Presence of the X+ Allele in Apolipoprotein B Gene Increase the Total Cholesterol and Apolipoprotein B Concentration in Tehranian People

Lipid level variations are among the most important risk factors for cardiovascular disease. Apolipoproteins play a the key role in lipid metabolism. In the present study the association of XbaI apolipoprotein B polymorphisms on lipid variation was examined. A cross-sectional study was conducted on 849 subjects from the Tehran Lipid and Glucose Study population. Blood pressure was measured and the body mass index was calculated. TG, Chol, FBS, HDL-C and its subfractions, Apo B and Apo A1 levels were measured, and LDL-C concentration was calculated. A segment of the apo B gene was amplified by PCR and the polymorphism was revealed by RFLP using XbaI restriction enzyme. Allele frequencies obtained for X+ and X- were 27.6 % and 72.4%, respectively and were in the Hardy-Weinberg Equilibrium (HWE). The presence of the X+ allele was significantly associated with increased total cholesterol (X+X+: 193 ± 1.2 mg/ml vs. X-X-: 182 ± 1.2 mg/ml, P 0.022) and apolipoprotein B (X+X+: 116 ± 1.5 mg/ml vs. X-X-: 104 ± 1.4 mg/ml, P 0.024). The associations were significant even after adjustment for age, sex, BMI, smoking, diastolic and systolic blood pressure and fasting blood sugar. The observed allele frequencies were similar to other studies. Considering the association of XbaI polymorphisms with lipids factors, it is important to examine the relationship of Apo B gene variation and similar gene with lipids metabolisms.