Glaucomas are a heterogeneous group of eye conditions with manifestation from as early as birth to very late age of onset in life. The primary type of these conditions affecting children and juveniles are less frequent, but the prevalence of glaucomas affecting older people of > or = 70 years progressively rises to approximately 5%. The molecular genetics of three types of glaucoma have been the subject of investigation in the last few years. As a result, two loci (GLC3A and GLC3B) have been identified for primary congenital glaucoma, one locus (GLC1A) for juvenile-onset primary open angle glaucoma and a further two loci (GLC1B and GLC1C) for late-onset chronic open angle glaucoma. Early this year, the first set of mutations was described in the CYP1B1 (Cytochrome P4501B1) and TIGR (Trabecular meshwork Inducible Glucocorticoid Response Protein) genes for the GLC3A and GLC1A-linked families, respectively. The mapping of different types of glaucoma and mutation identification in these two genes are the focus of this review.