Parkinson’s disease is a neurodegenerative disorder that currently affects at least 500,000 people in the United States, although some estimates are much higher. The average age of onset is about 60 years, and as a greater proportion of the U.S. lives longer, disease prevalence is expected to increase.
Parkinson’s disease progresses slowly as small clusters of neurons in the midbrain die. The gradual loss of these neurons reduces levels of the chemical dopamine, which is responsible for transmitting messages to the parts of the brain that coordinate muscle movement. Common symptoms include tremors or shaking in 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 of Parkinson’s disease begin gradually and typically worsen over time.
While scientists do not know the exact cause of Parkinson’s disease, most agree that the combination of a person’s genes, environment, and the interaction between these two factors 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 develop approaches to prevent, diagnose, and treat the disease.
NIEHS-funded scientists use new models and approaches to study both the genetic and environmental risk factors of Parkinson’s disease. They are investigating how diet, exercise, pesticides, and other environmental factors, might increase or decrease a person’s risk for developing Parkinson’s disease. Researchers are also examining how genetic variation may make some more likely to develop the disease, and how certain genes can mediate a person’s response to environmental risk factors.
Jonathan A. Hollander, Ph.D.
Health Scientist Administrator