A GLC1A gene Gln368Stop mutation in a patient with normal-tension open-angle glaucoma.

PURPOSE: To present a case involving a patient with normal-tension glaucoma with a Gln368Stop mutation of the myocilin/trabecular meshwork inducible glucocorticoid response protein (MYOC/TIGR) gene.

METHODS

Slit-lamp biomicroscopic and gonioscopic examination, morphometry of the optic disc, 24-hour intraocular pressure (IOP) profile, and perimetry were performed to determine the phenotype of the patient. Neurologic examination and a computed tomographic (CT) scan of the brain were performed to rule out a neurologic disorder. Single-strand confirmation polymorphism (SSCP) analysis and subsequent sequence analysis of blood was performed for genotyping of the GLC1A gene.

RESULTS

A nonsense codon, namely a Gln368Stop mutation in the third exon of the GLC1A gene, was found in this patient with normal-tension glaucoma.

CONCLUSION

In contrast to previous reports, a Gln368Stop mutation of the GLC1A gene need not be confined to patients with glaucomatous optic atrophy due to high IOP. The pathogenesis of glaucoma associated with GLC1A gene mutations might be more complex than expected, and (unknown) suppressor mechanisms have to be considered.