Abstract: Objective To investigate the correlation between single nucleotide polymorphisms (SNPs) on the rs290481 site of TCF7L2 gene and type 2 diabetes mellitus complicated with coronary heart disease(CHD). Methods Peripheral blood DNA was extracted and TCF7L2 gene was amplified by polymerase chain reaction (PCR) and then sequenced in 120 patients with simple type 2 diabetes (T2DM), 120 patients with coronary heart disease (CHD), 120 patients with type 2 diabetes combined with coronary (T2DM+CHD) and 120 healthy controls. Chi-square test was used to analyze the difference of genotype frequency in four groups and binary logistic regression was used to analyze the risk factors of diabetes with coronary heart disease. Results The distribution frequency of AA, AG and GG on TCF7L2 and rs290481 SNP sites from T2DM group were significantly different with the controls, CHD group and T2DM plus CHD group respectively (P＜0.01). The serum level of HbAlc and GLU, was significantly different between AA and AG/GG genotypes (P＜0.05). Logistic regression data demonstrated that history of hypertension, HbAlc, GLU and the rs290481 AG/GG genotype of TCF7L2 were independent risk factors of diabetes mellitus complicated with CHD. Conclusions The polymorphism of TCF7L2 rs290481 gene is associated with the risk of type 2 diabetes complicated with CHD. AG/GG genotype confer a significantly increased risk of type 2 diabetes mellitus with CHD.

Key words: single nucleotide polymorphism, polymerase chain reaction, allele, mutation