The role of FAS gene variants in inflammatory bowel disease

The analysis of genes thought to be important in inflammatory bowel disease (IBD) has shown that more than half of IBD-related genes are also associated with other autoimmune diseases. The aim of this study was to detect a possible association between the polymorphisms of the (-670 A/G, -1377 G/A) fFas cell surface death receptor (FAS) gene promoter and susceptibility to IBD in the Turkish population.

In total, 125 patients with IBD, including 73 ulcerative colitis and 52 Crohn's disease and also 101 healthy controls without any pathological signs of IBD were considered for the study. Real-time polymerase chain reaction technique was used to detect FAS polymorphisms in this study.

The analysis of FAS -670 A/G polymorphism indicated that the frequency of GG genotype was significantly increased in patients compared with controls (p<0.001). Additionally, AG genotype (p<0.001) and A allele (p<0.001) frequencies were higher in controls than in patients. The analysis of FAS -1377 G/A polymorphism revealed that the frequency of AA genotype was meaningfully increased in patients compared with controls (p<0.001). Additionally, GG genotype (p<0.001) and G allele (p<0.001) frequencies were increased in controls when compared with patients.

FAS -670A/G GG genotype seemed to be a protective allele against IBD; however, AA genotype and A allele were associated with elevated risk of IBD. In the FAS -1377G/A polymorphism, frequencies of the G allele and GG genotype were observed to be protective against IBD, whereas AA, GA genotypes, and A allele frequency increased in the patient group.