GST polymorphisms and early-onset coronary artery disease in young South African Indians

Abstract

Background. Glutathione S-transferases (GSTs) detoxify environmental agents which influence the onset and progression of disease. Dysfunctional detoxification enzymes are responsible for prolonged exposure to reactive molecules and can contribute to endothelial damage, an underlying factor in coronary artery disease (CAD).
Objectives. We aimed to assess 2 common polymorphic variant isoforms in GSTM1 and GSTP1 of GST in young CAD patients.
Methods. All patients (N=102) were South Africans of Indian ancestry, a population associated with high CAD risk. A corresponding age-, sex- and race-matched control group (N=100) was also recruited. Frequency of the GSTM1 +/0 (v. +/0 and 0/0) and GSTP1 A₁₀₅/G₁₀₅ (v. wild-type A₁₀₅/A₁₀₅) genotypes was assessed by differential polymerase chain reaction (PCR) and PCR restriction fragment length polymorphism (PCR-RFLP), respectively.
Results. The GSTM1 0/0 and GSTP1 A₁₀₅/A₁₀₅ genotypes occurred at higher frequencies in CAD patients compared with the control group (36% v. 18% and 65% v. 48%, respectively). A significant association with CAD was observed in GSTM1 0/0 (odds ratio (OR)=2.593; 95% confidence interval (CI) 1.353 - 4.971; p=0.0043) and GSTP1 A₁₀₅/A₁₀₅ OR=0.6011; 95% CI 0.3803 - 0.9503; p=0.0377). We found a significant association between smoking and CAD; the presence of either of the respective genotypes together with smoking increased the CAD risk (GSTP1 A₁₀₅ relative risk (RR)=1.382; 95% CI 0.958 - 1.994; p=0.0987 and GSTM1 null RR=1.725; 95% CI 1.044 - 2.851; p=0.0221).
Conclusion. Our findings support the association of genotypes GSTM1 0/0 and GSTP1 A₁₀₅/A₁₀₅ and smoking with CAD.

S Afr Med J 2012;102(7):627-630.