APP and Alzheimer disease: Furthermore people with DS having more than 100x risk of developing AD compared to rest of population, again largely thought to be due overexpression of APP and other chromosome 21 genes like DYRK1A throughout development and adulthood, leading to AD pathology including amyloid plaques and Tau tangles in young adults (Zigman, 2013; Wiseman et al., 2015; Selkoe and Hardy, 2016).