Since previous studies showed that MCI patients who carry an apolipoprotein E (APOE) ε4 allele are at a higher risk of progressing to AD and show higher rates of whole brain and hippocampal atrophy, any assessment of the effect of galantamine on atrophy in MCI should take into account the APOE genotype [20,21]. This evidence concerns the gene APOE and hippocampal atrophy.