One major argument in favor of the more prominent involvement of Abeta in the pathogenesis of AD, in contrast to Tau, is its higher specificity to AD and its appearance in the early familial variants of AD, where the molecular pathway is better understood (Blennow et al., 2006; Klunk et al., 2007; Villemagne et al., 2009). This evidence concerns the gene APP and Alzheimer disease.