MYOC and open-angle glaucoma: In a recent study, it was found that mutations in CYP1B1 alone can be underlying cause in POAG.108 In addition, there is growing body of evidence suggesting that there exists some functional interaction between CYP1B1 and MYOC34 and this fact further lends support to the observation that PCG can also be caused by mutations in MYOC (MYOC playing the role of a potential modifier gene).107 This digenic inheritance engrossing both MYOC and CYP1B1 immediately indicates the role of MYOC in PCG (PCG in this case being allelic variant of POAG).