# data[].attributes.body
- neurological testing
- genetic testing
- diagnostic imaging
- prenatal testing

# data[].attributes.body
- rate of progression differs from person to person
- earlier the symptoms, faster the diseases progress
- between 30-50 or before 20.

# data[].attributes.body
- behavior changes: mood swings, irritable, apathetic, depressed
- uncontrolled and difficult movement: may begin with feet, hands. Tremors and uncontrollable eye movements.
- Physical Change: speech is slurred. Swallowing, eating, and speaking are declined. Insomnia, loss of energy.

# data[].attributes.attachment_link.readable_text
Overview

Huntington's disease is a rare, inherited disease that causes the progressive breakdown (degeneration) of nerve cells in the brain. Huntington's disease has a wide impact on a person's functional abilities and usually results in movement, thinking (cognitive) and psychiatric disorders.

Huntington's disease symptoms can develop at any time, but they often first appear when people are in their 30s or 40s. If the condition develops before age 20, it's called juvenile Huntington's disease. When Huntington's develops early, symptoms are somewhat different and the disease may progress faster.

Medications are available to help manage the symptoms of Huntington's disease. But treatments can't prevent the physical, mental and behavioral decline associated with the condition.

Products & Services

Show more products from Mayo Clinic

Symptoms

Huntington's disease usually causes movement, cognitive and psychiatric disorders with a wide spectrum of signs and symptoms. Which symptoms appear first varies greatly from person to person. Some symptoms appear more dominant or have a greater effect on functional ability, but that can change throughout the course of the disease.

Movement disorders

The movement disorders associated with Huntington's disease can include both involuntary movement problems and impairments in voluntary movements, such as:

Involuntary jerking or writhing movements (chorea)

Muscle problems, such as rigidity or muscle contracture (dystonia)

Slow or unusual eye movements

Impaired gait, posture and balance

Difficulty with speech or swallowing

Impairments in voluntary movements - rather than involuntary movements - may have a greater impact on a person's ability to work, perform daily activities, communicate and remain independent.

Cognitive disorders

Cognitive impairments often associated with Huntington's disease include:

Difficulty organizing, prioritizing or focusing on tasks

Lack of flexibility or the tendency to get stuck on a thought, behavior or action (perseveration)

Lack of impulse control that can result in outbursts, acting without thinking and sexual promiscuity

Lack of awareness of one's own behaviors and abilities

Slowness in processing thoughts or ''finding'' words

Difficulty in learning new information

Psychiatric disorders

The most common psychiatric disorder associated with Huntington's disease is depression. This isn't simply a reaction to receiving a diagnosis of Huntington's disease. Instead, depression appears to occur because of injury to the brain and subsequent changes in brain function. Signs and symptoms may include:

Feelings of irritability, sadness or apathy

Social withdrawal

Insomnia

Fatigue and loss of energy

Frequent thoughts of death, dying or suicide

Other common psychiatric disorders include:

Obsessive-compulsive disorder, a condition marked by recurrent, intrusive thoughts and repetitive behaviors

Mania, which can cause elevated mood, overactivity, impulsive behavior and inflated self-esteem

Bipolar disorder, a condition with alternating episodes of depression and mania

In addition to the above disorders, weight loss is common in people with Huntington's disease, especially as the disease progresses.

Symptoms of juvenile Huntington's disease

The start and progression of Huntington's disease in younger people may be slightly different from that in adults. Problems that often present early in the course of the disease include:

Behavioral changes

Difficulty paying attention

Rapid, significant drop in overall school performance

Behavioral problems

Physical changes

Contracted and rigid muscles that affect gait (especially in young children)

Tremors or slight involuntary movements

Frequent falls or clumsiness

Seizures

When to see a doctor

See your health care provider if you notice changes in your movements, emotional state or mental ability. The signs and symptoms of Huntington's disease can be caused by a number of different conditions. Therefore, it's important to get a prompt, thorough diagnosis.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

Email field is required

Include a valid email address

Learn more about Mayo Clinic's use of data.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Thank you for subscribing!

You'll soon start receiving the latest Mayo Clinic health information you requested in your inbox.

Sorry something went wrong with your subscription

Please, try again in a couple of minutes

Causes

Huntington's disease is caused by an inherited difference in a single gene. Huntington's disease is an autosomal dominant disorder, which means that a person needs only one copy of the nontypical gene to develop the disorder.

With the exception of genes on the sex chromosomes, a person inherits two copies of every gene - one copy from each parent. A parent with a nontypical gene could pass along the nontypical copy of the gene or the healthy copy. Each child in the family, therefore, has a 50% chance of inheriting the gene that causes the genetic disorder.

Complications

After Huntington's disease starts, a person's functional abilities gradually worsen over time. The rate of disease progression and duration varies. The time from the first symptoms to death is often about 10 to 30 years. Juvenile Huntington's disease usually results in death within 10 years after symptoms develop.

The clinical depression associated with Huntington's disease may increase the risk of suicide. Some research suggests that the greatest risk of suicide occurs before a diagnosis is made and in the middle stages of the disease when a person starts to lose independence.

Eventually, a person with Huntington's disease requires help with all activities of daily living and care. Late in the disease, the person will likely be confined to a bed and unable to speak. Someone with Huntington's disease is generally able to understand language and has an awareness of family and friends, though some won't recognize family members.

Common causes of death include:

Pneumonia or other infections

Injuries related to falls

Complications related to the inability to swallow

Prevention

People with a known family history of Huntington's disease are understandably concerned about whether they may pass the Huntington gene on to their children. These people may consider genetic testing and family planning options.

If an at-risk parent is considering genetic testing, it can be helpful to meet with a genetic counselor. A genetic counselor will discuss the potential risks of a positive test result, which would indicate that the parent will develop the disease. Also, couples will need to make additional choices about whether to have children or to consider alternatives, such as prenatal testing for the gene or in vitro fertilization with donor sperm or eggs.

Another option for couples is in vitro fertilization and preimplantation genetic diagnosis. In this process, eggs are removed from the ovaries and fertilized with the father's sperm in a laboratory. The embryos are tested for presence of the Huntington gene, and only those testing negative for the Huntington gene are implanted in the mother's uterus.

# data[].attributes.attachment_link.title
Huntington's disease - Symptoms and causes

# data[].attributes.attachment_link.description
This condition causes a progressive breakdown of nerve cells in the brain. Find out about what signs to watch for and how treatments may help.

