CEDIE   05498
CENTRO DE INVESTIGACIONES ENDOCRINOLOGICAS "DR. CESAR BERGADA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
THYROID HORMONE RESISTANCE (THR) AND AUTOIMMUNE THYROIDITIS
Autor/es:
CHIESA A; MARTINEZ A; VIEITES A; RIVOLTA C; TARGOVNIK H; GRUÑEIRO-PAPENDIECK L
Lugar:
Viña del Mar Chile
Reunión:
Congreso; XVIIII Reunion Anualde la Sociedad latinoamerican ad e Endocrinología Pediátrica (SLEP); 2006
Institución organizadora:
SLEP
Resumen:
THR is a dominantly inherited syndrome of reduced tissue responsiveness to thyroid hormone usually due to mutations in the T3 receptor beta gene. We describe a 17 year old boy that was referred to our department at  4.7 years for short stature. He had a mild subvalvular aortic stenosis  without cardiac insufficiency and celiac disease. He grew along the the 3rd percentile up to age 11 coping well with his gluten free diet. At 14 years of age he started puberty. At 14.5 years he grew poorly ,  (height –2.5 SDS) and a diffuse goiter was noted. Thyroid function was assessed and  TSH levels were 26.7mu/l T4 11ug/dl  with positive anti thyroid antibodies. With diagnosis of autoinmune thyroiditis was treated with l-T4 100ug/day.Growth improved but TSH levels failed to inhibit in spite of high  T4 levels. (TSH 14 mU/l T4 13.5 ug/dl FT4 3.11ng/dl).  At the age of 17 with height at  -1.96 SDS and complete sexual development, treatment was withdrawn and pituitary and peripheral tissue responses to graded doses of triiothyronine (LT3) were studied. 50, 100 and 200ug/m2 /day of LT3 inhibited basal TSH to 3 , 2 and  0.70mU/ml respectively. TRH /TSH test was still respondent under the higher dose and SHBG showed a paradoxical decrease. The patient became clinically hypothyroid. Molecular studies found a missense mutation in exon 9 of the TRb gene ( pN331D) .  Treatment with l-thyroxine was reinitiated with clinical improvement but TSH remained high. TRIAC was added to treatment. THR has to be considered in patients with high TSH and thyroid hormones levels even in the occurrence of autoimmune disorders.