Is the GSTM1 null polymorphism a risk factor in Primary Open Angle Glaucoma?

PURPOSE To investigate the association of glutathione S-transferase (GST) GSTM1, GSTT1, and GSTP1 genes with the risk of primary open angle glaucoma (POAG) and clinical features of the disease. METHODS We conducted a case-control study that included 87 Brazilian patients with POAG and 85 healthy controls matched for age, ethnicity, and sex, whose blood samples were genotyped for polymorphisms in GST genes using polymerase chain reaction (PCR) based methods. RESULTS The GSTM1 null polymorphism was significantly more common in the POAG than in the controls group (OR: 2.1, 95% CI: 1.13-3.9; p=0.018). The combined GSTM1 null/GSTT1+ genotype and GSTM1 null/GSTP1 Ile/Val or Val/Val was more prevalent in POAG patients, being a risk factor for POAG (OR: 2.4, 95% CI: 1.16-4.9; p=0.016 and OR: 2.7, 95% CI: 1.07-6.74; p=0.033, respectively). The GSTM1 null/GSTT1+ genotype were associated with higher levels of IOP of both eyes and with more severe defect of the right eye optic nerve. The GSTM1 null/GSTP1 Ile/Val or Val/Val genotypes were associated with higher levels of IOP and more advanced defect of the right eye optic nerve and visual field. CONCLUSIONS We demonstrate that GSTM1 null polymorphism is associated with POAG in the Brazilian population.