# data[].attributes.body
It is passed down through the parent as a mutated gene. It is from Chromosome #4.

# data[].attributes.body
Inherited disease that causes the dying off of nerve cells in certain parts of the brain

# data[].attributes.attachment_link.readable_text
Huntington's disease (HD) is a fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain. It deteriorates a person's physical and mental abilities during their prime working years and has no cure. HD is known as the quintessential family disease because every child of a parent with HD has a 50/50 chance of carrying the faulty gene. Today, there are approximately 30,000 symptomatic Americans and more than 200,000 at-risk of inheriting the disease.

Many describe the symptoms of HD as having ALS, Parkinson's and Alzheimer's - simultaneously.

Symptoms usually appear between the ages of 30 to 50, and worsen over a 10 to 25 year period. Ultimately, the weakened individual succumbs to pneumonia, heart failure or other complications. Everyone has the gene that causes HD, but only those that inherit the expansion of the gene will develop HD and perhaps pass it on to each of their children. Every person who inherits the expanded HD gene will eventually develop the disease. Over time, HD affects the individual's ability to reason, walk and speak.

Symptoms Include:

Personality changes, mood swings & depression

Forgetfulness & impaired judgment

Unsteady gait & involuntary movements (chorea)

Slurred speech, difficulty in swallowing & significant weight loss

Stages of HD

Although symptoms of HD vary from person to person, even within the same family, the progression of the disease can be roughly divided into three stages.

Early stage HD usually includes subtle changes in coordination, perhaps some involuntary movements (chorea), difficulty thinking through problems and often a depressed or irritable mood. Medications are often effective in treating depression or other emotional problems. The effects of the disease may make the person less able to work at their customary level and less functional in their regular activities at home.

In the middle stage, the movement disorder may become more of a problem. Medication for chorea may be considered to provide relief from involuntary movements. Occupational and physical therapists may be needed to help maintain control of voluntary movements and to deal with changes in thinking and reasoning abilities. Diminished speech and difficulty swallowing may require help from a speech language pathologist. Ordinary activities will become harder to do.

In the late stage, the person with HD is totally dependent on others for their care. Choking becomes a major concern. Chorea may be severe or it may cease. At this stage, the person with HD can no longer walk and will be unable to speak. However, he or she is generally still able to comprehend language and retains an awareness of family and friends. When a person with HD dies, it is typically from complications of the disease, such as choking or infection and not from the disease itself.

In all stages of HD, weight loss can be an important complication that can correspond with worsening symptoms and should be countered by adjusting the diet and maintaining appetite.

The Scope of HD

Approximately 30,000 Americans have HD, but the devastating effects of the disease touch many more. Within a family, multiple generations may have inherited the disease. Those at-risk may experience tremendous stress from the uncertainty and sense of responsibility. In the community, lack of knowledge about HD may keep friends and neighbors from offering social and emotional support to the family, fostering unnecessary isolation. The Huntington's Disease Society of America has a nationwide network that provides support and referrals for individuals with HD and their families.

HD affects both sexes and all races and ethnic groups around the world.

Who Is At Risk

Every child of a parent with HD has a 50/50 chance of inheriting the expanded gene that causes the disease. If the child has not inherited this expanded gene, he or she will never develop the disease and cannot pass it on to their children.

Genetic Testing & Family Planning

People at-risk for the disease face a difficult choice about genetic testing for HD, given the current absence of an effective treatment or cure. Many people see no benefit in knowing that they will someday develop the disease. Others want an end to uncertainty so that they can make informed choices about the future. The decision whether to test or not is intensely personal and there is no "right" answer.

The Huntington's Disease Society of America recommends that at risk individuals who are considering genetic testing do so at a genetic testing center that follows the HDSA guidelines. Testing procedures at these centers involves sessions with professionals who are knowledgeable about HD and the local services available. It may take several weeks to receive the results once the genetic test is complete.

Genetic testing for children is typically prohibited before the age of 18, as the child may not understand the full implications of testing and may be vulnerable to pressure from others. However, a child under the age of 18 may be tested to confirm a diagnosis of juvenile onset HD after a thorough neurological exam.

Prenatal Testing

For families wishing to have a child who does not have the gene that causes HD, there are a few options. Pre-genetic diagnostic (PGD) testing can be used with In Vitro Fertilization (IVF) to make sure that any fertilized egg implanted does not have the abnormal gene. This can be done without informing the at-risk patient whether or not they have the gene that causes HD. If a woman is already pregnant, she can receive testing for the fetus with a chorionic villus biopsy at 10-11 weeks or via amniocentesis at 14-18 weeks. CLICK HERE TO FIND TESTING CENTERS NEAR YOU.

JHD Overview

In approximately 10% of cases, HD affects children or adolescents. The symptoms of Juvenile HD (JHD) are somewhat different than adult onset HD and may include stiff or awkward walking, increased clumsiness or changes in speech. The ability to learn new information may decline and the child may lose skills they previous had. JHD typically progresses more rapidly than adult onset HD. CLICK HERE FOR MORE INFORMATION

An End To HD?

In 1993, researchers identified the gene that causes HD. Since then, research has moved quickly towards developing treatments and, ultimately, a cure. HDSA supports the goals of clinical and basic research at leading research facilities globally. Clinical and observational trials are an important way you can help to sustain the momentum of HD research and move potential new therapies through the approval process. Visit the Research section of the HDSA website for more information and to find a trial in your area. There are opportunities for all HD family members - gene positive, at-risk, gene negative, and caregivers - to participate.

Where to find help?

With HDSA, no one fights alone. HDSA has developed a nationwide network that includes Chapters, Affiliates, HDSA Centers of Excellence, Support Groups and Social Workers that are ready to assist you with resources in your area.

# data[].attributes.attachment_link.description
Huntington's disease (HD) is a fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain. It deteriorates a person's physical and mental abilities during their prime working years and has no cure. HD is known as the quintessential family disease because every child of a parent with HD has a 50/50 chance of carrying the faulty gene.

# data[].attributes.body
There are treatments to help control the side effects, but as of right now there are no treatments for the disease itself. The disease is also not preventable.

# data[].attributes.attachment_link.readable_text
What is Huntington's disease? How is HD diagnosed? Prenatal testing What treatments are available for HD? Where can I get more information?
Glossary
What kind of care do individuals with HD need?
What community resources are available?
What research is being done?
What is predictive testing and how is it done?
How does HD affect the brain?
How is HD Inherited?
What are the major effects of the disease?
At what age does HD appear?
What is Huntington's disease?

