Linkage studies of familial and congenital glaucoma have shown the existence of genes with a significant effect on the disease, such as MYOC (myocilin) and OPTN (optineurin) for familial primary open-angle glaucoma (POAG) and CYP1B1 for congenital glaucoma (Stoilov et al., 1997; Stone et al., 1997). The gene discussed is CYP1B1; the disease is congenital glaucoma.