Development of a CD-like phenotype in SHIP1-/- mice is dependent on hematopoietic cells, as transplantation of SHIP1-/- hematolymphoid cells into wild type mice is sufficient to transfer ileitis and WT bone marrow transplantation cures SHIP1-/- mice of mucosal inflammatory disease in both the lungs and small intestine [4,6]. Here, INPP5D is linked to Cowden disease.