Various thyroid abnormalities, including a low response of serum TSH to a thyrotropin-releasing hormone (TRH) stimulation test [143,144], impaired production of thyroxine (T4) by the thyroid gland [102] and lower free triiodothyronine (fT3) serum levels [145], mainly in KS adults, but also in KS children, were described. Here, TRH is linked to thyroid gland disorder.