Endocrine and neuropsychological assessment in a child with a novel mutation of thyroid hormone receptor: response to 12-month triiodothyroacetic acid (TRIAC) therapy.
OBJECTIVE: To determine the endocrine, neuropsychological and genetic features of a child with resistance to thyroid hormone (RTH), and his response to long-term triiodothyroacetic acid (TRIAC) therapy. METHODS: Growth, thyroid function, and neuropsychology were assessed at baseline and during 12-month TRIAC therapy. Genetic analysis was performed by PCR and denaturing high performance liquid chromatography. RESULTS: The main clinical finding was the attention deficit-hyperactivity disorder (ADHD). A novel mutation in exon 10 (phenylalanine to isoleucine in codon 455) was found. Long-term TRIAC therapy was effective in the management of the endocrine and neuropsychological manifestations of the syndrome. CONCLUSIONS: ADHD was the only phenotypic manifestation of this novel mutation of thyroid hormone (TH) receptor. TRIAC is an effective and safe drug in the long-term treatment of children with RTH.