Association of GSTT1 and GSTM1 polymorphisms with early pregnancy loss in an Indian population and a meta-analysis

Glutathione S-transferase theta 1 (GSTT1) and glutathione S-transferase Mu 1 (GSTM1) enzymes of the glutathione detoxification pathway protect the embryo from oxidative stress. This study investigated GSTT1 and GSTM1 in relation to their role in conferring genetic susceptibility to pregnancy loss. In a case-control study, 174 early pregnancy loss (EPL) patients, of which 130 were recurrent pregnancy loss (RPL) patients, and 180 healthy controls were investigated. Null genotypes of GSTT1 and GSTM1 were identified in duplex PCR reaction systems. Age-adjusted odds ratios (aOR) were calculated by logistic regression analysis. A meta-analysis was also conducted. The GSTT1 null genotype was significantly associated with EPL (aOR 4.47, P=0.004) and RPL (aOR 4.39, P=0.006). No significant association of the GSTM1 null genotype was found with RPL. In a meta-analysis study, the presence of the GSTM1 null genotype was shown to be a risk for RPL. The GSTT1 null genotype was not found to be a risk factor for pregnancy loss in the pooled population but its association with RPL was found in the Indian population. This study suggests that women carriers of GSTT1 and GSTM1 null genotypes are more often at genetic risk of pregnancy loss. Glutathione S-transferase theta 1 (GSTT1) and glutathione S-transferase mu 1 (GSTM1), enzymes of detoxification pathway, protect the embryo from oxidative stress. In the present study we have investigated GSTT1 and GSTM1 in relation to their role in conferring genetic susceptibility for early pregnancy loss (EPL) and recurrent pregnancy loss (RPL). Meta-analysis on the polymorphisms was conducted to support our findings that the presence of mutant genotypes at this site increases the risk of pregnancy loss. The GSTT1 null genotype was significantly associated with both EPL and RPL. In the meta-analysis, the overall result showed that the association between GSTM1 null genotype and risk for RPL was statistically significant. On comparing the GSTT1 studies, great heterogeneity was found between studies. A subgroup analysis was performed based on ethnicity. Our results showed a significantly increased risk with the GSTT1 null genotype in the Indian population, but no risk was found in the pooled population. In conclusion, the data of the present study clearly suggest that GSTT1 and GSTM1 polymorphisms are genetic risk factors for pregnancy loss in the study population.