Interleukin-6 (IL-6)-597 A/G (rs1800797) & -174 G/C (rs1800795) gene polymorphisms in type 2 diabetes

BACKGROUND & OBJECTIVES: Diabetes is a metabolic pro-inflammatory disorder characterized by chronic hyperglycaemia and increased levels of circulating cytokines suggesting a causal role for inflammation in its aetiology. In order to decipher the role of interleukin-6 (IL-6) in type 2 diabetes mellitus (T2DM) we analyzed two promoter polymorphisms -597 A/G (rs1800797) and -174 G/C (rs1800795) in T2DM cases from north India, and in healthy controls. METHODS: DNA was isolated from venous blood samples of T2DM patients (n=213) and normal healthy controls (n=145). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed after biochemical analysis. The genotypic and allelic frequency distributions were analyzed. RESULTS: The clinical/biochemical parameters of T2DM cases when compared to controls showed a significant difference. No significant association was observed with -597A/G polymorphism while, -174 G/C showed a highly significant association (P<0.001). In haplotypic analysis, combination of -597G*/-174C* showed significant association (P=0.010). INTERPRETATION & CONCLUSIONS: Our data suggest that IL-6 gene polymorphisms play a prominent role in T2DM disease susceptibility in population from north India.