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AIMS: Tumor necrosis factor [alpha] (TNF[alpha]) plays a key role in orchestrating the complex events involved in inflammation and immunity. Accordingly, TNF [alpha] has been implicated in a wide range of autoimmune and infectious diseases, but also in conditions such as obesity and insulin resistance. The aim of the present study was to investigate the association between the -863C/A polymorphism in the promoter of the TNF[alpha] gene and type 2 diabetes in the Tunisian population. METHODS: The polymorphism -863C/A in the TNF[alpha] gene was determined in 211 type 2 diabetes patients and 345 healthy controls using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis. RESULTS: A significant difference in genotype distribution and allele frequency was observed between patients and controls. Patients with type 2 diabetes had significantly higher frequency of the CA+AA genotypes compared to controls [35.5% vs. 22.3%; OR (95%CI), 1.91 (1.31-2.8); p=0.001]. The type 2 diabetes patient group showed a significant higher frequency of the A allele compared to the controls (0.19 vs. 0.11; p=0.001). After adjustment by a stepwise logistic regression method, hypertension, dyslipidemia, and CA+AA genotype were found to be significantly associated with T2D. CONCLUSION: The present study showed a significant and independent association between the -863C/A polymorphism of the TNF[alpha] gene and type 2 diabetes in the Tunisian population. [ABSTRACT FROM AUTHOR]

Background & objectives: The impact of several environmental and genetic factors on diabetes is well documented. Though the association between the vitamin D receptor (VDR) gene polymorphisms and type 2 diabetes mellitus (T2DM) has been analyzed in different ethnic groups, the results have been inconsistent. The aim of this study was to evaluate the possible association between VDR FokI polymorphism and genetic susceptibility to T2DM in Tunisian population. Methods: A total of 439 unrelated patients with T2DM and 302 healthy controls were included in the study. Genomic DNA was extracted from blood and genotyped for the single nucleotide polymorphism (SNP) of FokI (T/C: (rs2228570) by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Results: The genotype distribution and the relative allelic frequencies for the FokI polymorphism were not significantly different between T2DM and controls: in T2DM patients the frequencies of the CC, CT, and TT genotypes were 52.6, 41.0, and 6.1 per cent, respectively, and in controls the genotype frequencies were 55.6, 38.7, and 5.6 per cent, respectively. In our study, the TT genotype of the FokI polymorphism was not associated with T2DM (OR =1.19, 95% CI 0.63 - 2.25, P=0.577). Interpretation & conclusions: Our study showed no significant association of the FokI polymorphism in the vitamin D receptor gene with type 2 diabetes mellitus in Tunisian population. [ABSTRACT FROM AUTHOR]