Identification of a de novo mutation (H435Y) in the THRB gene in a Korean patient with resistance to thyroid hormone / 소아과

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 (TRbeta) 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 T4, and T3 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.

A Case of Thyroid Hormone Resistance (RTH) / 대한소아내분비학회지

Thyroid hormone resistance (RTH) is a rare autosomal dominant disease characterized by reduced tissue sensitivity to thyroid hormone. Approximately 90% of subjects with RTH have mutation in the thyroid hormone receptor beta (TRbeta) gene. Approximately 10% of subjects diagnosed as having RTH do not carry mutation in the TRbeta gene. We report a 12-year-old male. The patient was euthyroid in spite of high total and free T4 and T3 concentrations, while TSH is slightly increased. TSH response to TRH stimulation was normal, and TSH values to TRH stimulation after T3 suppression revealed partial response. Sequence analysis of TRbeta gene showed no mutation. We report a case of RTH without mutations in the TRbeta gene.

A Case of Syndrome of Resistance to Thyroid Hormone Associated with Mutation(M313T) in Thyroid Hormone Receptor Beta Gene / 대한내분비학회지

Syndrome of resistance to thyroid hormone(RTH) is inherited by an autosomal dominant trait, and characterized by elevated thyroid hormone levels with reduced responsiveness of the pituitary and peripheral tissues to thyroid hormone action. All of the reported RTH patients have various mutations in the ligand-binding domain coding region of the thyroid hormone receptor beta gene. A 21-year-old man visited our hospital complaining of fatigue. He had mild thyroid goiter and intermittent palpitation. Thyroid function test showed elevated total T3, free T4, and TSH levels. Levels of TSH free a-subunit and basal pituitary hormones, except prolactin, were normal. MRI of the sellar region showed no abnormal finding. TSH response to TRH stimulation was normal, and TSH values to TRH stimulation after T3 suppression revealed partial response. Sequeuce analysis of the thyroid hormone receptor beta gene confirmed a heterozygous missense mutation in exon 9; and the amino acid alteration was a substitution of a threonine(ACG) for a methionine(ATG) at codon313. Sequeuce analysis of the parents showed no mutation.We report the first case of a man with RTH caused by a de novo mutation(M313T) in TRbeta gene, confirmed by sequeuce analysis.