This variant has been previously described to be causative for IPEX in 2 patients.7 FOXP3 protein expression analysis confirmed decreased FOXP3 expression in T regulatory cells at 25% (normal 55%‐81%) and low normal absolute FOXP3 47 cells/mcL (normal 44‐414). Here, FOXP3 is linked to immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome.