Journal of Perinatology (2011) 31, 567–570 r 2011 Nature America, Inc. All rights reserved. 0743-8346/11 www.nature.com/jp PERINATAL/NEONATAL CASE PRESENTATION A pathway to independence in newborns and with

S Shahawy1, NK Chan1, S Ellard2, E Young2, H Shahawy1, J Mace1, R Peverini1, R Chinnock1, PR Njolstad1, AT Hattersley2 and E Hathout1 1Division of Pediatric and Diabetes, Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, USA and 2Peninsula Medical School, Exeter, UK

testing for -associated antibodies and (4) family Permanent neonatal diabetes was previously assumed to require insulin diagnosed before 6 months of age. To our injection or infusion for life. Recently, permanent neonatal diabetes resulting knowledge, the first case in the United States of - from in the two protein subunits of the - treated diabetes caused by a in KCNJ11 was diagnosed at sensitive channel (Kir6.2 and SUR1) has proven to be successfully our center (Table 1, patient 6).1,5 Monogenic diabetes, caused by treatable with high doses of rather than insulin. Many patients mutations in key components of insulin secretion, is often with these mutations first develop in the nursery or intensive misdiagnosed as type 1 or . Therefore, all patients care unit. The awareness of the neonatolgist of this entity can have dramatic diagnosed with diabetes before 6 months of age should undergo effects on the long-term care and quality of life of these patients and their genetic testing for correct categorization of diabetes and its families. In this study, we present the experience of our center, highlighting recurrence risk9 as well as optimization of treatment and aspects relevant to neonatal diagnosis and treatment. maximizing the chance of insulin independence. Journal of Perinatology (2011) 31, 567–570; doi:10.1038/jp.2011.4

Keywords: diabetes; neonatal; permanent; monogenic Methods Data were collected retrospectively by chart review of patients diagnosed with diabetes before 6 months of age, and found to have Introduction a mutation associated with diabetes while receiving diabetes care at Permanent neonatal diabetes is persistent, insulin-requiring the Pediatric Diabetes Center, Loma Linda University. Testing for hyperglycemia presenting within the first 6 months of life.1–5 diabetes autoimmune antibodies (islet cell, glutamic acid The incidence has been estimated to range from 1 in 89 000 to 1 decarboxylase and insulin) was carried out at the time of diabetes in 260 000 live births. The most common cause is heterozygous diagnosis, other testing was concomitant with mutation detection. activating mutations in the KCNJ11, which encodes the Kir6.2 subunit of the adenosine triphosphate-sensitive . Clinical presentation is usually that of severe hyperglycemia or Results , but failure to thrive in the first few months of life can Eight patients had permanent neonatal diabetes and a mutation in be the main presenting feature in some patients. Many patients KCNJ11. In addition, one patient had a mutation in the insulin with mutations in the KCNJ11 gene can be switched from insulin gene, and another patient (with diabetes, renal cysts and kidney therapy to high doses of sulfonylureas with better diabetes control failure) had a mutation in the gene encoding the and improved quality of life.2,6–8 A diagnosis of monogenic factor hepatocyte nuclear factor-1b.10 Only patients with KCNJ11 diabetes caused by a mutation in KCNJ11 should be considered in mutations are presented in this review, which focuses on their the following cases: (1) diabetes diagnosed within the first clinical presentation and treatment course. These patients are 6 months of life, (2) infants born small for gestational age and briefly described below and summarized in Table 1. diagnosed with diabetes,3 (3) infants with diabetes and negative

