Glutathione S-Transferase Gene Polymorphism as a Susceptibility Factor for Acute Myocardial Infarction and Smoking in the North Indian Population

Abstract

<i>Objectives:</i> Glutathione S-transferase <i>(GST)</i> plays a key role in the detoxification of xenobiotic atherogens generated by smoking. We investigated whether functional <i>GST</i> gene polymorphism might be associated with acute myocardial infarction (AMI) and smoking. No such investigation has previously been conducted among North Indians. <i>Methods:</i> 230 patients with AMI and 300 healthy controls of North Indian ethnicity were enrolled in the study. <i>GSTM1/T1/P1 </i>gene polymorphisms were examined using restriction fragment length polymorphism. <i>Results:</i> When <i>GST</i> polymorphism was analyzed in patients with AMI, <i>GSTM1</i> null genotype frequencies were 0.24 and 0.21 among cases with coronary artery disease and controls, respectively. The respective <i>GSTT1</i> null genotype frequencies were 0.10 and 0.20 (p = 0.001). <i>GSTP1 </i>variant Val/Val allele frequencies were 0.02 and 0.07 with p = 0.03. After risk factor adjustment, only <i>GSTP1</i><i>Val/Val</i> was found to be protective against disease. Considering the effect of <i>GST (T1, M1, </i>and<i> P1) </i>gene polymorphism on smoking, subjects were further divided into smokers and nonsmokers. However, <i>GSTT1</i> null as well as <i>GSTP Val/Val</i> genotypes were protective only in nonsmokers (p = 0.01 and p = 0.04). <i>Conclusions:</i> A significant protective effect of <i>GSTT1</i> null and <i>GSTP1 Val</i> genotype against disease was observed in patients with AMI although protection was limited to nonsmokers.