Several studies have shown a correlation between manganese and Parkinson’s symptoms.
Manganese (not the more familiar magnesium) is a metal. It is essential in many of the body’s processes; however, too much can cause manganism. Interestingly, it is believed that a genetic mutation (in the SLC30A10 gene) may play a role. In addition, no Lewy bodies are seen in this disease.
The following article is a great summary of some of the findings:
“Manganese Exposure May Be Linked to Parkinson’s Development, Study Suggests”