Search

To investigate baseline mesopic microperimetry (MP) and spectral domain optical coherence tomography (OCT) in the Rate of Progression in USH2A-related Retinal Degeneration (RUSH2A) study.Natural history study METHODS: Setting: 16 clinical sites in Europe and North AmericaStudy Population: Participants with Usher syndrome type 2 (USH2) (N = 80) or autosomal recessive nonsyndromic RP (ARRP) (N = 47) associated with biallelic disease-causing sequence variants in USH2AObservation Procedures: General linear models were used to assess characteristics including disease duration, MP mean sensitivity and OCT intact ellipsoid zone (EZ) area. The associations between mean sensitivity and EZ area with other measures, including best corrected visual acuity (BCVA) and central subfield thickness (CST) within the central 1 mm, were assessed using Spearman correlation coefficients.Mean sensitivity on MP; EZ area and CST on OCT.All participants (N = 127) had OCT, while MP was obtained at selected sites (N = 93). Participants with Usher syndrome type 2 (USH2, N = 80) and nonsyndromic autosomal recessive Retinitis Pigmentosa (ARRP, N = 47) had the following similar measurements: EZ area (median (interquartile range [IQR]): 1.4 (0.4, 3.1) mmLonger disease duration correlated with more severe retinal structure and function abnormalities, and there were associations between MP and OCT metrics. Monitoring changes in retinal structure-function relationships during disease progression will provide important insights into disease mechanism in USH2A-related retinal degeneration.

Unilateral cataract can cause pediatric vision impairment. Although the majority of unilateral cataracts are idiopathic in nature, genetic causes have been reported. We present the case of a 4-week-old child of nonconsanguineous parents who was affected with unilateral cataract. Whole-genome sequencing using DNA extracted from blood and the lens epithelial cells following cataract surgery revealed two presumed pathogenic variants in the TRPM1 gene, the founding member of the melanoma-related transient receptor potential (TRPM) subfamily. TRPM1 is responsible for regulating cation influx to hyperpolarized retinal ON bipolar cells, and mutations in this gene are a major cause of autosomal recessive congenital stationary night blindness (CSNB). Electroretinography revealed findings consistent with CSNB, a phenotype that was not initially suspected, and which would likely have been missed without genome sequencing. It remains unclear whether the TRPM1 variants are associated with the cataract phenotype.

To determine the validity of the validate the adult patient-reported outcome measure tools, the Michigan Retinal Degeneration Questionnaire (MRDQ) and Michigan Vision-Related Anxiety Questionnaire (MVAQ), in adolescent patients with inherited retinal diseases (IRDs). Ninety-one adolescent patients diagnosed with IRDs were recruited at the Hospital for Sick Children (University of Toronto) and the Kellogg Eye Center (University of Michigan). The patients were administered the MRDQ, MVAQ, and Patient Health Questionnaire-4 (PHQ-4). Test-retest variability was assessed in eighteen patients within 14 days of the initial administration. Adolescent responses were analyzed for validity and reliability. As a further validation step, comparisons were made to adult data from the original MRDQ and MVAQ studies to ensure consistency in response ranges. The existing MRDQ and MVAQ content and format could accurately detect the impact of IRD on activities of daily living in adolescents with IRDs. No floor/ceiling effects were identified, test-retest reliability was established (r = 0.73–0.86), and no items were excluded after differential item functioning analysis. Domain and trait associations with visual acuity and IRD phenotypes were similar between adolescents and adults. The MRDQ and MVAQ are psychometrically validated questionnaires for which we have shown validity for use in adolescent patients with IRDs.

Background Lafora disease (LD) is a neurodegenerative disorder featuring action and stimulus-sensitive myoclonus, epilepsy, and cognitive deterioration. Mutations in the EPM2A/EPM2B genes classically prove causative for the disease in most cases. Since full-field electroretinogram (ffERG) may reveal early-stage changes in a wide spectrum of diseases, we aimed to evaluate retinal cones and rods dysfunction in a cohort of Italian LD patients. Methods Patients with genetically confirmed LD were recruited and subjected to ffERG analysis following the International Society for Clinical Electrophysiology of Vision (ISCEV) protocol. Results Six patients aged between 13 and 26 years (mean 19.5 years) were included. The mean age at disease onset was 12.5 years with a mean disease duration of 7 years. The ffERG analysis revealed a global mild to severe generalized cones dysfunction in all patients. Linear correlation was identified between disease stage and the degree of cones and rods dysfunction, as well as between the type of mutation and the cones and rods dysfunction. Conclusions This study brings further evidence of early retinal alterations in LD patients. The cones and rods dysfunction grade is related to disease duration. The ffERG is an important tool to determine the disease stage, allowing to evaluate either natural or treatment-related disease progression in a minimally invasive way.

Highlights • KCNV2-associated retinopathy is a slowly progressive disease with early retinal changes, which are predominantly symmetric between eyes. • Disease course can be unpredictable and may severely affect children and young adults. • Findings suggest a potential window for intervention until 40 years of age, albeit with variability between patients due to macular atrophy., Purpose To describe the detailed retinal phenotype of KCNV2-associated retinopathy. Study design Multicenter international retrospective case series. Methods Review of retinal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT), including qualitative and quantitative analyses. Results Three distinct macular FAF features were identified: (1) centrally increased signal (n = 35, 41.7%), (2) decreased autofluorescence (n = 27, 31.1%), and (3) ring of increased signal (n = 37, 44.0%). Five distinct FAF groups were identified based on combinations of those features, with 23.5% of patients changing the FAF group over a mean (range) follow-up of 5.9 years (1.9-13.1 years). Qualitative assessment was performed by grading OCT into 5 grades: (1) continuous ellipsoid zone (EZ) (20.5%); (2) EZ disruption (26.1%); (3) EZ absence, without optical gap and with preserved retinal pigment epithelium complex (21.6%); (4) loss of EZ and a hyporeflective zone at the foveola (6.8%); and (5) outer retina and retinal pigment epithelium complex loss (25.0%). Eighty-six patients had scans available from both eyes, with 83 (96.5%) having the same grade in both eyes, and 36.1% changed OCT grade over a mean follow-up of 5.5 years. The annual rate of outer nuclear layer thickness change was similar for right and left eyes. Conclusions KCNV2-associated retinopathy is a slowly progressive disease with early retinal changes, which are predominantly symmetric between eyes. The identification of a single OCT or FAF measurement as an endpoint to determine progression that applies to all patients may be challenging, although outer nuclear layer thickness is a potential biomarker. Findings suggest a potential window for intervention until 40 years of age.

