Lack of association of three primary open-angle glaucoma-susceptible loci with primary glaucomas in an Indian population

Nakano et al. (1) demonstrated significant association of six single nucleotide polymorphisms (SNPs) with primary open-angle glaucoma (POAG) that flanked genes on chromosomes 1 (ZP4), 10 (PLXDC2), and 12 (DKFZp762A217) in a Japanese population. The associations were consistent based on a two-stage genome-wide association study (GWAS) design, despite a mixture of both classical POAG [with raised intraocular pressure (IOP)] and normal-tension glaucoma (NTG) in their cohort. Genetic associations are biologically more meaningful if they are replicated across different ethnic groups (2). We tried to replicate these findings in 470 subjects from another Asian population (Indian) that included cases of POAG (n = 140) and ethnically matched normal controls (n = 219). A cohort of primary angle-closure glaucoma (PACG; n = 111) was also included to see whether these variations were also involved in another form of primary glaucoma. The regions harboring these SNPs were screened by resequencing and the variants further validated by restriction digestion.