Editing Thymus (section)

====Autoimmune polyendocrine syndrome====
[[Autoimmune polyendocrine syndrome type 1]] is a rare genetic autoimmune syndrome that results from a genetic defect of the thymus tissues.{{sfn|Harrison's|2015|pp=2756-7}} Specifically, the disease results from defects in the [[autoimmune regulator]] (AIRE) gene, which stimulates expression of self antigens in the epithelial cells within the medulla of the thymus. Because of defects in this condition, self antigens are not expressed, resulting in T cells that are not conditioned to tolerate tissues of the body, and may treat them as foreign, stimulating an immune response and resulting in autoimmunity.{{sfn|Harrison's|2015|pp=2756-7}}  People with APECED develop an autoimmune disease that affects multiple [[endocrine]] tissues, with the commonly affected organs being [[hypothyroidism]] of the [[thyroid gland]], [[Addison's disease]] of the [[adrenal gland]]s, and [[candida infection]] of body surfaces including the [[oral mucosa|inner lining of the mouth]] and of the [[nail (anatomy)|nail]]s due to dysfunction of [[T helper 17 cell|TH17 cells]], and symptoms often beginning in childhood. Many other autoimmune diseases may also occur.{{sfn|Harrison's|2015|pp=2756-7}} Treatment is directed at the affected organs.{{sfn|Harrison's|2015|pp=2756-7}}