High concentration of apolipoprotein B (apoB) is a risk factor for coronary artery disease (CAD). The association of the APOB gene polymorphism c.12669G>A, p. Gln4154Lys with the risk of CAD varies considerably in different populations. The present study represents the first investigation regarding the role of this APOB gene polymorphism with CAD in the Indian Punjabi population. We have studied the APOB gene polymorphism c.12669G>A, p. Gln4154Lys and its relationship with lipid, apoB, low-density lipoprotein (LDL) heterogeneity and oxidation in subjects suffering from CAD. The study was conducted on 87 patients with CAD; 75 healthy subjects served as controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine the DNA polymorphism in the APOB gene. Frequency of R-(mutant) allele was significantly high (p <0.05) in CAD patients when compared to controls. Variations in serum lipid levels in the R+R+ and R+R- APOB genotypes were insignificant (p >0.05). However, serum apoB levels were significantly raised (p <0.05) in CAD patients with the R+R- genotype as compared to those with the R+R+ APOB genotype. Coronary artery disease patients had raised significantly raised (p <0.01) Log triglyceride/high density lipoprotein-cholesterol (HDL-C) ratio, apoB carbonyl content and increased malondialdehyde-low density lipoprotein (MDA-LDL levels, irrespective of APOB genotype as compared to controls. Carriers of the R- allele are at higher risk of CAD, probably because of elevated serum apoB levels in the Indian Punjabi population. Overall, it may be concluded that the R- allele might be associated with increased susceptibility towards CAD development in the Indian Punjabi population, and one of the linking factor is the elevation in serum apoB levels. However, this association needs further evaluation in a larger population. Secondly, the robust mechanism behind the positive association of the R- allele with raised serum apoB levels needs to be explored, which might be helpful in the strengthening the observed results.
