[5] IPEX is caused by mutations in the gene FOXP3, which encodes transcription factor forkhead box P3 (FOXP3).

[4] The classical triad describes the most common symptoms of IPEX: intractable diarrhea, type 1 diabetes, and eczema.

[12] Other symptoms include: thyroid disease, kidney dysfunction, blood disorders, frequent infections, autoimmune hemolytic anemia, and food allergies, among others.

Nevertheless, the first symptoms may present in the first days of life,[15] and some reported cases labeled newborns with intrauterine growth restriction and evidence of meconium in the amniotic fluid.

[6][7] The FOXP3 gene has 12 exons and its full reading open frame encodes 431 amino acids.

FOXP3 expression is characterised by controlling transcription, influencing epigenetic changes and post-transcriptional modifications.

Transcriptional activity is altered through interactions between the N-terminal domain and Eos - which associates with CtBP1 and forms a corepressor complex.

The N‐terminal domain of FOXP3 can also antagonize the transcription factors RORγ and RORα, thereby inhibiting TH17 cell differentiation.

All of these findings verify the importance of FOXP3 in the regulation of transcriptional activity and repression in Treg cells.

[17] Early detection of the disease is crucial because IPEX has a high mortality level if left untreated.

IPEX treatment tends to focus on managing symptoms, reducing autoimmunity, and/or treating secondary conditions.

[11] In 1982, Powel et al. published a case report of a family with 19 males who were affected by an X-linked syndrome with symptoms including polyendocrinopathy and diarrhea.

This leads to a frameshift mutation in FOXP3 gene and the expressed protein is truncated, causing functional deficiency of Treg cells.

[22] Scurfy mice have an enlarged spleen and lymph nodes, squinted red eyes, and scaly or "ruffled" skin.

[18] From 2000 - 2001, multiple studies confirmed that IPEX is the human equivalent of scurfy mice and that the FOXP3 gene is responsible.