Vitamin A plays a crucial role in rod phototransduction, with deficient levels manifesting as night blindness. Animal models have demonstrated bone dysplasia in the setting of hypovitaminosis A. We present a rare case of bony overgrowth leading to bilateral compressive optic neuropathy, combined with outer retinopathy, in a paediatric patient secondary to isolated vitamin A deficiency.A single case report was conducted from Toronto, Canada.A 12-year-old boy with known autism spectrum disorder presented with a 9-month history of progressive painless vision loss. Vision was 20/300 and hand motion in the right and left eye, respectively. Fundus photography demonstrated bilateral optic atrophy and yellow lesions notably in the right eye far periphery. Optical coherence tomography (OCT) imaging demonstrated thinning of the retinal nerve fibre layer, alterations in the ellipsoid zone, as well as retinal pigment epithelium deposits. Computed tomography imaging demonstrated sphenoid bone thickening with narrow optic canals and moderate optic atrophy bilaterally. Full-field electroretinogram (ERG) demonstrated mildly reduced dark adapted (DA) 0.01 b-wave amplitudes and electronegative configuration of DA 3.0 and DA 10.0 ERG; the light adapted ERGs were normal. The patient was treated with pulse vitamin A therapy. Subsequently, the DA ERG normalized, outer retinal changes reversed and vision stabilised; no surgical intervention was conducted.This case represents a rare presentation of compressive optic neuropathy with concomitant outer retinopathy secondary to isolated vitamin A deficiency. Despite improvement in outer retinal integrity on OCT imaging and ERG testing results following vitamin A supplementation, no functional improvement was obtained due to severe optic atrophy.

Non-syndromic retinitis pigmentosa (NSRP) is a clinically and genetically heterogeneous group of disorders characterized by progressive degeneration of the rod and cone photoreceptors, often leading to blindness. The evolving association of syndromic genes to cause NSRP and the increasing role of intronic variants in explaining missing heritability in genetic disorders present challenges in establishing conclusive clinical and genetic diagnoses. This study sought to identify and validate the causative genetic variant(s) in a 13-year-old male initially diagnosed with NSRP. Genome sequencing identified a pathogenic missense variant in MVK [NM_000431.3:c.803Tgt;C (p.Ile268Thr)], in trans with a novel intronic variant predicted to create a new donor splice site (c.768+71Cgt;A). Proband cDNA analysis confirmed the inclusion of the first 68 base pairs of intron 8 that resulted in a frameshift in MVK (r.768_769ins[768+1_768+68]) and significantly reduced the expression of reference transcript (17.6%). Patient re-phenotyping revealed ataxia, cerebellar atrophy, elevated urinary mevalonate and LTEsub4/sub, in keeping with mild mevalonic aciduria and associated syndromic retinitis pigmentosa. Leakage of reference transcript likely explains the milder phenotype observed in our patient. This is the first association of a deep intronic splice variant to cause MVK-related disorder. This report highlights the importance of variant validation and patient re-phenotyping in establishing accurate diagnosis in the era of genome sequencing.

Purpose To investigate genetics, electrophysiology, and clinical course of KCNV2-associated retinopathy in a cohort of children and adults. Study design This was a multicenter international clinical cohort study. Methods Review of clinical notes and molecular genetic testing. Full-field electroretinography (ERG) recordings, incorporating the international standards, were reviewed and quantified and compared with age and recordings from control subjects. Results In total, 230 disease-associated alleles were identified from 117 patients, corresponding to 75 different KCNV2 variants, with 28 being novel. The mean age of onset was 3.9 years old. All patients were symptomatic before 12 years of age (range, 0-11 years). Decreased visual acuity was present in all patients, and 4 other symptoms were common: reduced color vision (78.6%), photophobia (53.5%), nyctalopia (43.6%), and nystagmus (38.6%). After a mean follow-up of 8.4 years, the mean best-corrected visual acuity (BCVA ± SD) decreased from 0.81 ± 0.27 to 0.90 ± 0.31 logarithm of minimal angle of resolution. Full-field ERGs showed pathognomonic waveform features. Quantitative assessment revealed a wide range of ERG amplitudes and peak times, with a mean rate of age-associated reduction indistinguishable from the control group. Mean amplitude reductions for the dark-adapted 0.01 ERG, dark-adapted 10 ERG a-wave, and LA 3.0 30 Hz and LA3 ERG b-waves were 55%, 21%, 48%, and 74%, respectively compared with control values. Peak times showed stability across 6 decades. Conclusion In KCNV2-associated retinopathy, full-field ERGs are diagnostic and consistent with largely stable peripheral retinal dysfunction. Report 1 highlights the severity of the clinical phenotype and established a large cohort of patients, emphasizing the unmet need for trials of novel therapeutics., Highlights • The current study established the largest and most characterized cohort of molecularly confirmed patients with KCNV2-associated retinopathy. • Report 1 highlights the genetic background, evidence of electroretinography stability over a broad age range, and the severe phenotype of the disease.

Certain combinations of common variants in exon 3 of OPN1LW and OPN1MW, the genes encoding the apo-protein of the long- and middle-wavelength sensitive cone photoreceptor visual pigments in humans, induce splicing defects and have been associated with dyschromatopsia and cone dysfunction syndromes. Here we report the identification of a novel exon 3 haplotype, G-C-G-A-T-T-G-G (referring to nucleotide variants at cDNA positions c.453, c.457, c.465, c.511, c.513, c.521, c.532, and c.538) deduced to encode a pigment with the amino acid residues L-I-V-V-A at positions p.153, p.171, p.174, p.178, and p.180, in OPN1LW or OPN1MW or both in a series of seven patients from four families with cone dysfunction. Applying minigene assays for all observed exon 3 haplotypes in the patients, we demonstrated that the novel exon 3 haplotype L-I-V-V-A induces a strong but incomplete splicing defect with 3–5% of residual correctly spliced transcripts. Minigene splicing outcomes were similar in HEK293 cells and the human retinoblastoma cell line WERI-Rb1, the latter retaining a cone photoreceptor expression profile including endogenous OPN1LW and OPN1MW gene expression. Patients carrying the novel L-I-V-V-A haplotype presented with a mild form of Blue Cone Monochromacy or Bornholm Eye Disease-like phenotype with reduced visual acuity, reduced cone electroretinography responses, red-green color vision defects, and frequently with severe myopia.

PURPOSE: Retinoblastoma is an aggressive pediatric eye cancer. Patient-reported outcome measures reveal important insights into how patients perceive their own health. Currently, there is no widely used or validated measure for assessment of retinoblastoma outcomes. The purpose of this research was to uncover which treatment outcomes that retinoblastoma survivors and their parents value, to inform the development of a future measure. METHODS: This qualitative, cross-sectional study included retinoblastoma survivors age 6 years and older and parents of retinoblastoma survivors. Participants who did not demonstrate fluency in English were excluded. Study participants participated in semistructured interviews or focus groups, either in person at The Hospital for Sick Children, Toronto, Canada, or through secure videoconference, between March 3, 2019, and January 25, 2020. Iterative rounds of opening coding, codebook development, and coresearcher analysis were used to identify key emergent themes and subthemes. RESULTS: Seventeen adults participated in six focus groups. Nine pediatric survivors participated in individual interviews. Four common themes emerged from all participant groups: (1) definition of treatment success, (2) enucleation—acceptance and challenges, (3) treatment outcomes to measure, and (4) need for outcome reporting. An additional, unique theme was identified in all pediatric discussions: worries and coping mechanisms. Treatment outcomes deemed valuable were related to the following domains: psychosocial outcomes, daily functioning, functional vision, retinoblastoma education, cosmetic outcomes, and secondary eye conditions. CONCLUSION: This study represents the first stage in the development of a retinoblastoma-specific patient-reported outcome measure. The findings reveal insight into what outcomes are valued by survivors after treatment and offer promise to improve outcomes assessment for retinoblastoma.

