Effects of Ava II and Hinc II polymorphisms at the LDL receptor gene on serum lipid levels of Brazilian individuals with high risk for coronary heartdisease

Coronary heart disease (CHD) has presented high prevalence in the Brazilian population. Nevertheless, studies of genetic risk factors for CHD in our c ountry are insufficiently carried out. We have investigated the effects of Ava II (exon 13) and Hinc II (exon 12) polymorphisms at the low-density lip oprotein receptor (LDLR) gene on circulating lipids of 170 white unrelated individuals presenting a lipid profile with high risk for CHD (HRG) and 130 controls (CG) from Sao Paulo City, Brazil. Ava II and Hinc II polymorphic regions at the LDLR gene were amplified by PCR and analyzed by enzymatic is otyping. The frequency of the genotypes A+A+ (Ava II) and H+H+ (Hinc II) wa s greater in HRG group compared to that of the controls (32 vs. 16% and 32 vs. 18%, respectively). Moreover, in the HRG group, A+A+ and H+H+ genotypes were associated with high concentrations of total cholesterol and LDL-C in serum (P = 0.0001). Our results indicate that Ava II and Hinc II polymorph isms at the LDLR locus contribute to the variability of total cholesterol a nd LDL-C levels in HRG individuals. These data suggest that the LDLR polymo rphism remains a useful genetic marker for predicting CHD risk. J. Clin. La b. Anal. 13:251-258, 1999. (C) 1999 Wiley-Liss, Inc.