APP and early-onset autosomal dominant Alzheimer disease: Alzheimer's disease is a common neurodegenerative disease, mainly characterized by excessive abnormal phosphorylation of Tau protein, thus leading to the formation of neurofibrillary tangles (NFT) and senile plaques (SP) caused by APP protein metabolic disorders, free radical damage, and nerve cell apoptosis [15], which further results in cognitive impairment.