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, and leads to mental deterioration and loss of the ability to control major muscle movements.

An American doctor, George Huntington, first described Huntington's 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. Huntington's disease is transmitted as an autosomal dominant disorder, meaning that each child of a parent with Huntington's disease has a 50-percent chance of inheriting the illness. Huntington's disease is relatively uncommon, affecting about one in every 10,000 people, or approximately 30,000 people in the United States.

Symptoms

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

• Memory loss, inattention, dementia
• Involuntary twitching, clumsiness, chorea (dance-like involuntary movements), slurred speech, difficulty walking, difficulty swallowing
• Personality changes, depression, irritability, anxiety, 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 the ages of 35 and 50, though they can appear at any age.

The disease is rare in children. Symptoms begin before age 10 in less than 1 percent of cases. In children with Huntington's disease, behavioral problems and mental deterioration are prominent, and rigidity and seizures are also common. Huntington's disease progresses more rapidly in children than in adults.

Diagnosis

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 presence of 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, and you should discuss these issues with your doctor. Some people chose to be tested in order to make informed decisions about future plans (for example, career or marriage). In some centers, prenatal testing can be done. If you have a family history of Huntington's disease, you should seek genetic counseling before getting pregnant to determine your risk of passing the gene to your children.