Huntington's disease is an inherited disease that causes the progressive dying off, or degeneration, of nerve cells in certain parts of the brain. American physician George Huntington wrote the first thorough description of Huntington's disease (HD) in 1872, calling it "hereditary chorea" to underscore some of its key features. Chorea ¹ is derived from the Greek word for dance and describes the uncontrollable dance-like movements seen in people with HD. The hereditary nature of HD helps distinguish it from other types of chorea with infectious, metabolic, or hormonal causes. Understanding the hereditary nature of HD eventually enabled modern researchers to pinpoint the cause of the disease-a mutation or misspelling in a single gene.

More than 30,000 Americans have HD. Although the mutation is present from birth, symptoms of HD typically appear in middle age (adult HD), and in rare cases they appear in children (juvenile HD). The disease, which gets progressively worse, attacks motor control regions of the brain, as well as other areas. Chorea, abnormal body postures, and impaired coordination are among the most visible symptoms. But HD also causes changes in emotion and cognition (thinking) that can be devastating for people with the disorder and for their families.

Although there is no cure for HD, treatments are available to help manage its symptoms and other potential treatments are under investigation to slow or stop its course. And there are now genetic tests available for HD, which gives people at risk for the disease the option to plan for their health and the health of future generations.

How does HD affect the brain?

The most severe loss of nerve cells (also called neurons) occurs in deep brain structures called the basal ganglia, especially in a part of the basal ganglia called the striatum. The basal ganglia have a variety of functions, including helping to control voluntary (intentional) movement. Subsections of the basal ganglia, called the caudate nuclei and putamen, are most severely affected. Another strongly affected area is the brain's outer surface, or cerebral cortex, which has important roles in movement, as well as thought, perception, memory, and emotion. As HD progresses over time, neuronal degeneration becomes more widespread throughout the brain. In addition to metabolic changes, there is degeneration in areas of the brain that control hormones.

How is HD inherited?

HD is passed from parent to child through a mutation in a gene. Genes contain the blueprint for who we are, from our outer appearance to the composition and workings of our internal organs, including the brain. The gene responsible for HD lies on chromosome 4.

When a parent has HD, each child has a 50 percent chance of inheriting the copy of chromosome 4 that carries the HD mutation. If a child does not inherit the HD mutation, he or she will not develop the disease and cannot pass it to subsequent generations. In some families, all the children may inherit the HD gene; in others, none do. Whether one child inherits the gene has no bearing on whether others will or will not share the same fate. A person who inherits the HD mutation and survives long enough will develop the disease.

To understand the HD gene mutation, it helps to know a little more about what genes are and what they do. Genes contain the instructions for making the approximately one million proteins that run everything in our bodies. The HD gene makes an essential protein called huntingtin, whose function is largely unknown but may be necessary for early nerve cell development. Huntingtin is most active in the brain. Genes are composed of deoxyribonucleic acid (DNA), a long chain-like molecule. The links in a DNA chain are called bases, or nucleotides, and there are four varieties-adenine, thymine, cytosine, and guanine-typically abbreviated as A, T, C, and G. Within each gene, a unique combination of these nucleotides serves as a code that determines the gene's function; changes in the code-such as through a mutation-can change a gene's function.

The disease-causing mutation inside the HD gene consists of a three-base sequence repeated many times. This type of mutation, called a triplet (or trinucleotide) repeat expansion, is responsible for dozens of other neurological diseases, but in each case the three-base sequence, or triplet, resides within a different gene. The triplet sequences also vary; in HD, the triplet consists of the bases C-A-G. Most people have fewer than 27 CAG repeats in the HD gene and are not at risk for the disease. Individuals with the disease may have 36 or more repeats. People who have repeats in the intermediate range (27-35) are unlikely to develop the disease, but they could pass it on to future generations.

When HD occurs without a family history, it is called sporadic HD. These cases can occur when one parent has an intermediate range of CAG repeats, sometimes called a premutation. Prior to conception of a child, the number of repeats may expand into the disease-causing range. Most often, these expansions occur in the father's sperm cells, rather than in the mother's egg cells. Each time the father's DNA is copied to make new sperm, there is a possibility for the number of CAG repeats to expand. This increase in disease severity from one generation to the next-with a younger onset and faster progression-is called anticipation.

What are the major effects of the disease?

Early signs of the disease vary greatly from person to person, but typically include cognitive or psychiatric symptoms, difficulties with movement, and behavioral changes. Symptoms of Huntington's disease include:

Behavioral changes. The individual experiences mood swings or becomes uncharacteristically irritable, apathetic, passive, depressed, or angry. These symptoms may lessen as the disease progresses or, in some individuals, may continue and include hostile outbursts, thoughts of suicide, deep bouts of depression, and, rarely, psychosis. Social withdrawal is common.

Cognitive/judgment changes. HD may affect a person's judgment, attention, and other cognitive functions. Early signs might include having trouble with driving, problem-solving or decision making, prioritizing tasks, and difficulty organizing, learning new things, remembering a fact, putting thoughts into words, or answering a question. Familiar tasks that were simple to complete when healthy now take longer or cannot be done at all. As the disease progresses, these cognitive problems worsen and affected individuals are no longer able to work, drive, or care for themselves. When the level of cognitive impairment is significant enough to impair daily functioning, it is described as dementia. Many people, however, remain aware of their environment and are able to express emotions. Some individuals cannot recognize other family members.

Uncontrolled and difficult movement. Movement problems may begin with uncontrolled movement in the fingers, feet, face, or trunk. These movements, which are signs of chorea, often intensify when the person is anxious or distracted and become larger and more apparent over time. HD can also begin with mild clumsiness or problems with balance. Some people develop chorea-related movements. Chorea often creates serious problems with walking, increasing the likelihood of falls. Some individuals with HD do not develop chorea; instead, they may become rigid and move very little, or not at all, a condition called akinesia. Others may start out with chorea but become rigid as the disease progresses. In addition to chorea, some individuals have unusual fixed postures, called dystonia. The two movement disorders can blend or alternate. Other symptoms may include tremor (unintentional rhythmic muscle movement in a back-and-forth manner) and abnormal eye movements that often occur early.

