Huntington’s disease (HD) is an inherited brain disorder caused by a single faulty gene. Because it is passed on in an autosomal dominant pattern, every child of an affected parent has a 50 percent chance of inheriting it, and nearly everyone who inherits the fully expanded gene will eventually develop symptoms if they live long enough. According to the Huntington’s Disease Society of America (HDSA), roughly 41,000 Americans have symptomatic disease, with an estimated 200,000 more at risk. The disorder produces a triad of movement, cognitive, and psychiatric symptoms that typically worsen over 10 to 25 years. This guide is general education and not a substitute for care from a neurologist or genetic counselor; the disease is serious and deeply personal, and no article can replace individualized medical advice.
The Genetics in Plain Terms
HD is caused by an abnormally expanded CAG trinucleotide repeat in the HTT gene on chromosome 4. Healthy people typically have about 10 to 35 CAG repeats. Anyone with 40 or more will develop the disease if they live long enough; the 36–39 range is incompletely penetrant, meaning some people in that range may not develop obvious symptoms in a normal lifespan. Larger expansions tend to correlate with earlier onset — a relationship called anticipation, in which successive generations may show symptoms at younger ages, particularly when the gene is inherited from the father.
The mutant protein, called huntingtin, accumulates in brain cells and is particularly toxic to medium spiny neurons in the striatum. As NINDS explains, brain imaging can show striatal atrophy years before clinical symptoms appear. Because HD is autosomal dominant, a person needs only one copy of the expanded gene — inherited from either parent — to be affected.
Symptoms Across Three Domains
The most recognizable symptom is chorea — involuntary, dance-like movements that flow from one body part to another. Early on, chorea may be mistaken for fidgetiness or restlessness. As the disease advances, voluntary movements become slow and clumsy, balance worsens, and difficulty swallowing (dysphagia) develops.
Cognitive symptoms often start years before movement problems. People may notice difficulty multitasking, learning new information, planning, and organizing thoughts. This “executive dysfunction” tends to dominate over pure memory loss, which distinguishes HD cognition from Alzheimer’s disease. Insight is often preserved early but can fade over time.
Psychiatric symptoms are sometimes the earliest manifestation. Depression is common — affecting a large share of patients — and substantially raises the risk of suicide, which occurs at rates well above the general population. Irritability, apathy, anxiety, obsessive thinking, and, less often, psychosis can also occur. Because mood and behavioral symptoms can appear before movement changes, they are easy to attribute to something else; taking them seriously and seeking evaluation matters. If you or someone you love is having thoughts of suicide, call or text 988 to reach the 988 Suicide and Crisis Lifeline (available 24/7 in the U.S.), or go to the nearest emergency room.
Average Onset and Progression
Symptoms typically begin between ages 30 and 50, though juvenile-onset HD (before about age 21) and late-onset HD (after 65) both exist. Juvenile cases — roughly 5 to 10 percent — often present differently, with rigidity, slowness, seizures, and rapid cognitive decline rather than prominent chorea.
The disease generally progresses over an average of about 15 to 20 years from symptom onset. Mid-stage problems include falls, choking, weight loss despite normal or increased eating, and growing dependence on caregivers. Late-stage HD brings near-total loss of motor function; death is usually from complications such as pneumonia, problems related to immobility, or injuries from falls, rather than from the disease acting directly. Every person’s course is different, and these figures are averages, not predictions for any individual.
Diagnosis and Genetic Testing
Genetic testing can definitively confirm or exclude HD by counting CAG repeats. The decision to test, however, is far more complicated than the test itself. Predictive testing in people who are at risk but have no symptoms follows a structured protocol that includes genetic counseling, psychological support, and a deliberate waiting period — in part because learning a positive result carries documented risks of depression and suicidal thinking. This is genuinely one of the weightiest medical decisions a person can face, and there is no “right” answer that fits everyone.
Studies suggest only a minority of at-risk people — often cited in the range of roughly 5 to 25 percent, varying by country and era — choose predictive testing. Reasons people test include family planning, financial and career decisions, and resolving uncertainty; reasons people decline include concerns about the emotional impact, worries about insurance or employment, and the fact that there is not yet a cure. Genetic counselors help people think through these implications before, during, and after testing. In the U.S., the Genetic Information Nondiscrimination Act (GINA) offers some protections against genetic discrimination in health insurance and employment, though it does not cover life, disability, or long-term care insurance — another reason to discuss timing with a counselor.
When to seek emergency care: Call 911 or go to the nearest emergency room if a person with HD expresses suicidal thoughts with intent or a plan, has a sudden major change in behavior or alertness, suffers a fall with a head injury, or chokes severely on food or saliva. Suicide risk is meaningfully elevated in HD, and prompt crisis intervention saves lives. For emotional crises that are not immediately life-threatening, 988 provides confidential support by call or text.
Treatment of Symptoms
No therapy has yet been proven to stop or slow HD progression, but several treatments help manage specific symptoms — always under a prescriber’s direction, because dosing and monitoring must be individualized. For chorea, the FDA has approved VMAT2 inhibitors: tetrabenazine, deutetrabenazine, and valbenazine. These can reduce involuntary movements but require careful monitoring, including for depression and mood changes, so they are prescribed and adjusted only by a clinician who knows the patient. Atypical antipsychotics such as olanzapine can address both chorea and certain psychiatric symptoms and are sometimes used off-label. Do not start, stop, or change any of these medications on your own.
Depression is treated with standard antidepressants, commonly SSRIs as a first line, alongside psychotherapy where appropriate. Cognitive-behavioral and supportive therapy can help with mood, especially earlier in the disease. Speech therapy addresses swallowing and communication; physical and occupational therapy help with balance, falls, and daily function. A multidisciplinary team generally provides the best results.