Purpose Determining the role of DYNC2H1 variants in nonsyndromic inherited retinal disease (IRD). Methods Genome and exome sequencing were performed for five unrelated cases of IRD with no identified variant. In vitro assays were developed to validate the variants identified (fibroblast assay, induced pluripotent stem cell [iPSC] derived retinal organoids, and a dynein motility assay). Results Four novel DYNC2H1 variants (V1, g.103327020_103327021dup; V2, g.103055779A>T; V3, g.103112272C>G; V4, g.103070104A>C) and one previously reported variant (V5, g.103339363T>G) were identified. In proband 1 (V1/V2), V1 was predicted to introduce a premature termination codon (PTC), whereas V2 disrupted the exon 41 splice donor site causing incomplete skipping of exon 41. V1 and V2 impaired dynein-2 motility in vitro and perturbed IFT88 distribution within cilia. V3, homozygous in probands 2–4, is predicted to cause a PTC in a retina-predominant transcript. Analysis of retinal organoids showed that this new transcript expression increased with organoid differentiation. V4, a novel missense variant, was in trans with V5, previously associated with Jeune asphyxiating thoracic dystrophy (JATD). Conclusion The DYNC2H1 variants discussed herein were either hypomorphic or affecting a retina-predominant transcript and caused nonsyndromic IRD. Dynein variants, specifically DYNC2H1 variants are reported as a cause of non syndromic IRD.

S-adenosylhomocysteine hydrolase deficiency due to pathologic variants in AHCY gene is a rare neurometabolic disease for which no eye phenotype has been documented. Pathologic variants in CRB1 gene...

To report the clinical and novel electrophysiological features in a child with POLG-related sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO). The proband, a male child of Indian descent, underwent serial systemic and ophthalmological evaluations from birth until 14 years of age. Eye examinations included visual acuity and extraocular movement assessments, fundus photography, spectral domain optical coherence tomography and full-field electroretinography (ERG). Detailed genetic testing was also performed. The child carried a homozygous mutation in POLG (c.911T > G/p.Leu304Arg) and manifested systemic features such as seizures, headaches, areflexia, hypotonia, myopathy and vomiting. The child’s distance visual acuity was 0.50 and 0.40 LogMAR in the right and left eyes, respectively. Bilateral ophthalmoplegia and ptosis were observed at 5 years of age. The dark-adapted (DA) ERG responses to 2.29 cd s m−2 and 7.6 cd s m−2 stimuli showed a markedly reduced b/a ratio; an electronegative configuration was noted to a DA 7.6 ERG. This is the first documented case of an electronegative ERG in a POLG-related disorder consistent with generalized rod ON-bipolar dysfunction. The rest of the proband’s systemic and ophthalmological features were consistent with SANDO but some features overlapped with other POLG-related disorders such as Alpers–Huttenlocher syndrome and autosomal dominant progressive external ophthalmoplegia demonstrating the wide phenotypic overlap expected due to POLG mutations.

Background: Axenfeld-Rieger syndrome is characterized by a spectrum of anterior segment dysgenesis involving neural-crest-derived tissues, most commonly secondary to mutations in the transcription ...

PURPOSE. The purpose of this study was to compare the natural history of visual function change in cohorts of patients affected with retinal degeneration due to biallelic variants in Bardet-Biedl syndrome genes: BBS1 and BBS10. METHODS. Patients were recruited from nine academic centers from six countries (Belgium, Canada, France, New Zealand, Switzerland, and the United States). Inclusion criteria were: (1) female or male patients with a clinical diagnosis of retinal dystrophy, (2) biallelic disease-causing variants in BBS1 or BBS10, and (3) measures of visual function for at least one visit. Retrospective data collected included genotypes, age, onset of symptoms, and best corrected visual acuity (VA). When possible, data on refractive error, fundus images and autofluorescence (FAF), optical coherence tomography (OCT), Goldmann kinetic perimetry (VF), electroretinography (ERG), and the systemic phenotype were collected. RESULTS. Sixty-seven individuals had variants in BBS1 (n = 38; 20 female patients and 18 male patients); or BBS10 (n = 29; 14 female patients and 15 male patients). Missense variants were the most common type of variants for patients with BBS1, whereas frameshift variants were most common for BBS10. When ERGs were recordable, rod-cone dystrophy (RCD) was observed in 82% (23/28) of patients with BBS1 and 73% (8/11) of patients with BBS10; cone-rod dystrophy (CORD) was seen in 18% of patients with BBS1 only, and cone dystrophy (COD) was only seen in 3 patients with BBS10 (27%). ERGs were nondetectable earlier in patients with BBS10 than in patients with BBS1. Similarly, VA and VF declined more rapidly in patients with BBS10 compared to patients with BBS1. CONCLUSIONS. Retinal degeneration appears earlier and is more severe in BBS10 cases as compared to those with BBS1 variants. The course of change of visual function appears to relate to genetic subtypes of BBS.

BACKGROUND: Atypical Usher syndrome (USH) is poorly defined with a broad clinical spectrum. Here we characterize the clinical phenotypic of disease caused by variants in CEP78, CEP250, ARSG, and ABHD12. MATERIALS AND METHODS: Chart review evaluating demographic, clinical, imaging, and genetic findings of 19 patients from 18 families with a clinical diagnosis of retinal disease and confirmed disease causing variants in CEP78, CEP250, ARSG, or ABHD12. RESULTS: CEP78-related disease included sensorineural hearing loss (SNHL) in 6/7 patients and demonstrated a broad phenotypic spectrum including: vascular attenuation, pallor of the optic disc, intraretinal pigment, retinal pigment epithelium mottling, areas of mid-peripheral hypo-autofluorescence, outer retinal atrophy, mild pigmentary changes in the macula, foveal hypo-autofluorescence, and granularity of the ellipsoid zone. Nonsense and frameshift variants in CEP250 showed mild retinal disease with progressive, non-congenital SNHL. ARSG variants resulted in a characteristic pericentral pattern of hypo-autofluorescence with one patient reporting non-congenital SNHL. ABHD12 related disease showed rod-cone dystrophy with macular involvement, early and severe decreased best corrected visual acuity, and non-congenital SNHL ranging from unreported to severe. CONCLUSIONS: This study serves to expand the clinical phenotypes of atypical USH. Given the variable findings, atypical USH should be considered in patients with peripheral and macular retinal disease even without the typical RP phenotype especially when SNHL is noted. Additionally, genetic screening may be useful in patients that have clinical symptoms and retinal findings even in the absence of known SNHL given the variability of atypical USH.

