State-of-the-art Strategies To Genetically Investigate A Novel Cohort With Retinal Disorders In France

Abstract

Purpose: : To genetically investigate over 1000 index patients and family members with inherited retinopathies of which the majority represents RP (67% arRP, 26% adRP and 7% xlRP).

Methods: : Microarrays (ASPER Ophthalmics), homozygosity mapping, linkage analysis, Sanger and next-generation-sequencing (NGS) were performed. We also developed a NGS-retinal panel with over 250 known and candidate genes.

Results: : The micoarray analysis revealed in 22% of simplex or arRP cases at least one variant, which was confirmed for its pathogenicity. As it has been reported for other cohorts, USH2A is the most frequently mutated gene in this cohort. Direct sequencing of EYS and C2orf71 in patients excluded for known variants revealed at least one mutation in ~12% and ~1% cases respectively. Direct sequencing of RHO, PRFP31, PRPH2 and RP1 revealed in 16.5%, 6.7%, 9% and 6% of adRP cases a known or novel mutation. Additional microarray analysis in the excluded cases detected known NR2E3 mutations in 4,5% of cases and PRPF3, PRPF8 and ROM1 mutations, each in 1,5% of cases. Linkage analysis of a large adRP family revealed a novel locus. Exon capture of the targeted region followed by NGS results will be presented along with homozygosity mapping and the NGS-retinal panel data.

Conclusions: : Based on a comprehensive analysis, mutations have been identified in ~40% of patients of the cohort. The remaining patients represent a unique clinical resource for the identification of novel genes implicated in retinal dystrophies.

Keywords: retinal degenerations: hereditary • gene screening • genetics