Correspondence: Professor E Hathout, Division of Pediatric Endocrinology and Diabetes, Case Department of Pediatrics, Loma Linda University School of Medicine, 11175 Campus Street, Patient 1 CP A1120R, Loma Linda, CA 92354, USA. E-mail: [email protected] Patient 1 is a 20-year-old female diagnosed with type 1 diabetes at Received 26 August 2010; revised 10 December 2010; accepted 13 December 2010 the age of 9 weeks. She was born full term, but notably small for Insulin independence in newborns and infants with diabetes S Shahawy et al 568 gestational age (Table 1). She presented with ketoacidosis, had generalized encephalopathy, expressive language delay and motor been on insulin treatment for 20 years and was using an insulin delay. She has been cared for by her grandparents ever since. At pump up to the time of genetic testing. She has no family history 11 years of age, genetic testing was performed and she was found to of diabetes. Mild developmental delay had been noted throughout have the mutation V59M. The grandparents refused any change in her life. Genetic testing showed that she was heterozygous for the treatment for over a year for fear of new side effects, and only KCNJ11 mutation R201C. Identification of this mutation allowed recently agreed to start oral agents. At present, this patient is being insulin to be weaned and discontinued over 11 months with switched from insulin to glyburide with a current dose of glyburide incremental increases in the dose of an oral sulfonylurea agent of 1 mg kgÀ1 per day, and once-a-day basal insulin of 0.2 U kgÀ1. (glyburide). Patients 6 and 7 Patient 2 Patient 6 was a full term small for gestational age female baby. Patient 2 is a 9-month-old female, who was admitted to the She was diagnosed with ‘type 1’ diabetes at 2 weeks of age and neonatal intensive care unit at the age of 8 days because of the started on insulin injections. Testing for diabetes-related mutations hyperglycemia detected on screening in view of maternal diabetes. at 7 years of age revealed a mutation (R201H) in KCNJ11, which She was born full term, with birth weight and length below average was subsequently reported to cause sulfonylurea-treatable for age (Table 1). She was presumed to have type 1 diabetes and diabetes.1,5 The mother, who had a history of diabetes since started on an intravenous insulin drip, then subcutaneous basal infancy, was found to have the same mutation. Patient 6 was bolus insulin therapy. A family history was notable for her mother successfully transitioned from insulin to glyburide. Ongoing having early-onset type 1 diabetes. Mutation analysis of the attempts at modifying treatment in the mother are hampered KCNJ11 gene was undertaken after endocrinology consultation, because of her being an adult recipient of public aid. and the patient was found to be heterozygous for the missense mutation R201H. Her mother was subsequently tested and found to Patient 8 have the same mutation (patient 3 below). The patient was started Patient 3 above recently delivered a second small for gestational age on oral glyburide, (1.25 mg b.i.d) crushed and diluted in 2.5 ml female (patient 8) who was tested at 1 month of age for the water, and insulin was weaned with incremental increases of R201H mutation present in her mother and sister. She was glyburide every 2 weeks. asymptomatic at the time of genetic testing although her initial blood was 14.6 mmol lÀ1 (300 mg dlÀ1). Testing for diabetes Patient 3 autoimmune antibodies was negative. She was started on glyburide Patient 3 was diagnosed with type 1 diabetes at 4 months of age treatment without intervening insulin therapy, and her blood glucose when she presented with ketoacidosis. She remained on insulin remains adequately controlled to date (age 2 months). treatment for 17 years. When her daughter (patient 2) was diagnosed with diabetes at the age of 8 days, DNA testing was performed. Genetic testing identified the same mutation (R201H) Discussion as her daughter. This patient, currently 18 years of age, has not The relatively new entity of permanent neonatal diabetes due to been started on oral agents yet due to repeated teen activating mutations in the gene KCNJ11 is of particular relevance and poor compliance. to practicing neonatologists. Although KCNJ11 mutations are not the only cause of permanent neonatal diabetes, they are the most Patient 4 frequent, and account for 31% of cases in one series.3 These Hyperglycemia was detected in this male infant shortly after birth mutations impair the function of the adenosine triphosphate- following glucosuria on routine urinalysis in the nursery, and sensitive potassium channel preventing its physiological closure in insulin treatment was started. He was a term small for gestational response to glucose metabolism. Consequently, the pancreatic age baby. Genetic testing showed him to be heterozygous for a b cells cannot secrete insulin in response to glucose. Resultant novel missense mutation (N48I) in KCNJ11. He was successfully hyperglycemia mimics that of type 1 (insulin dependent) diabetes weaned off insulin and has maintained normal glucose without in its presentation with severe hyperglycemia, ketoacidosis or any medications at his current age of 20 months. failure to thrive. However, high doses of sulfonylurea agents can Patient 5 close the mutant adenosine triphosphate-sensitive potassium channel and allow insulin secretion, presumably in response to This 13-year-old-female was first diagnosed with type 1 diabetes at incretins. Many patients with permanent neonatal diabetes can be 6 weeks of age when she presented with ketoacidosis and was successfully switched from insulin injections to sulfonylurea started on insulin injections. At the age of 2 years, the patient therapy. This can be carried out over a few days in the inpatient developed both ataxic and right hemiplegic cerebral palsy, setting or a few weeks for patients at home.1 In our experience,

