While the exact cause of Parkinson’s disease is currently unknown, scientists have come up with four possible theories according to the Mayo Clinic.
There are certain genes which, when they become mutated, cause Parkinson’s disease. However, these mutated genes are very rare, except in cases where Parkinson’s runs in the family. There are also some gene variations which seem to slightly increase the risk of developing Parkinson’s.
Researchers think that there are some environmental factors and toxins which may trigger Parkinson’s disease, although they feel the increased risk is small.