The frequency of three common mutations of CARD15/NOD2 gene in Iranian IBD patients

CARD15/NOD2 gene, located on the pericentromeric region of chromosome 16 (IBD 1) has been reported to have an association with IBD, especially Crohn’s disease (CD). Many independent studies have shown a variable association between three common mutations of CARD15, with Crohn’s disease in different ethnic groups. Thus, raising the hypothesis that genetic andor allelic heterogeneity may influence the relationship between CARD15 and Crohn’s disease. In the present study, we have investigated the frequency of three main mutations of CARD15 gene (Arg 702 Trp, Gly 908 Arg and Leu 1007 fsinsC) in Iranian IBD patients and compared it with healthy control population. For this case-control study, 100 ulcerative colitis (UC), 40 Crohn’s disease patients and 100 sex-, age- and ethnicity-matched controls were enrolled from a teaching hospital during a one year period (2003-2004). All three mutations were assessed on DNA of leukocyte cells, by PCR (Polymerase Chain Reaction) and RFLP (Restriction Fragment Length Polymorphism) methods. The mean age of UC, CD and healthy controls were 38.6±14.3, 36.6±14.1, and 38.6±14.2 years. Among the three evaluated CARD15 gene mutations, the frequency of Arg702Trp mutation was significantly higher in Iranian patients with Crohn’s disease (OR19.2 95%CI:4.2–87.3, p<0.001). None of these mutations were associated with ulcerative colitis. This study showed that Arg702Trp mutation of CARD15 gene is probably associated with Crohn’s disease in Iranian population indicating that genetic polymorphisms may differ between populations.