This research is exploring how inflammation (swelling and irritation) might play a role in Parkinson's Disease (PD) and Alzheimer's Disease (AD). The study involves up to 2 visits where participants will answer short questions and have some blood drawn. The researchers are looking for three groups: people with PD, people with AD or mild memory problems, and healthy people of the same age. Blood donation can be done at the clinic or at home, with a mobile phlebotomist (a person trained to take blood). They want to see if certain proteins in the body might be causing these diseases.

• The study requires up to two visits, with options for smaller blood donations or at-home visits.
• Participants must be at least 55 years old and willing to have genetic tests.
• People with recent cancer, autoimmune diseases, or certain medications cannot participate.