Chronic lymphocytic thyroiditis, also known as Hashimoto’s thyroiditis, is an autoimmune thyroid disease which presents with inflammatory cell infiltration of the thyroid gland and is characterised by the production of autoantibodies to thyroglobulin (anti-TG) and thyroperoxidase (anti-TPO) [79,80]. The gene discussed is TPO; the disease is autoimmune thyroid disease.