APOE and Alzheimer disease: Recommendations: (1) a review of disease history and comprehensive assessment of ABC symptoms should be the basis for AD diagnosis; (2) imaging examinations, including MRI structural imaging, cerebral PET, and SPECT, can be auxiliary examinations for diagnosing AD; and (3) biomarker examinations, including screening for the apolipoprotein E ε4 gene and measuring Aβ and Tau, can be conducted if possible.