy
In The Faculty Of Biology, Medicine And Health
2019
María A. Salomón Estébanez
THE SCHOOL OF MEDICAL SCIENCES
LIST OF CONTENTS
LIST OF FIGURES ……………………………………………………………………………….. 4
LIST OF TABLES ………………………………………………………………………………… 5
ABSTRACT ………………………………………………………………….……………………. 6
DECLARATIONS AND COPYRIGHT STATEMENT...... 7
Declaration and copyright statement ...... 7
Thesis in Journal Format ………………………………………………..……………… 8
Publications and presentations generated from this thesis ……..……..…………… 9
Research projects and funding generated from this thesis …………………………. 11
ACKNOWLEDGEMENTS ..……………………………………………………………………… 12
CHAPTER 1. INTRODUCTION …………………………………………..…………………….. 13
1.1 Congenital Hyperinsulinism (CHI) ……………………………….………………... 13
1.2 Aetiology ………………………………………………………………..…………… 13
1.3 Histological forms of CHI …………………………………………….…………….. 15
1.4 Diagnosis and initial management ………………………..………………………. 16
1.5 Medical treatment ……………………………………………………….………….. 18
1.6 Outcomes of CHI …………………………………………………………………… 21
1.6.1 Natural history of the disease ………………..………………………….. 21
1.6.2 Neurodevelopmental outcomes ………….……………………………… 22
1.7 References …………..……………………………………………………………… 23
CHAPTER 2. PROJECT AIMS AND OBJECTIVES .…..……………………………...…... 27
CHAPTER 3. Conservatively treated Congenital Hyperinsulinism (CHI) due to KATP channel gene mutations: reducing severity over time ..…………………………………. 30
3.1 Abstract ………………………………………………………………………………. 31
3.2 Background ………………………………………………………………………….. 32
3.3 Aims ………………………………………………………………………………….. 33
3.4 Methods ……………………………………………………………………………… 33
3.5 Results ……………………………………………………………………………….. 36
3.6 Discussion …………………………………………………………………………… 48
3.7 Conclusion …………………………………………………………………………… 50
2 3.8 References ………………………………………………………………...………… 52
CHAPTER 4. mTOR inhibitors for the treatment of severe Congenital
Hyperinsulinism: perspectives on limited therapeutic success ………………………... 56
4.1 Abstract ………………………………………………………………………….…… 57
4.2 Background ……………………………………………………………………….…. 58
4.3 Methods …………………………………………………………………………...…. 59
4.4 Results …………………………………………………………………………..…… 62
4.5 Discussion …………………………………………………………………………… 67
4.6 Conclusion …………………………………………………………………………… 69
4.7 References ……………………………………………………………………...…… 70
CHAPTER 5. Vineland adaptive behavior scales to identify neurodevelopmental problems in children with Congenital Hyperinsulinism (CHI) …………………………… 73
5.1 Abstract …………………………………………………………………………….… 74
5.2 Background ………………………………………………….………………….…… 75
5.3 Methods ……………………………………………………………………………… 75
5.4 Results ………………………………………………………………………..……… 79
5.5 Discussion …………………………………………………………………………… 85
5.6 Conclusion …………………………………………………………………..………. 87
5.7 References ………………………………………………………………………….. 89
CHAPTER 6. GENERAL DISCUSSION ……………………………………………………….. 93
6.1 Outcomes of medically treated CHI patients …………………………………….. 93
6.2 mTOR inhibitors in CHI …………………………………………………..………… 95
6.3 Neurodevelopment in CHI …………………………………………………………. 97
6.4 References …………………………………………………………………………... 99
Word count: 20. 522
3 LIST OF FIGURES
Figure 1.1 Insulin secretion in the normal β-cell and the CHI β-cell due to KATP
channel mutations …...………………………………………………….……...……….. 14
Figure 1.2 Management of patients with CHI based on diazoxide response …...………….. 17
Figure 3.1 Maximum and present doses of diazoxide in children with CHI represented
as box and whisker plots ...…………………………….…………………..…………... 44
Supplementary Figure 3.A Mean blood glucose levels before and after prolonged
fasting in patients with resolved CHI …….………………………….…….…….…….. 45
Supplementary Figure 3.B Mean blood ketone (3 hydroxybutyrate) levels before
and after prolonged fasting in patients with resolved CHI …………………..………. 46
Figure 3.2 VABS-II scores as standard deviation scores for patients with persistent
CHI and resolved CHI …………………………………………………………………… 47
Figure 4.1 Cell proliferation is not suppressed by sirolimus treatment ….………………….. 66
Figure 4.2 Quantification of proliferation in CHI tissue following sirolimus ………………… 67
Figure 5.1 VABS-II scores in Early and Late CHI …………………………………………….. 80
Figure 5.2 Scatterplot of VABS-II Total scores for age at presentation of hypoglycaemia .. 82
Figure 5.3 Clustered box and whisker plots of VABS-II Total scores in Early-CHI and
Late-CHI ………………………………….………………………………………………. 83
Figure 5.4 Association of total behaviour scores with developmental delay ……………….. 84
4 LIST OF TABLES
Table 1.1 Medical treatment in CHI …………………………………..…………….…………… 20
Table 3.1 Patients’ characteristics …………………………………………..………….………. 37
Table 3.2 Genetic characterisation of patients with medically treated KATP CHI ……..……. 40
Table 4.1 Patients’ characteristics and glycaemic support before mTOR inhibitors ...……. 60
Table 4.2 Medical therapy and supporting glucose requirement at study entry ..………..… 61
Table 4.3 mTOR inhibitor treatment, dose, trough levels and duration of treatment …….... 63
Table 4.4 Response to treatment, duration of fasting and clinical adverse events ………... 64
Table 4.5 Monitoring data in follow-up assessments after mTOR inhibitor treatment …..… 65
Table 5.1 Individual and total VABS-II domain correlations with developmental delay by
objective assessment …..……………………………………………………………… 81
Appendix 5.A Clinical descriptors of patients ………………………...………………………… 90
5 ABSTRACT
Patients with Congenital hyperinsulinism (CHI) are at high risk of permanent brain damage due to recurrent episodes of severe hypoketotic hypoglycaemia. In order to prevent adverse neurodevelopmental outcomes, some patients with the most severe forms of the disease will need subtotal pancreatectomy, which will cause lifelong consequences.
In this thesis we demonstrate that conservatively treated patients with genetic forms of CHI due to KATP channel gene mutations (KATP CHI) show a reduction of severity over time and, in a significant proportion of patients, the disease is resolved including in patients with recessively inherited mutations. This supports conservative management in certain patients as opposed to subtotal pancreatectomy.
Sirolimus, an mTOR inhibitor with immunosuppressive and antiproliferative effects has been reported to be successful in a limited number of CHI patients. However, in our experience sirolimus has limited efficacy and poor safety profile and should not routinely be used in the management of medically-unresponsive CHI. Furthermore, the rate of cell proliferation in pancreatic tissue from patients treated with sirolimus is not decreased, illustrating the lack of effect of sirolimus in the CHI pancreas.
Assessing neurodevelopment is of paramount importance in CHI patients. The rate of adverse neurodevelopmental outcomes in our cohort of medically treated patients was no different to other cohorts and it was similar to cohorts of surgically treated patients. The use of Vineland Adaptive Behavior Scales Second Edition (VABS-II), a parent report questionnaire, has proved to be a reliable and specific tool to detect abnormal neurodevelopment in CHI patients. Male gender, later age at presentation and severity of disease are independent risk factors for worse neurodevelopment.
These data expand our knowledge in this complex condition and provide important information on the natural history of the disease, repurposed therapeutic opportunities as well as highlighting the relevance of neurodevelopmental surveillance.
6 DECLARATIONS AND COPYRIGHT STATEMENT
Declaration
I declare that no portion of the work referred to in the thesis has been submitted in support of an application for another degree or qualification of this or any other university or other institute of learning.
Copyright statement i. The author of this thesis (including any appendices and/or schedules to this thesis) owns certain copyright or related rights in it (the “Copyright”) and s/he has given The University of
Manchester certain rights to use such Copyright, including for administrative purposes. ii. Copies of this thesis, either in full or in extracts and whether in hard or electronic copy, may be made only in accordance with the Copyright, Designs and Patents Act 1988 (as amended) and regulations issued under it or, where appropriate, in accordance with licensing agreements which the University has from time to time. This page must form part of any such copies made. iii. The ownership of certain Copyright, patents, designs, trademarks and other intellectual property (the “Intellectual Property”) and any reproductions of copyright works in the thesis, for example graphs and tables (“Reproductions”), which may be described in this thesis, may not be owned by the author and may be owned by third parties. Such Intellectual Property and Reproductions cannot and must not be made available for use without the prior written permission of the owner(s) of the relevant Intellectual Property and/or Reproductions. iv. Further information on the conditions under which disclosure, publication and commercialisation of this thesis, the Copyright and any Intellectual Property and/or
Reproductions described in it may take place is available in the University IP Policy (see http://documents.manchester.ac.uk/DocuInfo.aspx?DocID=2442 0), in any relevant Thesis restriction declarations deposited in the University Library, The University Library’s regulations (see http://www.library.manchester.ac.uk/about/regulations/) and in The
University’s policy on Presentation of Theses.
7 Thesis in Journal Format
This thesis is written in the journal format in accordance with the “Presentation of Theses
Policy” provided by the University of Manchester. The three results chapters included in this thesis are presented in the form of manuscripts. Chapter three was published in Orphanet
Journal of Rare Diseases in December 2016. Chapter four is a modified version of the article published in The Journal of Clinical Endocrinology and Metabolism in December 2016.
Chapter five was published in Orphanet Journal of Rare Diseases in May 2017.
Chapter 3: Conservatively treated Congenital Hyperinsulinism (CHI) due to KATP channel gene mutations: reducing severity over time.
I collected data, analysed and interpreted the results. I contributed to writing the manuscript together with IB. MSE, IB, and MJD were responsible for design and methods. MSE, SEF,
MJD, KEC, JN, IB authored the manuscript. SE, LR, LB, ZM, MS, CH, RC, RP, NM and TR were involved in data collection, analysis and critical comments on the writing of the manuscript. MSE and IB were responsible for statistical analysis. All authors read and approved the final manuscript.
Chapter 4: mTOR Inhibitors for the Treatment of Severe Congenital Hyperinsulinism:
Perspectives on Limited Therapeutic Success.
I collected data (UK patients), analysed and interpreted the results in conjunction with IB and
MJD. BH and MJD performed cell proliferation studies in pancreatic tissue. I contributed to writing the manuscript in collaboration with MS, MJD, IB and JBA. LP, FPLB, EL, RR, CF,
CB, PL, CSM were involved in data collection (French patients) and provided critical comments to the manuscript. All authors read and approved the final manuscript.
Chapter 5: Vineland adaptive behavior scales to identify neurodevelopmental problems in children with Congenital Hyperinsulinism (CHI).
I was involved in collecting data, analysing and interpreting results in collaboration with ZM,
JN and IB. I contributed to writing the manuscript together with ZM, IB and JN.
IB, JN and SR conceived and designed the study. MSE, ZM, MM, HC and LR were involved in data collection. MSE, ZM, JN and IB analysed and interpreted the data, including statistical analysis. MS, RP, SR, MD and KC critically revised the manuscript. All authors
8 read and approved the final manuscript.
Publications and presentations generated from this thesis
Publications
Conservatively treated Congenital Hyperinsulinism (CHI) due to KATP channel gene mutations: reducing severity over time.
Salomon Estebanez M, Flanagan SE, Ellard S, Rigby L, Bowden L, Mohamed Z, Nicholson
J, Skae M, Hall C, Craigie R, Padidela R, Murphy N, Randell T, Cosgrove K, Dunne M,
Banerjee I.
Orphanet J Rare Dis. 2016;11(1):163. DOI: 10.1186/s13023-016-0547-3
mTOR Inhibitors for the Treatment of Severe Congenital Hyperinsulinism: Perspectives on
Limited Therapeutic Success.
Szymanowski M, Estebanez MS, Padidela R, Han B, Mosinska K, Stevens A, Damaj
L, Pihan-Le Bars F, Lascouts E, Reynaud R, Ferreira C, Bansept C, de Lonlay P, Saint-
Martin C, Dunne MJ, Banerjee I, Arnoux JB.
J Clin Endocrinol Metab. 2016;101(12):4719-4729. DOI:10.1210/jc.2016-2711
Vineland adaptive behavior scales to identify neurodevelopmental problems in children with
Congenital Hyperinsulinism (CHI).
Salomon-Estebanez M, Mohamed Z, Michaelidou M, Collins H, Rigby L, Skae M, Padidela
R, Rust S, Dunne M, Cosgrove K, Banerjee I, Nicholson J.
Orphanet J Rare Dis. 2017 May 22;12(1):96. doi: 10.1186/s13023-017-0648-7.
Conference presentations
Endocrine Abstracts (2016) 45 P56 I DOI: 10.1530/endoabs.45.P56
Poster: Doubtful efficacy of Sirolimus in the treatment of patients with severe congenital hyperinsulinism.
M Salomon-Estebanez, B Han, R Padidela, K Mosinska, A Stevens, M Dunne & I Banerjee.
44th Annual Meeting of the British Society for Paediatric Endocrinology and Diabetes
9 BSPED, November 2016, Nottingham.
Endocrine Abstracts (2016) 45 P53 | DOI: 10.1530/endoabs.45.P53
Poster: Vineland adaptive behavior scales to identify neurodevelopmental problems in children with Congenital Hyperinsulinism (CHI).
Z Mohamed, I Banerjee, M Michaelidou, M Estebanez, MJ Dunne, H Collins, L Rigby, L
Bowden, S Rust & J Nicholson.
44th Annual Meeting of the British Society for Paediatric Endocrinology and Diabetes
BSPED, November 2016, Nottingham.
Additional studies and publications not included for examination
A Multicenter Experience with Long-Acting Somatostatin Analogues in Patients with
Congenital Hyperinsulinism. van der Steen I, van Albada ME, Mohnike K, Christesen HT, Empting S, Salomon-Estebanez
M, Greve Rasmussen A, Verrijn Stuart A, van der Linde AAA, Banerjee I, Boot AM.
Horm Res Paediatr. 2018;89(2):82-89. doi: 10.1159/000485184.
Clinical Diversity in Focal Congenital Hyperinsulinism in Infancy Correlates With Histological
Heterogeneity of Islet Cell Lesions.
Craigie RJ, Salomon-Estebanez M, Yau D, Han B, Mal W, Newbould M, Cheesman E, Bitetti
S, Mohamed Z, Sajjan R, Padidela R, Skae M, Flanagan S, Ellard S, Cosgrove KE, Banerjee
I, Dunne MJ.
Front Endocrinol (Lausanne). 2018 Oct 17;9:619. doi: 10.3389/fendo.2018.00619.
Central venous catheter-associated thrombosis in children with congenital hyperinsulinism.
Yau D, Salomon-Estebanez M, Chinoy A, Grainger J, Craigie RJ, Padidela R, Skae
M, Dunne MJ, Murray PG, Banerjee I.
Endocrinol Diabetes Metab Case Rep. 2019 Jul 9;2019(1). doi: 10.1530/EDM-19-0032.
10 Unravelling the genetic causes of mosaic islet morphology in congenital hyperinsulinism.
Houghton JA, Banerjee I, Shaikh G, Jabbar S, Laver TW, Cheesman E, Chinnoy A, Yau
D, Salomon-Estebanez M, Dunne MJ, Flanagan SE.
J Pathol Clin Res. 2020 Jan;6(1):12-16. doi: 10.1002/cjp2.144. .
Research Projects and funding generated from this thesis
The successful conservative treatment of patients with KATP CHI demonstrated in this thesis influenced the design and delivery of the dasiglucagon clinical trial in which Royal
Manchester Children’s Hospital is the Chief Investigator site in the UK out of an international trial, and I am co-investigator.
Additionally, funding has been obtained for a research project aiming to understand the glycaemic phenotype in patients using Continuous Glucose Monitoring.
11 ACKNOWLEDGEMENTS
First and foremost I would like to thank my supervisors Professor Mark Dunne, Professor
Indi Banerjee, Dr Karen Cosgrove and Dr Donald Ward for the support and guidance throughout my MPhil study. I would like to express my deep and sincere gratitude to Indi for his constant support and invaluable advice throughout my career and for sharing his enthusiasm for congenital hyperinsulinism (CHI) with me.
I would like to extend my thanks to my lab colleagues (Bing Han, Saba Khan, Alex Ryan,
Karolina Mosinska and Walaa Mal) for accommodating me in the lab and teaching me about basic science. Special gratitude goes to my colleagues in the Paediatric Endocrinology
Department (Phil Murray, Mars Skae, Peter Clayton, Leena Patel, Raja Padidela, Zulf
Mughal, Amish Chinoy, Jackie Nicholson) for all I have learnt from them about CHI and
Paediatric Endocrinology and for the professional guidance and advice. Thanks for your appreciation and encouragement and for making the department such a great place to work.
I would also like to thank my parents for their endless love and support. My deepest gratitude goes to my dearest husband Bruno for his patient and loving support and encouragement.
And thanks to my lovely children Sofia (5 years) and Pablo (22 months) who are the joy of my life.
12 CHAPTER 1. INTRODUCTION
1.1 Congenital Hyperinsulinism
Congenital hyperinsulinism (CHI) is the most common cause of recurrent hypoglycaemia in infancy. It is due to excessive and dysregulated insulin secretion from pancreatic β-cells that can lead to severe hypoglycaemia and permanent brain damage [1].
Glucose is the primary stimulus for insulin release; in normal conditions, β-cells sense changes in plasma glucose concentration and respond by releasing corresponding amounts of insulin, which will maintain blood glucose levels within the normal range.
Insulin reduces the plasma glucose levels by stimulating glucose uptake in the muscle and adipocytes and by inhibiting glycogenolysis and gluconeogenesis.
Patients with CHI usually present in the neonatal period with recurrent, profound and unpredictable episodes of hyperinsulinaemic hypoglycaemia [2]. Due to the inhibition of glycogenolysis and gluconeogenesis, the brain is deprived of glucose, its primary source of energy. The raised insulin also inhibits lipolysis, preventing the generation of ketone bodies that can be used as an alternative energy substrate for the brain. Hence, this condition is associated with critical brain damage (epilepsy, cerebral palsy and neurological impairment) in up to 50% of cases [3-8].
1.2 Aetiology
CHI is a heterogeneous disease with transient and persistent forms. Transient CHI is usually associated with perinatal risk factors (being born small for gestational age, perinatal stress), whereas persistent forms of CHI are often caused by mutations in key genes involved in the precise control of insulin secretion [9,10].
Recessive inactivating mutations in the genes ABCC8 and KCNJ11, encoding the two subunits of the pancreatic β-cell adenosine triphosphate-sensitive potassium channel (KATP channel), SUR1 (sulfonylurea receptor 1) and Kir6.2 (inward-rectifier potassium channel) respectively, cause the most common and severe forms of CHI [11,12].
13 Mutations in ABCC8 and KCNJ11 reduce or completely abolish the activity of the KATP channel, leading to membrane depolarisation, opening of the voltage-gated calcium channels (VGCC), increase in intracellular calcium and unregulated insulin secretion, manifesting as severe hypoglycaemia, Figure 1.1
Figure 1.1 Insulin secretion in the normal β-cell and the CHI β-cell due to KATP channel mutations. In the normal β-cell, the glucose metabolism leads to an increase in the
ATP:ADP ratio, closure of the KATP channel, membrane depolarisation and opening of the voltage-gated calcium channel (VGCC). The increase in intracellular calcium stimulates insulin exocytosis. In the CHI β-cell with KATP channel mutations, there is an increase in insulin secretion even in the absence of glucose metabolism [13].
So far, mutations in twelve other genes encoding ion channels, enzymes, transcription factors and transporters, have been reported to be associated with CHI [14]. Some mutations occurring less frequently may be associated with CHI but are not directly causative of CHI. In about 45-55% of CHI patients, no genetic diagnosis can be established
[15].
Recently, a mutation in the α-subunit of the L-type calcium channel, encoded by CACNA1D, has been identified as a cause of CHI due to the increase in calcium influx into the β-cell, triggering insulin secretion [16]. Genetic mutations in certain enzymes (Glutamate dehydrogenase, Glucokinase, Short chain L-3-hydroxyacyl-CoA dehydrogenase,
14 Hexokinase 1, Phosphoglucomutase 1) can alter the β-cell metabolism and cause an increased ATP: ADP ratio, ultimately inducing insulin secretion [17]. A mutation in phosphomannomutase 2, a glycosylation enzyme has recently been described to cause CHI
[18]. Mutations in transcription factors (HNF1A, HNF4A, FOXA2) and transporters (UCP2,
SLC16A1) are associated with CHI, although the mechanisms underlying hyperinsulinism are not fully understood [19-22].
1.3 Histological forms of CHI
Histologically, CHI can be classified into three subgroups: focal, diffuse and atypical forms.
The focal form is characterised by a cluster of abnormal insulin-over secreting β-cells within a restricted area of the pancreas, usually < 10 mm. It is histologically determined by the presence of large β-cells with enlarged and irregular nuclei. This form is usually sporadic in inheritance and arises in individuals with a single paternally inherited recessive mutation in
ABCC8 or KCNJ11 [23]. When a second independent event of somatic loss of the maternal
11p allele (11p15.1 to 11p15.5) occurs in the β-cell during the development of the pancreas, that particular cell loses the activity of the KATP channel [24]. That maternal allele loss creates an imbalance in the imprinted genes in this region (maternally expressed tumour suppressor genes H19 and CDKN1C, and the paternally expressed IGF2), which confers disinhibited growth advantage to abnormal β-cells, eventually forming focal lesions through clonal expansion.
