Background: Studies that considered polymorphisms within the apolipoprotein B (APOB) gene as risk factors for coronary heart disease (CHD) have reported conflicting results.
Methods: The phenotypic effects of the 3'VNTR polymorphism of the APOB gene on the susceptibility to CHD were investigated in 120 unrelated healthy individuals and 137 CHD patients. The internal structure of APOB gene 3'VNTR alleles was also analyzed by the methods of SspI restriction mapping and DNA sequencing of the allele fragments.
Results: In total, 14 segregating alleles and 32 genotypes of APOB gene 3'VNTR were characterized in the pooled total of 257 subjects. The frequency of 3'VNTR-B alleles [hypervariable element (HVE) > or =38)] in the CHD cases was higher than that of the controls (10.95% vs. 5.00%, p<0.05). 3'VNTR-B allele was dependently related to total cholesterol levels (p<0.05). Compared with SS homozygotes, 3'VNTR-B allele carriers were associated with an increased risk of CHD (OR=2.137, 95% CI=1.055-4.328, p=0.0349). No significant differences in the internal structure and sequences of APOB gene 3'VNTR alleles were found between cases and controls.
Conclusions: APOB gene 3'VNTR polymorphism exerts an impact on lipid metabolism and may contribute to the susceptibility to the development of CHD in Han Chinese.