Clinical science The ophthalmic phenotype of IFT140-related ranges from isolated to syndromic congenital retinal dystrophy Inam N Bifari,1 Sahar M Elkhamary,2 Hanno J Bolz,3,4 Arif O Khan1

1Division of Pediatric ABSTRACT primary cilia. can be organ-specific, Ophthalmology, King Khaled Background Conorenal syndrome is a systemic skeletal such as polycystic kidney disease or Leber congeni- Eye Specialist Hospital, Riyadh, ciliopathy characterised by skeletal and renal findings tal amaurosis, or can be syndromic, such as Saudi Arabia 2 2Division of Radiology, and caused by biallelic mutations in the Bardet-Biedl or Alström syndrome. Sometimes King Khaled Eye Specialist intraflagellar transport 140 Chlamydomonas homologue children with syndromic ciliopathy can initially be Hospital, Riyadh, Saudi Arabia 3 (IFT140). Most studies have focused on syndromic thought to have only isolated Leber congenital Center for Human Genetics, features and are by non-ophthalmologists. We highlight amaurosis, before systemic manifestation becomes Bioscientia, Ingelheim, 34 Germany the ophthalmic phenotype. evident. The primary complex involves 4Institute of Human Genetics, Methods Retrospective consecutive case series hundreds of , and the number of recog- University of Cologne, Cologne, (2010–2014). nised ciliary and ciliopathy phenotypes con- Germany Results Twelve subjects with confirmed homozygous tinues to expand. fi fl Correspondence to mutations were identi ed (11 consanguineous families; Intra agellar transport 140 Dr Arif O Khan, Division of 7 boys; assessed at age 10 months to 20 years, average Chlamydomonas homologue (On-line Mendelian Pediatric Ophthalmology, King and median age 6.5 and 4 years). All were homozygous Inheritance in Man (MIM) *614620, IFT140) Khaled Eye Specialist Hospital, for the same IFT140 mutation (c.1990G>A; p. encodes a component of the ciliary intraflagellar PO Box 7191, Riyadh 11462, Glu664Lys) except one who was homozygous for transport complex A (IFT-A), which is involved in Saudi Arabia; [email protected] c.1541_1542delinsAA. All had poor vision and retrograde ciliary transport. Mutations in genes nystagmus since birth, with visual acuity after 5 years old responsible for IFT-A cause the conorenal syn- Received 25 July 2015 of hand motions or light perception. In early childhood, dromes Mainzer-Saldino syndrome (MIM Revised 23 August 2015 nine were noted to stare at lights, four were noted to #266920) and, less commonly, Jeune syndrome Accepted 26 August 2015 56 Published Online First have a happy demeanour, high hyperopia was typical, (MIM %208500). Mainzer-Saldino syndrome is 10 September 2015 and electroretinography was non-recordable. Fundus characterised by phalangeal cone-shaped epiphyses, appearance was grossly normal before the age of 1 year chronic renal disease, early-onset retinal dystrophy, but thereafter appeared dystrophic. Eight children had and developmental delay. Occasional features developmental delay, two had short stubby fingers, and include short stature, cerebellar ataxia, and hepatic one had renal disease, but four had no evident fibrosis. Jeune syndrome phenotypically overlaps extraocular disease, including one aged 18 years who with Mainzer-Saldino syndrome and has more than also had two older affected siblings in their twenties one recognised genetic cause. Jeune syndrome is who remained non-syndromic and were excelling characterised by cone-shaped epiphyses, shortened academically. ribs and a narrow chest, and short stature. Conclusions Recessive IFT140 mutations cause a Additional features include a variety of findings severe congenital retinal dystrophy with high hyperopia common to systemic ciliopathies such as renal and often early photophilia. Developmental delay is disease, retinal dystrophy, pancreatic cysts, hepatic common but not universal and not all patients have fibrosis, and developmental delay. obvious extraocular findings. The c.1990G>A mutation To date, 15 families with biallelic IFT140 muta- represents a founder effect or mutational hotspot on the tions have been reported in the literature, the Arabian Peninsula. majority of which had obvious syndromic pheno- types.356However, with the exception of two children from two Saudi families who we previ- 3 INTRODUCTION ously reported, the presenting ophthalmic pheno- IFT140 Ciliopathies are a category of disease due to type of children with -related retinopathy impaired function of cilia, evolutionarily highly has not been well characterised. The purpose of conserved hair-like organelles found in virtually all this report is to highlight ophthalmic features in a eukaryotic cells.1 There are two basic types of cilia cohort of Saudi children referred to a paediatric —motile cilia, found in certain organs such as the ophthalmologist for low vision and found to IFT140 respiratory tract or reproductive system, and harbour recessive mutations. primary cilia, which are present in virtually all ver- tebrate cells, functioning as cell sensors that relay METHODS information from the external environment during/ Institutional board approval was obtained for this after development (eg, guiding skeletal develop- report, part of a retrospective review of early- To cite: Bifari IN, ment) or between two compartments of the same childhood onset retinal dystrophies referred to a Elkhamary SM, Bolz HJ, cell (eg, between the inner and outer segments of paediatric ophthalmologist (AOK). This retrospect- et al. Br J Ophthalmol the photoreceptor cell).1 Most ciliopathies are ive consecutive case series (2010–2014) includes – 2016;100:829 833. related to mutations in genes that have roles in children referred for low vision, confirmed to have

