XIAP and inflammatory bowel disease: IL10/R, TTC7A and IKBKG are known to cause severe colitis in early infancy (12, 42, 43), whereas XIAP deficiency, IBD with Hermansky–Pudlak Syndrome, and IBD caused by mutation in TNFAIP3 can occur in a wide range of ages from infancy to adulthood (32, 44–46).