Hemizygous mutations in FOXP3 located on the X chromosome result in IPEX syndrome (immune dysregulation, polyendocrinopathy, enteropathy, X-linked) classically presenting in the first few weeks of life with severe enteropathy, eczema and type 1 diabetes mellitus [18]. The gene discussed is FOXP3; the disease is immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome.