Lack of association of mutations of the bestrophin gene with age-related macular degeneration in non-familial Japanese patients

Background: Heterozygous mutations of the bestrophin gene are associated with Best macular dystrophy (BMD). The bestrophin gene is specifically expressed in the retinal pigment epithelium. BMD is a hereditary form of macular degeneration that may develop subretinal neovascularisation similar to the wet type of age-related macular degeneration (AMD). Purpose: To study whether mutations of the bestrophin gene occur in non-familial Japanese AMD patients. Methods: A total of 85 non-familial AMD patients (average age 67.5 years; 72 male, 14 female) diagnosed by indocyanine green angiography were screened. Among them, 69 patients (81%) were classified as having wet type AMD. Genomic DNA was purified from the total blood and used as the template for polymerase chain reaction (PCR). All the exons of bestrophin gene were amplified by PCR. Mutation analysis was performed by SSCP using the ABI Prism 310 Genetic Analyzer (Perkin Elmer). Nucleotide sequence was determined by direct sequencing of the PCR amplicons. As the control, 105 non-AMD patients (average age 62.0 years; 52 male, 53 female) were screened by the same method. Results: Only one AMD patient had a specific polymorphism in exon 2, but no mutations leading to amino acid substitutions were found. In exon 2 and 3, two further polymorphisms were detected in all AMD patients as well as normal controls. Conclusion: No mutations were found in the bestrophin gene in nonfamilial Japanese patients with AMD or in normal controls.