Physical changes. Speech becomes slurred and vital functions, such as swallowing, eating, speaking, and especially walking, continue to decline. Many people with HD lose weight as they encounter problems with feeding, swallowing, choking, and chest infections. Other symptoms may include insomnia, loss of energy, and fatigue. Some individuals with HD develop seizures. Eventually the person will be confined to a bed or wheelchair.

In general, the duration of the illness ranges from 10 to 30 years. The most common causes of death are infection (most often pneumonia) and injuries related to falls.

At what age does HD appear?

The rate of disease progression and the age at onset vary from person to person. As a general rule, having a higher number of CAG repeats is associated with an earlier onset and faster course of the disease. A common observation is that the earlier the symptoms appear, the faster the disease progresses.
A person can have early signs of HD and still have normal findings on a CT or MRI scan.
Adult HD

Adult-onset HD most often begins between ages 30-50. A few individuals develop HD after age 55. Diagnosis in these people can be very difficult. The symptoms of HD may be masked by or confused with other health problems, or the person may not display the severity of symptoms seen in individuals with HD of earlier onset. These individuals may also show symptoms of depression rather than anger or irritability, or they may retain sharp control over their intellectual functions, such as memory, reasoning, and problem-solving.

There is also a related disorder called senile chorea. Some elderly individuals develop choreic movements, but do not become demented, have a normal HD gene, and lack a family history of the disorder. Some scientists believe that a different gene mutation may account for this small number of cases, but this has not been proven.

Juvenile HD

Some individuals develop symptoms of HD before age 20. This is called early-onset or juvenile HD. A common early sign of juvenile HD is a rapid decline in school performance. Movement problems soon become apparent, but they differ from the chorea typically seen in adult-onset HD. One common motor symptom in juvenile HD is myoclonus, which involves rapid involuntary muscle twitches or jerks. Other motor symptoms typical in juvenile HD include slowness, rigidity (in which the muscles remain constantly tense), and tremor. This constellation of symptoms can resemble Parkinson's disease, and is sometimes called "akinetic-rigid" HD or the Westphal variant of HD. People with juvenile HD may also have seizures and mental disabilities. The earlier the onset, the faster the disease seems to progress. The disease progresses most rapidly in individuals with juvenile or early-onset HD, and death often follows within 10 years.

Individuals with juvenile HD usually inherit the disease from their fathers, who typically have a later onset form of HD themselves. To verify the link between the number of CAG repeats in the HD gene and the age at onset of symptoms, scientists studied a boy who developed HD symptoms at the age of two, one of the youngest and most severe cases ever recorded. They found that he had nearly 100 repeats. The boy's case was central to the identification of the HD gene and at the same time helped confirm that juveniles with HD have the longest segments of CAG repeats. This correlation has been confirmed in other studies.

How is HD diagnosed?

A diagnosis of Huntington's disease is generally based on findings from neurological, psychological, and genetic testing.

Neurological tests. A neurologist will interview the individual intensively to obtain the medical history and rule out other conditions. Tests of neurological and physical functions may review reflexes, balance, movement, muscle tone, hearing, walking, and mental status. A number of laboratory tests may be ordered as well, and individuals with HD may be referred to other health care professionals such as psychiatrists, genetic counselors, clinical neuropsychologists, or speech pathologists for specialized management and/or diagnostic clarification.

A tool used by physicians to diagnose HD is to take the family history, sometimes called a pedigree or genealogy. It is extremely important for family members to be candid and truthful with a professional who is taking a family history since another family member(s) may not have been accurately diagnosed with the disease but thought to have other issues.

Genetic tests. The most effective and accurate method of testing for HD-called the direct genetic test-counts the number of CAG repeats in the HD gene, using DNA taken from a blood sample. The presence of 36 or more repeats supports a diagnosis of HD. A test result of 26 or fewer repeats rules out HD. A small percentage of individuals will have repeats in a borderline range. For such individuals, doctors may try to get a clearer picture of disease risk by asking other family members to come in for examination and genetic testing.

Prior to the availability of the direct genetic test, clinics used a method called linkage testing. This older method requires a sample of DNA from a closely related affected relative, preferably a parent, for the purpose of identifying markers close to the HD gene. A version of the linkage method is sometimes still used for prenatal testing.

Diagnostic imaging. In some cases, especially if a person's family history and genetic testing are inconclusive, the physician may recommend brain imaging, such as computed tomography (CT) or, more likely, magnetic resonance imaging (MRI). As the disease progresses, these scans typically reveal shrinkage of the striatum and parts of the cortex, and enlargement of fluid-filled cavities within the brain called ventricles. These changes do not necessarily indicate HD, however, because they can occur in other disorders. Conversely, a person can have early symptoms of HD and still have normal findings on a structural CT or MRI scan.

What is predictive testing and how is it done?

A predictive or presymptomatic genetic test is an option for someone who has a family history of HD but shows no symptoms. Genetic testing makes it possible to predict with a higher degree of certainty whether or not the person will develop HD.

The decision to undergo presymptomatic testing is a highly personal and often difficult one to make. Common reasons that people choose to take the test include planning for marriage, children, education and career decisions, finances, stress, or simply to relieve uncertainty.

Centers across the U.S. offer genetic testing for HD, as well as pre- and post-test counseling. A list of such centers is available from the Huntington's Disease Society of America at 1-800-345- HDSA ( http://hdsa.org/abouthdsa/ locate-resources/?i=genetictesting). With the participation of families with HD, researchers and health professionals have developed guidelines for HD genetic testing. A team of specialists will help the at-risk person decide if testing is the right choice, and will carefully prepare the person for a negative, positive, or inconclusive test result. Whatever the results of genetic testing, the at-risk individual and family members can expect powerful and complex emotional responses. Because receiving test results may prove to be devastating, testing guidelines call for continued counseling even after the test is complete and the results are known.

Centers across the U.S. offer genetic testing for HD, as well as pre- and post-test counseling. A list of such centers is available from the Huntington's Disease Society of America at 1-800-345- HDSA ( http://hdsa.org/abouthdsa/ locate-resources/?i=genetictesting). With the participation of families with HD, researchers and health professionals have developed guidelines for HD genetic testing. A team of specialists will help the at-risk person decide if testing is the right choice, and will carefully prepare the person for a negative, positive, or inconclusive test result. Whatever the results of genetic testing, the at-risk individual and family members can expect powerful and complex emotional responses. Because receiving test results may prove to be devastating, testing guidelines call for continued counseling even after the test is complete and the results are known.

