NOD2 and inflammatory bowel disease: Constitutive NF-κB activation has been found in inflamed colonic tissue of IBD patients.96,97 Furthermore, genetic mutations in NF-κB-stimulating immune receptors, such as NOD2, and NF-κB target genes, such as IL-12 and IL-23, are associated with human IBD.94 Polymorphisms and mutations in the NFKB1 gene, which encodes the IκB-like molecule p105 and its processing product p50, have also been associated with IBD.98–100 These genetic alterations appear to inhibit NFKB1 gene expression or alter the stability and function of the protein products.