The G360t Polymorphism in the APO AIV Gene and its Association with Combined HDL/LDLCholesterol Phenotype: Tehran Lipid and Glucose Study

Identifying genetic polymorphisms as risk factors for complex diseases can facilitate their prevention, diagnosis, and prognosis. The purpose of this study is to assess the association between Apo AIV polymorphism and lipid factors based on high density lipoprotein cholesterol (HDL-C) levels in a population of the Tehran Lipid and Glucose Study (TLGS). Materials and Methods: A total of 181 elderly TLGS subjects with Combined HDLC/low density lipoprotein-Cholesterol (LDL-C) phenotype were investigated. The distributions of a polymorphic site in the apolipoprotein gene APO AIV and its relationship with total cholesterol, LDL-C, HDL-C, and triglycerides were investigated in subjects with LDL-C> 121 mg/dL and HDL-C< 40 mg/dL (case group) and those with LDL-C< 90 mg/dL and HDL-C> 50 (controls). Results: All the variables studied in the case and control groups were statistically different. At the APO AIV locus the G360T polymorphism at codon 360 showed a significant impact on total cholesterol (G: 211±1.16 vs, T: 228±1.20 mg/dL p 0.038) concentration in the case group and on Apo CIII (G: 157±66.9 vs, T: 83.18±17.1 mg/dL p <0001) level in the controls. These associations remained after adjustment for age, sex and smoking (P values: P Chol: 0.028 and P Apo CIII: 0.021). Conclusion: Difference in the apolipoprotein AIV (G360T) polymorphism in the two groups with the combined HDL/LDL-C phenotype indicates that this phenotype can be a selective phenotype for genetic analysis in this field.