RecruitingDrug trialA Study of Potential Disease Modifying Treatments in Individuals at Risk for or With a Type of Early Onset AD Caused by a Genetic MutationThe purpose is to evaluate the biomarker effect, safety, and tolerability of investigational study drugs in participants who are known to have an Alzheimer's disease (AD)-causing mutation. Stage 1 will determine if treatment with the study drug prevents or slows the rate of amyloid beta (Aβ) pathological disease accumulation demonstrated by Aβ positron emission tomography (PET) imaging. Stage 2 will evaluate the effect of early Aβ plaque reduction/prevention on disease progression by assessing downstream non-Aβ biomarkers of AD (e.g., CSF total tau, p-tau, NfL) compared to an external control group from the DIAN-OBS natural history study and the DIAN-TU-001 placebo-treated participants.