Defects in intestinal epithelial barrier function can be involved in VEO-IBD processes, including loss-of-function mutations in ADAM17 resulting in ADAM17 deficiency (65), IKBKG (encoding NEMO) mutation producing X-linked ectodermal dysplasia and immunodeficiency (59), and COL7A1 mutation causing dystrophic epidermolysis bullos (57). Here, IKBKG is linked to inflammatory bowel disease.