Forkhead box protein 3 (FOXP3) is a critical transcription factor for CD4+ Foxp3+ Tregs and pathogenic variants in FOXP3 leads to immunodysregulation, polyendocrinopathy, enteropathy X-linked (IPEX) syndrome and prototype of a group of disorders called PIRD (Primary Immune Regulatory Disorders) (40, 41). Here, FOXP3 is linked to polyendocrinopathy.