Is Parkinson's Disorder genetic

Answer 1

Date updated: May 4, 2007

Content provided by MayoClinic.com In the nearly 200 years since Parkinson's disease was first described, researchers have come to understand some of the processes of this complex disorder. They now know that many of the signs and symptoms of Parkinson's disease develop when certain nerve cells (neurons) in an area of the brain called the substantia nigra are damaged or destroyed. Normally, these nerve cells release dopamine - a chemical that transmits signals between the substantia nigra and another part of the brain, the corpus striatum. These signals cause your muscles to make smooth, controlled movements. Everyone loses some dopamine-producing neurons as a normal part of aging. But people with Parkinson's disease lose half or more of neurons in the substantia nigra. Although other brain cells also degenerate, the dopamine-containing cells are critical for movement and so take center stage. Just what causes this is a subject of intense research. Scientists believe Parkinson's disease may result from a combination of genetic and environmental factors. Certain drugs, diseases and toxins also may cause symptoms similar to those of Parkinson's disease. Genetic factors

Scientists believe that genes contribute to the development of Parkinson's, but it's not yet clear whether heredity plays a major or minor role in this disease. It has been known for some time that people with a first-degree relative with Parkinson's disease, such as a parent, child or sibling, are more likely to develop the disease than are people without a family connection. Although the risk among first-degree relatives is small - less than 5 percent - it nevertheless suggests a genetic link. For that reason, scientists have focused on the rare families in which several people have Parkinson's - and that research has provided insights into the cause of the disease in general. In families with Parkinson's, researchers have identified two types of genetic causes. One involves abnormalities of alpha-synuclein, a protein that accumulates in degenerating neurons in people with Parkinson's. The other involves problems with the systems in the body that dispose of unwanted proteins. It now appears that both of these factors play a key role in the development of Parkinson's in all people. Environmental factors

People with unusual exposure to herbicides and pesticides are more likely to develop Parkinson's disease than are people who don't have this exposure. Researchers haven't yet been able to connect a specific herbicide or pesticide to the disease. Medications

A number of drugs taken for long periods of time or in excessive dosages can cause symptoms of Parkinson's disease. These include medications such as haloperidol (Haldol) and chlorpromazine (Thorazine), which are prescribed for certain psychiatric disorders, as well as drugs used to treat nausea, such as metoclopramide (Reglan, Metoclopramide HCL). The epilepsy drug valproate (Depakene) also may cause some of the features of parkinsonism, especially severe tremor. These medications do not cause Parkinson's disease, however, and symptoms disappear when the drugs are stopped. www.myparkinsonsinformation.com