The relation between NOD2/CARD15 mutations and the prevalence and phenotypic heterogeneity of Crohn's disease: lessons from the Israeli Arab Crohn's disease cohort.

The prevalence of Crohn's disease depends on geographic location and racial background. Arg702Trp, Gly908Arg, and Leu1007fsinsC mutations in the NOD2/CARD15 gene are associated with Crohn's disease in Caucasians. The mutation rate among Israeli Jewish patients is 27%-41%. The prevalence of Crohn's disease is much lower in the Israeli Arab compared to the Israeli Jewish population. We studied the NOD2/CARD15 mutation rate and disease phenotype (according to the Vienna classification) among the Israeli Arabs and compared them with those in an Israeli Jewish cohort. We recruited 66 Israeli Arab patients and 122 ethnically matched controls. Five patients (8.2%) and three controls (2.3%) carried one NOD2/CARD15 mutation. The phenotypic characteristics of the Arab and Jewish patients were very similar. We conclude that NOD2/CARD15 mutations do not contribute to Crohn's susceptibility in the Israeli Arab population and suggest that NOD2/CARD15 mutations have an important effect on Crohn's prevalence within a specific population but not on the phenotype.