Huntington’s disease is an inherited disorder that causes degeneration of a particular part of the brain. Also known as Huntington’s chorea, the condition causes jerky, involuntary movements, clumsiness, and progressive dementia. Huntington’s disease is rare, affecting only about 6,000 people in the UK. The symptoms commonly develop between the ages of 30 and 50.
Huntington’s disease is caused by an abnormal dominant gene. To develop the disease, an affected person has to inherit the abnormal gene from only one parent. People who have the gene have a 1 in 2 chance of passing it on to each of their children. Since the symptoms do not develop until later in life, an abnormal gene may be passed on to children before the affected parent becomes aware that he or she has Huntington’s disease. However, a genetic test can be carried out at any age to find out if an individual has inherited the abnormal gene from a parent.
What are the symptoms?
Symptoms develop gradually over a period of months or years. Initially, they may include the following:
- Jerks and spasms of the face, arms, and trunk.
- Clumsiness.
- Mood swings, including outbursts of aggressive, antisocial behaviour.
- Poor memory, especially for events that have occurred recently.
As the disease progresses, further symptoms of dementia, such as losing the ability to think rationally, may develop. There may be difficulty in speaking and swallowing, and problems with urinary incontinence. Anxiety and depression may also occur.
What might be done?
Unless the condition has already been diagnosed within the family, it may not be recognized during its early stages. Usually, a member of the affected person’s family first realizes that there is a problem. The affected person may be suspicious of others and refuse help. Diagnosis is usually made from the symptoms and by CT scanning or MRI of the brain, which may show distinct patterns of abnormality.
There is no cure for Huntington’s disease, bur drugs may relive certain symptoms. For example, antipsychotic drugs help to control jerks and spasms. Speech therapy and occupational therapy are used to help an affected person to lead as normal a life as possible. However, care in a nursing home may be necessary if the person is unable to live at home or when carers need a period of respite. Members of the family may decide to have a blood test to determine whether they have the abnormal gene themselves. These tests are performed after genetic counseling because the results are likely to have a bearing on whether or not they decide to have children.
Huntington’s disease has a slow progression. A person may live for 15-20 years after the onset of symptoms.