RARE DISEASE
Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta
Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta
Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta
Synonyms: RTHb, Resistance to thyroid hormone beta, Resistance to thyroid hormone due to a mutation in TRb
Synonyms: RTHb, Resistance to thyroid hormone beta, Resistance to thyroid hormone due to a mutation in TRb
Synonyms: RTHb, Resistance to thyroid hormone beta, Resistance to thyroid hormone due to a mutation in TRb
Drug discovery
2
drugs
With orphan designations
Overview
Resistance to thyroid hormone beta (RTHβ) is a rare autosomal dominant disorder caused by THRB gene mutations, leading to impaired tissue responsiveness to thyroid hormones (TH). Characterized by elevated free T4/T3 with non-suppressed TSH, patients may present as clinically euthyroid or with variable hypo-/hyperthyroid symptoms. Diagnosis requires genetic testing after excluding TSH-secreting pituitary adenomas and assay interference. Phenotypic variability stems from differential mutant TRβ expression across tissues [1][2][5][10].
Burden
Recurrent goiter (common), cardiovascular risks (tachycardia), and neurocognitive impairments (ADHD, "foggy brain") [1][6][14].
High rates of misdiagnosis leading to unnecessary interventions [9][14].
Lifetime monitoring required due to evolving symptoms and comorbidities (e.g., autoimmune thyroid disease) [1][11][17].
Categories: rare endocrine diseases, rare genetic diseases
Research Papers
102 drug discovery papers about Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta, with 4 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
102 drug discovery papers about Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta, with 4 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-04-18 | The human THRB thyroid hormone receptor gene and the puzzle of retinal disease phenotypes.
The THRB thyroid hormone receptor gene has attracted growing attention for its role in retinal development and disease. This gene has particularly critical roles in cone photoreceptors, the specialized cells that mediate color vision and high acuity vision. THRB controls the diversity of cone types that are required for color vision and influences cone survival in mammalian model species and human retinal organoid cultures. This central role of THRB in the cone life history prompts an expectation of equally critical roles in the human retina in vivo. Puzzlingly, overt retinal phenotypes have gone unnoticed for most known human THRB mutations. However, upon closer inspection, retinal impairment is now increasingly recognized. Mutations in 3'-exons of THRB (encoding the receptor ligand-binding domain) are known in resistance to thyroid hormone, typically a dominant syndrome with endocrine and other impairments but generally without mention of retinal disorders. However, a few specific investigations have revealed variable, usually moderate cone impairment. Recently, non-syndromic macular dystrophy cases have been found with sequence variants in a THRB 5'-exon encoding the N-terminus of one of the receptor isoforms expressed by the gene, suggesting a surprisingly wider involvement in retinal disease. We discuss this intriguing receptor gene and its emerging role in human retinal disorders.
2026-02-25 | Iopanoic acid rapidly restores euthyroidism in refractory thyrotoxicosis pre-thyroidectomy: a retrospective study.
Restoration of euthyroidism in patients with thyrotoxicosis prior to thyroidectomy is recommended to decrease perioperative morbidity and thyroid storm risk. This is challenging when conventional anti-thyroid medication is contraindicated or ineffective. Iopanoic acid (IOPA), an iodinated contrast medium formerly used as an oral cholecystographic agent, may facilitate treatment of thyrotoxicosis, but limited manufacture precludes its use in the UK. We investigated the effectiveness and safety of IOPA for optimizing thyroid status in treatment-resistant thyrotoxicosis prior to thyroidectomy at a referral centre. With prior permission of our Drug and Therapeutics Committee, we sourced laboratory-grade (>98% pure) IOPA and administered this orally to control ongoing, severe thyrotoxicosis prior to thyroidectomy in 12 patients with inadequate response to standard therapies. Underlying aetiologies included Graves' disease, amiodarone-induced thyrotoxicosis, toxic multinodular goitre and resistance to thyroid hormone beta. Medical case notes were reviewed retrospectively to analyse clinical and biochemical outcomes. All patients exhibited a decline and normalization/near-normalization of free T3 (FT3) levels (mean 55% decrease, SEM 4.5%), with minimal changes in FT4 levels. Eleven patients proceeded to uneventful thyroidectomy, and IOPA was well tolerated with no directly attributable side effects. IOPA is a safe and effective agent for controlling biochemical thyrotoxicosis in preparation for thyroidectomy, including disease refractory to conventional medication. Highly pure, laboratory-grade iopanoic acid that is approved for human use is now available in the UK; consideration should be given to more widespread use for emergency treatment of life-threatening hyperthyroidism.