Journal of Perinatology Insulin independence in newborns and infants with diabetes S Shahawy et al 569

Table 1 Clinical characteristics of patients with diabetes caused by a mutation in the KCNJ11 gene

Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 Patient 6 Patient 7 Patient 8

Ages at diagnosis of diabetes/ 9 Weeks/20 8 Days/1 4 Months/17 11 Days/1 6 Weeks/11 2 Weeks/7 6 Months/23 5 Weeks/5 mutation years month years month years years years weeks Birth weight and length with 2.1 kg, <5% 2.6 kg, 5% 3.2 kg, 35% 2.7 kg, 10% 2.8 kg, 10% 2.4 kg, 5% NA 2.5 kg, 5% percentiles 45.7 cm, 5% 46 cm, <3% NA 45 cm, <5% NA NA 46 cm, <3% Family history of diabetes None Early onset Type 2 in Gestational in Type 2 in Early onset Early onset Early onset in in mother father mother grandfather in mother in daughter sister and mother Ketoacidosis history Positive Negative Positive Negative Positive Negative Negative Negative Neurological anomalies? Learning None None None Cognitive and None Mild cognitive None disability motor delay delay Diagnostic laboratories HbA1C (non-diabetic <6%) 8.2% 4.2% 8.6% 4.5% 9.0% 7.7% NA 3.7% C- (nmol/l; reference: <0.033 0.067 <0.033 0.233 NA 0.11 NA 0.9 0.167–0.666) Plasma glucose (mmol/l) 19.7 11.9 29.9 11.0 17.0 24.6 NA 14.6 Islet cell antibodies ICA512 Negative Negative NA Negative Negative Negative NA Negative Insulin autoantibodies Positive Positive NA Negative Negative Negative NA Negative GAD antibodies Negative Positive NA Negative Negative Negative NA Negative Insulin (U kgÀ1 per day; 1 0.5 1.2 0.1 1.2 0.9 NA 0 at diagnosis) Mutation p.Arg201Cys p.Arg201His p.Arg201His p.N48I p.V59 M p.Arg201His p.Arg201His p.Arg201His Glyburide (mg kgÀ1 per day) 1.1 0.3 0 0 0.8 0.6 0.3 0.6 Insulin independence Yes Yes No Yes No Yes No Yes Time to insulin independence 11 Months 1 Month 6 Months 2 Weeks 0

Abbreviations: GAD, glutamic acid decarboxylase; HbA1C, glycosylated hemoglobin A1C; NA, not available.

