In Parkinson’s disease nerve cells in a very specific region of the brain (substantia nigra) break down or die. Many of the symptoms associated with Parkinson’s result from the loss of neurons that produce dopamine, which is a neurotransmitter that helps to regulate movement. Many treatments for Parkinson’s disease work to increase dopamine levels in the brain.

Research into the causes of Parkinson’s disease is also focusing on Lewey bodies and the protein alpha-synuclein, which is found within Lewy bodies. Lewey bodies are clumps of specific substances within brain cells and are recognized as markers of the disease. Alpha-synuclein clumps within the Lewey bodies in a form that cells can’t break down. It is believed that the build-up of alpha-synuclein contributes to the cause of Parkinson’s disease.

Researchers also believe that genetic factors may sometimes play a role. While considered rare, Parkinson’s disease may result from a viral infection or through exposure to environmental toxins like carbon monoxide, pesticides, certain heavy metals or repeated head injuries. In most cases the cause of the disease is unknown, but researchers commonly believe that the interaction of genetics and environmental factors cause the disease in most people diagnosed.