Care Planning and Daily Life
HD demands long-term planning that healthier families can defer. Advance directives, durable powers of attorney, and decisions about feeding support and resuscitation are best discussed while cognition is intact and the person can express their own wishes. Many families work with elder-law attorneys familiar with progressive neurological disease to navigate Medicaid eligibility, special-needs trusts, and long-term-care options.
Caloric needs often rise because chorea burns extra energy; some people need substantially more calories than usual to maintain weight, and soft, calorie-dense foods can be easier to manage than three structured meals. A dietitian and speech therapist can help reduce choking risk as swallowing changes. Our medical conditions overview covers broader caregiving considerations that apply across progressive neurological diseases, and comparing HD with related disorders in our dementia guide can help families sort out overlapping symptoms.
Emerging Therapies and Research
Gene-targeting approaches remain the most closely watched frontier. Antisense oligonucleotides (ASOs) aim to lower production of the harmful huntingtin protein; one such drug, tominersen, showed early promise but did not demonstrate benefit in a phase 3 trial, and research on refined dosing and patient selection has continued. Newer strategies — allele-selective ASOs designed to lower only the mutant huntingtin, RNA interference therapies, and gene-editing approaches — are in active development, and several candidates have advanced in clinical testing. Progress has been uneven and no disease-modifying therapy is approved yet, so treat news of any experimental therapy cautiously and verify its current status with your care team.
Observational research platforms such as Enroll-HD have built some of the largest natural-history datasets in any rare disease, which helps researchers design better trials. At-risk family members and patients can often participate in observational studies without taking any drug, contributing to research while staying connected to expert centers.
When to See a Doctor
Anyone with a family history of HD who notices new movement problems, depression, irritability, or cognitive change should be evaluated by a neurologist. People with no known family history but new chorea also deserve a full workup — a meaningful minority of HD cases involve no known affected parent, sometimes because of unrecognized symptoms in a relative, early death of a parent, or non-paternity.
Specialized HD clinics — the HDSA maintains a list of Centers of Excellence — offer multidisciplinary care including neurology, psychiatry, social work, genetic counseling, and rehabilitation therapies, and can connect patients and families to clinical trials and local support.
Frequently Asked Questions
If my parent has Huntington’s, will I get it?
Each child of an affected parent has a 50 percent chance of inheriting the expanded gene. Because HD is autosomal dominant, anyone who inherits 40 or more CAG repeats will develop the disease if they live a normal lifespan. Predictive testing can resolve the uncertainty but is a major personal decision, typically made with genetic-counseling support. There is no obligation to be tested, and many at-risk people choose not to be.
Can Huntington’s skip a generation?
True skipping is rare. What can look like skipping is usually a parent who died before symptoms appeared, or who carried an intermediate-range repeat that expanded further in a child. Anticipation — earlier and more severe disease in successive generations — is more common when the gene is inherited from the father.
How is Huntington’s different from Parkinson’s?
Parkinson’s disease causes slowness and rigidity from loss of dopamine-producing neurons, while Huntington’s classically causes excess movement (chorea) from striatal damage. Their cognitive and psychiatric features differ, and Huntington’s is a single-gene inherited disorder, whereas most Parkinson’s is not clearly inherited. Our Parkinson’s disease guide covers those distinctions in detail.
Is there a cure for Huntington’s disease?
Not yet. Symptomatic treatments help with chorea, depression, and other psychiatric symptoms but do not change the underlying disease course. Multiple gene-targeting therapies are in clinical trials, and the research community has more tools and datasets than ever before, but any timeline for a disease-modifying treatment remains uncertain.
Where can families find support?
The HDSA offers education, local chapters, support groups, and a network of Centers of Excellence. A genetic counselor, neurologist, and social worker can help coordinate medical care, testing decisions, and long-term planning. For mental-health crises, 988 provides free, confidential support by call or text.
What to Do Next
Anyone confronting HD — whether symptomatic or at risk — benefits from connecting with an HDSA Center of Excellence, where multidisciplinary teams handle the medical, psychiatric, social, and genetic dimensions of the disease. For at-risk individuals, predictive testing should be considered only with structured genetic counseling and support. For symptomatic patients, early connection to specialty care, consideration of observational research, and, where appropriate, clinical trials offer the strongest path forward. The disease is hard, but families navigating it today have access to a community, a research infrastructure, and a therapeutic pipeline that did not exist a generation ago. You do not have to face it alone, and help — medical, emotional, and practical — is available.
Huntington’s disease is an inherited (autosomal dominant) brain disorder from an expanded CAG repeat in the HTT gene; each child of an affected parent has a 50% chance of inheriting it. It causes movement (chorea), cognitive, and psychiatric symptoms, usually starting between ages 30 and 50, and there is no cure yet — treatment manages symptoms, including prescriber-directed VMAT2 inhibitors for chorea. Depression and suicide risk are elevated: if you or someone you know is in crisis, call or text 988 or go to the nearest ER. This is general information, not medical advice; see a neurologist and genetic counselor, and connect with the HDSA for support.
Sources
- NINDS (National Institute of Neurological Disorders and Stroke) — Huntington’s disease
- MedlinePlus Genetics — Huntington disease (HTT gene, CAG repeats, inheritance, prognosis)
- Huntington’s Disease Society of America (HDSA) — overview, prevalence, and Centers of Excellence
- 988 Suicide and Crisis Lifeline (call or text 988)
- FDA prescribing information — tetrabenazine, deutetrabenazine, and valbenazine (VMAT2 inhibitors for chorea)
Research and treatment options evolve; verify current details with your neurologist, a genetic counselor, and the sources above.