Huntington disease

Información en español Title

Other Names:

Huntington's chorea; Huntington's disease; HD

Categories:

Congenital and Genetic Diseases; Nervous System Diseases

Summary Summary

Huntington disease (HD) is an inherited condition that causes progressive degeneration of neurons in the brain. Signs and symptoms usually develop between ages 35 to 44 years and may include uncontrolled movements, loss of intellectual abilities, and various emotional and psychiatric problems. People with HD usually live for about 15 to 20 years after the condition begins. It is caused by changes (mutations) in the HTT gene and is inherited in an autosomal dominant manner. Treatment is based on the symptoms present in each person and may include various medications.^[1]^[2]

There is also a less common, early-onset form of HD which begins in childhood or adolescence. For more information on this form, please visit GARD's juvenile Huntington disease Web page.

Last updated: 7/8/2015

Symptoms Symptoms

Huntington disease (HD) is a progressive disorder that causes motor, cognitive, and psychiatric signs and symptoms. On average, most people begin developing features of HD between ages 35 and 44. Signs and symptoms vary by stage and may include:^[3]^[2]

Early stage:

Behavioral disturbances
Clumsiness
Moodiness
Irritability
Paranoia
Apathy
Anxiety
Hallucinations
Abnormal eye movements
Depression
Impaired ability to detect odors

Middle stage:

Dystonia
Involuntary movements
Trouble with balance and walking
Chorea with twisting and writhing motions
Unsteady gait (style of walking)
Slow reaction time
General weakness
Weight loss
Speech difficulties
Stubbornness

Late stage:

Rigidity (continual tension of the muscles)
Bradykinesia (difficulty initiating and continuing movements)
Severe chorea
Serious weight loss
Inability to speak
Inability to walk
Swallowing problems
Inability to care for oneself

There is also a less common, early-onset form of HD which begins in childhood or adolescence. For more information on this form, please visit GARD's juvenile Huntington disease Web page.

Last updated: 7/7/2015

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Abnormality of movement	50%
Abnormality of the voice	50%
Behavioral abnormality	50%
Cerebral cortical atrophy	50%
Developmental regression	50%
EEG abnormality	50%
Hypertonia	50%
Rigidity	7.5%
Abnormality of eye movement	-
Autosomal dominant inheritance	-
Bradykinesia	-
Chorea	-
Dementia	-
Depression	-
Gliosis	-
Hyperreflexia	-
Neuronal loss in central nervous system	-
Personality changes	-

Last updated: 9/1/2016

Cause Cause

Huntington disease (HD) is caused by a change (mutation) in the HTT gene. This gene gives instructions for making a protein called huntingtin. The exact function of this protein is unclear, but it appears to be important to nerve cells (neurons) in the brain.^[1]

The HTT gene mutation that causes HD involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of three DNA building blocks that repeat multiple times in a row. The CAG segment in a normal HTT gene repeats about 10 to 35 times. In people with HD, it may repeat from 36 to over 120 times. People with 36 to 39 CAG repeats (an intermediate size) may or may not develop HD, while people with 40 or more repeats almost always develop HD.^[1]

An increased number of CAG repeats leads to an abnormally long version of the huntingtin protein. The long protein is then cut into smaller, toxic pieces that end up sticking together and accumulating in neurons. This disrupts the function of the neurons, ultimately causing the features of HD.^[1]

Last updated: 7/8/2015

Inheritance Inheritance

Huntington disease (HD) is inherited in an autosomal dominant manner.^[2] This means that having a change (mutation) in only one of the 2 copies of the HTT gene is enough to cause the condition. When a person with HD has children, each child has a 50% (1 in 2) chance to inherit the mutated gene and develop the condition.

Most people with HD have an affected parent. The family history can sometimes appear negative for various reasons even though a parent carries, or carried, a mutation in the HTT gene. In rare cases, HD is caused by a new (de novo) mutation in the HTT gene, in which case the disease occurs for the first time in the affected person and is not inherited from a parent.^[2]

As HD is passed through generations, the size of the mutation in the HTT gene (called a trinucleotide repeat) often increases. A longer repeat in the HTT gene may cause earlier onset of symptoms. This phenomenon is called anticipation.^[1]

Last updated: 10/21/2015

Diagnosis Diagnosis

Yes. Testing of adults at risk for Huntington disease (HD) who have no symptoms of the disease is called predictive testing. Whether to have predictive testing requires careful thought, including pre-test and post-test genetic counseling. This is particularly important because there is currently no cure. Furthermore, predictive testing cannot accurately predict the age a person with an HD mutation will develop symptoms, the severity or type of symptoms they will experience, or the future rate of disease progression. A person may want to have predictive testing because they feel they need to know, or to make personal decisions involving having children, finances, and/or career planning. Other people decide they do not want to know whether they will develop HD.^[2]

Testing is appropriate to consider in symptomatic people of any age in a family with a confirmed diagnosis of HD. However, testing of asymptomatic people younger than age 18 is not considered appropriate. A main reason is that it takes away the choice of whether the person wants to know, while there is no major benefit to knowing at that age.

