Our study also showed that neither the genetic factors (deficiency in Eif2ak4 gene with or without abnormal human CEACAM6 expression) nor the microbial factor (AIEC colonization) alone is sufficient to induce a modification in the gut microbiota composition, reinforcing the notion of the multifactorial and complex etiology of CD. The gene discussed is EIF2AK4; the disease is Cowden disease.