TNF-Alpha Gene Polymorphisms in Iranian Azari Turkish Patients with Inflammatory Bowel Diseases

CONTEXT: Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the bowel (IBD) whose causes are not fully known. Emerging data indicate that alterations in cytokine synthesis may play a role in IBD pathogenesis. AIMS: We aimed to determine the association between tumor necrosis factor-alfa (TNFα) promoter polymorphisms (at positions − 308 and − 1031) and susceptibility to IBD among Iranian Azari Turkish patients. SETTINGS AND DESIGN: One hundred and one patients with IBD and 100 healthy subjects were analyzed. MATERIALS AND METHODS: Both polymorphisms in the promoter region of the TNFα gene at positions -1031T/C and -308G/A were detected by polymerase chain reaction-restriction fragment length polymorphism assay. All statistical analyses were calculated with SPSS for Windows 16.0. The Fisher's exact test was used to test for departure from Hardy–Weinberg equilibrium of the genotype frequencies (P > 0.05). RESULTS: The allele frequency of the TNFα-308G and -1031T were higher in IBD patients but did not reach statistical significance. However, the homozygous TT genotype for the SNP-1031 T > C was significantly higher in UC patients than in healthy controls (P = 0.01) and the heterozygous CT genotype for the SNP -1031 T > C was significantly lower in UC patients than in healthy controls (P = 0.03). CONCLUSIONS: The TNFα-1031 T allele confers a significant risk for developing UC in Iranian Azeri Turkish patients. Also the frequency of TNFα-1031 C allele was considerably low among patients with UC and it may have protective role among them (OR = 0.43; P = 0.01).