Notably the contribution of CYP1B1, which is usually associated with PCG, to JOAG has been shown to be very significant in Iran.14,23 In fact, MYOC and CYP1B1 may contribute equally to JOAG status among Iranian patients.14 The explanation for this may be that some cases of JOAG may be late onset forms of PCG rather than early onset forms of POAG. The gene discussed is CYP1B1; the disease is open-angle glaucoma.