While this may be reasonable for the amyloid+ and APOE+ groups, the wider sporadic Alzheimer’s disease is likely to show more variability in the event sequence due to the inherent disease heterogeneity, driven perhaps by genetic, e.g. the presence or absence of APOE4 (Schott et al., 2006), or lifestyle factors. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.