As previously shown by many groups, including ours, IL-15 not only enhances the cytotoxicity of CD8+ intraepithelial lymphocytes (IELs) and NK cells in CeD but also impairs the functions of T regulatory (Treg) cells [13,14], suggesting that such cytokines promote the dysregulation of immune mechanisms that contribute to the immunopathogenesis of the disease. The gene discussed is IL15; the disease is cranioectodermal dysplasia.