Generalized Resistance to Thyroid Hormone

Mendelian MONDO:0009043 Pathograph 14 Show in embeddings browser thyroid hormone resistance syndrome hyperthyroidism

Generalized resistance to thyroid hormone (MONDO:0009043) is the classic, autosomal dominant form of resistance to thyroid hormone beta (RTH-beta), caused by dominant-negative mutations in the thyroid hormone receptor beta (THRB) gene. It produces a paradoxical biochemical signature — elevated circulating free T4 and/or free T3 together with a non-suppressed (normal or inappropriately elevated) TSH — because the pituitary thyrotroph itself is hormone-resistant and fails to shut off TSH secretion despite high circulating hormone. The mutant receptor's mutations cluster in the ligand-binding domain: it retains its DNA-binding and heterodimerization functions but fails to release corepressor and recruit coactivators normally triggered by T3 binding, so it silences T3-target genes even in the presence of the co-expressed wild-type receptor. RTH-beta is further described by three overlapping clinical categories depending on which tissues manifest resistance — "generalized" (pituitary and peripheral tissues both resistant, the category MONDO:0009043 models), "pituitary" (hyperthyroid-range biochemistry with inappropriate TSH secretion), and "peripheral" (hypothyroid-range signs despite normal TSH) — though in practice the clinical spectrum is a continuum rather than three discrete entities, even among relatives sharing the same THRB mutation. This is the pathophysiological mirror image of thyroid hormone *deficiency* (see the `hypothyroidism_thyroid_hormone_deficiency` module and `Congenital_Hypothyroidism`): here, circulating hormone is normal-to-high but target tissues cannot use it, rather than hormone being insufficiently produced.

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1
Mappings
7
Pathophys.
4
Phenotypes
14
Pathograph
1
Genes
3
Medical Actions
1
Subtypes
1
Differentials
2
Trials
1
References
1
Deep Research
🔗

Mappings

MONDO
MONDO:0009043 generalized resistance to thyroid hormone
skos:exactMatch
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Subtypes

1
RTH-beta (THRB dominant-negative) MONDO:0008569
THRB hgnc:11799 HUGO Gene Nomenclature Committee (hgnc) Relation: this subtype is caused by variation in this gene This subtype is caused by variation in THRB (hgnc:11799). hgnc:11799 is a gene from the HUGO Gene Nomenclature Committee. Autosomal dominant inheritance MONDO MONDO:0008569
The classic and commonest form of generalized RTH (roughly 85% of cases), caused by heterozygous dominant-negative missense mutations in THRB that cluster in three hot-spot regions of the ligand-binding domain bordering the T3-binding pocket. The mutant TRβ retains DNA binding and RXR heterodimerization but binds T3 poorly and fails to release the NCoR/SMRT corepressor complex, so it continues to repress T3-target genes and dominantly inhibits the co-expressed wild-type receptor. Clinically heterogeneous, ranging from goiter and tachycardia (relative peripheral thyrotoxicosis in TRα-dominant tissues) to attention and learning difficulties, with biochemically elevated free T4/free T3 and a non-suppressed TSH.
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Pathophysiology

7
THRB Dominant-Negative Receptor Formation
Heterozygous missense mutations in THRB cluster in three hot-spot regions of the ligand-binding domain that border the T3-binding pocket. The mutant TRβ protein retains its DNA-binding domain and its capacity to heterodimerize with RXR at thyroid hormone response elements, but its hormone-binding pocket is distorted, so it binds T3 with markedly reduced affinity.
Genetic context allele_type: missense functional_impact_category: DOMINANT_NEGATIVE
Thyroid hormone receptor (TRβ) DNA/RXR-binding activity GO:0004879 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves Thyroid hormone receptor (TRβ) DNA/RXR-binding activity, annotated with nuclear receptor activity (GO:0004879). GO:0004879 is a molecular function from the Gene Ontology.
Downstream
Impaired Corepressor Release at Thyroid Hormone Response Elements
Show evidence (1 reference)
PMID:15988389 SUPPORT Other
"these three clusters of mutations border the T3-binding pocket"
Localizes the RTH-beta mutation hot spots to the T3-binding pocket of the ligand-binding domain, consistent with a receptor that keeps its DNA-binding/dimerization function but loses normal hormone binding.
Impaired Corepressor Release at Thyroid Hormone Response Elements
Because the mutant receptor cannot undergo the normal T3-induced conformational change, it fails to release the nuclear receptor corepressor complex (NCoR/SMRT) that is bound in the unliganded state, and correspondingly fails to recruit coactivators. The mutant receptor continues to occupy DNA at thyroid hormone response elements, so the corepressor block is not a loss of binding but a persistence of the repressive complex despite the presence of circulating hormone.
Persistent NCoR/SMRT corepressor binding by mutant TRβ GO:0001222 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves Persistent NCoR/SMRT corepressor binding by mutant TRβ, annotated with transcription corepressor binding (GO:0001222). GO:0001222 is a molecular function from the Gene Ontology.
Downstream
Dominant-Negative Inhibition of Wild-Type Receptor Transcription
Show evidence (2 references)
PMID:15988389 SUPPORT Other
"most TRB mutations impair the hormone binding to the receptor and interfere with the mechanism(s) of corepressor release and the consequent recruitment of coactivators"
Directly states the corepressor-release failure and coactivator recruitment failure that follow from impaired T3 binding.
PMID:9647743 SUPPORT In Vitro
"association of corepressor with the RTH mutants through the hinge region is crucial for their dominant negative activity"
Cell-transfection evidence that continued corepressor association (rather than loss of DNA binding or RXR dimerization, which were unaffected) is the molecular requirement for dominant-negative activity.
Dominant-Negative Inhibition of Wild-Type Receptor Transcription
Because the mutant receptor still dimerizes with RXR and binds DNA normally, it competes with the co-expressed wild-type TRβ (and TRα) for response-element occupancy and RXR partnering. The persistent corepressor complex it carries therefore silences T3-target gene transcription genome-wide, not only at alleles it occupies alone — the defining dominant-negative mechanism that distinguishes RTH-beta from a simple loss-of-function receptor null.
Dominant-negative suppression of thyroid hormone receptor signaling GO:0002156 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves Dominant-negative suppression of thyroid hormone receptor signaling, annotated with negative regulation of thyroid hormone receptor signaling pathway (GO:0002156), qualified as gain of function. GO:0002156 is a biological process from the Gene Ontology. ⇑ GAIN OF FUNCTION
Downstream
Pituitary Thyrotroph Resistance to Feedback
Tissue-Selective Peripheral Resistance
Show evidence (1 reference)
PMID:15988389 SUPPORT Other
"The lack of interaction with coactivators appears to be an additional mechanism for the dominant negative effects of mutant TRB on the transcriptional activity of the normal receptor."
States explicitly that the mutant receptor suppresses transcriptional activity driven by the co-expressed normal (wild-type) receptor, the hallmark of a dominant-negative rather than simple loss-of-function mechanism.
Pituitary Thyrotroph Resistance to Feedback
Pituitary thyrotrophs predominantly express TRβ2. Dominant-negative inhibition of TRβ2-mediated transcription blunts the thyrotroph's ability to sense elevated circulating hormone, so the normal negative-feedback suppression of TSH secretion is lost even as free T4/T3 rise.
Pituitary thyrotroph CL:0000476 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves Pituitary thyrotroph, annotated with thyrotroph (CL:0000476). CL:0000476 is a cell type from the Cell Ontology.
Downstream
Elevated Thyroid Hormone with Non-Suppressed TSH
Show evidence (1 reference)
PMID:33176840 SUPPORT Other
"inappropriate secretion of thyroid-stimulating hormone (TSH, normal or elevated)."
Documents the inappropriate (non-suppressed) TSH secretion that follows from thyrotroph resistance to the negative feedback signal.
Tissue-Selective Peripheral Resistance
Peripheral tissues vary in their relative TRα/TRβ expression, so the same circulating hormone excess produces a mixed clinical picture: TRβ-rich tissues (liver, pituitary) show blunted responsiveness (contributing to goiter from continued TSH drive), while TRα-predominant tissues (heart, bone) remain relatively hormone-responsive and show signs consistent with the elevated circulating hormone (tachycardia), producing the clinically heterogeneous, tissue-selective phenotype characteristic of RTH-beta.
Downstream
Elevated Thyroid Hormone with Non-Suppressed TSH
Show evidence (1 reference)
PMID:31588528 SUPPORT Other
"The phenotypic manifestations of RTHβ and RTHα are to some extent correlated with the degree of disruption and the tissue distribution of the TRs being characterized by variable coexistence of hypothyroid or thyrotoxic manifestations in RTHβ"
Directly attributes the mixed hypothyroid/thyrotoxic clinical picture of RTH-beta to differential tissue distribution of TRα versus TRβ.
Elevated Thyroid Hormone with Non-Suppressed TSH
The net systemic result of thyrotroph resistance and continued TSH drive on an otherwise intact thyroid gland is the paradoxical biochemical signature that defines generalized RTH: elevated circulating free T4 and/or free T3 together with a measurable, non-suppressed TSH — a combination that in a gland with normal feedback would instead produce thyrotoxicosis with suppressed TSH.
Downstream
Tissue-Selective Mixed Hypothyroid/Thyrotoxic Phenotype
Show evidence (1 reference)
PMID:31588528 SUPPORT Other
"characterized by elevated circulating levels of T4 and T3 with measurable serum TSH concentrations"
States the defining paradoxical biochemical signature of generalized RTH directly.
Tissue-Selective Mixed Hypothyroid/Thyrotoxic Phenotype
Clinically, patients present with a heterogeneous mixture of features: goiter and attention/learning difficulties (relative hormone insensitivity in TRβ-predominant tissues) alongside resting tachycardia (relative hormone excess acting through relatively intact TRα in cardiac tissue). Severity and the balance of hypothyroid versus thyrotoxic features vary between and even within families carrying the same THRB mutation.
Downstream
Goiter
Resting Tachycardia
Attention Deficit Hyperactivity Disorder
Thyroid Nodules
Show evidence (1 reference)
PMID:33176840 SUPPORT Other
"Clinical manifestations of RTH-β vary from hyperthyroidism to hypothyroidism or simple goiter, and RTH-β is often misdiagnosed clinically."
Documents the clinically heterogeneous, tissue-selective phenotype spanning apparent hyperthyroid and hypothyroid presentations.
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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Generalized Resistance to Thyroid Hormone Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
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Phenotypes

4
Cardiovascular 1
Resting Tachycardia HP:0001649 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Tachycardia (HP:0001649). HP:0001649 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:33176840 SUPPORT Other
"other symptoms include sinus tachycardia"
Directly names sinus tachycardia as a reported RTH-beta symptom.
PMID:33868182 SUPPORT Other
"producing sinus tachycardia in the heart expressing mainly the WT TRα and goiter by TSH stimulation, as the pituitary expresses mainly TRβ including the mutant form"
Explains the mechanistic basis of tachycardia as relatively intact TRα-mediated cardiac responsiveness to the elevated circulating hormone.
Endocrine 1
Goiter FREQUENT HP:0000853 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Goiter (HP:0000853). HP:0000853 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:33176840 SUPPORT Other
"About 65–95% of the RTH-β patients have goiter"
Directly states the frequency of goiter in RTH-beta patients.
PMID:33868182 SUPPORT Other
"Goiter is frequently observed in individuals with RTHβ but is usually of little consequence."
Independent confirmation that goiter is a frequent clinical finding in RTH-beta.
Nervous System 1
Attention Deficit Hyperactivity Disorder FREQUENT HP:0007018 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Attention deficit hyperactivity disorder (HP:0007018). HP:0007018 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:33868182 SUPPORT Other
"Attention deficit disorder (ADHD), reported in 48-83% of individuals with RTHβ, is treated using conventional drugs."
Directly states the reported frequency of ADHD in RTH-beta and names the finding explicitly, rather than a generic disease definition.
Other 1
Thyroid Nodules HP:0025388 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Thyroid nodule (HP:0025388). HP:0025388 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:33868182 SUPPORT Other
"Thyroid nodules are quite prevalent in the general population and thus may occasionally co-exist with RTHβ. Although the majority of thyroid nodules are benign and do not require surgical management, there are few reported cases of papillary thyroid carcinoma in patients with RTHβ."
Documents thyroid nodules, including rare papillary carcinoma cases, as a recognized co-occurring finding in RTH-beta.
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Genetic Associations

1
THRB
Gene: THRB hgnc:11799 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is THRB (hgnc:11799). hgnc:11799 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: CAUSATIVE
Show evidence (3 references)
PMID:15988389 SUPPORT Other
"About 85% of patients with RTH are harboring mutations in thyroid hormone receptor beta (TRB)."
Quantifies THRB as the causal gene in the large majority of RTH-beta cases.
PMID:33868182 SUPPORT Other
"236 different mutations in 805 families have been identified. They are located in the functional areas of the ligand (T3)-binding domain and adjacent hinge region."
Quantifies the mutation spectrum and confirms the ligand-binding-domain and hinge-region clustering already modeled in the pathophysiology chain.
PMID:33868182 SUPPORT Other
"The inheritance of RTHβ is typically autosomal dominant. This is explained by the formation of dimers between the mutant and normal (wild-type; WT) TH receptor (TR) interfering with the function of the WT TRβ."
States the dominant-negative dimerization mechanism underlying autosomal dominant inheritance, directly supporting the genetic_context.functional_impact_category: DOMINANT_NEGATIVE modeling used on the corresponding pathophysiology node.
💊