People who are interested in learning more about genetic testing for HD should speak with a genetics professional.

Last updated: 7/8/2015

A diagnosis of Huntington disease is typically suspected in people with characteristic signs and symptoms of the condition and a family history consistent with autosomal dominant inheritance. The diagnosis can then be confirmed with genetic testing that identifies a specific type of change (mutation) in the HTT gene.^[2]

Last updated: 7/8/2015

Testing Resources

The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
The Division of Neurogenetics at the University of Washington is a tertiary specialty that provides clinical services to adults in the general public as well as training. They have created a booklet entitled, "Huntington Disease: Making an Informed Choice, that can be downloaded at no charge.
Orphanet lists international laboratories offering diagnostic testing for this condition.

Treatment Treatment

Unfortunately, there is currently no cure for Huntington disease (HD). The current goal of treatment is to slow down the course of the disease and help affected people function for as long and as comfortably as possible.^[3]

Current treatment strategies involve the use of various medications to treat specific symptoms such as abnormal movements and behaviors. Depression and suicide are more common among affected people, so caregivers should monitor for associated symptoms and seek help if necessary. As symptoms of the disease worsen, affected people need more assistance, supervision, and care.^[3]

Last updated: 7/8/2015

Management Guidelines

GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

Tetrabenazine (Brand name: Xenazine®) - Manufactured by Lundbeck Inc.
FDA-approved indication: Treatment of chorea associated with Huntington's disease
National Library of Medicine Drug Information Portal

Prognosis Prognosis

Huntington disease (HD) is progressive, eventually leading to disability and death (usually from a coexisting illness or infection). However, the disease affects everyone differently; the age of onset, specific symptoms, and rate of progression varies for each person with HD.

While the symptoms of HD are well-characterized, their progression (especially in the early and middle stages) remains unpredictable. With the approach of late-stage HD, affected people have speech difficulty and weight loss. In the late stage, affected people lose bowel and bladder control.^[4]

The duration of the disease (from onset until death) varies considerably, with an average of approximately 19 years. Most people with HD survive for 10-25 years after the onset of symptoms. The average age at death ranges from 51-57 years, but the range may be broader. In a large study, pneumonia and cardiovascular (heart) disease were the most common primary causes of death.^[5]

The length of the CAG repeat (the type of mutation in the HTT gene responsible for HD) is the most important factor that determines age of onset of HD. However, there is still a lot of variability. Both genetic and environmental factors are thought to play a role on the age of onset in people with a mutation. Inheritance through the father can lead to more repeat expansion and earlier onset through succeeding generations, a phenomenon called anticipation.^[5]

View our Huntington disease Symptoms page for information about the signs and symptoms typical of each stage.

People with HD, family members, and/or caregivers with specific questions about prognosis should speak with their health care provider.

Last updated: 10/21/2015

Do you have updated information on this condition? Let us know.

Research Research

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

ClinicalTrials.gov lists trials that are studying or have studied Huntington disease. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

Patient Registry

The National Research Roster for Huntington Disease Patients and Families (hdRoster) was established in 1979 at Indiana University. Funded by the National Institute of Neurological Disorders and Stroke, a branch of the National Institutes of Health, the Roster computerizes the names of families, including information about the history of HD in the family (family trees) and other related data. This information identifies HD patients and families who are interested in participating in research projects.

Organizations Organizations

Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

CHDI Foundation
350 Seventh Ave, Suite 200
New York, NY 10001
Telephone: 212-239-9300
Fax: 212-239-2101
E-mail: info@chdifoundation.org
Website: http://chdifoundation.org
Hereditary Disease Foundation
3960 Broadway, 6th Floor
New York, NY 10032
Telephone: 212-928-2172
Fax: 212-928-2172
E-mail: cures@hdfoundation.org
Website: http://www.hdfoundation.org
HOPES
Website: http://hopes.stanford.edu
Huntington Society of Canada
151 Frederick St, Suite 400
Kitchner, Ontario, Intl N2H 2M2
Canada
Toll-free: 800-998-7398
Telephone: 519-749-7063
Fax: (519) 749-8965
E-mail: info@huntingtonsociety.ca/
Website: http://www.huntingtonsociety.ca/
Huntington's Disease Society of America
505 Eighth Ave, Suite 902
New York, NY 10018
Toll-free: (800) 345-HDSA (4372)
Telephone: (212) 242-1968
E-mail: hdsainfo@hdsa.org
Website: http://www.hdsa.org/
International Huntington Association
Callunahof 8
Harfsen, Intl 7217 ST
United Kingdom
Telephone: 31-573-431595
E-mail: iha@huntington-assoc.com
Website: http://www.huntington-disease.org
International Parkinson and Movement Disorder Society
555 East Wells Street, Suite 1100
Milwaukee, WI 53202-3823
Telephone: 414-276-2145
Fax: 414-276-3349
E-mail: info@movementdisorders.org
Website: http://www.movementdisorders.org/

Do you know of an organization? Send us your suggestions.