2026-02-06 | Identification of a novel THRB mutation causing thyroid hormone resistance syndrome.
Resistance to thyroid hormone syndrome (RTHS) is a rare disorder caused by mutations in the thyroid hormone receptor beta (THRB) gene, resulting in impaired action of thyroid hormones on target tissues and organs. We report a case of a 57-year-old Chinese male who presented with palpitations and hand tremors. Laboratory tests revealed elevated serum thyroid hormone levels, while serum thyroid-stimulating hormone (TSH) levels remained within the normal range. Enhanced magnetic resonance imaging of the pituitary gland showed no abnormalities. Through genetic testing, we identified a rare heterozygous point mutation in the THRB gene, specifically c.938T>C: p.M313T. To the best of our knowledge, this mutation site has not been previously reported in the literature. Clinically, RTHS is often misdiagnosed as hyperthyroidism, leading to inappropriate treatment and potential exacerbation of thyroid hormone resistance. Therefore, accurate diagnosis of this condition is crucial. Given the rarity of RTHS, we hope that this case report will enhance the understanding of its clinical manifestations and management, particularly in patients with THRB gene mutations.
2026-01-01 | The Role of Transdermal 3,5-Diiodo-L-Thyronine (T2) in Hypothyroid Metabolic Recovery: A Formulation Rationale and Consumer Case Series
Weight loss resistance remains one of the most prevalent and clinically frustrating complaints among hypothyroid patients, persisting in a substantial proportion of individuals despite normalization of serum thyroid-stimulating hormone (TSH) on levothyroxine (T4) monotherapy. Conventional thyroid hormone replacement corrects circulating thyroxine deficits but fails to address the downstream mitochondrial metabolic impairment that underlies depressed basal metabolic rate (BMR) in these patients. 3,5-Diiodo-L-thyronine (T2), once considered a biologically inert byproduct of thyroid hormone deiodination, has emerged in the past two decades as a potent, rapid-acting stimulator of mitochondrial respiration with a distinct mechanism of action from its parent hormones T4 and triiodothyronine (T3). T2 exerts its metabolic effects primarily through direct, non-genomic activation of cytochrome c oxidase (Complex IV) and upregulation of mitochondrial uncoupling proteins (UCPs), resulting in increased lipid oxidation and thermogenesis without proportional activation of nuclear thyroid hormone receptors (TR-alpha and TR-beta). This receptor selectivity profile confers a meaningful clinical advantage: T2 stimulates basal metabolic rate while exhibiting substantially lower potential for cardiac overstimulation and TSH suppression compared with T3. Transdermal delivery of T2 bypasses hepatic first-pass metabolism and gastrointestinal degradation, offering pharmacokinetic advantages including sustained systemic release and more consistent steady-state serum concentrations. This white paper presents the formulation rationale for a transdermal 3,5-Diiodo-L-thyronine product, including the biophysical mechanism of action, pharmacokinetic basis for transdermal delivery, clinical application framework, and an observational consumer case series detailing outcomes in weight-loss-resistant hypothyroid individuals utilizing the formulation in real-world settings.
