Autoimmune Polyglandular Syndrome Type 1 (APS-1) is a rare, inherited disorder that affects the immune system. It is characterized by the presence of two or more autoimmune diseases, such as Addison's disease, hypoparathyroidism, and type 1 diabetes. People with APS-1 may also have other autoimmune diseases, such as vitiligo, alopecia, and pernicious anemia. APS-1 is caused by a mutation in the AIRE gene, which is responsible for regulating the immune system. Treatment for APS-1 typically involves managing the individual autoimmune diseases, as well as taking immunosuppressive medications to reduce the risk of further autoimmune diseases.