The diffuse form of CHI can be autosomal recessively inherited or dominantly inherited. β- cells throughout the pancreas are functionally abnormal [25], with variable involvement of islets. The islet pattern is preserved, but it contains functionally overactive β-cells with abundant cytoplasm and highly abnormal nuclei 3-4 times larger than the normal size.
Atypical forms of CHI are poorly defined. They account for 10% of patients undergoing pancreatectomy for treatment of CHI [26,27]. Affected patients are variably responsive to medications, and imaging with Fluorine-18-dihydrophenylalanine (18F-DOPA) positron emission tomography (PET)-CT scan, which differentiates between the focal and diffuse forms of CHI, is unable to identify the atypical subtype. The histology shows morphologic
15 mosaicism of the islets (large islets with occasional enlarged nuclei and shrunken islets with small nuclei) in a limited region of the pancreas [26,28,29].
1.4 Diagnosis and initial management
Patients with CHI suffer from recurrent episodes of profound and unpredictable hypoglycaemia. The diagnosis is confirmed by demonstration of detectable insulin with suppressed ketone bodies and free fatty acids at the time of hypoglycaemia. The requirement of a high glucose infusion rate (GIR), greater than 8 mg/kg/min, is a characteristic feature of CHI and supports the diagnosis [9,30], as well as a positive response to glucagon (a 1.0 mg intramuscular/intravenous dose of glucagon increases blood glucose levels by 1.7 mmol/L within 40 minutes [31]).
The primary goal when managing CHI patients is to achieve normoglycaemia and prevent adverse neurological outcomes. The rise in blood glucose to a safe level can be achieved by either administering additional glucose (enterally or most frequent intravenously) or increasing endogenous glucose production with glycogenolytic and gluconeogenic hormones such a glucagon [32,33]. Furthermore, medications that inhibit insulin secretion from β-cells
(diazoxide, somatostatin receptor agonists) and pancreatic resection are required for some patients [34,35].
Diazoxide is the first-line treatment in CHI. It opens the KATP channel binding to the intact
SUR1 component, thereby inhibiting the closure of the channel and preventing depolarisation, calcium influx and lastly insulin secretion [36]. It is effective in all forms of CHI where the KATP channel is intact. If there is no response to high dose of diazoxide (15 mg/kg/day), rapid ABCC8/KCNJ11 gene testing by Sanger sequencing should be performed to identify possible focal CHI. In diazoxide unresponsive CHI, second-line treatment with somatostatin receptor agonists (SSRA) should be commenced [35]. Genetic analysis is recommended in such patients. There is also a case to consider genetic analysis in patients who are clinically stable on a modest dose of diazoxide (greater than 5 mg/kg/day) as mutations in non- KATP channel genes may also be present.
Establishing the genetic diagnosis is of paramount importance in diazoxide-unresponsive
16 patients because the genetic result will guide further management. Patients with homozygous, compound heterozygous or maternally inherited ABCC8/KCNJ11 mutations will have a diffuse form of the disease, affecting all β-cells in the pancreas. In contrast, in patients with paternally inherited or “de novo” ABCC8/KCNJ11 mutations, an 18F-DOPA
PET-CT scan should be performed to rule out the possibility of a focal lesion, affecting only a small area of the pancreas [35]. Focal lesions can be cured with selective resection of the pancreatic lesion, whereas diffuse cases caused by homozygous or compound heterozygous ABCC8/KCNJ11 mutations are often resistant to medical therapy and may require subtotal pancreatectomy, Figure 1.2.
Figure 1.2 Management of patients with CHI based on diazoxide response. Genetic testing is indicated in diazoxide-unresponsive patients or when there is persistent diazoxide requirement. 18F-DOPA PET-CT scan to diagnose and localise focal lesion should be done in patients with paternally inherited KATP mutations and in patients with no genetic mutations that require intensive medical treatment. Medically unresponsive patients with diffuse disease will require subtotal pancreatectomy.
17 1.5 Medical Treatment
The management of CHI patients can be challenging. Although great progress has been achieved in the diagnostic approach to CHI with rapid genetic testing and 18F-DOPA PET-
CT scan, the therapeutic strategies are still highly limited. Medical treatment is not always effective and can be associated with life-threatening complications, Table 1.1. Subtotal pancreatectomy is still the only option in some patients and is associated with high incidence of diabetes mellitus and pancreatic exocrine insufficiency [37].
Initial glycaemic stabilisation is usually achieved by additional dextrose administration, in many cases using high concentration dextrose through a central venous catheter.
Continuous infusion of glucagon is useful to increase the blood glucose levels and reduce the dependence of large volumes of intravenous fluids, which will make patients more susceptible to complications. Glucagon can be administered by intravenous, subcutaneous or intramuscular route. It is currently only used for short-term control of hypoglycaemia as crystallisation in the infusion tubes has been a major practical problem during long-term use
[31,35].
Diazoxide is effective in suppressing insulin secretion and achieving euglycaemia when the
KATP channel is intact. It can cause fluid retention; therefore routine co-administration of chlorothiazide is advised [38], particularly in neonates. Other side effects are described in
Table 1.1.
In diazoxide-unresponsive patients, somatostatin receptor agonists (SSRA) are second- line treatment options. Octreotide binds to somatostatin receptors SSTR-2 and SSTR-5 and reduces insulin secretion via inhibition of insulin exocytosis and induction of β-cell membrane stability through the activation of G-protein gated inwardly rectifying K (GIRK) channels [39].
Octreotide has a short half-life of 100 minutes and has to be administered as multiple daily subcutaneous injections or by continuous subcutaneous or intravenous infusion.
Alternatively, long-acting somatostatin analogues (long-acting slow release octreotide and somatuline autogel) are administered once monthly and have been reported to be useful in long-term CHI management. Liver dysfunction is a common side effect, table 1.1 [40].
18 mTOR (mammalian target of rapamycin) inhibitors, sirolimus and everolimus are immunosuppressant agents with antiproliferative capacity that have been used in children with CHI when treatment with diazoxide and SSRA has not been effective [41]. Rapamycin is part of a complex that binds to and inhibits the serine/threonine kinase mammalian target of rapamycin (mTOR). This kinase is a key regulator of cell metabolism, growth and proliferation. Inhibitors of mTOR have been used, amongst others, in cancer patients and for the prophylaxis of renal transplantation rejection. The inhibition of mTOR by rapamycin results in cell cycle arrest in mid- to late G1 phase and thus has the potential to suppress tumour cell growth and inhibit cell proliferation [42].
Similar to its role in insulinomas, it is thought that the mTOR pathway is constitutively activated in diffuse CHI [43]. The successful use of sirolimus and everolimus in insulinoma patients prompted the experimental use of these drugs in CHI [41]. The mechanism of action of sirolimus in CHI is not clear, although an effect through modulation of mTOR pathways downstream of insulin receptor signaling and energy-sensing pathways in the β-cell has been suggested [43], as well as a reduction in β-cell proliferation and cell mass [44].
However, these conclusions were based upon limited histological studies and gene expression datasets that were poorly controlled [45].
The use in CHI patients is limited to small observational studies and case reports; the long- term experience and actual efficacy remains minimal [41,46,47]. In the initial study [41] four patients unresponsive to conventional medical treatment were treated with sirolimus, preventing subtotal pancreatectomy. The authors reported good glycaemic control after discontinuation of intravenous fluids and glucagon with no side effects after just one-year follow-up.
Other experimental treatments, including exendin-9-29, insulin receptor antibody and soluble glucagon are currently under investigation for the treatment of CHI patients who do not respond to conventional medical treatment [14].
19 Table 1.1 Medical treatment in CHI Medication Administration Dose Mechanism of action Side effects route
Diazoxide orally 5-15 mg/kg/day in 3 Opens the KATP channel Frequent: hypertrichosis, fluid retention. divided doses Reduces insulin secretion Rare: leukopaenia, thrombocytopaenia, hyperuricaemia, pericardial effusion, pulmonary hypertension Chlorothiazide orally 7-10 mg/kg/day in 2 Prevents fluid retention. Hyponatraemia, hypokalaemia divided doses Synergisticc effect with
diazoxide at the KATP channel Octreotide IV/SC 5-25 μg/kg/day in 3-4 Cell membrane stabiliser, Acute: anorexia, nausea, diarrhoea, hepatitis, long QT, divided doses, inhibits calcium mobilisation tachyphylaxis, necrotising enterocolitis. 35-50 μg/kg/day in some reduces insulin secretion Long-term: cholelithiasis, pituitary hormone suppression centres Somatuline deep SC/ IM Octreotide cumulative Same as octreotide Similar to octreotide, but unknown long-term effects autogel/slow monthly dose or total release dose of 15-60 mg every octreotide 4 weeks Glucagon IM 0.5-1.0 mg Stimulates glycogenolysis Nausea, vomits, necrolytic migratory erythema IV/SC 5-20 μg/kg/h and gluconeogenesis Sirolimus orally 1 mg/m2/day in 1 or 2 mTOR inhibitor. Reduces Immunosuppression, mucositis, hyperlipidaemia, doses, adjusted insulin secretion and β-cell hypertransaminasaemia, thrombocytosis, renal dysfunction, depending on levels proliferation neumonitis, sepsis, enteropathy IV: intravenous, SC: subcutaneous, IM: intramuscular
20 1.6 Outcomes of CHI
1.6.1 Natural history of the disease
Patients with CHI usually present with recurrent hypoglycaemia in the neonatal period, typically within the first week of life. However, in around 10% of cases [9] late-onset CHI, beyond the neonatal period may occur, particularly in a subset of patients with focal CHI as we have recently described [48].
Patients with transient CHI associated with perinatal risk factors normally respond to a small dose of diazoxide (5 mg/kg/day), which can be gradually weaned down and discontinued.
Most patients achieve disease resolution after several weeks [9].
In the majority of CHI patients it is not possible to establish a genetic diagnosis. Remission is more likely in this group of patients, as well as in diazoxide-responsive patients [9]. However, time to resolution is unpredictable and the mechanisms responsible for disease remission remain unknown.
The disease trajectory in patients with genetic forms of CHI is quite variable. In patients with focal CHI, focal lesionectomy is the treatment of choice as it is curative in most cases.
However, sometimes the focal lesion is located in the head of the pancreas or close to important anatomical structures such as the bile duct; the proximity to sensitive structures may complicate surgical procedures, which could potentially damage the bile duct and cause bile leak. Conservative medical management may be an option in these cases.
In contrast, subtotal pancreatectomy is the only realistic option in medically unresponsive patients with diffuse CHI. However, this procedure is not curative and a significant proportion
(40 - 60%) will continue to have hypoglycaemia post-surgery [4, 37, 49]. In the long term,
49% of patients will develop symptomatic exocrine pancreatic insufficiency and 96% will develop diabetes by age 11 years [37].
Progression from initial hyperinsulinaemic hypoglycaemia to diabetes in later life has been reported in patients with certain dominantly acting ABCC8 mutations and HNF4A mutations
[50,51]. The mechanisms responsible for this switch remain unknown. Patients with GLUD1
21 mutations typically present with hyperinsulinism-hyperammonaemia and seizures and show a good diazoxide response [52]. Response to diazoxide is variable in GCK patients; some of them are asymptomatic, others show a good diazoxide response and some others require subtotal pancreatectomy to control hypoglycaemia [17].
Due to the irreversible and lifelong consequences associated with subtotal pancreatectomy and the relatively recent use of drugs such as long-acting somatostatin analogues and sirolimus, there is a trend to avoid subtotal pancreatectomy and manage severe CHI patients conservatively. There is however, scarce data about the natural history and clinical outcomes of medically treated CHI patients.
1.6.2 Neurodevelopmental outcomes
The important advances in the genetic diagnosis and the introduction of the 18F- DOPA
PET-CT scan have greatly improved the management of patients with CHI. However, rates of adverse neurodevelopmental outcomes have not decreased over time [14], with frequency of incidence varying between 26% and 48% in different cohorts [14].
Persistent and profound episodes of hypoketotic hypoglycaemia can have a devastating effect on the neonatal developing brain. Hypoglycaemic injury can cause a wide spectrum of problems (motor and speech delay, learning difficulties, epilepsy, visual impairment, behavioural problems, microcephaly, cerebral palsy) that severely affect patients’ quality of life.
Despite focal lesionectomy being curative, the rates of neurodevelopmental impairment are similar in patients with diffuse and focal CHI [6-8]. Furthermore, abnormal neurodevelopment occurs in patients with transient CHI with a similar frequency to those with permanent forms of CHI [5], suggesting that the initial insult of a period of either deep or persistent hypoglycaemia before diagnosis and appropriate treatment are established, contributes to adverse outcomes. It is therefore vital to treat hypoglycaemia promptly and appropriately to reduce the risk of long-term disability and morbidity.
22 Regular neurodevelopmental assessments are essential to identify children with neurodevelopmental needs and to ensure appropriate physical and educational support. The use of validated parent report questionnaires, such as the Vineland Adaptive Behavior
Scales II© (VABS-II; Pearson Education Incorporated, San Antonio, Texas) is appropriate in the context of CHI. VABS-II questionnaires can be used as a developmental screening tool to prompt referral for a formal developmental assessment.
1.7 References
1. De León DD, Stanley CA. Mechanisms of Disease: advances in diagnosis and treatment of hyperinsulinism in neonates. Nat Clin Pract Endocrinol Metab. 2007;3(1):57-68. 1. Dunne MJ, Cosgrove KE, Shepherd RM, Aynsley-Green A, Lindley KJ. Hyperinsulinism in infancy: from basic science to clinical disease. Physiol Rev. 2004;84(1):239-275. 2. Menni F, de Lonlay P, Sevin C, Touati G, Peigne C, Barbier V, et al. Neurologic outcomes of 90 neonates and infants with persistent hyperinsulinemic hypoglycemia. Pediatrics. 2001;107:476-479. 3. Meissner T, Wendel U, Burgard P, Schaetzle S, Mayatepek E. Long-term follow-up of 114 patients with congenital hyperinsulinism. Eur J Endocrinol. 2003;149:43-51. 4. Avatapalle HB, Banerjee I, Shah S, Pryce M, Nicholson J, Rigby L, et al. Abnormal Neurodevelopmental Outcomes are Common in Children with Transient Congenital Hyperinsulinism. Front Endocrinol (Lausanne). 2013;4:60. 5. Lord K, Radcliffe J, Gallagher PR, Adzick NS, Stanley CA, De Leon DD. High risk of diabetes and neurobehavioral deficits in individuals with surgically treated Hyperinsulinism. J Clin Endocrinol Metab. 2015;100(11):4133-4139. 6. Helleskov A, Melikyan M, Globa E, Shcherderkina I, Poertner F, Larsen AM, et al. Both Low Blood Glucose and Insufficient Treatment Confer Risk of Neurodevelopmental Impairment in Congenital Hyperinsulinism: A Multinational Cohort Study. Front Endocrinol (Lausanne). 2017;8:156. 7. Ludwig A, Enke S, Heindorf J, Empting S, Meissner T, Mohnike K. Formal Neurocognitive Testing in 60 Patients with Congenital Hyperinsulinism. Horm Res Paediatr. 2018;89(1):1-6. 8. Banerjee I, Skae M, Flanagan SE, Rigby L, Patel L, Didi M, et al. The contribution of rapid KATP channel gene mutation analysis to the clinical management of children with congenital hyperinsulinism. Eur J Endocrinol. 2011;164(5):733-740. 9. Stanley CA, Rozance PJ, Thornton PS, De León DD, Harris D, Haymond MW, et al. Re-evaluating transitional neonatal hypoglycemia: mechanism and implications for management. J Pediatr. 2015;166:1520-5. 10. Nestorowicz A, Wilson BA, Schoor KP, Inoue H, Glaser B, Landau H, et al. Mutations in the sulonylurea receptor gene are associated with familial hyperinsulinism in Ashkenazi Jews. Hum Mol Genet. 1996;5:1813-22. 11. Dunne MJ, Kane C, Shepherd RM, Sanchez JA, James RF, Johnson PR, et al. Familial persistent hyperinsulinemic hypoglycemia of infancy and mutations in the sulfonylurea receptor. N Engl J Med. 1997;336:703-706.
23 12. Lindley KJ, Dunne MJ. Contemporary strategies in the diagnosis and management of neonatal hyperinsulinaemic hypoglycaemia. Early Hum Dev. 2005;81:61-72. 13. Banerjee I, Salomon-Estebanez M, Shah P, Nicholson J, Cosgrove KE, Dunne MJ. Therapies and outcomes of congenital hyperinsulinism-induced hypoglycaemia. Diabet Med. 2019;36(1):9-21. 14. Kapoor RR, Flanagan SE, Arya VB, Shield JP, Ellard S, Hussain K. Clinical and molecular characterisation of 300 patients with congenital hyperinsulinism. Eur J Endocrinol. 2013;168(4):557-64. 15. Flanagan SE, Vairo F, Johnson MB, Caswell R, Laver TW, Lango Allen H, et al. A CACNA1D mutation in a patient with persistent hyperinsulinaemic hypoglycaemia, heart defects, and severe hypotonia. Pediatr Diabetes. 2017;18:320-323. 16. Stanley C.A. Perspective on the genetics and diagnosis of congenital hyperinsulinism disorders. J Clin Endocrinol Metab. 2016;101:815-826. 17. Cabezas OR, Flanagan SE, Stanescu H, García-Martínez E, Caswell R, Lango-Allen H, et al. Polycystic Kidney Disease with Hyperinsulinemic Hypoglycemia Caused by a Promoter Mutation in Phosphomannomutase 2. J Am Soc Nephrol. 2017;28:2529- 2539. 18. Giri D, Vignola ML, Gualtieri A, Scagliotti V, McNamara P, Peak M, et al. Novel FOXA2 mutation causes Hyperinsulinism, Hypopituitarism with Craniofacial and Endoderm-derived organ abnormalities. Hum Mol Genet. 2017;26:4315-4326. 19. Vajravelu ME, Chai J, Krock B, Baker S, Langdon D, Alter C, De León DD. Congenital Hyperinsulinism and Hypopituitarism Attributable to a Mutation in FOXA2. J Clin Endocrinol Metab. 2018;103(3):1042-1047. 20. Gonzalez-Barroso MM, Giurgea I, Bouillaud F, Anedda A, Bellanne-Chantelot C, Hubert L, et al. Mutations in UCP2 in congenital hyperinsulinism reveal a role for regulation of insulin secretion. PLoS One. 2008;3:e3850. 21. Otonkoski T, Kaminen N, Ustinov J, Lapatto R, Meissner T, Mayatepek E, et al. Physical exercise-induced hyperinsulinemic hypoglycemia is an autosomal-dominant trait characterized by abnormal pyruvate-induced insulin release. Diabetes. 2003; 52:199-204. 22. De Lonlay P, Fournet JC, Rahier J, Gross-Morand MS, Poggi-Travert F, Foussier V, et al. Somatic deletion of the imprinted 11p15 region in sporadic persistent hyperinsulinemic hypoglycemia of infancy is specific of focal adenomatous hyperplasia and endorses partial pancreatectomy. J Clin Invest. 1997;100(4):802- 807. 23. Verkarre V, Fournet JC, De Lonlay P, Gross-Morand MS, Devillers M, Rahier J, et al. Paternal mutation of the sulfonylurea receptor (SUR1) gene and maternal loss of 11p15 imprinted genes lead to persistent hyperinsulinism in focal adenomatous hyperplasia. J Clin Invest. 1998;102(7):1286-1291. 24. Goossens A, Gepts W, Saudubray JM, Bonnefont JP, Nihoul-Fekete, Heitz PU, Kloppel G. Diffuse and focal nesidioblastosis. A clinicopathological study of 24 patients with persistent neonatal hyperinsulinemic hypoglycemia. Am J Surg Pathol. 1989;13:766-775. 25. Sempoux C, Capito C, Bellanne-Chantelot C, Verkarre V, de Lonlay P, Aigrain Y, et al. Morphological mosaicism of the pancreatic islets: a novel anatomopathological form of persistent hyperinsulinemic hypoglycemia of infancy. J Clin Endocrinol Metab. 2011;96:3785-3793. 26. Shi Y, Avatapalle HB, Skae MS, Padidela R, Newbould M, Rigby L, et al. Increased plasma incretin concentrations identifies a subset of patients with persistent
congenital hyperinsulinism without KATP channel gene defects. J Pediatr. 2015; 166:191-194.
