Association study of the -866G/A UCP2 gene promoter polymorphism with type 2 diabetes and obesity in a Tehran population: a case control study.

BACKGROUND A functional polymorphism in the uncoupling protein 2 (UCP2) gene promoter has been associated with obesity and type 2 diabetes (T2D) in some populations. The impact of UCP2 polymorphisms on diabetes and obesity is still under debate. Contradictory results have been reported in different populations world-wide. To clarify the contribution of the UCP2 gene -866 G/A polymorphism in the Iranian population, we studied its association with obesity and T2D. METHODS A total of 225 unrelated subjects were studied: 75 T2D patients without obesity, 75 obese patients without diabetes and 75 control subjects. The UCP2 -866 G/A polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS In the normal Iranian population, GG polymorphism was significantly associated with an increased HDL-C level (P=0.027). G/A polymorphism was not associated with obesity and T2D in our study population, but the odds ratio (OR) between GG and G/A polymorphism was 0.61 with a confidence interval (CI) range of 0.34 - 1.08 in obese patients. Subjects with AA genotypes in all of the studied groups showed a lower body mass index (BMI) than subjects with the GG genotype. CONCLUSION Although the data in our study population is not statistically significant, the A allele in the UCP2 gene promoter seems to be protective against obesity. This may suggest the possibility of UCP2 as a target molecule for studies on the etiology and treatment of obesity.