Pathogenic variants in retinol dehydrogenase 5 (RDH5) attenuate supply of 11-cis-retinal to photoreceptors leading to a range of clinical phenotypes including night blindness because of markedly slowed rod dark adaptation and in some patients, macular atrophy. Current animal models (such as Rdh5−/− mice) fail to recapitulate the functional or degenerative phenotype. Addressing this need for a relevant animal model we present a new domestic cat model with a loss-of-function missense mutation in RDH5 (c.542G > T; p.Gly181Val). As with patients, affected cats have a marked delay in recovery of dark adaptation. In addition, the cats develop a degeneration of the area centralis (equivalent to the human macula). This recapitulates the development of macular atrophy that is reported in a subset of patients with RDH5 mutations and is shown in this paper in seven patients with biallelic RDH5 mutations. There is notable variability in the age at onset of the area centralis changes in the cat, with most developing changes as juveniles but some not showing changes over the first few years of age. There is similar variability in development of macular atrophy in patients and while age is a risk factor, it is hypothesized that genetic modifying loci influence disease severity, and we suspect the same is true in the cat model. This novel cat model provides opportunities to improve molecular understanding of macular atrophy and test therapeutic interventions for RDH5-associated retinopathies.

The full-field electroretinogram (ff-ERG) is a widely used clinical tool to evaluate generalized retinal function by recording electrical potentials generated by the cells in the retina in response to flash stimuli and requires mydriasis. The purpose of this study was to determine the intra-visit reliability and diagnostic capability of a handheld, mydriasis-free ERG, RETeval (LKC Technologies, Gaithersburg, MD, USA), in comparison with the standard clinical ff-ERG by measuring responses recommended by the International Society for Clinical Electrophysiology of Vision (ISCEV).This prospective, cross-sectional study included 35 patients recruited at the Hospital for Sick Children (median age = 17, range 11 months-69 years) who had undergone a clinical ff-ERG according to ISCEV standards. For RETeval (n = 35), pupils were undilated in most (n = 29) and sensor strip electrodes were placed under the inferior orbital rim. Stimulus settings on RETeval were equivalent to those used in the clinical ERG. Fifty-seven control participants (median age = 22, range 8-65 years) underwent undilated RETeval ERG to establish standard values for comparison. Patient waveform components with amplitudes 5th percentile, or implicit times 95th percentile of normal relative to control data were classified as abnormal for the RETeval system.The RETeval system demonstrated a high degree of within-visit reliability for amplitudes (ICC = 0.82) and moderate reliability for implicit times (ICC = 0.53). Cohen's Kappa analysis revealed a substantial level of agreement between the diagnostic capability of RETeval in comparison with clinical ff-ERG (k = 0.82), with a sensitivity and specificity of 1.00 and 0.82, respectively. Pearson's correlations for clinical ERG versus RETeval demonstrated a positive correlation for amplitudes across the rod (r = 0.65) and cone (r = 0.74) ERG waveforms. Bland-Altman plots showed no bias between the mean differences across all amplitude and implicit time parameters of the two systems.The present study demonstrated that RETeval is a reliable tool with reasonable accuracy in comparison with the clinical ERG. The portable nature of RETeval system enables its incorporation at resource-limited centers where the ff-ERG is not readily available. The avoidance of sedation and pupillary dilation are added advantages of RETeval ERG.

Hemizygous pathogenic variants in CACNA1F lead to defective signal transmission from retinal photoreceptors to bipolar cells and cause incomplete congenital stationary night blindness in humans. Although the primary defect is at the terminal end of first-order neurons (photoreceptors), there is limited knowledge of higher-order neuronal changes (inner retinal) in this disorder. This study aimed to investigate inner retinal changes in CACNA1F-retinopathy by analyzing macular ganglion cell layer-inner plexiform layer (GCL-IPL) thickness and optic disc pallor in 22 subjects with molecularly confirmed CACNA1F-retinopathy. Detailed ocular phenotypic data including distance and color vision, refraction and electroretinogram (ERG) were collected. Distance vision was universally reduced (mean: 0.42 LogMAR), six had abnormal color vision and myopia was common (n = 15; mean: −6.32 diopters). Mean GCL-IPL thickness was significantly lower in patients (55.00 µm) compared to age-matched controls (n = 87; 84.57 µm; p << 0.001). The GCL-IPL thickness correlated with scotopic standard (p = 0.04) and bright-flash (p = 0.014) ERG b/a ratios and photopic b-wave amplitudes (p = 0.05). Twenty-one patients had some degree of disc pallor (bilateral in 19). Fifteen putative disease-causing, including five novel variants were identified. This study establishes macular inner retinal thinning and optic atrophy as characteristic features of CACNA1F-retinopathy, which are independent of myopia and could impact potential future treatment strategies.

Leber congenital amaurosis (LCA), a form of autosomal recessive severe early-onset retinal degeneration, is an important cause of childhood blindness. This may be associated with systemic features or not. Here we identified COG5 compound-heterozygous variants in patients affected with a complex LCA phenotype associated with microcephaly and skeletal dysplasia. COG5 is a component of the COG complex, which facilitates retrograde Golgi trafficking; if disrupted this can result in protein misfolding. To date, variants in COG5 have been associated with a distinct congenital disorder of glycosylation (type IIi) and with a variant of Friedreich’s ataxia. We show that COG5 variants can also result in fragmentation of the Golgi apparatus and upregulation of the UPR modulator, PKR-like endoplasmic reticulum kinase (PERK). In addition, upregulation of PERK induces DNA damage in cultured cells and in murine retina. This study identifies a novel role for COG5 in maintaining ER protein homeostasis and that disruption of that role results in activation of PERK and early-onset retinal degeneration, microcephaly and skeletal dysplasia. These results also highlight the importance of the UPR pathway in early-onset retinal dystrophy and as potential therapeutic targets for patients.

Objective: Although vigabatrin (VGB) is effective and well tolerated for the treatment of epileptic spasms, there are safety concerns. The aim of this systematic review and metaanalysis was to assess adverse events of VGB for the treatment of epileptic spasms. Methods: MEDLINE, EMBASE, and Cochrane databases were searched. The population was infants treated with VGB for epileptic spasms. The outcomes were VGB-related adverse events. Meta-analyses of VGB-related MRI abnormalities, retinal toxicity as measured by electroretinogram (ERG), visual field defect as measured by perimetry, and other adverse events were conducted. Results: Fifty-seven articles were included in the systematic review. The rate of VGB-related MRI abnormalities was 21% (95% CI: 15–29%). Risk factors for MRI abnormalities were age younger than 12 months and higher VGB dose. VGB-related retinal toxicity and visual field defect occurred in 29% (95% CI: 7–69%) and 28% (95% CI: 4–78%) respectively. Other adverse events occurred in 23% (95% CI: 16–34%), consisting predominantly of central nervous system symptoms, and the majority of these did not require therapeutic modification. Conclusion: This study will inform physicians and families on the risk profile of VGB for the treatment of epileptic spasms and will help decisions on treatment options.

