APOE4 is the strongest genetic risk factor for sporadic, late-onset AD, with a 3-5-fold higher risk of AD in people with one copy of APOE4 and a more than 10-fold higher risk for people with 2 copies of the gene (Corder et al., 1993; Farrer et al., 1997; Mahley and Huang, 2012; Neu et al., 2017; Belloy et al., 2019; Fortea et al., 2024). The gene discussed is APOE; the disease is Alzheimer disease.