Overview
Tremor-ataxia-central hypomyelination syndrome (also sometimes referred to by its gene-based name, POLR3-related leukodystrophy or 4H syndrome in some overlapping classifications) is a rare inherited brain disorder that affects the nervous system. The name describes its three main features: tremor (shaking), ataxia (problems with balance and coordination), and central hypomyelination (a shortage of the protective coating called myelin that surrounds nerve fibers in the brain and spinal cord). Without enough myelin, nerve signals cannot travel properly, leading to a range of neurological problems. The condition typically begins in childhood and slowly gets worse over time. Children may first show signs of delayed motor development, unsteady walking, or involuntary shaking. As the disease progresses, it can also affect speech, swallowing, vision, and thinking skills. Some children may have dental problems or hormonal issues such as delayed puberty. There is currently no cure for this condition. Treatment focuses on managing symptoms and improving quality of life. This includes physical therapy, speech therapy, occupational therapy, and medications to help control tremors or other specific symptoms. A team of specialists is usually needed to provide the best care.
Also known as:
Key symptoms:
Tremor (involuntary shaking, often of the hands or head)Ataxia (poor balance and unsteady, wobbly walking)Delayed motor development (late reaching milestones like walking)Speech difficulties or slurred speechDifficulty swallowingReduced muscle coordinationVision problems, including abnormal eye movementsIntellectual disability or learning difficultiesDental abnormalities (such as delayed tooth development)Hormonal problems, including delayed or absent pubertyMuscle stiffness or spasticityGradual loss of previously gained motor skills
Clinical phenotype terms (41)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Childhood
Begins in childhood, roughly ages 1 to 12
Treatments
No FDA-approved treatments are currently listed for Tremor-ataxia-central hypomyelination syndrome.
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Specialists
View all specialists →No specialists are currently listed for Tremor-ataxia-central hypomyelination syndrome.
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 Tremor-ataxia-central hypomyelination syndrome.
Community
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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.Which specific gene change has been found in my child, and what does that mean for how the disease will progress?,What therapies should we start right away, and how often should they happen?,Are there any clinical trials or research studies we could consider joining?,What signs should prompt us to seek emergency care?,How will we monitor for hormonal or puberty-related problems?,What school or educational accommodations should we request?,Are other family members at risk, and should they be tested?
Common questions about Tremor-ataxia-central hypomyelination syndrome
What is Tremor-ataxia-central hypomyelination syndrome?
Tremor-ataxia-central hypomyelination syndrome (also sometimes referred to by its gene-based name, POLR3-related leukodystrophy or 4H syndrome in some overlapping classifications) is a rare inherited brain disorder that affects the nervous system. The name describes its three main features: tremor (shaking), ataxia (problems with balance and coordination), and central hypomyelination (a shortage of the protective coating called myelin that surrounds nerve fibers in the brain and spinal cord). Without enough myelin, nerve signals cannot travel properly, leading to a range of neurological proble
How is Tremor-ataxia-central hypomyelination syndrome inherited?
Tremor-ataxia-central hypomyelination syndrome follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Tremor-ataxia-central hypomyelination syndrome typically begin?
Typical onset of Tremor-ataxia-central hypomyelination syndrome is childhood. Age of onset can vary across affected individuals.