Huntington's disease (HD) is a genetic disease (inherited from a parent) that affects the brain and causes unsteady and uncontrollable movements in the hands, feet, and face. These abnormal movements eventually affect such activities as walking, talking, and swallowing. Psychiatric and behavioral problems are also very common and may often be harder to manage than the involuntary movements themselves.
A person is at risk for HD if he or she inherits the abnormal HD gene from a parent. A child whose parent has the HD mutation has a 50% chance of inheriting the gene; anyone who inherits the gene will eventually develop HD symptoms, although the exact age is variable. Often, the onset of HD may be earlier than it was in the prior generation.
HD can affect people at any age. The term "juvenile" HD refers to development of the disease in a child. People who get HD as a child tend to have a more progressive illness, seizures and more stiffness (less involuntary movements).
Huntington's disease is caused by the destruction of nerve cells (neurons) located in the basal ganglia (an area deep inside the brain that is responsible for controlling body movement). The cortex (surface of the brain) may also be affected; this underlies intellectual functions such as thinking, decision-making and memory.
Huntington's disease affects a person both physically and mentally. One of the first physical symptoms are unintended muscle movements, called “chorea,” that appear abrupt and random. Chorea is derived from the Greek word for dance and is best described as slow, dance-like movements that may affect the limbs, torso and face. The average age of onset is 40.
Physical problems may start out in small ways—for example, clumsiness, or losing balance—and then get worse over time. Chorea can make speaking, eating, and walking more difficult, and may also affect the person's ability to perform daily functions, such as driving. Patients with HD are also at risk for falls. HD patients may sometimes develop “bradykinesia” or “akinesia,” where their movements and speech are slower and less animated, typically later in the disease.
The early behavioral signs of HD include increased irritability, mood swings, obsessional thinking, depression, and/or anger. Over time, patients with HD may develop problems with memory, multi-tasking, and attention. Sometimes, these mental changes precede physical signs for years.
HD is a progressive disease; this means that it gets worse over time, and coordination of everyday activities become harder and harder. Depending on the person's age, he or she may suffer with HD for up to 30 years. HD is not fatal, but people who have it most commonly die from infection, injuries related to falls, or malnutrition.
Because HD is an inherited condition, the doctor will need to know if anyone else in the family has the disease. The doctor will perform a physical examination of the patient, paying close attention to abnormal movements such as chorea, as well as balance, reflexes and coordination.
In addition, the doctor may order brain imaging tests such as magnetic resonance imaging (MRI) or computed tomography (CT) scans, and blood tests, to see if there are any diseases that may produce changes similar to HD symptoms.
If the blood tests are negative and the doctor feels that the patient has examination findings consistent with HD (usually with a family history), the doctor may consider genetic testing for HD.
The HD genetic test should only be performed after the patient has received thorough counseling, allowing for reflection about the risks and benefits of testing. In the majority of instances, this counseling should be done by a genetic counselor who specializes in HD. In some instances, family members who are well (no obvious symptoms) may want to be tested to know if they carry the abnormal gene. They also should be referred for genetic counseling prior to testing. The genetic test is similar to a routine blood test, but the result may take several weeks to obtain.
There is no cure for HD and no way to halt its progression. Treatments are designed to relieve symptoms, minimize harm and provide comfort. The first goal is to minimize any unnecessary medications or those that may be producing side effects. Assessments by physical, occupational, and speech therapists may provide insight into the patient’s difficulties and offer helpful suggestions before medications are needed. Tetrabenazine (Xenazine®) is the only approved medication for the treatment of chorea in HD. Sedation and the possibility of triggering depression are potential side effects. Chorea may sometimes be treated with antipsychotic drugs, such as haloperidol (Haldol®). In addition to reducing the abnormal movements, they may also treat co-existing psychiatric or behavioral symptoms, such as paranoia and agitation. Side effects include sleepiness, dry mouth, and less commonly, abnormal movements. There are no treatments to slow, reverse or cure the disease.
Caregivers of individuals who have HD can take steps to help the patient with daily activities. It can be helpful to the patient to keep his or her environment as "normal" as possible.
Exercise can help the patient physically and mentally, so the person with HD should try to maintain some regular physical activity if possible.
Proper nutrition and hydration are very important because the person with HD may have trouble maintaining enough caloric or fluid intakes. For patients with HD who have difficulty swallowing or choke, a swallowing evaluation can be valuable to guide caregivers on how best to prepare foods.
Caregivers can also make use of various community resources for the person with HD, including social work services, home care services and support groups. At some point, the demands of care may exceed what the caregiver can provide and placement in a long term care facility may be required. The Huntington’s Disease Society of America (HDSA) is a national voluntary organization, with local and regional chapters, committed to educating and supporting patients and families with HD.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 11/13/2017