Discovery and Validation of Genetic Variants Affecting Microglial Activation in Alzheimer's Disease

Eligibility Criteria

• 1. Age 50 and older at time of study entry.
• 2. Meet criteria for either a) amnestic mild cognitive impairment (single or mixed domain) or Alzheimer's disease, or b) have no cognitive impairment, based on history, exam, and neuropsychological testing.
• 3. Patients must have Clinical Dementia Rating Scale score of 0.5 or 1 at enrollment. Controls must have Clinical Dementia Rating scale score of 0 at enrollment.
• 4. Subjects must have AD biomarker previously obtained for research or clinical purposes or undergo a 18F-florbetaben PET scan during the screening process. Patients must have positive amyloid PET scan or CSF results consistent with AD. Controls must have a negative amyloid PET scan or CSF results not consistent with AD.
• 5. Self-identify as white, non-Hispanic or Latino
• 6. Subjects must be ableto provide informed consent
• 7. Written and oral fluency in English
• 8. Able to participate in all scheduled evaluations and to complete all required tests and procedures.
• 9. In the opinion of the investigator, the subject must be considered likely to comply with the study protocol and to have a high probability of completing the study.
• 1. Past or present history of certain brain disorders other than MCI or AD.
• 2. Certain significant medical conditions, which make study procedures of the current study unsafe. Such serious medical conditions include uncontrolled epilepsy and multiple serious injuries.
• 3. Contraindication to MRI scanning
• 4. Conditions precluding entry into the scanners (e.g. morbid obesity, claustrophobia, etc.).
• 5. Exposure to research related radiation in the past year that, when combined with this study, would place subjects above the allowable limits.
• 6. Participation in the last year in a clinical trial for a disease modifying drug for AD.
• 7. Inability to have a catheter in subject's vein for the injection of radioligand.
• 8. Inability to have blood drawn from subject's veins.
• 9. Taking anticoagulant (e.g., warfarin) or immunosuppressive/immunomodulatory medication. Nonsteroidal anti-inflammatory drugs (NSAIDs) are not exclusionary. Use of steroids in the 30 days preceding the PET scan.
• 10. Having a diagnosis of a chronic inflammatory disease (for example, multiple sclerosis, inflammatory bowel disease, rheumatoid arthritis, psoriasis, systemic lupus erythematosus) or a chronic infectious disease such as H.I.V.