24 27. Hussain K, Flanagan SE, Smith VV, Ashworth M, Day M, Pierro A, Ellard S. An ABCC8 gene mutation and mosaic uniparental isodisomy resulting in atypical diffuse congenital hyperinsulinism. Diabetes. 2008;57:259-63. 28. Han B, Mohamed Z, Estebanez MS, Craigie RJ, Newbould M, Cheesman E, et al. Atypical forms of congenital hyperinsulinism in infancy are associated with mosaic patterns of immature islet cells. J Clin Endocrinol Metab. 2017;102:3261-3267. 29. Mohamed Z, Arya VB, Hussain K. Hyperinsulinaemic hypoglycaemia: genetic mechanisms, diagnosis and management. J Clin Res Pediatr Endocrinol. 2012; 4(4):169-81. 30. Palladino AA, Stanley CA. A specialized team approach to diagnosis and medical versus surgical treatment of infants with congenital hyperinsulinism. Semin Pediatr Surg. 2011;20:32-7. 31. Hussain K, Aynsley-Green A, Stanley CA. Medications used in the treatment of hypoglycemia due to congenital hyperinsulinism of infancy. Pediatr Endocrinol Rev. 2004;2:163-167. 32. Arnoux JB, Verkarre V, Saint-Martin C, Montravers F, Brassier A, Valayannopoulos V, et al. Congenital hyperinsulinism: current trends in diagnosis and therapy. Orphanet J Rare Dis. 2011;6:63. 33. Shah P, Demirbilek H, Hussain K. Persistent hyperinsulinaemic hypoglycaemia in infancy. Semin Pediatr Surg. 2014;23(2):76-82. 34. Banerjee I, Avatapalle B, Padidela R, Stevens A, Cosgrove KE, Clayton PE, Dunne MJ. Integrating genetic and imaging investigations into the clinical management of congenital hyperinsulinism. Clin Endocrinol. 2013;78(6):803-13. 35. Panten U, Burgfeld J, Goerke F, Rennicke M, Schwanstecher M, Wallasch A, et al. Control of insulin secretion by sulfonylureas, meglitinide and diazoxide in relation to their binding to the sulfonylurea receptor in pancreatic islets. Biochem Pharmacol. 1989;38(8):1217-29. 36. Arya VB, Senniappan S, Demirbilek H, Alam S, Flanagan SE, Ellard S, Hussain K. Pancreatic endocrine and exocrine function in children following near-total pancreatectomy for diffuse congenital hyperinsulinism. PLoS One. 2014;9:e98054. 37. Touati G, Poggi-Travert F, Ogier de Baulny H, Rahier J, Brunelle F, Nihoul-Fekete C, et al. Long-term treatment of persistent hyperinsulinaemic hypoglycaemia of infancy with diazoxide: a retrospective review of 77 cases and analysis of efficacy-predicting criteria. Eur J Pediatr. 1998;157:628-33. 38. Kailey B, van de Bunt M, Cheley S, Johnson PR, MacDonald PE, Gloyn AL, et al. SSTR2 is the functionally dominant somatostatin receptor in human pancreatic β- and α-cells. Am J Physiol Endocrinol Metab. 2012;303(9):E1107-E1116. 39. van der Steen I, van Albada ME, Mohnike K, Christesen HT, Empting S, Salomon- Estebanez M, et al. A Multicenter Experience with Long- Acting Somatostatin Analogues in Patients with CongenitalHyperinsulinism. Horm Res Paediatr. 2018;89(2):82-89. 40. Senniappan S, Alexandrescu S, Tatevian N, Shah P, Arya V, Flanagan S, et al. Sirolimus therapy in infants with severe hyperinsulinemic hypoglycemia. N Engl J Med. 2014;370(12):1131-7. 41. Barlow AD, Nicholson ML, Herbert TP. Evidence for Rapamycin Toxicity in Pancreatic β-Cells and a Review of the Underlying Molecular Mechanisms. Diabetes. 2013;62(8):2674-2682. 42. Alexandrescu S, Tatevian N, Olutoye O, Brown RE. Persistent hyperinsulinemic hypoglycemia of infancy: constitutive activation of the mTOR pathway with associated exocrine-islet transdifferentiation and therapeutic implications. Int J Clin Exp Pathol. 2010;3(7):691-705.
25 43. Senniappan S, Brown RE, Hussain K. Genomic and morphoproteomic correlates implicate the IGF-1/mTOR/Akt pathway in the pathogenesis of diffuse congenital hyperinsulinism. Int J Clin Exp Pathol. 2016;9(2):548-562. 44. Banerjee I, De Leon D, Dunne MJ. Extreme caution on the use of sirolimus for the congenital hyperinsulinism in infancy patient. Orphanet J Rare Dis. 2017;12(1):70. 45. Shah P, Arya VB, Flanagan SE, Morgan K, Ellard S, Senniappan S, Hussain K. Sirolimus therapy in a patient with severe hyperinsulinaemic hypoglycaemia due to a compound heterozygous ABCC8 gene mutation. J Pediatr Endocrinol Metab. 2015;28(5-6):695-699. 46. Minute M, Patti G, Tornese G, Faleschini E, Zuiani C, Ventura A. Sirolimus therapy in congenital hyperinsulinism: a successful experience beyond infancy. Pediatrics. 2015;136(5):e1373-e1376. 47. Craigie RJ, Salomon-Estebanez M, Yau D, Han B, Mal W, Newbould M, et al. Clinical Diversity in Focal Congenital Hyperinsulinism in Infancy Correlates With Histological Heterogeneity of Islet Cell Lesions. Front Endocrinol (Lausanne). 2018;9:619. 48. Beltrand J, Caquard M, Arnoux JB, Laborde K, Velho G, Verkarre V, et al. Glucose metabolism in 105 children and adolescents after pancreatectomy for congenital hyperinsulinism. Diabetes Care. 2012;35:198-203. 49. Kapoor RR, Flanagan SE, James CT, McKiernan J, Thomas AM, Harmer SC, et al. Hyperinsulinaemic hypoglycaemia and diabetes mellitus due to dominant ABCC8/KCNJ11 mutations. Diabetologia. 2011;54(10):2575-83. 50. Pearson ER, Boj SF, Steele AM, Barrett T, Stals K, Shield JP, et al. Macrosomia and hyperinsulinaemic hypoglycaemia in patients with heterozygous mutations in the HNF4A gene. PLoS Med. 2007;4:e118. 51. Palladino AA, Stanley CA. The hyperinsulinism/hyperammonemia syndrome. Rev Endocr Metab Disord. 2010;11(3):171-8.
26 2. PROJECT AIMS AND OBJECTIVES
Subtotal pancreatectomy has classically been the therapeutic option for patients with severe
CHI unresponsive to diazoxide and octreotide. In recent years, there has been a trend to avoid subtotal pancreatectomy and manage patients conservatively. The currently available medical treatments for CHI have variable efficacy and some are associated with life- threatening complications. Sirolimus, an mTOR inhibitor has been proposed as a successful treatment for patients with severe CHI. The safety and efficacy of long-term medication use needs to be monitored.
There is currently limited data on the natural history of CHI patients that have been medically managed in terms of severity over time, disease resolution or neurodevelopmental outcomes. Preventing adverse neurological outcomes is the goal of the intensive management of CHI patients. It is important to identify risk factors associated with worse neurodevelopmental outcomes and to use a robust screening tool for early detection of neurodevelopmental problems in patients with CHI.
The aim of chapter 3 is:
To assess the variation in intensity of medical treatment over time and the outcomes
of medically treated children with mutations in the KATP channel genes (KATP CHI).
Objectives:
- To select conservatively treated patients with KATP CHI from a specialist centre
for CHI over a ten-year period (from April 2006 to July 2016).
- To assess treatment dose reduction over time and to identify patients that
achieved disease resolution collecting information from medical records.
- To collect information about outcomes including neurodevelopment, from
medical records and Vineland Adaptive Behavior Scales, version II (VABS-II),
when available.
27 The search for new effective therapeutic agents to avoid subtotal pancreatectomy and its associated complications has prompted the use of drugs such as sirolimus in CHI patients despite limited data about its efficacy, safety profile or long-term outcomes.
The aim of chapter 4 is:
To review the efficacy and safety profile of sirolimus and to assess the impact of
sirolimus in CHI pancreatic tissue.
Objectives:
- To select patients with severe diffuse CHI unresponsive to maximum dose of
diazoxide or somatostatin receptor agonists from a specialist centre for CHI over
a two-year period (from June 2014 to June 2016).
- To assess the efficacy of sirolimus as judged by a reduction in GIR or glucagon
requirement and improved fasting tolerance with sustainable euglycaemia.
- To monitor side effects with regular blood tests and clinical assessments.
- To assess rates of pancreatic proliferation (by immunostaining with Ki67) in
pancreatic tissue from CHI patients treated with sirolimus compared to age-
mached controls and age-mathed CHI tissues not treated with sirolimus.
Unfortunately, recent advances in CHI medical care have not been translated into better developmental outcomes, with abnormal neurodevelopmental rates being stable around 40% over the years. Regular follow-up and developmental assessments are a priority in CHI care.
The use of parent report questionnaires, such as VABS-II can be a useful screening tool to detect developmental issues and ensure adequate support.
The aim of chapter 5 is:
To investigate performance of VABS-II to identify developmental delay in CHI and to
identify patient factors correlating with VABS-II scores.
28 Objectives:
- To collect data on VABS-II questionnaires completed by parents of CHI patients
that presented consecutively to a specialist CHI treatment centre between 2013
and 2015.
- To compare VABS-II scores with objective developmental assessment
performed by developmental paediatricians, clinical psychologists and
educational psychologists.
- To investigate correlation of VABS-II scores with age at presentation, gender and
CHI severity.
29 CHAPTER 3
Conservatively treated Congenital Hyperinsulinism (CHI) due to KATP channel gene mutations: reducing severity over time
Maria Salomon-Estebanez1,8, Sarah E Flanagan2, Sian Ellard2, Lindsey Rigby1, Louise
Bowden1, Zainab Mohamed3, Jacqueline Nicholson4, Mars Skae1, Caroline Hall5, Ross
Craigie6, Raja Padidela1, Nuala Murphy7, Tabitha Randell3, Karen E Cosgrove8, Mark J
Dunne8, Indraneel Banerjee1,8.
1. Department of Paediatric Endocrinology, Royal Manchester Children’s Hospital, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, UK 2. Institute of Biomedical and Clinical Science, University of Exeter Medical School, RILD Building, RD&E Hospital Wonford, Barrack Road, Exeter, EX2 5DW, UK 3. Department of Paediatric Endocrinology and Diabetes, Nottingham Children's Hospital, Nottingham University Hospitals, Derby Road, Nottingham, NG7 2UH, UK 4. Paediatric Psychosocial Department, Royal Manchester Children’s Hospital, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, UK 5. Therapy and Dietetic Department, Royal Manchester Children’s Hospital, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, UK 6. Department of Paediatric Surgery, Royal Manchester Children’s Hospital, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, UK 7. Department of Diabetes and Endocrinology, Children’s University Hospital, Temple Street, Dublin, Ireland 8. Faculty of Biology, Medicine and Health, University of Manchester, Oxford Rd, Manchester, M13 9PL, UK
Published in Orphanet J Rare Dis. 2016 Dec 1;11(1):163. DOI:10.1186/s13023-016-0547-3
30 3.1 Abstract
Background: Patients with Congenital Hyperinsulinism (CHI) due to mutations in KATP channel genes (KATP CHI) are increasingly treated by conservative medical therapy without pancreatic surgery. However, the natural history of medically treated KATP CHI has not been described; it is unclear if the severity of recessively and dominantly inherited KATP CHI reduces over time. We aimed to review variation in severity and outcomes in patients with
KATP CHI treated by medical therapy.
Methods: Twenty-one consecutively presenting patients with KATP CHI with dominantly and recessively inherited mutations in ABCC8/KCNJ11 were selected in a specialised CHI treatment centre to review treatment outcomes. Medical treatment included diazoxide and somatostatin receptor agonists (SSRA), octreotide and somatuline autogel. CHI severity was assessed by glucose infusion rate (GIR), medication dosage and tendency to resolution. CHI outcome was assessed by glycaemic profile, fasting tolerance and neurodevelopment.
Results: CHI presenting at median (range) age 1 (1, 240) days resolved in 15 (71%) patients at age 3.1 (0.2, 13.0) years. Resolution was achieved both in patients responsive to diazoxide (n=8, 57%) and patients responsive to SSRA (n=7, 100%) with earlier resolution in the former [1.6 (0.2, 13.0) v 5.9 (1.6, 9.0) years, p=0.08]. In 6 patients remaining on treatment, diazoxide dose was reduced in follow up [10.0 (8.5, 15.0) to 5.4 (0.5, 10.8) mg/kg/day, p=0.003]. GIR at presentation did not correlate with resolved or persistent CHI
[14.9 (10.0, 18.5) v 16.5 (13.0, 20.0) mg/kg/min, p=0.6]. The type of gene mutation did not predict persistence; resolution could be achieved in recessively-inherited CHI with homozygous (n=3), compound heterozygous (n=2) and paternal mutations causing focal CHI
(n=2). Mild developmental delay was present in 8 (38%) patients; adaptive functioning assessed by Vineland Adaptive Behavior Scales questionnaire showed a trend towards higher standard deviation scores (SDS) in resolved than persistent CHI [-0.1 (-1.2, 1.6) v -1.2
(-1.7, 0.03), p=0.1].
Conclusions: In KATP CHI patients managed by medical treatment only, severity is reduced over time in the majority, including those with compound heterozygous and homozygous mutations in ABCC8/KCNJ11. Severity and treatment requirement should be assessed periodically in all children with KATP CHI on medical therapy.
31 3.2 Background
Congenital Hyperinsulinism in Infancy (CHI) is a rare disorder causing severe debilitating hypoglycaemia, usually presenting in infancy [1, 2]. Hypoglycaemia due to CHI can have a deleterious impact on early life brain function, with several cohorts reporting adverse neurodevelopmental outcomes in a third to a half of patients [3-6]. The frequency of hypoglycaemia-related brain injury in the CHI population as a whole has not reduced despite optimisation of diagnosis and treatment over the last decade. The burden of morbidity in
CHI continues to be a major problem for individuals and health care professionals; therefore, a greater focus is required on understanding variations in disease severity.
Genetic understanding of CHI has progressed rapidly with a significant proportion of CHI cases found to have underlying genetic causes, most frequently mutations in the KATP channel genes, ABCC8 and KCNJ11 [7, 8]. KATP channel genotyping has stratified treatment protocols of focal and diffuse CHI with paternal heterozygosity most commonly associating with focal CHI and maternal heterozygous, homozygous or compound heterozygous mutations in ABCC8/KCNJ11 associating with diffuse disease [2]. Although paternal heterozygosity has a higher predilection for focal CHI, additional investigation such as 18- fluoro-dopa PET-CT scanning is necessary to localise the lesion in focal CHI; a significant proportion, as many as half with paternal heterozygous mutations in some reports may have diffuse CHI [9] which could be explained by dominant inheritance or inability to identify a maternal mutation in recessively-inherited disease.
It is recognised that pancreatectomy, either lesionectomy for focal lesions or subtotal pancreatectomy for severe diffuse CHI is a well-established treatment choice for CHI.
However; increasingly there is a shift to conservative medical management particularly in the case of diffuse CHI which is traditionally treated by near total pancreatectomy. Indeed, some children with focal CHI in the head of the pancreas proximal or abutting the bile duct may benefit from conservative treatment due to the nature of the surgical complexity involved. In our centre, the frequency of patients (with KATP and non-KATP channel gene mutations) undergoing pancreatic surgery as a proportion of new patients referred to the service has reduced from 18% in 2007-2008 to 6 - 7% in 2014-2015.
32 A number of case reports of spontaneous resolution of disease have been reported [10-12], mostly in those without known genetic mutations, while cohort studies in different countries have characterised surgical outcomes only [4, 7, 8, 13]. Long-term conservative treatment with diazoxide and octreotide without requirement for pancreatic surgery has also been reported in patients with and without KATP channel gene mutations [12, 14, 15]; however these observations do not offer insight into the evolution of disease severity and if treatment response improves or worsens over time. Therefore, disease trajectories of medically treated KATP CHI remain poorly understood. It is important to understand the trends in severity of CHI to modify and individualise the intensity of medical therapy. Here we have studied a cohort of medically managed KATP CHI patients to examine outcomes of disease in follow up assessments.
3.3 Aims
The aims of our study were to assess temporal changes in treatment intensity in children with KATP CHI, and to review outcomes of medically treated KATP CHI patients in follow up assessments.
3.4 Methods
A cohort of patients with KATP CHI (mutations in ABCC8/KCNJ11) treated by medical therapy
(n=21) was identified from a group of patients (n=404) in a specialist centre for CHI between
April 2006 and July 2016, with local Research Ethics approval. Genetic investigations were performed in 269 patients only within the cohort. In the remainder, genetic investigations were not performed because CHI resolved in early infancy or patients remained on low dose diazoxide. In those undergoing genetic testing, 71 patients had mutations in
ABCC8/KCNJ11, 10 patients had mutations in other genes related to CHI (HNF4A, GCK,
HADH, GLUD1) and 10 patients had variants of uncertain clinical significance. Within the group of 71 patients with ABCC8/KCNJ11 mutations, 39 patients underwent pancreatic surgical treatment (subtotal pancreatectomy or focal lesionectomy); patients who were not surgically treated, i.e. medically treated (n=21) were recruited to the study. Eleven patients who were also medically treated were excluded because they either presented between
January 2016 and July 2016, or insufficient clinical information was available in follow up.
33 The diagnosis of CHI was made in patients presenting to this centre using well-established criteria [1, 2]. Patients underwent rapid KATP channel gene mutation analysis as per protocol, as previously reported [10]. Variants either previously reported or considered likely to be pathogenic were included in the cohort. One variant reported as pathogenic in our patient but classified elsewhere as being a variant of uncertain significance was also included.
The diagnosis of focal CHI was made on the basis of a paternal heterozygous mutation in
ABCC8/KCNJ11 and confirmed by identification of a solitary lesion in the pancreas during
18-fluoro-dopa PET-CT scanning [2]. Those with no clear foci were diagnosed as diffuse
CHI. Diffuse CHI was also presumed if the patient had maternal heterozygous, homozygous, or compound heterozygous mutations in ABCC8/KCNJ11, for which 18-fluoro-dopa PET-CT scans were not performed. Patients with ABCC8/KCNJ11 mutations who required either lesionectomy for focal CHI or subtotal pancreatectomy for diffuse CHI were excluded from the cohort. Patients who underwent pancreatic biopsy or minimal resection while continuing medical therapy were included in the cohort.
Treatment variations were made on clinical grounds and individualised to patient need. Oral diazoxide was used as first line treatment, while somatostatin agonists (SSRA, octreotide, somatuline) were used as second line treatment. Carbohydrate supplements to increase energy content of milk and polyunsaturated fatty acids (PUFA) used in the management of diazoxide responsive CHI were considered as food supplements and did not preclude inclusion to the cohort [16]. The dose of Eicosapentaenoic acid (EPA) component of omega-
3 fatty acid was allowed in a range of 240-480 mg per day. Responsiveness to diazoxide as treatment for CHI was determined by noting satisfactory glucose profiling and fasting tolerance as described previously [16]. Responsiveness to SSRA was determined in a similar manner.
Children had resolution of CHI if treatment was minimised and withdrawn completely with maintenance of satisfactory glucose profiles (95% values > 3.5 mmol/L) on home glucose monitoring or subcutaneous continuous glucose monitoring (CGM) [10, 16]. To achieve resolution of CHI, satisfactory fasting tolerance was mandatory with end of fast blood glucose > 3.0 mmol/L, suppressed insulin concentrations and blood ketones > 1.0 mmol/L
34 measured by point of care testing and/or laboratory analysis of 3 hydroxybutyrate. Follow-up consisted of telephone reviews every 2 weeks for the first 4 months, followed by clinic reviews at 4 monthly intervals by a multi-disciplinary team including two specialist nurse practitioners, two dietitians, a speech and language therapist and a clinical psychologist. At each review, glucose profile was assessed and medication adjusted accordingly. Children who demonstrated resolution of CHI were reviewed in clinic appointments every 6 months by a clinician and specialist nurse practitioner without wider multi-disciplinary team input.
Annual home blood glucose profiles were assessed to determine glycaemic status and to ensure continuing euglycaemia. Oral glucose tolerance testing was not performed routinely in all children undergoing spontaneous resolution, in the absence of information regarding long-term utility and difficulty in administering the test in young children. Instead, home blood glucose profiling was assessed and correlated with symptoms of hypoglycaemia and hyperglycaemia. Pancreatic biopsy was not routinely undertaken in patients enrolled in the cohort. However, for patients in whom a pancreatic biopsy was undertaken as a partial resection, the tissue was analysed for characteristics of focal and diffuse CHI [17].
In addition to glycaemic outcomes in follow up assessment, the Vineland Adaptive Behavior
Scales, version II (VABS-II), a questionnaire completed by parents was used to assess adaptive functioning in the domains of communication, daily living skills, social skills and motor skills after age 1.5 years (www.pearsonclinical.com). Information was also obtained on the prevalence of seizures and delayed development in clinical assessment [3]. Auxology parameters were reviewed at the two-year follow up assessment and measurements were converted to Standard Deviation Scores (SDS) [18]. Statistical analysis was performed by
IBM-SPSS version 23.0 (IBM incorporated, New York, USA); Mann-Whitney test was performed to test differences between non-parametric independent variables while paired t- tests were used to test difference between paired samples.
35 3.5 Results
Patient characteristics
Twenty-one patients presented with hypoglycaemia at a median age (range) 1 day (1 day, 8 months) with glucose 1.7 (0.1, 2.6) mmol/L, insulin 97.2 (16.8, 234.0) pmol/L and glucose infusion rate 14.9 (10.0, 20.0) mg/kg/min. Birth weight SDS was 2.0 (-0.5, +3.8), with weight
SDS and height SDS at age 2 years being +1.7 (-1.4, +3.8) and +1.0 (-2.0, +2.2) respectively. Information on age at presentation, focal and diffuse CHI, medication, feeding and neurodevelopment has been provided in Table 3.1 with gene mutation status provided in
Table 3.2.
