We also focused on the children with very early onset IBD (VEO-IBD), including infantile and toddler onset IBD, as infantile IBD might be partially linked to monogenic diseases such as defects in IL-10 or its receptors, Wiskott-Aldrich Syndrome, XIAP deficiency, leukocyte adhesion deficiencies, CD40L deficiency, IPEX syndrome and several others [7–9]. Here, XIAP is linked to inflammatory bowel disease.