Ancillary Longitudinal CSF Collection Study in the Harvard Biomarker Study - HBS2

Inclusion Criteria for Cases with PD: - Age ≥ 21 - UK Parkinson's Disease Society Brain Bank criteria or movement disorder specialist diagnosis of PD - Hoehn & Yahr stage ≤ 3.0 - Mini Mental State Exam score >21 OR authorized legal guardian available to sign consent - Able to provide informed consent Inclusion Criteria for Controls: - Age ≥ 21 - Absence of any neurological disease - No family history of a first-degree relative with PD - Mini Mental State Exam score >21 OR authorized legal guardian available to sign consent - Able to provide informed consent Exclusion Criteria for Cases and Controls: - Acquired or inherited bleeding disorders - Hematologic malignancies - Hematocrit < 30 - Active ulcer or active colitis - Known pregnancy - Clinical contraindications to lumbar puncture (including: known mass lesion of the CNS or evidence for raised intracranial pressure on fundoscopic exam; abnormal coagulation tests; platelet count < 50,000; subject on warfarin (coumadin), heparin, dabigatran, rivaroxiban or apixaban; subject on both aspirin and clopidogrel (Plavix); infection near the LP site or spinal deformity; known allergy to lidocaine)