FOXP3 and Autoimmunity: In humans, mutations in FOXP3 lead to a lack of functional Tregs and results in immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome that manifests as multi-organ autoimmunity, including diabetes, thyroiditis and allergy (i.e., eczema); in the absence of a bone marrow transplantation, death occurs within a year of birth (9–13).