Associations between single-nucleotide polymorphisms of the adiponectin gene, serum adiponectin levels and increased risk of type 2 diabetes mellitus in Iranian obese individuals

Abstract

Introduction: Adiponectin is an adipose tissue-secreted hormone with important metabolic effects. There have been inconsistent reports about SNPs of the adiponectin gene and risk of type 2 diabetes (T2DM). The aim of this study was to investigate any association between SNPs (+45 T/G and +276 G/T) of the adiponectin gene with serum adiponectin levels, metabolic factors and risk of T2DM in obese individuals. Design and methods: Genotyping for two common SNPs of adiponectin gene was performed in 50 unrelated obese type 2 diabetic patients and 52 obese non-diabetic control subjects by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Lipid profile was measured by enzymatic methods. Serum adiponectin, insulin, leptin and glucose levels were measured by immunoassay, and glucose oxidase methods, respectively. Results and conclusion: It was observed that obesity and T2DM are associated with low serum adiponectin levels. The G allele and TG/GG genotype of SNP 45 occurred more frequently than the T allele and TT genotype in T2DM patients compare to the controls (p<0.05). Subjects with the G/G + TG genotype of SNP 45 were at increased risk for T2DM [Odds Ratio (OR) 2.574; 95% Confidence Interval (CI) 1.051–6.302; p=0.036] compared with those T/T genotype. There was no statistically significant difference in allele and genotype frequencies of SNP 276 comparing control group with T2DM group. Thus, our results demonstrated that, adiponectin SNP 45T/G, rather than SNP 276G/T, is more associated with risk of T2DM in obese individuals.