Paraoxonase gene polymorphism and coronary artery disease in Indian subjects

The human serum HDL-linked paraoxonase enzyme limits the LDL peroxidation by preventing transformation of LDL into biologically active atherogenic particles. Paraoxonase serum activity varies among individuals due to an Gln/Arg polymorphism with low (A phenotype) and high activity (B phenotype). The present study correlates the paraoxonase enzyme activity and the paraoxonase gene polymorphism among 200 Indians with or without coronary artery disease (CAD). We analyzed the PON enzyme activity and have identified A and B phenotypes by Alwl restriction mapping. In 120 CAD patients, the genotypes A and B constituted 75 and 25%, where as in 80 control subjects, the genotypes A and B constituted 25 and 17%, respectively. The frequency of AB genotype is higher in CAD subjects with or without diabetes, than in controls. Arg allele frequency was higher (0.45) in CAD subjects than in controls (0.17). The conventional risk factors and the family history of CAD did not affect the genotype frequency distribution among Indians. In conclusion, paraoxonase polymorphism may have been involved in the predisposition to CAD through a mechanism other than lipid oxidation.