Risk Factors. PD is an idiopathic syndrome. There is an autosomal-dominant form of parkinsonian syndrome related
to a genetic defect of chromosome 4. Environmental factors contributing to PD include postencephalitic parkinsonism,
drug-induced toxin-induced parkinsonian syndrome, exposure to agriculture pesticides and herbicides, and trauma to the midbrain. Other related causes include hydrocephalus, hypoxia, infections, stroke, tumor, and traumas .