The UCLA Alzheimer's Disease Research Center (ADRC) Clinical Core has made substantial contributions towards defining the phenotypes of the Alzheimer’s diseases and other dementing illnesses, critical steps in developing interventions to treat or prevent these increasingly common neurodegenerative illnesses. The purpose of the Clinical Core at UCLA is to establish and characterize a cohort of persons at-risk for or affected by late- and young-onset forms of dementia. This includes those with familial AD (FAD) due to fully penetrant autosomal dominant mutations, and persons with sporadic AD, frontotemporal lobar degeneration (FTLD)-spectrum diseases, and Lewy Body pathology (Parkinson’s disease and dementia with Lewy Bodies). This cohort undergoes exhaustive clinical assessments and, through interactions with the other cores, genetic, plasma biomarker, and in some cases, imaging, cerebrospinal fluid (CSF), and neuropathological characterization. We have established a database that allows for analyses across these datasets and diagnostic groups.