1. Male or female.
2. Any ethnic or racial group.
3. Age >= 20 years.
4. Diagnosed by a knowledgeable clinician as having probable idiopathic Parkinson’s disease or another degenerative parkinsonian disorder (normal controls can also be enrolled).
5. The subject or appropriate representative provides informed consent for data to be transferred to the PD-DOC.
6. Data obtained and submitted by an approved PD-DOC user (investigator).

The following should be requested from each enrolled subject:

1. Completion of the full PD-DOC Core Data Set.
2. A blood sample for submission to the NINDS Genetics Repository.
3. Consideration of brain donation at the time of death for neuropathologic examination. Information about the procedures for brain donation should be provided to each subject/family.