Although treatment effects have been observed with improved light sensitivity and mobility after subretinal administration of AAV-RPE65 gene complex in both animal models with RPE65 mutations and RPE65-LCA patients, the improved visual function started declining 3 years after treatment and this gene therapy approach could not prevent progress of retinal degeneration with photoreceptor apoptosis, which eventually leads to retinal cell loss including RPE cells and photoreceptors. The gene discussed is RPE65; the disease is Leber congenital amaurosis.