Recessively acting mutations were identified in 7 (33%) patients; 3 patients had homozygous mutations, 2 patients had compound heterozygous mutations in ABCC8 and 2 patients had focal CHI (one paternally inherited mutation in ABCC8 and one paternally inherited mutation in KCNJ11). A single heterozygous mutation was identified in 14 (67%) patients; 5 patients had maternally inherited ABCC8 mutations, 2 patients had de novo ABCC8 mutations (no mutations identified in parents), 1 patient had a paternally inherited ABCC8 mutation without focal CHI, 5 patients had paternally inherited KCNJ11 mutations without focal CHI and 1 patient had a maternally inherited KCNJ11 mutation.
36 Table 3.1 Patients’ characteristics
Patient Current Age at Resolved at Focal/Diffuse Mutation Maximum Current Feeding Neurodevelopment Age presentation (years) Medication Medication method (years) dose dose
#1 5.3 Neonate 2.6 Diffuse Compound DZX 5 0 Orally Speech delay heterozygous mg/kg/d ABCC8
#2 9.3 Neonate 3.5 Diffuse Maternal DZX 10 0 Gastrostomy Speech delay KCNJ11 mg/kg/d (4 years)
#3 16.6 Neonate 13 Diffuse de novo DZX 7 0 Orally Normal ABCC8 mg/kg/d
#4 9.4 Neonate 0.7 Diffuse Maternal DZX 9.2 0 Orally Seizures at presentation, ABCC8 mg/kg/d behavioural problems
#5 4.3 Neonate 3.1 Diffuse Maternal DZX 7.1 0 Orally Normal ABCC8 mg/kg/d
#6 0.7 Neonate 0.4 Diffuse Paternal DZX 5 0 Orally Normal ABCC8 mg/kg/d
#7 6.7 Day 2 0.5 Diffuse Maternal DZX 5 0 Orally Epilepsy, motor delay, ABCC8 mg/kg/d coordination problems
#8 2.7 Day 2 0.2 Diffuse Maternal DZX 5 0 Orally Normal ABCC8 mg/kg/d
37
Patient Current Age at Resolved at Focal/Diffuse Mutation Maximum Current Feeding Neurodevelopment Age presentation (years) Medication Medication method (years) dose dose
#9 7.2 Day 1 6 Diffuse Homozygous OCT 18.5 0 Gastrostomy Normal ABCC8 mcg/kg/d; (2.5 years) Somatuline 60 mg 4-7 weekly
#10 2.7 Day 1 1.6 Focal Paternal OCT 15 0 Gastrostomy Normal KCNJ11 mcg/kg/d (1.3 years)
#11 10.9 8 months 6.6 Focal Paternal OCT 19 0 Orally Normal ABCC8 mcg/kg/d
#12 7.1 Day 1 7 Diffuse Compound OCT 14.5 0 Gastrostomy Normal heterozygous mcg/kg/d (3.6 years) ABCC8
#13 5.7 Day 1 1.9 Diffuse Paternal OCT 3.8 0 Gastrostomy Normal KCNJ11 mcg/kg/d (1.7 years)
#14 12.3 Day 1 9 Diffuse Homozygous OCT 19.2 0 Gastrostomy Mild gross motor, speech ABCC8 mcg/kg/d (1.2 years) delay
#15 7.6 Day 70 5.5 Diffuse Presumed OCT 17 0 Gastrostomy Normal paternal mcg/kg/d (2.0 years) KCNJ11
38
Patient Current Age at Resolved at Focal/Diffuse Mutation Maximum Current Feeding Neurodevelopment Age presentation (years) Medication Medication method (years) dose dose
#16 8.9 Day 5 Not resolved Diffuse Paternal DZX 10 DZX 6 Orally Epilepsy, speech, motor, KCNJ11 mg/kg/d mg/kg/d learning difficulties
#17 1.1 Day1 Not resolved Diffuse Homozygous DZX 10 DZX 0.5 Orally Normal ABCC8 mg/kg/d mg/kg/d
#18 1.3 Day 2 Not resolved Diffuse Paternal DZX 8.5 DZX 5.8 Orally Normal KCNJ11 mg/kg/d mg/kg/d
#19 5.1 Neonate Not resolved Diffuse de novo DZX 15 DZX 10.8 Gastrostomy Normal ABCC8 mg/kg/d mg/kg/d (continuing at present)
#20 6.8 Day 2 Not resolved Diffuse Maternal DZX 9.6 DZX 3.1 Orally Epilepsy, motor delay, ABCC8 mg/kg/d mg/kg/d behavioural problems
#21 3.2 Day 1 Not resolved Diffuse Paternal DZX 12.5 DZX 5 Gastrostomy Speech delay KCNJ11 mg/kg/d mg/kg/d (overnight only, continuing) Patients’ characteristics in this cohort of patients with medically treated KATP CHI (n=21), showing age at presentation, resolution status, diffuse/focal, medication dosage (DZX - diazoxide, OCT - octreotide), feeding practices and neurodevelopmental status. The type of genetic mutation (see also Table 3.2) has no correlation with resolution status of CHI. The mutation in patient #16 has been classified as a variant [8].
39 Table 3.2 Genetic characterisation of patients with medically treated KATP CHI
Patient Mutation Paternal Maternal de novo Reference
#1 Large deletion/ ABCC8 ABCC8 Deletion is novel , A355T reported in Missense p.? (c.(2258+1_2259- p.A355T (c.1063G>A) Ismail (2010) [24], Russo (2011) 1)_(2294+1_2295-1)del) [25], Snider (2013) [8], Mohnike (2014) [26]
#2 Missense KCNJ11 Arya (2014) [9], Shimomura (2009) p.T294M (c.881C>T) [27], Bellanne-Chantelot (2010) [28], Ilmaran (2010) [29], Gong (2015) [13]
#3 Missense ABCC8 Aguilar-Bryan (1999) [30] p.L508P (c.1523T>C)
#4 Missense ABCC8 Banerjee (2011) [10] p.T1516M (c.4547C>T)
#5 Missense ABCC8 Pinney (2008) [31], Park (2011) [32], p.R1539Q (c.4616G>A) Kapoor (2011) [33]
#6 Missense ABCC8 Arya (2014) [9], Christesen (2012) p.A1263T (c.3787G>A) [34]
#7 Missense ABCC8 Nestorowicz (1998) [35], Shyng p.G1382S (c.4144G>A) (1998) [36]
40
Patient Mutation Paternal Maternal de novo Reference
#8 Missense ABCC8 Banerjee (2011) [10] p.T1516M (c.4547C>T)
#9 Splicing/Splicing ABCC8 ABCC8 Powell (2011) [37] p.? (c.1467+5G>A) p.? (c.1467+5G>A)
#10 Missense KCNJ11 Snider (2013) [8] p.R34C (c.100C>T)
#11 Splicing ABCC8 Ohkubo (2005) [38], Suchi (2006) p.? (c.2041-21G>A) [39], Hardy (2007) [40], Mohnike (2014) [26], Lee (2015) [41]
#12 Missense/Nonsense ABCC8 ABCC8 G70R: Banerjee (2011) [10]; R842* : p.G70R (c.208G>A) p.R842* (c.2524G>T) Brunetti-Pierri (2008) [42], Mohnike (2014) [26]
#13 Missense KCNJ11 Suchi (2006) [39] p.G40D (c.119G>A)
#14 Splicing/Splicing ABCC8 ABCC8 Powell (2011) [37] p.? (c.1467+5G>A) p.? (c.1467+5G>A)
#15 Missense KCNJ11 Suchi (2006) [39] p.G40D (c.119G>A)*
#16 Missense KCNJ11 Coventry (2010) [43], Russo (2011) p.R195H (c.584G>A) [25], Snider (2013) [8]
41
Patient Mutation Paternal Maternal de novo Reference
#17 Missense/Missense ABCC8 ABCC8 Sogno Valin (2013) [21], Snider p.R526C (c.1576C>T) p.R526C (c.1576C>T) (2013) [8], Arya (2014) [44]
#18 Missense KCNJ11 Novel p.R206L (c.617G>T)
#19 Missense ABCC8 Pinney (2008) [31] p.I1512T (c.4535T>C)
#20 Missense ABCC8 Fernandez-Marmiesse (2006) [45], p.D310N (c.928G>A) Pinney (2008) [31]
#21 Missense KCNJ11 Bennett (2015) [46] p.R206C (c.616C>T) Genetic characterisation of patients with medically treated KATP CHI, showing gene defect, protein changes, type of mutation, mode of inheritance and citations (see references). *The p.G40D mutation is presumed to be of paternal origin. The mutation was not present in the sample from the mother and the father was unavailable for testing. The mutation in patient #16 has been classified in other publications as a variant of uncertain significance.
42 Case illustrations:
1. Patient #9 with a homozygous ABCC8 mutation and severe CHI at presentation was unresponsive to diazoxide. He was treated with octreotide via subcutaneous pump to a maximum dose of 18.5 mcg/kg/day and then switched to somatuline autogel 60 mg every 4 weeks subcutaneously. Monitoring at home showed normal glucose profiles, prompting somatuline injection intervals to be gradually increased from 4 to 7 weeks without recurrence of hypoglycaemia. However, the patient became increasingly intolerant of needles and injections, at which point his parents requested a trial period without medical therapy, adding
PUFA as a food supplement and monitoring carefully for relapse into hypoglycaemia. One year after stopping somatuline, this patient remains on PUFA as a food supplement in a dose 260 mg twice a day with satisfactory fasting tolerance, normal food frequency and regular daily activity including school.
2. Patient #10 with a previously reported paternal KCNJ11 missense mutation and 18- fluoro-dopa PET-CT scanning suggesting a lesion in the tail also had severe CHI at presentation. In the pre-operative period, euglycaemia was achieved with a combination of octreotide in a dose of 15 mcg/kg/day and gastrostomy feeding. At laparoscopic surgery, the lesion was not identified at the anatomical location suggested by imaging investigations. Her pancreatic tail biopsy showed normal histology, implying the presence of focal CHI elsewhere in the pancreas. Following discussion with parents, she was medically treated with octreotide. In follow up, octreotide was gradually decreased and then stopped at age 1.6 years with satisfactory fast tolerance. No recurrence of hypoglycaemia was observed in 1.1 years of follow-up after octreotide was discontinued.
Variation in natural history: tendency to resolution
Fourteen patients (67%) received diazoxide treatment with good treatment response. Seven
(33%) patients received SSRA treatment because they were either unresponsive or partially responsive to diazoxide (n=6) or developed adverse reactions to diazoxide (n=1). In follow up assessments, diazoxide dose was reduced in all patients [8.8 (5.0, 15.0) to 0.0 (0.0, 10.8) mg/kg/day (p<0.001 for difference)], Figure 3.1.
43
Figure 3.1 Maximum and present doses of diazoxide in children with CHI represented as box and whisker plots (median, 95% confidence intervals). In persistent CHI (CHI- Persistent), a higher maximal dose of diazoxide was required than in patients with resolved CHI (CHI-Resolved). Diazoxide dose was reduced both in CHI-Resolved and CHI-Persistent groups of patients.
Eight patients on diazoxide achieved resolution after a period of 1.6 (0.2, 13.0) years. Six patients on diazoxide did not achieve resolution and remained on treatment, although dose was reduced significantly [10.0 (8.5, 15.0) to 5.4 (0.5, 10.8) mg/kg/day, p=0.003] after a period of 4.1 (1.1, 8.9) years. In 7 patients who received SSRA treatment [maximum octreotide dose 17.0 (3.8, 19.2) mcg/kg/day], resolution was achieved in all. Resolution following SSRA treatment was noted in 2 patients (patients #11 and #15) who presented beyond the neonatal period. Patient #15 had diffuse CHI and was responsive to SSRA treatment, which was preferred in favour of sub-total pancreatectomy. In contrast, the diagnosis of focal CHI in patient #11 was delayed as initial genetic screening by Sanger sequencing of ABCC8 exons did not find a mutation. The paternal ABCC8 mutation was later
44 identified as a splice site mutation, Table 3.2, with focal CHI being confirmed by 18-fluoro- dopa PET-CT scanning. While focal lesionectomy was being planned, the patient’s medical management was reviewed; SSRA was stopped with satisfactory glucose measurements on a profile and a fast.
Resolution tended to be later in those receiving SSRA than in those receiving diazoxide [5.9
(1.6, 9.0) v 1.6 (0.2, 13.0) years of treatment, p=0.08]. Overall, CHI resolved in 15 (71%) children in this cohort at age 3.1 (0.2, 13.0) years with age appropriate fasts in hospital (16-
20 hours) demonstrating absence of hypoglycaemia, suppressed insulin secretion and robust ketotic responses, supplementary figures 3.A and 3.B, supported by satisfactory home glucose monitoring.
Factors associating with severity of illness were investigated for association with CHI resolution. GIR, a marker of severity of hypoglycaemia at presentation, was not significantly different in resolved CHI than in persistent CHI patients [14.9 (10.0, 18.5) v 16.5 (13.0, 20.0) mg/kg/min, p=0.6]. Maximum diazoxide dose was significantly less in resolved CHI than in persistent CHI patients [6.0 (5.0, 10.0) v 10.0 (8.5, 15.0), p=0.04]. Similar analysis was not performed in those on SSA, as resolution was achieved in all children.
Supplementary Figure 3.A Mean blood glucose levels (95% confidence intervals) before and after prolonged fasting in patients with resolved CHI.
45
Supplementary Figure 3.B Mean blood ketone (3 hydroxybutyrate) levels (95% confidence intervals) before and after prolonged fasting in patients with resolved CHI.
Neurodevelopmental outcomes:
Mild delayed development was observed in 8 (38%) children in one or more domains, Table
3.1. The proportion of children having developmental delay was not significantly different between those with resolved CHI and persistent CHI [5 (33%) v 3 (50%), p=0.5] and between those feeding orally and those requiring gastrostomy tube feeding [5 (42%) v 3
(33%), p=0.7]. GIR was similar between those with and without developmental delay [15.7
(13.0, 18.5) v 14.9 (10.0, 20.0), p=0.8]. Patients #9 and #17 with homozygous mutations and
#12 with a compound heterozygous mutation had normal developmental outcomes. However patient #14 who had a homozygous mutation had mild motor and speech delay.
VABS-II scores were available in 12 (57%) children older than 1.5 years of age, Figure 3.2.
VABS-II scores were within an acceptable population range at 0.3 (-1.7, +1.6) SDS, with trend towards higher scores (better adaptive functioning) in resolved compared with persistent CHI [-0.1 (-1.2, +1.6) v -1.2 (-1.7, +0.1), p=0.1] for most domains, but not reaching significance. Out of the VABS-II domains, daily living skills showed a significant difference with higher scores, i.e. a more favourable developmental outcome in resolved CHI compared to those with persistent CHI [-0.2 (-1.4, +0.6) v -1.6 (-2.0, -0.6), p=0.02].
46 Figure 3.2 - Vineland Adaptive Behavior Scales, 2nd edition (VABS-II) scores as standard deviation scores (SDS) for patients with persistent CHI (CHI-Persistent) and resolved CHI (CHI-Resolved). VABS-II scores as SDS represented as box and whisker plots (median, 95% confidence intervals). Total SDS scores representing the Adaptive Behavior Composite (ABC) are shown in white boxes while individual domains are depicted in colour.
Feeding outcomes:
Twelve (57%) children were fed orally without requirement for nasogastric or gastrostomy tube feeding, Table 3.1. In those with oral food refusal and aversion, gastrostomy tube feeding continued in part or full for a variable period ranging between 1.3 to 5.1 years.
Resolved CHI was similar in frequency between orally feeding and gastrostomy feeding children [8(67%) v 7(78%), p=0.6]. Abnormal development was also similar in frequency between orally- and gastrostomy-fed children [5(42%) v 3(33%), p=0.7].
47 3.6 Discussion
Our study of young patients with KATP CHI suggests that resolution of CHI occurs in a significant proportion (71%) of those safely managed by conservative medical treatment.
Resolution did not occur in all patients in prolonged follow up, but there is reduction in the intensity of treatment for hypoglycaemia, suggesting a trend of reducing severity of disease over time.
Our findings of reducing severity in both recessively or dominantly inherited ABCC8/KCNJ11 mutations extend the recognised theme that dominant mutations may be mild [19] and that resolution can occur in a proportion of patients with recessively inherited disease [11, 20].
Our findings are consistent with observations in large cohorts where patients with homozygous and compound heterozygous mutations may be medically managed without need for pancreatic surgery [7]. While it is recognised that the natural history of CHI may become clinically more manageable, our report provides objective and systematic evidence for this prevailing notion. Our findings also provide much needed prognostic information about the disease trajectory of KATP CHI and guidance for clinicians to re-evaluate severity at successive intervals and reduce medication as necessary.
Our study population is relatively small (n=21) and only five patients had compound heterozygous and homozygous mutations representing severe diffuse CHI. However, patient numbers are not small for a rare disease drawn from a relatively large group of patients with genetic and non-genetic CHI over a 10-year period. Replication in other international cohorts would be helpful to prove the strength of association. Larger cohorts and international databases would be required to determine factors associated with reduction in severity as the number of patients in our cohort were too few (n=7) to hypothesise mechanisms of disease resolution in CHI caused by recessively inherited mutations.
Only six children in this cohort remained on long-term medication. Two of these patients had missense mutations affecting KCNJ11 residue p.R206. Three other patients tested in Exeter had mutations at this residue and had congenital hyperinsulinism that persisted for between
21 months and >3 years. The ABCC8 p.R526C mutation was reported in a patient who required treatment up to the age of 6 years [21]. However, a genotype:phenotype correlation
48 is not absolute since the ABCC8 p.I1512T mutation was found in another patient tested in
Exeter whose hyperinsulinism remitted within a few days of birth.
In our study, we have provided genetic information on the type of KATP channel gene mutations in CHI patients. However, we have not investigated genotype predictions of natural history phenotype as in-silico predictions are unreliable in establishing pathogenicity and have not been tested in model predictions of disease trajectory. As experience in medical management of patients with KATP CHI accumulates worldwide, our study suggests the need to generate phenome databases to derive genotype-assisted prediction models of disease prognosis.
Although patients in our cohort had reducing severity, the neurodevelopmental phenotype was no different to previous cohorts [3, 5, 6]. This is likely to reflect adverse impact of hypoglycaemia in early life [3] and not likely to reflect the impact of continuing hypoglycaemia, as home glucose monitoring had been satisfactory in all patients. Further strength comes from the observation that the majority of the most severe patients, i.e. those with homozygous and compound heterozygous mutations had normal neurodevelopmental outcomes.
We did not observe deterioration in oral feeding with treatment reduction and disease resolution. The majority of children in this cohort were orally fed; those requiring gastrostomy tube feeding improved oral feeding over time. Therefore, treatment withdrawal or reduction was not associated with the collateral effect of increasing reliance on gastrostomy tube feeding.
Although we have reported a reduction in disease severity in the natural history and progression of genetic forms of CHI, we have been unable to find markers at presentation that could predict the resolution of disease. Therefore, it follows that CHI should be treated aggressively at the outset as recommended [1, 22], but with regular monitoring in follow-up to reduce treatment dosage, where feasible. The reduction in treatment intensity is not only a responsive management strategy, but also potentially reduces the significant harm to patients from excessive doses and prolonged exposure to medications with recognised toxic adverse effect profiles. We would recommend telephone and/or electronic communication
49 every 2 weeks for the first 4 months to understand trends in home glucose profiles and drug response, followed by 4 monthly clinic reviews to assess the need for dose reduction. We would also suggest annual review of therapy for those remaining on treatment for longer than a year. Although we did not find patients experiencing relapse of hypoglycaemia in the relatively short duration of follow up, we would suggest on-going monitoring for the risk of hypoglycaemia, particularly during illness episodes for at least two years.
One criticism to adopt a step down treatment approach is the exposure to the potential risk of hypoglycaemia. However, the frequency of adverse neurodevelopment in our cohort was no different in those between resolution and persistence of CHI and no different than previous cohorts [5, 6]. The frequency of adverse neurodevelopment in the medically treated group has not been compared directly with the frequency in patients treated surgically in our cohort, although comparison of our data with other cohorts suggests a similar prevalence [4].
If early onset hypoglycaemia is the most important determinant of later life adverse neurodevelopment [3], it is unlikely that the small risk of hypoglycaemia from a proposed reduction in therapeutic intensity would be more detrimental. Nonetheless, it would be advisable to weigh up risks and benefits when offering treatment de-escalation choices to parents of children with CHI.
In our study of natural history outcomes, we did not evaluate glucose tolerance as part of the assessment of glycaemic outcomes, unlike other studies following pancreatectomy [23].
However, the utility of glucose tolerance testing at a young age in patients with resolving CHI not requiring surgery has not been established. Nonetheless, it would be important to evaluate formal glucose tolerance in older children and adolescents with resolved CHI to investigate the probability of evolving hyperglycaemia and diabetes.
3.7 Conclusions
A reduction in severity of CHI was noted in all patients with KATP CHI, while a significant majority achieved hypoglycaemia resolution in follow up assessment, including those with compound heterozygous and homozygous mutations. Information about reducing severity could be discussed early in the management of CHI to guide prognosis and parental expectations. In children who are medically managed, disease severity should be
50 periodically reviewed to assess the need to reduce medication dosage in anticipation of disease resolution.
List of Abbreviations:
CHI: congenital hyperinsulinism, KATP CHI: congenital hyperinsulinism due to mutations in
KATP channel genes, SSRA: somatostatin receptor agonists, GIR: glucose infusion rate,
SDS: Standard Deviation Scores, PUFA: polyunsaturated fatty acids, EPA:
Eicosapentaenoic acid, CGM: continuous glucose monitoring, VABS-II: Vineland Adaptive
Behavior Scales, version II.
