Natural History Study of Patients With EYS-Associated RP

This natural history study of patients with EYS mutations from Russia and former CIS (Commonwealth of Independent States) territories will accelerate the development of outcome measures for clinical trials. Sensitive, reliable outcome measures of retinal degeneration will greatly facilitate development of treatments for retinitis pigmentosa due to EYS mutations. This approach helps to develop experimental treatment protocol, and assessing its effectiveness. The goals and expected impact of this natural history study are to: 1. Describe the natural history of retinal degeneration in patients with biallelic mutations in EYS gene in Russia and former CIS territories. 2. Identify sensitive structural and functional outcome measures to use for future multicenter clinical trials in EYS-related retinal degeneration in Russia and former CIS territories. 3. Identify well-defined subpopulations for future clinical trials of investigative treatments for EYS-related retinal degeneration in Russia and former CIS territories.

1. Characterize the natural history of retinal degeneration associated with biallelic pathogenic mutations in the EYS gene over 4 years, as measured using functional, structural, and patient-reported outcome measures 2. Investigate whether structural outcome measures can be validated as surrogates for functional outcomes in individuals with biallelic pathogenic mutations in the EYS gene 3. Evaluate risk factors (genotype, phenotype, environmental, and comorbidities) for progression of the outcome measures at 4 years in individuals with biallelic pathogenic mutations in the EYS gene 4. Evaluate variability and symmetry of left and right eye outcomes over 4 years in individuals with biallelic pathogenic mutations in the EYS gene