About huntington's disease
What is huntington's disease?
Huntington's disease (HD) is a complex disorder that affect's a person's ability to feel, think, and move. Symptoms tend to worsen over time and the disease often runs in families. In people with one parent with HD, the chances of them developing it are 50-50.
- Huntington's disease is caused by a genetic degeneration of nerve cells in certain areas of the brain.
- Symptoms of HD include mood swing, irritability, depression, and anger. The disease may affect a person's judgment, memory, and other cognitive functions. In some, there can be uncontrolled movements in the fingers, feet, face, or trunk, or problems with coordination or balance.
- Adult-onset HD, with its disabling, uncontrolled movements, most often begins in middle age, however HD can begin at any age and the disease tends to progress more rapidly the earlier it begins.
- Huntington's disease is diagnosed by taking family history, CT scans, or MRIs.
- Presymptomatic genetic testing may be done on people who do not show symptoms but have a parent with the disease.
- There is no treatment to stop or reverse Huntington's disease, however there are some medications that can help keep symptoms under control. Treatment for HD includes the drug tetrabenazine, antipsychotic drugs, antidepressants, and tranquilizers.
- Patients who exercise tend to do better than those who do not.
- A person with HD may need assistance such as home care, or occupational therapy. Contact the Huntington's Disease Society of America for more information.
Introduction to Huntington's disease
In 1872, the American physician George Huntington wrote about an illness that he called "an heirloom from generations away back in the dim past." He was not the first to describe the disorder, which has been traced back to the Middle Ages at least. One of its earliest names was chorea,* which, as in "choreography," is the Greek word for dance. The term chorea describes how people affected with the disorder writhe, twist, and turn in a constant, uncontrollable dance-like motion. Later, other descriptive names evolved. "Hereditary chorea" emphasizes how the disease is passed from parent to child. "Chronic progressive chorea" stresses how symptoms of the disease worsen over time. Today, physicians commonly use the simple term Huntington's disease (HD) to describe this highly complex disorder that causes untold suffering for thousands of families.
More than 15,000 Americans have HD. At least 150,000 others have a 50 percent risk of developing the disease and thousands more of their relatives live with the possibility that they, too, might develop HD.
Until recently, scientists understood very little about HD and could only watch as the disease continued to pass from generation to generation. Families saw the disease destroy their loved ones' ability to feel, think, and move. In the last several years, scientists working with support from the National Institute of Neurological Disorders and Stroke (NINDS) have made several breakthroughs in the area of HD research. With these advances, our understanding of the disease continues to improve.
This brochure presents information about HD, and about current research progress, to health professionals, scientists, caregivers, and, most important, to those already too familiar with the disorder: the many families who are affected by HD.
What are the symptoms for huntington's disease?
Huntington's disease usually causes movement, cognitive and psychiatric disorders with a wide spectrum of signs and symptoms. Which symptoms appear first varies greatly among affected people. During the course of the disease, some disorders appear to be more dominant or have a greater effect on functional ability.
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 abnormal eye movements
- Impaired gait, posture and balance
- Difficulty with the physical production of speech or swallowing
Impairments in voluntary movements — rather than the involuntary movements — may have a greater impact on a person's ability to work, perform daily activities, communicate and remain independent.
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
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
- 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 symptoms, 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 themselves early in the course of the disease include:
- Loss of previously learned academic or physical skills
- Rapid, significant drop in overall school performance
- Behavioral problems
- Contracted and rigid muscles that affect gait (especially in young children)
- Changes in fine motor skills that might be noticeable in skills such as handwriting
- Tremors or slight involuntary movements
When to see a doctor
See your doctor 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.
What are the causes for huntington's disease?
Huntington's disease is caused by an inherited defect in a single gene. Huntington's disease is an autosomal dominant disorder, which means that a person needs only one copy of the defective 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 defective gene could pass along the defective copy of the gene or the healthy copy. Each child in the family, therefore, has a 50 percent chance of inheriting the gene that causes the genetic disorder.
What are the treatments for huntington's disease?
No treatments can alter the course of Huntington's disease. But medications can lessen some symptoms of movement and psychiatric disorders. And multiple interventions can help a person adapt to changes in abilities for a certain amount of time.
A psychotherapist — a psychiatrist, psychologist or clinical social worker — can provide talk therapy to help with behavioral problems, develop coping strategies, manage expectations during progression of the disease and help family members communicate with each other.
Huntington's disease can significantly impair control of muscles of the mouth and throat that are essential for speech, eating and swallowing. A speech therapist can help improve your ability to speak clearly or teach you to use communication devices — such as a board covered with pictures of everyday items and activities. Speech therapists can also address difficulties with muscles used in eating and swallowing.
A physical therapist can teach you appropriate and safe exercises that enhance strength, flexibility, balance and coordination. These exercises can help maintain mobility as long as possible and may reduce the risk of falls.
Instruction on appropriate posture and the use of supports to improve posture may help lessen the severity of some movement problems.
When the use of a walker or wheelchair is required, the physical therapist can provide instruction on appropriate use of the device and posture. Also, exercise regimens can be adapted to suit the new level of mobility.
An occupational therapist can assist the person with Huntington's disease, family members and caregivers on the use of assistive devices that improve functional abilities. These strategies may include:
- Handrails at home
- Assistive devices for activities such as bathing and dressing
- Eating and drinking utensils adapted for people with limited fine motor skills
What are the risk factors for huntington's disease?
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.
Is there a cure/medications for huntington's disease?
Medications will likely evolve over the course of the disease, depending on overall treatment goals. Also, drugs that treat some symptoms may result in side effects that worsen other symptoms. Treatment goals will be regularly reviewed and updated.
Medications for movement disorders
Drugs to treat movement disorders include the following:
- Drugs to control movement include tetrabenazine (Xenazine) and deutetrabenazine (Austedo), which have been specifically approved by the Food and Drug Administration to suppress the involuntary jerking and writhing movements (chorea) associated with Huntington's disease. These drugs don't have any effect on the progression of the disease, however. Possible side effects include drowsiness, restlessness, and the risk of worsening or triggering depression or other psychiatric conditions.
Antipsychotic drugs, such as haloperidol and fluphenazine, have a side effect of suppressing movements. Therefore, they may be beneficial in treating chorea. However, these drugs may worsen involuntary contractions (dystonia), restlessness and drowsiness.
Other drugs, such as olanzapine (Zyprexa) and aripiprazole (Abilify), may have fewer side effects but still should be used with caution, as they may also worsen symptoms.
- Other medications that may help suppress chorea include amantadine (Gocovri, Osmolex ER), levetiracetam (Keppra, Elepsia XR, Spritam) and clonazepam (Klonopin). However, side effects may limit their use.
Medications for psychiatric disorders
Medications to treat psychiatric disorders will vary depending on the disorders and symptoms. Possible treatments include the following:
- Antidepressants include such drugs as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac) and sertraline (Zoloft). These drugs may also have some effect on treating obsessive-compulsive disorder. Side effects may include nausea, diarrhea, drowsiness and low blood pressure.
- Antipsychotic drugs such as quetiapine (Seroquel) and olanzapine (Zyprexa) may suppress violent outbursts, agitation, and other symptoms of mood disorders or psychosis. However, these drugs may cause different movement disorders themselves.
- Mood-stabilizing drugs that can help prevent the highs and lows associated with bipolar disorder include anticonvulsants, such as divalproex (Depakote), carbamazepine (Tegretol, Carbatrol, Epitol, others) and lamotrigine (Lamictal).