Medical Actions

3
TRIAC (Triiodothyroacetic Acid) Therapy for RTH-beta
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: tiratricol CHEBI:40021 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses tiratricol (CHEBI:40021). CHEBI:40021 is a therapeutic agent from Chemical Entities of Biological Interest.
TRIAC is a thyromimetic that binds thyroid hormone receptors with high affinity but is not well measured by standard T4/T3 assays; it acts on the mutant/wild-type receptor pool to relieve pituitary and peripheral hyperthyroid-range signaling while lowering circulating T4/T3, without exacerbating hormone resistance in already-resistant tissues.
Mechanism Target:
MODULATES Tissue-Selective Peripheral Resistance — TRIAC acts as a thyroid hormone receptor agonist to relieve hyperthyroid-range symptoms driven by relatively hormone-responsive tissues while lowering circulating free T4/T3 and resting energy expenditure, without worsening resistance in already hormone-resistant tissues (e.g., liver).
Show evidence (1 reference)
PMID:41131705 SUPPORT Human Clinical
"TRIAC therapy in RTHβ relieves hyperthyroid symptoms and lowers resting energy expenditure and circulating thyroid hormones without worsening hepatic hormone resistance or exacerbating cardiac thyromimetic activity."
Direct clinical-trial evidence for the mechanism and effect of TRIAC therapy on the tissue-selective resistance/thyrotoxicosis balance in RTH-beta.
Show evidence (2 references)
PMID:41131705 SUPPORT Human Clinical
"The treatment of resistance to thyroid hormone β (RTHβ) is challenging because features of hyperthyroidism in some tissues coexist with a hormone-resistant, hypothyroid state in other organs."
Frames why RTH-beta cannot be treated with conventional antithyroid/levothyroxine approaches and motivates the receptor-selective TRIAC strategy.
PMID:41131705 SUPPORT Human Clinical
"nadir FT4 concentrations fell to within the reference interval in all but 1 patient"
Confirms TRIAC normalized free T4 into the reference interval in nearly all treated patients, not merely a partial reduction.
Beta-Adrenergic Blockade (Atenolol) for RTH-beta Tachycardia
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: atenolol CHEBI:2904 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses atenolol (CHEBI:2904). CHEBI:2904 is a therapeutic agent from Chemical Entities of Biological Interest.
Selective beta-blockade with atenolol is used to control the resting tachycardia produced by relatively intact TRα-mediated cardiac responsiveness to the elevated circulating hormone. Atenolol is preferred over non-selective agents because it does not inhibit peripheral T4-to-T3 conversion, avoiding a further rise in T3.
Mechanism Target:
MODULATES Resting Tachycardia — Beta-adrenergic blockade symptomatically controls the tachycardia arising from relatively hormone-responsive cardiac TRα signaling, without correcting the underlying receptor defect.
Show evidence (1 reference)
PMID:33176840 SUPPORT Other
"Selective beta-blockers can be considered for patients with obvious tachycardia during resting. Because atenolol cannot inhibit the conversion of T4 to T3, it is the best choice for RTH-β with tachycardia."
Directly recommends atenolol specifically (over non-selective beta-blockers) for RTH-beta tachycardia and states the rationale.
Show evidence (1 reference)
PMID:33868182 SUPPORT Other
"beta blockade may be employed to help with tachycardia"
Independent confirmation of beta-blockade as symptomatic tachycardia management.
Supraphysiologic Intermittent Liothyronine (L-T3) and Avoidance of Ablative Therapy
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: liothyronine (L-T3) CHEBI:18258 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses liothyronine (L-T3), annotated with 3,3',5-triiodo-L-thyronine (CHEBI:18258). CHEBI:18258 is a therapeutic agent from Chemical Entities of Biological Interest.
Because thyroidectomy and radioactive iodine reduce the intact wild-type receptor's compensatory hormone supply and leave persistently elevated TSH driving pituitary hyperplasia and recurrent goiter, ablative therapy is generally avoided in RTH-beta. Instead, supraphysiologic doses of liothyronine (L-T3) given intermittently (e.g., every other day) achieve a brief high peak that suppresses TSH and shrinks goiter, or improves ADHD/cognitive symptoms, without sustaining thyrotoxic hormone levels long enough to cause thyrotoxic side effects.
Mechanism Target:
MODULATES Pituitary Thyrotroph Resistance to Feedback — A brief supraphysiologic L-T3 peak given intermittently suppresses TSH below the level needed to drive thyroid growth, without sustaining elevated hormone long enough to produce thyrotoxic symptoms.
Show evidence (1 reference)
PMID:33868182 SUPPORT Other
"An approach of administering supraphysiologic doses of T3 every other day"
States the intermittent supraphysiologic L-T3 dosing strategy used to suppress TSH and shrink goiter without inducing thyrotoxic symptoms.
Show evidence (2 references)
PMID:33176840 SUPPORT Other
"radioactive iodine and surgical treatment are not recommended because they may lead to pituitary hyperplasia"
States directly that ablative therapy is not recommended in RTH-beta and names the specific complication (pituitary hyperplasia) it risks.
PMID:33868182 SUPPORT Other
"Caution should be exercised in the reduction of TH levels with antithyroid medication and ablative therapies (radioactive iodine or surgery) as it leads to difficulty in the subsequent treatment of hypothyroidism."
Independent confirmation of the avoid-ablative-therapy guidance and its rationale (subsequent hypothyroidism management difficulty).
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Biochemical Markers

3
Serum Free Thyroxine (Free T4) (INCREASED)
Reference Ranges
Thyroxine (T4) free [Moles/volume] in Serum or Plasma 10.0–25.0 pmol/L (Adults; conventional clinical laboratory interval, assay- and age-dependent.)
Elevated free T4 typical of untreated RTH-beta (25.0– pmol/L) → Increased circulating free T4 concentration
Elevated free T4 typical of untreated RTH-beta: Elevated free T4 alongside a non-suppressed TSH (rather than the suppressed TSH expected with primary hyperthyroidism) should prompt consideration of RTH-beta and THRB sequencing.
This interval is a conventional adult clinical laboratory range with no single citable primary source, so it is recorded here rather than attributed to a fabricated citation. The RTH-beta-specific anchor that IS sourced is the pretreatment cohort mean of 30 pmol/L.
Show evidence (1 reference)
PMID:41131705 SUPPORT Human Clinical
"normalized circulating free T4 (baseline free T4 30 pmol/L vs posttreatment 17 pmol/L; P = .007)"
Marked PARTIAL because it reports the pretreatment RTH-beta cohort mean (30 pmol/L, elevated above the conventional adult interval) rather than the reference interval itself; also documents that TRIAC normalized this value.
Serum Thyroid-Stimulating Hormone (TSH) (NORMAL)
Reference Ranges
Thyrotropin [Units/volume] in Serum or Plasma 0.4–4.0 mU/L (Adults; conventional clinical laboratory interval, assay-dependent.)
Non-suppressed (inappropriately normal) TSH despite elevated thyroid hormone (0.4–4.0 mU/L) → Inappropriately normal thyroid-stimulating hormone level
Non-suppressed (inappropriately normal) TSH despite elevated thyroid hormone: A TSH within, or only mildly above, the standard reference interval is abnormal in the specific context of a concurrently elevated free T4/T3 — it should be suppressed in that setting, and its failure to suppress is the defining paradox of generalized RTH-beta.
This interval is a conventional adult clinical laboratory range with no single citable primary source and is recorded here rather than attributed to a fabricated citation. The RTH-beta-specific anchor that IS sourced is the pretreatment cohort mean TSH of 2.1 mU/L, which is squarely within this interval despite the concurrently elevated free T4.
Show evidence (1 reference)
PMID:41131705 SUPPORT Human Clinical
"without any rise in their serum TSH (baseline 2.1 mU/L vs posttreatment 1.7 mU/L; P = .65)"
Marked PARTIAL because it reports the pretreatment cohort mean TSH (2.1 mU/L) rather than the reference interval itself; documents a normal-range TSH coexisting with an elevated free T4 (30 pmol/L) in the same untreated RTH-beta cohort, the paradoxical non-suppressed-TSH signature.
Show evidence (1 reference)
PMID:33176840 SUPPORT Other
"inappropriate secretion of thyroid-stimulating hormone (TSH, normal or elevated)."
States directly that TSH secretion is inappropriate (not suppressed) in RTH-beta despite the concurrent free hormone elevation.
Serum Free Triiodothyronine (Free T3) (INCREASED)
Reference Ranges
– pmol/L (Adults; conventional clinical laboratory interval, assay-dependent.)
Elevated free T3 typical of untreated RTH-beta (– pmol/L) → Increased circulating free T3
Elevated free T3 typical of untreated RTH-beta: Elevated free T3 alongside elevated free T4 and a non-suppressed TSH is the characteristic RTH-beta biochemical triad.
No single citable primary source states a numeric normal interval for this analyte in this cohort, so only the qualitative interpretation band is recorded (no lower_bound/upper_bound), grounded in the RTH-beta biochemical-triad evidence below rather than a fabricated numeric range.
Show evidence (1 reference)
PMID:33176840 SUPPORT Other
"increased serum levels of free triiodothyronine (FT3) and/or free thyroxine (FT4)"
Directly documents the elevated FT3/FT4 biochemical signature of RTH-beta.
🔬

Diagnosis

2
THRB Genetic Testing
Sequencing THRB, focused on the ligand-binding domain and hinge region where mutations cluster.
genetic testing NCIT:C15709 NCI Thesaurus (NCIT)
Results: Identification of a THRB mutation confirms the diagnosis, though roughly 14% of individuals with the classic RTH-beta phenotype have no identifiable THRB mutation (mosaicism or regulatory-region variants have been proposed to explain some of these cases).
Show evidence (2 references)
PMID:33176840 SUPPORT Other
"Genetic diagnosis is the gold standard for RTH-β currently"
States genetic testing as the diagnostic gold standard for RTH-beta.
PMID:33868182 SUPPORT Other
"In 14% of individuals manifesting the RTHβ phenotype no THRB mutations were identified."
Quantifies the fraction of clinically diagnosed cases with no identifiable THRB mutation.
Serum TSH Determination
Measuring serum TSH alongside free T4/T3 is the most sensitive biochemical test to detect reduced sensitivity to thyroid hormone; other peripheral markers of TH action (cholesterol, creatine kinase, alkaline phosphatase, osteocalcin, SHBG) are less reliable unless measured before and after T3 administration.
serum TSH measurement NCIT:C74742 NCI Thesaurus (NCIT)
Results: A non-suppressed (measurable, normal, or elevated) TSH in the presence of elevated free T4/T3 supports RTH-beta over primary hyperthyroidism.
Show evidence (1 reference)
PMID:33868182 SUPPORT Other
"Serum TSH determination remains the most sensitive test to determine reduced sensitivity to TH."
States TSH determination as the most sensitive test directly.
📊

Prevalence

1
Live births (pooled newborn TSH/T4 screening surveys)
Birth Prevalence 2.5–5.26 per 100,000 1–9 per 100,000
Two newborn screening surveys (80,884 and 74,992 infants) identified 2 and 4 THRB mutation carriers respectively, giving prevalence estimates of 1 in 40,000 and 1 in 19,000 live births.
Show evidence (1 reference)
PMID:33868182 SUPPORT Human Clinical
"Surveys of 80,884 and 74,992 newborns using TSH and T4 measurements identified 2 and 4 infants with THRB gene mutations indicating a prevalence of 1 in 40,000 and 1 in 19,000 live births respectively"
Reports the two newborn-screening-based prevalence estimates directly.
🔀

Differential Diagnoses

1

Conditions with similar clinical presentations that must be differentiated from Generalized Resistance to Thyroid Hormone:

TSH-Secreting Pituitary Adenoma (TSHoma) Not Yet Curated MONDO:0019611
Overlapping Features The principal condition to exclude, particularly when there is no family history: TSHoma also produces elevated free thyroid hormone with a non-suppressed TSH. Testing first-degree relatives for the biochemical phenotype is a cost-effective way to support RTH-beta over TSHoma, since incidental pituitary lesions are found in up to 24% of RTH-beta patients, complicating imaging-based differentiation.
Distinguishing Features
  • Failure to suppress TSH after supraphysiologic T3 administration
  • Failure to normally stimulate TSH with TRH
  • Elevated serum SHBG
  • Increased pituitary alpha-glycoprotein/TSH molar ratio
  • Frequent co-secretion of growth hormone or prolactin, with an imaging-confirmed pituitary mass
Show evidence (1 reference)
PMID:33868182 SUPPORT Other
"Characteristics of a TSH-oma include failure to suppress TSH after the administration of supra-physiologic doses of T3, failure to normally stimulate TSH with TSH releasing hormone (TRH)"
Directly states the biochemical dynamic-testing features that distinguish TSHoma from RTH-beta.
🔬

