HUNTINGTON'S CHOREA

Huntington's chorea is a degenerative disease of the brain. Huntington's chorea involves the parts of the brain responsible for movement, thinking, memory, perception, and intelligence. Statistics from the National Institute of Health report that in the United States approximately 30,000 people have this disease and at least 150,000 other people have a 50% chance of developing the disease.

Huntington's chorea is an inherited disorder, meaning it is passed on from generation to generation. The specific cause is a genetic mutation located on chromosome 4. A genetic mutation means there was an error in the building blocks that make up the gene. These building blocks are called nucleotide bases, and they form the large molecule known as DNA (deoxyribonucleic acid). It is the DNA that carries the genetic information of life. The DNA sequence of a gene is responsible for the transcription of proteins. In Huntington's chorea, the mutation of the gene on chromosome 4 leads to the excess production of the protein called huntingtin. Although still in the research stages, it is thought that this protein causes cellular death to certain parts of the brain by a mechanism not yet understood. It is this loss of brain cells that leads to the signs and symptoms found in Huntington's disease described below.

In 1993 the gene causing Huntington's disease was discovered. It is now possible to perform direct genetic testing to confirm the diagnosis of Huntington's disease.

Huntington's disease can occur anytime between the ages of 2 to 70 years but usually is detected in early adulthood between the ages of 30 to 40 years. Uncontrolled movements called chorea (described as a twisting dancelike motion usually starting in the feet, fingers, face, or upper thorax), unsteadiness, clumsiness, loss of balance, slurred speech, and difficulty swallowing and eating are other symptoms seen in patients with Huntington's disease. Anger, mood swings, irritability, decreased memory, and poor judgment are some of the emotional and cognitive impairments that can also occur.

Not all patients have these exact symptoms. Some patients may develop the disease at a much younger or older age and may appear rigid with little movement or have fine twitching with tremors.

Unfortunately, the disease is progressive, meaning slow deterioration of motor and cognitive skills will continue. This can ultimately result in death, most commonly from pneumonia or complications from injuries.

There is no treatment available that will reverse Huntington's disease. Antidepressant medications including sertraline, fluoxetine, amitriptyline, and nortriptyline can be used in situations of known depression. Lithium can be used for extreme mood swings (bipolar), and antianxiety pills can be used for the general anxiety disorder.

Antipsychotic drugs (haloperidol) or benzodiazepines (e.g., diazepam or clonazepam) may be helpful for the movement disorder.

• Understand that Huntington's disease is an inherited genetic disease. When a family member is diagnosed with Huntington's disease, the anxiety of knowing or not knowing if you have the Huntington's disease gene can become overwhelming. Each child of a patient with Huntington's disease carries a 50-50 chance of inheriting the Huntington's disease gene.
• Remember that, although controversial, there are genetic markers or tests that can be done to identify if you are carrying the Huntington's gene or not. The decision to have this test knowing there is no treatment and understanding the nature of this progressive deteriorating disease will not be an easy one.
• Refer to the testing guidelines provided by the Huntington's Disease Society of America (HDSA). See below for more information.

• Don't forget that patients with Huntington's disease need a team of caregivers. The best person from whom to seek advice is the neurologist (physician specializing in diseases of the brain and spinal column). Physical therapy, occupational therapy, psychiatry, and social workers can all offer assistance in the short- and long-term management of patients with Huntington's disease.
• Don't be afraid to ask for more information. If you are thinking of being tested for Huntington's disease, be aware of the increased risk of loss of health and life insurance if the test is positive.

• If any member of your family has been diagnosed with Huntington's disease.
• If you need information on referral centers for patients with Huntington's disease.

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