In order to protect the interests of minors, including confidentiality, testing is not recommended for those under the age of 18 unless there is a compelling medical reason (for example, the child is exhibiting symptoms).

Prenatal testing

Prenatal testing is an option for people who have a family history of HD and are concerned about passing the disease to a child. Before requesting a prenatal test, and even before pregnancy, it is a good idea to seek advice from a genetic counselor. Prenatal testing can be done using either the direct method or the linkage method. As with adult testing, the direct method provides higher certainty. However, in addition to revealing the HD gene status of the fetus, the direct method also reveals the status of the at-risk parent.

Hopeful parents who do want to know their own HD gene status may opt for the linkage method, which is also known as prenatal exclusion testing. This test does not look for the HD gene itself but instead indicates whether or not the fetus has inherited a chromosome 4 mutation from the affected grandparent. If the mutation is present, the parents then learn that the fetus's risk is the same as the at-risk parent (50 percent), but they learn nothing new about the parent's risk. If the test shows that the fetus has inherited a chromosome 4 mutation from the unaffected grandparent, then the fetus has not inherited HD.

Another option for parents is in vitro fertilization (IVF) and preimplantation genetic diagnosis (PGD). Briefly, a woman is given fertility drugs so that she produces many eggs at once, the eggs are fertilized by the man's sperm in vitro (literally, "in glass"), and embryos are screened at a very early stage to determine if they carry the HD mutation. Embryos free of the mutation are then implanted in the woman's uterus. Parents can choose not to know the exact results of genetic testing and thus are not forced to confront their own HD gene status. These procedures are available only at some specialized IVF clinics and require extensive counseling, preparation, and expense.

What treatments are available for HD?

A number of medications may be prescribed to help control emotional and movement problems associated with HD. It is important to remember however, that while medicines may help keep these clinical symptoms under control, there is no treatment to stop or reverse the course of the disease.

Most of the medications available for HD symptoms work by modulating neurotransmitters-the chemical messages that shuttle between neurons. For many of these drugs, their mechanisms of action against HD are not fully understood.

Tetrabenazine, which causes depletion of the neurotransmitter dopamine, is prescribed for treating Huntington's-associated involuntary movements, as is deutetrabenazine.

Antipsychotic drugs, such as risperidone, olanzapine, or haloperidol, or other drugs such as clonazepam, may help to alleviate choreic movements and may also be used to help control hallucinations, delusions, and violent outbursts. Antipsychotic drugs, however, typically do not help with the muscle contractions associated with dystonia (involuntary muscle contractions that can cause slow, repetitive movement or abnormal postures), and may in fact worsen the condition, causing stiffness and rigidity.

For depression, physicians may prescribe citalopram, fluoxetine, sertraline, nortriptyline, or other compounds. Tranquilizers can help control anxiety and lithium may be prescribed to combat pathological excitement and severe mood swings.

Drugs used to treat the symptoms of HD may have side effects such as fatigue, sedation, decreased concentration, restlessness, or hyperexcitability, and should be only used when symptoms create problems for the individual. For those on medication, it may be difficult to tell if a particular symptom, such as apathy or memory loss, is a sign of the disease or a drug reaction.

What kind of care do individuals with HD need?

Cognitive problems are often the first changes that are noticed in HD. Evaluations conducted by clinical neuropsychologists, who specialize in cognitive assessment, can be helpful in clarifying an individual's cognitive strengths and weaknesses, making safety recommendations and monitoring cognitive changes over time. Education about cognitive symptoms is also helpful for individuals and families. As the disease progresses, it is important to maintain regular daily routines for the person and to provide an environment with minimal distractions. Care should be taken not to isolate individuals who have become slow to engage in conversation or respond to questions. Speech therapy and other communication techniques may improve an individual's ability to communicate and remain active in family and community life.

It is extremely important for a person with HD to maintain physical fitness as much as the course of the disease allows. Individuals who exercise and keep active tend to do better than those who do not. A daily regimen of exercise can help the person feel better physically and mentally. Although their coordination may be poor, individuals should continue walking, with assistance if necessary. Wearing special padding may also help reduce injuries in the event of a fall. Wearing sturdy shoes that fit well can help too, especially shoes without laces that can be slipped on or off easily.

Impaired coordination may make it difficult for people with HD to feed themselves and to swallow. As the disease progresses, people with HD may even choke. In helping individuals to eat, caregivers should allow plenty of time for meals. While some foods may require the addition of thickeners, other foods may need to be thinned. Some individuals may benefit from swallowing therapy, which is especially helpful if started before serious problems arise. Suction cups for plates, special tableware designed for people with disabilities, and plastic cups with tops can help prevent spilling. The individual's physician can offer additional advice about diet and about how to handle swallowing difficulties or gastrointestinal problems that might arise, such as incontinence or constipation.

Proper nutrition is needed to ensure the individual with HD takes in enough calories to maintain body weight. Sometimes people with HD, who may burn as many as 5,000 calories a day through involuntary movements, require five meals a day to take in the necessary number of calories. Physicians may recommend vitamins or other nutritional supplements. When swallowing and nutritional problems become severe, some individuals and their families choose to use a feeding tube.

Individuals with HD are at special risk for dehydration and therefore require large quantities of fluids, especially during hot weather. Bendable straws can make drinking easier for the person. In some cases, water may have to be thickened with commercial additives to give it the consistency of syrup or honey.

What community resources are available?

Individuals and families affected by HD can take steps to ensure that they receive the best advice and care possible. Advocacy organizations including the Huntington's Disease Society of America (HDSA) and the Hereditary Disease Foundation are excellent resources with information specific to HD. Some organizations support scientific workshops and research and provide information that enables families, health professionals and investigators to exchange information, learn of available services and benefits, and work toward common goals. HD support groups exist in many states across the country. State and local health service agencies can provide information on community resources and family support groups that may exist. Possible types of help include:

Legal and social aid. Since HD affects a person's capacity to reason, make judgments, and handle responsibilities, individuals may need help with legal affairs. Wills and other important documents should be drawn up early to avoid legal problems when the person with HD may no longer be able to represent his or her own interests. Family members should also seek out assistance if they face discrimination regarding insurance, employment, or other matters.

Home care services. Caring for a person with HD at home can be exhausting, but part-time assistance with household chores or physical care of the individual can ease this burden. Domestic help, meal programs, transportation programs, nursing assistance, occupational therapy, or other home services may be available from federal, state, or local health service agencies.

