FOXP3 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome: Bennet et al., in 2001, also reported that patients with the IPEX syndrome (immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome) carried mutations in the FoxP3, which led to dysfunctional FoxP3 protein expression and patients not developing functional Tregs, leading to lymphoproliferative and autoimmune disease [28].