Transgenic AD mouse models expressing the different APOE isoforms showed earlier accumulation of amyloid in the presence of APOE-ε4 (Kim et al., 2009), consistent with higher levels of amyloid seen in humans with APOE-ε4 (Rebeck et al., 1993; Schmechel et al., 1993; Reiman et al., 2009). This evidence concerns the gene APOE and Alzheimer disease.