L55M and Q192R polymorphism of Paraoxonase gene and the risk of myocardial infarction in South Indian Tamil population

Abstract

Paraoxonase, also known as aromatic esterase 1 encoded by PON1 gene is a high density lipoprotein linked enzyme that possess antiatherogenic activity. It protects low density lipoprotein (LDL) from oxidation and destroys biologically active oxidized lipids on lipoproteins and in arterial cells. Polymorphisms in PON1 gene, L55M and Q192R on exon 3 and 6 respectively are known to be risk in causing cardiovascular diseases. The study was aimed to determine the association of L55M and Q192R in pathogenicity of myocardial infarction in South Indian Tamil population. Tetra primer Amplification Refractory Mutation System–PCR method uses allele specific primer to discriminate the L55M and Q192R alleles. Total of 350 individuals enrolled at SRM Medical college hospital were considered for the study (200 MI patients and 150 age, sex matched controls). The genotype frequency in the population for L55M is LL=0.49, LM=0.40, MM=0.10, for Q192R is QQ=0.38, QR=0.46, RR=0.15 and it is consistent with Hardy-Weinberg equilibrium. The Logistic regression analysis showed MM vs LL having OR=1.44, M vs L OR=1.56 stating M allele is associated with developing risks of MI. In Q192R, RR vs QQ OR=3.25, R vs Q, OR=1.88 showing R allele having 3 times higher risk in developing MI.