In addition, the ADNI cohort represents a sample typical of a clinical trial for MCI/AD and the analyses here were restricted to non-Hispanic Caucasians. The extent to which the present findings can be generalized to other populations and to the community setting of MCI/AD individuals remains to be determined. Future multi-center and international collaborations are expected to yield larger samples with greater power for analyses of potential interactions of genetic risk factors with each other and with clinical variables such as gender, ethnicity, family history, age of onset, and rate of disease progression, which could not be appropriately addressed with presently available data. Florbetapir also does not bind soluble forms of Aβ45 which may exhibit dynamic relationships with deposited, fibrillar Aβ to drive neurodegeneration in AD.1 Finally, while this study employed imputed (probabilistically-predicted) genotype data to provide deep coverage of the genome, higher-density genotyping arrays and sequencing will eventually provide direct assays for a similar number of variants.
