Mutations in the myocilin gene in families with primary open-angle glaucoma and juvenile open-angle glaucoma.

OBJECTIVES: To investigate the prevalence of myocilin (MYOC) mutations in Italian families with glaucoma and to determine the relationship of these mutations to primary open-angle glaucoma (POAG), juvenile open-angle glaucoma (JOAG), and pigmentary dispersion glaucoma.

METHODS: Twenty-six patients with POAG were selected based on a positive family history of glaucoma. All patients and 210 relatives had an accurate clinical characterization.

MAIN OUTCOME MEASURE: Each index patient was screened by single-stranded conformational polymorphism analysis for mutations in the MYOC gene.

RESULTS: A MYOC gene mutation was found in 2 families. In one family, a previously reported p.K423E mutation was transmitted from the index patient with POAG to the 2 sons with JOAG. In the second family, a p.C25R change, affecting the signal peptide, was transmitted from the index patient with POAG to the son with JOAG, but not to the son with pigmentary dispersion glaucoma.

CONCLUSIONS: Clinical characterization of 2 families with MYOC gene mutations indicates that POAG and JOAG are the 2 sides of a continuum phenotypical spectrum due to a common molecular defect. On the other hand, our results confirm the different origin of pigmentary dispersion glaucoma.

CLINICAL RELEVANCE: Because MYOC gene mutations may be responsible for a fraction (2 [8%] of 26) of families with POAG/JOAG, a molecular genetic diagnosis should be included in the management of patients with glaucoma.