Inherited retinal diseases (IRDs) are a group of degenerative disorders that cause progressive vision loss. Retinitis pigmentosa (RP) is the most common form, with a global prevalence of approximately 1 in 4,500. About 20-30% of these cases are syndromic, most notably Usher syndrome (USH), which combines hearing loss with visual impairment. Usher syndrome type 1 (USH1), the most severe form, presents at birth with profound sensorineural hearing loss, vestibular areflexia, and early-onset retinal degeneration. Biallelic mutations in the MYO7A gene, which define the USH1B subtype, account for 70% of USH1 cases. There is currently no treatment available for this serious condition. The objective of the study is to characterize the natural history of retinal degeneration in USH1B patients and to validate functional vision tests using virtual reality and patient-reported outcome questionnaires.
Be at least 3 years old;
Have a clinical diagnosis of USH1 in both eyes, meaning subjects with congenital profound deafness, vestibular dysfunction, and rod dystrophy, carrying biallelic class 4 or 5 variants in the MYO7A gene;
Be affiliated with or beneficiary of a social security system (according to article L1121-8-1 of the French Public Health Code);
Sufficient knowledge of spoken and signed French to ensure understanding of tasks and instructions;
Unable to participate in all study visits;
Expected to enter an experimental treatment trial at any time during this study;
Presence of ocular conditions that may affect eye status other than retinitis pigmentosa (e.g., history of retinal detachment, glaucoma, vein occlusion, diabetic retinopathy, etc.);
Participation in the previous gene replacement trial (USHSTAT, NCT01505062);