Regulatory T cells from 7 patients had altered function and FOXP3 mutations that resulted in lost or reduced FOXP3 protein expression; 2 infants had reduced regulatory T-cell activity and reduced levels of FOXP3 protein, although we did not detect mutations in FOXP3 coding region, poly-A site, or promoter region (called FOXP3-dependent AIE).
Abnormal FOXP3 expression results in defective regulatory functions of T cells, which in turn cause a systemic T-cell-mediated autoaggressive disorder, now called immune dysregulation, polyendocrinopathy autoimmune enteropathy X-linked syndrome.
Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX; OMIM 304930) syndrome is a congenital syndrome characterized by autoimmune enteropathy, endocrinopathy, dermatitis, and other autoimmune phenomena.