This result is of great significance for the diagnosis and prevention of early AD, but it has limited value in distinguishing other types of dementia: some scholars reported in the early research that the specificity of APOE ε4 detection in distinguishing ad-induced dementia and other types of dementia is only 23%-88% [26], so it is necessary to combine other detection methods to exclude other factors that caused dementia. The gene discussed is APOE; the disease is Alzheimer disease.