Investigators from our group have shown that the combination of cognitive performance and medial temporal atrophy substantially improves prediction of MCI to AD progression in comparison to prediction based on individual risk factors (Heister et al., 2011), and also that the combination of APOE genotype and brain atrophy outperforms models based on either variable alone (McEvoy et al., 2009). This evidence concerns the gene APOE and Alzheimer disease.