Parkinson’s disease causes the death of the cells that produce dopamine located in the substantia nigra, which is part of the basal ganglia.
The cause of these changes is largely unknown.
The key change found in the brain of someone with PD is the presence of Lewy bodies. In Parkinson’s disease a protein called alpha synuclein misfolds and goes on to form large clumps or Lewy bodies, which disrupt the normal functioning of the brain.
It is thought that a combination of genes, environmental and lifestyle factors determines if someone will develop PD.
Genetics
Genetics explains about 10% to 15% of cases. Familial PD where the faulty gene is passed down through the generations is rare. Scientists have discovered many gene mutations that are linked to PD but they are still to determine how these mutations contribute to this disorder. Having one of the genetic mutations does not mean the person will go on to develop PD.
Environmental risk factors
Studies that have investigated the relationship between PD and occupations, exposure to metals and certain chemicals have been inconsistent in their findings. A strong link has been found, however, between exposure to certain pesticides and herbicides and PD.
Protective factors
Studies have suggested that certain factors may decrease the risk of developing PD. Being regularly physically active early in life appears to lower the risk of developing PD. It is less clear if other factors such as anti-inflammatory drugs, statins, caffeine, or high vitamin D levels, also reduce the risk.