APOE and hippocampal atrophy: In cognitively normal adults with different genetic risk of Alzheimer's disease, based on their Aβ-amyloid levels and apolipoprotein E (APOE) ε2/ε3/ε4 genotype, Porter et al. (46) reported faster rates of cognitive decline and hippocampal atrophy in individuals with higher Aβ-amyloid levels and APOE ε4 + ve, that did not carry the rs17070145-T allele (46).