ATSN-201 Gene Therapy in RS1-Associated X-linked Retinoschisis

This trial is testing ATSN-201, a gene therapy delivered directly into the eye, for X-linked retinoschisis (XLRS) — a rare inherited eye condition that almost exclusively affects males. XLRS is caused by mutations in the RS1 gene, which provides instructions for a protein that helps maintain the structure of the retina. Without this protein, the retinal layers split apart, leading to progressive vision loss starting in childhood. Gene therapy aims to deliver a working copy of RS1 directly to retinal cells. Male patients are eligible if they are at least 6 years old (adults for early cohorts, children aged 6-17 for a later cohort), have a confirmed RS1 gene mutation causing XLRS, and have vision in the study eye between 20/200 and 20/40. Those with pre-existing eye conditions that increase injection risk, recent eye surgery, or prior participation in an eye gene therapy trial are excluded. Participants receive a single subretinal injection of ATSN-201 in one eye and are monitored for safety and vision changes over a year. Gene therapy for inherited retinal diseases is one of the most promising frontiers in ophthalmology — this study could offer patients with XLRS a treatment that slows or even reverses their vision loss for the first time.