Recreation and work centers. Many people with HD are eager and able to participate in activities outside the home. Therapeutic work and recreation centers give individuals an opportunity to pursue hobbies and interests and to meet new people. Participation in these programs, including occupational, music, and recreational therapy, can reduce the person's dependence on family members and provides home caregivers with a temporary, much needed break.

Group housing. A few communities have group housing facilities that are supervised by a resident attendant and that provide meals, housekeeping services, social activities, and local transportation services for residents. These living arrangements are particularly suited to the needs of individuals who are alone and who, although still independent and capable, risk injury when they undertake routine chores like cooking and cleaning.

Institutional care. The individual's physical and emotional demands on the family may eventually become overwhelming. While many families may prefer to keep relatives with HD at home whenever possible, a long-term care facility may prove to be best. To hospitalize or place a family member in a care facility is a difficult decision that may require professional counseling.

Finding the proper facility can itself prove difficult. Organizations such as the HDSA may have referrals to facilities that have had experience in the care of individuals with HD. Very few of these exist however, and even fewer have experience with individuals with juvenile or early-onset HD who require special care because of their age and symptoms.

What research is being done?

The mission of the National Institute of Neurological Disorders and Stroke (NINDS) is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease. The NINDS is a component of the National Institutes of Health (NIH), the

leading supporter of biomedical research in the world. The NINDS conducts and supports research to better understand and diagnose Huntington's disease (HD), develop new treatments, and ultimately, prevent HD. The NINDS also supports training for the next generation of HD researchers and clinicians, and serves as an important source of information for people with HD and their families.

NINDS-funded research has played a key role in our understanding of HD-helping to localize the HD-causing gene to chromosome 4 and identifying the mutation that causes HD. These findings have proven invaluable for diagnosis and research, and have enabled neuroscientists to create animal models of the disorder. Signs of HD have been reproduced in fruit flies, mice, and non-human primates by giving the animals one or more copies of the HD mutations found in people. These models are used to study mechanisms of the disease, to identify potential therapeutic strategies, and to move forward with those strategies most likely to work and least likely to cause harm for individuals. Just as important, the gene discovery enables neurologists to recruit individuals who carry the HD gene into clinical studies early-before they become ill.

The HD Gene

How do mutations in the HD gene lead to neuronal degeneration? The normal functions of the huntingtin (Htt) protein-the product of the HD gene-have yet to be fully defined, but may include regulating the development of the embryo, transport of molecules and organelles inside nerve cells, and controlling factors that support neuronal health. However, there is very strong evidence that the mutant Htt protein gains one or more new and harmful functions. A major focus of research on HD is to understand the toxicity of mutant huntingtin protein and to develop potential drugs for counteracting it.

People with HD have an abnormal, repetitive, greatly expanded three-letter code, called a CAG repeat, in their DNA sequence. DNA uses a threeletter code (or triplet) to prescribe the order and identity of amino acids-a protein's building blocks. The triplet "CAG" designates the amino acid glutamine. The repeated CAGs in the normal HD gene are translated into a string of glutamines, called polyglutamine. The mutant HD gene codes for an abnormal form of the Htt protein with much longer polyglutamine repeats that are toxic to neurons. Also, the abnormal polyglutamine sequence affects how the huntingtin protein interacts with other proteins. At least eight other inherited neurological disorders are caused by polyglutamine expansions, each in a different gene.

RNA serves as an intermediate between DNA molecules and proteins; the genetic code within DNA is copied into RNA, which is then used as a template for making proteins. The mutant huntingtin protein RNA may itself be toxic to cells; its numerous repeats can attract and bind essential cellular proteins which thus become unavailable to perform their critical function in processing other RNA molecules from other genes.

NINDS is funding cutting-edge research that aims to eliminate or reduce the production of toxic HD-RNA and huntingtin protein. One potential therapy, called RNA interference, involves designing small bits of synthetic RNA to match, target, and destroy specific RNA molecules inside cells. Researchers have designed interfering RNAs that target HD-RNA and block the production of mutant huntingtin protein, and they have found this approach to be beneficial in mouse models of HD. Such synthetic RNA molecules called antisense oligonucleotides are being developed to be delivered into the cerebrospinal fluid. Others are packaging the RNA into viruses to deliver into the brain. Pharmaceutical companies are now initiating ambitious trials to test whether this approach may help people with HD.

Mutant Huntingtin Protein

Aberrant regulation of genes in HD. The abnormal interactions between mutant huntingtin protein and other proteins can have many adverse consequences, including altered gene regulation. Humans have approximately 20,000 genes, about one-third of which are active (or expressed) in the brain at some point in life. Precisely when and where these genes are expressed is controlled by a complex machinery within cells-and mutant Htt can upset this system. For instance, DNA in the cells of higher organisms is packed into chromatin-tight coils of DNA and small proteins called histones. Compounds that block gene expression and coiltightening activity of certain histones have been shown to counteract HD in animal models, and are attractive candidates for drug development. Other alterations in chromatin not only keep some necessary genes shut off, but mutant Htt can also inappropriately turn on other genes, such as those driving excessive inflammation, which damages and kills nerve cells in the brain.

Mutant Htt aggregation. Besides sticking to other proteins, mutant Htt has a tendency to stick to copies of itself and accumulate in clumps known as aggregates. These aggregates can pull in and block the activity of other proteins, and grow to form inclusion bodies-protein deposits inside cells that may overburden the cell's ability to handle and dispose of old or damaged proteins. Neurons from different brain regions may differ in their efficiency of waste disposal. Neurons in the striatum, the brain region most affected in HD, show the slowest mutant huntingtin clearance rates, perhaps explaining their heightened susceptibility to the disease. Compounds that activate cellular waste handling systems have been shown to reduce the toxicity of mutant Htt in animal models. Recent evidence suggests that mutant huntingtin may also move from cell to cell in a person's brain and induce aggregates and inclusions in neighboring cells, similar to what is seen in Alzheimer's and Parkinson's diseases.

