Molecular Analysis of the Myocilin Gene in Chinese Subjects with Chronic Primary-angle Closure Glaucoma

Purpose: Mutations in the myocilin (MYOC) gene have been implicated in juvenile as well as late-onset primary open-angle glaucoma (POAG). Overall, MYOC mutations account for 3% to 5% of cases of POAG worldwide, making it the most significant gene identified so far in glaucoma. Although there are some similarities in the phenotype of POAG and in particular chronic primary angle-closure glaucoma (PACG), little is known about the role of MYOC in the causation of PACG. To address this, the MYOC gene was screened in a cohort of 106 patients with chronic PACG.

Methods: Genomic DNA was extracted from leukocytes of the peripheral blood and exons 1 to 3 of the MYOC gene were PCR amplified and subjected to bidirectional sequencing and analysis.

Results: One hundred six patients with chronic PACG of Chinese ethnicity were studied. Sequencing of the MYOC gene in these patients revealed eight sequence variants. Of these, one was a nonsense change, three were missense changes, two were synonymous codon changes, and two were changes in noncoding sequences. These included the Arg46Stop and Thr353Ile mutations, which have been reported in individuals with POAG. However, all the sequence alterations identified have been found in normal Chinese subjects.

Conclusions: The results of this study do not support a role for MYOC mutations in the pathogenesis of chronic PACG in the Chinese.