Declarations:
Ethics approval and consent to participate: This study was supported by The North
West Research Ethics Committee (project reference number: 07/H1010/88) to which
parents were consented to participate.
Consent for publication: Not applicable (no individual patient information disclosed).
Availability of data and material: All data generated or analysed during this study are
included in this published article in the format uploaded.
Competing interests: There are no competing interests.
Funding: The study received funding from the following sources: National Institute
for Health Research, Translational Research Collaboration, NORCHI Charitable
Fund, Research and Innovation supporting funds from Central Manchester
University Hospitals and University of Manchester and The Million Dollar Bike Fund.
SEF has a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the
Royal Society (Grant Number: 105636/Z/14/Z).
Authors' contributions: MSE, IB, and MJD were responsible for design and methods.
MSE, SEF, MJD, KEC, JN, IB authored the manuscript. SE, LR, LB, ZM, MS, CH,
RC, RP, NM and TR were involved in data collection, analysis and critical comments
51 on the writing of the manuscript. MSE and IB were responsible for statistical
analysis. All authors read and approved the final manuscript.
Acknowledgements: The authors are grateful to research nurses and clinical
colleagues at Central Manchester University Hospitals NHS Trust and the
Manchester Biomedical Research Centre.
3.8 References
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52 13. Gong C, Huang S, Su C, Qi Z, Liu F, Wu D, et al. Congenital hyperinsulinism in Chinese patients: 5-yr treatment outcome of 95 clinical cases with genetic analysis of 55 cases. Pediatr Diabetes. 2015;17(3):227-234. 14. Demirbilek H, Shah P, Arya VB, Hinchey L, Flanagan SE, Ellard S, Hussain K. Long- term follow-up of children with congenital hyperinsulinism on octreotide therapy. J Clin Endocrinol Metab. 2014;99(10):3660-3667. 15. Glaser B, Landaw H. Long-term treatment with the somatostatin analogue SMS 201- 995: alternative to pancreatectomy in persistent hyperinsulinaemic hypoglycaemia of infancy. Digestion. 1990;45 Suppl 1:27-35. 16. Skae M, Avatapalle HB, Banerjee I, Rigby L, Vail A, Foster P, et al. Reduced Glycemic Variability in Diazoxide-Responsive Children with Congenital Hyperinsulinism Using Supplemental Omega-3-Polyunsaturated Fatty Acids; A Pilot Trial with MaxEPA(R.). Front Endocrinol (Lausanne). 2014;5:31. 17. Han B, Newbould M, Batra G, Cheesman E, Craigie RJ, Mohamed Z, et al. Enhanced Islet Cell Nucleomegaly Defines Diffuse Congenital Hyperinsulinism in Infancy but Not Other Forms of the Disease. Am J Clin Pathol. 2016;145(6):757-768. 18. Freeman JV, Cole TJ, Chinn S, Jones PR, White EM, Preece MA. Cross sectional stature and weight reference curves for the UK, 1990. Arch Dis Child. 1995;73(1):17- 24. 19. Huopio H, Reimann F, Ashfield R, Komulainen J, Lenko HL, Rahier J, et al. Dominantly inherited hyperinsulinism caused by a mutation in the sulfonylurea receptor type 1. J Clin Invest. 2000;106(7):897-906. 20. Yorifuji T, Hosokawa Y, Fujimaru R, Kawakita R, Doi H, Matsumoto T, et al. Lasting 18F-DOPA PET uptake after clinical remission of the focal form of congenital hyperinsulinism. Horm Res Paediatr. 2011;76(4):286-290. 21. Sogno Valin P, Proverbio MC, Diceglie C, Gessi A, di Candia S, Mariani B, et al. Genetic analysis of Italian patients with congenital hyperinsulinism of infancy. Horm Res Paediatr. 2013;79:236-242. 22. De Leon DD, Stanley CA. Mechanisms of Disease: advances in diagnosis and treatment of hyperinsulinism in neonates. Nat Clin Pract Endocrinol Metab. 2007;3(1):57-68. 23. Beltrand J, Caquard M, Arnoux JB, Laborde K, Velho G, Verkarre V, et al. Glucose metabolism in 105 children and adolescents after pancreatectomy for congenital hyperinsulinism. Diabetes Care. 2012;35(2):198-203. 24. Ismail D, Smith VV, de Lonlay P, Ribeiro MJ, Rahier J, Blankenstein O, et al. Familial focal congenital hyperinsulinism. J Clin Endocrinol Metab. 2010;96(1):24-28. 25. Russo L, Iafusco D, Brescianini S, Nocerino V, Bizzarri C, Toni S, et al. Permanent diabetes during the first year of life: multiple gene screening in 54 patients. Diabetologia. 2011; 54(7):1693-1701. 26. Mohnike K, Wieland I, Barthlen W, Vogelgesang S, Empting S, Mohnike W, et al. Clinical and genetic evaluation of patients with KATP channel mutations from the German registry for congenital hyperinsulinism. Horm Res Paediatr. 2014;81(3):156- 168. 27. Shimomura K, Flanagan SE, Zadek B, Lethby M, Zubcevic L, Girard CA, et al. Adjacent mutations in the gating loop of Kir6.2 produce neonatal diabetes and hyperinsulinism. EMBO Mol Med. 2009;1(3):166-177. 28. Bellanne-Chantelot C, Saint-Martin C, Ribeiro MJ, Vaury C, Verkarre V, Arnoux JB, et al. ABCC8 and KCNJ11 molecular spectrum of 109 patients with diazoxide- unresponsive congenital hyperinsulinism. J Med Genet. 2010;47(11):752-759. 29. Ilamaran V, Venkatesh C, Manish K, Adhisivam B. Persistent hyperinsulinemic hypoglycemia of infancy due to homozygous KCNJ11 (T294M) mutation. Indian J Pediatr. 2010;77(7):803-804.
53 30. Aguilar-Bryan L, Bryan J. Molecular biology of adenosine triphosphate-sensitive potassium channels. Endocr Rev. 1999;20(2):101-135. 31. Pinney SE, MacMullen C, Becker S, Lin YW, Hanna C, Thornton P, et al. Clinical characteristics and biochemical mechanisms of congenital hyperinsulinism associated with dominant KATP channel mutations. J Clin Invest. 2008;118(8):2877- 2886. 32. Park SE, Flanagan SE, Hussain K, Ellard S, Shin CH, Yang SW. Characterization of ABCC8 and KCNJ11 gene mutations and phenotypes in Korean patients with congenital hyperinsulinism. Eur J Endocrinol. 2011;164(6):919-926. 33. Kapoor RR, Flanagan SE, James CT, McKiernan J, Thomas AM, Harmer SC, et al. Hyperinsulinaemic hypoglycaemia and diabetes mellitus due to dominant ABCC8/KCNJ11 mutations. Diabetologia. 2011;54(10):2575-2583. 34. Christesen HT, Brusgaard K, Hussain K. Recurrent spontaneous hypoglycaemia causes loss of neurogenic and neuroglycopaenic signs in infants with congenital hyperinsulinism. Clin Endocrinol (Oxf). 2012;76(4):548-554. 35. Nestorowicz A, Glaser B, Wilson BA, Shyng SL, Nichols CG, Stanley CA, et al. Genetic heterogeneity in familial hyperinsulinism. Hum Mol Genet. 1998;7(7):1119- 1128. 36. Shyng SL, Ferrigni T, Shepard JB, Nestorowicz A, Glaser B, Permutt MA, Nichols CG. Functional analyses of novel mutations in the sulfonylurea receptor 1 associated with persistent hyperinsulinemic hypoglycemia of infancy. Diabetes. 1998;47(7):1145-1151. 37. Powell PD, Bellanne-Chantelot C, Flanagan SE, Ellard S, Rooman R, Hussain K, et al. In vitro recovery of ATP-sensitive potassium channels in beta-cells from patients with congenital hyperinsulinism of infancy. Diabetes. 2011;60(4):1223-1228. 38. Ohkubo K, Nagashima M, Naito Y, Taguchi T, Suita S, Okamoto N, et al. Genotypes of the pancreatic beta-cell KATP channel and clinical phenotypes of Japanese patients with persistent hyperinsulinaemic hypoglycaemia of infancy. Clin Endocrinol (Oxf). 2005; 62(4):458-465. 39. Suchi M, MacMullen CM, Thornton PS, Adzick NS, Ganguly A, Ruchelli ED, Stanley CA. Molecular and immunohistochemical analyses of the focal form of congenital hyperinsulinism. Mod Pathol. 2006;19(1):122-129. 40. Hardy OT, Hernandez-Pampaloni M, Saffer JR, Suchi M, Ruchelli E, Zhuang H, et al. Diagnosis and localization of focal congenital hyperinsulinism by 18F-fluorodopa PET scan. J Pediatr. 2007;150(2):140-145. 41. Lee BH, Lee J, Kim JM, Kang M, Kim GH, Choi JH, et al. Three novel pathogenic mutations in KATP channel genes and somatic imprinting alterations of the 11p15 region in pancreatic tissue in patients with congenital hyperinsulinism. Horm Res Paediatr. 2015; 83(3):204-210. 42. Brunetti-Pierri N, Olutoye OO, Heptulla R, Tatevian N. Case report: pathological features of aberrant pancreatic development in congenital hyperinsulinism due to ABCC8 mutations. Ann Clin Lab Sci. 2008;38(4):386-389. 43. Coventry A, Bull-Otterson LM, Liu X, Clark AG, Maxwell TJ, Crosby J, et al. Deep resequencing reveals excess rare recent variants consistent with explosive population growth. Nat Commun. 2010;1:131. 44. Arya VB, Aziz Q, Nessa A, Tinker A, Hussain K. Congenital hyperinsulinism: clinical and molecular characterisation of compound heterozygous ABCC8 mutation responsive to Diazoxide therapy. Int J Pediatr Endocrinol. 2014;2014(1):24. 45. Fernandez-Marmiesse A, Salas A, Vega A, Fernandez-Lorenzo JR, Barreiro J, Carracedo A. Mutation spectra of ABCC8 gene in Spanish patients with Hyperinsulinism of Infancy (HI). Hum Mutat. 2006;27(2):214.
54 46. Bennett JT, Vasta V, Zhang M, Narayanan J, Gerrits P, Hahn SH. Molecular genetic testing of patients with monogenic diabetes and hyperinsulinism. Mol Genet Metab. 2015; 114(3):451-458.
55 CHAPTER 4 mTOR Inhibitors for the Treatment of Severe Congenital Hyperinsulinism:
Perspectives on Limited Therapeutic Success
Marie Szymanowski1, Maria Salomon Estebanez2, Raja Padidela2, Bing Han3, Karolina
Mosinska3, Adam Stevens3, Lena Damaj4, Florence Pihan-Le Bars4, Emilie
Lascouts4, Rachel Reynaud5, Catherine Ferreira5, Claire Bansept6, Pascale de
Lonlay6,7,8, Cécile Saint-Martin9, Mark J. Dunne3, Indraneel Banerjee2, Jean-Baptiste
Arnoux6.
1. Department of Paediatrics, Centre Hospitalier Universitaire Estaing, 63003 Clermont-Ferrand Cedex 1, France. 2. Department of Paediatric Endocrinology, Royal Manchester Children’s Hospital, Manchester M13 9WL, United Kingdom. 3. Faculty of Life Science, University of Manchester, Manchester M13 9PL, United Kingdom. 4. Department of Paediatrics, Sud Hospital, 35203 Rennes, France; 5. Department of Paediatrics, Timone Hospital, 13385 Marseille Cedex 5, France; 6. Metabolism Unit, Necker-Enfants Malades Hospital, Assistance Publique-Hôpitaux de Paris, 75743 Paris Cedex 15, France; 7. Imagine-Genetic Disease Institute, 75015 Paris, France; 8. Paris Descartes University, 75270 Paris, France; 9. Department of Genetics, Assistance Publique-Hôpitaux de Paris Groupe Hospitalier Pitié-Salpêtrière, Pierre et Marie Curie University, 75013 Paris Cedex 13, France
This chapter is a modified version of the publication in JCEM and only includes data from the four UK patients. It was published in J Clin Endocrinol Metab. 2016 Dec;101(12):4719-4729.
DOI: 10.1210/jc.2016-2711
56 4.1 Abstract
Introduction: Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycaemia in neonates and infants. In medically unresponsive CHI, subtotal pancreatectomy is performed to achieve euglycaemia with consequent diabetes in later life.
Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been reported to obviate the need for pancreatectomy, but experience is limited.
Methods: Patients with CHI unresponsive to medical treatment were recruited. Sirolimus efficacy was ascertained by cessation of intravenous dextrose and achievement of adequate fasting tolerance with sustainable euglycaemia. Patients were monitored for drug efficacy and side effects; treatment was withdrawn if persistent hypoglycaemia or serious side effects occurred. Post-operative examination of pancreatic tissue was used to assess rates of cell proliferation using Ki67 expression.
Results: Four patients with severe CHI were included. Sirolimus was effective in one patient with euglycaemia sustained following discharge from hospital. Two patients showed an initial response; however, treatment effect was reversed with increasing hypoglycaemia. In one patient, no response was observed. One patient had stomatitis, two patients developed exocrine pancreatic insufficiency and two patients had sepsis. Subtotal pancreatectomy was performed in 3 patients. Pancreatic tissue from two patients who did not respond to sirolimus showed no reduction in cell proliferation, further suggesting that mTOR signalling did not down-regulate proliferation in the CHI pancreas.
Conclusion: mTOR inhibitor treatment is associated with very limited success and must be used with caution in children with severe CHI.
57 4.2 Background
Congenital hyperinsulinism (CHI), the major cause of persistent hypoglycaemia in neonates and infants, is the consequence of a dysfunction in pancreatic β-cells. Excess and inappropriate insulin secretion can lead to recurrent hypoglycaemia, causing severe and permanent brain damage. A significant proportion, as high as 44% of patients with CHI, develop learning disability and mental retardation [1-3]. Therefore, prompt and early treatment of hypoglycaemia is very important for the neurological prognosis of patients with
CHI [4]. Diazoxide-unresponsive CHI has a genetic basis in 91% - 98% of patients manifested as diffuse or focal forms, respectively [3]. Fluorine-18-dihydrophenylalanine (18F-
DOPA) positron emission tomography (PET) [5, 6] is undertaken to identify and localise focal
CHI, particularly in those carrying paternal heterozygous mutations in ABCC8/KCNJ11. The therapeutic strategy is different between the diffuse and focal forms. Whereas focal CHI can be cured by selective and partial pancreatectomy, the management of diazoxide- unresponsive diffuse CHI is more challenging. Diffuse CHI can be unresponsive to optimal medical treatment (diazoxide and/or octreotide) and may require subtotal pancreatectomy to achieve euglycaemia. However, despite surgery, 40% - 59% of operated patients still continue to experience persistent hyperinsulinaemic hypoglycaemia for months or years [1,
7], and 98% will develop diabetes mellitus within 14 years after the surgery [7]. Therefore, medical treatment alternatives should be considered in preference to surgery in diffuse and severe CHI. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been recently reported to be useful in the treatment of severe diffuse CHI, with no major adverse events in a limited number of patients [8]. Constitutive activation of the mTOR pathway has been postulated as a mechanism for hyperinsulinism and β-cell hyperplasia in diffuse CHI [8,
9], although this has not been substantiated in CHI pancreatic tissue. The inhibition of the mTOR pathway is known to be effective in the treatment of some cancers through inhibition of growth factors and cellular proliferation [10–14]. mTOR inhibitors have been shown to be effective in inhibiting insulin production in patients with insulinomas [15]. Two mTOR inhibitors are commercially available: sirolimus and everolimus. Although effective, mTOR inhibitor use can be complicated by adverse events [17–20], which may limit their applications in neonates and infants with severe CHI. The efficacy and safety profile of
58 mTOR inhibitors have not been widely reported in the treatment of young children with CHI.
Here we aim to review the efficacy and safety of mTOR inhibitors in the treatment of patients with severe CHI.
4.3 Methods
Patients
Four patients with severe diffuse CHI who were unresponsive to maximal medical treatment
(diazoxide and/or somatostatin analog) were recruited with informed consent between June
2014 and June 2016 to take part in an observational cohort study under protocol, after permission from institutional review boards. The eligibility criteria for recruitment to this study were as follows: patients with CHI older than 2 weeks with persistent and severe CHI with or without mutations in ABCC8/KCNJ11 and unresponsive to large oral dose of diazoxide (15 mg/kg/day) and subcutaneous or intravenous octreotide (20 micrograms/kg/day). The use of glucagon and variations in nutritional intake to stabilise glucose profiles were permitted.
Patients with suspected or confirmed focal CHI, who would be eligible for surgical lesionectomy, and those with stable glycaemic profiles on diazoxide and octreotide were excluded from recruitment.
Patients were continued on sirolimus if the following criteria were met: 1) glycaemic control was achieved (>3.5 mmol/L for > 90% of measurements) over a 48-hour period without requirement for iv fluids or glucagon therapy; 2) patients were able to tolerate oral or gastrostomy enteral nutrition and were able to fast for a significantly longer period than at baseline; and 3) there were no serious adverse events from sirolimus.
The use of additional CHI medication, either diazoxide or octreotide was permitted if one or both medications were tolerated by the patient. In contrast, if patients developed serious adverse events from sirolimus treatment or success criteria were not achieved by 6 weeks of therapy, sirolimus was discontinued.
Four patients from the Paediatric Endocrinology Department of the Royal Manchester
Children’s Hospital were recruited for the study. The characteristics of the patients are shown in Table 4.1.
59 Table 4.1 Patients’ characteristics and glycaemic support before mTOR inhibitors
Patients’ characteristics
Patients Sex Gestational Birth Genetic Age at age weight characteristics diagnosis weeks grams (centile) 1 Female 36 2.550 No mutation in ABCC8, 13 months (50) KCNJ11, GCK, HADH, GLUD1, HNF4A
2 Female 39 3.400 2 homozygous 1 day (75) mutations in ABCC8
1 maternally inherited: p.? (c.148+1G>A)
1 paternally inherited: p.? (c.148+1G>A)
3 Female 33 2.160 2 homozygous 1 day (75) mutations in ABCC8
1 maternally inherited: p.? (c.1467+5G>A)
1 paternally inherited: p.? (c.1467+5G>A)
4 Female 37 3.820 2 homozygous 1 day (99) mutations in ABCC8
1 maternally inherited: p.Glu786del (c.2356_2358del)
1 paternally inherited: p.Glu786del (c.2356_2358del)
Patients were between 1 and 14 months old at the initiation of mTOR inhibitor treatment. All patients had severe CHI diagnosed between birth and 13 months. One child presented with seizures (patient number 4). All had excessive insulin secretion at the time of hypoglycaemia. Three patients (patients numbers 2-4) were born to consanguineous parents. All patients were unresponsive to medical treatment and required intravenous
60 glucose as well as enteral feeds with high-carbohydrate content. One patient required continuous glucagon infusion to achieve euglycaemia. All patients had minimal fasting tolerance prior to sirolimus treatment. Medical therapy and supporting glucose requirements at study entry are shown in Table 4.2. 18F-DOPA PET scanning was performed in patient number 1 and excluded focal CHI. The other children in this cohort had genetic aetiology consistent with diffuse CHI, whereby a 18F-DOPA PET scan was not required.
Table 4.2 Medical therapy and supporting glucose requirement at study entry
Patients DZX OCT Glucagon GIRa IV Enteral Duration mg/kg/d µg/kg/d µg/kg/h mg/kg/ fluids feeding of fasting min mg/kg/ mg/kg/min before min mTOR inhibitor 1 - 11 - 7.5 7.5 Solids < 1h
2 - 20 7.5 10.6 2.2 8.4 < 1h
3 - 20 - 16.7 13.3 3.4 < 1h
4 - 20 - 15.9 6.6 9.3 < 1h
DZX: Diazoxide, OCT: Octreotide, IV: intravenous aGlucose infusion rate (GIR) was calculated from glucose content in infusion fluids and milk feeds. Additional glucose in solid food was not counted.
Genetic basis of CHI and cell proliferation
Genomic DNA was extracted by standard methods. The coding regions and conserved splice site of ABCC8 (NM_001287174.1) and KCNJ11 (NM_000525.3) genes were amplified by PCR assay and sequenced as per protocol as previously reported [21]. Diffuse CHI was diagnosed on the basis of 18F-DOPA PET scanning, homozygous mutations in ABCC8 gene and standard histopathological criteria [3, 22, 23]. Pancreatic proliferation was assessed by immunostaining with Ki67 and high content analysis in pancreatic tissue (n = 18 053–30 144 cells) and islets (n = 2863–4171 cells) in two patients after surgery using methods previously described [24]. For comparative purpose we also include data from three age-matched control pancreas and five CHI tissues from patients not receiving sirolimus therapy [24].
61 Treatment
Patients received sirolimus at an initial dose of 0.5–1 mg/m2 of body surface area per day
(milligrams per square meter per day) between ages 1 and 14 months. Sirolimus
(Rapamune; Pfizer) was given as syrup in a concentration of 1 mg/mL. Medication dosage was gradually increased with the goal of reaching a serum trough level (measured 5 days after each change in dosage) of 5-15 ng/mL. Once serum trough levels were achieved, intravenous glucose was weaned to achieve euglycaemia with enteral nutrition only. Other medications were also weaned to a point at which euglycaemia could be maintained safely.
Patients were then tested for fasting tolerance. This was conducted as per institutional protocol for 6 hours to test whether euglycaemia (>3.5 mmol/L) was maintained and whether ketogenesis was achieved. Patients were regularly monitored for blood counts, fasting lipid profile, glucose profile, and serum mTOR inhibitor trough levels as described in table 4.5.
