This article provides a thorough examination of immune dysregulation, polyendocrinopathy, enteropathy, and X-linked (IPEX) syndrome, addressing both clinical and molecular components of the condition. The IPEX syndrome is a rare immunological disease in humans caused by inheritable mutations in the FOXP3 gene, the main transcriptional regulator of CD4+ regulatory T (Treg) cell formation and activity. Forkhead box protein 3 (FOXP3+) Treg cells are a distinct T-cell lineage that is important for immunological homeostasis and tolerance to self and nonself antigens. Evidence suggests that the severe, multiorgan autoimmune illness IPEX is caused by a Treg developmental deficit or malfunction.

An in-depth structural and functional study of the molecular domains of FOXP3 is required to gain a better understanding of the clinical heterogeneity and prognosis found in IPEX.