Apo B gene haplotype is associated with lipid profile of higher risk for coronary heart disease in Caucasian Brazilian men

We investigated using haplotype analysis whether genetic variation of the a po B gene is associated with a higher risk for coronary heart disease in a Brazilian population. Ins/ Del, Xbal, and EcoRI polymorphic sites of the ap olipoprotein B (apo B) gene were studied in 67 patients with CHD and in 67 age-matched healthy individuals selected from a population of Brazilians. T he allelic frequency of apo B polymorphisms did not differ between the CHD patients and controls. However, a significant linkage disequilibrium was ob served between the Xbal site and Ins/Del polymorphism of the apo B gene in CHD individuals (chi (2), P < 0.01). The simultaneous presence of the rare X+ and Del alleles (X+Del haplotype) in males of CHD group was associated w ith significantly higher serum levels of total cholesterol (P< 0.01), trigl ycerides (P< 0.05), and LDL-cholesterol (P < 0.05), and with a higher TC/HD L-C ratio (P< 0.05). These data indicate that a single haplotype, X+Del, wi thin the apo B gene exerts an impact on lipid metabolism and may contribute to the susceptibility to development of CHD in males from a population of Brazilians. J. Clin. Lab. Anal. 15:19-24, 2001. (C) 2001 Wiley-Liss, Inc.