Accurate AD diagnosis requires a comprehensive, multimodal approach integrating clinical assessments, medical imaging (MRI, PET), biomarkers (CSF, blood), and genetic risk analysis (e.g., APOE\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\varepsilon $$\end{document}4). The gene discussed is APOE; the disease is Alzheimer disease.