Iodine, as a component of thyroid hormones, represents 65% and 58% of the weight of thyroxine (T4) and triiodothyronine (T3), respectively; therefore, iodine status is directly associated with thyroid function, expressing a “U”-shaped relationship between iodine intake and the risk of thyroid diseases, e.g., an insufficient intake is associated with goiter, hypothyroidism, cretinism, adverse obstetric outcomes, and growth and intellectual development disorders, inter alia (iodine deficiency disorders—IDDs) [6,7,8]. This evidence concerns the gene TG and hypothyroidism.