Similarly, a transition “AAUAAA”→“AAUGAA” within the PAS of Foxp3 (forkhead box P3) transcript contributes to the IPEX syndrome (Immunodysregulation, Polyendocrinopathy, and Enteropathy, X-linked), a fatal autoimmune disease by reduced levels of Foxp3 transcription factor leading to the dysfunction of regulatory T cells [8]. The gene discussed is FOXP3; the disease is autoimmune disease.