AIM: To identify pathogenic mutations of CYP4V2 gene in two Chinese families with Bietti crystalline corneoretinal dystrophy(BCD)by Sanger sequencing.

METHODS: The relevant clinical examination of BCD patients were collected. Peripheral blood of patients and their family members was collected. Then DNA was extracted from peripheral blood, and Sanger sequencing was used to identify mutation sites.

RESULTS: Two probands of BCD from different families were collected. All the probands showed progressive decrease of visual acuity and typical crystal-like material deposition could be seen in the fundus. Sanger sequencing showed that proband 1 and her brother and sister all had homozygous mutation of c.802-8_810del17insGC in CYP4V2 gene. On the other hand, proband 2 had a compound heterozygous mutation of c.219T>A(p.F73L)and c.802-8_810del17insGC in CYP4V2 gene.

CONCLUSION: The most common mutation was c.802-8_810del17insGC in Chinese BCD patients. The homozygous c.802-8_810del17insGC mutation was the cause of BCD in the proband 1 family. On the other hand, proband 2 had c.802-8_810del17insGC heterozygous mutation and c. 219T>A(p.F73L)heterozygous missence mutation, all of which affected the normal coding of CYP4V2 gene and led to disease.