Some studies reported decreased hippocampal volume in young and old cognitively normal APOE4 carriers (Wishart et al., 2006; Crivello et al., 2010; O’Dwyer et al., 2012), while other did not find hippocampal atrophy (Honea et al., 2009; Haller et al., 2017). This evidence concerns the gene APOE and hippocampal atrophy.