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The purpose of this article is to determine the cause of Leber congenital amaurosis (LCA) in Chuuk state, Federated States of Micronesia (FSM). In this prospective observational case series, five patients with early-onset vision loss were examined in Chuuk state, FSM, during an ocular genetics visit to study the elevated incidence of microphthalmia. Because of their low vision these patients were incorrectly assumed to have microphthalmia. A complete ophthalmological exam established a clinical diagnosis of LCA. Candidate gene exons were sequenced with a targeted retinal dystrophy panel. Five subjects in three related families were diagnosed with LCA. All five were from Tonoas Island, within the Chuuk Lagoon, with ages ranging from 6 months to 16 years. DNA sequencing of affected individuals revealed a homozygous CRB1 NM_201253.3:c.3134del pathogenic variant, which was heterozygous in their parents. CRB1 genotypes were confirmed by a PCR restriction assay. We report identification of a founder pathogenic variant in CRB1 responsible for autosomal recessive LCA in this isolated community. This discovery will lead to appropriate recurrence risk counseling.

ImportanceFamilial exudative vitreoretinopathy (FEVR) is a nonsyndromic autosomal dominant retinal disorder commonly caused by variants in the FZD4 gene. This study investigates the potential role beyond ocular abnormalities for FZD4 gene variants in patients with FEVR.ObjectiveTo evaluate the role of FZD4 in symptoms beyond those associated with FEVR through a patient with biallelic variants in FZD4.Design, Setting, and ParticipantsThis case series included the DNA testing and phenotyping of 1 patient proband and her parents, combined with signaling assays, to determine the association of patient-derived compound heterozygous variants on FZD4 signaling and biologic function.Main Outcomes and MeasuresFZD4 genes were tested using next-generation sequencing and Sanger sequencing. Cell-based assays measured the effect of the variants on FZD4 signaling.ResultsThe proband presented with absent red reflexes from complete tractional retinal detachments diagnosed at 3 days of age and failed the newborn screening hearing test. Auditory brainstem response at 6 months of age showed bilateral mild to moderate high-frequency sensorineural hearing loss. The patient manifested developmental delays in speech and walking. Intravenous fluorescein angiography (IVFA) of the patient’s parents detected stage 1 FEVR. Genetic testing revealed 2 FZD4 variants in the patient, each variant found in 1 parent. Signaling assays confirmed that the presence of both variants was associated with significantly worse signaling activity compared with the heterozygous state.Conclusions and RelevanceResults of this case series suggest that extraocular syndromic FEVR was associated with FZD4 variants. The decrease in FZD4 signaling owing to the biallelic nature of the disease resulted in hearing deficits, developmental delays, and a more severe retinal phenotype.

The forkhead transcription factor FOXE3 is critical for vertebrate eye development. Recessive and dominant variants cause human ocular disease but the full range of phenotypes and mechanisms of action for the two classes of variants are unknown. We identified FOXE3 variants in individuals with congenital eye malformations and carried out in vitro functional analysis on selected alleles. Sixteen new recessive and dominant families, including six novel variants, were identified. Analysis of new and previously reported genetic and clinical data demonstrated a broad phenotypic range with an overlap between recessive and dominant disease. Most families with recessive alleles, composed of truncating and forkhead-domain missense variants, had severe corneal opacity (90%; sclerocornea in 47%), aphakia (83%) and microphthalmia (80%), but some had milder features including isolated cataract. The phenotype was most variable for recessive missense variants, suggesting that the functional consequences may be highly dependent on the type of amino acid substitution and its position. When assessed, aniridia or iris hypoplasia were noted in 89% and optic nerve anomalies in 60% of recessive cases, indicating that these defects are also common and may be underrecognized. In dominant pedigrees, caused by extension variants, normal eye size (96%), cataracts (99%) and variable anterior segment anomalies were seen in most, but some individuals had microphthalmia, aphakia or sclerocornea, more typical of recessive disease. Functional studies identified variable effects on the protein stability, DNA binding, nuclear localization and transcriptional activity for recessive FOXE3 variants, whereas dominant alleles showed severe impairment in all areas and dominant-negative characteristics.

