MALT1 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome: However, while Malt1-KO mice as well as MALT1 CID patients display impaired T cell activation (3, 22, 38–47), this is not the case for IPEX patients, scurfy mice and mice only lacking Malt1 in Tregs, where there is a failure to control T cell activation due to the absence of Tregs or the reduced functionality of Tregs leading to lymphoproliferation and autoimmunity, resulting in death (36, 49, 63, 65–67, 71).