Clinical Trials

2
NCT06307990 NOT_APPLICABLE RECRUITING
Observational study (ADAM-THAD) characterizing the neurological and cardiological phenotype of RTH-beta and RTH-alpha patients, aiming to define frequency, accelerate diagnosis, and develop monitoring tools; also generates patient-derived iPSCs to study molecular mechanisms.
Show evidence (1 reference)
clinicaltrials:NCT06307990 SUPPORT Other
"The goal of this observational study is to learn about the neurological and cardiological phenotype of patients with resistance to thyroid hormone (RTH) syndromes beta and alpha (RTHß and RTHa) due to dominant negative variants in the genes encoding the thyroid hormone receptors alpha (THRA) and..."
Confirms this recruiting observational study's direct relevance to RTH-beta natural history and diagnosis; it also enrolls RTH-alpha patients, which is out of this entry's MONDO:0009043 scope but does not change the RTH-beta relevance.
NCT00001159 NOT_APPLICABLE RECRUITING
NIH Clinical Center natural-history platform for thyroid function disorders broadly, explicitly including thyroid hormone resistance and TSH-secreting pituitary adenomas (the key differential diagnosis).
Show evidence (1 reference)
clinicaltrials:NCT00001159 SUPPORT Other
"These conditions may include: hypothyroidism, hyperthyroidism, thyroid hormone resistance, Graves' Dermopathy, and thyroid-stimulating hormone (TSH) secreting pituitary adenomas."
Confirms this natural-history study explicitly covers both RTH-beta and its key differential diagnosis (TSHoma).
{ }

