Association of the SIX6 locus with primary open angle glaucoma in southern Chinese and Japanese.

The purpose of the study was to evaluate the association profiles of the SIX6 locus with primary open-angle glaucoma (POAG) in southern Chinese and Japanese. In this study, we tested single marker and haplotype-based associations of 11 tagging single nucleotide polymorphisms (SNPs) covering the SIX6 locus with POAG in a Hong Kong Chinese cohort (N = 1402). A novel SNP (i.e., rs12436579) and two SNPs (i.e., rs33912345 and rs10483727) from previous genome-wide association studies were further tested in a Chinese cohort from Shantou (N = 888) and a Japanese cohort from Osaka (N = 463). Results from the three cohorts were meta-analysed using a random-effect model. We found rs12436579, which has not been previously reported, was associated with POAG in Hong Kong and Shantou Chinese (Pcombined = 4.3 × 10-5, OR = 0.72, I2 = 0). Additionally, we replicated the association of one known SNP, rs33912345 (Pcombined = 0.0061, OR = 0.69, I2 = 45%), with POAG in the Chinese cohorts but not in the Japanese cohort (P > 0.6). Another known SNP, rs10483727, was nominally associated with POAG in the two Chinese cohorts (Pcombined = 0.017, OR = 0.70, I2 = 53%). All these three SNPs were significantly associated with POAG when the three cohorts were combined in meta-analysis (Pcombined<0.005). Furthermore, two haplotypes, C-C (Pcombined = 1.13 × 10-5, OR = 1.41, I2 = 0) and A-A (Pcombined = 0.045, OR = 0.68, I2 = 70%), defined by rs33912345-rs12436579 were associated with POAG in Chinese but not in Japanese. In conclusion, this study confirmed the association between two GWAS SNPs in SIX6 (rs33912345 and rs10483727) and POAG. Also, a SNP, rs12436579, not associated with POAG before, was found to be associated with POAG in Chinese. Further studies are warranted to elucidate the role of this novel SNP in POAG.