Huntington's Disease (Chorea)

What Is It?

Huntington's disease is an inherited disease that causes nerve cells in the brain to stop working properly. It is a progressive disease, meaning it continues to get worse over time. It leads to mental deterioration and loss of the ability to control major muscle movements.

An American doctor, George Huntington, first described the disease in 1872. It was commonly called Huntington's chorea from the Greek word for "dance," because of the jerky, almost dancelike movements of people with the disease.

The genetic abnormality that causes Huntington's disease was discovered in 1993. Each child of a parent with Huntington's disease has a 50% chance of inheriting the illness. (Doctors call this an autosomal dominant disorder.) Huntington's disease is relatively uncommon, affecting about 30,000 people in the United States. It affects people from all ethnic groups, and it affects males and females equally.

Symptoms

Huntington's disease can affect intellectual ability, movement and emotional control. Symptoms include:

• Memory loss, inattention, dementia
• Involuntary twitching, clumsiness, dancelike involuntary movements (chorea), slurred speech, difficulty walking, difficulty swallowing
• Personality changes, depression, irritability, anxiety or lack of emotions (apathy)

Symptoms vary from person to person. They also can change over time, usually starting as subtle differences and progressing to profound disability. Symptoms typically begin between ages 35 and 50, though they can appear at any age.

The disease is rare in children. Symptoms begin before age 20 in less than 5% of cases. This is called juvenile Huntington's disease. In children with Huntington's disease, behavioral problems and mental deterioration are prominent, and rigidity and seizures are common. Huntington's disease progresses more rapidly in children than in adults.

Diagnosis

Because the symptoms of Huntington's disease begin subtly, diagnosis may not be made until the disease has started to worsen. Someone with a family history of Huntington's disease who begins to have symptoms often is diagnosed based on a physical and neurological exam. A blood test is now available to detect the genetic abnormality that causes Huntington's disease. Everyone who carries the Huntington's disease gene eventually will develop the disease, but the test cannot predict when symptoms will begin.

Genetic testing carries enormous emotional and practical consequences, so you should discuss these issues with your doctor. Some people choose to be tested so they can make informed decisions about future plans (for example, career or marriage). Some hospitals offer prenatal testing. If you have a family history of Huntington's disease, you can seek genetic counseling before getting pregnant to determine your risk of passing the gene to your children.

Many experts recommend that children under 18 should not get a genetic test, except in rare cases where there is an urgent medical need to do so. It is better to wait until children turn 18 so they can decide if they want to learn if they have the gene for Huntington's.

Expected Duration

The genetic abnormality that causes Huntington's disease is present from birth. Symptoms typically begin in mid-life and last until the end of life.

Prevention

There is no way to prevent this disease in people who have inherited the genetic abnormality.

Treatment

There is no treatment to cure Huntington's disease or slow its progression. However, there are therapies, including speech therapy and physical therapy, that can lessen the severity of symptoms. Antidepressants, neuroleptics and other medications can help to control mood and involuntary movements.