Clinical and genetic characterization of RDH12-retinal dystrophy in a South American cohort

Purpose: To characterize the largest cohort of individuals with RDH12-retinal dystrophy to date, and the first one from South America. // Design: Retrospective multicenter international study. // Subjects: 78 patients (66 families) with an inherited retinal dystrophy and biallelic variants in RDH12. // Methods: Review of clinical notes, ophthalmic images, and molecular diagnosis. // Main outcome measures: Visual function, retinal imaging and characteristics were evaluated and correlated. // Results: Thirty-seven individuals self-identified as Latino (51%) and 34 as White (47%). Mean age at the baseline visit was 19.8 ± 13 years old (6 months – 46 years old, median 18.5); 41 (53%) were children. Thirty-nine patients (50%) had subsequent visits, with mean follow-up of 6.8 + 7.3 years (0 – 29). Sixty-nine individuals (88%) had Leber congenital amaurosis/early onset severe retinal dystrophy (LCA/EOSRD). Macular and mid-peripheral atrophy was seen in all patients from 3 years of age. A novel retinal finding was a hyperautofluorescent ring in 2 young children with LCA. Eight variants (21%) were previously unreported and the most frequent variant was c.295C>A, p.Leu99Ile, present in 52 alleles of 32 probands. Individuals with LCA homozygous for p.Leu99Ile (31%) had a later age of onset, slower rate of BCVA decrease, the largest percentage of patients with mild visual impairment, and were predicted to reach legal blindness at an older age than the rest of the cohort. // Conclusions: By describing the largest molecularly confirmed cohort to date, improved understanding of disease progression was possible. Our detailed characterization aims to support research and the development of novel therapies that may have the potential to reduce or prevent vision loss in individuals with RDH12-associated retinal dystrophy

Nationwide genetic analysis of more than 600 families with inherited eye diseases in Argentina

This study corresponds to the first large-scale genetic analysis of inherited eye diseases (IED) in Argentina and describes the comprehensive genetic profile of a large cohort of patients. Medical records of 22 ophthalmology and genetics services throughout 13 Argentinian provinces were analyzed retrospectively. Patients with a clinical diagnosis of an ophthalmic genetic disease and a history of genetic testing were included. Medical, ophthalmological and family history was collected. A total of 773 patients from 637 families were included, with 98% having inherited retinal disease. The most common phenotype was retinitis pigmentosa (RP, 62%). Causative variants were detected in 379 (59%) patients. USH2A, RPGR, and ABCA4 were the most common disease-associated genes. USH2A was the most frequent gene associated with RP, RDH12 early-onset severe retinal dystrophy, ABCA4 Stargardt disease, PROM1 cone-rod dystrophy, and BEST1 macular dystrophy. The most frequent variants were RPGR c.1345 C > T, p.(Arg449*) and USH2A c.15089 C > A, p.(Ser5030*). The study revealed 156/448 (35%) previously unreported pathogenic/likely pathogenic variants and 8 possible founder mutations. We present the genetic landscape of IED in Argentina and the largest cohort in South America. This data will serve as a reference for future genetic studies, aid diagnosis, inform counseling, and assist in addressing the largely unmet need for clinical trials to be conducted in the region