Bifari IN, et al. Br J Ophthalmol 2016;100:829–833. doi:10.1136/bjophthalmol-2015-307555 829 Clinical science

early childhood onset retinal dysfunction, and found to harbour confirmed by multiplex ligation-dependent probe amplification, recessive mutations in IFT140. Electroretinography (ERG) was which also confirmed heterozygosity. done using standards of the International Society of Clinical All subjects had infantile nystagmus and poor vision noted Electrophysiology of Vision;7 chloral hydrate sedation was used since birth. Best recorded visual acuity was hand motion or light for children 1–4 years old. General medical history was recorded, perception. Eight subjects had developmental delay. Four sub- with specific questioning regarding the presence or absence of jects were clinically normal other than their retinal dystrophy at the following: neurodevelopmental delay, deafness, polydactyly, the time of last assessment (aged 10 months to 20 years). heart disease, kidney malformation, skeletal disease and obesity. During infancy, nine were noted to stare at lights and four were Neurodevelopmental delay was defined as delayed speech, social- noted to have a happy demeanour. All were hyperopic at the isation, and/or major motor landmarks by age 2 years.8 time of cycloplegic refraction except one older subject, who had All subjects who had genetic testing underwent next- keratoconus. All subjects who had hand X-rays had phalangeal generation sequencing of a panel of all known retinal dystrophy cone-shaped epiphyses. Further details are provided in table 1, genes (known by the end of 2013 or 2014, depending upon which also includes information regarding five additional clinic- when they attended the clinic) with confirmatory Sanger sequen- ally affected relatives (from two families) who did not undergo cing using previously described methods9 except for subject 8, genetic testing. The fundus appeared grossly normal in children who underwent direct IFT140 sequencing. Bioinformatic pro- under 1 year old, but had retinal pigment epithelial changes and grammes were used for evaluation of variants’ pathogenicity as arteriolar attenuation after 2 years old. In older children, per- previously described.910After next-generation sequencing, veri- ipheral mottling and sometimes peripheral punched-out chorior- fication of identified variants and segregation analyses were etinal lesions were seen. In those who underwent carried out by polymerase chain reaction amplification of the cor- autofluorescence and optical coherence tomography (OCT), responding exon, followed by Sanger sequencing. autofluorescence showed increased central macular signal and OCT showed loss of outer retinal structures. Clinical examples RESULTS are provided in figures 1–3. Eleven probands (12 affected subjects; 7 male) were identified, two of whom were previously reported.3 All harboured DISCUSSION the same homozygous IFT140 mutation (c.1990G>A; This cohort of 12 individuals (11 families) with confirmed p.Glu664Lys) except one (c.1541_1542delinsAA in subject 10). IFT140-related retinopathy and five clinically affected relatives There were no additional suspicious variants in other tested represents the largest such series to date. Retinopathy was con- genes on the next-generation gene panel except in subject 10a, genital and severe, with no individual who underwent electro- who was a heterozygous carrier for a nonsense mutation physiology having a recordable ERG. The fundus appeared (c.1189C>T, p.Gln397*) in ABHD12 (MIM *613599; grossly normal before 1 year old but appeared dystrophic after NM_001042472.2) and a complete deletion of NPHP1 (MIM 2 years of age. In early childhood, hyperopia, light staring and a *607100). The complete deletion of the NPHP1 gene was happy demeanour were recurrent. Developmental delay was

