Glutathione S-transferase (GSTM1, GSTT1) polymorphisms and JOAG susceptibility: A case control study and meta-analysis in glaucoma

Purpose: Glutathione S transferase (GST) polymorphisms have been considered risk factors for the development of glaucoma. The aim of the present study was to investigate the association of glutathione S-transferase GSTT1 and GSTM1 genotypes with juvenile open-angle glaucoma (JOAG) in Indian patients. Methods: A case-control study was performed to investigate the associations of GSTM1 and GSTT1 in juvenile open-angle glaucoma. The genotype of GSTM1 and GSTT1 were determined in 73 juvenile open-angle glaucoma patients, and 70 controls matched by age and sex by polymerase chain reaction method. We also performed a meta-analysis of sixteen published studies on GSTM1 and GSTT1 and evaluated the association between the GSTM1 and GSTT1 polymorphisms and glaucoma (JOAG & POAG). Published literature from PubMed and other databases were retrieved. All studies evaluating the association between GSTMI and GSTT1 polymorphisms and glaucoma (JOAG & POAG) risk were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using random- or fixed-effects model. Results: In the present study, we observed there is no association of GSTMI (OR = 0.680; 95% CI = 0.323-1.433; p = 0.311) or GSTT1 (OR = 0.698; 95% CI = 0.307-1.586; p = 0.391) with JOAG. In the present meta-analysis, significantly increased glaucoma (JOAG & POAG) risk was found among subjects carrying GSTM1 null genotype (OR = 1.177; 95% CI = 1.028-1.348; p = 0.018) but not among subjects carrying GSTT1 deletion genotype (OR = 1.186; 95% CI = 0.992-1.417; p = 0.061). Conclusions: The present case-control study found that GSTM1 and GSTT1 polymorphism are not associated with JOAG risk in North Indian population. The present meta-analysis suggested that there might be a significant association of GSTM1 null genotype with glaucoma (JOAG & POAG) risk. To the best of our knowledge, this is the first study in the world to investigate role of GSTM1 and GSTT1 polymorphisms with JOAG susceptibility. Given the limited sample size, the associations between GST polymorphism and glaucoma risk needs further investigation.