Tumor Necrosis Factor-Alpha Gene Promoter −308G/A and −238G/A Polymorphisms in Mexican Patients with Type 2 Diabetes Mellitus

The association between some Tumor necrosis factor-alpha (TNF-α) promoter polymorphisms and Type 2 diabetes mellitus (T2DM) remains controversial. Ethnic differences may play a role in these conflicting results. The aim of this study was to investigate the association between −308G/A and −238G/A polymorphisms located in the promoter region of the TNF-α gene and T2DM in Mexican mestizo patients. Nine hundred four individuals (259 patients with T2DM and 645 controls) were genotyped for the −308G/A and −238G/A polymorphisms by PCR—RFLP. We found that the −238A allele increased the risk of developing T2DM in Mexican patients (OR = 1.57, 95% CI: 1.07–2.29; p = 0.018). Moreover, we found that the frequency of the GA haplotype (created by the −308G and −238A alleles) was significantly increased in patients with T2DM when compared with controls (OR = 1.56, 95% CI: 1.05–2.31; p = 0.026). Our results suggest that the −238G/A polymorphism and a specific haplotype (GA) are genetic risk factors for the development of T2DM in Mexican population.