The most prevalent AITDs are Hashimoto’s thyroiditis, which is characterized by high serum levels of antithyroglobulin (A-Tg) and antithyroperoxidase (A-TPO) antibodies and lymphocytic infiltration [2], and Graves’ disease, which involves the production of thyroid autoantibodies directed at specific antigens. The gene discussed is TPO; the disease is Hashimoto thyroiditis.