IRGM and Crohn disease: Crohn’s disease patients develop inflammation in Peyer’s patches, and invasion by bacteria, specifically adherent-invasive E. coli (AIEC) pathobiont, may be involved as nod2-/- Knockout (KO) mice show colonization of the pathobiont.14 Other susceptibility genes that trigger Crohn’s disease encode an autophagy-related protein 16–1 (ATG16L1) and an immunity-related GTPase M (IRGM) protein that are components of autophagy pathway (Table 1).