To determine the prevalence of choroidal abnormalities (CAs) and Lisch nodules (LNs) in children who met the clinical diagnostic criteria (CDC) alone and those with a molecularly confirmed diagnosis (MCD) of neurofibromatosis type 1 (NF1), and to ascertain any differences between the groups.This was a cross-sectional observational study. All children who met the CDC and/or had MCD of NF1 and underwent eye examination were included. At least two CAs or LNs between the two eyes were set as a threshold to define the presence of either abnormality. Frequencies alongside 95% confidence intervals (CIs) were calculated. The relationship between patient age and the presence of LNs and/or CAs was estimated using logistic regression.The study cohort included 94 patients; CAs (64%) were more prevalent than LNs (41%) (0.22; 95% CI, 0.08-0.36; P = 0.0023). The probability of the presence of LNs was lower than that of CAs across all ages (odds ratio = 0.37; 95% CI, 0.20-0.69; P = 0.00173). CAs were exclusively found in 37% of patients and LNs in 16%; 80% had either CAs or LNs, or both. In the CDC group (n = 41), the difference in prevalence (CAs = 68%, LNs = 51%) did not attain statistical significance (0.17; 95% CI, -0.06 to 0.40; P = 0.18). In the MCD group (n = 53), the difference in prevalence (CAs = 60%, LNs = 34%) was significant (0.26; 95% CI, 0.006-0.47; P = 0.023).CAs were more frequent than LNs in pediatric NF1 patients regardless of age and MCD status. Combining ophthalmological exams with near-infrared imaging will increase the diagnostic reach in pediatric NF1.CAs detected on near-infrared imaging are objective biomarkers in NF1. They are more prevalent and detected earlier in the pediatric population compared with LNs. Hence, the presence of CAs should be routinely ascertained in children suspected with NF1.

Axenfeld-Rieger syndrome is characterized by a spectrum of anterior segment dysgenesis involving neural-crest-derived tissues, most commonly secondary to mutations in the transcription factor genesSingle retrospective case report.A full-term infant presented at 5 weeks of age with bilateral Peters anomaly and Axenfeld-Rieger syndrome, with development of atypical features of progressive corneal neovascularization and proliferative vitreoretinopathy. Despite surgical interventions, the patient progressed to bilateral phthisis bulbi by 22 months of age. Genetic testing revealed a novel de novo p.Leu212Valfs*39 mutation inIt is important to consider mutations in

S-adenosylhomocysteine hydrolase deficiency due to pathologic variants in AHCY gene is a rare neurometabolic disease for which no eye phenotype has been documented. Pathologic variants in CRB1 gene are known to cause a wide spectrum of autosomal recessive retinal diseases with Leber’s congenital amaurosis as a most common. The aim of this study is to report co-inheritance of neurometabolic disease and eye disease in a pedigree. Comprehensive eye examination was performed in available family members together with color vision test, visual fields, fundus images, OCT, electroretinogram and visual evoked potentials. Genetic testing included whole-exome sequencing (WES), retinal dystrophy gene panel and segregation analysis. Two children from a family not known to be consanguineous were affected with neurometabolic disease and one of them presented with reduced vision due to maculopathy. The mother had symptoms of retinal degeneration of unspecified cause. Clinical WES revealed homozygous missense pathologic variants in AHCY gene c.148G>A, p.(Ala50Thr) as a cause of S-adenosylhomocysteine hydrolase deficiency. Retinal dystrophy gene panel sequencing revealed two heterozygous missense pathologic variants in CRB1 gene c.1831T>C, p.(Ser611Pro) and c.3955T>C, p.(Phe1319Leu) in the proband and her mother. These variants segregated with disease phenotype in family members. Establishing an ocular genetic diagnosis may be challenging with the co-existence of a rare systemic genetic disease with previously unknown eye involvement. Extensive phenotyping and genotyping of available family members showed that the proband and her mother shared a CRB1-related retinopathy at different stages while the brother did not.

International audience; Purpose: To demonstrate the effectiveness of combining retinal phenotyping and focused variant filtering from genome sequencing (GS) in identifying deep intronic disease causing variants in inherited retinal dystrophies.Methods: Affected members from three pedigrees with classical enhanced S-cone syndrome (ESCS; Pedigree 1), congenital stationary night blindness (CSNB; Pedigree 2), and achromatopsia (ACHM; Pedigree 3), respectively, underwent detailed ophthalmologic evaluation, optical coherence tomography, and electroretinography. The probands underwent panel-based genetic testing followed by GS analysis. Minigene constructs (NR2E3, GPR179 and CNGB3) and patient-derived cDNA experiments (NR2E3 and GPR179) were performed to assess the functional effect of the deep intronic variants.Results: The electrophysiological findings confirmed the clinical diagnosis of ESCS, CSNB, and ACHM in the respective pedigrees. Panel-based testing revealed heterozygous pathogenic variants in NR2E3 (NM_014249.3; c.119-2A>C; Pedigree 1) and CNGB3 (NM_019098.4; c.1148delC/p.Thr383Ilefs*13; Pedigree 3). The GS revealed heterozygous deep intronic variants in Pedigrees 1 (NR2E3; c.1100+1124G>A) and 3 (CNGB3; c.852+4751A>T), and a homozygous GPR179 variant in Pedigree 2 (NM_001004334.3; c.903+343G>A). The identified variants segregated with the phenotype in all pedigrees. All deep intronic variants were predicted to generate a splice acceptor gain causing aberrant exonization in NR2E3 [89 base pairs (bp)], GPR179 (197 bp), and CNGB3 (73 bp); splicing defects were validated through patient-derived cDNA experiments and/or minigene constructs and rescued by antisense oligonucleotide treatment.Conclusions: Deep intronic mutations contribute to missing heritability in retinal dystrophies. Combining results from phenotype-directed gene panel testing, GS, and in silico splice prediction tools can help identify these difficult-to-detect pathogenic deep intronic variants.

Ciliopathies, a growing pleotropic class of diseases due to mutations in genes that play an important role in primary cilia function. These highly conserved organelles are key to cell signaling. We now know, that mutations in one gene may lead to more than one ciliopathy phenotype and that one ciliopathy phenotype may be due to mutations in more than one gene. We studied the case of a female child with a novel ciliopathy phenotype and identified two novel mutations in the gene IFT80. Previously, mutations in IFT80 have been associated with a very narrow rib cage and failure of the lungs. Bone anomalies are also part of this IFT80-condition but with no vision problems documented. Our case had none of the features known to be associated with IFT80 mutations and had retinal degeneration (RD). This work broadens the IFT80-phenotype spectrum and also shows RD can be a feature of many ciliopathies.

