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

ABSTRACT

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.