Table 1 Clinical summary Flat ID Sex Stare Mood Delay ODR ERG RNS (age, Va) Hands Comments

1 M Y Happy N N/A <2 years +4.50 (8 years, HM) CSPE MRI brain (2 years) and RFT/electrolytes (8 years) WNL 2 F Y Happy Y Y 4 years +6.00−1.25×180 (4 years, HM) N/A Infantile chest infections 3 M Y Happy Y Y <2 years +4.00 (1 years, poor fix) N/A – 4 F Y Normal N Y <2 years +12.50 (10 months, poor fix) N/A – 5 F Y Normal Y Y <2 years +5.50 (11 months, poor fix) Short Hypotonia fingers 6 M Y N/A N N/A 11 years +8.50−5.50×180 (11 years, LP) N/A – 7 M Y Happy Y Y <2 years +3.00−2.00×180 (3 years, poor fix) CSPE From Khan et al;3 hepatosplenomegaly 8 M Y Happy Y N/A <2 years +4.00−2.00×170 (1 year, poor fix) CSPE From Khan et al;3 RFT/electrolytes WNL (10 months); brain MRI WNL 9a F Y Normal Y Y 4 years N/A CSPE RFT/electrolytes WNL (8 years) 9b* F N/A Normal Y N/A <2 years +2.75 (1 year, poor fix) CSPE Abnormal teeth, narrow chest 9c* F N Normal Y Y N/A N/A CSPE Narrow chest; 5 years old 10a M N/A N/A N N/A 18 years +4.00−2.00×180 (18 years, HM) N/A Excels in school 10b* F N/A N/A N N/A 25 years +2.00 (25 years, HM) N/A Excels in school 10c* F N/A N/A N N/A 20 +4.00 (20 years, HM) N/A Excels in school, won academic award 10d* F N/A N/A N Y 2 years +8.00 (2 years, poor fix) N/A Nephew of others who are siblings 11a M N/A N/A Y N/A 20 years −9.00−6.00×115 (20 years, HM) CSPE, short Kidney transplant age 17 years; knee surgery; fingers keratoconus 11b F N/A N/A Y Y 6 years +4.00−1.00×180 (6 years, LP) N/A – All subjects had congenital nystagmus, poor vision and a grossly normal fundus appearance before 1 year old but dystrophic changes noted by 2 years old and the same homozygous IFT140 mutation (c.1990G>A; p.Glu664Lys; NM_014714.3) except subject 10 (c.1541_1542delinsAA). Lowercase letters with a given ID number indicates same family. *Indicates did not have genetic testing. CSPE, cone-shaped phalangeal epiphyses; DELAY, presence/absence of developmental delay; ERG, electroretinography; F, female; fix, fixation; HM, hand motions; LP, light perception; M, male; N, No; N/A, not available; ODR, presence/absence of oculo-digital reflex in childhood; RNS, cycloplegic refraction; RFT, renal function test; STARE, presence/absence of photophilia in infancy; Va, best-corrected vision; Y, Yes; WNL, within normal limits.

