Late Onset Alzheimer's Disease

This study is researching the genetics behind late-onset Alzheimer's disease and related memory disorders. Researchers want to understand why these diseases run in families by studying patients alongside their relatives. **You may be eligible if...** - You have been diagnosed with Alzheimer's disease, Frontotemporal Dementia (FTD), or Lewy Body Dementia - You have a living sibling who has probable or possible Alzheimer's disease - You have at least one more relative with Alzheimer's disease (who got it at age 50 or older) or an unaffected relative aged 60 or older - You have a close companion or family member who can serve as an informant - You can consent yourself, or have a family member who can consent on your behalf **You may NOT be eligible if...** - No appropriate informant (someone who knows you well) can be identified - Your diagnosis is uncertain - Another condition could explain your symptoms - You are unwilling to participate - You have no living sibling with Alzheimer's or a related disorder (unless your diagnosis is sporadic FTD or sporadic LBD) Talk to your doctor to see if this trial is right for you.