Keeping an eye on glaucoma

Glaucoma is the leading cause of irreversible blindness and affects millions worldwide. Patients with primary congenital glaucoma (PCG) often have mutations in the cytochrome P450 family 1, subfamily B, polypeptide 1 (CYP1B1) gene. In the March 7 Science, Richard Libby and colleagues report the characterization of a Cyp1b1^-/- knockout mouse as a model for PCG (Science, 299:1578-1581, March 7, 2003).

The mice had developmental eye defects similar to those seen in human patients. Genetic and histological analysis revealed a role for the tyrosinase gene as a genetic modifier. Tyrosinase also modifies the anterior segment dysgenesis phenotypes observed in mice lacking the Foxc1 gene that has also been implicated in PCG. Tyrosinase converts tyrosine to L-dopa, and the ocular phenotypes of the knockout mice could be relieved by the administration of L-dopa.

This study suggests that L-dopa should be tested as a possible therapeutic for treating glaucoma patients.