Background ERCC6L2‐associated disorder has recently been described and only five patients were reported so far. The described phenotype included bone marrow, cerebral, and craniofacial abnormalities. The aim of this study was to further define the genetic and phenotypic spectrum of the disorder by summarizing the five published cases and an additional case that we identified through whole‐exome sequencing performed at the University of Toronto. Methods Clinical data was extracted from the Canadian Inherited Marrow Failure Registry. Whole exome sequencing was performed to identify causative mutations. Results All six cases had homozygous truncating mutations either at or upstream of the helicase domain of ERCC6L2. All patients displayed bone marrow failure, learning or developmental delay and microcephaly. Our patient was unique in displaying features of cerebellar disease, including ataxia and dysmetria as well as an interval deterioration of the corpus callosum and generalized volume loss on MRI. Another unique feature of our patient was retinal dystrophy with macular involvement. Along with one other patient, our patient displayed craniofacial abnormalities by presenting with low‐set prominent ears, a pointed prominent chin, and deep‐set eyes. Leukemia is common among patients with inherited bone marrow failure, but thus far, none of the patients have developed this complication. Conclusions ERCC6L2‐associated disorder is a multisystem disorder. The phenotype spectrum includes bone marrow failure, cerebral, and craniofacial abnormalities, as well as cerebellar and retinal abnormalities.

Purpose Genetic testing is an integral diagnostic component of pediatric medicine. Standard of care is often a time-consuming stepwise approach involving chromosomal microarray analysis and targeted gene sequencing panels, which can be costly and inconclusive. Whole-genome sequencing (WGS) provides a comprehensive testing platform that has the potential to streamline genetic assessments, but there are limited comparative data to guide its clinical use. Methods We prospectively recruited 103 patients from pediatric non-genetic subspecialty clinics, each with a clinical phenotype suggestive of an underlying genetic disorder, and compared the diagnostic yield and coverage of WGS with those of conventional genetic testing. Results WGS identified diagnostic variants in 41% of individuals, representing a significant increase over conventional testing results (24% P = 0.01). Genes clinically sequenced in the cohort (n = 1,226) were well covered by WGS, with a median exonic coverage of 40 × ±8 × (mean ±SD). All the molecular diagnoses made by conventional methods were captured by WGS. The 18 new diagnoses made with WGS included structural and non-exonic sequence variants not detectable with whole-exome sequencing, and confirmed recent disease associations with the genes PIGG, RNU4ATAC, TRIO, and UNC13A. Conclusion WGS as a primary clinical test provided a higher diagnostic yield than conventional genetic testing in a clinically heterogeneous cohort.

PURPOSE: To describe the ocular and systemic phenotype in IQCB1-related disease. METHODS: Four cases (3 males, 1 female) with molecularly confirmed IQCB1-related disease underwent ophthalmological examination including best-corrected visual acuity (BCVA) measurement, fundus evaluation, electroretinography (ERG), and spectral-domain optical coherence tomography (SD-OCT). Systemic evaluation including abdominal ultrasound was performed in all cases. RESULTS: BCVA ranged from perception of light (Case-2; 1 year) to 20/125 (Case-1; 9 years). Fundus evaluation showed whitish or silvery reflex outside the vascular arcades in all cases; the reflex was circumferential, irregular and covered at-least 6 clock hours at younger ages (3 cases; 1–4 years). The reflex was less conspicuous with increasing age (Case-1 (9 years) and Case-4 (20 years)). The peripheral retinal SD-OCT scans showed evidence of extensive deposition at the level of retinal pigment epithelium with complete absence of overlying photoreceptor outer segments and myoid zone. The ERG was non-detectable in all cases. All cases harbored biallelic nonsense (p.R364*, p. R455*) or frameshifting (p.M370Yfs*49, p.C253Afs*9) mutations in IQCB1. Case-1 additionally had developmental delay, hemi-hyperplasia, toe syndactyly, and kidney cysts. CONCLUSION: IQCB1-related syndromic or non-syndromic Leber congenital amaurosis (LCA) carries unique retinal characteristics which helps differentiate IQCB1-retinopathy from other genetic forms of LCA in childhood.

Lafora disease (LD) is a teenage-onset progressive neurologic disorder caused by biallelic mutations in EPM2A (laforin) or EPM2B (malin) encoding laforin phosphatase and malin ubiquitin E3 ligase, respectively, both involved in glycogen structural integrity. Defective laforin or malin results in neuronal accumulation of malformed insoluble glycogen termed Lafora bodies (LBs).1 Histologic reports indicate LB accumulation in the inner retinal layers with evidence of bipolar cell atrophy.2 Funduscopic retinal examination has been reported unremarkable except in one patient with unilateral optic atrophy that may have been unrelated to LD.3,4 Recently, retinitis pigmentosa was reported in a 21-year-old patient diagnosed only on skin biopsy, and was highlighted on the journal cover.5 A subsequent letter to the editor suggested that this may represent an instance of false-positive interpretation of skin biopsy, but the debate remains unsettled.1,5,6 We aimed to address this issue by performing multimodal imaging and electrophysiology (e-Methods in [links.lww.com/WNL/A580][1]) to characterize the eye phenotype in 4 patients with genetically confirmed LD, concurrently setting the stage to identify potentially useful ophthalmologic biomarkers in LD. [1]: http://links.lww.com/WNL/A580

To report a unique retinal signaling defect in GNB5-related disease. A 3-year-old female child underwent detailed systemic and ophthalmological evaluation. The eye examination included fundus photography, spectral domain optical coherence tomography and an extended protocol full-field electroretinography (ERG) including the ISCEV recommended standard steps. The dark-adapted (DA) ERGs were performed to a series of white flashes (range 0.006–30.0 cd s m−2) and two red flashes. The DA ERGs to higher stimulus intensities (3.0, 10.0 and 30.0 cd s m−2) were tested using a range of inter-stimulus intervals (ISI) of up to 60 s. In addition to standard light-adapted (LA) ERGs, a short-duration (0.5 s) LA 3.0 30-Hz flicker ERG and a long-duration LA ON–OFF ERG were also performed. Genetic testing included microarray, mitochondrial genome testing and whole exome sequencing. The child was diagnosed to have status epilepticus and bradycardia at 6 months of age. Subsequently, she was diagnosed to have global developmental delay and hypotonia. On ophthalmological evaluation, the child fixes and follows light. Fundus evaluation showed mild optic disk pallor; macular SD-OCT was normal. The dim flash DA ERGs (DA 0.006 and DA 0.01 cd s m−2) were non-detectable. DA red flash ERGs showed the presence of an x-wave (cone component) and no rod component. The DA 3.0, 10.0 and 30.0 ERGs showed electronegative configuration regardless of the ISI; the averaged a-wave amplitude (4 flashes) was smaller at shorter ISI but became normal at a prolonged ISI (60 s). The LA 30-Hz flicker ERG was severely reduced but detectable for the initial 0.5 s; this became non-detectable after 5 s of averaging. The LA 3.0 2-Hz ERG showed markedly reduced a- and b-wave amplitudes and a reduced b:a ratio; the LA ON–OFF ERGs were non-detectable. WES identified a homozygous null mutation in G protein subunit beta 5 (GNB5; c.1032C>A/p.Tyr344*). This report identifies for the first time a unique retinopathy associated with biallelic mutations in GNB5. The observed phenotype is consistent with a dual retinal signaling defect reminiscent of features of bradyopsia and rod ON-bipolar dysfunction.