830 Bifari IN, et al. Br J Ophthalmol 2016;100:829–833. doi:10.1136/bjophthalmol-2015-307555 Clinical science

Figure 1 Subject 1: Retinal images are of the right eye; the left eye is not shown but was similar. (A) Fundus photograph of the right eye shows retinal pigment epithelial mottling and arteriolar attenuation. (B) Autofluorescence reveals increased signal in the central macula. (C) Optical coherence tomography reveals loss of outer retinal layers with relative preservation of inner retinal layers. (D) Cone-shaped phalangeal epiphyses can be appreciated on plain X-ray of the hands. common and some children had frank skeletal or kidney disease; fact that almost all of the children in our series did not have however, there were individuals for whom the ophthalmic evident renal disease. Schmidts and colleagues6 reported six phenotype seemed clinically isolated. All families except one har- European patients from six families with compound heterozy- boured the same homozygous missense IFT140 mutation, sug- gous missense and/or nonsense IFT140 mutations; all had evi- gesting it is a founder effect or mutational hotspot in the region. dence for renal and skeletal disease and most appeared to have Almost all of the 13 other reported families with biallelic retinopathy, although the ophthalmic phenotype was not care- IFT140 mutations were obviously syndromic and ophthalmic fully assessed. phenotypic details were limited. Perrault and colleagues5 In our series, the retinal dystrophy associated with a homozy- described seven families with compound heterozygous or homo- gous IFT140 mutation was universally congenital and severe zygous missense, splice or nonsense mutations. All had phalan- and associated with early childhood hyperopia. The early child- geal cone-shaped epiphyses, and many had renal disease, hood phenotype of grossly normal fundus, high hyperopia and developmental delay and/or short stature. All had a documented non-recordable ERG with or without neurodevelopmental delay diagnosis of retinal dystrophy except two children from two overlaps with classic Leber congenital amaurosis.11 Infantile families for whom the ophthalmic phenotype was not assessed. photophilia was a recurrent observation in our series and was There were two Saudi Arabian families in that series, and both also noted in one of the two Saudi families reported by Perrault harboured the same homozygous recessive missense mutation and colleagues.5 Photophilia has been previously documented as we report. Interestingly, those were the only two families in that recurrent for children with early childhood retinal dystrophies – series without overt childhood renal disease, consistent with the from biallelic mutations in RPE65, LRAT and PRPH2.12 14 Another recurrent observation we noted was a happy early childhood demeanour, an observation we have made before.3 Ours is the first series to document fundus appearance, auto- fluorescence and OCT for biallelic IFT140 mutations. In patients for whom these images were obtained, there was arteri- olar narrowing and slight retinal pigment epithelium discolour- ation in the macula after 2 years old, peripheral mottling and sometimes punched out chorioretinal atrophy in older children, central macular increased signal by autofluorescence, and loss of outer retinal structures with relative preservation of inner struc- tures by OCT. A notable finding in our series is that individuals with IFT140-related retinopathy can be clinically non-syndromic, even as young adults. This was suggested by Perrault and collea- Figure 2 Subject 4: (A) At 1 year old, photophilia is evident. (B) At gues in a 1-year-old Saudi girl5 and by us in a 10-month-old 2 years of age, eye rubbing (the oculo-digital sign) became common. boy3 (subject 8 in the current report), but those children were

Bifari IN, et al. Br J Ophthalmol 2016;100:829–833. doi:10.1136/bjophthalmol-2015-307555 831 Clinical science

