Moreover, some diseases of immune dysregulation fall in differential diagnosis with IPEX syndrome mainly due to the fact that patients can present severe inflammatory bowel disease and other IPEX-like autoimmune features, but they do not show tTreg cell impairment (mutations in ITCH, TPP2, JAK1, PEPD, IL10, and IL10R) (52, 80). Here, PEPD is linked to inflammatory bowel disease.