RecruitingDrug trialLongitudinal Early-onset Alzheimer's Disease Study ProtocolThe Longitudinal Early-onset Alzheimer's Disease Study (LEADS) is a non-randomized, natural history, non-treatment study designed to look at disease progression in individuals with early onset cognitive impairment. Clinical, cognitive, imaging, biomarker, and genetic characteristics will be assessed across three cohorts: (1) early onset Alzheimer's Disease (EOAD) participants, (2) early onset non-Alzheimer's Disease (EOnonAD) participants, and (3) cognitively normal (CN) control participants.