As outlined in Figure 2, preoperative assessment includes confirmation of AD pathology by ≥ 2 abnormal core biomarkers—for example, low CSF/plasma Aβ42 or reduced Aβ42/40 ratio, elevated phosphorylated tau (p‐tau), and/or positive amyloid positron emission tomography (PET)—together with standardized cognitive staging using MMSE, Montreal Cognitive Assessment (MoCA), CDR, and Alzheimer's Disease Assessment Scale Cognitive subscale. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.