Relationships Between The Functional Polymorphism In The Promoter Of Uncoupling Protein 2 Gene And Obesity And Type 2 Diabetes

Objective To investigate the association between the common -866G/A polymorphism in the promoter of the human uncoupling protein-2 (UCP2) gene and obesity and type 2 diabetes and insulin sensitivity/secretion in Tianjin Han population. Methods Genomic DNA was isolated from peripheral blood according to standard procedures. By means of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, the genotypes of the common -866G/A polymorphism in the UCP2 gene were determined in 440 unrelated Chinese (including 162 subjects with normal glucose tolerance and 278 type 2 diabetics). Results No significant difference (P=0.245) of genotype frequencies of the common -866G/A polymorphism in the UCP2 gene was observed between normal glucose tolerance subjects (G/G 0.228, G/A 0.481 and A/A 0.290) and type 2 diabetics (G/G 0.288 G/A 0.482 and A/A 0.230). The common -866G/A polymorphism is not associated with type 2 diabetes in obese subjects. All the observed genotype frequencies were in Hardy-Weinberg equilibrium. Glucose-stimulated insulin secretion estimated by several indexs of β-cell function was significantly lower in carriers of the -866A/A genotype compared with -866G/A or -866G/G genotype in type 2 diabetic patients. Conclusion The common -866G/A polymorphism in the UCP2 gene is correlated with the glucose stimulated insulin secretion (GSIS) from islet β-cell in type 2 diabetic Chinese. It is suggested the common -866G/A polymorphism in the UCP2 gene may contribute to the dysfunction of insulin secretion in the pathogenesis of type 2 diabetes mellitus in Chinese. UCP2 promoter -866G/A polymorphism does not affect obesity in Chinese type 2 diabetic patients. Higher A allele frequency in the Tianjin Han population...