In humans, the recognition of immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) as an autoimmune disorder arising due to FOXP3 mutations, solidified FOXP3 as the key transcription factor in Tregs (7, 8). This evidence concerns the gene FOXP3 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome.