Nakano et al. demonstrated significant association of six SNPs with POAG that flanked genes on chromosomes 1 (zona pellucida glycoprotein 4; ZP4), 10 (plexin domain containing 2; PLXDC2), and 12 (transmembrane and tetratricopeptide repeat containing 2; TMTC2) in a Japanese population [17], but a subsequent replication study in an Indian population did not confirm this finding [41]. This evidence concerns the gene TMTC2 and open-angle glaucoma.