APOE and Alzheimer disease: Although not all studies agree on the impact of apolipoprotein (APOE) ε4 on MCI (Heun et al., 2010), MCI is commonly considered a prodrome for AD (Albert et al., 2011), and APOE ε4 is one of the strongest genetic risk factor for sporadic late-on-sent AD (Polsinelli et al., 2023).