FOXP3 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome: Over 40% of cases in nonconsanguineous families are due to potassium channel gene mutations (KCNJ11 or ABCC8), whereas in infants born to consanguineous parents, the most common cause (24%) is a homozygous mutation in the EIF2AK3 gene.1 IPEX syndrome (Immune dysregulation, Polyendocrinopathy, X‐linked) is an extremely rare genetic disorder associated with mutations within FOXP3, which codes for a forkhead transcription factor that controls the development and function of CD4 + CD25 + regulatory T cells.