APOE and Mental deterioration: In line with these observations, APOE-status seemed to explain some of the individual variability observed in MCI individuals, carriers of the APOE e4 allele seemed not only more impaired, but also more atrophied when compared to non-carriers, suggesting that the APOE e4 allele (Corder et al., 1993, 1995; Lambert and Amouyel, 2011) could modulate the degree of phenotypic expression even in cases of mild cognitive decline (Liu et al., 2010a; Sun et al., 2012).