APOE and Alzheimer disease: Longitudinal studies have identified multiple predictors of progression to dementia, including lower baseline memory performance, involvement of multiple cognitive domains, positive AD biomarkers (amyloid and tau), APOE ε4 genotype—especially ε4/ε4—neuropsychiatric features such as depression, apathy, and anosognosia, imaging markers such as hippocampal atrophy or temporoparietal hypometabolism, low cognitive reserve, and uncontrolled vascular risk factors [10,11,12,15].