Are Common Polymorphisms of the Lipoprotein Lipase and Human Paraoxonase-1 Genes Associated with the Metabolic Syndrome in South African Asian Indians?

Abstract

A cross-sectional study was performed to determine the possible contribution of the Human Paraoxonase-1 (PON1) and Lipoprotein Lipase (LPL) polymorphisms to the risk of the metabolic syndrome (MetS) in 817 participants of South African Asian Indian ancestry. Demographic and anthropometric data, including fasting blood for analysis of glycaemic and lipid parameters was collected. DNA was isolated from peripheral blood and allelic polymorphisms at positions Q192R, L55M in the PON1 gene and S447X and N291S in the LPL gene were studied using real-time PCR. Melting curve analysis was used to identify homozygotes and heterozygotes. The MetS was classified using the harmonised criteria. The prevalence of the MetS was 47.99%, with the main drivers being the increased waist circumference (96.6%), raised blood pressure (76.8%) and raised triglyceride levels (72.4%). There was no significant difference (p=n/s) in the distribution of the genotypes as well as their alleles in subjects with and without MetS. Increased levels of triglycerides was found in subjects with the MetS who had the QQ (p=0.007; OR=1.19; 95%CI=1.04; 1.36) and QR (p=0.018; OR=1.73; 95% CI=1.12; 2.67) genotypes of the Q192R polymorphisms. Subjects who had both the SX genotype (S447X polymorphism) and the LM genotype (L55M polymorphism) were more likely to have the MetS than those without (p=0.016; OR 2.19; 95% CI: 1.17, 4.06). Interactions involving the PON 1 gene may predispose to the MetS and to its component risk factors such as hypertriglyceridemia in this population. Environmental factors, such as lifestyle behaviour patterns appear to be the main driver contributing to obesity-related MetS.