2025-12-27 | Thyroid hormone resistance syndrome: Diagnostic and therapeutic challenges
Thyroid hormone resistance syndrome (THRS) is a rare genetic disorder caused by mutations in the thyroid hormone receptor beta (THRB) gene. It is characterized by an unusual combination of elevated levels of thyroid-stimulating hormone and thyroid hormones. The primary symptom of THRS is goiter. The clinical presentation is diverse, with the same patient exhibiting both symptoms of thyrotoxicosis and hypothyroidism. Even patients with the same mutation in the thyroid hormone receptor gene within the same family demonstrate completely different clinical pictures. All this creates difficulties in choosing a therapy. A peculiarity of the treatment of THRS is the administration of high-dose thyroid hormone preparations in combination with beta-blockers. The use of thyrostatic drugs, thyroidectomy, and radioiodine therapy should be avoided. This article aims to raise awareness among physicians about this disease.
small molecules
2026-04-18 | The human THRB thyroid hormone receptor gene and the puzzle of retinal disease phenotypes.
The THRB thyroid hormone receptor gene has attracted growing attention for its role in retinal development and disease. This gene has particularly critical roles in cone photoreceptors, the specialized cells that mediate color vision and high acuity vision. THRB controls the diversity of cone types that are required for color vision and influences cone survival in mammalian model species and human retinal organoid cultures. This central role of THRB in the cone life history prompts an expectation of equally critical roles in the human retina in vivo. Puzzlingly, overt retinal phenotypes have gone unnoticed for most known human THRB mutations. However, upon closer inspection, retinal impairment is now increasingly recognized. Mutations in 3'-exons of THRB (encoding the receptor ligand-binding domain) are known in resistance to thyroid hormone, typically a dominant syndrome with endocrine and other impairments but generally without mention of retinal disorders. However, a few specific investigations have revealed variable, usually moderate cone impairment. Recently, non-syndromic macular dystrophy cases have been found with sequence variants in a THRB 5'-exon encoding the N-terminus of one of the receptor isoforms expressed by the gene, suggesting a surprisingly wider involvement in retinal disease. We discuss this intriguing receptor gene and its emerging role in human retinal disorders.
2026-02-25 | Iopanoic acid rapidly restores euthyroidism in refractory thyrotoxicosis pre-thyroidectomy: a retrospective study.
Restoration of euthyroidism in patients with thyrotoxicosis prior to thyroidectomy is recommended to decrease perioperative morbidity and thyroid storm risk. This is challenging when conventional anti-thyroid medication is contraindicated or ineffective. Iopanoic acid (IOPA), an iodinated contrast medium formerly used as an oral cholecystographic agent, may facilitate treatment of thyrotoxicosis, but limited manufacture precludes its use in the UK. We investigated the effectiveness and safety of IOPA for optimizing thyroid status in treatment-resistant thyrotoxicosis prior to thyroidectomy at a referral centre. With prior permission of our Drug and Therapeutics Committee, we sourced laboratory-grade (>98% pure) IOPA and administered this orally to control ongoing, severe thyrotoxicosis prior to thyroidectomy in 12 patients with inadequate response to standard therapies. Underlying aetiologies included Graves' disease, amiodarone-induced thyrotoxicosis, toxic multinodular goitre and resistance to thyroid hormone beta. Medical case notes were reviewed retrospectively to analyse clinical and biochemical outcomes. All patients exhibited a decline and normalization/near-normalization of free T3 (FT3) levels (mean 55% decrease, SEM 4.5%), with minimal changes in FT4 levels. Eleven patients proceeded to uneventful thyroidectomy, and IOPA was well tolerated with no directly attributable side effects. IOPA is a safe and effective agent for controlling biochemical thyrotoxicosis in preparation for thyroidectomy, including disease refractory to conventional medication. Highly pure, laboratory-grade iopanoic acid that is approved for human use is now available in the UK; consideration should be given to more widespread use for emergency treatment of life-threatening hyperthyroidism.
2026-02-06 | Identification of a novel THRB mutation causing thyroid hormone resistance syndrome.