Patients were assessed daily for adverse events during in-patient stay and monthly during outpatient monitoring. All studies were carried out in accordance with ethical approval, national codes of practice, and informed consent.
4.4 Results
Treatment with sirolimus: response and outcomes
Sirolimus was given at a maximum dose at 2.3 mg/m2/day for a period ranging between 1 and 9 months. Sirolimus trough levels exceeded the expected upper limit (15 ng/mL) in three patients, Table 4.3; one patient (patient 2) required a blood transfusion (haemoglobin 7.2 g/dL). Sirolimus was discontinued because of its ineffectiveness in achieving euglycaemia in three patients. The glycaemic responses to mTOR inhibitor treatment are shown in Table
4.4. Sirolimus was beneficial partially or wholly in three patients (patients 2-4), in whom an increased duration of fasting was evidenced. In patient 3 intravenous dextrose was discontinued and fasting tolerance was increased to 4 hours after 1 month of treatment.
Initial glycaemic improvement was observed in patients 2 and 4; glucagon was discontinued in patient 2 and intravenous fluid therapy was discontinued in patient 4. However, both patients relapsed into recurrent hypoglycaemia despite sirolimus levels being in the therapeutic range. Patient 1 did not respond to sirolimus at all and did not achieve safe and
62 sustainable euglycaemia for home management. Patients 1, 2, and 4 underwent subtotal pancreatectomy to improve glucose profiles after 1, 1.5, and 3 months of sirolimus therapy, respectively. Patient 1 remained euglycaemic (fast tolerance 8 h) 1.5 years after surgery with no requirement for pancreatic exocrine supplements. Patient 2 also remained euglycaemic
(fast tolerance 6 h) 1 year after surgery with occasional hypoglycaemia during illness episodes. She continued to have pancreatic exocrine insufficiency and required supplements with main meals. Patient 4 had also undergone subtotal pancreatectomy after the failure of sirolimus therapy and was euglycaemic after surgery. Three weeks after discontinuing sirolimus treatment, she developed severe central venous catheter sepsis and pulmonary consolidation requiring intensive care support with conventional and oscillatory ventilation and inotropic support. In patient 3 there was a loss of treatment response after 9 months of treatment. Sirolimus was stopped prior to gastrostomy insertion and the glucose profile remained stable on the previous dose of octreotide and off sirolimus. She remained clinically stable on four times daily Octreotide injections and has not required subtotal pancreatectomy.
Therefore, in this group of patients with severe CHI, mTOR inhibitors were clinically useful in only one patient (25%).
Table 4.3 mTOR inhibitor treatment, dose, trough levels and duration of treatment
mTOR inhibitor treatment
Patients mTOR inhibitor Age at Start Maximal Trough level Duration of (months) dosage µg/l (mean) treatment (mg/m2/d) (months)
9.1 – 11.5 1 Sirolimus 14 1 1 (10.3)
3.2 – 16.5 2 Sirolimus 1 2.3 3 (8.9) 7 – 19 3 Sirolimus 1 1.4 (14.1) 9
8.7 – 15.3 4 Sirolimus 1 1.2 1 (11.2)
63 Table 4.4 Response to treatment, duration of fasting and clinical adverse events
Patients Response to treatment Duration of fast Adverse with mTOR events inhibitors treatment
1 None; subtotal pancreatectomy <1h Stomatitis, rash, diarrhoea, sepsis
2 Day 12: discontinuation of glucagon 4h Gut Week 3: discontinuation of IV fluids dysmotility, Week 5: increased fasting tolerance to 4 EPI hours Month 3: recurrent hypoglycaemia; subtotal pancreatectomy
3 Month 1: discontinuation of IV fluids + 4h Gut increased fasting tolerance to 4 hours dysmotility, Month 9: loss of treatment response, EPI sirolimus stopped
4 Day 15: discontinuation of IV fluids + 3h Sepsis increased fasting tolerance to 3 hours Week 4: recurrent hypoglycaemia; subtotal pancreatectomy EPI: exocrine pancreatic insufficiency assessed by low levels of faecal elastase. IV: intravenous
Adverse events from treatment with mTOR inhibitors
For a cumulative period of 14 months and a longest duration of 9 months of treatment, adverse events are shown in Table 4.4. Although no serious adverse events were reported, two children (patients 1 and 4) had septicaemia with infection in the central venous catheter for which sirolimus treatment was interrupted and eventually stopped. In three patients
(patients 1–3), bowel disturbances were noted. These included recurrent diarrhea and vomiting illnesses that were chronologically associated with sirolimus treatment and pancreatic exocrine insufficiency characterised by low faecal elastase levels prior to pancreatectomy. One patient had stomatitis.
64 Monitoring data show that three patients had mild neutropaenia and one had severe anaemia, Table 4.5. Cholesterol levels were normal and one patient had moderately high pre-feed triglyceride levels. In one patient, the lipid profile was not assessed, but treatment was discontinued.
Table 4.5 Monitoring data in follow-up assessments after mTOR inhibitor treatment
Patients WBC Neutrophils Hb Platelets Cholesterol TG 9 9 9 x10 /L x10 /L g/dl x10 /L mmol/l mmol/l (mean) (mean) (mean) (mean) (mean) (mean)
1 5.1 - 13 1.3 - 8.1 8.5 - 11.0 191 - 336 _ _ (7.23) (2.6) (9.4) (271)
2 4.4 - 10.5 0.8 - 5.1 7.2 - 11.5 353 - 737 3.1 - 3.9 0.8 - 2.7 (7.4) (2.3) (9.1) (455) (3.64) (1.73)
3 5.7 - 11 0.7 - 2 8.8 - 12 252 - 570 1.9 - 2.9 0.5 - 0.7 (7.5) (1.2) (8.7) (344) (2.46) (0.56)
4 13.3 - 21 1.6 - 4.4 9.5 - 10.7 409 - 637 2.1 - 2.9 1.1 - 1.5 (16.7) (2.3) (10.2) (500) (2.5) (1.4)
– indicates none. WBC: White Blood Cells. Hb: Haemoglobin. TG: Triglycerides
Association of mTOR signaling with proliferation in CHI
CHI-induced proliferation after treatment with sirolimus
We used pancreatic tissue from two children (patient 1 and 2) to investigate the impact of continuous sirolimus treatment on the proliferative capacity of CHI pancreas, as shown in
Figure 4.1. The incidence of cell proliferation is enhanced in diffuse CHI and remained high with no reduction after mTOR inhibitor treatment in the pancreas and islets, Figures 4.1 and
4.2. For patients 1 and 2, on average 6.57% of the pancreatic cells were proliferative compared with 2.81% ± 1.55% (mean ± SEM, n = 3 cases) of age-matched controls (n = 3 cases) and 6.4% ± 0.75% in CHI tissue not treated with sirolimus (n = 5 cases) [24], Figure
4.2. The incidence of proliferation in islet cells for patients 1 and 2 was on average1.81% compared with 1% ± 0.28% in control (n = 3) and 1.65% ± 0.23% in CHI tissue not treated with sirolimus (n = 5), Figure 4.2.
65 Figure 4.1 Cell proliferation is not suppressed by sirolimus treatment.
A, Ki67+ cells (arrowhead) were used to assess proliferation in the age-matched control (4 months) and the pancreas of patient 2. The higher incidence of proliferating cells in CHI tissue was approximately 3-fold higher than controls.
B, A Comparison between the extent of Ki67+ cells (arrowheads) in the control (10 months) and the pancreas of patient 1. In the control tissue, there were significantly fewer proliferating cells at 10 months compared with 4 months (panel A). However, in the CHI tissue, the rates of proliferation were 7-fold higher and too numerous to indicate by arrowheads.
C and D, Data from the control and patient 1, which indicate that islet cell proliferation is not suppressed by sirolimus treatment. Scale bar (A), 200 µm; B, 100 µm; C, 50 µm.
66 Figure 4.2 Quantification of proliferation in CHI tissue following sirolimus
Rates of cell proliferation (fraction of Ki67+ cells) normalised to age-matched control tissue, n=3 cases. Whole pancreas and islet data for patients #1 and #2 have been averaged. Data from age-matched CHI tissues not treated by sirolimus have also been included, n=5. Note how sirolimus treatment has no major impact upon the enhanced rates of proliferation in the pancreas or islets in CHI tissue.
4.5 Discussion
The achievement of euglycaemia is challenging in patients with severe CHI, who are unresponsive to complex medical treatment. Whereas subtotal pancreatectomy remains the procedure of choice after the failure of medical therapy, surgery is not completely curative and could still be associated with unsatisfactory neurodevelopmental outcomes. Therefore, there is a need for alternative treatments minimising the requirement for irreversible pancreatic surgery, and the burden of demanding medical and nutritional intervention in severe CHI. Although sirolimus has been reported as successful in the management of four patients [8] and in sporadic case reports [25-29], there have been no systematic prospective studies of success/failure in cohorts of patients treated with mTOR inhibitors. Here we have described 4 patients treated in one specialised centre in which treatment success has been
67 modest. Whereas observational reports [8, 25, 27, 28] suggest satisfactory response to sirolimus and no adverse events, our experience suggests that drug response is only partial and has to be carefully considered for off-label prescribing. Our report provides a balanced perspective on the success of treatment with powerful immunosuppressant with potential harmful adverse events in young children.
We have strengthened our clinical observations with pancreatic tissue proliferation analysis to investigate the hypothesis that mTOR down-regulates the pathways of proliferation in the
CHI pancreas. We have demonstrated that, in keeping with non response to sirolimus, proliferation remains high after treatment with sirolimus. However, one caveat in the analysis of pancreatic proliferation is that pancreatic tissue was not available in those with a response to sirolimus and that tissue analysis was not performed immediately after discontinuing sirolimus treatment. The experience clearly shows that treatment with mTOR inhibitors is ineffective in most of the patients and is accompanied by frequent adverse events [26, 30].
Sirolimus is known to be a drug with a serious adverse event profile in older children and adults with no safety data in younger children, particularly neonates. Indeed, in one case report, sirolimus therapy achieved euglycaemia but was complicated by life-threatening adverse events including sepsis and renal and hepatic failure, leading to the cessation of treatment [26]. Long-term treatment with sirolimus has also been described to cause glucose intolerance by up-regulating hepatic gluconeogenesis, at the cost of excess lipid deposition in fatty tissues characterised by increasing levels of triglycerides and nonesterified fatty acid levels [31]. The effects of long-term hepatic fatty changes at a young age remain to be evaluated but could be potentially detrimental to health.
In the original series of patients treated with sirolimus [8], one child with a homozygous mutation in a KATP channel gene responded to sirolimus but required additional octreotide treatment and dependence on gastrostomy feeding. In our cohort, three patients treated with sirolimus had homozygous mutations in ABCC8; in two patients treatment effect was partial, whereas in the other child, treatment was effective to achieve euglycaemia. From our cohort it is not possible to identify which factors are associated with a greater probability of treatment success. Patient 1 without known mutations in ABCC8/ KCNJ11 also did not show
68 a response, implying that mutation status in KATP channel genes might impact on the severity of CHI but may not predict response to sirolimus treatment. Chronic insulin resistance has been observed after the use of mTOR inhibitors in the prevention of renal graft rejection [32].
Sirolimus is also associated with an increased risk of new-onset diabetes mellitus after transplantation [33]. In those studies reporting successful treatment in severe hyperinsulism, the mechanism of action of sirolimus is proposed to involve a reduction in islet cell proliferation [27]. This was supported by genomic data sets implicating the IGF-1/mTOR/Akt pathway with the pathophysiology of CHI [9]. By contrast, we found no evidence for a reduction in either endocrine or exocrine cell proliferation in patients treated with sirolimus up to the point of surgery, Figure 4.2. A role for the IGF-1 receptor/mTORC2/Akt pathway in CHI is also questionable. In the study of Senniappan et al [9], CHI gene expression profiles were found to be enriched for proliferation and expansion, but this is not surprising because formalin-fixed neonatal tissue was compared with adult pancreas (age 29 and 33 years).
4.6 Conclusion mTOR inhibitor treatment in severe diffuse CHI is successful only in a minority of patients and must be used cautiously in CHI specialised centres as adverse events are frequent. The mechanism of action of mTOR inhibition in reducing insulin secretion is not clear in CHI but is unlikely to involve a decrease in islet cell proliferation.
List of Abreviations
CHI: congenital hyperinsulinism, mTOR: mammalian target of rapamycin, 18F-DOPA PET:
Fluorine-18-dihydrophenylalanine positron emission tomography, DZX: Diazoxide, OCT:
Octreotide, IV: intravenous, GIR: glucose infusion rate, EPI: exocrine pancreatic insufficiency, WBC: White Blood Cells, Hb: Haemoglobin, TG: Triglycerides, SEM: standard error of mean.
69 Declarations
Ethics approval and consent to participate: This study was supported by The North
West Research Ethics Committee (project reference number: 07/H1010/88) to which
parents were consented to participate.
Consent for publication: Not applicable (no individual patient information disclosed).
Availability of data and material: All data generated or analysed during this study are
included in this published article in the format uploaded.
Competing interests: There are no competing interests.
Funding: The study received funding from the following sources: National Institute
for Health Research, Translational Research Collaboration, NORCHI Charitable
Fund, Research and Innovation supporting funds from Central Manchester
University Hospitals and University of Manchester and The Million Dollar Bike Fund.
Authors' contributions: MSE collected data (UK patients), analysed and interpreted
the results in conjunction with IB and MJD. BH and MJD performed cell proliferation
studies in pancreatic tissue. MSE contributed to writing the manuscript in
collaboration with MS, MJD, IB and JBA. LP, FPLB, EL, RR, CF, CB, PdL, CSM
were involved in data collection (French patients) and provided critical comments to
the manuscript. All authors read and approved the final manuscript.
Acknowledgments: We are grateful to the research nurses and clinical colleagues at
Central Manchester University Hospitals National Health Service Trust and the
Manchester Biomedical Research Centre.
4.7 References
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71 21. Banerjee I, Skae M, Flanagan SE, Rigby L, Patel L, Didi M, et al. The contribution of rapid KATP channel gene mutation analysis to the clinical management of children with congenital hyperinsulinism. Eur J Endocrinol. 2011;164(5):733-740. 22. Sempoux C, Capito C, Bellanné-Chantelot C, et al. Morphological mosaicism of the pancreatic islets: a novel anatomopathological form of persistent hyperinsulinemic hypoglycemia of infancy. J Clin Endocrinol Metab. 2011;96:3785-3793. 23. Rahier J, Guiot Y, Sempoux C. Morphologic analysis of focal and diffuse forms of congenital hyperinsulinism. Semin Pediatr Surg. 2011;20:3-12. 24. Salisbury RJ, Han B, Jennings RE, et al. Altered phenotype of β-cells and other pancreatic cell lineages in patients with diffuse congenital hyperinsulinism in infancy caused by mutations in the ATP-sensitive K-channel. Diabetes. 2015;64:3182-3188. 25. Amato LA, Quigley CA, Neville KA, Hameed S, Verge CF, Woodhead HJ, Walker JL. Sirolimus treatment of severe congenital hyperinsulinism. Int J Pediatr Endocrinol. 2015;2015(Suppl 1):P123. 26. Kara C, Yilmaz GC, Dermirbilek H, Flanagan SE, Ellard S, Hussain K, Aydın M. Efficacity and safety of sirolimus (mTOR inhibitor) in two patients with diazoxide- unresponsive hyperinsulinemic hypoglycemia. J Clin Res Pediatr Endocrinol. 2015;7:86. 27. Shah P, Arya VB, Flanagan SE, Morgan K, Ellard S, Senniappan S, Hussain K. Sirolimus therapy in a patient with severe hyperinsulinaemic hypoglycaemia due to a compound heterozygous ABCC8 gene mutation. J Pediatr Endocrinol Metab. 2015;28(5-6):695-699. 28. Minute M, Patti G, Tornese G, Faleschini E, Zuiani C, Ventura A. Sirolimus therapy in congenital hyperinsulinism: a successful experience beyond infancy. Pediatrics. 2015;136(5):e1373-e1376. 29. Méder Ü, Bokodi G, Balogh L, Körner A, Szabó M, Pruhova S, Szabó AJ. Severe hyperinsulinemic hypoglycemia in a neonate: response to sirolimus therapy. Pediatrics. 2015;136:1369-1372. 30. Abraham MB, Shetty VB, Price G, Smith N, Bock Md, Siafarikas A, et al. Efficacy and safety of sirolimus in a neonate with persistent hypoglycaemia following near- total pancreatectomy for hyperinsulinaemic hypoglycaemia. J Pediatr Endocrinol Metab. 2015;28:1391-1398. 31. Houde VP, Brûlé S, Festuccia WT, Blanchard PG, Bellmann K, Deshaies Y, Marette A.Chronic rapamycin treatment causes glucose intolerance and hyperlipidemia by upregulating hepatic gluconeogenesis and impairing lipid deposition in adipose tissue. Diabetes. 2010;59:1338-1348. 32. Bussiere CT, Lakey JRT, Shapiro AMJ, Korbutt GS. The impact of the mTOR inhibitor sirolimus on the proliferation and function of pancreatic islets and ductal cells. Diabetologia. 2006;49(10):2341-2349. 33. Pham P-TT, Pham P-MT, Pham SV, Pham P-AT, Pham P-CT. New onset diabetes after transplantation (NODAT): an overview. Diabetes Metab Syndr Obes Targets Ther. 2011;4:175-186.
72 CHAPTER 5
Vineland adaptive behavior scales to identify neurodevelopmental problems in children with Congenital Hyperinsulinism (CHI)
Maria Salomon-Estebanez1,4, Zainab Mohamed2, Maria Michaelidou1, Hannah Collins3,
Lindsey Rigby1, Mars Skae1, Raja Padidela1, Stewart Rust3, Mark Dunne4, Karen
Cosgrove4, Indraneel Banerjee1,4, Jacqueline Nicholson3
1. Department of Paediatric Endocrinology, Royal Manchester Children’s Hospital, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, UK 2. Department of Paediatric Endocrinology and Diabetes, Nottingham Children's Hospital, Nottingham University Hospitals, Derby Road, Nottingham NG7 2UH, UK 3. Paediatric Psychosocial Department, Royal Manchester Children’s Hospital, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, UK 4. Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
Published in Orphanet J Rare Dis. 2017 May 22;12(1):96. doi: 10.1186/s13023-017-0648-7
73 5.1 Abstract
Background: Congenital Hyperinsulinism (CHI) is a disease of severe hypoglycaemia caused by excess insulin secretion and associated with adverse neurodevelopment in a third of children. The Vineland Adaptive Behavior Scales Second Edition (VABS-II) is a parent report measure of adaptive functioning that could be used as a developmental screening tool in patients with CHI. We have investigated the performance of VABS-II as a screening tool to identify developmental delay in a relatively large cohort of children with
CHI. VABS-II questionnaires testing communication, daily living skills, social skills, motor skills and behaviour domains were completed by parents of 64 children with CHI, presenting both in the early neonatal period (Early-CHI, n=48) and later in infancy (Late-CHI, n=16).
Individual and adaptive composite (Total) domain scores were converted to standard deviation scores (SDS). VABS-II scores were tested for correlation with objective developmental assessment reported separately by developmental paediatricians, clinical and educational psychologists. VABS-II scores were also investigated for correlation with the timing of hypoglycaemia, gender and phenotype of CHI.
Results: Median (range) total VABS-II SDS was low in CHI [-0.48 (-3.60, 4.00)] with scores
<-2.0 SDS in 9 (12%) children. VABS-II Total scores correctly identified developmental delay diagnosed by objective assessment in the majority [odds ratio (OR) (95% confidence intervals, CI) 0.52 (0.38, 0.73), p<0.001] with 95% specificity [area under curve (CI) 0.80
(0.68, 0.90), p<0.001] for cut-off < -2.0 SDS, although with low sensitivity (26%). VABS-II
Total scores were inversely correlated (adjusted R2=0.19, p=0.001) with age at presentation
(p=0.024) and male gender (p=0.036), males having lower scores than females in those with Late-CHI [-1.40 (-3.60, 0.87) v 0.20 (-1.07, 1.27), p=0.014]. The presence of a genetic mutation representing severe CHI also predicted lower scores (R2=0.19, p=0.039).
Conclusions: The parent report VABS-II is a reliable and specific tool to identify developmental delay in CHI patients. Male gender, later age at presentation and severity of disease are independent risk factors for lower VABS-II scores.
74 5.2 Background
Congenital Hyperinsulinism (CHI) is a significant disorder of hypoglycaemia caused by excessive and unregulated insulin secretion [1,2]. CHI usually presents early in the neonatal period (Early-CHI), but later presentation (Late-CHI) is also well recognised [3-5]. A significant proportion of children with Congenital Hyperinsulinism (CHI) have adverse neurodevelopmental abnormalities in spite of improvements in medical care [3,4,6].
Identifying neurodevelopmental outcomes is a priority for children in follow up care; children with developmental needs may require additional support for physical and learning disabilities. The Vineland Adaptive Behavior Scales II© (VABS-II; Pearson Education
Incorporated, San Antonio, Texas) parent report questionnaire is a tool that has been standardised for factors including gender, race, age and parental education, to identify children with developmental delay in the domains of communication, daily living skills, social skills, motor skills and behaviour. VABS-II is useful as an adaptive functioning inventory that could be completed at home without time consuming hospital visits and assessments.
VABS-II has been used in a few children with CHI [7] but its reliability, as a general screening tool to assess developmental delay in this population has not been assessed.
