The SH2 domain-containing inositol-5’-phosphatase 1 (SHIP1), predominantly expressed in hematopoietic tissues [1], is required for the regulation of immune cell compartments, lymphoid and innate immune cell function and intestinal fibrosis [2,3].We and others have shown that SHIP1-/- mice spontaneously develop an intestinal inflammatory phenotype resembling the inflammatory bowel syndrome (IBD) Crohn’s disease (CD), with increased granulocyte infiltration and a profound T cell depletion observed in the small intestine [4,5]. The gene discussed is INPP5D; the disease is Cowden disease.