 The first mutation found to be associated with Crohn's was a frameshift in the NOD2 gene (also known as the CARD15 gene), followed by the discovery of point mutations.Over thirty genes have been associated with Crohn's; a biological function is known for most of them.For example, one association is with mutations in the XBP1 gene, which is involved in the unfolded protein response pathway of the endoplasmic reticulum.