We took advantage of the Scurfy (Sf) mouse model that mimics the IPEX syndrome (immune dysregulation, poly-endocrinopathy, enteropathy, X-linked) responsible in humans for a severe poly-autoimmunity and inflammatory disorder, caused by hemizygous loss-of-function mutations in the X-linked gene FOXP3/FoxP333,34. Here, FOXP3 is linked to Autoimmunity.