The diagnosis of hyperprolactinemia is defined when a single measurement of serum PRL is above the upper limit of normal, if there was no excessive venipuncture stress (6) and there are several causes of hyperprolactinemia as physiological (pregnancy and lactation), pharmacological (especially antipsychotic drugs), primary hypothyroidism, renal failure, hepatic insufficiency, pituitary stalk disconnection and pituitary tumors with autonomous prolactin secretion as somatotrophinomas and prolactinomas (7). The gene discussed is PRL; the disease is Primary hypothyroidism.