International audience; Cyclic nucleotide-gated channel β1 (CNGB1) encodes the 240-kDa β subunit of the rod photoreceptor cyclic nucleotide-gated ion channel. Disease-causing sequence variants in CNGB1 lead to autosomal recessive rod-cone dystrophy/retinitis pigmentosa (RP). We herein present a comprehensive review and analysis of all previously reported CNGB1 sequence variants, and add 22 novel variants, thereby enlarging the spectrum to 84 variants in total, including 24 missense variants (two of which may also affect splicing), 21 nonsense, 19 splicing defects (7 at noncanonical positions), 10 small deletions, 1 small insertion, 1 small insertion-deletion, 7 small duplications, and 1 gross deletion. According to the American College of Medical Genetics and Genomics classification criteria, 59 variants were considered pathogenic or likely pathogenic and 25 were variants of uncertain significance. In addition, we provide further phenotypic data from 34 CNGB1-related RP cases, which, overall, are in line with previous findings suggesting that this form of RP has long-term retention of useful central vision despite the early onset of night blindness, which is valuable for patient counseling, but also has implications for it being considered a priority target for gene therapy trials.

Gillespie syndrome (GLSP) is characterized by bilateral symmetric partial aplasia of the iris presenting as a fixed and large pupil, cerebellar hypoplasia with ataxia, congenital hypotonia, and varying levels of intellectual disability. GLSP is caused by either biallelic or heterozygous, dominant-negative, pathogenic variants in ITPR1. Here, we present a 5-year-old male with GLSP who was found to have a heterozygous, de novo intronic variant in ITPR1 (NM_001168272.1:c.5935-17G > A) through genome sequencing (GS). Sanger sequencing of cDNA from this individual's fibroblasts showed the retention of 15 nucleotides from intron 45, which is predicted to cause an in-frame insertion of five amino acids near the C-terminal transmembrane domain of ITPR1. In addition, qPCR and cDNA sequencing demonstrated reduced expression of both ITPR1 alleles in fibroblasts when compared to parental samples. Given the close proximity of the predicted in-frame amino acid insertion to the site of previously described heterozygous, de novo, dominant-negative, pathogenic variants in GLSP, we predict that this variant also has a dominant-negative effect on ITPR1 channel function. Overall, this is the first report of a de novo intronic variant causing GLSP, which emphasizes the utility of GS and cDNA studies for diagnosing patients with a clinical presentation of GLSP and negative clinical exome sequencing.

Ocular Genetics at Wills Eye Hospital sees a wide range of rare disorders for accurate diagnosis. To demonstrate how focused consultation and genetic testing results in precise diagnoses, we investigated false diagnosis rates for patients referred with a diagnosis of Stargardt disease. This is a retrospective review of patients over a 3 year period referred to our Ocular Genetics clinic for possible Stargardt disease, or already holding a diagnosis of Stargardt disease. Results of diagnostic and genetic testing were compared to standard definition of Stargardt. Of 40 patients, 14 (35%) had been misdiagnosed. Four had non-Stargardt phenotype of which three had ABCA4 pathogenic variants with phenotypes inconsistent with Stargardt disease. Two of those with pathogenic ABCA4 variants were related. Nine had pathogenic variants in other different genes with overlapping features of Stargardt disease. One had Thioridazine maculopathy. Our study highlights the essential role of the subspecialty field of ocular genetics in obtaining accurate diagnoses for the delivery of correct counseling and interventional trial eligibility assessment.

Pigmentary retinal dystrophy and macular dystrophy have been previously reported in Heimler syndrome due to mutations in PEX1. Here we reported the ocular manifestations in Heimler syndrome due to mutations in PEX6.Medical records were reviewed to identify patient demographics, ophthalmic and systemic findings, and results of diagnostic testing including whole genome sequencing.Patient 1 is 12-year-old boy with a novel mutation c.275TG (p.Val92Gly) and known mutation c.1802GA (p.Arg601Gln) in PEX6. Patient 2 is a 7-year-old girl with the same known c.1802GA (p.Arg601Gln) mutation and another novel missense mutation c.296GT (p.Arg99Leu). Both patients exhibited a pigmentary retinopathy. Visual acuity in patient 1 was 20/80 and 20/25 following treatment of intraretinal cystoid spaces with carbonic anhydrase inhibitors, while patient 2 had visual acuity of 20/20 in both eyes without intraretinal cysts. Fundus autofluorescence showed a multitude of hyperfluorescent deposits in the paramacular area of both eyes. OCTs revealed significant depletion of photoreceptors in both patients and macular intraretinal cystoid spaces in one patient. Full field electroretinograms showed normal or abnormal photopic but normal scotopic responses. Multifocal electroretinograms were abnormal.Heimler syndrome due to biallelic PEX6 mutations demonstrates a macular dystrophy with characteristic fundus autofluorescence and may be complicated by intraretinal cystoid spaces.

