Indeed, many mouse models of Alzheimer's disease (AD), such as Presenilin-1 with both M146V and ΔExon9 mutations in knock-in mice and transgenic mice with the Swedish APP mutation, showed decreased adult neurogenesis (Wang et al., 2004; Zhang et al., 2007; Choi et al., 2008). Here, PSEN1 is linked to early-onset autosomal dominant Alzheimer disease.