Source YAML

click to show 
name: Generalized Resistance to Thyroid Hormone
creation_date: "2026-08-27T05:16:42Z"
category: Mendelian
disease_term:
  preferred_term: generalized resistance to thyroid hormone
  term:
    id: MONDO:0009043
    label: generalized resistance to thyroid hormone
parents:
- thyroid hormone resistance syndrome
- hyperthyroidism
description: >-
  Generalized resistance to thyroid hormone (MONDO:0009043) is the classic,
  autosomal dominant form of resistance to thyroid hormone beta (RTH-beta),
  caused by dominant-negative mutations in the thyroid hormone receptor beta
  (THRB) gene. It produces a paradoxical biochemical signature — elevated
  circulating free T4 and/or free T3 together with a non-suppressed (normal or
  inappropriately elevated) TSH — because the pituitary thyrotroph itself is
  hormone-resistant and fails to shut off TSH secretion despite high
  circulating hormone. The mutant receptor's mutations cluster in the
  ligand-binding domain: it retains its DNA-binding and heterodimerization
  functions but fails to release corepressor and recruit coactivators
  normally triggered by T3 binding, so it silences T3-target genes even in the
  presence of the co-expressed wild-type receptor. RTH-beta is further
  described by three overlapping clinical categories depending on which
  tissues manifest resistance — "generalized" (pituitary and peripheral
  tissues both resistant, the category MONDO:0009043 models), "pituitary"
  (hyperthyroid-range biochemistry with inappropriate TSH secretion), and
  "peripheral" (hypothyroid-range signs despite normal TSH) — though in
  practice the clinical spectrum is a continuum rather than three discrete
  entities, even among relatives sharing the same THRB mutation. This is the
  pathophysiological mirror image of thyroid hormone *deficiency* (see the
  `hypothyroidism_thyroid_hormone_deficiency` module and
  `Congenital_Hypothyroidism`): here, circulating hormone is normal-to-high but
  target tissues cannot use it, rather than hormone being insufficiently
  produced.
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0009043
      label: generalized resistance to thyroid hormone
    mapping_predicate: skos:exactMatch
has_subtypes:
- name: RTH-beta
  display_name: RTH-beta (THRB dominant-negative)
  description: >-
    The classic and commonest form of generalized RTH (roughly 85% of cases),
    caused by heterozygous dominant-negative missense mutations in THRB that
    cluster in three hot-spot regions of the ligand-binding domain bordering
    the T3-binding pocket. The mutant TRβ retains DNA binding and RXR
    heterodimerization but binds T3 poorly and fails to release the
    NCoR/SMRT corepressor complex, so it continues to repress T3-target genes
    and dominantly inhibits the co-expressed wild-type receptor. Clinically
    heterogeneous, ranging from goiter and tachycardia (relative peripheral
    thyrotoxicosis in TRα-dominant tissues) to attention and learning
    difficulties, with biochemically elevated free T4/free T3 and a
    non-suppressed TSH.
  mappings:
    mondo_mappings:
    - term:
        id: MONDO:0008569
        label: thyroid hormone resistance, generalized, autosomal dominant
      mapping_predicate: skos:exactMatch
  genes:
  - preferred_term: THRB
    term:
      id: hgnc:11799
      label: THRB
  inheritance:
  - name: Autosomal dominant (RTH-beta)
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    description: >-
      Most RTH-beta cases arise from heterozygous dominant-negative THRB
      mutations; a minority of families show autosomal recessive
      transmission (MONDO:0010131), reflecting complete rather than partial
      loss of corepressor-release function.
pathophysiology:
- name: THRB Dominant-Negative Receptor Formation
  description: >-
    Heterozygous missense mutations in THRB cluster in three hot-spot regions
    of the ligand-binding domain that border the T3-binding pocket. The
    mutant TRβ protein retains its DNA-binding domain and its capacity to
    heterodimerize with RXR at thyroid hormone response elements, but its
    hormone-binding pocket is distorted, so it binds T3 with markedly reduced
    affinity.
  role: trigger
  biological_scale: MOLECULAR
  genetic_context:
    functional_impact_category: DOMINANT_NEGATIVE
    allele_type: missense
  molecular_functions:
  - preferred_term: Thyroid hormone receptor (TRβ) DNA/RXR-binding activity
    term:
      id: GO:0004879
      label: nuclear receptor activity
  evidence:
  - reference: PMID:15988389
    reference_title: "Syndromes of thyroid hormone resistance."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      these three clusters of mutations border the T3-binding pocket
    explanation: >-
      Localizes the RTH-beta mutation hot spots to the T3-binding pocket of
      the ligand-binding domain, consistent with a receptor that keeps its
      DNA-binding/dimerization function but loses normal hormone binding.
  downstream:
  - target: Impaired Corepressor Release at Thyroid Hormone Response Elements
- name: Impaired Corepressor Release at Thyroid Hormone Response Elements
  description: >-
    Because the mutant receptor cannot undergo the normal T3-induced
    conformational change, it fails to release the nuclear receptor
    corepressor complex (NCoR/SMRT) that is bound in the unliganded state, and
    correspondingly fails to recruit coactivators. The mutant receptor
    continues to occupy DNA at thyroid hormone response elements, so the
    corepressor block is not a loss of binding but a persistence of the
    repressive complex despite the presence of circulating hormone.
  role: amplifier
  biological_scale: MOLECULAR
  molecular_functions:
  - preferred_term: Persistent NCoR/SMRT corepressor binding by mutant TRβ
    term:
      id: GO:0001222
      label: transcription corepressor binding
  evidence:
  - reference: PMID:15988389
    reference_title: "Syndromes of thyroid hormone resistance."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      most TRB mutations impair the hormone binding to the receptor and
      interfere with the mechanism(s) of corepressor release and the
      consequent recruitment of coactivators
    explanation: >-
      Directly states the corepressor-release failure and coactivator
      recruitment failure that follow from impaired T3 binding.
  - reference: PMID:9647743
    reference_title: "Requirement of corepressor binding of thyroid hormone receptor mutants for dominant negative inhibition."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      association of corepressor with the RTH mutants through the hinge
      region is crucial for their dominant negative activity
    explanation: >-
      Cell-transfection evidence that continued corepressor association
      (rather than loss of DNA binding or RXR dimerization, which were
      unaffected) is the molecular requirement for dominant-negative activity.
  downstream:
  - target: Dominant-Negative Inhibition of Wild-Type Receptor Transcription
- name: Dominant-Negative Inhibition of Wild-Type Receptor Transcription
  description: >-
    Because the mutant receptor still dimerizes with RXR and binds DNA
    normally, it competes with the co-expressed wild-type TRβ (and TRα) for
    response-element occupancy and RXR partnering. The persistent
    corepressor complex it carries therefore silences T3-target gene
    transcription genome-wide, not only at alleles it occupies alone — the
    defining dominant-negative mechanism that distinguishes RTH-beta from a
    simple loss-of-function receptor null.
  role: central_effector
  biological_scale: CELLULAR
  biological_processes:
  - preferred_term: Dominant-negative suppression of thyroid hormone receptor signaling
    term:
      id: GO:0002156
      label: negative regulation of thyroid hormone receptor signaling pathway
    modifier: GAIN_OF_FUNCTION
  evidence:
  - reference: PMID:15988389
    reference_title: "Syndromes of thyroid hormone resistance."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The lack of interaction with coactivators appears to be an additional
      mechanism for the dominant negative effects of mutant TRB on the
      transcriptional activity of the normal receptor.
    explanation: >-
      States explicitly that the mutant receptor suppresses transcriptional
      activity driven by the co-expressed normal (wild-type) receptor, the
      hallmark of a dominant-negative rather than simple loss-of-function
      mechanism.
  downstream:
  - target: Pituitary Thyrotroph Resistance to Feedback
  - target: Tissue-Selective Peripheral Resistance
- name: Pituitary Thyrotroph Resistance to Feedback
  description: >-
    Pituitary thyrotrophs predominantly express TRβ2. Dominant-negative
    inhibition of TRβ2-mediated transcription blunts the thyrotroph's ability
    to sense elevated circulating hormone, so the normal negative-feedback
    suppression of TSH secretion is lost even as free T4/T3 rise.
  role: amplifier
  biological_scale: TISSUE
  cell_types:
  - preferred_term: Pituitary thyrotroph
    term:
      id: CL:0000476
      label: thyrotroph
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      inappropriate secretion of thyroid-stimulating hormone (TSH, normal or
      elevated).
    explanation: >-
      Documents the inappropriate (non-suppressed) TSH secretion that follows
      from thyrotroph resistance to the negative feedback signal.
  downstream:
  - target: Elevated Thyroid Hormone with Non-Suppressed TSH
- name: Tissue-Selective Peripheral Resistance
  description: >-
    Peripheral tissues vary in their relative TRα/TRβ expression, so the same
    circulating hormone excess produces a mixed clinical picture: TRβ-rich
    tissues (liver, pituitary) show blunted responsiveness (contributing to
    goiter from continued TSH drive), while TRα-predominant tissues (heart,
    bone) remain relatively hormone-responsive and show signs consistent with
    the elevated circulating hormone (tachycardia), producing the clinically
    heterogeneous, tissue-selective phenotype characteristic of RTH-beta.
  role: amplifier
  biological_scale: TISSUE
  evidence:
  - reference: PMID:31588528
    reference_title: "Syndromes of Resistance to Thyroid Hormone Action."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The phenotypic manifestations of RTHβ and RTHα are to some extent
      correlated with the degree of disruption and the tissue distribution of
      the TRs being characterized by variable coexistence of hypothyroid or
      thyrotoxic manifestations in RTHβ
    explanation: >-
      Directly attributes the mixed hypothyroid/thyrotoxic clinical picture of
      RTH-beta to differential tissue distribution of TRα versus TRβ.
  downstream:
  - target: Elevated Thyroid Hormone with Non-Suppressed TSH
- name: Elevated Thyroid Hormone with Non-Suppressed TSH
  description: >-
    The net systemic result of thyrotroph resistance and continued TSH drive
    on an otherwise intact thyroid gland is the paradoxical biochemical
    signature that defines generalized RTH: elevated circulating free T4
    and/or free T3 together with a measurable, non-suppressed TSH — a
    combination that in a gland with normal feedback would instead produce
    thyrotoxicosis with suppressed TSH.
  role: effector
  biological_scale: ORGANISM
  evidence:
  - reference: PMID:31588528
    reference_title: "Syndromes of Resistance to Thyroid Hormone Action."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      characterized by elevated circulating levels of T4 and T3 with
      measurable serum TSH concentrations
    explanation: >-
      States the defining paradoxical biochemical signature of generalized
      RTH directly.
  downstream:
  - target: Tissue-Selective Mixed Hypothyroid/Thyrotoxic Phenotype
- name: Tissue-Selective Mixed Hypothyroid/Thyrotoxic Phenotype
  description: >-
    Clinically, patients present with a heterogeneous mixture of features:
    goiter and attention/learning difficulties (relative hormone
    insensitivity in TRβ-predominant tissues) alongside resting tachycardia
    (relative hormone excess acting through relatively intact TRα in
    cardiac tissue). Severity and the balance of hypothyroid versus
    thyrotoxic features vary between and even within families carrying the
    same THRB mutation.
  role: consequence
  biological_scale: ORGANISM
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Clinical manifestations of RTH-β vary from hyperthyroidism to
      hypothyroidism or simple goiter, and RTH-β is often misdiagnosed
      clinically.
    explanation: >-
      Documents the clinically heterogeneous, tissue-selective phenotype
      spanning apparent hyperthyroid and hypothyroid presentations.
  downstream:
  - target: Goiter
  - target: Resting Tachycardia
  - target: Attention Deficit Hyperactivity Disorder
  - target: Thyroid Nodules
phenotypes:
- name: Goiter
  category: Endocrine
  subtype: RTH-beta
  frequency: FREQUENT
  description: >-
    Diffuse thyroid enlargement driven by the sustained TSH stimulation that
    results from pituitary thyrotroph resistance to thyroid hormone feedback.
  phenotype_term:
    preferred_term: Goiter
    term:
      id: HP:0000853
      label: Goiter
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      About 65–95% of the RTH-β patients have goiter
    explanation: >-
      Directly states the frequency of goiter in RTH-beta patients.
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Goiter is frequently observed in individuals with RTHβ but is usually
      of little consequence.
    explanation: >-
      Independent confirmation that goiter is a frequent clinical finding in
      RTH-beta.
- name: Resting Tachycardia
  category: Cardiovascular
  subtype: RTH-beta
  description: >-
    Sinus tachycardia reflecting relative hormone excess acting through
    relatively intact TRα-mediated cardiac responsiveness, despite
    TRβ-mediated resistance elsewhere.
  phenotype_term:
    preferred_term: Tachycardia
    term:
      id: HP:0001649
      label: Tachycardia
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      other symptoms include sinus tachycardia
    explanation: >-
      Directly names sinus tachycardia as a reported RTH-beta symptom.
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      producing sinus tachycardia in the heart expressing mainly the WT TRα
      and goiter by TSH stimulation, as the pituitary expresses mainly TRβ
      including the mutant form
    explanation: >-
      Explains the mechanistic basis of tachycardia as relatively intact
      TRα-mediated cardiac responsiveness to the elevated circulating hormone.
- name: Attention Deficit Hyperactivity Disorder
  category: Neurologic
  subtype: RTH-beta
  frequency: FREQUENT
  description: >-
    Attention deficit hyperactivity disorder is a well-documented
    neurodevelopmental feature of RTH-beta, reported in roughly half to
    four-fifths of affected individuals.
  phenotype_term:
    preferred_term: Attention deficit hyperactivity disorder
    term:
      id: HP:0007018
      label: Attention deficit hyperactivity disorder
  evidence:
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Attention deficit disorder (ADHD), reported in 48-83% of individuals
      with RTHβ, is treated using conventional drugs.
    explanation: >-
      Directly states the reported frequency of ADHD in RTH-beta and names
      the finding explicitly, rather than a generic disease definition.
- name: Thyroid Nodules
  category: Endocrine
  subtype: RTH-beta
  description: >-
    Thyroid nodules, including rare reported cases of papillary thyroid
    carcinoma, may co-exist with RTH-beta; because thyroidectomy and
    radioactive iodine in RTH-beta leave persistently high TSH and difficult
    subsequent levothyroxine replacement, most nodules are managed
    conservatively.
  phenotype_term:
    preferred_term: Thyroid nodule
    term:
      id: HP:0025388
      label: Thyroid nodule
  evidence:
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Thyroid nodules are quite prevalent in the general population and thus
      may occasionally co-exist with RTHβ. Although the majority of thyroid
      nodules are benign and do not require surgical management, there are
      few reported cases of papillary thyroid carcinoma in patients with
      RTHβ.
    explanation: >-
      Documents thyroid nodules, including rare papillary carcinoma cases, as
      a recognized co-occurring finding in RTH-beta.
biochemical:
- name: Serum Free Thyroxine (Free T4)
  subtype: RTH-beta
  notes: >-
    Free T4 is elevated in essentially all untreated RTH-beta patients. The
    10.0-25.0 pmol/L band below is a conventional adult clinical laboratory
    reference interval with no single citable primary source (assay- and
    age-dependent), recorded here per the same convention used in
    Allan-Herndon-Dudley_Syndrome rather than attributed to a fabricated
    citation; the sourced RTH-beta anchor is the pretreatment cohort mean of
    30 pmol/L cited below.
  presence: INCREASED
  reference_ranges:
  - loinc_term:
      id: LOINC:14920-3
      label: Thyroxine (T4) free [Moles/volume] in Serum or Plasma
    lower_bound: 10.0
    upper_bound: 25.0
    unit: pmol/L
    population: >-
      Adults; conventional clinical laboratory interval, assay- and
      age-dependent.
    notes: >-
      This interval is a conventional adult clinical laboratory range with no
      single citable primary source, so it is recorded here rather than
      attributed to a fabricated citation. The RTH-beta-specific anchor that
      IS sourced is the pretreatment cohort mean of 30 pmol/L.
    evidence:
    - reference: PMID:41131705
      reference_title: "TRIAC Therapy Relieves Hyperthyroid Symptoms, Lowering T4, T3, and Metabolic Rate in Resistance to Thyroid Hormone β."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        normalized circulating free T4 (baseline free T4 30 pmol/L vs
        posttreatment 17 pmol/L; P = .007)
      explanation: >-
        Marked PARTIAL because it reports the pretreatment RTH-beta cohort
        mean (30 pmol/L, elevated above the conventional adult interval)
        rather than the reference interval itself; also documents that TRIAC
        normalized this value.
    interpretation_bands:
    - name: Elevated free T4 typical of untreated RTH-beta
      lower_bound: 25.0
      unit: pmol/L
      abnormal_flag: HIGH
      phenotype_term:
        preferred_term: Increased circulating free T4
        term:
          id: HP:0033077
          label: Increased circulating free T4 concentration
      interpretation: >-
        Elevated free T4 alongside a non-suppressed TSH (rather than the
        suppressed TSH expected with primary hyperthyroidism) should prompt
        consideration of RTH-beta and THRB sequencing.
- name: Serum Thyroid-Stimulating Hormone (TSH)
  subtype: RTH-beta
  notes: >-
    The diagnostic hallmark of generalized RTH-beta is that TSH is measurable
    and not suppressed despite elevated free thyroid hormone, in contrast to
    primary hyperthyroidism (thyrotoxicosis) where TSH is suppressed. The
    0.4-4.0 mU/L band below is a conventional adult clinical laboratory
    reference interval with no single citable primary source, recorded here
    per the same convention used in Allan-Herndon-Dudley_Syndrome.
  presence: NORMAL
  reference_ranges:
  - loinc_term:
      id: LOINC:3016-3
      label: Thyrotropin [Units/volume] in Serum or Plasma
    lower_bound: 0.4
    upper_bound: 4.0
    unit: mU/L
    population: Adults; conventional clinical laboratory interval, assay-dependent.
    notes: >-
      This interval is a conventional adult clinical laboratory range with no
      single citable primary source and is recorded here rather than
      attributed to a fabricated citation. The RTH-beta-specific anchor that
      IS sourced is the pretreatment cohort mean TSH of 2.1 mU/L, which is
      squarely within this interval despite the concurrently elevated free T4.
    evidence:
    - reference: PMID:41131705
      reference_title: "TRIAC Therapy Relieves Hyperthyroid Symptoms, Lowering T4, T3, and Metabolic Rate in Resistance to Thyroid Hormone β."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        without any rise in their serum TSH (baseline 2.1 mU/L vs
        posttreatment 1.7 mU/L; P = .65)
      explanation: >-
        Marked PARTIAL because it reports the pretreatment cohort mean TSH
        (2.1 mU/L) rather than the reference interval itself; documents a
        normal-range TSH coexisting with an elevated free T4 (30 pmol/L) in
        the same untreated RTH-beta cohort, the paradoxical
        non-suppressed-TSH signature.
    interpretation_bands:
    - name: Non-suppressed (inappropriately normal) TSH despite elevated thyroid hormone
      lower_bound: 0.4
      upper_bound: 4.0
      unit: mU/L
      abnormal_flag: NORMAL
      phenotype_term:
        preferred_term: Inappropriately normal thyroid-stimulating hormone level
        term:
          id: HP:0033075
          label: Inappropriately normal thyroid-stimulating hormone level
      interpretation: >-
        A TSH within, or only mildly above, the standard reference interval
        is abnormal in the specific context of a concurrently elevated free
        T4/T3 — it should be suppressed in that setting, and its failure to
        suppress is the defining paradox of generalized RTH-beta.
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      inappropriate secretion of thyroid-stimulating hormone (TSH, normal or
      elevated).
    explanation: >-
      States directly that TSH secretion is inappropriate (not suppressed) in
      RTH-beta despite the concurrent free hormone elevation.
- name: Serum Free Triiodothyronine (Free T3)
  subtype: RTH-beta
  notes: >-
    Free/total T3 is elevated alongside free T4 in most RTH-beta patients.
  presence: INCREASED
  reference_ranges:
  - unit: pmol/L
    population: Adults; conventional clinical laboratory interval, assay-dependent.
    notes: >-
      No single citable primary source states a numeric normal interval for
      this analyte in this cohort, so only the qualitative interpretation
      band is recorded (no lower_bound/upper_bound), grounded in the RTH-beta
      biochemical-triad evidence below rather than a fabricated numeric range.
    interpretation_bands:
    - name: Elevated free T3 typical of untreated RTH-beta
      abnormal_flag: HIGH
      phenotype_term:
        preferred_term: Increased circulating free T3
        term:
          id: HP:0011788
          label: Increased circulating free T3
      interpretation: >-
        Elevated free T3 alongside elevated free T4 and a non-suppressed TSH
        is the characteristic RTH-beta biochemical triad.
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      increased serum levels of free triiodothyronine (FT3) and/or free
      thyroxine (FT4)
    explanation: Directly documents the elevated FT3/FT4 biochemical signature of RTH-beta.
genetic:
- name: THRB
  gene_term:
    preferred_term: THRB
    term:
      id: hgnc:11799
      label: THRB
  relationship_type: CAUSATIVE
  frequency: causes the large majority (~85%) of clinically recognized RTH-beta
  notes: >-
    Dominant-negative missense variants clustering in the ligand-binding
    domain hot spots that border the T3-binding pocket; 236 different
    mutations across 805 families had been reported as of 2021. Inheritance
    is typically autosomal dominant because the mutant receptor dimerizes
    with, and interferes with, the wild-type receptor; homozygous variants
    (lacking a wild-type allele) are clinically more severe. In about 14% of
    individuals with the RTH-beta phenotype no THRB mutation is identified.
  evidence:
  - reference: PMID:15988389
    reference_title: "Syndromes of thyroid hormone resistance."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      About 85% of patients with RTH are harboring mutations in thyroid
      hormone receptor beta (TRB).
    explanation: Quantifies THRB as the causal gene in the large majority of RTH-beta cases.
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      236 different mutations in 805 families have been identified. They are
      located in the functional areas of the ligand (T3)-binding domain and
      adjacent hinge region.
    explanation: >-
      Quantifies the mutation spectrum and confirms the ligand-binding-domain
      and hinge-region clustering already modeled in the pathophysiology
      chain.
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The inheritance of RTHβ is typically autosomal dominant. This is
      explained by the formation of dimers between the mutant and normal
      (wild-type; WT) TH receptor (TR) interfering with the function of the
      WT TRβ.
    explanation: >-
      States the dominant-negative dimerization mechanism underlying
      autosomal dominant inheritance, directly supporting the
      genetic_context.functional_impact_category: DOMINANT_NEGATIVE modeling
      used on the corresponding pathophysiology node.
treatments:
- name: TRIAC (Triiodothyroacetic Acid) Therapy for RTH-beta
  description: >-
    TRIAC is a thyromimetic that binds thyroid hormone receptors with high
    affinity but is not well measured by standard T4/T3 assays; it acts on
    the mutant/wild-type receptor pool to relieve pituitary and peripheral
    hyperthyroid-range signaling while lowering circulating T4/T3, without
    exacerbating hormone resistance in already-resistant tissues.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: tiratricol
      term:
        id: CHEBI:40021
        label: tiratricol
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Tissue-Selective Peripheral Resistance
    treatment_effect: MODULATES
    description: >-
      TRIAC acts as a thyroid hormone receptor agonist to relieve
      hyperthyroid-range symptoms driven by relatively hormone-responsive
      tissues while lowering circulating free T4/T3 and resting energy
      expenditure, without worsening resistance in already hormone-resistant
      tissues (e.g., liver).
    evidence:
    - reference: PMID:41131705
      reference_title: "TRIAC Therapy Relieves Hyperthyroid Symptoms, Lowering T4, T3, and Metabolic Rate in Resistance to Thyroid Hormone β."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        TRIAC therapy in RTHβ relieves hyperthyroid symptoms and lowers
        resting energy expenditure and circulating thyroid hormones without
        worsening hepatic hormone resistance or exacerbating cardiac
        thyromimetic activity.
      explanation: >-
        Direct clinical-trial evidence for the mechanism and effect of TRIAC
        therapy on the tissue-selective resistance/thyrotoxicosis balance in
        RTH-beta.
  evidence:
  - reference: PMID:41131705
    reference_title: "TRIAC Therapy Relieves Hyperthyroid Symptoms, Lowering T4, T3, and Metabolic Rate in Resistance to Thyroid Hormone β."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The treatment of resistance to thyroid hormone β (RTHβ) is challenging
      because features of hyperthyroidism in some tissues coexist with a
      hormone-resistant, hypothyroid state in other organs.
    explanation: >-
      Frames why RTH-beta cannot be treated with conventional
      antithyroid/levothyroxine approaches and motivates the
      receptor-selective TRIAC strategy.
  - reference: PMID:41131705
    reference_title: "TRIAC Therapy Relieves Hyperthyroid Symptoms, Lowering T4, T3, and Metabolic Rate in Resistance to Thyroid Hormone β."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      nadir FT4 concentrations fell to within the reference interval in all
      but 1 patient
    explanation: >-
      Confirms TRIAC normalized free T4 into the reference interval in nearly
      all treated patients, not merely a partial reduction.
- name: Beta-Adrenergic Blockade (Atenolol) for RTH-beta Tachycardia
  description: >-
    Selective beta-blockade with atenolol is used to control the resting
    tachycardia produced by relatively intact TRα-mediated cardiac
    responsiveness to the elevated circulating hormone. Atenolol is preferred
    over non-selective agents because it does not inhibit peripheral T4-to-T3
    conversion, avoiding a further rise in T3.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: atenolol
      term:
        id: CHEBI:2904
        label: atenolol
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Resting Tachycardia
    treatment_effect: MODULATES
    description: >-
      Beta-adrenergic blockade symptomatically controls the tachycardia
      arising from relatively hormone-responsive cardiac TRα signaling,
      without correcting the underlying receptor defect.
    evidence:
    - reference: PMID:33176840
      reference_title: "Update on resistance to thyroid hormone syndromeβ."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Selective beta-blockers can be considered for patients with obvious
        tachycardia during resting. Because atenolol cannot inhibit the
        conversion of T4 to T3, it is the best choice for RTH-β with
        tachycardia.
      explanation: >-
        Directly recommends atenolol specifically (over non-selective
        beta-blockers) for RTH-beta tachycardia and states the rationale.
  evidence:
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      beta blockade may be employed to help with tachycardia
    explanation: Independent confirmation of beta-blockade as symptomatic tachycardia management.
- name: Supraphysiologic Intermittent Liothyronine (L-T3) and Avoidance of Ablative Therapy
  description: >-
    Because thyroidectomy and radioactive iodine reduce the intact wild-type
    receptor's compensatory hormone supply and leave persistently elevated
    TSH driving pituitary hyperplasia and recurrent goiter, ablative therapy
    is generally avoided in RTH-beta. Instead, supraphysiologic doses of
    liothyronine (L-T3) given intermittently (e.g., every other day) achieve
    a brief high peak that suppresses TSH and shrinks goiter, or improves
    ADHD/cognitive symptoms, without sustaining thyrotoxic hormone levels
    long enough to cause thyrotoxic side effects.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: liothyronine (L-T3)
      term:
        id: CHEBI:18258
        label: 3,3',5-triiodo-L-thyronine
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Pituitary Thyrotroph Resistance to Feedback
    treatment_effect: MODULATES
    description: >-
      A brief supraphysiologic L-T3 peak given intermittently suppresses TSH
      below the level needed to drive thyroid growth, without sustaining
      elevated hormone long enough to produce thyrotoxic symptoms.
    evidence:
    - reference: PMID:33868182
      reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        An approach of administering supraphysiologic doses of T3 every other
        day
      explanation: >-
        States the intermittent supraphysiologic L-T3 dosing strategy used to
        suppress TSH and shrink goiter without inducing thyrotoxic symptoms.
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      radioactive iodine and surgical treatment are not recommended because
      they may lead to pituitary hyperplasia
    explanation: >-
      States directly that ablative therapy is not recommended in RTH-beta
      and names the specific complication (pituitary hyperplasia) it risks.
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Caution should be exercised in the reduction of TH levels with
      antithyroid medication and ablative therapies (radioactive iodine or
      surgery) as it leads to difficulty in the subsequent treatment of
      hypothyroidism.
    explanation: >-
      Independent confirmation of the avoid-ablative-therapy guidance and its
      rationale (subsequent hypothyroidism management difficulty).
prevalence:
- population: Live births (pooled newborn TSH/T4 screening surveys)
  measure_type: BIRTH_PREVALENCE
  prevalence_class: BAND_1_9_PER_100000
  rate_low: 2.5
  rate_high: 5.26
  notes: >-
    Two newborn screening surveys (80,884 and 74,992 infants) identified 2 and
    4 THRB mutation carriers respectively, giving prevalence estimates of 1 in
    40,000 and 1 in 19,000 live births.
  evidence:
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Surveys of 80,884 and 74,992 newborns using TSH and T4 measurements
      identified 2 and 4 infants with THRB gene mutations indicating a
      prevalence of 1 in 40,000 and 1 in 19,000 live births respectively
    explanation: >-
      Reports the two newborn-screening-based prevalence estimates directly.
diagnosis:
- name: THRB Genetic Testing
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: NCIT:C15709
      label: Genetic Testing
  description: >-
    Sequencing THRB, focused on the ligand-binding domain and hinge region
    where mutations cluster.
  results: >-
    Identification of a THRB mutation confirms the diagnosis, though roughly
    14% of individuals with the classic RTH-beta phenotype have no
    identifiable THRB mutation (mosaicism or regulatory-region variants have
    been proposed to explain some of these cases).
  evidence:
  - reference: PMID:33176840
    reference_title: "Update on resistance to thyroid hormone syndromeβ."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Genetic diagnosis is the gold standard for RTH-β currently
    explanation: States genetic testing as the diagnostic gold standard for RTH-beta.
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In 14% of individuals manifesting the RTHβ phenotype no THRB mutations
      were identified.
    explanation: Quantifies the fraction of clinically diagnosed cases with no identifiable THRB mutation.
- name: Serum TSH Determination
  diagnosis_term:
    preferred_term: serum TSH measurement
    term:
      id: NCIT:C74742
      label: Hormone Measurement
  description: >-
    Measuring serum TSH alongside free T4/T3 is the most sensitive
    biochemical test to detect reduced sensitivity to thyroid hormone; other
    peripheral markers of TH action (cholesterol, creatine kinase, alkaline
    phosphatase, osteocalcin, SHBG) are less reliable unless measured before
    and after T3 administration.
  results: >-
    A non-suppressed (measurable, normal, or elevated) TSH in the presence of
    elevated free T4/T3 supports RTH-beta over primary hyperthyroidism.
  evidence:
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Serum TSH determination remains the most sensitive test to determine
      reduced sensitivity to TH.
    explanation: States TSH determination as the most sensitive test directly.
differential_diagnoses:
- name: TSH-Secreting Pituitary Adenoma (TSHoma)
  disease_term:
    preferred_term: TSH-secreting pituitary adenoma
    term:
      id: MONDO:0019611
      label: TSH-secreting pituitary adenoma
  description: >-
    The principal condition to exclude, particularly when there is no family
    history: TSHoma also produces elevated free thyroid hormone with a
    non-suppressed TSH. Testing first-degree relatives for the biochemical
    phenotype is a cost-effective way to support RTH-beta over TSHoma, since
    incidental pituitary lesions are found in up to 24% of RTH-beta patients,
    complicating imaging-based differentiation.
  distinguishing_features:
  - Failure to suppress TSH after supraphysiologic T3 administration
  - Failure to normally stimulate TSH with TRH
  - Elevated serum SHBG
  - Increased pituitary alpha-glycoprotein/TSH molar ratio
  - Frequent co-secretion of growth hormone or prolactin, with an imaging-confirmed pituitary mass
  evidence:
  - reference: PMID:33868182
    reference_title: "Resistance to Thyroid Hormone Beta: A Focused Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Characteristics of a TSH-oma include failure to suppress TSH after the
      administration of supra-physiologic doses of T3, failure to normally
      stimulate TSH with TSH releasing hormone (TRH)
    explanation: >-
      Directly states the biochemical dynamic-testing features that
      distinguish TSHoma from RTH-beta.
clinical_trials:
- name: NCT06307990
  phase: NOT_APPLICABLE
  status: RECRUITING
  description: >-
    Observational study (ADAM-THAD) characterizing the neurological and
    cardiological phenotype of RTH-beta and RTH-alpha patients, aiming to
    define frequency, accelerate diagnosis, and develop monitoring tools;
    also generates patient-derived iPSCs to study molecular mechanisms.
  evidence:
  - reference: clinicaltrials:NCT06307990
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The goal of this observational study is to learn about the neurological
      and cardiological phenotype of patients with resistance to thyroid
      hormone (RTH) syndromes beta and alpha (RTHß and RTHa) due to dominant
      negative variants in the genes encoding the thyroid hormone receptors
      alpha (THRA) and beta (THRB).
    explanation: >-
      Confirms this recruiting observational study's direct relevance to
      RTH-beta natural history and diagnosis; it also enrolls RTH-alpha
      patients, which is out of this entry's MONDO:0009043 scope but does not
      change the RTH-beta relevance.
- name: NCT00001159
  phase: NOT_APPLICABLE
  status: RECRUITING
  description: >-
    NIH Clinical Center natural-history platform for thyroid function
    disorders broadly, explicitly including thyroid hormone resistance and
    TSH-secreting pituitary adenomas (the key differential diagnosis).
  evidence:
  - reference: clinicaltrials:NCT00001159
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      These conditions may include: hypothyroidism, hyperthyroidism, thyroid
      hormone resistance, Graves' Dermopathy, and thyroid-stimulating hormone
      (TSH) secreting pituitary adenomas.
    explanation: >-
      Confirms this natural-history study explicitly covers both RTH-beta and
      its key differential diagnosis (TSHoma).
references:
- reference: PMID:25905294
  title: "Impaired Sensitivity to Thyroid Hormone: Defects of Transport, Metabolism, and Action."
notes: >-
  This entry is scoped to MONDO:0009043 (generalized resistance to thyroid
  hormone), which MONDO places specifically under THRB-caused RTH-beta as the
  "generalized" (pituitary-and-peripheral) clinical category, not as an
  umbrella over every mechanism of impaired thyroid hormone sensitivity. The
  originating issue suggested modeling RTH-alpha (THRA, MONDO:0034216), MCT8
  deficiency (SLC16A2, MONDO:0010354), and SECISBP2 deficiency
  (MONDO:0800046) as has_subtypes of this entry; checking MONDO directly
  showed that only MONDO:0008569 (the autosomal dominant RTH-beta form) is
  actually a child of MONDO:0009043 -- RTH-alpha is a sibling under thyroid
  hormone resistance syndrome (MONDO:0001328), Allan-Herndon-Dudley syndrome
  sits under X-linked syndromic intellectual disability, and SECISBP2
  deficiency sits under peripheral hypothyroidism. has_subtypes terms count
  toward MONDO coverage, so modeling those three as subtypes here would also
  have double-claimed two already separately curated entries. This entry
  follows MONDO's actual hierarchy rather than the issue's suggested list.

