Huntington's Disease

Huntington's disease is an inherited brain disorder that gradually affects movement, thinking and mood, usually starting in adulthood between ages 30 and 50.

Last reviewed: October 2026

Huntington's disease (HD) is an inherited condition that causes nerve cells in parts of the brain to gradually break down. It affects three areas of life: movement, thinking (cognition) and emotions/behavior. Over time, the thinking changes amount to a type of dementia.

Most people develop symptoms in adulthood, usually between ages 30 and 50, according to the Huntington's Disease Society of America (HDSA)—often during prime working and family years. A less common juvenile form begins in childhood or adolescence.

How it is inherited

HD is caused by a change in a single gene called HTT (huntingtin), discovered in 1993. The change is an expanded stretch of repeated DNA "letters" known as a CAG repeat.

Each child of a parent with HD has a 50% chance of inheriting the gene change, according to NINDS.
A child who does not inherit it will not develop HD and cannot pass it on.
Fewer than 27 repeats: not at risk.
27 to 35 repeats: unlikely to develop HD, but the number can grow when passed to children.
36 to 39 repeats: may or may not develop symptoms (MedlinePlus Genetics).
40 or more repeats: almost always develop the disorder.

Longer repeats tend to cause earlier onset, and the repeat can lengthen from one generation to the next—a pattern called anticipation.

HD affects an estimated 3 to 7 per 100,000 people of European ancestry and appears less common in some other populations, according to MedlinePlus Genetics.

Symptoms

Symptoms vary from person to person, and thinking or mood changes may appear years before movement problems.

Movement

Involuntary jerking or writhing movements (chorea) of the fingers, feet, face or trunk
Clumsiness, unsteady walking and falls
Trouble with speech and swallowing as the disease progresses
Unintended weight loss, partly from constant movement

Thinking

Difficulty planning, organizing and prioritizing
Slower thinking and trouble shifting from one task to another
Getting "stuck" on a thought or action
Trouble learning new information
Reduced awareness of one's own symptoms—see Anosognosia (Lack of Awareness)

Mood and behavior

Depression (very common), irritability, anxiety and apathy
Impulsive behavior or outbursts
Obsessive-compulsive behaviors

HDSA notes that symptoms usually worsen over 10 to 25 years, eventually affecting the ability to work, drive, walk and talk.

Diagnosis and genetic testing

Doctors diagnose HD through a neurological exam, family history and a blood test that counts CAG repeats in the HTT gene. Testing is used in two different ways:

Diagnostic testing for someone who already has symptoms
Predictive testing for an adult at risk who has no symptoms

Predictive testing is a deeply personal decision with emotional, family, insurance and career implications. HD centers strongly recommend genetic counseling before and after testing. Some people choose to know; others choose not to. Both are valid. See Genetic Testing and APOE4 for more on genetic testing for brain diseases in general.

Treatment

There is no cure yet, and no treatment proven to slow the disease. But many symptoms can be treated:

Chorea: medicines such as tetrabenazine, deutetrabenazine and valbenazine can reduce involuntary movements (NINDS). Some antipsychotic medicines may also help movements and certain psychiatric symptoms.
Depression, anxiety and irritability: antidepressants and other psychiatric treatments, along with counseling.
Speech, swallowing and mobility: speech-language therapy, physical therapy and occupational therapy.
Nutrition: higher-calorie diets and help from a dietitian to counter weight loss.

Treatment plans work best when a team—neurologist, psychiatrist, therapists, social worker—works together. Research is very active, including trials of treatments aimed at lowering production of the huntingtin protein. See Joining a Clinical Trial.

Living with HD and supporting families

Because HD is inherited and long-lasting, it often affects several generations at once. Helpful steps include:

Connect with specialists. HDSA supports Centers of Excellence and a helpline at 800-345-HDSA (4372).
Plan early. Legal, financial and care decisions are easier while the person can take part—see Living Well with Dementia.
Adapt the home for safety as movement problems grow—see Home Safety.
Watch for depression and suicidal thoughts, which are more common in HD. If you or someone you love is in crisis, call or text 988 (Suicide & Crisis Lifeline) in the U.S.
Support caregivers, who may themselves be at risk or caring for more than one family member—see Caregiver Stress and Burnout.
Use communication strategies as speech becomes harder—see Communicating with Someone with Dementia.

Bottom line

Huntington's disease is a genetic brain disorder that changes movement, thinking and mood over many years. While there is no cure yet, treatment can ease many symptoms, and good planning and support make a real difference. If HD runs in your family, a genetic counselor and an HD-experienced doctor are the best first stops for questions about risk and testing.

Sources

Not medical advice. This article is general information, not a diagnosis or treatment plan for any individual. Talk with a doctor about your situation.

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