OPTN and open-angle glaucoma: To date, four causative genes for POAG from 11 candidate chromosomal loci have been identified, including MYOC (myocilin), OPTN (optineurin), WDR36 (WD repeat domain 36), and CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), but these four genes together account for less than 10% of POAG cases [6-10].