FLVCR1 encodes for a transmembrane heme exporter protein and it is known to cause a rare form of syndromic retinitis pigmentosa: posterior column ataxia with retinitis pigmentosa. Recently, the FLVCR1-associated phenotype has been expanded with sporadic reports of hereditary sensory-autonomic neuropathy or non-syndromic retinitis pigmentosa. Here, we report a 23-year- old female with early onset hypomyelinating sensory-autonomic neuropathy and retinitis pigmentosa. Both features were present since childhood. The patient developed signs of advanced retinitis pigmentosa by the age of 10 years leading to legal blindness after the age of 18. Following candidate gene panel testing, which was negative, whole exome sequencing revealed compound heterozygous pathogenic FLVCR1 variants: NM_014053.3: c.3G > T; p.(Met1?) and NM_014053.3: c.730G > A; p.(Gly244Ser), the latter variant is novel. In this report we highlight the association of retinitis pigmentosa with hypomyelinating sensory-autonomic neuropathy, which could be underdiagnosed due to variable severity. To summarize, the phenotypic heterogeneity of FLVCR1 variants is broad and should include retinitis pigmentosa along with range of neurological features.

Author(s): Birch, David G; Cheng, Peiyao; Duncan, Jacque L; Ayala, Allison R; Maguire, Maureen G; Audo, Isabelle; Cheetham, Janet K; Durham, Todd A; Fahim, Abigail T; Ferris, Frederick L; Heon, Elise; Huckfeldt, Rachel M; Iannaccone, Alessandro; Khan, Naheed W; Lad, Eleonora M; Michaelides, Michel; Pennesi, Mark E; Stingl, Katarina; Vincent, Ajoy; Weng, Christina Y; Foundation Fighting Blindness Consortium Investigator Group | Abstract: PurposeThe purpose of this study was to evaluate baseline best corrected visual acuity (BCVA), full-field electroretinography (ERG), full-field stimulus thresholds (FST), and their relationship with baseline demographic and clinical characteristics in the Rate of Progression in Usher syndrome type 2 (USH2A)-related Retinal Degeneration (RUSH2A) multicenter study.MethodsParticipants had Usher syndrome type 2 (USH2, N = 80) or autosomal recessive nonsyndromic retinitis pigmentosa (ARRP, Nn=n47) associated with biallelic variants in the USH2A gene. Associations of demographic and clinical characteristics with BCVA, ERG, and FST were assessed with regression models.ResultsIn comparison to ARRP, USH2 had worse BCVA (median 79 vs. 82 letters; P l 0.001 adjusted for age), lower rod-mediated ERG b-wave amplitudes (median 0.0 vs. 6.6nµV; P l 0.001) and 30 Hz flicker cone-mediated ERG amplitudes (median 1.5 vs. 3.1 µV; Pn=n0.001), and higher (white, blue, and red) FST thresholds (means [-26, -31, -23ndB] vs. [-39, -45, -28ndB]; P l 0.001 for all stimuli). After adjusting for age, gender, and duration of vision loss, the difference in BCVA between diagnosis groups was attenuated (Pn=n0.09). Only diagnosis was associated with rod- and cone-mediated ERG parameters, whereas both genders (Pn=n0.04) and duration of visual loss (P l 0.001) also were associated with FST white stimulus.ConclusionsUSH2 participants had worse BCVA, ERG, and FST than ARRP participants. FST was strongly associated with duration of disease; it remains to be determined whether it will be a sensitive measure of progression.Translational relevanceUsing standardized research protocols in RUSH2A, measures have been identified to monitor disease progression and treatment response and differentiate features of prognostic relevance between USH2 and ARRP participants with USH2A mutations.

Contains fulltext : 168325.pdf (Publisher’s version ) (Open Access) PURPOSE: To identify the genetic cause of autosomal recessive familial foveal retinoschisis (FFR). METHODS: A female sibship with FFR was identified (Family-A; 17 and 16 years, respectively); panel based genetic sequencing (132 genes) and comparative genome hybridization (142 genes) were performed. Whole-exome sequencing (WES) was performed on both siblings using the Illumina-HiSeq-2500 platform. A sporadic male (Family-B; 35 years) with FFR underwent WES using Illumina NextSeq500. All three affected subjects underwent detailed ophthalmologic evaluation including fundus photography, autofluorescence imaging, spectral-domain optical coherence tomography (SD-OCT), and full-field electroretinogram (ERG). RESULTS: Panel-based genetic testing identified two presumed disease causing variants in CRB1 (p.Gly123Cys and p.Cys948Tyr) in Family-A sibship; no deletion or duplication was detected. WES analysis in the sibship identified nine genes with two or more shared nonsynonymous rare coding sequence variants; CRB1 remained a strong candidate gene, and CRB1 variants segregated with the disease. WES in Family-B identified two presumed disease causing variants in CRB1 (p.Ile167_Gly169del and p.Arg764Cys) that segregated with the disease phenotype. Distance visual acuity was 20/40 or better in all three affected except for the left eye of the older subject (Family-B), which showed macular atrophy. Fundus evaluation showed spoke-wheel appearance at the macula in five eyes. The SD-OCT showed macular schitic changes in inner and outer nuclear layers in all cases. The ERG responses were normal in all subjects. CONCLUSIONS: This is the first report to implicate CRB1 as the underlying cause of FFR. This phenotype forms the mildest end of the spectrum of CRB1-related diseases.

Background Autoimmune polyglandular syndrome type 1 (APS1) is a rare autosomal recessive disorder due to mutations in the AIRE gene. Aim To report the ocular features and characterise the retinal phenotype in molecularly confirmed APS1. Method This retrospective case series reviewed five molecularly confirmed cases with APS1 known to have ocular involvement (age range: 19 months–44 years; mean follow-up of 8 years). The medical history, ocular history and evaluation, visual field testing, full-field electroretinogram (ERG) and antiretinal antibody results were reviewed. Results All but one case had decreased vision at first presentation. All cases had peripheral pigmentary retinal changes; macular atrophy was noted in 80% of cases. The most common feature on spectral-domain optical coherence tomography was a disruption of the external limiting membrane and inner segment ellipsoid band (n=3). Fundus autofluorescence imaging demonstrated a parafoveal ring of hyper-autofluorescence (n=1) or a stippled and patchy autofluorescence pattern in the macula (n=1). The visual fields were constricted in all tested patients (n=3). The rod ERG was abnormal in all cases; the relative involvement of rods and cones differed. Four patients who were tested for antiretinal antibodies were found positive by immunohistochemistry (n=3) and/or western blot (n=2). Conclusions Photoreceptor degeneration is part of APS1 phenotype and the presence of antiretinal antibodies strongly supports an aetiology similar to that of non-paraneoplastic autoimmune retinopathy. Periodic retinal evaluation and imaging, visual field testing and ERG would assist in monitoring the retinopathy in APS1-related disease.