  RTH-alpha, MCT8 deficiency (Allan-Herndon-Dudley syndrome), and SECISBP2
  deficiency remain closely related, mechanistically analogous forms of
  reduced tissue sensitivity to thyroid hormone (together with RTH-beta, the
  scope of the 2024 European Thyroid Association guideline,
  DOI:10.1530/etj-24-0125), and are cross-referenced here rather than modeled
  as subtypes: MCT8 deficiency is fully curated as Allan-Herndon-Dudley_Syndrome
  (MONDO:0010354), SECISBP2 deficiency as SECISBP2_Deficiency (MONDO:0800046),
  and RTH-alpha (MONDO:0034216) is not yet separately curated in dismech. This
  is also the contrasting resistance-vs-deficiency entity to
  Congenital_Hypothyroidism and the hypothyroidism_thyroid_hormone_deficiency
  module: in RTH-beta, circulating thyroid hormone is normal-to-elevated but
  target tissues under-respond to it, whereas hypothyroidism is a deficiency
  of circulating hormone itself. The two conditions are deliberately NOT
  modeled with conforms_to against the hypothyroidism module, since
  RTH-beta's mechanism (receptor resistance despite adequate-to-excess
  hormone) is the mechanistic inverse, not a variant, of hormone deficiency.

  No dedicated GeneReviews chapter exists for RTH-beta, RTH-alpha, or
  SECISBP2 deficiency; the baseline clinical reference actually consulted for
  these three is the Endotext chapter "Impaired Sensitivity to Thyroid
  Hormone: Defects of Transport, Metabolism, and Action" (PMID:25905294,
  tagged above under references), not GeneReviews. A GeneReviews chapter does
  exist for the MCT8/Allan-Herndon-Dudley arm (PMID:20301789) and is already
  cited extensively in the standalone Allan-Herndon-Dudley_Syndrome entry.

  Deliberately deferred in this pass, for lack of RTH-beta-specific verified
  human evidence located within the curation time budget rather than any
  judgment that they are irrelevant: sensorineural hearing impairment, atrial
  fibrillation, and hepatic steatosis/dyslipidemia as separately evidenced
  phenotypes, and a structured animal_models entry for the TRb knockout/GS
  mouse literature (e.g., DOI:10.1101/2023.11.26.568063, cached but not yet
  cited). A hearing-related synonym ("deafness-thyroid hormone resistance
  syndrome") is recorded on MONDO:0009043 itself and may warrant follow-up.
📚

References & Deep Research

References

1
PMID:25905294
Impaired Sensitivity to Thyroid Hormone: Defects of Transport, Metabolism, and Action.
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
Generalized Resistance to Thyroid Hormone: Disease Characteristics Report
Edison Scientific Literature 20 citations 2026-08-26T22:47:34.142392

Generalized Resistance to Thyroid Hormone: Disease Characteristics Report

Scope and terminology

Generalized resistance to thyroid hormone (GRTH) is the historical name for reduced tissue responsiveness to thyroid hormone affecting the hypothalamic–pituitary–thyroid axis and peripheral tissues. Most molecularly confirmed cases are now termed resistance to thyroid hormone beta (RTHβ). This distinction matters: RTHα, defects of hormone transport such as MCT8 deficiency, and defects of hormone metabolism are separate disorders. “Generalized,” “pituitary,” and “peripheral” RTH were originally clinical subdivisions, but they overlap and are less useful than molecular classification.

