Etiology of Crohn's disease: many roads lead to autophagy.

Crohn's disease is a complex multifactor diseases that occur in individuals with genetic predisposition in whom environmental and microbial triggers cause a deleterious chronic immune response. Susceptibility to Crohn's disease is influenced by common variants at many loci. Genetic studies have emphasized the role of host susceptibility in inflammatory bowel disease onset with the identification of about 100 risk loci, most of which encode proteins involved in immunity, host defense against microbes, and gut homeostasis. In this review, we focus on susceptibility genes related to autophagy in the etiology of Crohn's disease (CD) and their complex interplay with the gut microbiota, as illustrated by the relationship between immunity-related GTPase family M alleles, microRNA, and xenophagy in CD predisposition.