Identification of a new GLC1A mutation in a sporadic, primary open-angle glaucoma in Japan

Glaucoma is a major cause of blindness characterized by progressive degeneration of the optic nerve and elevated intraocular pressure. Recent studies have revealed a genetic basis for a substantial proportion of cases of familial primary open-angle glaucoma (POAG) and the gene causing the abnormality has been identified. Sequence variations that meet the criteria for a probable disease-causing mutation have been found in the American and European populations. In this study, we examined 58 cases of sporadic glaucoma from Japan to clarify the relationship between the mutations of the GLC1A gene and sporadic glaucoma in Japan. We have examined 33 POAG, 17 primary closed-angle glaucomas, 6 normal-tension glaucomas and 2 steroidinduced glaucomas for mutation of the GLC1A gene using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct DNA sequencing studies. We identified a previously unreported GGT→GAT transition at codon 451 in exon 3, resulting in a glycine to asparagine substitution in one POAG patient. No other mutations of the GLC1A gene were found in other types of glaucoma. These findings further emphasize the importance of GLC1A mutation in the development of POAG.