The participation of thyroid hormones in the pathogenesis of depression is evidenced by epidemiologic data that indicate that thyroid dysfunction often leads to the development of mental diseases; among patients with affective disorders, 1–4% have hypothyroidism, and 4–40% present subclinical hypothyroidism (Duntas and Maillis, 2013; Loh et al., 2019). The gene discussed is TG; the disease is major depressive disorder.