In AD, it is well known that the APOE e4 allele (APOE4) is associated with increased amyloid-ß, rapid cortical thinning1, and accelerated cognitive decline2, while the APOE e2 allele (APOE2) is associated with less amyloid-ß3, slower cortical thinning4, and slower cognitive decline3. The gene discussed is APOE; the disease is Alzheimer disease.