Inclusion criteria: Patients must be 18 years of age or older. Must fulfill WHO Revised Criteria for CJD[1], have a family history of familial human prion disease, or have a history of progressive neurologic decline resulting in dementia or significant functional impairment from patient's baseline over two years or less from symptoms onset. Must have an informant who has frequent contact with the subject and is available to provide information about the subject.
Exclusion criteria: Unable to undergo MRI due contraindication to this procedure (e.g., pacemaker, pregnant women). Known HIV positive or immunosuppressed patients.
