Apolipoprotein E gene polymorphism and total serum cholesterol level in Iranian population
Background: Apolipoprotein E (APOE) is known as a major regulator of blood lipid levels in humans. A number of APOE gene allelic variants have been reported including E2, E3 and E4. Recent studies suggested a role for APOE in obesity and increased Body Mass Index (BMI) and plasma lipid levels in obese children. Aim: The aim of this study was to examine the association between APOE genetic variants and the BMI and lipid profile in an Iranian cohort. Setting and Design: Samples were obtained from subjects who participated in a study based on the WHO-designed MONICA (multinational monitoring of trends and determinants in cardiovascular disease) study for coronary artery disease risk assessment in Zone 17 of Tehran. The study was approved by the local ethical committee. Informed consent was obtained from all subjects included in this study. Materials and Methods: Subjects (n = 320) were recruited. The level of triglyceride (TG) and total serum cholesterol was tested for all subjects in this study. Genotyping for APOE was carried using polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) technique. Statistical Analysis: Levels of significance were determined using contingency tables by either Chi-square or Fisher exact analysis using the STATA (v8) software. The analysis of regression and significance of differences for level of cholesterol and TG was established by one-way analysis of variance followed by Dunnett post hoc multiple comparison tests using SPSS software Version 11.5. Results: The frequency of allele E2 was significantly higher in patients with total serum cholesterol level < 200 mg/dl (P 0.01 OR 2.1 95% CI 1.1-4.2). Conclusion: The association found in this study between allele E2 and lower total cholesterol level had been reported in previous studies. We have also observed that the frequency of genotype E2/E3 and E2/E4 was significantly higher in patients with normal total serum cholesterol level compared to patients with abnormal cholesterol (P = 0.003 OR 2.4 95% CI; 1.3-4.6). Our data needs to be repeated in a larger population with more information for serum LDL and HDL levels and their subgroups.