Metabolism and mitochondria. Some studies suggest that mutant Htt interferes with the function of the tiny energy factories inside cells known as mitochondria. Others point to reduced efficiency of antioxidant pathways-protective pathways that scavenge harmful byproducts of brain activity that in normal conditions remain at innocuous levels. In HD some of these pathways are disrupted and the toxic byproducts accumulate to damaging levels. Drugs that inhibit the production of these harmful byproducts or accelerate their clearance have been designed and successfully tested in animal models. However, two NINDS-funded trials investigating any benefit of the metabolic supplements creatine and coenzyme Q10 in people with HD found no improvements in clinical symptoms at the doses tested.

Excitotoxicity, neural circuits, and survival factors. Researchers have yet to determine why Huntington's disease has its most severe effects on neurons in the striatum, specifically on a cell type called mediumsized spiny neurons. One culprit may be the brain chemical glutamate, which is produced by neurons in the cerebral cortex and transmits information by exciting (signaling them to turn on) medium spiny neurons in the striatum. Excessive glutamate signaling between these cells may lead to overexcitation of medium spiny neurons in HD. Chronic over-excitation is toxic to neurons (called excitotoxity). Several labs are investigating whether drugs that counteract excitotoxicity might help against HD.

Some of the clinical symptoms in neurodegenerative diseases may be caused by the ultimate malfunctioning of neuronal circuits rather than by the loss of individual cells. Cutting-edge methods such as optogenetics (where neurons are activated or silenced in the brains of living animals using light beams) are being used to probe the cause and progression of such circuit defects in HD.

In addition to communications exchange, neurons may also provide each other with chemical signals (called trophic factors) that support the health and stability of neural circuits. Cortical neurons provide trophic support by releasing Brain Derived Neurotrophic Factor (BDNF), which supports the survival of medium spiny neurons in the striatum. Evidence suggests that mutant Htt suppresses the production of BDNF. Using animal models, researchers hope to restore BNDF-based trophic support to striatal cells and possibly prevent medium spiny neurons from dying.

Stem Cells

Stem cells are now a useful tool that helps us understand underlying molecular disease mechanisms.

Pluripotency-the ability of embryonic stem cells to become nerve, muscle, bone, and other cell types-depends on a unique genetic program that is typically shut off in adult cells. Scientists have discovered that it is possible to take adult blood or skin cells and, by activating this genetic program, return the cells to a pluripotent state (called induced pluripotent, or iPS, cells). Through an NINDS-funded consortium, individuals with HD have donated skin and blood samples for research, allowing the creation of iPS cell lines and iPSderived neurons for studying HD. Researchers are using cultures of these cell lines to understand why neurons malfunction and die in HD, and to rapidly test potential new drugs. Their aim is increase the efficiency of turning a person's iPS cells into medium spiny neurons that reflect the human disease, and then to learn from these disease cells how the CAG-repeat expansion damages their function and viability.

Investigators are studying the effects of transplanting nerve cells derived from embryonic or adult stem cells (immature cells that eventually give rise to all of the body's cell types) or fetal tissue. A number of small studies found no sustained improvement in transplanting fetus-derived cells into the striatum in people with HD.

In theory, induced pluripotent stem cells could be derived from a person with Huntington's disease and then implanted into the person's brain after correcting the HD mutation. However, brain function is dependent upon the correct connections between neurons and currently it is not known how to generate cells to form connections appropriately in a disease such as HD.

An alternative to transplanting stem cells into the brain may be to mobilize stem cells that are already there and shown to move into damaged tissue. Research on rodent models of HD suggests it might be possible to reawaken these cells by delivering specific growth factors to the brain. It is not yet clear whether this strategy will work in humans, as those with HD seem to have significantly fewer and less potent brain stem cells than healthy people.
NIH Publication No. 17-NS-19
Biomarkers
See a list of all NINDS Disorders Publicaciones en Español Enfermedad de Huntington
The NINDS-funded PREDICT-HD study, as well as several international studies (such as REGISTRY, BIOHD, and Enroll-HD), seek to identify biomarkers for HD. Biomarkers are biological changes that can be used to predict, diagnose, or monitor a disease; for example, a sustained rise in blood sugar is a biomarker for diabetes. One goal of PREDICT-HD is to determine if the progression of the disease correlates with changes in brain scan images, or with chemical changes in blood, urine, or cerebrospinal fluid. Another goal is to find biomarkers characteristic of prediagnostic HD; measurable changes in personality, mood, and cognition that typically precede the appearance motor symptoms of HD.

A large and related NINDS-supported study aims to identify additional genetic factors in people that influence the course of the disease. Individuals with the same CAG expansions can differ widely in the age of disease onset and severity of symptoms. Researchers are trying to identify variations in the genomes of individuals with HD that account for those differences. Finding genetic variants that slow or accelerate the pace of disease progression promise to provide important new targets for disease intervention and therapy.

Clinical Studies

Studies of cognition, emotional functioning, and movement. Studies of motor problems (abnormal eye movements, chorea, and dystonia), psychiatric symptoms (apathy, psychosis, depression, and irritability), and tests of cognitive skills (learning and memory, attention, concentration, and executive functioning such as multitasking, problem-solving, and planning) may serve to identify when the symptoms of HD appear, and help characterize their range and severity as the disease progresses over time.

Clinical trials of drugs. Testing investigational drugs may lead to new treatments and at the same time improve our understanding of the disease process in HD. Classes of drugs being tested include those that control symptoms, slow the rate of progression of HD, block the effects of excitotoxins, provide support factors that improve neuronal health, or suppress metabolic defects that contribute to the development and progression of HD.

Imaging. Various imaging technologies allow investigators to view changes in the volume and structures of the brain, and to pinpoint when these changes occur in HD. Positron emission tomography (PET, which visualizes metabolic or chemical abnormalities in the brain) allows scientists to learn how HD affects the chemical systems of the brain. Investigators hope to learn if PET scans can reveal abnormalities that signal HD, as well as to characterize neurons that have died and chemicals that are depleted in parts of the brain of people with HD. Investigators are using functional MRI (fMRI), a form of magnetic resonance imaging that measures changes in the flow of blood-born chemicals known to correlate with brain activity, to understand how HD affects the functioning of different regions of the brain.

Brain structure. Altered brain development may play an important role in HD. Huntingtin is expressed during embryonic development and throughout life. Studies in animals have shown that the normal HD gene is vital for brain development. Adults who carry the mutant HD gene but have not yet displayed symptoms of the disease show measurable changes in the structure of their brain, even up to 20 years before onset of clinical diagnosis. It is not known when in life these changes become evident. One possibility is that the HD gene causes changes in early brain development that remain throughout life, and initially cause only subtle functional abnormalities.

