Genetic and Clinical Heterogeneity of Polish Patients with Congenital Stationary Night Blindness (CSNB).

Congenital stationary night blindness (CSNB) is a rare, genetically and clinically heterogeneous group of non-progressive inherited retinal diseases characterized by night blindness, myopia, nystagmus, and decreased visual acuity, for which comprehensive genetic characterization remains essential to enable accurate diagnosis and future gene therapy development. In this study, we performed a clinical and genetic analysis of twenty-one Polish families diagnosed with CSNB using next-generation sequencing (NGS)-based targeted gene panels and, in one case, whole-exome sequencing (WES), complemented by Sanger sequencing for variant validation and segregation analysis. Pathogenic variants were identified in six genes: GPR179 and NYX were the most frequently affected (six families each), followed by CACNA1F (three families), GRM6, TRPM1, and SLC24A1 (two families each). The complete Schubert-Bornschein form predominated in our cohort, in contrast to previous reports indicating higher prevalence of the incomplete form. Notably, ten previously unreported variants were identified in CACNA1F, GRM6, and NYX, expanding the known mutational spectrum of CSNB. Certain variants appear enriched in the Polish population. These findings underscore the value of NGS-based approaches for precise molecular diagnosis of CSNB and contribute to the broader understanding of its genetic architecture.