What's Huntington disease?
Huntington disease is an inherited (autosomal dominant) neurodegenerative brain disease that progressively affects movement, thinking, and behaviour, with onset usually in adulthood. It is caused by an expanded CAG repeat in the HTT gene.
| Also indexed as | ORPHA:399, MONDO:0007739 |
|---|---|
| Features mapped | 12 |
| Treatments mapped | 3 |
| Published sources | 17 |
| Last reviewed | 2026-08-04 |
Signs and symptoms
Chorea
Chorea, brief involuntary jerking or writhing movements, is the most common movement-disorder feature of Huntington disease.
Mental deterioration
Progressive decline in thinking, judgment, and memory is a core feature of Huntington disease alongside the movement changes.
Memory impairment
Alongside the movement problems, Huntington disease brings a steady decline in thinking and memory. This progressive cognitive impairment is one of the three core dimensions of the disease, together with the movement disorder and psychiatric symptoms.
Depression
Depression is one of the significant behavioural features of Huntington disease and affects quality of life.
Irritability
Irritability is a common behavioural feature of Huntington disease.
Bradykinesia
Slowness of movement (bradykinesia) can accompany the involuntary movements of Huntington disease, especially as it advances.
Caudate atrophy
Huntington disease destroys nerve cells deep in the brain, especially in the striatum (which includes the caudate). On scans this shows up as shrinkage of the caudate, and the loss of these movement-control circuits drives the chorea and other motor problems.
Involuntary movements
Involuntary movements, including the dance-like writhing of chorea, are a hallmark motor feature of Huntington disease and tend to progress over years.
Apathy
Apathy, a loss of motivation and interest, is one of the behavioral symptoms that can occur in Huntington's disease.
Anxiety
Anxiety is one of the behavioral symptoms recognized as significant in Huntington's disease.
Obsessive-compulsive behavior
Obsessive-compulsive behaviors, repeated unwanted thoughts or rituals, are among the behavioral symptoms that can occur in Huntington's disease.
Psychosis
Psychosis, a loss of contact with reality, is one of the behavioral symptoms that can occur in Huntington's disease.
How it is diagnosed
Huntington disease
Diagnosed using: HTT CAG repeat genetic test.
“The diagnosis is usually confirmed through identification of an increased CAG repeat length in the huntingtin gene in a patient with clinical features of the…”
Huntington disease
Diagnosed using: CAG repeat fragment analysis.
“…fragment analysis has been the first-tier test in genetic diagnosis of…”
Treatment and management
What the research describes, not a recommendation. Treatment decisions belong with your clinician.
This covers treatments that appear in the published research mapped here. Investigational and experimental therapies are not included, so their absence is a boundary of this map, not a sign they do not exist.
Deutetrabenazine
Deutetrabenazine is an oral medicine that reduces chorea in Huntington disease by inhibiting the vesicular monoamine transporter 2 (VMAT2). It treats the symptom, not the underlying disease.
Used to help with: Chorea.
“Deutetrabenazine was recently approved for the treatment of chorea in Huntington's disease (HD) and is the first deuterated medication that has been US Food and Drug Administration (FDA)-approved for therapeutic use.”
Tetrabenazine
Tetrabenazine is the original vesicular monoamine transporter 2 (VMAT2) inhibitor used to reduce chorea in Huntington disease, treating the symptom rather than the disease itself.
Used to help with: Chorea.
“Deutetrabenazine is the first deuterated drug and second drug after tetrabenazine, the classic vesicular monoamine transporter type 2 (VMAT2) inhibitor, to receive approval for the treatment of chorea associated with HD.”
valbenazine
Valbenazine is a vesicular monoamine transporter 2 (VMAT2) inhibitor approved to treat the chorea of Huntington disease.
Used to help with: Chorea.
“Valbenazine is a vesicular monoamine transporter 2 (VMAT2) inhibitor approved for the treatment of tardive dyskinesia and Huntington's…”
What changes how it shows up
Carrying the genetic change is not the whole story. The factors below are described in the research mapped here as changing whether, or how strongly, the condition appears. They modulate how the genotype is expressed; they do not, on their own, cause or cure it.
autosomal dominant inheritance
Huntington disease is passed down in an autosomal dominant pattern, meaning a single copy of the expanded gene from one parent is enough to cause the condition.
Described as modulating: Huntington disease.
“Huntington disease is devastating to patients and their families - with autosomal dominant…”
expanded CAG repeat in HTT
Huntington disease is caused by an expanded, variable-length CAG repeat in the HTT gene, which carries the instructions for the protein huntingtin.
Described as modulating: Huntington disease.
“The disease is caused by an expanded CAG trinucleotide repeat (of variable length) in HTT, the gene that encodes the protein…”
CAG repeat length and age of onset
A longer CAG repeat length is associated with an earlier estimated age when symptoms begin.
Described as modulating: Huntington disease.
“Repeat length negatively correlated with estimated onset age in both…”
pre-symptomatic phase
Huntington disease often has a long phase before symptoms appear.
Described as modulating: Huntington disease.
“…often following a prolonged pre-symptomatic…”
How to read the evidence labels
Where this comes from
This guide is built from 17 published source(s). Every claim above links back to one of them. Click any source ID to read the original on PubMed.
Take it further
Printed, source-linked documents built from this condition's graph — ready to bring to an appointment or attach to a coverage request. Every claim carries its published source, the same as this guide.