APP and Alzheimer disease: As accumulation of Aβ is a major specific hallmark of AD, studies on AD have widely focused on the generation of hPSC-derived neurons from sporadic or familial cases with mutations in the genes associated with Aβ production (APP, PSEN1, or PSEN2) assessing whether aberrant accumulation of Aβ can be reproduced in vitro and assessing its functional consequences and/or suitability in the platform for drug assessment.