APP and Alzheimer disease: In another exciting study, Park et al. (2019) targeted beta-secretase 1 “Bace1” gene (which is required for the production of Aβ peptides) through CRISPR/Cas9-loaded nanocomplexes in post-mitotic neurons in vivo and demonstrated their therapeutic application in five familial AD (5XFAD) and APP knock-in AD mouse models.