VABS-II could be a credible tool to screen for adverse neurodevelopment in children with
CHI, particularly at a younger age before formal time consuming cognitive testing is feasible. In this study, we have investigated the utility of VABS-II questionnaires as a parent report screening tool to identify developmental abnormalities in a relatively large population of children with CHI.
Aims:
We aimed to:
1. Investigate performance of VABS-II to identify developmental delay in CHI
2. Identify patient factors correlating with VABS-II scores.
5.3 Methods
Parents of a cohort of children with CHI (n=64), presenting consecutively between 2013 and
2015 to a specialist CHI treatment centre, completed the VABS-II questionnaire following
75 consent. The diagnosis and treatment of CHI was based on established criteria and clinical practice [1,2]. Medical and surgical treatment was individualised for each child. Patients’ characteristics and clinical outcome data were obtained from a database of patients. CHI was considered early (Early-CHI) if hypoglycaemia presentation was in the first month of life. Children who presented with hypoglycaemia later than one month had Late-CHI. In such children, neonatal records did not provide evidence for persistent hypoglycaemia.
Following hospital discharge, children with Early and Late-CHI were assessed in the outpatient department by the clinical team comprising of clinicians, specialist nurse practitioners, dietitians, speech and language therapists and one clinical psychologist.
VABS-II was discussed with parents as a routine screening tool for development after the age of 1 year.
VABS-II is a validated measure of intellectual and developmental functioning, and has been used in children with neonatal conditions [8], in neurological problems [9] and in children with genetic problems [10]. VABS-II has also been used in a small cohort of children with
CHI, but its reliability as a screening tool has not been assessed [7]. Although VABS-II can be applied in children from birth, milder forms of developmental delay may not be apparent until an older age when clear progress in several developmental domains is obvious.
Therefore, the minimum age for using the VABS-II was chosen at 18 months. No upper limit was specified; however as scores for motor skills in children > 6 years are estimates, analysis of VABS-II scores were run both with and without children > 6 years.
The VABS-II questionnaire was posted out to parents by the clinical psychologist (JN) who was trained and accredited to use and interpret the VABS-II. Where necessary she contacted parents by telephone to discuss queries about VABS-II responses. Populated questionnaires were returned to her for analysis in each of the domains of Communication,
Daily Living Skills, Social Skills and Motor Skills [www.pearsonclinical.com]. Domain scores were then compounded to derive the Adaptive Behaviour Composite (Total) score. For each
VABS-II domain, scores were converted to Standard Deviation Scores (SDS) based on mean (SD) 15 (3). Total VABS-II scores were also converted to Total VABS-II SDS (VABS-II
Total) based on mean (SD) 100 (15), (total scores are not additive). For each VABS-II domain and for composite scores, SDS <-2.0 was indicative of significant developmental
76 delay. The Behaviour component of VABS-II was independently scored for internalising, externalising and total maladaptive behaviour scores, with raw scores having inverse correlation with behaviour outcomes. High scores corresponded to poor behaviour outcomes; for total Behaviour, scores > 20 were considered unsatisfactory.
VABS-II was assessed for repeat variability by comparing initial report with a second report in a volunteer group (n=7) after at least 1 year. The repeat assessment was performed to investigate if VABS-II demonstrated variability in relation to the timing of the test that could affect the interpretation of results. VABS-II was also analysed in a group of children with idiopathic ketotic hypoglycaemia (IKH) with normal neurodevelopment (n=9) to assess test performance in an alternative condition of hypoglycaemia without significant adverse neurodevelopment.
VABS-II scores were compared with objective developmental assessment performed within
6 months of reporting. This assessment was performed by developmental paediatricians, clinical psychologists and educational psychologists who were unaware of VABS-II performance scores. The parents of children with CHI were unaware of the VABS-II scores and report until after the objective developmental assessment was performed. However, this testing was not centralised to the CHI centre; instead objective developmental assessment relied on methods specific to the local health authority, and were blinded to the results of
VABS-II scores. However, derogation to local services meant that uniformity of formal testing was not maintained although the choice of formal developmental assessment allowed flexible testing in children of all abilities. The following developmental assessments were utilised - Wechsler Preschool and Primary Scale of Intelligence for Children – UK 4th
Edition (WPPSI-IV), Wechsler Intelligence Scales for Children, 4th edition (WISC-IV UK),
Movement Assessment Battery for Children – UK Second Edition (MAS-2), Bayley Scales of
Infant and Toddler Development - Third Edition (Bayley-III) and Griffiths Developmental
Scales. Objective assessment reports were available in 15 children, 6 from our centre and 9 from elsewhere. In the rest, information describing cognitive and developmental outcomes was obtained from patient clinical correspondence and reports obtained from community paediatricians and school assessments by educational psychologists. Formal or informal
77 developmental testing was performed independent of VABS-II testing in all children in the cohort; therefore the study design did not control for the severity of neurodevelopmental outcome. As these tests varied in their reporting styles, no attempt was made to achieve uniformity of output, except for recording the presence or absence of delay in one or more domains of childhood development in the following categories – gross motor, fine motor, social and adaptive, communication and language. Brain neuroimaging was not performed routinely but reserved for clinical need.
VABS-II scores were also investigated for correlations with the timing of hypoglycaemia presentation, gender and phenotypes of CHI which included focal (solitary hyperfunctioning lesion in the pancreas), diffuse (hyperfunction in all islets in the pancreas) and transient
(resolving hypoglycaemia, not requiring surgical treatment or long term medical therapy) forms, and treatment response. Transient and persistent CHI were defined as per previous descriptions [3,11] with persistent forms indicating requirement for medication or need for pancreatic surgery. Genetic mutation status was determined by testing for known genes associated with CHI as previously described using standard methods [11]. Mutation status was positive if any pathologic mutation was present, in heterozygous or homozygous form, regardless of the mode of inheritance. CHI gene mutation was utilised as a proxy for greater severity, with known genetic forms having a greater requirement for medical or surgical therapy and less likely to achieve resolution of disease [11]. However, it is accepted that severity can be variable within individuals with the same genotype, between heterozygous, homozygous and compound heterozygous mutations and between KATP channel genes and non KATP channel genes. It is also possible that children without genetic mutations may have severe disease. While genetic mutation status is not an ideal severity marker, other markers such glucose infusion rates were not obtainable in patients with mild forms of CHI and those presenting late. We also utilised other severity markers such as response to diazoxide, transient or persistent CHI and requirement for surgery, although we accept that such markers are not validated, may be non-concordant, may represent a disproportionately severe end of the spectrum of disease and introduce bias in statistical correlations.
VABS-II was also tested in 9 children with IKH (age range 3.00 to 5.40 years), to assess
78 performance in children with hypoglycaemia not due to CHI. These children presented with ketotic forms of hypoglycaemia in 2014-2015 and underwent investigations to exclude known causes of hypoglycaemia including CHI. Children who were recruited to the study did not have formal developmental assessment. However they were reviewed by the clinical psychologist who ensured normal neurodevelopment. Their hypoglycaemia was not treated by regular medication/food supplements but instead emergency hypoglycaemia prevention protocols incorporating additional carbohydrate intake during illness episodes were adopted.
Statistical analysis was performed by SPSS IBM© version 23.0 (IBM, New York, USA).
VABS-II SDS between groups were compared by non-parametric tests. For repeat samples, paired tests with unequal variances were utilised. Probability of group membership was assessed by odds ratio, while sensitivity and specificity of tests were checked by receiver operating characteristic (ROC) curve analysis. The study was supported by the North West
Research Ethics Committee, Project Reference Number 07/H1010/88.
5.4 Results
VABS-II scores were completed in 64 (44 males, 69%) children with CHI at median (range) age 4.5 (1.5, 16.8) years, of whom 16 children (25%) were Late-CHI, with presentation at age 0.80 (0.30, 3.50) years. Individual and total VABS-II domain SDS scores (VABS-II scores) were below the expected population mean (range) [0 (-2.0, 2.0)] in the majority of patients (n=41, 64%), with 9 (12%) being less than -2.0. VABS-II scores were as follows:
Communication -0.26 (-3.33, 2.93), Daily Living Skills -0.73 (-3.60, 1.80), Social Skills -0.33
(-3.13, 1.87), Motor Skills -0.60 (-3.80, 1.80) and Total -0.48 (-3.60, 4.00). VABS-II scores were higher in Early-CHI than Late-CHI, although not reaching significance [-0.47 (-2.74,
4.00) v -0.70(-3.60, 1.27), p=0.51], Figure 5.1. VABS-II scores were in the normal population range [-0.33 (-1.73, 1.13)] for 9 children with IKH, in keeping with prior normal objective developmental assessment. VABS-II was repeated in 7 children (age range 3.00 to 9.30 years) with CHI; individual domain and total scores remained similar [paired samples test, p=0.18 to p=0.95], suggesting that the VABS-II was valid on repetition without significant deviation with advancing age.
79
Figure 5.1 VABS-II scores in Early and Late CHI. VABS-II scores have been expressed as SDS in patients with Early-CHI and Late-CHI for individual and adaptive behaviour composite (Total) domains. The reference line at 0 SDS represents the population mean with values < -2.0 representing significant deviation.
VABS-II scores in CHI correlate with developmental delay
VABS-II scores were correlated with developmental delay (affected in at least one developmental domain) identified by objective developmental assessment, Table 5.1.
Correlation was also sustained for involvement of one or more developmental domains regarded as a yes/no binary variable [odds ratio, OR (confidence interval, CI) 0.28 (0.13,
0.61), p=0.001]. As motor skills scores were estimated in a group of children > 6 years old
(n=14), the analysis was re-run in the subgroup of children < 6 years old (n=50) demonstrating a persistent strong correlation with developmental delay [OR (CI) 0.63 (0.44,
0.90), p=0.012]. Lower VABS-II scores were also more likely in children with seizures at presentation [OR (CI) 0.49 (0.31, 0.76), p=0.002] and epilepsy [OR (CI) 0.22 (0.09, 0.59), p=0.003], further adding to the strength of association between VABS-II and developmental phenotyping in CHI.
80 VABS-II domains correlating Odds ratio 95% Confidence p value with developmental delay Intervals Total score 0.52 0.38; 0.73 <0.001 Communication 0.46 0.33; 0.65 <0.001 Daily Living Skills 0.63 0.44; 0.89 0.009 Social Skills 0.58 0.43; 0.78 <0.001 Motor Skills 0.54 0.38; 0.78 <0.001 Total Behaviour 1.21 1.04; 1.41 0.013 Externalising Behaviour 1.09 0.94; 1.27 0.251 Internalising Behaviour 1.30 1.09; 1.55 0.005 Table 5.1 Individual and total VABS-II domain correlations with developmental delay by objective assessment performed by developmental paediatricians, clinical and educational psychologists. Development was delayed if one or more domains (gross motor, fine motor, social and adaptive, language and communication) were affected. Total and individual domain VABS-II scores showed higher probability of developmental delay with lower scores. Total Behaviour scores showed a higher probability for higher scores, mainly for internalising behaviour.
Receiver operating characteristic (ROC) curves [area under curve (AUC) (CI) 0.80 (0.68,
0.90), p<0.001] were used to test sensitivity and specificity of VABS-II Total scores to identify developmental delay. At a VABS-II Total score -1.0 SDS, sensitivity was 63% and specificity was 79%. At a VABS-II Total score -2.0 SDS, sensitivity reduced to 26%, but specificity increased to 95%. Thus, while VABS-II Total scores < -2.0 SDS did not have a high pick up rate, an accurate diagnosis of developmental delay was ensured. For internalising behaviour scores, the ROC AUC associating with developmental delay was
0.78 (0.60, 0.95), p=0.008 with a score of 15 showing sensitivity of 80% and specificity of
95%. With a behaviour score of 20, sensitivity reduced to 50%, but specificity increased to
91%. When VABS-II scores were analysed for predictive value for developmental delay in more than one domain [ROC AUC 0.80 (0.67, 0.92), p=0.001], VABS-II Total score -1.8 SDS yielded sensitivity of 50% and specificity of 92%. Thus VABS-II and behaviour scores had high specificity for the diagnosis of developmental delay, with a low yield of undue false positive cases.
VABS-II scores correlate with phenotypes of CHI
(1) Correlations with age and gender:
VABS-II Total scores were negatively correlated with advancing age at presentation of hypoglycaemia [adjusted R2=0.23, p=0.018], Figure 5.2.
81
Figure 5.2 Scatterplot of VABS-II Total scores for age at presentation of hypoglycaemia. Open triangles representing Early-CHI and filled circles representing Late- CHI. The reference line at 0 SDS indicates that most values in Late-CHI were below average. Older age at presentation was associated with lower VABS-II Total scores.
In linear regression (adjusted R2=0.19, p=0.001), age at presentation (p=0.024) and male gender (p=0.036) were independently correlated with lower VABS-II scores. As a group, male scores were lower than females [-0.93 (-3.60, 4.0) v 0.00 (-2.07, 2.27), p=0.020] regardless of their age. The difference was observed mainly within the domains of communication (p=0.012) and social skills (p=0.009), but not within daily living skills
(p=0.135) or motor skills (p=0.187). Within Late-CHI, male scores were lower than females
[-1.40 (-3.60,0.87) v +0.20 (-1.07,1.27), p=0.014]. In analysis of covariance (R2=0.11, p=0.011), male gender demonstrated an additional modest 6.5% effect (p=0.04) on age at presentation to influence VABS-II Total scores. Therefore males presenting late carried higher risk for adverse neurodevelopmental outcomes, Figure 5.3.
82 Figure 5.3 Clustered box and whisker plots of VABS-II Total scores in Early-CHI and Late-CHI. Males represented in white and females represented in grey. This figure shows adverse VABS-II scores in males presenting late.
(2) Linking VABS-II scores to CHI severity:
VABS-II scores were analysed for correlation with disease severity. Various phenotypic characteristics describing severity of CHI in our cohort has been provided in Appendix 5.A.
Carriage of CHI gene mutations serving as a possible proxy for greater severity correlated with lower VABS-II Total scores in analysis of covariance with age at presentation as the covariate [adjusted R2=0.19, p=0.039] with a modest effect size of 10%. In keeping with mutation status as a marker of severity, responsiveness to diazoxide was also positively correlated with VABS-II, i.e. unresponsiveness to diazoxide was associated with lower
VABS-II Total scores (p=0.019); however, no significant effects were noted for the following factors: transient or permanent CHI (p=0.413), focal CHI (p=0.742) and pancreatic surgery
(p=0.132).
83 VABS-II Behaviour scores in CHI
There were no differences in maladaptive behaviour scores between males and females for total, externalising and internalising behaviour scores (p=0.949, p=0.288, p=0.710 respectively). Similarly, no differences in Early-CHI and Late-CHI were observed in total and each behaviour domain (p=0.226, p=0.760, p=0.096). When adjusting for gender, age at presentation did not correlate with behaviour (p=0.811, p=0.744, p=0.561). However, greater total behaviour scores were associated with developmental delay [OR (95%CI) 1.21
(1.04, 1.41), p=0.013], Figure 5.4, more so for internalising behaviour [OR (95%CI) 1.30
(1.09, 1.55), p=0.005] than for externalising behaviour (p=0.251). However, the combination of total Vineland scores and total maladaptive behaviour scores (as a composite measure) to predict developmental delay was not additionally informative
(p=0.836). Therefore it follows that total maladaptive behaviour scores or total VABS-II scores are individually correlated with developmental delay but without additive effects.
Figure 5.4 Association of total behaviour scores with developmental delay. Box and whisker plot showing increasing total behaviour scores correlating with increasing severity of developmental delay.
84 5.5 Discussion
In this study, we have assessed the reliability of VABS-II as a screening tool for developmental delay in children with CHI. VABS-II and maladaptive behaviour scores individually correlated with developmental delay. VABS-II had high specificity, indicating accuracy of screening investigations for formal developmental assessments. Male gender and late age of hypoglycaemia presentation were risk factors for lower VABS-II scores.
Diazoxide unresponsiveness and carriage of CHI genetic mutations, proxy markers of severity of CHI, were also associated with lower VABS-II scores.
Although VABS-II is applied widely to children with different conditions, its utility and accuracy in children with CHI has not been investigated previously. Our study has reviewed the performance of VABS-II in a relatively large cohort of children with the rare disease of
CHI, over a two-year period and correlated parent reports with objective clinical developmental examination. Further, our study examined VABS-II in IKH, where hypoglycaemia is not usually associated with significant brain injury; as expected VABS-II showed normal variation in IKH individuals. Our study also found consistency in repeating
VABS-II in later life, thereby eliminating age dependent bias. The strength of association of
VABS-II with developmental delay and the observation that a third of children have abnormal neurodevelopment [3] makes a compelling case to use VABS-II routinely in children with CHI with any clinical concern about neurodevelopment.
Although VABS-II demonstrated strong correlation with developmental delay and had high specificity, formal assessment methods to diagnose developmental delay were not uniform.
However as cognitive testing using inventories such as WISC-IV UK can be time consuming, require trained psychologists and may be unsuitable for younger children, flexibility of objective developmental assessment was inevitable. Nonetheless, the non- uniformity of formal developmental testing remains a weakness, which may account for the skewed sensitivity values of VABS-II. It does reflect the variability that exists within clinical practices, however.
The study design did not specify formal developmental testing for all patients. It is possible that more patients who had severe neurodevelopmental delay were tested by formal
85 methods than those with mild delay. However, in those tested formally in our cohort, nearly half were tested routinely. In such patients, testing was not biased by the severity of adverse neurodevelopment. It is possible that the sensitivity of VABS-II for milder adverse neurodevelopment is higher than that observed. An important corollary from our observations is the need for a more rigorous test of performance of VABS-II in the detection of milder forms of developmental delay. We recognise that mild abnormalities due to early life hypoglycaemia may not be reversed by early detection by VABS-II; however it is possible that early therapeutic interventions and adaptions in home and learning environments could be beneficial. The identification of relatively subtle neurodevelopmental abnormalities and interventions on quality of life could be a logical follow on study.
In this study, brain imaging was not performed as routine. Instead brain magnetic resonance imaging was prioritised for clinical need as in a previous observational study [3]. While the absence of brain imaging could be construed as a weakness in the study design, the value of routine brain imaging, a resource intense investigation, has not been substantiated for neurodevelopmental screening of CHI other than to identify the topography of lesions [12].
VABS-II had high specificity but low sensitivity for developmental delay. Therefore in the context of screening, VABS-II may not be relied upon as a primary tool for developmental referral in CHI. However, in clinical practice, developmental concerns are routinely discussed in outpatient follow up, which would obviate the requirement for VABS-II to be a highly sensitive instrument. The clinical suspicion of delayed development could be construed as a first line screening test, followed by VABS-II as a next step screening tool.
The high specificity of VABS-II in the context of clinical concerns should generate sufficient concern to trigger referral for formal developmental assessments.
It is not clear why males with CHI have lower VABS-II scores than females. Frequency of males was greater in our cohort; however, gender as a variable was controlled in analysis at several levels. Our study has raised the interesting question whether gender difference could be an independent predictor over hypoglycaemic brain injury to cause intellectual disability. This question cannot be answered within the remit of our study design and needs to be examined in larger cohorts. Recent observations suggest modulation of sensitivity of
86 arcuate nuclei to hypoglycaemia by suprachiasmatic nuclei in male rats [13]; it remains to be seen if similar mechanisms apply to male brains in children with CHI.
Our study shows that children presenting later with CHI have lower VABS-II scores, correlating with adverse developmental outcomes. This observation remains even after adjustment for male gender, another risk factor for lower VABS-II scores. CHI usually presents in the neonatal period; it is possible that patients with Late CHI had neonatal hypoglycaemia but that the diagnosis was achieved later. However, examination of neonatal records makes this less likely, although not impossible. A previous observation of later presentation has been associated with long term neurological disabilities [4] suggesting recurrent and unrecognised hypoglycaemia impacting on developmental outcomes. In our cohort, it is likely that recurrent hypoglycaemia was missed prior to the eventual diagnosis of CHI. Such hypoglycaemic episodes could be responsible for greater severity of adverse neurodevelopment in those with Late CHI. The inverse correlation with age at presentation indicates the need for early recognition and treatment of hypoglycaemia in early life [1,14].
As expected, diazoxide unresponsiveness and carriage of genetic mutations, proxy markers of severity of CHI, were associated with lower VABS-II scores. It therefore follows that treatment response and gene mutation testing in the initial phase of clinical management may provide prognostic markers to determine neurodevelopmental trajectories in CHI. It is well recognised that patients undergoing pancreatectomy for CHI have a high frequency of neurobehavioural deficits [15]. Our study adds further evidence to the impact of severity phenotyping on long-term outcomes.
5.6 Conclusions
We have evaluated the performance of Vineland Adaptive Behavior Scales, 2nd edition
(VABS-II) in children with CHI and noted lower scores correlating with the presence of developmental delay with high specificity. Male gender, late age at presentation and severity of CHI are risk factors for adverse outcomes. VABS-II can be reliably used in neurodevelopmental follow up of CHI patients to trigger formal developmental assessment.
87
List of Abbreviations
CHI: Congenital Hyperinsulinism, VABS-II: Vineland Adaptive Behavior Scales, second edition, SDS: standard deviation scores, OR: odds ratio, CI: confidence intervals, IKH: idiopathic ketotic hypoglycaemia, WPPSI-IV: Wechsler Preschool and Primary Scale of
Intelligence for Children – UK 4th Edition, WISC-IV UK: Wechsler Intelligence Scales for
Children, 4th edition, MAS-2: Movement Assessment Battery for Children – UK Second
Edition, ROC: receiver operating characteristic, AUC: Area Under the Curve.
