Association of polymorphisms in glutathione S-transferase genes （GSTM1, GSTT1, GSTP1） with idiopathic azoospermia or oligospermia in Sichuan, China

The reported effects of the glutathione S-transferase （GSTs） genes （GSTM1, GSTTI, and GSTP1） on male factor infertility have been inconsistent and even contradictory. Here, we conducted a case-control study to investigate the association between functionally important polymorphisms in GST genes and idiopathic male infertility. The study group consisted of 361 men with idiopathic azoospermia, 118 men with idiopathic oligospermia, and 234 age-matched healthy fertile male controls. Genomic DNA was extracted from the peripheral blood, and analyzed by polymerase chain reaction and restriction fragment length polymorphism analysis. There was a significant association between the GSTP1 variant genotype （lle/Val ＋ Val/Val） with idiopathic infertility risk （odds ratio [OR]： 1.53; 95% confidence interval [CI]： 1.11-2.11; P = 0.009）. Similarly, a higher risk of infertility was noted in individuals carrying a genotype combination of GSTTI-null and GSTP1 （lle/Val ＋ ValNal） （OR： 2.17; 95% Cl： 1.43-3.31; P = 0.0002）. These results suggest an increased risk of the GSTPI variant genotype （lle/Val ＋ Val/Val） for developing male factor infertility. Our findings also underrate the significance of the effect of GSTM1 and/or GSTT1 （especially the former） in modulating the risk of male infertility in males from Sichuan, southwest China.