The AD neuropathological phenotype observed in individuals with DS, which includes Aβ deposition (parenchymal and vascular) and neurofibrillary tangles (NFTs), is like that described in patients with AD10,19,20; however, variations between AD in DS and AD caused by AβPP locus duplications have been reported, suggesting that additional genes/factors may modulate the development of AD in DS19. Here, APP is linked to Alzheimer disease.