The strongest current authority is the 2024 European Thyroid Association (ETA) guideline, published July 2024 (DOI 10.1530/ETJ-24-0125). Its abstract states: “Impaired sensitivity to thyroid hormones encompasses disorders with defective transport of hormones into cells, reduced hormone metabolism, and resistance to hormone action,” and emphasizes that diagnosis combines clinical features with pathogenic variants while management rests on a limited evidence base. (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 9-10)

domain core finding/statistic evidence type source/date/DOI or NCT
Disease identifiers Generalized resistance to thyroid hormone; MONDO:0009043; OMIM:188570; disease-level aggregated rare-disease/gene-disease resources link generalized RTH to THRB (OpenTargets Search: resistance to thyroid hormone-THRB, persani20242024europeanthyroid pages 9-10) Ontology/database + guideline Open Targets disease-target association context; ETA Guideline, Jul 2024, https://doi.org/10.1530/etj-24-0125
Core definition RTHβ is characterized by elevated thyroid hormones with non-suppressed TSH and variable multisystem phenotype from asymptomatic to thyrotoxic (persani20242024europeanthyroid pages 9-10, persani20242024europeanthyroid pages 2-3) Guideline/reviewed clinical evidence ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Causal gene / inheritance Causal gene: THRB; typically autosomal dominant; mutant TRβ acts in a dominant-negative manner via reduced hormone binding and/or impaired corepressor release/coactivator recruitment (persani20242024europeanthyroid pages 9-10) Mechanistic human/genetic guideline evidence ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Prevalence Reported prevalence range ~1:18,750 to 1:40,000 (buyukyılmaz2024clinicalcharacteristicsand pages 1-1, belal20247684resistanceto pages 1-2) Human cohort + case report summary Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14; Belal et al., Oct 2024, DOI:10.1210/jendso/bvae163.2063
Variant spectrum Turkish series found 8 heterozygous pathogenic/likely pathogenic missense variants in 30 genetically confirmed patients from 8 unrelated families, including 3 novel variants (buyukyılmaz2024clinicalcharacteristicsand pages 1-1, buyukyılmaz2024clinicalcharacteristicsand pages 2-3) Human cohort Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14
Variant-negative fraction About 10–15% of clinically suspected/phenotypic RTHβ cases may lack an identifiable THRB variant; possible explanations include mosaicism or noncoding/deep intronic defects (persani20242024europeanthyroid pages 9-10, buyukyılmaz2024clinicalcharacteristicsand pages 3-3, belal20247684resistanceto pages 1-2) Guideline + cohort + case summary ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125; Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14
Biochemical hallmark Typical diagnostic pattern: elevated free/total T4, elevated free/total T3, and non-suppressed or inappropriately normal/elevated TSH (persani20242024europeanthyroid pages 9-10, persani20242024europeanthyroid pages 2-3) Guideline ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Differential diagnosis Important differentials include assay interference and TSH-secreting pituitary adenoma (TSHoma); in the Turkish suspected cohort, 1/20 variant-negative patients had TSHoma (buyukyılmaz2024clinicalcharacteristicsand pages 2-3, belal20247684resistanceto pages 1-2) Cohort + case-based clinical evidence Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14; Belal et al., Oct 2024, DOI:10.1210/jendso/bvae163.2063
Pediatric/adult phenotype frequencies In the 2024 Turkish genetically confirmed cohort (n=30): 56% of children had goiter; 23% had positive thyroid autoantibodies; 7 adults had thyroid nodules; 2 adults had papillary thyroid carcinoma (buyukyılmaz2024clinicalcharacteristicsand pages 1-1, buyukyılmaz2024clinicalcharacteristicsand pages 3-3) Human cohort Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14
Clinical phenotype spectrum Many patients are asymptomatic, but reported manifestations include goiter, tachycardia/tachyarrhythmia, anxiety, sleep disturbance, ADHD/learning issues, hearing loss, color vision impairment, dyslipidemia, and increased liver fat (persani20242024europeanthyroid pages 9-10, buyukyılmaz2024clinicalcharacteristicsand pages 2-3, belal20247684resistanceto pages 1-2) Guideline + cohort + case summary ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125; Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14
Cardiovascular prognosis Guideline-level evidence notes increased risks of atrial fibrillation, myocardial infarction, heart failure, and earlier mortality in RTHβ, likely reflecting excess hormone action in TRα-expressing tissues such as myocardium (persani20242024europeanthyroid pages 9-10) Guideline/expert synthesis ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Management principles Many patients require no disease-specific therapy; avoid antithyroid drugs or thyroid ablation unless significant comorbidity/misdiagnosis issues; treatment is individualized and symptom-directed (buyukyılmaz2024clinicalcharacteristicsand pages 2-3, persani20242024europeanthyroid pages 3-5) Guideline + cohort ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125; Büyükyılmaz et al., Dec 2024, DOI:10.4274/jcrpe.galenos.2024.2024-8-14
TRIAC therapy TRIAC (triiodothyroacetic acid) is recommended/used to control thyrotoxic signs and symptoms; guideline dosing reported as 1.4–2.8 mg twice or three times daily, preferably with expert-center input (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 3-5) Guideline/expert consensus ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Other symptomatic therapy Beta-blockade can be used for adrenergic symptoms; selected reports note benefit of alternate-day supraphysiologic liothyronine (D-T3) for goiter/ADHD phenotypes (persani20242024europeanthyroid pages 9-10, belal20247684resistanceto pages 1-2) Guideline + case summary ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125; Belal et al., Oct 2024, DOI:10.1210/jendso/bvae163.2063
Surveillance Recommended follow-up includes thyroid ultrasound, anti-thyroid antibodies, cardiovascular assessment (BP, ECG ± echo, especially >30 y or symptomatic), fasting lipids/glucose, adult bone density, and pediatric growth/development/hearing/neuropsychological assessment (persani20242024europeanthyroid pages 3-5, persani20242024europeanthyroid pages 2-3) Guideline ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Pregnancy Women with RTHβ should receive multidisciplinary endocrine-obstetric care; monitoring should include fetal growth and heart rate; guideline notes increased miscarriage and small-for-gestational-age risk in affected mothers (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 3-5) Guideline/expert synthesis ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125
Active observational study Understanding, Diagnosis and Monitoring of Thyroid Hormone Action Defects; recruiting observational study; planned enrollment 150 (RTH and related thyroid hormone action defects) Clinical study registry NCT06307990, Istituto Auxologico Italiano, https://clinicaltrials.gov/study/NCT06307990
Active registry Register for Patients With Thyroid Hormone Resistance; recruiting observational registry; planned enrollment 200 Clinical study registry NCT06566066, Charité University Berlin, https://clinicaltrials.gov/study/NCT06566066
Natural history platform Natural History of Thyroid Function Disorders; recruiting observational study; planned enrollment 2500 Clinical study registry NCT00001159, NIH Clinical Center, https://clinicaltrials.gov/study/NCT00001159
Mouse model evidence TRβ mouse models show that pituitary-thyroid negative feedback depends on TRβ DNA binding; severe hearing loss occurs in TRβKO and TRβGS mice; retinal thickness/visual phenotypes support sensory-system involvement of TRβ (hones2024comparativephenotypingof pages 5-9) Animal model Hönes et al., bioRxiv, Nov 2024, DOI:10.1101/2023.11.26.568063
Translational interpretation Mouse data support human tissue selectivity: impaired central feedback and sensory phenotypes help explain unsuppressed TSH plus hearing/vision abnormalities seen clinically in RTHβ (persani20242024europeanthyroid pages 9-10, hones2024comparativephenotypingof pages 5-9) Cross-species synthesis ETA Guideline, Jul 2024, DOI:10.1530/etj-24-0125; Hönes et al., Nov 2024, DOI:10.1101/2023.11.26.568063

Table: This compact table summarizes high-value evidence for generalized resistance to thyroid hormone (RTHβ), emphasizing identifiers, genetics, biochemical diagnosis, recent cohort data, management, surveillance, ongoing studies, and translational animal findings.

1. Disease information

Definition

RTHβ is a rare, usually Mendelian disorder in which tissues show reduced sensitivity to triiodothyronine (T3), producing the characteristic biochemical combination of high free/total T4 and usually high free/total T3 with a non-suppressed TSH. Compensatory elevation of thyroid hormones maintains near-normal signaling in resistant tissues but can over-stimulate tissues in which TRα predominates, explaining simultaneous hypo-, eu-, and hyperthyroid features. The phenotype ranges from clinically asymptomatic to significant thyrotoxicosis. (persani20242024europeanthyroid pages 9-10, persani20242024europeanthyroid pages 2-3)

Identifiers and synonyms

  • MONDO: MONDO:0009043, generalized resistance to thyroid hormone.
  • Related molecular MONDO entry: MONDO:0700478, resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta.
  • OMIM: 188570, generalized resistance to thyroid hormone. The ETA guideline separately lists 145650 for pituitary resistance.
  • MeSH concept: thyroid hormone resistance syndrome; the exact current descriptor identifier should be validated directly against the production MeSH release before database ingestion.
  • Common names: generalized thyroid hormone resistance; generalized RTH; resistance to thyroid hormone; thyroid hormone resistance syndrome; Refetoff syndrome; RTHβ/RTH-beta; impaired sensitivity to thyroid hormone due to THRB mutation.
  • ICD: no highly specific, universally used ICD-10 code cleanly captures molecular RTHβ; it is commonly mapped under other specified endocrine/thyroid dysfunction. ICD-11 implementation should likewise be verified locally rather than inferring a molecularly specific code.

Open Targets links THRB with generalized RTH, molecular RTHβ, pituitary RTH, peripheral RTH, and the broader thyroid-hormone-resistance syndrome. These are aggregated disease–gene resources, not individual electronic health records. The Turkish study discussed below is aggregated retrospective patient-level clinical data. (OpenTargets Search: resistance to thyroid hormone-THRB)

2. Etiology, risk, and protective factors

Primary cause

The principal cause is a germline heterozygous pathogenic variant in THRB, encoding nuclear thyroid hormone receptor β. Approximately 75% of cases are familial/autosomal dominant, while the remainder include de novo disease. Mutant TRβ generally exerts a dominant-negative effect over wild-type receptor by reducing ligand binding, preventing corepressor release, impairing coactivator recruitment, or otherwise disrupting transcription at thyroid-hormone-response elements. (persani20242024europeanthyroid pages 9-10, buyukyılmaz2024clinicalcharacteristicsand pages 1-1)

About 10–15% of clinically convincing RTHβ phenotypes lack a detectable coding THRB variant. Proposed explanations include somatic mosaicism and deep intronic or other regulatory defects; this group should not automatically be assumed to have RTHβ until assay interference and alternative diagnoses are rigorously excluded. (persani20242024europeanthyroid pages 9-10, buyukyılmaz2024clinicalcharacteristicsand pages 3-3, belal20247684resistanceto pages 1-2)

Risk and protective factors

  • Genetic risk: an affected parent, a de novo pathogenic THRB allele, or parental mosaicism. No established common susceptibility locus is used clinically.
  • Family history: confers an approximately 50% transmission probability for a heterozygous affected individual, subject to variant interpretation and mosaicism.
  • Environmental, infectious, occupational, dietary, smoking, alcohol, or lifestyle causes: none is established as a cause of Mendelian RTHβ.
  • Protective alleles or environmental protective factors: none validated.
  • Gene–environment interaction: not established for disease occurrence. Iodine exposure, intercurrent thyroid autoimmunity, pregnancy, medication, and thyroid ablation can alter hormone burden and clinical expression without causing the inherited receptor defect.
  • Epigenetic causation: no validated disease-defining methylation or chromatin signature.

3. Phenotypes

Clinical expression is highly variable within and between families and is not reliably predicted by serum hormone concentration alone. Most manifestations can begin in childhood, while nodules, arrhythmia, metabolic complications, and cardiovascular events become more relevant during adulthood. The disorder is generally chronic and lifelong rather than episodic.