Resistance to thyroid hormone syndrome (RTHS) is a rare disorder caused by mutations in the thyroid hormone receptor beta (THRB) gene, resulting in impaired action of thyroid hormones on target tissues and organs. We report a case of a 57-year-old Chinese male who presented with palpitations and hand tremors. Laboratory tests revealed elevated serum thyroid hormone levels, while serum thyroid-stimulating hormone (TSH) levels remained within the normal range. Enhanced magnetic resonance imaging of the pituitary gland showed no abnormalities. Through genetic testing, we identified a rare heterozygous point mutation in the THRB gene, specifically c.938T>C: p.M313T. To the best of our knowledge, this mutation site has not been previously reported in the literature. Clinically, RTHS is often misdiagnosed as hyperthyroidism, leading to inappropriate treatment and potential exacerbation of thyroid hormone resistance. Therefore, accurate diagnosis of this condition is crucial. Given the rarity of RTHS, we hope that this case report will enhance the understanding of its clinical manifestations and management, particularly in patients with THRB gene mutations.
2026-01-01 | The Role of Transdermal 3,5-Diiodo-L-Thyronine (T2) in Hypothyroid Metabolic Recovery: A Formulation Rationale and Consumer Case Series
Weight loss resistance remains one of the most prevalent and clinically frustrating complaints among hypothyroid patients, persisting in a substantial proportion of individuals despite normalization of serum thyroid-stimulating hormone (TSH) on levothyroxine (T4) monotherapy. Conventional thyroid hormone replacement corrects circulating thyroxine deficits but fails to address the downstream mitochondrial metabolic impairment that underlies depressed basal metabolic rate (BMR) in these patients. 3,5-Diiodo-L-thyronine (T2), once considered a biologically inert byproduct of thyroid hormone deiodination, has emerged in the past two decades as a potent, rapid-acting stimulator of mitochondrial respiration with a distinct mechanism of action from its parent hormones T4 and triiodothyronine (T3). T2 exerts its metabolic effects primarily through direct, non-genomic activation of cytochrome c oxidase (Complex IV) and upregulation of mitochondrial uncoupling proteins (UCPs), resulting in increased lipid oxidation and thermogenesis without proportional activation of nuclear thyroid hormone receptors (TR-alpha and TR-beta). This receptor selectivity profile confers a meaningful clinical advantage: T2 stimulates basal metabolic rate while exhibiting substantially lower potential for cardiac overstimulation and TSH suppression compared with T3. Transdermal delivery of T2 bypasses hepatic first-pass metabolism and gastrointestinal degradation, offering pharmacokinetic advantages including sustained systemic release and more consistent steady-state serum concentrations. This white paper presents the formulation rationale for a transdermal 3,5-Diiodo-L-thyronine product, including the biophysical mechanism of action, pharmacokinetic basis for transdermal delivery, clinical application framework, and an observational consumer case series detailing outcomes in weight-loss-resistant hypothyroid individuals utilizing the formulation in real-world settings.
2025-12-27 | Thyroid hormone resistance syndrome: Diagnostic and therapeutic challenges
Thyroid hormone resistance syndrome (THRS) is a rare genetic disorder caused by mutations in the thyroid hormone receptor beta (THRB) gene. It is characterized by an unusual combination of elevated levels of thyroid-stimulating hormone and thyroid hormones. The primary symptom of THRS is goiter. The clinical presentation is diverse, with the same patient exhibiting both symptoms of thyrotoxicosis and hypothyroidism. Even patients with the same mutation in the thyroid hormone receptor gene within the same family demonstrate completely different clinical pictures. All this creates difficulties in choosing a therapy. A peculiarity of the treatment of THRS is the administration of high-dose thyroid hormone preparations in combination with beta-blockers. The use of thyrostatic drugs, thyroidectomy, and radioiodine therapy should be avoided. This article aims to raise awareness among physicians about this disease.
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Drug Discovery Landscape
2 orphan drug designations for Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta.
2 orphan drug designations for Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
Tiratricol | small molecules | EMA | — | Rare Thyroid Therapeutics International AB |
tiratricol | small molecules | FDA | — | Rare Thyroid Therapeutics International AB |
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