The article describes a phase 1/2 study of EDIT-101, which is administered by subretinal injection in patients with hereditary retinal degeneration caused by the IVS26 variant in the CEP290 gene.[1] The primary objective was safety, including adverse events and dose-limiting toxicities; there were no treatment- or procedure-related serious adverse events and no dose-limiting toxic effects.[1] Six participants had a meaningful improvement from baseline in the mobility test.[1] An additional six participants showed meaningful improvement in vision-related quality of life scores.[1] The safety profile and improvements in photoreceptor function support further in vivo investigations of CRISPR/Cas9 gene editing to treat inherited retinal degenerations caused by this CEP290 variant and other genetic causes.[1] The greatest benefit of EDIT-101 was in younger participants with severe visual impairment before the intervention, and the treatment is likely to be most effective early in the disease.[1] Recruitment to the study was terminated early; with a larger number of children, the effect on visual acuity could be more consistent.[1] Genetic diseases of the retina cause visual impairment in millions of children and adults worldwide.[1]