Purpose: To define the phenotype of C2orf71 associated retinopathy and to present novel mutations in this gene. Methods: A retrospective multicenter study of patients with retinopathy and identified C2orf71 mutations was performed. Ocular function (visual acuity, visual fields, electroretinogram [ERG] responses); retinal morphology (fundus, optical coherence tomography); and underlying mutations were analyzed. Results: Thirteen patients from 11 families, who were aged 7 to 63 years (mean: 32.1 years) at their first examination with presumed compound heterozygous (6/13 patients) or homozygous (7/13 patients) C2orf71 mutations were identified. Eight of the mutations were novel. Truncation mutations were responsible in all cases. Nyctalopia was observed in less than 50% of patients. Visual acuity ranged from 20/20 to light perception. Severe visual loss was associated with atrophic maculopathy. Full-field ERG responses showed severe progressive cone-rod or rod-cone dysfunction. Typical fundus changes were progressive symmetrical retinopathy with an early mild maculopathy and patchy circular midperipheral RPE atrophy. Normal retinal lamination was preserved despite early disruption of the ellipsoid zone and RPE irregularities. Outer retinal tubulations were associated with better-preserved visual acuity. Conclusions: On the basis of our multicenter analysis, C2orf71 might represent a more frequently mutated gene in autosomal recessive retinitis pigmentosa in some populations. The phenotype analysis over a wide age range showed a variable and progressive retinal degeneration with early onset maculopathy and a better visual potential before the age of 30 years., Investigative Ophthalmology & Visual Science, 58 (10), ISSN:0146-0404

Roifman syndrome (OMIM# 616651) is a complex syndrome encompassing skeletal dysplasia, immunodeficiency, retinal dystrophy and developmental delay, and is caused by compound heterozygous mutations involving the Stem II region and one of the other domains of the RNU4ATAC gene. This small nuclear RNA gene is essential for minor intron splicing. The Canadian Centre for Primary Immunodeficiency Registry and Repository were used to derive patient information as well as tissues. Utilising RNA sequencing methodologies, we analysed samples from patients with Roifman syndrome and assessed intron retention. We demonstrate that a homozygous mutation in Stem II is sufficient to cause the full spectrum of features associated with typical Roifman syndrome. Further, we demonstrate the same pattern of aberration in minor intron retention as found in cases with compound heterozygous mutations.

Importance:Mutations in genes traditionally associated with syndromic retinal disease are increasingly found to cause nonsyndromic inherited retinal degenerations. Mutations in CLN3 are classically associated with juvenile neuronal ceroid lipofuscinosis, a rare neurodegenerative disease with early retinal degeneration and progressive neurologic deterioration, but have recently also been identified in patients with nonsyndromic inherited retinal degenerations. To our knowledge, detailed clinical characterization of such cases has yet to be reported. Objective:To provide detailed clinical, electrophysiologic, structural, and molecular genetic findings in nonsyndromic inherited retinal degenerations associated with CLN3 mutations. Design, Setting, and Participants:A multi-institutional case series of 10 patients who presented with isolated nonsyndromic retinal disease and mutations in CLN3. Patient ages ranged from 16 to 70 years; duration of follow-up ranged from 3 to 29 years. Main Outcomes and Measures:Longitudinal clinical evaluation, including full ophthalmic examination, multimodal retinal imaging, perimetry, and electrophysiology. Molecular analyses were performed using whole-genome sequencing or whole-exome sequencing. Electron microscopy studies of peripheral lymphocytes and CLN3 transcript analysis with polymerase chain reaction amplification were performed in a subset of patients. Results:There were 7 females and 3 males in this case series, with a mean (range) age at last review of 37.1 (16-70) years. Of the 10 patients, 4 had a progressive late-onset rod-cone dystrophy, with a mean (range) age at onset of 29.7 (20-40) years, and 6 had an earlier onset rod-cone dystrophy, with a mean (range) age at onset of 12.1 (7-17) years. Ophthalmoscopic examination features included macular edema, mild intraretinal pigment migration, and widespread atrophy in advanced disease. Optical coherence tomography imaging demonstrated significant photoreceptor loss except in patients with late-onset disease who had a focal preservation of the ellipsoid zone and outer nuclear layer in the fovea. Electroretinography revealed a rod-cone pattern of dysfunction in 6 patients and were completely undetectable in 2 patients. Six novel CLN3 variants were identified in molecular analyses. Conclusions and Relevance:This report describes detailed clinical, imaging, and genetic features of CLN3-associated nonsyndromic retinal degeneration. The age at onset and natural progression of retinal disease differs greatly between syndromic and nonsyndromic CLN3 disease, which may be associated with genotypic differences.

There is an Inside Blood Commentary on this article in this issue.

Achromatopsia is an autosomal recessive disorder characterized by cone photoreceptor dysfunction. We recently identified activating transcription factor 6 (ATF6) as a genetic cause of achromatopsia. ATF6 is a key regulator of the unfolded protein response. In response to endoplasmic reticulum (ER) stress, ATF6 migrates from the ER to Golgi to undergo regulated intramembrane proteolysis to release a cytosolic domain containing a basic leucine zipper (bZIP) transcriptional activator. The cleaved ATF6 fragment migrates to the nucleus to transcriptionally up-regulate protein-folding enzymes and chaperones. ATF6 mutations in patients with achromatopsia include missense, nonsense, splice site, and single-nucleotide deletion or duplication changes found across the entire gene. Here, we comprehensively tested the function of achromatopsia-associated ATF6 mutations and found that they group into three distinct molecular pathomechanisms: class 1 ATF6 mutants show impaired ER-to-Golgi trafficking and diminished regulated intramembrane proteolysis and transcriptional activity; class 2 ATF6 mutants bear the entire ATF6 cytosolic domain with fully intact transcriptional activity and constitutive induction of downstream target genes, even in the absence of ER stress; and class 3 ATF6 mutants have complete loss of transcriptional activity because of absent or defective bZIP domains. Primary fibroblasts from patients with class 1 or class 3 ATF6 mutations show increased cell death in response to ER stress. Our findings reveal that human ATF6 mutations interrupt distinct sequential steps of the ATF6 activation mechanism. We suggest that increased susceptibility to ER stress-induced damage during retinal development underlies the pathology of achromatopsia in patients with ATF6 mutations.