<i>APOE</i> Alleles Modify Symptom Onset in Early‐Onset Alzheimer's Caused by the <i>PSEN1</i> A431E Mutation

This study highlights an apparently inverse effect of APOEε4 and APOEε2 in EOAD patients with the PSEN1 A431E mutation, compared to late-onset AD. Specifically, APOEε4 delays the age of symptom onset, whereas APOEε2 accelerates it. These findings suggest that APOE alleles play a dual role as genetic modifiers in EOAD, offering potential avenues for personalized risk assessment and targeted interventions.