In an effort to better understand how HD affects brain development, an NINDS-funded study is evaluating brain structure and function in children, adolescents, and young adults (ages 6-18) who are at risk for developing the disease because they have a parent or grandparent with HD. Participants who carry the expanded gene will be compared to individuals who carry the gene but have CAG repeats of 39 or less, as well as to individuals who do not have a history of HD in their family. Changes in brain structure and/or function in the gene-expanded group may point to a developmental component in HD.

Where can I get more information?

For more information on neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute's Brain Resources and Information Network (BRAIN) at:

BRAIN
P.O. Box 5801
Bethesda, MD 20824
800-352-9424
http://www.ninds.nih.gov

Additional information on Huntington's disease is available by contacting:

Hereditary Disease Foundation
3960 Broadway
6th Floor
New York, NY 10032
cures@hdfoundation.org
http://www.hdfoundation.org
Tel: 212-928-2121
Fax: 212-928-2172

Huntington's Disease Society of America
505 Eighth Avenue
Suite 902
New York, NY 10018
hdsainfo@hdsa.org
http://hdsa.org
Tel: 212-242-1968; 800-345-HDSA (4372)
Fax: 212-239-3430

National Library of Medicine
Genetics Home Reference
National Institutes of Health
8600 Rockville Pike
Bethesda, MD 20894
www.nlm.nih.gov
301-594-5983
888-346-3656

-decreased body movements.

at-risk -a description of a person whose mother or father has HD or has inherited the HD gene and who therefore has a 50-50 chance of inheriting the disorder.

autosomal dominant disorder -a non-sex-linked disorder that can be inherited even if only one parent passes on the defective gene.

basal ganglia -a region located at the base of the brain composed of four clusters of neurons, or nerve cells. This area is responsible for body movement and coordination. The neuron groups most prominently and consistently affected by HD-the pallidum and striatum-are located here. See neuron, pallidum, striatum.

caudate nuclei -part of the striatum in the basal ganglia. See basal ganglia, striatum.

chorea -uncontrolled body movements. Chorea is derived from the Greek word for dance.

chromosomes -the structures in cells that contain genes. They are composed of deoxyribonucleic acid (DNA) and proteins and, under a microscope, appear as rod-like structures. See deoxyribonucleic acid (DNA), gene.

computed tomography (CT)- a technique used for diagnosing brain disorders. CT uses a computer to produce a high-quality image of brain structures. These images are called CT scans.

cortex -part of the brain responsible for thought, perception, and memory. HD affects the basal ganglia and cortex. See basal ganglia.

deoxyribonucleic acid (DNA)- the substance of heredity containing the genetic information necessary for cells to divide and produce proteins. DNA carries the code for every inherited characteristic of an organism. See gene.

dominant -a trait that is apparent even when the gene for that disorder is inherited from only one parent. See autosomal dominant disorder, recessive, gene.

gene -the basic unit of heredity, composed of a segment of DNA containing the code for a specific trait. See deoxyribonucleic acid (DNA).

huntingtin -the protein encoded by the gene that carries the HD defect. The repeated CAG sequence in the gene causes an abnormal form of huntingtin to be formed. The function of the normal form of huntingtin is not yet known.

kindred -a group of related persons, such as a family or clan.

magnetic resonance imaging (MRI) -an imaging technique that uses radiowaves, magnetic fields, and computer analysis to create a picture of body tissues and structures.

marker -a piece of DNA that lies on the chromosome so close to a gene that the two are inherited together. Like a signpost, markers are used during genetic testing and research to locate the nearby presence of a gene. See chromosome, deoxyribonucleic acid (DNA).

mitochondria -microscopic, energy-producing bodies within cells that are the cells' "power plants."

mutation -in genetics, any defect in a gene. See gene.

myoclonus -a condition in which muscles or portions of muscles contract involuntarily in a jerky fashion.

neuron -Greek word for a nerve cell, the basic impulse-conducting unit of the nervous system. Nerve cells communicate with other cells through an electrochemical process called neurotransmission.

neurotransmitters -special chemicals that transmit nerve impulses from one cell to another.

pallidum -part of the basal ganglia of the brain. The pallidum is composed of the globus pallidus and the ventral pallidum. See basal ganglia.

positron emission tomography (PET)- a tool used to diagnose brain functions and disorders. PET produces three-dimensional, colored images of chemicals or substances functioning within the body. These images are called PET scans. PET shows brain function, in contrast to CT or MRI, which show brain structure.

prevalence -the number of cases of a disease that are present in a particular population at a given time.

putamen -an area of the brain that decreases in size as a result of the damage produced by HD.

receptor -proteins that serve as recognition sites on cells and cause a response in the body when stimulated by chemicals called neurotransmitters. They act as on-and-off switches for the next nerve cell. See neuron, neurotransmitters.

recessive -a trait that is apparent only when the gene or genes for it are inherited from both parents. See dominant, gene.

senile chorea -a relatively mild and rare disorder found in elderly adults and characterized by choreic movements. It is believed by some scientists to be caused by a different gene mutation than that causing HD.

striatum -part of the basal ganglia of the brain. The striatum is composed of the caudate nucleus, putamen, and ventral striatum. See basal ganglia, caudate nuclei.

trait -any genetically determined characteristic. See dominant, gene, recessive.

transgenic mice-mice that receive injections of foreign genes during the embryonic stage of development. Their cells then follow the "instructions" of the foreign genes, resulting in the development of a certain trait or characteristic. Transgenic mice can serve as an animal model of a certain disease, telling researchers how genes work in specific cells.

ventricles -cavities within the brain that are filled with cerebrospinal fluid. In HD, tissue loss causes enlargement of the ventricles.

"Huntington's Disease: Hope Through Research", NINDS, Publication date December 2017

Back to Huntington's Disease Information Page

Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.

All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.

# data[].attributes.attachment_link.title
National Institute of Neurological Disorders and Stroke

# data[].attributes.attachment_link.description
What is Huntington's disease? How is HD diagnosed? Prenatal testing What treatments are available for HD? Where can I get more information? Glossary What kind of care do individuals with HD need? What community resources are available? What research is being done? What is predictive testing and how is it done?

# data[].attributes.body
Sections of the basal ganglia are the most severely affected. This part of the brain has many functions such as controlling voluntary movement.
The Cerebral Cortex is also affected, which supports movement, thought, perception and memories.