Hashimoto thyroiditis, which is characterized by enlarged thyroid gland, marked intrathyroidal monocyte infiltration, and elevated serum antithyroid autoantibody (ATA) concentrations, including anti-thyroglobulin antibody (Tg-Ab) and anti-thyroid peroxidase antibody (TPO-Ab) [4], is the most frequent underlying factor leading to hypothyroidism [5]. The gene discussed is TPO; the disease is hypothyroidism.