In patients with both an idiopathic and acquired organic GH deficit, an increase in T4 to T3 conversion also seems to be the main mechanism of the changes in thyroid hormone levels after the introduction of rhGH therapy, but the disclosure of central hypothyroidism, earlier masked by untreated GHD, has also been reported [22,23,24,26,28,44]. The gene discussed is TG; the disease is Central hypothyroidism.