Parkinson’s disease is a neurodegenerative disorder that currently affects nearly one million people in the United States, although some estimates are much higher. The average age of onset is about 60 years, and as more Americans live longer, disease prevalence is expected to increase.
Parkinson’s disease progresses slowly as small clusters of brain cells called neurons die. The gradual loss of those neurons reduces levels of a chemical called dopamine that transmits messages to the parts of the brain that coordinate muscle movement. Common symptoms of Parkinson’s disease include tremors or shaking in the hands, arms, legs, jaw, and face; rigidity or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and difficulties with balance, speech, and coordination. Symptoms begin gradually and typically worsen over time.
Although scientists do not know the cause of Parkinson’s disease, most agree that interaction between a person’s genes and environment play a role in disease onset and progression. By identifying the environmental exposures associated with Parkinson’s disease and understanding the biological processes that dictate how the disease develops and progresses, scientists can devise approaches to prevent, diagnose, and treat the disease.
NIEHS-funded researchers study the genetic and environmental risk factors of Parkinson’s disease. Specifically, they are investigating the role of diet, exercise, and pesticides, among other environmental factors. Researchers are also examining how genetic variation may make some people more prone to the disease, and how certain genes can affect a person’s response to environmental risk factors.
Jonathan A. Hollander, Ph.D.
Health Scientist Administrator