 In this study, the PDx assay will be designed and validated in order to distinguish between Idiopathic Parkinsons disease PD to patients with similar symptoms and healthy controls. The differential diagnosis cohort includes patients diagnosed with Multiple System Atrophy MSA, Progressive Supranuclear Palsy PSP, Corticobasal Degeneration CBD, Essential Tremor ET or Lewy Body Dementia LBD and Healthy Controls. 