In the context of the high risk for AD in DS, it is important to note that the amyloid precursor protein (APP) gene located on HSA21 is also triplicated in Ts65Dn mice, but that the APP cleavage product amyloid-beta (Aβ) does not accumulate into plaques in Ts65Dn mice like in the human condition (Gardiner, 2015, Reeves et al., 1995). This evidence concerns the gene APP and Alzheimer disease.