In APP/PS1 mice and post-mortem human brains of AD patients, Rac1 activity was upregulated, most likely induced by Aβ peptides (Wu et al., 2019), and other studies have further suggested that heightened Rac1 activation correlates with rapid memory loss and is age-dependent (Zhang et al., 2021b). This evidence concerns the gene RAC1 and Alzheimer disease.