ATG16L1 and Cowden disease: The Thr300Ala substitution polymorphism within the ATG16L1 gene is associated with an ileal CD phenotype, similar as the CD-associated NOD2 mutations [65, 102] and a specific E. coli strain, adherent-invasive E. coli [103, 104], which are able to survive and to replicate within intestinal macrophages [105].