Overview
Huntington's disease (HD) is an inherited disease that affects movement, thinking, emotions, and behavior. The symptoms of HD usually start in a person's thirties or forties, but may begin at any age. HD is due to a gene, part of our DNA, with an abnormally long repeated section, called CAG repeats. Presence of CAG repeats causes brain cells to die. The symptoms of HD are due to the loss of brain cells. Because genes are passed from parent to child, HD can be inherited.

Symptoms
The symptoms of HD develop and become more severe over time. They include:

• Chorea: involuntary, jerky movements that may affect the arms, legs, trunk, or face. Difficulty swallowing and loss of the ability to move occur later in the disease.
• Dementia: loss of the ability to remember, plan, make appropriate decisions, or understand complex information or instructions.
• Personality changes: irritability, agitation, suspiciousness, impulsiveness, loss of pleasure, depression.

HD impairs the ability to work and participate in activities of daily living. As the disease progresses, the person with HD requires more constant care.

Diagnosis
If a person has symptoms of HD, the diagnostic process includes testing for the expanded CAG repeat in the gene that causes HD. This requires a blood sample, which is sent to a special laboratory for testing. A complete medical history is important and your doctor will ask many questions about previous illnesses. Because HD is inherited, the family history may also provide information that is helpful in making the diagnosis of HD. Other diagnostic procedures may include making an image of the brain to look for loss in the amount of brain tissue.

Before symptoms appear, a person who is at known risk for HD may obtain a test for the CAG repeat. As discussed below, this should only be done after genetic counseling.

Treatment
There is no treatment that slows or halts Huntington's disease. Tetrabenazine (not yet available in the US) reduces chorea. Certain antipsychotic agents, such as haloperidol (Haldol®) or benzodiazepines, such as clonazepam (Klonopin®), may partially suppress choreic movements and help to control psychiatric abnormalities, including severe agitation, hallucinations, or psychotic delusions. Other drugs may help improve the psychiatric symptoms, such as agitation and depression. Speech therapy may help the person with HD to communicate better despite loss of speech muscle control. An occupational therapist may suggest tools and techniques for carrying out daily activities despite the loss of muscle control in the arms and trunk. Physical therapy is useful for balance and walking. A feeding tube, which delivers food directly into the stomach, may be needed if the disease is advanced. Psychological counseling and/or psychiatric care is very important for both the patient and the family.

Genetic Counseling
Because HD is inherited, family members need to consider whether they wish to be tested for the presence of the gene that causes HD. This decision should only be made after consulting with a genetic counselor. A genetic counselor is trained to help family members think through the decision to test and discuss the pros and cons of knowing and not knowing. This helps family members to reach the best decision for themselves. The genetic counselor also meets with family members after testing to work through the results of the test and what it means for them. For those who do have the gene, post-test psychological counseling is important to cope with the prospect of later disease. Those who learn they are not at risk for disease may also need counseling as they begin to reshape their outlook on their future.

Outlook
The symptoms of HD get worse over time. The disease duration is usually 15 to 20 years when it begins in adulthood. Those with earlier disease onset usually have a more severe and rapidly progressing disease course.

Questions to Ask Your Doctor

• What additional resources are in my area for dealing with my disease? Support groups? Clinical teams that specialize in HD or other movement disorders?
• Are there any experimental clinical trials for HD available to me?
• What type of doctors or other support people need to be on my treatment team?
• How can I contribute to research studies on HD?

If you would like more detailed information on the symptoms, diagnosis, and treatment options or additional support (such as discussion forums and chat rooms), please visit www.wemove.org.