APP and early-onset autosomal dominant Alzheimer disease: In contrast to the dense-cored Aβ-plaques, which are typically observed in transgenic AD mouse models and consist mainly of Aβ-fibrils (Sasaguri et al., 2017), the Aβ-deposits in APP knock-in mouse mice consist predominantly of loosely bound prefibrillar Aβ-oligomers (Sacher et al., 2019), which are similar in their composition to human Aβ-deposits in early stage of Alzheimer's disease (Saido et al., 1995; Sasaguri et al., 2017).