Association of TNF-α -857 Polymorphism with Inflammatory Bowel Disease in a Group of Iranian Azeri Individuals

BACKGROUND Inflammatory bowel disease (IBD) is a chronic, relapsing, inflammatory disorder of the gastrointestinal tract that includes two entities, Crohn's disease (CD) and ulcerative colitis (UC). As with other complex diseases, both genetic susceptibility and environmental factors play role in the pathogenesis of these diseases. The tumor necrosis factor α (TNF-α) gene is located in the IBD3 region on chromosome 6p21 which is a good functional candidate for involvement in susceptibility to IBD. In addition, the promoter region of TNF-α contains various polymorphisms that have shown a significant association with IBD. METHODS In this case control study we investigated the TNF-α -857 polymorphism in 109 patients (89 UC and 16 CD) who suffered from IBD and 100 healthy age, sex and ethnicity matched adults selected from the same population, as the control group. The polymorphism was checked by amplification refractory system (ARMS) and polymerase chain reaction (PCR). RESULTS Investigation of the association of TNF-α -857 gene promoter polymorphism with both types of IBD showed no significant difference in genotype and allele frequencies of this polymorphism between UC patients and controls. However, a possible association of TNF-α -857 polymorphism (p=0.03) was identified with CD. CONCLUSION TNF-α -857 polymorphism may have a role in the development of CD in the Iranian Azeri Turkish population.