Research on THRβ gene mutation in a patient with thyroid hormone resistance syndrome using whole-exome sequencing / 中华内分泌代谢杂志

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.

The establishment of zebrafish Dio3b gene knockout model / 中华内分泌代谢杂志

Objective To set up the model of deiodinase ( Dio) 3b-/- zebrafish and to observe the effect of which on embryo development. Methods The zebrafish model of Dio3b-/- was set up by CRISPR-Cas9 gene editing technology, PCR and sequencing was used to confirm the efficiency of deletion. The heart rate of embryos at 48 hours post fertilization was counted. The locomotor activity of 5-7 days post fertilization larve was detected using behavior tracking system. Results The model of Dio3b knockout zebrafish was set up successfully. The heart rate of embryos Dio3b-/- increased ( P＜0. 001) and the locomotor activity of 5-7 days post fertilization larves lacking Dio3b gene increased (P＜0.05) significantly compared with that of wild type control respectively. Conclusion The deletion of zebrafish Dio3b gene results in the phenotype of hyperthyroidism and the model of Dio3b-/- is proper for studying the effect of partial excess thyroid hormone on embryo development.

DUOX2 mutations are frequently associated with congenital hypothyroidism in a Chinese Patients / 中华内分泌代谢杂志

Objective To investigate the prevalence of DUOX2 mutations in Chinese patients with congenital hypothyroidism (CH) and to discuss the inheritance pattern of DUOX2 gene.Methods Blood samples were collected from 91 CH children and their genomic DNA was extracted from peripheral blood leukocytes.All exons and exon-intron boundaries of DUOX2 were analyzed by target next-generation sequencing and family trios was established to study the inheritance pattern of DUOX2 gene.Results Fifty-four out of 91 children with CH carried DUOX2 mutation, with a prevalence of 59.34%.Of the 54 CH children, 36 carried DUOX2 biallelic mutations.In all 12 family trios with probands carrying biallelic DUOX2 mutations, the parents carried heterozygous DUOX2 mutations while still showing normal thyroid function, suggesting that CH caused by DUOX2 mutations is inherited in an autosomal recessive manner.Conclusion DUOX2 gene is one of the most frequently mutated genes in Chinese CH patients and its inheritance pattern is an autosomal recessive one.