Retinitis pigmentosa (RP) is a major cause of blindness that affects 1.5 million people worldwide. Mutations in cyclic nucleotide-gated channel β 1 (CNGB1) cause approximately 4% of autosomal recessive RP. Gene augmentation therapy shows promise for treating inherited retinal degenerations; however, relevant animal models and biomarkers of progression in patients with RP are needed to assess therapeutic outcomes. Here, we evaluated RP patients with CNGB1 mutations for potential biomarkers of progression and compared human phenotypes with those of mouse and dog models of the disease. Additionally, we used gene augmentation therapy in a CNGβ1-deficient dog model to evaluate potential translation to patients. CNGB1-deficient RP patients and mouse and dog models had a similar phenotype characterized by early loss of rod function and slow rod photoreceptor loss with a secondary decline in cone function. Advanced imaging showed promise for evaluating RP progression in human patients, and gene augmentation using adeno-associated virus vectors robustly sustained the rescue of rod function and preserved retinal structure in the dog model. Together, our results reveal an early loss of rod function in CNGB1-deficient patients and a wide window for therapeutic intervention. Moreover, the identification of potential biomarkers of outcome measures, availability of relevant animal models, and robust functional rescue from gene augmentation therapy support future work to move CNGB1-RP therapies toward clinical trials.

Heterozygous mutation in the PACS1 (phosphofurin acidic cluster sorting proteins 1) gene is a known cause of developmental delay, multiple congenital anomalies, dysmorphism, and ocular abnormalities. We present the case of an affected 10-year-old girl, conceived by assisted reproductive technology, who has ocular coloboma and findings characteristic of PACS1 mutation.

Introduction: The etiologies of congenital and developmental cataracts are diverse. Most are not syndromic and have no identifiable cause, thus creating a diagnostic dilemma. We investigated the utility of chromosomal microarray in identifying the etiology of isolated childhood cataracts. Methods: Patients with congenital or developmental cataracts without other associated abnormalities received a single-nucleotide polymorphism (SNP) microarray. copy number variations (CNV) and regions of homozygosity (ROH) were compared with previous literature reports and analyzed for candidate genes to assess pathogenicity. Results: We enrolled 37 patients. The mean age of the patient population was 10.98 years old. Nineteen patients (51.4%) had bilateral cataract. Positive family history was found in 11 patients (29.7%). Eighteen patients (48.7%) had a variant on microarray: 10 (27%) with CNV, 5 (13.5%) with ROH, and 3 patients (8.1%) with both CNV and homozygosity. In five patients (13.5%), we found a potentially causative cataract gene within an ROH. Discussion: There is a high rate of notable findings among the CNV and ROH detected. Three patients were homozygous in a region known to have a cataract gene suggesting a possible autosomal recessive disease. In those with CNV, segregation would help to affirm the pathogenicity of these regions and may lead to the identification of new genes. Conclusion: SNP microarray had a surprisingly high rate of notable findings in patients with isolated cataract and may reveal the opportunities for genetic counseling, lead to discovering new cataract genes and identify additional affected genes that could lead to other clinical abnormalities.

BACKGROUND AND OBJECTIVE: Knobloch syndrome is a genetic disorder defined by occipital defect, high myopia, and vitreoretinal degeneration. The authors studied retinal changes in patients with Knobloch syndrome using optical coherence tomography (OCT). PATIENTS AND METHODS: The authors report patients with Knobloch syndrome who received OCT testing during their care from 2011 to 2016. Diagnosis was based on high myopia, characteristic fundus, and occipital scalp or skull abnormalities with/without featureless irides and/or ectopia lentis. When available, diagnosis was confirmed by the detection of COL18A1 mutations. RESULTS: The authors studied eight eyes from five patients. Two eyes were excluded due to chronic retinal detachment. OCT findings included epiretinal membrane, peripapillary vitreoretinal traction with retinoschisis, absent or rudimentary foveal pits, mean macular thickness of 113.4 μm, poor lamination, retinal pigment epithelium (RPE) atrophy, photoreceptor depletion, and mean choroidal thickness of 168.5 μm with enlarged choroidal vessels. CONCLUSION: OCT findings in Knobloch syndrome include abnormal vitreoretinal traction, poor foveal differentiation, poor retinal lamination, retinal thinning, RPE attenuation, myopic choroidal thinning, and pachychoroid. [ Ophthalmic Surg Lasers Imaging Retina . 2019;50:e203–e210.]

Axenfeld–Rieger spectrum (ARS) includes the anterior segment abnormalities posterior embryotoxon, irido-corneal adhesions, corectopia, and other abnormalities of pupil size and shape. Glaucoma occurs in approximately 50% of affected children. It is often caused by mutations of FOXC1 or PITX2. Timing of expression and dosage of these transcription factors appear to be very critical in the development of the anterior segment. We report on one child with a deletion and another with a duplication involving 6p25, causing an anirdia-like phenotype. Classic anirdia is a pan-ophthalmic disorder caused by heterozygous mutations involving the paired homeobox gene PAX6 at 11p13. It is often associated with optic nerve hypoplasia, foveal hypoplasia, corneal pannus, nystagmus, and cataract. Microdeletion of 11p13 may be associated with life threatening Wilms tumor. Distinguishing these two syndromes has critical implications for prognosis and treatment. We demonstrate how chromosomal microarray can be instrumental in differentiating these phenotypes. © 2015 Wiley Periodicals, Inc.

