Apolipoprotein C3 SstI polymorphism and triglyceride levels in Asian Indians

DNA samples were analyzed by polymerase chain reaction (PCR) followed by SstI digestion. Digested PCR products were run on 3% agarose gel and visualized by ethidium bromide staining.Rare S2 allele was highly prevalent in our study population (0.313) as compared to the Caucasians (0.00–0.11). The genotypic distribution was in agreement with Hardy-Weinberg equilibrium. S2 allele was almost two times more prevalent in the HTG group (N = 34) as compared to NTG group (N = 105) (p = 0.001). Multiple logistic regression revealed S1S2 individuals had age-adjusted odds ratio of 2.43 (95%CI = 0.99–6.01, p = 0.054) and S2S2 had 9.9 (95%CI = 2.66–37.29, p = 0.0006) for developing HTG in comparison to S1S1 genotype.Our study shows a significant association between rare S2 allele and HTG in Asian Indians.Apolipoprotein CIII (apoCIII protein; APOC3 gene) is a 79 amino acids long glycoprotein that is synthesized predominantly in the liver and to a lesser degree in the intestine [1]. It is present on very low density lipoproteins (VLDLs) and chylomicron remnants; and to some extent on high density lipoproteins (HDLs) [1]. Although the precise function of apoCIII is not clearly understood, several lines of evidence suggest its involvement in the regulation of triglyceride (TG) levels. In vitro, apoCIII inhibits lipoprotein lipase (LPL), a rate-limiting enzyme for TG hydrolysis, resulting in the delayed catabolism of TG-rich particles [2]. Furthermore, it also decreases apoE-mediated remnant removal by displacement of apoE from the VLDL particles in vivo [3,4]. Additional copies of human APOC3 gene in transgenic mice were associated with hypertriglyceridemia (HTG) [5], whereas the absence of the gene in knock out mice leads to reduced TG [6].APOC3 gene has been mapped on the long arm of chromosome11, closely linked to the APOA4 and APOA1 genes [7]. A transversion from C to G in the 3' untranslated region (3'UTR) of exon 4 in the APOC3 gene results in an SstI polymorphism. Several stud