OPTN and open-angle glaucoma: It has been estimated that variants in at least five of the genes identified through linkage studies of Mendelian POAG (MYOC, OPTN, WDR36, CYP1B1, ASB10) may account for up to 10% of the heritability of complex POAG cases, suggesting that discovery of additional genes for monogenic forms of POAG may enhance understanding of the genetic architecture of complex POAG.