Moreover, deletion or loss-of-function mutations of NOD2 in particular are associated with gut microbiota dysbiosis, invasion of pathobionts and inflammatory bowel disease (IBD) (Caruso et al., 2014; Philpott et al., 2014), which suggests that NOD2 is important for sensing peptidoglycan in the gut and priming innate immune pathways to maintain intestinal barrier function and preventing microbiota- and pathogen-induced inflammation (Al Nabhani et al., 2017; Caruso et al., 2014; Philpott et al., 2014). This evidence concerns the gene NOD2 and inflammatory bowel disease.