A Novel Mutation In The CYP4V2 Gene In A Japanese Patient With Bietti’s Crystalline Corneoretinal Dystrophy

Abstract

Purpose: : To describe the clinical and genetic characteristics of a Japanese family including a patient with Bietti’s crystalline corneoretinal dystrophy (BCD).

Methods: : Mutation screening was performed in the CYP4V2 gene on a patient with BCD and her daughter. Genomic DNA was extracted from peripheral blood leucocytes. The coding region (including intron-exon boundary) of the CYP4V2 gene was amplified by polymerase chain reaction. The PCR products were analyzed using direct sequencing. The clinical features were revealed by the visual acuity, slit-lamp examination, fundus examination, fluorescein angiography, Goldmann perimetry (GP) and electroretinography (ERG).

Results: : The patient was a 64-year-old female. Her visual acuity was 0.4, bilaterally. Slit lamp examination was revealed crystalline-like deposits at the superior limbus of the cornea, bilaterally. Fundus examination disclosed chorioretinal atrophy and numerous glistening yellowish white crystalline deposits scattered throughout the posterior pole and mid-peripheral retina. Standard flash ERG showed an extinguished type. Relative scotoma was detected by GP. Genetic analysis revealed that she had a heterozygous mutation in the CYP4V2 gene (IVS6-8del TCATACAGGTCATCGCG/GC) which is most commonly found in Japanese patients with BCD. Furthermore, she had a novel heterozygous mutation in the CYP4V2 gene (1168C→T). Her daughter who has no clinical findings of BCD has only the same heterozygous mutation in the CYP4V2 gene (1168C→T).

Conclusions: : We determined that this patient had a compound heterozygote with two mutations in the CYP4V2 gene. The 1186→T mutation in the CYP4V2 has not been previously reported. This mutation causes a missense mutation (R390C) in the CYP4V2 protein.

Keywords: gene screening • retinal degenerations: hereditary • genetics