[Influence of genetic combinations on HDL-C levels in a Southern Brazilian population].

BACKGROUND low HDL-C levels are important predictors of coronary disease, the first cause of death worldwide. Many factors affect HDL-C levels, such as polymorphisms of genes encoding for key proteins of the reverse cholesterol transport pathway. OBJECTIVE to investigate the influence of seven polymorphisms of the CETP, APOA1, ABCA1 and SCARB1 genes on HDL-C levels in a southern Brazilian population. METHODS the polymorphisms were investigated in a sample of 500 individuals of European descent, but HDL-C levels from only 360 individuals were adjusted for cofactors using multiple linear regressions in the association study. The sample was divided in tertiles according to adjusted HDL-C levels, and allele and haplotype frequencies were compared between the 1st and 3rd tertiles of adjusted HDL-C levels. RESULTS When combinations of risk alleles were tested, the frequency of allele combinations in three genes (haplotype 1 of APOA1 gene, variant 2S of SCARB1 gene, and allele B1 of CETP gene) was significantly higher in the lower tertile of adjusted HDL-C (28.3%) than in the upper tertile (14.9%; p=0.008), which indicated that the presence of these variants increased 2.26 times the chances of having HDL-C levels below 39.8 mg/dl. CONCLUSION these markers, when studied separately, are expected to have a small influence on the characteristic under analysis, but greater influence was detected when the markers were studied in combination. In a population of southern Brazilians, our data showed a significant influence of variant combinations of APOA1, SCARB1 and CETP genes on HDL-c levels.