Overview
Resistance to thyroid hormone alpha (RTHα), also called thyroid hormone receptor alpha resistance or TRα resistance, is a rare genetic condition where the body cannot properly respond to thyroid hormone in certain tissues. Thyroid hormone normally acts like a key that unlocks important processes in your cells — controlling growth, metabolism, heart rate, brain development, and bone formation. In RTHα, the 'lock' (the thyroid hormone receptor alpha, or TRα) is broken due to a mutation in the THRA gene. This means that even when thyroid hormone levels in the blood look normal or near-normal, many tissues in the body act as if they are not getting enough thyroid hormone. Because TRα receptors are found mainly in the heart, brain, bones, and gut, these are the areas most affected. People with RTHα often have a slow heart rate, constipation, intellectual difficulties, delayed bone development, and short stature. Interestingly, thyroid blood tests may appear misleadingly normal, which can make diagnosis very challenging and lead to long delays. Treatment typically involves giving higher-than-normal doses of thyroid hormone (T3 or T4) to try to overcome the resistance in affected tissues. Management is tailored to each person and requires close monitoring by a specialist. While there is no cure, treatment can meaningfully improve symptoms and quality of life. This condition was only first described in humans in 2012, so it is still being studied and understood.
Also known as:
Key symptoms:
Short stature or slow growth in childrenIntellectual disability or learning difficultiesSlow heart rate (bradycardia)ConstipationDelayed bone development and bone ageLow muscle tone (floppy muscles)Fatigue and low energyAnemia (low red blood cell count)Macrocephaly (larger than normal head size)Delayed tooth developmentThick or coarse facial featuresReduced reflexesDifficulty with movement or coordination
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Variable
Can begin at different ages, from infancy through adulthood
FDA & Trial Timeline
1 eventSunnybrook Health Sciences Centre — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha.
1 clinical trialare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha.
Community
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Start the conversation →Latest news about Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha
Disease timeline:
New recruiting trial: CLinical Evaluation of ANtiseptic Skin Preparation in Revision Total Joint Arthroplasty of the Hip and Knee
A new clinical trial is recruiting patients for Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What dose of thyroid hormone do you recommend for my specific mutation, and how will you monitor whether it is working?,How will we know if the treatment is helping without causing harm to other parts of the body?,Should other family members be tested for the THRA mutation?,What developmental therapies or educational supports do you recommend?,Are there any clinical trials or research studies I or my child could participate in?,How often should we have follow-up appointments and what tests will be done at each visit?,Are there any dietary changes or lifestyle adjustments that could help manage symptoms?
Common questions about Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha
What is Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha?
Resistance to thyroid hormone alpha (RTHα), also called thyroid hormone receptor alpha resistance or TRα resistance, is a rare genetic condition where the body cannot properly respond to thyroid hormone in certain tissues. Thyroid hormone normally acts like a key that unlocks important processes in your cells — controlling growth, metabolism, heart rate, brain development, and bone formation. In RTHα, the 'lock' (the thyroid hormone receptor alpha, or TRα) is broken due to a mutation in the THRA gene. This means that even when thyroid hormone levels in the blood look normal or near-normal, man
How is Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha inherited?
Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
Are there clinical trials for Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha?
Yes — 1 recruiting clinical trial is currently listed for Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha?
1 specialists and care centers treating Resistance to thyroid hormone due to a mutation in thyroid hormone receptor alpha are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.