Major phenotype groups and suggested HPO terms

Phenotype Type and characteristics Frequency/evidence Suggested HPO annotation
Elevated T4/T3 with non-suppressed TSH Laboratory hallmark; persistent unless modified by treatment or another thyroid disorder Defining pattern Abnormal circulating thyroxine concentration, abnormal circulating triiodothyronine concentration, abnormal TSH level; validate exact HPO IDs in the current release
Goiter Sign; diffuse initially, potentially nodular; variable severity 56% of variant-positive children in the 2024 Turkish cohort HP:0000853, Goiter
Thyroid nodules Structural manifestation, mainly adult surveillance concern 7 adults in the Turkish cohort HP:0100646, Thyroid nodule
Tachycardia/palpitations Cardiovascular sign/symptom; reflects excess T3 action in TRα-predominant myocardium Common qualitative feature; exact universal frequency unavailable HP:0001649, Tachycardia; palpitations term
Atrial fibrillation/heart failure Adult complication; potentially severe Increased-risk signal in contemporary clinical evidence, but absolute penetrance is unavailable HP:0005110, Atrial fibrillation; HP:0001635, Congestive heart failure
ADHD, attention or learning difficulty Behavioral/neurodevelopmental; usually recognized in childhood One child had attention-deficit disorder and learning disability in the Turkish cohort; broader association recognized by ETA HP:0007018, Attention deficit hyperactivity disorder; HP:0001328, Specific learning disability
Anxiety and sleep disturbance Symptoms; variable and potentially fluctuating Qualitative guideline association HP:0000739, Anxiety; sleep-abnormality term
Hearing impairment Sensory sign; developmental or later recognized Qualitative human association; strong mechanistic mouse support HP:0000365, Hearing impairment
Impaired color vision/macular disease Ophthalmic manifestation; color perception can be altered in heterozygous RTHβ; selected splice variants cause a distinct macular dystrophy phenotype Rare/variant-specific HP:0000551, Abnormality of color vision; macular dystrophy term
Dyslipidemia and hepatic steatosis Laboratory/metabolic manifestations reflecting hepatic TRβ resistance Qualitative guideline association HP:0003124, Hypercholesterolemia; HP:0001397, Hepatic steatosis
Reduced bone density Potential chronic complication of hormone excess/tissue-selective action Frequency uncertain; surveillance recommended HP:0000938, Osteopenia
Thyroid autoimmunity Comorbidity rather than the receptor defect itself 23% antibody positivity in the Turkish variant-positive group, reported only in females Autoimmune thyroiditis/thyroid-antibody HPO concepts

The December 2024 Turkish multicenter study examined 50 suspected/familial cases and molecularly confirmed RTHβ in 30 people from eight families. Its abstract reports: “Although most patients with RTHβ were asymptomatic, seven patients exhibited various symptoms.” It found eight heterozygous pathogenic/likely pathogenic missense variants, including three novel variants; 56% of affected children had goiter, seven adults had nodules, and two adults had papillary thyroid cancer. These cancer observations are important for surveillance but do not establish a population-level cancer penetrance from this small, selected cohort. DOI 10.4274/jcrpe.galenos.2024.2024-8-14, published December 2024. (buyukyılmaz2024clinicalcharacteristicsand pages 1-1, buyukyılmaz2024clinicalcharacteristicsand pages 2-3, buyukyılmaz2024clinicalcharacteristicsand pages 3-3)

Quality of life

Palpitations, anxiety, sleep problems, hearing impairment, goiter, and neurocognitive symptoms can impair school, work, and social functioning. However, no validated RTHβ-specific patient-reported outcome instrument, EQ-5D norm, or robust SF-36 cohort estimate was identified. QoL effects should therefore be recorded at the individual-patient level rather than assigned a population percentage.

4. Genetic and molecular information

Causal gene and protein

  • Gene: THRB, thyroid hormone receptor beta.
  • HGNC: HGNC:11799.
  • Ensembl: ENSG00000151090.
  • Protein: nuclear thyroid hormone receptor β; major isoforms TRβ1 and TRβ2.
  • Origin: ordinarily germline; postzygotic/somatic mosaicism is a proposed explanation for some variant-negative cases. This is not a cancer-associated somatic disorder.

Pathogenic variants cluster predominantly in the ligand-binding domain and are commonly missense substitutions. Insertions, deletions, frameshifts, and truncating alleles can occur and may produce more severe receptor dysfunction. The Turkish cohort's eight variants were all heterozygous missense changes; because the retrieved evidence did not expose every HGVS expression and ClinVar accession, these should be imported directly from ClinVar/the primary article rather than reconstructed. (buyukyılmaz2024clinicalcharacteristicsand pages 1-1, buyukyılmaz2024clinicalcharacteristicsand pages 2-3)

Functional consequence and classification

Disease-causing missense alleles are generally loss-of-function at the mutant receptor level but produce dominant-negative gain of interference at the cellular level. A receptor may retain DNA binding while failing to respond appropriately to T3, thereby maintaining corepressor complexes or failing to recruit coactivators and suppressing normal-receptor signaling. (persani20242024europeanthyroid pages 9-10)

For clinical reporting, each variant requires ACMG/AMP classification using segregation, population frequency, functional evidence, location/domain, computational evidence, and prior observations. Pathogenic RTHβ variants are expected to be rare or absent from gnomAD, but no single allele-frequency value applies to the disease. VUS findings must not be treated as diagnostic without segregation or functional support.

Modifiers, epigenetics, and chromosomes

Marked intrafamilial variability implies modifiers, including receptor-isoform distribution, hormone transporters, deiodinases, coregulators, age, and coincident thyroid disease. No specific modifier gene is validated for routine prognostication. No recurrent aneuploidy, translocation, inversion, methylation defect, or chromosomal syndrome defines RTHβ. CMA, karyotyping, and FISH are therefore not first-line tests.

5. Environmental information

RTHβ is not caused by toxin, radiation, pollution, occupation, lifestyle, or infection. Exogenous levothyroxine, liothyronine, amiodarone, biotin-related assay artifacts, antithyroid therapy, iodine status, and thyroid surgery can confound diagnosis or amplify manifestations but do not create the germline disorder. A 2024 case illustrates prolonged misclassification as hypothyroidism and escalation of levothyroxine despite elevated FT4/FT3 and non-suppressed TSH. DOI 10.1210/jendso/bvae163.2063, October 2024. (belal20247684resistanceto pages 1-2)

6. Mechanism and pathophysiology

Causal chain

  1. Upstream trigger: heterozygous pathogenic THRB variant.
  2. Protein defect: altered TRβ ligand binding or transcriptional-coregulator exchange.
  3. Cellular effect: mutant receptor occupies or perturbs thyroid-hormone-response-element complexes and inhibits wild-type signaling.
  4. Central endocrine consequence: pituitary/hypothalamic resistance weakens T3-mediated negative feedback.
  5. Biochemical compensation: TSH remains inappropriately normal or rises, stimulating thyroid growth and increased T4/T3 synthesis.
  6. Tissue-selective consequences: TRβ-rich tissues remain relatively resistant, while TRα-rich heart, skeletal muscle, brain, and bone are exposed to high circulating hormone and may become hyperthyroid.
  7. Clinical outcome: mixed goitrous, metabolic, neurobehavioral, sensory, skeletal, and cardiovascular phenotypes. (persani20242024europeanthyroid pages 9-10)

Pathways and ontology suggestions

  • Canonical pathway: nuclear-receptor-mediated thyroid hormone signaling and transcriptional regulation.
  • Noncanonical signaling: TRs can influence PI3K–AKT and MAPK–ERK signaling, but their contribution to individual human RTHβ phenotypes remains incompletely resolved.
  • Suggested GO biological processes: thyroid hormone receptor signaling pathway; cellular response to thyroid hormone stimulus; regulation of transcription by RNA polymerase II; negative regulation of thyroid-stimulating hormone secretion; sensory perception of sound; cone photoreceptor differentiation; lipid metabolic process.
  • Suggested GO cellular components: GO:0005634 nucleus, chromatin, transcription-regulator complex.
  • Suggested molecular functions: nuclear thyroid hormone receptor activity; ligand-activated transcription-factor activity; DNA-binding transcription-factor activity.
  • Suggested cell types: pituitary thyrotroph (CL:0000476), hepatocyte (CL:0000182), cardiomyocyte (CL:0000746), retinal cone photoreceptor (CL:0000573), cochlear sensory hair cell, thyroid follicular cell, neuron, and osteoblast. Exact CL mappings should be version-validated.

Metabolic, immune, and tissue effects

Hepatic TRβ resistance can contribute to dyslipidemia and increased liver fat. Cardiac injury is principally downstream of chronic high hormone exposure in relatively TRα-sensitive myocardium, manifesting as tachyarrhythmia or failure rather than a primary inflammatory cardiomyopathy. Autoimmune thyroid disease may coexist, but autoimmunity is not the primary mechanism. No established disease-specific transcriptomic, proteomic, metabolomic, lipidomic, single-cell, spatial-transcriptomic, or multi-omic diagnostic signature currently exists. (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 9-10)

7. Anatomical structures affected

  • Primary endocrine axis: hypothalamus, pituitary, and thyroid gland.
  • TRβ-rich targets: liver, kidney, cochlea, and retina.
  • Secondary systems: cardiovascular system, CNS/behavioral circuits, skeleton, skeletal muscle, and metabolic tissues.
  • Suggested UBERON terms: thyroid gland (UBERON:0002046), pituitary gland (UBERON:0000007), hypothalamus (UBERON:0001898), liver (UBERON:0002107), kidney (UBERON:0002113), heart (UBERON:0000948), retina (UBERON:0000966), and cochlea (UBERON:0001844).
  • Subcellular localization: primarily nuclear/chromatin-associated receptor complexes; noncanonical cytoplasmic signaling is also biologically plausible.
  • Lateralization: not characteristic; systemic and generally bilateral sensory involvement is expected.

The expression statement in one 2024 case abstract uses “TSH receptor beta/alpha”; biologically, this should be interpreted as thyroid hormone receptor β/α, not the TSH receptor. (belal20247684resistanceto pages 1-2)

8. Temporal development

The molecular defect is congenital and lifelong. Biochemical abnormalities may be evident neonatally or discovered incidentally in childhood/adulthood. Goiter and neurodevelopmental manifestations often emerge during childhood; nodular thyroid disease, hepatic fat, dyslipidemia, arrhythmia, and cardiovascular complications may accumulate with age. There is no accepted stage system. Course and severity are variable rather than predictably progressive, and spontaneous molecular remission is not expected. Pregnancy is a critical period because fetal genotype determines whether maternal high thyroid hormone levels are compensatory or excessive for the fetus. (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 3-5)

9. Inheritance and population

Reported prevalence is approximately 1 in 18,750–40,000, equivalent to roughly 2.5–5.3 per 100,000. Reliable annual incidence estimates are unavailable. RTHβ affects all sexes and ancestries; no consistent sex ratio, geographic endemicity, or broadly applicable founder effect is established. (buyukyılmaz2024clinicalcharacteristicsand pages 1-1, belal20247684resistanceto pages 1-2)

Inheritance is usually autosomal dominant, with variable expressivity and clinically incomplete recognition. Biochemical penetrance is generally high for established dominant-negative variants, but clinical penetrance is variable. Anticipation is not recognized. Germline/parental mosaicism is possible but not quantified. Consanguinity is not a characteristic risk factor for dominant RTHβ, and population carrier-frequency estimates are not robust enough for general screening.

10. Diagnostics

Clinical biochemical workflow

  1. Confirm elevated FT4/FT3 with non-suppressed TSH on a repeat sample.
  2. Review medications and supplements, especially levothyroxine/liothyronine, amiodarone, heparin-related artifacts, and high-dose biotin.
  3. Exclude analytical interference using another assay platform, dilution/blocking studies, equilibrium dialysis or ultrafiltration where needed; assess binding-protein abnormalities.
  4. Evaluate family thyroid-function tests. Similar biochemical results in a first-degree relative strongly support inherited RTH.
  5. Exclude TSH-secreting pituitary tumor (TSHoma) using clinical context, pituitary hormones/α-subunit where informative, sex-hormone-binding globulin, pituitary MRI, and specialist dynamic testing when uncertainty remains.
  6. Sequence THRB and test segregation. The ETA recommends THRB sequencing when genuinely elevated thyroid hormones coexist with non-suppressed TSH. (belal20247684resistanceto pages 1-2, persani20242024europeanthyroid pages 2-3)

In the Turkish suspected cohort, one of 20 people without a THRB variant was found to have a TSHoma, demonstrating why a negative genetic test does not itself prove “non-THRB RTH.” (buyukyılmaz2024clinicalcharacteristicsand pages 2-3)

Genetic testing strategy

  • First line: sequence THRB coding exons and splice boundaries, with deletion/duplication analysis if the platform does not provide it.
  • Panel: a discordant-thyroid-function/thyroid-hormone-action panel may include THRB, THRA, SLC16A2, SECISBP2, DIO1/DIO2-related candidates, binding-protein genes, and genes relevant to familial dysalbuminemic hyperthyroxinemia, tailored to the biochemical phenotype.
  • WES/WGS: appropriate when targeted testing is negative and the phenotype remains convincing. WGS is better suited to deep intronic/regulatory and structural variants; mosaic-aware analysis may be needed.
  • RNA sequencing: potentially useful to prove abnormal splicing but not routine.
  • CMA, karyotype, FISH, mitochondrial, and repeat-expansion testing: not routinely indicated.

Imaging and monitoring

Thyroid ultrasound evaluates goiter and nodules. In adults—especially after age 30 or when symptomatic—assess blood pressure, ECG, and, when indicated, echocardiography and cardiac biomarkers. Check fasting lipids/glucose and adult bone density. In children, monitor growth, development, hearing, cognition, and ADHD symptoms. (persani20242024europeanthyroid pages 3-5, persani20242024europeanthyroid pages 2-3)

Screening

RTHβ is not part of routine population or newborn genetic screening. Newborn TSH/T4 screening may identify unusual profiles but is not optimized for RTHβ. Cascade biochemical and variant testing of first-degree relatives is recommended after identifying a familial pathogenic variant. Prenatal diagnosis and PGT-M are technically possible following counseling.

11. Outcome and prognosis

Many affected people remain asymptomatic or mildly symptomatic and live independently. Nevertheless, contemporary guideline synthesis associates RTHβ with greater risks of atrial fibrillation, myocardial infarction, heart failure, and earlier mortality, supporting proactive cardiovascular surveillance. No reliable disease-specific 5-year/10-year survival percentage or treated-versus-untreated life-expectancy estimate is available in the retrieved evidence. (persani20242024europeanthyroid pages 9-10)

Potential morbidity includes persistent goiter/nodules, avoidable thyroidectomy after misdiagnosis, arrhythmia, cardiac failure, dyslipidemia, liver fat, low bone density, hearing/vision abnormalities, and educational or behavioral impairment. Prognosis is influenced by genotype, degree of hormone elevation, age, cardiovascular phenotype, thyroid structural disease, and—critically—iatrogenic treatment. Genotype correlates with FT4, resting energy expenditure, and LDL cholesterol, but individual prediction remains limited. (persani20242024europeanthyroid pages 10-11)

12. Treatment and current implementation

General principle

Treatment is phenotype-directed, not laboratory-normalization-directed. An asymptomatic patient with compensated high thyroid hormones generally does not require therapy. Routine antithyroid drugs, radioiodine, or thyroidectomy can destroy compensation and create difficult-to-treat hypothyroidism; the ETA recommends avoiding these approaches absent compelling comorbidity. (buyukyılmaz2024clinicalcharacteristicsand pages 2-3, persani20242024europeanthyroid pages 3-5)

Interventions

  • Observation and surveillance: first-line for asymptomatic/mild disease.
  • Beta-blocker: for tachycardia, tremor, or palpitations; suggested NCIt concept: beta-adrenergic blocking-agent therapy.
  • TRIAC/tiratricol (3,5,3′-triiodothyroacetic acid): a thyroid-hormone analogue with relatively strong pituitary action that lowers TSH and circulating T4/T3. The ETA reports 1.4–2.8 mg two or three times daily, titrated to symptoms and FT4, and recommends expert-center supervision. It can be combined with beta-blockade; selected severe cardiomyopathy cases have used antithyroid medication plus TRIAC to control hormone production without allowing marked TSH-driven goiter. (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 3-5)
  • Supraphysiologic intermittent liothyronine: alternate-day T3 has reduced goiter and helped selected ADHD phenotypes in case-based experience. It is not standardized therapy and requires specialist monitoring. (persani20242024europeanthyroid pages 9-10, belal20247684resistanceto pages 1-2)
  • Antithyroid drugs/ablation/surgery: reserve for exceptional, severe situations or independent thyroid pathology such as suspicious cancer; replacement afterward can be challenging.
  • ADHD or psychiatric therapy: treat according to standard clinical criteria while accounting for cardiovascular risk.
  • Rehabilitation/support: educational accommodations, audiology support, and psychological care as indicated.

No approved gene therapy, CRISPR therapy, ASO/siRNA therapy, cell therapy, immunotherapy, or RTHβ-specific pharmacogenomic guideline exists. Evidence for TRIAC and intermittent T3 is largely observational/case-based, not derived from large randomized RTHβ trials.

Pregnancy

All affected pregnancies warrant joint endocrine–maternal-fetal-medicine care. Maternal RTHβ has been associated with miscarriage and small-for-gestational-age birth. Monitor fetal growth and heart rate; fetal tachycardia or growth restriction may justify carefully selected maternal antithyroid treatment. Management must consider whether the fetus inherited RTHβ: hormone levels compensatory for an affected mother/fetus can be excessive for an unaffected fetus. (persani20242024europeanthyroid pages 10-11, persani20242024europeanthyroid pages 3-5)

Trials and registries

Current real-world research is primarily observational:

  • NCT06307990, Understanding, Diagnosis and Monitoring of Thyroid Hormone Action Defects: recruiting, target 150, Istituto Auxologico Italiano; ClinicalTrials.gov.
  • NCT06566066, Register for Patients With Thyroid Hormone Resistance: recruiting, target 200, Charité Berlin; ClinicalTrials.gov.
  • NCT00001159, Natural History of Thyroid Function Disorders: recruiting NIH observational platform, target 2,500; ClinicalTrials.gov.

No active late-phase disease-modifying RTHβ interventional trial was identified. Trials of tiratricol in MCT8 deficiency or resmetirom in steatotic liver disease should not be misclassified as RTHβ trials.

13. Prevention

Primary prevention of a de novo or inherited receptor variant by lifestyle or vaccination is not possible. Applicable measures are:

  • Genetic counseling: autosomal-dominant recurrence risk, variable expressivity, prenatal diagnosis, and PGT-M.
  • Secondary prevention: cascade testing, early recognition of discordant thyroid tests, and avoiding misdiagnosis as Graves disease, hypothyroidism, or TSHoma.
  • Tertiary prevention: cardiac surveillance, thyroid examination/ultrasound, metabolic and bone monitoring, hearing and neurodevelopmental assessment, and avoidance of unnecessary ablation.
  • Public-health prophylaxis, vaccination, sanitation, environmental remediation, and preventive medication: not applicable.

14. Other species and natural disease

No well-established, clinically important naturally occurring companion-animal or wildlife counterpart of human THRB-associated generalized RTH was identified. There is no zoonotic potential or cross-species transmission because the condition is genetic. Orthologues include mouse Thrb and corresponding vertebrate THRB genes; mechanisms of receptor-mediated transcription and feedback are evolutionarily conserved. Before assigning OMIA, NCBI Gene, or VBO identifiers, they should be verified directly in the relevant live database.

15. Model organisms

Mouse models

Available systems include global Thrb knockout, DNA-binding-deficient TRβGS knock-in, and dominant-negative ligand-binding-domain knock-in models such as ThrbPV. These permit separation of receptor absence, impaired canonical DNA binding, and dominant-negative mutant-receptor effects.

A November 2024 comparative phenotyping preprint found that pituitary–thyroid negative feedback requires TRβ DNA binding; both TRβKO and TRβGS mice had severe hearing loss, while retinal thickness, visual acuity, cone maturation, and opsin expression showed TRβ-dependent abnormalities. It also suggested roles for noncanonical TRβ signaling in liver triglycerides and glucose control. DOI 10.1101/2023.11.26.568063. (hones2024comparativephenotypingof pages 5-9)

Recapitulation and limitations

These mice reproduce central resistance, sensory-system defects, and selected metabolic manifestations and are useful for dissecting canonical versus noncanonical signaling. Some dominant-negative Thrb models develop thyroid hyperplasia/carcinoma under sustained TSH drive, offering a mechanistic tumor model; however, tumor severity in such homozygous or engineered mice must not be directly translated into human cancer penetrance. Species differences, allele dosage, global versus tissue-specific disruption, and controlled genetic backgrounds limit clinical extrapolation.

Cellular reporter assays remain useful for measuring T3 binding, transcriptional activation, dominant-negative activity, corepressor release, and coactivator recruitment. Patient-derived iPSC/organoid, CRISPR-screen, single-cell, and spatial-transcriptomic models are not yet established routine platforms for RTHβ.

Current expert interpretation and evidence gaps

The 2024 ETA panel's central expert position is that discordant thyroid tests must be verified before genetic diagnosis, and management should target clinically important tissue effects rather than force T4/T3 into reference ranges. This is particularly important because inappropriate treatment is common: 41.7% of historically managed patients in the Turkish series had received interventions before diagnosis, including antithyroid therapy or thyroidectomy. (buyukyılmaz2024clinicalcharacteristicsand pages 2-3, persani20242024europeanthyroid pages 3-5)

Major remaining gaps are prospective natural-history data, standardized phenotype frequencies, validated QoL measures, variant-specific penetrance, controlled RTHβ treatment trials, disease-specific mortality estimates, molecular biomarkers beyond thyroid-function tests and genotype, and human single-cell/multi-omic characterization. The newly recruiting registries are therefore clinically relevant recent developments rather than merely administrative studies.

References

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  2. (persani20242024europeanthyroid pages 9-10): Luca Persani, Patrice Rodien, Carla Moran, W Edward Visser, Stefan Groeneweg, Robin Peeters, Samuel Refetoff, Mark Gurnell, Paolo Beck-Peccoz, and Krishna Chatterjee. 2024 european thyroid association guidelines on diagnosis and management of genetic disorders of thyroid hormone transport, metabolism and action. Jul 2024. URL: https://doi.org/10.1530/etj-24-0125, doi:10.1530/etj-24-0125. This article has 58 citations and is from a peer-reviewed journal.

  3. (OpenTargets Search: resistance to thyroid hormone-THRB): Open Targets Query (resistance to thyroid hormone-THRB, 5 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.

  4. (persani20242024europeanthyroid pages 2-3): Luca Persani, Patrice Rodien, Carla Moran, W Edward Visser, Stefan Groeneweg, Robin Peeters, Samuel Refetoff, Mark Gurnell, Paolo Beck-Peccoz, and Krishna Chatterjee. 2024 european thyroid association guidelines on diagnosis and management of genetic disorders of thyroid hormone transport, metabolism and action. Jul 2024. URL: https://doi.org/10.1530/etj-24-0125, doi:10.1530/etj-24-0125. This article has 58 citations and is from a peer-reviewed journal.

  5. (buyukyılmaz2024clinicalcharacteristicsand pages 1-1): Gönül Büyükyılmaz, Büşranur Çavdarlı, Serkan Bilge Koca, Keziban Toksoy Adıgüzel, Oya Topaloğlu, Cevdet Aydın, Sema Hepsen, Erman Çakal, Nur Semerci Gündüz, Mehmet Boyraz, Fatih Gürbüz, and Hüseyin Demirbilek. Clinical characteristics and genotype-phenotype correlation in turkish patients with a diagnosis of resistance to thyroid hormone beta. Journal of Clinical Research in Pediatric Endocrinology, 17:191-201, Dec 2024. URL: https://doi.org/10.4274/jcrpe.galenos.2024.2024-8-14, doi:10.4274/jcrpe.galenos.2024.2024-8-14. This article has 0 citations.

  6. (belal20247684resistanceto pages 1-2): H. Belal, A. N. Mukhtar, and J. M. Chehade. 7684 resistance to thyroid hormone beta mistaken as primary hypothyroidism: variable phenotypes and diagnostic dilemmas. Journal of the Endocrine Society, Oct 2024. URL: https://doi.org/10.1210/jendso/bvae163.2063, doi:10.1210/jendso/bvae163.2063. This article has 0 citations and is from a peer-reviewed journal.

  7. (buyukyılmaz2024clinicalcharacteristicsand pages 2-3): Gönül Büyükyılmaz, Büşranur Çavdarlı, Serkan Bilge Koca, Keziban Toksoy Adıgüzel, Oya Topaloğlu, Cevdet Aydın, Sema Hepsen, Erman Çakal, Nur Semerci Gündüz, Mehmet Boyraz, Fatih Gürbüz, and Hüseyin Demirbilek. Clinical characteristics and genotype-phenotype correlation in turkish patients with a diagnosis of resistance to thyroid hormone beta. Journal of Clinical Research in Pediatric Endocrinology, 17:191-201, Dec 2024. URL: https://doi.org/10.4274/jcrpe.galenos.2024.2024-8-14, doi:10.4274/jcrpe.galenos.2024.2024-8-14. This article has 0 citations.

  8. (buyukyılmaz2024clinicalcharacteristicsand pages 3-3): Gönül Büyükyılmaz, Büşranur Çavdarlı, Serkan Bilge Koca, Keziban Toksoy Adıgüzel, Oya Topaloğlu, Cevdet Aydın, Sema Hepsen, Erman Çakal, Nur Semerci Gündüz, Mehmet Boyraz, Fatih Gürbüz, and Hüseyin Demirbilek. Clinical characteristics and genotype-phenotype correlation in turkish patients with a diagnosis of resistance to thyroid hormone beta. Journal of Clinical Research in Pediatric Endocrinology, 17:191-201, Dec 2024. URL: https://doi.org/10.4274/jcrpe.galenos.2024.2024-8-14, doi:10.4274/jcrpe.galenos.2024.2024-8-14. This article has 0 citations.

  9. (persani20242024europeanthyroid pages 3-5): Luca Persani, Patrice Rodien, Carla Moran, W Edward Visser, Stefan Groeneweg, Robin Peeters, Samuel Refetoff, Mark Gurnell, Paolo Beck-Peccoz, and Krishna Chatterjee. 2024 european thyroid association guidelines on diagnosis and management of genetic disorders of thyroid hormone transport, metabolism and action. Jul 2024. URL: https://doi.org/10.1530/etj-24-0125, doi:10.1530/etj-24-0125. This article has 58 citations and is from a peer-reviewed journal.

  10. (hones2024comparativephenotypingof pages 5-9): G. S. Hönes, Daniela Geist, Christina Wenzek, Paul T. Pfluger, T. Müller, J. A. Aguilar-Pimentel, O. Amarie, L. Becker, Natalia Dragano, Lillian Garrett, S. Hölter, B. Rathkolb, J. Rozman, N. Spielmann, Irina Treise, Eckhard Wolf, Wolfgang Wurst, H. Fuchs, V. Gailus-Durner, M. Hrabě de Angelis, Dagmar Führer, and L. C. Moeller. Comparative phenotyping of mice reveals canonical and noncanonical physiological functions of trα and trβ. bioRxiv, Nov 2024. URL: https://doi.org/10.1101/2023.11.26.568063, doi:10.1101/2023.11.26.568063. This article has 8 citations.

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