Living With Living With

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Genetics Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by GeneTests, the American College of Medical Genetics, and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Financial Resources

National Organization for Rare Disorders (NORD) has Disease-Specific Assistance Programs designed to help patients with out-of-pocket costs such as monthly insurance premiums or deductibles. In addition, some programs may provide financial assistance for additional expenses related to a patient's diagnosis such as travel to see a specialist.
The Social Security Administration has included this condition in their Compassionate Allowances Initiative. This initiative speeds up the processing of disability claims for applicants with certain medical conditions that cause severe disability. More information about Compassionate Allowances and applying for Social Security disability is available online.

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

Genetics Home Reference (GHR) contains information on Huntington disease. This website is maintained by the National Library of Medicine.
MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
The National Human Genome Research Institute's (NHGRI) website has an information page on this topic. NHGRI is part of the National Institutes of Health and supports research on the structure and function of the human genome and its role in health and disease.
The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss Huntington disease. Click on the link to view a sample search on this topic.

News & Events News & Events

News

GARD Information Navigator
May 10, 2016
Huntington Disease and the Potential of Gene Silencing
October 26, 2015

NCATS Co-Sponsored Conferences

Gordon Research Conferences CAG Triplet Repeat Disorders and the associated Graduate Research Seminar Saturday, June 22, 2013 - Friday, June 28, 2013
Location: Waterville Valley Resort, Waterville Valley, NH
Description: The 2013 Gordon Research Conference on CAG Triplet Repeat Disorders will bring together top scientists from around the world to discuss high-impact, interdisciplinary research on CAG Triplet Repeat Disorders. The objective of the conference is to promote scientific discussion and facilitate interdisciplinary exchange by bringing leading researchers in the field together with a broad range of experts representing; clinicians, diagnosticians, neurobiologists, pathologists, geneticists and molecular biologists.

Contact: Miles Fabian(301) 594-3827fabianm@mail.nih.gov

Co-funding Institute(s): National Institute of Neurological Disorders and Stroke, Office of Rare Diseases Research
Third Genome Dynamics in the Neurosciences Conference Sunday, July 18, 2010 - Thursday, July 22, 2010
Location: The Hilton Metropole, Brighton, England
Description: The goal of this meeting was to integrate basic processes of DNA damage signaling and repair and clinical aspects of neurological and neurodegenerative disease. The program was designed to bring together leading scientists with primary interests in DNA damage signaling with those working in specific related neurodegenerative disease areas as a means for integrating these fields. It was anticipated that this would generate insights into how normal processes of genome maintenance in the brain contribute to the prevention of a wide range of diseases.

Contact: Dr. Danilo A. Tagle, NINDS(301) 496-5745tagled@mninds.nih.gov

Co-funding Institute(s): National Institute of Neurological Disorders and Stroke, Office of Rare Diseases Research
- Agenda ( - 42KB)
- Speakers ( - 47KB)
- Summary ( - 13KB)
2009 Triplet Repeat Disorders Gordon Conference Sunday, May 31, 2009 - Friday, June 5, 2009
Location: Waterville Valley, NH
Description: The top two priorities of this conference were training and the communication of cutting-edge science in the area of CAG triplet repeat disorders. The focus of this conference was on areas of rapid advancement and latest developments. Speakers were selected for their expertise, recent contributions to the field, and ability to provide lively presentations. The structured discussion leaders were instructed to focus on issues that cut across each presentation in a session.

Contact: Dr. Margaret Sutherland, NINDS 301-496-5680

Co-funding Institute(s): National Institute of Neurological Disorders and Stroke
- Agenda ( - 88KB)

GARD Answers GARD Answers

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

My father has Huntington chorea and his body is stiffening up. I would like to know if this means he is going to pass away soon. His side of the family has had this disease. It has not skipped anyone yet. I was young and don't remember what happens. See answer
Resent test results showed 17 repeats from each parent. The social worker suggested that the test might be in error because the number of repeats is the same. Instead of telling the person they did not have HD, she suggested the test was in error. How likely or unlikely is it for the number of repeats to be the same? When one needs a definitive positive or negative, this negative result, being suggested as possibly an error, is heart wrenching, especially for the patient and her family. Is it uncommon for the numbers to be the same? Should she be retested? How common are mistakes in diagnosing HD? The patient lost a parent to HD. See answer
Can a person of any gender, age, or ethnicity have Huntington disease? See answer
I am a personal trainer working with a client who has HD. While I have seen progress with the exercises we are doing, I am looking for more information regarding the types of exercises that are found to be most effective or certain exercises that should be avoided. See answer
What tests will my doctor order to confirm if I have Huntington disease? See answer
A friend of mine has been diagnosed with Huntington disease. No one else in his family has this condition. Is it possible that a chemical exposure could have caused it, such as to vinyl chloride? See answer
I have a family history of Huntington's disease. My mother was diagnosed with it about 5 years ago. I just needed to know some information about where I can get tested. Also, how early can they start treatment if I am diagnosed with it? I'm only 21 years old. I just thought that maybe the sooner they start the better. See answer