At the same time, the number of cells counted by other Treg surface markers (e.g., CD4( +), CD25( +), and CD127(low)) may no longer reflect fully functional Tregs [1, 10, 21, 22] which are highly variable in individuals with IPEX syndrome [23]. This evidence concerns the gene IL7R and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome.