Parkinson's disease occurs when brain cells that produce an important hormone called dopamine begin to die off or become impaired. As dopamine levels decrease, people develop movement symptoms like shaking or stiffness, as well as problems maintaining balance and coordination.

Parkinson's disease is a neurogenerative disease that affects more than 1 million people in the U.S. While some cases are caused by genetics, the cause is unknown in most.

Groundbreaking new research released from Northwestern Medicine discovered that a usually harmless virus in the blood, may be triggering Parkinson's disease.