Parkinson’s Disease
Parkinson’s disease is a progressive, degenerative movement disorder that destroys nerve cells in the part of the brain responsible for muscle control and movement. Parkinson’s disease patients usually have difficulty walking and maintaining balance, and symptoms worsen over time. There is no cure, but treatment options – such as medication and surgery – are available to help manage symptoms.
The manifestation of Parkinson's disease at the clinical level occurs when a group of cells in an area of the brain called the substantia nigra begin to malfunction and die. These cells in the substantia nigra produce a chemical called dopamine, which is a neurotransmitter – or chemical messenger – that sends information to the parts of the brain that control movement and coordination.
When a person has clinical symptoms of Parkinson's disease, their dopamine-producing cells have greatly degenerated and the amount of dopamine produced in the brain decreases. Messages from the brain telling the body how and when to move are delivered more slowly, leaving a person incapable of initiating and controlling movements in a normal way.
Parkinson’s disease is a complex disorder and its causes may involve several factors. In recent years, human genetic studies have identified specific genetic changes that can lead to altered proteins, and subsequently Parkinson’s disease. One such altered gene is alpha-synuclein. The normal function of alpha-synuclein is unknown, but it can become modified under pathological conditions and form abnormal fibrils and inclusions known as Lewy bodies in brain tissue. Information from genetic studies, including those involving alpha-synuclein, provide important information to help guide scientists to find a way to stop the disease.
Statistics
It is estimated that between 1 million and 1.5 million people in the U.S. are living with Parkinson's disease. The cause is unknown, but experts have identified aging as a factor that contributes to Parkinson’s disease in some individuals. The condition usually develops after age 65. For example, people over age 60 have a 2% to 4% percent risk of developing Parkinson's disease, compared with a 1% or 2% risk in the general population. But an estimated 15% of patients are diagnosed before age 50.
Some families share a gene that leads to Parkinson’s disease, but this is a small percentage of the population. In most Parkinson’s disease cases, genetics and family history have not played a clear role in the onset and development of the disease. Scientists believe that only about 5 percent of patients have an inherited form of the disease. Genetics and environmental factors are believed to play a role in the onset of Parkinson’s disease.
Symptoms
Parkinson's disease symptoms vary from patient to patient. Some of the most common symptoms of Parkinson's disease are tremor of the hands, arms, legs, jaw and face; rigidity or stiffness of the limbs and trunk; slowness of movement (bradykinesia); postural instability or impaired balance and coordination.
Some scientists have suggested that Parkinson's disease may result from exposure to an environmental toxin or injury. There is no conclusive evidence, however, that any single environmental factor can be considered a cause of the disease.
Can Parkinson’s Disease be Treated?
There are medications available to treat the symptoms of Parkinson’s, although none reverse the effects of the disease. In addition, doctors have attempted to treat Parkinson’s disease with surgery for more than 50 years. The current standard surgery, deep brain stimulation (DBS), was developed in the 1990s and has been used to treat about 30,000 people worldwide.
Resources
Parkinson’s Disease Foundation
Michael J. Fox Foundation for Parkinson’s Research
National Parkinson Foundation
