Clinical and Population-Specific Insights Into Inherited Retinal Dystrophies From Whole-Exome Sequencing of the Polish Cohort

Purpose: Inherited retinal dystrophies (IRDs) are a diverse group of genetic disorders that lead to progressive vision loss, with non-syndromic and syndromic retinitis pigmentosa (RP) being one of the most common and genetically heterogeneous forms. This study aimed to explore the genetic landscape of IRDs in the white Polish cohort. Methods: A total of 203 individuals were recruited, including 159 with RP, 21 with Usher syndrome, 16 with cone-rod dystrophy, four with Bardet-Biedl syndrome, and three with Leber congenital amaurosis. Whole-exome sequencing (WES) was used to identify pathogenic variants associated with IRDs. Results: Pathogenic variants were detected in 132 participants (65.0%), with a diagnostic yield of 63.7% for RP-related mutations. The most frequent causative variants were located in the ABCA4 and USH2A genes, which accounted for 24% and 16% of the identified variants, respectively. Additionally, 24 novel variants of diverse molecular character were identified, including large deletions and frameshift mutations, reflecting substantial heterogeneity in their molecular nature. Conclusions: This comprehensive genetic analysis not only supports the molecular diagnosis of IRDs in the Polish population but also highlights the usefulness of WES in determining the genetic causes of hereditary retinal dystrophies and identifying new causative variants. Consequently, a dedicated gene panel will be developed to support molecular diagnosis of RP and related IRDs. The collected clinical, imaging, and genetic data may also be useful for future analyses integrating genotype-phenotype correlations, as well as phenotype-phenotype correlations.