APOE and Alzheimer disease: Genetic studies of late-onset Alzheimer’s disease (LOAD) point to a number of susceptibility genes, including several that belong to one of three classes of molecules: the apolipoprotein family (the most notable of which is apolipoprotein E [11, 59]; the low density lipoprotein receptor (LDLR) family [22, 31]; and the vacuolar protein sorting-10 (VPS10) domain containing receptor family.