Background : Mutations within the NOD2/CARD15 gene have recently been shown to be associated with Crohn's disease.

Aims : To investigate the clinical impact of the three common NOD2/CARD15 mutations in patients with Crohn's disease.

Methods : We investigated the prevalence of the three common NOD2/CARD15 mutations (Arg702Trp, Gly908Arg, 3020insC) in 180 patients with Crohn's disease, 70 patients with ulcerative colitis and 97 controls. In patients with Crohn's disease, prevalence of NOD2/CARD15 mutations were correlated to clinical and demographical parameters.

Results : In Crohn's disease patients, 35.6% carried at least one mutant allele of NOD2/CARD15 mutations compared with 14.3% of patients with ulcerative colitis (P = 0.006) and to 15.5% of controls (P = 0.0001). Genotype phenotype analyses revealed that NOD2/CARD15 mutations determined younger age at disease diagnosis (P = 0.03), ileal disease location (P = 0.01) and ileocecal resections (P = 0.0002). Interestingly, reoperation with resection of the anastomosis was significantly more frequent in patients with NOD2/CARD15 mutations (P = 0.01).

Conclusions : Our investigations support the current hypothesis that NOD2/CARD15 mutations are associated with a phenotype of Crohn's disease with younger age at diagnosis, ileal involvement, ileocecal resections and a high risk of postoperative relapse and reoperation. NOD2/CARD15 mutations might therefore be used to identify high risk patients for relapse prevention strategies.