Dataset Information

Very Severe Resistance to Thyroid Hormone ? in One of Three Affected Members of a Family with a Novel Mutation in the THRB Gene.

ABSTRACT: A 13-year-old female with a novel THRB gene mutation (c.1033G>T, p.G345C) presented with 3- to 6-fold higher serum iodothyronine levels and more severe clinical manifestation than 2 other family members carrying the same mutation. The leukocytes of the proband expressed both wild-type and mutant THRB mRNAs, excluding the possibility of a partial deletion of the allele not carrying the mutation. The proband's fibroblasts showed reduced responsiveness to triiodothyronine compared with those of another affected family member. The more severe clinical and biochemical phenotype suggest a modifier-mediated worsening of the resistance to thyroid hormone.

SUBMITTER: Fujisawa H

PROVIDER: S-EPMC6797074 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Publications

Very Severe Resistance to Thyroid Hormone β in One of Three Affected Members of a Family with a Novel Mutation in the <i>THRB</i> Gene.

Fujisawa Haruki H Gagné Julie J Dumitrescu Alexandra M AM Refetoff Samuel S

Thyroid : official journal of the American Thyroid Association 20190920 10

A 13-year-old female with a novel <i>THRB</i> gene mutation (c.1033G>T, p.G345C) presented with 3- to 6-fold higher serum iodothyronine levels and more severe clinical manifestation than 2 other family members carrying the same mutation. The leukocytes of the proband expressed both wild-type and mutant THRB mRNAs, excluding the possibility of a partial deletion of the allele not carrying the mutation. The proband's fibroblasts showed reduced responsiveness to triiodothyronine compared with those ...[more]

PMID: 31432759

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Project description:BackgroundThe thyroid hormone receptor α gene (THRA) transcript is alternatively spliced to generate either thyroid hormone receptor (TR)α1 or a non-hormone-binding variant protein, TRα2, the function of which is unknown. Here, we describe the first patients identified with a mutation in THRA that affects both TRα1 and TRα2, and compare them with patients who have resistance to thyroid hormone owing to a mutation affecting only TRα1, to delineate the relative roles of TRα1 and TRα2.MethodsWe did clinical, biochemical, and genetic analyses of an index case and her two sons. We assessed physical and radiological features, thyroid function, physiological and biochemical markers of thyroid hormone action, and THRA sequence.FindingsThe patients presented in childhood with growth failure, developmental delay, and constipation, which improved after treatment with thyroxine, despite normal concentrations of circulating thyroid hormones. They had similar clinical (macrocephaly, broad faces, skin tags, motor dyspraxia, slow speech), biochemical (subnormal ratio of free thyroxine:free tri-iodothyronine [T3], low concentration of total reverse T3, high concentration of creatine kinase, mild anaemia), and radiological (thickened calvarium) features to patients with TRα1-mediated resistance to thyroid hormone, although our patients had a heterozygous mis-sense mutation (Ala263Val) in both TRα1 and TRα2 proteins. The Ala263Val mutant TRα1 inhibited the transcriptional function of normal receptor in a dominant-negative fashion. By contrast, function of Ala263Val mutant TRα2 matched its normal counterpart. In vitro, high concentrations of T3 restored transcriptional activity of Ala263Val mutant TRα1, and reversed the dominant-negative inhibition of its normal counterpart. High concentrations of T3 restored expression of thyroid hormone-responsive target genes in patient-derived blood cells.InterpretationTRα1 seems to be the principal functional product of the THRA gene. Thyroxine treatment alleviates hormone resistance in patients with mutations affecting this gene, possibly ameliorating the phenotype. These findings will help the diagnosis and treatment of other patients with resistance to thyroid hormone resulting from mutations in THRA.FundingWellcome Trust, NIHR Cambridge Biomedical Research Centre, Marie Curie Actions, Foundation for Development of Internal Medicine in Europe.

Dataset Information

Very Severe Resistance to Thyroid Hormone ? in One of Three Affected Members of a Family with a Novel Mutation in the THRB Gene.

Publications

Very Severe Resistance to Thyroid Hormone β in One of Three Affected Members of a Family with a Novel Mutation in the <i>THRB</i> Gene.

Similar Datasets

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