Abstract
Thyroid hormone resistance syndrome is a rare disease in which the level of thyroid hormone is elevated and the level of thyroid stimulating hormone is not suppressed. Mutations in the thyroid hormone receptor β (THRβ) gene are thought to be the primary cause of pathogenesis. In the present study, a Chinese boy of 4 years and 8 months, who had been pre‑diagnosed with resistance to thyroid hormone, was assessed for mutations. The clinical features and thyroid function of the proband and his parents were collected and gene mutations were analyzed using DNA sequencing. Gene sequencing showed that the THRβ genes in the parents of the proband were consistent with the standard sequence, however, in the proband there was a mutation in the tenth exon of the THRβ gene (c. 824 T>C). This is a newly identified mutation site and, to the best of our knowledge, there have been no previous reports of this mutation site. Therefore, it is hypothesized that this mutation is the cause of the pathology in the proband.