Cystoid macular edema (CME) and non-leaking intraretinal cystoid spaces (ICS) have different pathophysiologic mechanisms.We report a patient with retinitis pigmentosa (RP) with ICS due to a mutation in the male germ cell-associated kinase (MAK) gene.A 41-year-old Ashkenazi Jewish male was referred for abnormal visual field revealed by regular optometric examination. His visual acuity was 20/20 in each eye. Dilated examination revealed typical finding of RP. Optical coherence tomography showed cystoid changes in each fovea. Photoreceptors were also degenerated. Intravenous fluorescein angiography showed no leakage. Genetic testing identified a homozygous mutation in the MAK gene: a 353-bp Alu insertion (K429insAlu).Mak regulates microtubule stability via phosphorylating RP1. Abnormal Mak may impact retinal photoreceptor ciliary length and subcompartmentalization. Mak is required for the survival of photoreceptors in mice. ICS has been reported in other ciliopathies. We report the first case of ICS due to mutation in MAK.

Emanuel syndrome is caused by a supernumerary der(22)t(11;22) and typically manifests with intellectual disability and craniofacial dysmorphism. Ocular abnormalities have infrequently been described. We report a 36-year-old man with severe intellectual disability, aphasia, and facial dysmorphism, with high myopia and juvenile open angle glaucoma (JOAG). Microarray analysis results included 47,XY,+der(22)t(11;22)(q23;q11.2), and a 269 kb deletion of 7q31.33(125,898,014-126,166,829). Two candidate genes were identified as possible etiologies for the ocular pathologies in our patient: a MFRP duplication on chromosome 11, which may play a role in high myopia and dysregulation of emmetropization, and a GRM8 deletion on chromosome 7, which may cause glutamate-induced excitotoxicity and therefore have a role in the development of JOAG, unrelated to the Emanuel syndrome genotype. We provide the first detailed description these ocular abnormalities in a patient with Emmanuel syndrome.

Purpose: Mutations in the ABCA4 gene result in a broad spectrum of severe retinal degeneration, including Stargardt macular dystrophy, fundus flavimaculatus, autosomal recessive retinitis pigmentosa, and cone-rod dystrophy. In addition to the detection of well-characterized mutations, genetic testing frequently yields novel variants of unknown significance. The purpose of this report is to describe an approach to aid in the assessment of genetic variants of unknown significance. Case report: We report an 11-year-old girl with Stargardt disease harboring novel compound heterozygous deletions of ABCA4 (c.850_857delATTCAAGA and c.6184_6187delGTCT). The pathogenicity of these variants was otherwise unknown. Both deletions introduce premature stop codons and are localized within the open reading frame of ABCA4. The c.850_857delATTCAAGA occurs early in the gene and leads to a significantly truncated protein of only 317 amino acids. The c.6184_6187delGTCT, is localized to the 3’ terminus of the ORF and results in removal of the last 161 out of 2,273 amino acids of ABCA4, including the VFVNFA motif, which has been shown to be critical in ABCA4 protein function. Homology-based protein modeling of ABCA4 harboring this deletion suggests significant alterations in the protein structure and function. Conclusions: Our analyses allowed us to classify novel variants in ABCA4 as being clearly loss-of-function mutations, and thus pathogenic variants. In cases of variants of unknown significance, appraising the protein structure-function consequences of genetic mutations using in silico tools may help to predict the clinical importance of variants of uncertain pathogenicity.

PURPOSE OF REVIEW To facilitate ophthalmologists' understanding on the cost of genetic testing in ocular disease, the complexities of insurance coverage and its impact on the availability of testing. RECENT FINDINGS Many insurance carriers address coverage for genetic testing in written clinical policies. They provide criteria for medically necessary testing. These policies mostly cover testing for individuals who are symptomatic and in whom testing will have a direct impact on medical treatment. In cases in which no treatments are currently available, other than research trials, patients may have difficulty in getting insurance coverage for genetic testing. SUMMARY Genetic testing for inherited eye diseases can be costly but has many benefits to patient care, including confirmation of a diagnosis, insight into prognostic information, and identification of associated health risks, inheritance patterns, and possible current and future treatments. As gene therapy advances progress, the availability for treatment in ocular diseases, coverage for genetic testing by third-party payers could increase on the basis of current clinical policies.