• Clinical and Experimental Pediatrics
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• v.48 no.3
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• pp.337-341
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• 2005

Thyrotropin receptor(TSHR) mutations must be considered when congenital hyperthyroidism has persisted, but there has been no evidence for autoimmunity. TSHR mutations leading to constitutive activation of the thyroid gland were identified as the molecular cause of autosomal dominant nonautoimmune hyperthyroidism and sporadic congenital hyperthyroidism. We report two cases of hyperthyroidism caused by germline TSHR mutation who presented with exessive sweating and no evidence of autoimmune thyroid disease. They were brothers and their mother had undergone thyroidectomy because of hyperthyroidism. Direct sequencing of the polymerase chain reaction-amplified exon 10 of the TSHR genomic DNA revealed a transition of GCT to GTT, resulting in an exchange of alanine 627 to valine in the patients and their mother. This might be a novel mutation or polymorphism, but we did not perform any functional gene study. But considering the clinical profiles, we can conclude that hyperthyroidism of these two brothers might come from the point mutation described above.

• Annals of Pediatric Endocrinology and Metabolism
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• v.23 no.4
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• pp.235-239
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• 2018

Most cases of congenital hyperthyroidism are autoimmune forms caused by maternal thyroid stimulating antibodies. Nonautoimmune forms of congenital hyperthyroidism caused by activating mutations of the thyrotropin receptor (TSHR) gene are rare. A woman gave birth to a boy during an emergency cesarean section at 33 weeks of gestation due to fetal tachycardia. On the 24th day of life, thyroid function tests were performed due to persistent tachycardia, and hyperthyroidism was confirmed. Auto-antibodies to TSHR, thyroid peroxidase, and thyroglobulin were not found. The patient was treated with propylthiouracil and propranolol, but hyperthyroidism was not well controlled. At 3 months of age, the patient had craniosynostosis and hydrocephalus, and underwent a ventriculoperitoneal shunt operation. Direct sequencing of the TSHR gene showed a heterozygous mutation of c.1899C>A (p.Asp633Glu) in exon 10. No mutations were discovered in any of the parents in a familial genetic study. We have reported a case of sporadic nonautoimmune congenital hyperthyroidism, by a missense mutation of the TSHR gene, for the first time in South Korea.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.576-579
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• 2007

The syndrome of resistance to thyroid hormone (RTH) is characterized by reduced tissue sensitivity to thyroid hormone (TH). In the majority of subjects, RTH is caused by mutations in the thyroid hormone receptor beta ($TR{\beta}$) gene, located on the chromosome locus 3p24.3. RTH is inherited in an autosomal dominant manner. The clinical presentation of RTH is variable, but common features include elevated serum levels of thyroid hormone (TH), a normal or slightly increased thyrotropin (thyroid stimulating hormone, TSH) level that responds to thyrotropin releasing hormone (TRH), and goiter. We report a 4 year-old girl, who was clinically euthyroid in spite of high total and free $T_4$, and $T_3$ concentrations, while TSH was slightly increased. Sequence analysis of the thyroid hormone receptor beta gene (THRB) confirmed a heterozygous C to T change at nucleotide number 1303, resulting in a substitution of histidine by tyrosine at codon 435 (H435Y). Further analysis of her parents revealed that the H435Y variation was a de novo mutation since neither parents had the variation. Her parents' TH and TSH levels were within normal range.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.1
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• pp.101-108
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• 1998

We investigated the effect of ${\alpha}-subunit$ of the stimulatory GTP-binding protein ($G{\alpha}_s$) gene mutation on the expression of the thyrotropin-releasing hormone (TRH) receptor (TRH-R) gene in GH3 cells and in growth hormone (GH)-secreting adenomas of acromegalic patients. In the presence of cyclohexicmide, forskolin and isobutylmethylxanthine, cholera toxin, and GH-releasing hormone (GHRH) decreased rat TRH-R (rTRH-R) gene expression by about 39%, 43.7%, and 46.7%, respectively. Transient expression of a vector expressing mutant-type $G{\alpha}_s$ decreased the rTRH-R gene expression by about 50% at 24 h of transfection, whereas a wild-type $G{\alpha}_s$ expression vector did not. The transcript of human TRH-R (hTRH-R) gene was detected in 6 of 8 (75%) tumors. Three of them (50%) showed the paradoxical GH response to TRH and the other three patients did not show the response. The relative expression of hTRH-R mRNA in the tumors from patients with the paradoxical response of GH to TRH did not differ from that in the tumors from patients without the paradoxical response. Direct PCR sequencing of $G{\alpha}_s$ gene disclosed a mutant allele and a normal allele only at codon 201 in 4 of 8 tumors. The paradoxical response to TRH was observed in 2 of 4 patients without the mutation, and 2 of 4 patients with the mutation. The hTRH-R gene expression of pituitaty adenomsa did not differ between the tumors without the mutation and those with mutation. The present study suggests that the expression of TRH-R gene is not likely to be a main determinant for the paradoxical response of GH to TRH, and that $G{\alpha}_s$ mutation may suppress the gene expression of TRH-R in GH-secreting adenoma. However, a certain predisposing factor(s) may play an important role in determining the expression of TRH-R.