TREATMENT OF PITUITARY RESISTANCE TO THYROID-HORMONE (PRTH) IN AN 8-YEAR-OLD BOY

We report on an 8-year-old boy with pituitary resistance to thyroid ho rmone (PRTH) having a cysteine for arginine substitution at codon 320 in the TR-beta gene who was presented because of thyrotoxicosis. Due t o its suppressive effect on the pituitary thyrotropin secretion, treat ment with D-thyroxine (D-T4) was started. After a few days, clinical e uthyroidism was achieved but thyroid stimulating hormone secretion was not suppressed. Symptoms of thyrotoxicosis relapsed when therapy was interrupted so that therapy with D-T4 was reinstituted and continued t o date. Symptoms did not recur, and the psychomotor development procee ded normally. D-T4 should therefore be considered in the treatment of thyrotoxicosis in PRTH.