Background: Myocilin is a gene that causes primary open-angle glaucoma(POAG). We found a family with normal tension glaucoma(NTG) whose members had an Asp 208 Glu mutation, and a family with POAG whose members had an Ile 360 Asn mutation in myocilin.
Case: In the family with the Asp 208 Glu mutation, the proband, a 31-year-old male, was diagnosed as having NTG. His mother had the same mutation and was also diagnosed as having NTG, but a sister with the same mutation showed no glaucomatous changes. We also found this mutation in normal controls. In the family with the Ile 360 Asn mutation, the proband, a 67-year-old female, was diagnosed as having POAG. Four members of this family showed different phenotypes including POAG, ocular hypertension, and normal. We found no cases with the same mutation in the controls.
Conclusion: Since the Asp 208 Glu mutation was found in NTG, the pathogenesis of glaucoma with myocilin mutation might be more complex and it may be related to weakness of the optic nerve head. On the other hand, the mutation may be a polymorphism. The Ile 360 Asn mutation was considered to be disease-causing. However, both late-onset glaucoma cases and non-glaucomatous cases were observed in this family. The implications of the mutation and other risk factors remain to be discussed.