Causes of Parkinson’s disease 1. Decrease in dopamine. (Age-related Parkinson’s disease) The most important pathological change in Parkinson’s disease is the degenerative death of dopaminergic neurons in the substantia nigra of the midbrain, resulting in a significant decrease in striatal DA content and causing the disease. Degenerative lesions. 2. Gene mutation, genetic. (Youth-type Parkinson’s disease) The prevalence of PD in people over 65 years of age in China is about 1.7%. Most patients with Parkinson’s disease are disseminated cases, and only less than 10% of patients have a family history. Rarely, multiple cases in families, and environmental factors such as exposure to certain chemicals such as MPTP certain pesticides heavy metals (manganese) can cause Parkinson’s disease.