However, since NOD2 and ATG16L1 mutations, which are closely related with bacterial handling, are observed in western CD population [5], and although not the same mutation, ATG16L2 mutation related with regulation of bacteria-related signal was observed in Korean CD patients [9], it can be presumed that intestinal microbiota play an important role in the development of CD [21]. The gene discussed is ATG16L1; the disease is Cowden disease.