Huntington's disease (Huntington's chorea) is a progressive, degenerative disease that causes certain nerve cells in your brain to waste away. As a result, you may experience uncontrolled movements, emotional disturbances and mental deterioration. The disorder was documented in 1872 by American physician George Huntington. The name chorea comes from the Greek word for "dance" and refers to the characteristic and incessant quick, jerky, involuntary movements.

Huntington's disease is an inherited condition resulting from a single abnormal gene. Signs and symptoms usually develop in middle age, and men and women are equally likely to develop the disease. Younger people with the disease often have a more severe condition and symptoms may progress more quickly. Rarely, cases may occur in children.

Signs and symptoms

Signs and symptoms of Huntington's disease may include:

• A wide, prancing gait

• Hesitant, halting or slurred speech

• Jerky, involuntary movements of your fingers, feet, arms, neck, trunk and face

• Clumsiness or problems with balance

• Personality changes (moodiness, paranoia)

• Memory loss, inattention (intellectual deterioration)

The disease usually develops slowly, and the severity of signs and symptoms is related to the degree of nerve cell loss. Personality changes may occur first. Involuntary facial movements may begin subtly and develop into grimaces. Other signs and symptoms, including severe chorea and mental impairment (dementia), appear as the disease progresses. Death occurs about 10 to 30 years after signs and symptoms first appear.

Causes

Huntington's disease is an inherited condition caused by a single abnormal gene. Doctors refer to the illness as an autosomal dominant disorder because only one copy of the defective gene, inherited from either parent, is necessary to produce the disease. If one parent has the single faulty gene, the chance that an offspring will have the defect is 50 percent. Because signs and symptoms typically appear in middle age, some parents may not know they carry the gene until they've already had children and possibly passed on the trait.

If your child doesn't inherit the faulty gene, he or she won't develop Huntington's disease. Everyone who has the gene eventually develops Huntington's disease, if he or she lives long enough.

Risk factors

If one of your parents has Huntington's disease, you have a 50 percent chance of developing the disease. In rare cases, you may develop Huntington's disease without having a family history of the condition. Such an occurrence may be the result of a genetic mutation that happened during your father's sperm development.

When to seek medical advice

See your doctor if you notice changes in your movements, emotional control or mental ability. These signs and symptoms can be the result of many conditions, so they don't necessarily mean you have Huntington's disease.

If you have a family history of Huntington's disease, you may want to talk with your doctor. Some people choose to undergo genetic testing to determine whether they carry the defective gene.

Deciding whether to be tested for the gene is a personal decision. For some people, the uncertainty of whether they carry the faulty gene is stressful and distracting. For others, the knowledge that they will develop the condition is burdensome. If you choose to be tested, consider paying for it with your own money so that the test results remain in your control.

Screening and diagnosis

To determine whether you may have Huntington's disease, your doctor performs a physical exam and obtains your and your family's medical histories. He or she may also ask about any recent emotional or intellectual changes you have had. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan may show any changes to your brain's structure. Your doctor may suggest a blood test to determine whether you carry the defective gene.

Complications

After onset of the disease, signs and symptoms continue until death. Though the signs and symptoms vary from person to person, vital functions such as swallowing, eating, speaking and walking may degenerate over time. Death is often the result of infection, injury from a fall or other complications.