ABSTRACT
Objective:To assess clinical and genetic features in a patient with thyroid hormone resistance syndrome(RTH) and explore the pathogenic mechanism.Methods:The clinical data of the proband was collected. The genomic DNA was extracted from peripheral blood samples of the patients. The pathogenic variant was identified using whole-exome sequencing and confirmed by Sanger sequencing. Then the function of the mutation sites was detected by bioinformatics.Results:The patient presented with chest distress, palpitation, and persistent atrial fibrillation, along with elevated levels of serum free triiodothyronine(FT 3), free thyroxine(FT 4), and thyroid stimulating hormone(TSH), which suggested RTH clinically. The genetic analysis identified a heterozygous mutant of THRβ(c.1313G>A) gene at exon 8, which was a missense mutation causing the substitution of arginine to histidine at 438 position of the protein(p.R438H). Its inheritance pattern was unknown. This mutation was considered as a new one that had not been reported. Conclusion:A novel pathogenic THRβ gene mutation was found in the patient with RTH, which might be the cause of this disease. This variant c. 1313G>A is located in the ligand binding domain of THRβ, which might result in low protein activity.