Abstract: Objective To analyze mutations of CYP4V2 gene in a cohort of patients with Bietti crystalline corneoretinal dystrophy (BCD) and their clinical features. Design Retrospective case series. Participants 138 unrelated Chinese patients diagnosed with BCD in Beijing Tongren Hospital. Methods All study participants underwent a detailed ophthalmological examinations, mutational screening of CYP4V2 gene was examined via directional Sanger sequencing and real-time quantitative PCR. Main Outcome Measures Visual acuity, slit-lamp biomicroscopy, fundus photography, mutations of CYP4V2 gene. Results All patients were identified CYP4V2 mutation, the most frequent mutation in this cohort were c.802-810del17insCG, c.1091-2A>G and p.H331P. The average best corrected visual acuity (LogMAR) was 1.17±0.95 and average age of onset was 29.19±9.64 years old. The degree of visual impairment was related to the course of disease but not affected by the age of onset. Fundus photograph of all patients revealed typical crystalline deposits, the range and density of it was related to the course of disease. Conclusion Our findings expand the spectrum of CYP4V2 mutation. The clinical characteristic of BCD is obvious, and it could be effectively diagnosed with image manifestation methods. Identification of mutation gene lays foundation for provision of genetic consultation for BCD patients. （Ophthalmol CHN，2020, 29： 93-97）

Key words: Bietti crystalline corneoretinal dystrophy, CYP4V2 gene, gene mutation, clinical phenotype