Figure 3 (Subject 10): Retinal images are of the left eye; the right eye is not shown but was similar. (A) Fundus photograph of the left eye shows retinal pigment epithelial mottling and arteriolar attenuation. (B) Mottling and outer retinal atrophy is more evident in the periphery, including occasional ‘punched-out’ lesions. (C) Autofluorescence shows a ring of increased signal in the central macula encircling the foveal area. There is also increased signal elsewhere in the posterior pole. (D and E) Optical coherence tomography reveals loss of outer retinal layers with relative preservation of inner retinal layers. still young at the time of assessment. In the current series, Correction notice This article has been corrected since it was published Online including affected relatives, 10/17 had developmental delay, First. Bold formatting has been removed from Table 1. 8/17 had evident skeletal disease and 1/17 had clinical renal Contributors Substantial contributions to the conception or design of the work disease. In one family three clinically affected siblings, currently (AOK and HJB); or the acquisition, analysis, or interpretation of data for the work (INB, SME, HJB and AOK); drafting the work or revising it critically for important 18, 20 and 25 years old, have excelled at school, with one of intellectual content (INB, SME, HJB and AOK); final approval of the version to be them winning a national academic prize. All six clinically published (INB, SME, HJB and AOK); and agreement to be accountable for all affected children who had hand X-rays had phalangeal cone- aspects of the work in ensuring that questions related to the accuracy or integrity of shaped epiphyses. In the series by Perrault and colleagues,5 all any part of the work are appropriately investigated and resolved (INB, SME, HJB and 10 individuals who had X-rays also had cone-shaped epiphyses, AOK). The corresponding author had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data whether or not there was an obvious skeletal phenotype. analysis. Although only one child in our series had clinical renal disease, Competing interests HJB is an employee of the company Bioscientia. it is important to note that variable expressivity for ciliopathies is a recognised phenomenon and that most children in this Patient consent Obtained. retrospective study did not have a careful work-up for subclin- Ethics approval KKESH IRB. ical renal disease. Provenance and peer review Not commissioned; externally peer reviewed. There are limitations to our retrospective series. Data collec- Addendum While this article was in revision, the following relevant article was tion was limited by what was available in medical records and published: Xu M, Yang L, Wang F, et al. Mutations in human IFT140 cause not all individuals had the same degree of clinical phenotypic non-syndromic retinal degeneration. Hum Genet Published Online First: 28 Jul 2015. assessment. Similarly, not all children had the same degree of doi:10.1007/s00439-015-1586-x ancillary investigations, for example, hand X-rays or renal func- tion testing. However, we are able to define the ophthalmic IFT140 REFERENCES phenotype associated with a homozygous mutation and 1 Berbari NF, O’Connor AK, Haycraft CJ, et al. The primary cilium as a complex show that it can present without clinically evident extraocular signaling center. Curr Biol 2009;19:R526–35. manifestations, overlapping with Leber congenital amaurosis. 2 Mockel A, Perdomo Y, Stutzmann F, et al. Retinal dystrophy in Bardet- IFT140 should be considered a candidate gene in children with Biedl syndrome and related syndromic ciliopathies. Prog Retin Eye Res – severe congenital retinal dystrophy, especially if there is a skel- 2011;30:258 74. IFT140 3 Khan AO, Bolz HJ, Bergmann C. Early-onset severe retinal dystrophy as the initial etal or renal phenotype. Because mutations can also presentation of IFT140-related skeletal ciliopathy. J AAPOS 2014;18:203–5. cause apparent Leber congenital amaurosis, the gene should be 4 Khan AO, Bifari IN, Bolz HJ. Ophthalmic features of children not yet diagnosed with included on Leber congenital amarosis gene panels. Given the Alstrom syndrome. Ophthalmology 2015;122:1726–27.e2. nature of IFT140, it seems prudent that children identified with 5 Perrault I, Saunier S, Hanein S, et al. Mainzer-Saldino syndrome is a ciliopathy caused by IFT140 mutations. Am J Hum Genet 2012;90:864–70. disease-causing mutations should have systemic follow-up 6 Schmidts M, Frank V, Eisenberger T, et al. Combined NGS approaches identify whether or not they have apparent extraocular disease, particu- mutations in the intraflagellar transport gene IFT140 in skeletal ciliopathies with larly for renal function. early progressive kidney disease. Hum Mutat 2013;34:714–24.

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