CTLA4 and Autoimmunity: Schmidt syndrome is a polygenic disorder inherited in an autosomal dominant pattern with incomplete penetrance and is linked to the following genes: HLA-DR3, HLA-DR4, CTLA-4, PTPN22 and CD25-IL-2 [5-7].At present, tuberculosis causes only about 7%-20% of Addison’s cases, whereas autoimmune conditions account for the majority, around 70%-90%.