The CRISPR–Cas9 gene editing system has been widely used in genetic engineering in the field of AD (Table 1) for the development of preclinical models, pathological gene screening and therapy (Figure 3) via specific target genes, such as APP, APOE, PSEN1, PSEN2, BACE1, glia maturation factor (GMF) and CD33. Here, APP is linked to Alzheimer disease.