The main molecular mechanism of RTH is a mutation of the thyroid hormone receptor beta (THRB) gene, which encodes the TH receptor β (THRβ).[6] Currently, more than 100 mutational sites have been reported, most of which are located in 3 “hotspot” regions.[4] These carboxyl terminal ligand binding regions of THRβ encoded by exons 7 to 10 in the THRB gene are amino acids 234 to 282, 310 to 353, and 429 to 46.[7,8,9,10]. The gene discussed is THRB; the disease is thyroid hormone resistance syndrome.