Late Onset Alzheimer's Disease

Inclusion criteria

• Established diagnosis of definite or probable AD or have a diagnosis of a related neurodegenerative disorder such as Frontotemporal Dementia (FTD) or Lewy Body Dementia (LBD) (will also recruit sporadic FTD and LBD) cases.
• a living sibling with probable or possible AD;
• a third living relative affected with AD (onset age 50 or older) or unaffected (60 or older);
• participants in the proband's generation with an identified companion serving as an informant;
• participants who have capacity to consent or participants lacking capacity to consent with a surrogate/proxy in place to provide consent.

Exclusion criteria

• failure to identify an appropriate informant;
• uncertainty of the clinical diagnosis of Alzheimer's disease or other related disorder;
• discovery of additional diagnosis that could account for the clinical manifestations;
• unwillingness to participate;
• failure to identify a living sibling with AD or other related disorder (except in the cases of sporadic FTD and sporadic LBD);
• participants lacking the capacity to consent who do not have a surrogate or proxy or next of kin to provide consent.