IPEX (Immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome) is a syndrome caused by a genetic mutation in the FOXP3 gene,[2][3][4] which encodes a major transcription factor of regulatory T cells (Tregs). Such a mutation leads to dysfunctional Tregs and, as a result, autoimmune diseases. The classic clinical manifestations are enteropathy, type I diabetes mellitus and eczema.