weekly increments of 25% increase in sulfonylurea dose and Neonatologists can have a crucial role in the timely testing of decrease in insulin dosages are well tolerated. A decrease in bolus infants for monogenic diabetes based on family history, low birth insulin therapy usually precedes weaning basal insulin dosing. weight and length percentiles, and early hyperglycemia. Some of Insulin independence is more achievable if sulfonylureas are our patients were diagnosed with KCNJ11 mutations despite introduced at a younger age.3 marginally positive diabetes auto-antibodies, which may be The diagnosis of neonatal diabetes is often first made in the maternally transmitted, hence positive antibody testing need not nursery or neonatal intensive care unit. Thus, the onus is on exclude patients from screening. Moreover, it is likely that many neonatologists to initiate appropriate referrals and genetic testing. insulin-dependent adults with diabetes have a mutation in KCNJ11 As noted with patient 8, oral agents can be started as soon as a and the potential of partial or complete insulin independence. This genetic diagnosis is established. The majority of mutations in offers an opportunity for both neonatologists and obstetricians to KCNJ11 are de novo in origin, and the parents do not have work with diabetologists toward optimum categorization and permanent neonatal diabetes. DNA testing is indicated in parents counseling regarding diabetes in patients and their families. with diabetes and encouraged in unaffected parents. Genetic testing for KCNJ11 mutations is available through Clinical Laboratory Improvement Amendments-certified laboratories in the United Conflict of interest States and similar laboratories in Europe. Information regarding The authors declare no conflict of interest. genetic testing laboratories can be found at Gene Tests (http:// www.ncbi.nlm.nih.gov/sites/GeneTests/lab/clinical_disease_id/ 293343?db¼genetests). In most instances, the health insurance of References the patients will cover the cost of genetic testing. Moreover, all 1 Sagen JV, Raeder H, Hathout E, Shehadeh N, Gudmundsson K, Baevre H et al. parents of patients with KCNJ11 mutations should be offered Permanent neonatal diabetes due to mutations in KCNJ11 encoding Kir6.2. Diabetes genetic counseling. 2004; 53: 2713–2718.

Journal of Perinatology Insulin independence in newborns and infants with diabetes S Shahawy et al 570

2 Pearson ER, Flechtner I, Njolstad PR, Malecki MT, Flanagan SE, Larkin B et al. 7 Codner E, Flanagan S, Ellard S, Garcia H, Hattersley AT. High-dose can Switching from insulin to oral sulfonylureas in patients with diabetes due to Kir.2 replace insulin therapy despite transitory diarrhea in early-onset diabetes caused by a mutations. N Engl J Med 2006; 355: 467–477. novel R201L Kir6.2 mutation. Diab Care 2005; 28: 758–759. 3 Murphy R, Ellard S, Hattersley AT. Clinical implications of a molecular genetic 8 Khupa J, Edghill EL, Nazim J, Sieradzki J, Ellard S, Hattersley AT et al. The classification of monogenic b-cell diabetes. Nature 2008; 4: 200–213. identification of a R201H mutation in KCNJ11, which encodes Kir6.2, and successful 4 Hattersley A, Bruining J, Shield J, Njolstad P, Donaghue K. The diagnosis transfer to sustained-release sulfonylurea therapy in a subject with neonatal diabetes: and management of monogenic diabetes in children. Pediatr Diab 2006; 7: evidence for heterogeneity of function among carriers of the R201H mutation. 352–360. Diabetalogia 2005; 48: 1029–1031. 5 Hathout E, Mace J, Bell GI, Njolstad PR. Treatment of hyperglycemia in a 7-year-old 9 De Leo´n DD, Stanley CA. Permanent neonatal diabetes. In: Pagon RA, Bird TC, child diagnosed with neonatal diabetes. Diab Care 2006; 29: 1458. Dolan CR, Stephens K (eds). GeneReviews [Internet]. University of Washington: 6 Zung A, Glaser B, Nimri R, Zadik Z. Glibenclamide treatment in Seattle (WA), 2008. permanent neonatal diabetes in a large cohort of French patients. Diabetes 10 Bingham C, Hattersley AT. Renal cysts and diabetes syndrome resulting from mutations 2004; 53: 2719–2722. in hepatocyte nuclear factor-1b. Nephrol Dial Transplant 2004; 19: 2703–2708.

Journal of Perinatology