These disorders can be classified into three categories: Treg developmental defects due to FOXP3 deficiency, as seen in immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) and BACH2 deficiency; Treg stability defects related to impaired IL-2 signaling (involving CD25 and CD122); and Treg functional defects (such as CTLA-4 HI, LRBA, DEF6, and STAT3 GOF). Here, CTLA4 is linked to Abnormal intestine morphology.