Novel deletion and nonsense pathogenic variant in Bardet-Biedl syndrome.

Background: Bardet-Biedl syndrome (BBS) is a rare syndromic ciliopathy characterized with retinal degeneration and a broad range of systemic features. Twenty-six BBS-associated genes have been identified to date and clinical genetic testing resolves around 80% of the cases. Two BBS cases unsolved by clinical genetic testing were recruited to identify causative variants using next-generation sequencing.

Autosomal-dominant macular dystrophy linked to a chromosome 17 tandem duplication.

Hereditary macular dystrophies (HMDs) are a genetically diverse group of disorders that cause central vision loss due to photoreceptor and retinal pigment epithelium (RPE) damage. We investigated a family with a presumed novel autosomal-dominant HMD characterized by faint, hypopigmented RPE changes involving the central retina. Genome and RNA sequencing identified the disease-causing variant to be a 560 kb tandem duplication on chromosome 17 [NC_000017.

Retinal Dystrophies Associated With Peripherin-2: Genetic Spectrum and Novel Clinical Observations in 241 Patients.

Purpose: To describe the clinical, electrophysiological and genetic spectrum of inherited retinal diseases associated with variants in the PRPH2 gene.

Methods: A total of 241 patients from 168 families across 15 sites in 9 countries with pathogenic or likely pathogenic variants in PRPH2 were included. Records were reviewed for age at symptom onset, visual acuity, full-field ERG, fundus colour photography, fundus autofluorescence (FAF), and SD-OCT.

Scaling up Functional Analyses of the G Protein-Coupled Receptor Rhodopsin.

Eukaryotic cells use G protein-coupled receptors (GPCRs) to convert external stimuli into internal signals to elicit cellular responses. However, how mutations in GPCR-coding genes affect GPCR activation and downstream signaling pathways remain poorly understood. Approaches such as deep mutational scanning show promise in investigations of GPCRs, but a high-throughput method to measure rhodopsin activation has yet to be achieved.

Functional Vision in Patients With Biallelic USH2A Variants.

Purpose: To describe functional vision (FV) and investigate the relationship between FV, visual acuity (VA), and hill of vision (V) at baseline in patients with biallelic USH2A variants.

Design: Multicenter, international, cross-sectional study.

Methods: In individuals with biallelic disease-causing variants in USH2A, clinical diagnosis of Usher syndrome type 2 (USH2) or autosomal recessive nonsyndromic retinitis pigmentosa (ARRP) was based on history of hearing loss and audiology examinations.

Deep phenotypic characterization of the retinal dystrophy in patients with RNU4ATAC-associated Roifman syndrome.

Purpose: To characterize the retinal phenotype in RNU4ATAC-associated Roifman syndrome.

Methods: Ten patients (including 8 males) with molecularly confirmed Roifman syndrome underwent detailed ophthalmologic evaluation including fundus imaging, fundus autofluorescence (FAF) imaging, spectral-domain optical coherence tomography (SD-OCT), and electroretinography (ERG). Six patients had follow-up eye exams.

The validation of inherited retinal disease-specific patient-reported outcome measures in adolescent patients.

Purpose: 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).

Methods: 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).

Whole genome sequencing for -associated disease reveals several pathogenic deep-intronic variants that are amenable to splice correction.

A significant number of individuals with a rare disorder such as Usher syndrome (USH) and (non-)syndromic autosomal recessive retinitis pigmentosa (arRP) remain genetically unexplained. Therefore, we assessed subjects suspected of -associated disease and no or mono-allelic variants using whole genome sequencing (WGS) followed by an improved pipeline for variant interpretation to provide a conclusive diagnosis. One hundred subjects were screened using WGS to identify causative variants in or other USH/arRP-associated genes.

Shedding light on myopia by studying complete congenital stationary night blindness.

Myopia is the most common eye disorder, caused by heterogeneous genetic and environmental factors. Rare progressive and stationary inherited retinal disorders are often associated with high myopia. Genes implicated in myopia encode proteins involved in a variety of biological processes including eye morphogenesis, extracellular matrix organization, visual perception, circadian rhythms, and retinal signaling.

Photoreceptor Function and Structure in Autosomal Dominant Vitelliform Macular Dystrophy Caused by BEST1 Mutations.

Purpose: The purpose of this study was to evaluate rod and cone function and outer retinal structure within macular lesions, and surrounding extralesional areas of patients with autosomal dominant Best vitelliform macular dystrophy caused by BEST1 mutations.

Methods: Seventeen patients from seven families were examined with dark- and light-adapted chromatic perimetry and optical coherence tomography. Subsets of patients had long-term follow-up (14-22 years, n = 6) and dark-adaptation kinetics measured (n = 5).

Photoreceptor function and structure in retinal degenerations caused by biallelic BEST1 mutations.

The only approved retinal gene therapy is for biallelic RPE65 mutations which cause a recessive retinopathy with a primary molecular defect located at the retinal pigment epithelium (RPE). For a distinct recessive RPE disease caused by biallelic BEST1 mutations, a pre-clinical proof-of-concept for gene therapy has been demonstrated in canine eyes. The current study was undertaken to consider potential outcome measures for a BEST1 clinical trial in patients demonstrating a classic autosomal recessive bestrophinopathy (ARB) phenotype.

Baseline Microperimetry and OCT in the RUSH2A Study: Structure-Function Association and Correlation With Disease Severity.

Purpose: 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.

Design: 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.

Deep intronic variant in MVK as a cause for mevalonic aciduria initially presenting as non-syndromic retinitis pigmentosa.

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.

Unilateral cataract and congenital stationary night blindness in a child with novel variants in TRPM1.

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.

Novel Exon 3 Haplotype-Associated Splicing Defect in Patients with X-Linked Cone Dysfunction.

Certain combinations of common variants in exon 3 of and , 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.

The State of Patient-Reported Outcome Measures for Pediatric Patients with Inherited Retinal Disease.

Patient-reported outcome measures (PROMs) are questionnaires that assess health outcomes meaningful to the patient. PROMs have multiple applications, such as supporting clinicians' decision-making for patient care, understanding the impact of disease on patient functioning, and evaluating the efficacy of therapeutics. Though PROMs were developed for various eye conditions, no PROM was tailored to pediatric patients with inherited retinal disease (IRD).

Tissue-specific genotype-phenotype correlations among USH2A-related disorders in the RUSH2A study.

We assessed genotype-phenotype correlations among the visual, auditory, and olfactory phenotypes of 127 participants with Usher syndrome (USH2) (n =80) or nonsyndromic autosomal recessive retinitis pigmentosa (ARRP) (n = 47) due to USH2A variants, using clinical data and molecular diagnostics from the Rate of Progression in USH2A Related Retinal Degeneration (RUSH2A) study. USH2A truncating alleles were associated with USH2 and had a dose-dependent effect on hearing loss severity with no effect on visual loss severity within the USH2 subgroup. A group of missense alleles in an interfibronectin domain appeared to be hypomorphic in ARRP.

Prevalence of Choroidal Abnormalities and Lisch Nodules in Children Meeting Clinical and Molecular Diagnosis of Neurofibromatosis Type 1.

Purpose: 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.

Methods: 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.

Comparative Natural History of Visual Function From Patients With Biallelic Variants in BBS1 and BBS10.

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.