CYP4V2 and Bietti crystalline corneoretinal dystrophy: To our knowledge, this study provides the first 1-year follow-up results of a gene therapy clinical trial for BCD, which is caused by mutations in CYP4V2 as the most common disease-causing gene for IRDs in China.17 Subretinal injection of rAAV2/8-hCYP4V2 showed a favorable safety profile, without inflammatory responses or treatment-related serious adverse events, and both subjective and objective measurements of visual function continued to improve within 1 year after administration.