Genetic landscape of inherited retinal dystrophies in a Welsh Tertiary Referral Centre

Abstract

Aims/Purpose: Inherited retinal dystrophies (IRD) are a group of predominantly monogenic disorders which have genetically heterogeneous origins and display wide clinical phenotypic heterogeneity. The current study aims to describe the clinical diagnoses, demographics, and genetic aetiology of patients in an adult cohort of Welsh patients to provide insight into the rates of genetic diagnosis of IRD. This will help inform patient prognosis and counselling in future clinical encounters.Methods: A comprehensive database of patients attending the tertiary referral clinic from 2011 to 2022 was compiled contemporaneously. Demographic data were collated from patients' clinical records. Subjects underwent genetic screening, including targeted gene sequencing, next‐generation sequencing‐based gene panel, or whole exome sequencing, to investigate the causative mutations.Results: A total of 365 probands (191 men and 174 women). The median age at which the patients developed visual symptoms related to IRD was 42 ± 17.7 years (range, 1–86 years). Retinitis pigmentosa (176; 48.2%), Macular Dystrophy (49; 13.4%), and Cone Rod Dystrophy (41; 11.2%) were the most common clinical diagnoses in this cohort. Among all the subjects, a genetic mutation was identified in 193 (52.9%) patients and the genetic aetiology of diseases was confirmed in 147 (40.3%) patients. Pathogenic mutations were identified in 48 retinal genes with the most commonly affected genes being ABCA4, USH2A and GUCY2D with 78, 44 and 13 mutations identified overall.Conclusions: The establishment of a molecular genetic diagnosis in this group of patients serves as a basis for genetic counselling and will allow patients to enrol in current and future gene‐based clinical trials, and benefit from any future gene‐based treatments.