A mutation in thyroid hormone receptor beta causing resistance to thyroid hormone in a neonate

Abstract

Resistance to thyroid hormone (RTH) is an inherited syndrome characterized by reduced tissue responsiveness to thyroid hormones. The main defects are due to mutations in thyroid hormone receptor beta (TRbeta). A male, term neonate was admitted because of indirect hyperbilirubinemia and polycythemia. Physical examination revealed ophtalmopathy. High serum T-4 with unsupressed thyroid stimulating hormone (TSH) levels suggested RTH. In this presented case, A317T mutation was detected on exon 9 of the TR beta-1 gene and precise diagnosis had been confirmed with genetic testing. In neonates and infants exhibiting hypo or hyperthyroidism features with increased circulating levels of thyroid hormones with a normal or increased serum TSH concentration should raise the suspicion of RTH.