Declarations
Ethics approval and consent to participate: This study was supported by the North
West Research Ethics Committee (project reference number: 07/H1010/88) to
which parents were consented to participate.
Consent for publication: Not applicable (no individual patient information disclosed).
Availability of data and material: All data generated or analysed during this study
are included in this published article in the format uploaded.
Competing interests: There are no competing interests.
Funding: The study received funding from the following sources: National Institute
for Health Research, Translational Research Collaboration, NORCHI Charitable
Fund, Research and Innovation supporting funds from Central Manchester
University Hospitals and University of Manchester and The Million Dollar Bike Fund.
KEC was funded by a Research Councils UK Academic Fellowship.
Authors' contributions: IB, JN and SR conceived and designed the study. MSE, ZM,
MM, HC and LR were involved in data collection. MSE, ZM, JN and IB analysed
and interpreted the data, including statistical analysis. MS, RP, SR, MD and KC
critically revised the manuscript. All authors read and approved the final manuscript.
Acknowledgements: The authors are grateful to research nurses and clinical
colleagues at Central Manchester University Hospitals NHS Trust and the
Manchester Biomedical Research Centre.
88 5.7 References
1. Arnoux JB, Verkarre V, Saint-Martin C, Montravers F, Brassier A, Valayannopoulos V, et al. Congenital hyperinsulinism: current trends in diagnosis and therapy. Orphanet J Rare Dis. 2011;6:63. 2. Banerjee I, Avatapalle B, Padidela R, Stevens A, Cosgrove KE, Clayton PE, Dunne MJ. Integrating genetic and imaging investigations into the clinical management of congenital hyperinsulinism. Clin Endocrinol. 2013;78(6):803-13. 3. Avatapalle HB, Banerjee I, Shah S, Pryce M, Nicholson J, Rigby L, et al. Abnormal Neurodevelopmental Outcomes are Common in Children with Transient Congenital Hyperinsulinism. Front Endocrinol (Lausanne). 2013;4:60. 4. Meissner T, Wendel U, Burgard P, Schaetzle S, Mayatepek E. Long-term follow-up of 114 patients with congenital hyperinsulinism. Eur J Endocrinol. 2003;149(1):43- 51. 5. Touati G, Poggi-Travert F, Ogier de Baulny H, Rahier J, Brunelle F, Nihoul-Fekete C, et al. Long-term treatment of persistent hyperinsulinaemic hypoglycaemia of infancy with diazoxide: a retrospective review of 77 cases and analysis of efficacy- predicting criteria. Eur J Pediatr. 1998;157:628-33. 6. Menni F, de Lonlay P, Sevin C, Touati G, Peigne C, Barbier V, et al. Neurologic outcomes of 90 neonates and infants with persistent hyperinsulinemic hypoglycemia. Pediatrics. 2001;107(3):476-479. 7. Levy-Shraga Y, Pinhas-Hamiel O, Kraus-Houminer E, Landau H, Mazor-Aronovitch K, Modan-Moses D, et al. Cognitive and developmental outcome of conservatively treated children with congenital hyperinsulinism. J Pediatr Endocrinol Metab. 2013; 26:301-308. 8. Hack M. Consideration of the use of health status, functional outcome, and quality- of-life to monitor neonatal intensive care practice. Pediatrics. 1999;103(1 Suppl E):319-28. 9. Berg AT, Caplan R, Baca CB, Vickrey BG. Adaptive behavior and later school achievement in children with early-onset epilepsy. Dev Med Child Neurol. 2013; 55(7):661-7. 10. Msall ME, Tremont MR. Measuring functional status in children with genetic impairments. Am J Med Genet. 1999;89(2):62-74. 11. Banerjee I, Skae M, Flanagan SE, Rigby L, Patel L, Didi M, et al. The contribution of rapid KATP channel gene mutation analysis to the clinical management of children with congenital hyperinsulinism. Eur J Endocrinol. 2011;164(5):733-740. 12. Gataullina S, Lonlay PD, Dellatolas G, Valayannapoulos V, Napuri S, Damaj L, et al. Topography of brain damage in metabolic hypoglycaemia is determined by age at which hypoglycaemia occurred. Dev Med Child Neurol. 2013;55:162-166. 13. Herrera-Moro Chao D, Leon-Mercado L, Foppen E, Guzman-Ruiz M, Basualdo MC, Escobar C, Buijs RM. The Suprachiasmatic nucleus modulates the sensitivity of Arcuate nucleus to hypoglycemia in the male rat. Endocrinology. 2016;157(9):3439- 51. 14. De Leon DD, Stanley CA. Mechanisms of Disease: advances in diagnosis and treatment of hyperinsulinism in neonates. Nat Clin Pract Endocrinol Metab. 2007;3(1):57-68. 15. Lord K, Radcliffe J, Gallagher PR, Adzick NS, Stanley CA, De Leon DD. High Risk of Diabetes and Neurobehavioral Deficits in Individuals With Surgically Treated Hyperinsulinism. J Clin Endocrinol Metab. 2015;100(11):4133-4139.
89 Appendix 5.A Clinical descriptors of patients
Late or Early Mutation Transient or Responsive to Surgery Focal or Diffuse Total VABS-II SDS Presenting Persistent Medication # 1 E Paternal ABCC8 P Unresponsive SP D -0.9 # 2 L Negative P Diazoxide No D -2.6 # 3 L Negative P Diazoxide No D -1.3 # 4 E Compound P Unresponsive SP D -0.9 heterozygous ABCC8 # 5 L Negative P Diazoxide No D -1.1 # 6 L GCK P Diazoxide No D -2.6 # 7 E Negative T Diazoxide No D -1.9 # 8 E Paternal KCNJ11 T Diazoxide No D -1.1 # 9 E Paternal ABCC8 P Unresponsive FL F -2.3 # 10 E Negative P Diazoxide No D -2.5 # 11 E Negative P Diazoxide No D -1.3 # 12 L Negative P Unresponsive SP D -3.6 # 13 E Homozygous P Unresponsive SP D -1.1 ABCC8 # 14 L Negative P Diazoxide No D 0.7 # 15 E Negative T Diazoxide No D 1.9 # 16 E Negative T Diazoxide No D -0.8 # 17 E Negative P Unresponsive SP D 1.1 # 18 E Maternal KCNJ11 T Diazoxide No D -0.4 # 19 L Negative T Diazoxide No D 0.2 # 20 E Negative T Diazoxide No D -0.5 # 21 E Maternal ABCC8 T Diazoxide No D 0.1 # 22 E Paternal ABCC8 T Diazoxide No D -2.1 # 23 E Maternal ABCC8 P Diazoxide No D -1.7 # 24 L Negative P Diazoxide No D -1.4 90 Late or Early Mutation Transient or Responsive to Surgery Focal or Diffuse Total VABS II SDS Presenting Persistent Medication # 25 E Negative T Glucose No D 0.3 # 26 L Negative P Diazoxide No D -0.3 # 27 E Negative T Diazoxide No D -1.5 # 28 E de novo ABCC8 P Diazoxide No D 2.3 # 29 E Negative T Diazoxide No D -0.8 # 30 L Negative P Diazoxide No D -0.2 # 31 E Negative T Glucose No D -2.1 # 32 L Negative T Diazoxide No D -0.1 # 33 L Paternal ABCC8 T Octreotide No D -1.4 # 34 E Paternal ABCC8 T Octreotide No D -2.7 # 35 L Negative T Diazoxide No D 1.3 # 36 E Maternal ABCC8 T Diazoxide No D 0.0 # 37 L Paternal ABCC8 P Diazoxide FL F 0.9 # 38 E Negative T Diazoxide No D 0.7 # 39 E Negative T Glucose No D 1.4 # 40 E Negative T Diazoxide No D -1.3 # 41 E Negative P Diazoxide No D -1.3 # 42 E Negative T Diazoxide No D -1.4 # 43 E Negative T Diazoxide No D -1.3 # 44 E Negative P Diazoxide No D 1.3 # 45 E Negative T Diazoxide No D 4.0 # 46 L Negative T Diazoxide No D -1.5 # 47 L Negative T Diazoxide No D 1.3 # 48 E Negative T Diazoxide No D 0.5 # 49 E Paternal KCNJ11 T Octreotide No D -0.3 # 50 E Negative T Diazoxide No D -0.2 91 Late or Early Mutation Transient or Responsive to Surgery Focal or Diffuse Total VABS II SDS Presenting Persistent Medication # 51 E Negative P Diazoxide No D 0.0 # 52 E Negative P Diazoxide No D -0.9 # 53 E Negative T Diazoxide No D 0.3 # 54 E Homozygous P Unresponsive SP D -2.6 ABCC8 # 55 E Negative T Diazoxide No D 0.9
# 56 E Homozygous P Octreotide No D -0.4 ABCC8 # 57 E Negative T Diazoxide No D -0.6 # 58 E Negative P Diazoxide No D 2.2 # 59 E Paternal KCNJ11 P Octreotide No D -1.9 # 60 E Negative T Diazoxide No D -0.4 # 61 E Compound P Octreotide No D 0.9 heterozygous ABCC8 # 62 E Negative T Diazoxide No D 0.5 # 63 E Negative T Diazoxide No D -0.5 # 64 E Negative T Diazoxide No D 0.1 Clinical descriptors in patients with CHI with time of presentation, genetic status, resolution of hypoglycaemia, response to medication, requirement for pancreatic surgery and Total VABS-II scores. - E: early, L: late, T: transient, P: permanent, D: diffuse, F: focal, FL: focal lesionectomy, SP: subtotal pancreatectomy - All patients on octreotide had previously failed to respond to diazoxide. - Outcomes of surgery: Patients with focal CHI were cured after focal lesionectomy. Patient # 1 and # 13 became diabetic post-pancreatectomy; patient # 12 and # 54 are euglycaemic post-pancreatectomy; patients # 4 and #17 have impaired glucose tolerance.
92 CHAPTER 6: GENERAL DISCUSSION
Natural history data of the rare disease CHI is limited and this thesis adds important information to current knowledge. Medically managed patients with KATP CHI show a gradual reduction in severity over time and disease resolution is achieved in a significant proportion of patients. This supports conservative management in selected cases. New therapeutic agents are currently under investigation, to avoid the irreversible and lifelong consequences of subtotal pancreatectomy. The use of Sirolimus is associated with limited efficacy and poor safety profile and therefore should not routinely be used in CHI patients. Our experience of sirolimus indicates the need for caution in employing “novel” medication and mandates that new therapies should be rigorously tested for safety and efficacy.
Neurodevelopmental surveillance is essential for all CHI patients, as the risk of adverse neurodevelopment remains high. We have demonstrated that the VABS-II questionnaire is a reliable tool to assess neurodevelopment in patients with CHI. It is important to consider neurodevelopmental outcomes in future trials of therapies in CHI. As we have shown that the VABS-II score correlates with developmental status, this validated tool may be useful to benchmark long-term outcomes in patients with CHI.
6.1 Outcomes of medically treated CHI patients
More information on the natural history of the disease, particularly on patients with severe
CHI that have been conservatively treated is required. While homozygous and compound heterozygous ABCC8/KCNJ11 mutations have classically been associated with permanent
CHI, in Chapter 3 of this Thesis, it is demonstrated that in medically treated patients with
KATP channel gene mutations, a temporal reduction in severity of the hyperinsulinism is seen in all patients. Furthermore, remission can be achieved even in patients with severe forms, including focal CHI.
It is well known that patients with CHI associated to perinatal risk factors (being born small for gestational age, perinatal stress) are generally responsive to diazoxide and there is a gradual reduction in severity over time until the disease resolves [1]. Reduction in severity and resolution is also observed in patients with KATP CHI, not only in those treated with
93 diazoxide but also in patients treated with SSA. Time to resolution is variable from months to several years and is longer in patients treated with SSA than in those treated with diazoxide in our study, implying a more severe disease in diazoxide-unresponsive patients, as expected.
Markers at presentation that could predict the likelihood of resolution have not been identified. In our cohort, maximum dose of diazoxide was higher in patients with persistent
CHI. All of our patients on SSA and all patients with recessively inherited CHI resolved. The numbers may be small, but sample size is not so small in the context of a rare disease.
Unfortunately, no genotype:phenotype associations could be made. The same mutation can cause a variable phenotype and will not predict persistence or resolution of CHI. Previous authors have already described the great variability in the severity of disease, including diazoxide responsiveness, between patients with the same mutations and between affected siblings with diffuse disease within the same family [2].
Disease resolution in medically treated KATP CHI has been reported [2,3,4]. Time to resolution in our cohort was similar to other publications. In 2007, Mazor-Aronovitch et al [2] reported disease resolution in a whole group of 21 patients with ABCC8 mutations (9 homozygous, 3 compound heterozygous and 9 paternally inherited presumed to be focal).
Clinical remission happened significantly earlier in patients with paternally inherited mutations [1.7 years (0.3-5)] than in patients with homozygous and compound heterozygous mutations [5 years (1.5-12)]. 23% had learning problems, which is a similar rate to other cohorts and none developed diabetes. Arya et al [3] reported disease resolution in 57% of patients with medically treated CHI caused by paternally inherited ABCC8/KCNJ11 mutations. Remission happened after a mean duration of 1.48 years (1month - 5 years). A review of 113 articles [4], mainly case reports and case series, included 619 CHI medically treated patients and revealed that 13% (69/521) of patients treated with diazoxide resolved after a mean duration of 4.7 years versus 22% (22/100) of patients on somatostatin receptor agonists that achieved remission after a mean duration of 4 years.
In our cohort, reduction in the intensity of treatment over time occurs in all medically treated
KATP CHI patients, highlighting the importance of periodically assessing the severity of the
94 disease, aiming to reduce the medication dose if there is clinical stability. The mechanisms of remission are unknown. It has been proposed that increased β-cell apoptosis occurs in
CHI, with slow and progressive loss of β-cell mass that could be responsible for the resolution of the hyperinsulinism and progression to diabetes [5], however no clear mechanism has yet been established.
Importantly, neurodevelopmental outcomes are no different between resolved and persistent
CHI patients in our cohort and the rate of developmental problems was similar to other reports [6,7]. Neurodevelopmental outcomes have also been found to be similar in surgically treated compared to medically treated CHI patients [8,9].
The long-term outcomes for patients with dominantly acting ABCC8 mutations need to be explored further. It is known that some of these patients are at risk of developing diabetes in later life after CHI resolution [10,11,12], however, there is not enough data on likelihood of diabetes in later life, age of onset, screening and management.
While CHI patients with other genetic forms of CHI (different to KATP CHI) are generally diazoxide-responsive, there is no data on the long-term outcomes and potential disease resolution. Of particular interest are patients with mutations in HNF4A that following remission of the hyperinsulinism, may develop maturity-onset diabetes of the young type 1
[13].
6.2 mTOR inhibitors in CHI
In an attempt to avoid subtotal pancreatectomy and its lifelong complications, four CHI patients unresponsive to conventional medical treatment with diazoxide and octreotide were recruited and commenced on sirolimus between 2014 and 2016. In contrast to previous reports [14-17], sirolimus was only effective in one of our four patients despite sirolimus levels being within or above the therapeutic range. Two of our patients showed partial response to sirolimus, but not satisfactory enough to allow discharge home or prevent pancreatectomy. The fact that three of our patients had homozygous ABCC8 mutations, implying a more severe disease, may have contributed to the poor sirolimus response.
In the original publication [14], only one out of four patients had the most severe form of the
95 disease, caused by a homozygous mutation in ABCC8, whilst two patients had maternally inherited ABCC8 mutations and in the other patient, no mutations were identified. The patient with the homozygous mutation required octreotide as well as sirolimus to achieve good glycaemic control, whilst the other three patients were weaned off all other therapies after the introduction of the mTOR inhibitor.
Adverse events such as severe episodes of sepsis and symptomatic exocrine pancreatic insufficiency complicated the management of our patients and subtotal pancreatectomy was finally required in three of them.
Successful use of sirolimus has been reported in three independent patients with compound heterozygous ABCC8 mutations [15,16,17]. However, two of these patients also needed additional treatment with diazoxide or octreotide [15,16]. Furthermore, important side effects were reported including mucositis, raised liver enzymes, raised cholesterol and triglycerides.
Episodes of sepsis have also been associated to sirolimus [18], as well as poor linear growth
[19], renal and hepatic failure [18,20] and precipitating diabetes mellitus [21].
The mechanism of action of sirolimus in the pancreas is not completely clear. Previous reports have proposed that the effect of sirolimus on CHI tissue is partly due to a reduction in cell proliferation [16]. However, in pancreatic tissue from two of our patients treated with sirolimus, we have shown that there is no reduction in cell proliferation when compared to age-matched controls or with CHI pancreas not treated with sirolimus. The fact that these two patients were not responsive to sirolimus and that there was a time gap between discontinuation of treatment and pancreatectomy may have had an impact on our results. In our publication [22] we were able to demonstrate using informatics and network biology, that despite the fact that the mTOR signaling pathway was associated with change in focal CHI tissue, it was not associated with the CHI disease interactome. This would explain why some actions on tissue may be expected, but not a reversal of the disease profile.
Our data was published in combination with 6 other CHI patients treated with sirolimus or everolimus in France, with similar efficacy rates and side effects [22]. Further publications have illustrated the unsuccessful use of sirolimus in CHI patients, particularly in those with
96 the most severe forms of the disease caused by homozygous KATP channel mutations [23]. A recent study including a total of 22 patients showed only partial response in 20 patients and significant rates (86%) of complications, being infection, diarrhea and hyperglycaemia the most frequent [24]. The use of sirolimus may have a role in selected cases for a certain period of time, such as for patients with persistent hyperinsulinism post-pancreatectomy [25].
However, at the moment it does not constitute an effective and safe alternative to pancreatectomy. The need for new medical therapies to overcome hyperinsulinism in the severe diffuse CHI cases still persists and future work is focused at developing and trialing new drugs that can safely and effectively prevent pancreatectomy.
6.3 Neurodevelopment in CHI
The reported rate of neurodevelopmental problems varies depending on the cohorts (26% to
48%) [2, 6-9, 26-29] and it has not decreased despite recent improvements in diagnosis and management of the condition in the last decade.
The performance of the VABS-II questionnaire as a neurodevelopmental screening tool has been assessed in this thesis. This questionnaire has proven to be a reliable test when compared with objective developmental assessment. In our study, male gender and late age at presentation were found to be potential risk factors for adverse neurodevelopmental outcomes, as well as severity of the disease (patients carrying a CHI gene mutation or not responding to diazoxide). No other factors such as transient or permanent CHI, focal CHI or pancreatic surgery had an impact on VABS-II scores.
Other publications have identified risk factors associated with worse neurodevelopmental outcomes. Blood glucose levels <1.0 mmol/L and delayed expert treatment were related to impaired neurodevelopment in a multinational cohort study of 75 CHI patients [28]. They detected neurodevelopmental problems in 47% patients, using a variety of psychological assessments including Bayley Scales of Infant and Toddler Development 3rd Edition
(Bayley-III), Developmental Profile 3 (DP-3), Movement Assessment Battery for Children 2
(Movement ABC-2), and Wechsler’s Intelligence Scale for Children fourth edition (WISC-IV).
97 Publications around neurodevelopment in CHI patients are very heterogeneous and many different methods have been used to evaluate neurodevelopmental problems, which may affect the diversity of the results. Standardised psychometric tests were used by Ludwig et al
[29] in a cohort of 60 patients to determine the cognitive, motor, speech, and social- emotional development. They used the Bayley Scales III, Kaufman Assessment Battery for
Children (KABC), Wechsler Intelligence Scale for Children (WISC-IV), Wechsler Adult
Intelligence Scale (WAIS-III), and Movement Assessment Battery for Children (Movement
ABC-2) and found delayed development in at least one area in 46.7% of patients. However only 15% showed cognitive defects, motor delayed was present in one third of patients, similarly to other studies [26,27]. In our cohort, motor and day living skills were the most affected areas.
Questionnaires such as the VABS-II are advantageous for patients and families as they can be completed at home avoiding time-consuming and stressful hospital visits. Other groups
[27] have used questionnaires [Adaptive Behavior Assessment System, 2nd edition (ABAS-
II), and Child Behavior Checklist (CBCL)] to assess 121 surgically treated patients. They found that speech delay was the most common problem and the overall rate of neurobehavioural abnormalities was 48%.
Detecting neurodevelopmental issues promptly is essential in order to provide appropriate support and rehabilitation. Our study supports the use of the VABS-II questionnaire as a screening tool for neurodevelopment in CHI patients.
Safe and effective therapeutic agents are needed for the most severe cases of diffuse CHI in order to avoid the inevitable consequences of subtotal pancreatectomy. Clinical trials are on- going to find new drugs (soluble glucagon, exendin 9-19, insulin receptor antibody) that provide a stable glucose profile and reduce the number of patients that require pancreatectomy.
Further information on the natural history of the disease in medically treated patients is required. Understanding the mechanisms of disease resolution and identifying markers that
98 could predict the likelihood of resolution or the risk of impaired neurodevelopment would be of great benefit for CHI patients and families and future research should be focused on these aspects. Ultimately, improving the long-term outcomes of CHI patients must be a priority for health professionals involved in the care of patients with CHI. Adverse outcomes can happen in all patients with hyperinsulinism irrespective of the management (medical or surgical), or of the form of the disease (focal or diffuse; transient or persistent). Identifying the condition and treating hyperinsulinaemic hypoglycaemia promptly and aggressively may have an improvement on the neurodevelopmental outcomes.
6.4 References
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