FOXP3 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome: Normal percentages of CD4+CD25+FOXP3+ T cells can be detected in the peripheral blood of IPEX 1 patients; however, these mutant FOXP3 Tregs are functionally impaired and are the main pathogenetic cause of the multi-organ autoimmunity in IPEX patients [72].