factors. We are not aware of any other dataset with a similar study design to the densely affected COGA families. This lack of a well-matched study design was the main reason we did not attempt to replicate the strongest signals. The lack of direct replication is one of the biggest limitations of the study, but the linkage signal on chromosome 3 in EAs and AAs families provides some additional support for an AD risk locus in this region. Nonetheless the current study provides a well-characterized dataset that can be used in genome-wide meta-analysis of AD or age at onset of AD.
