The -308 and -238 Polymorphisms of the TNF- α Promoter Gene in Type 2 Diabetes Mellitus

Abstract

BACKGROUND: Recently, two G --> A polymorphisms at positions -308 and -238, in the promoter of the tumor necrosis factor-alpha (TNF-alpha) gene, have been identified. These variants have been linked to estimates of insulin resistance and obesity in different ethnic groups. The objective of the present study was to investigate whether these genetic variants of TNF-alpha were associated with features of the insulin resistance in two study populations comprising type 2 diabetic patients and healthy control subjects. METHODS: We analyzed the polymorphisms of TNF-alpha gene in 198 type 2 diabetes mellitus (DM) patients and 169 healthy control subjects. We used five primers and two separate polymerase chain reaction (PCR) to detect the TNF-alpha polymorphism by the multiplex amplification refractory mutation system (ARMS) technique. RESULTS: No statistically significant difference in the -308A and -238A allele frequencies was found between patients with type 2 DM and normal controls. CONCLUSIONS: Our study does not support a major role of the nucleotide -308 or -238 substitutions of the TNF-alpha gene in the pathogenesis of insulin resistance.