OPTN and open-angle glaucoma: To date, three causative genes have been identified for POAG, namely myocilin (MYOC) on chromosome 1q24.3 (GLC1A) [2], optineurin (OPTN) on chromosome 10p15–14 (GLC1E) [3], and WD repeat domain 36 (WDR36) on chromosome 5q22.1 (GLC1G), which account for less than 10% of POAG cases [4].