APOE and early-onset autosomal dominant Alzheimer disease: Continuing the theme of genetic risk to Alzheimer’s disease, MRI measurements of CBF have identified lower grey matter CBF in young, healthy APOE-ε4 carriers, compared to non-carriers and established a negative association between CBF and genetic risk of Alzheimer’s disease, even once APOE status was removed (Chandler et al., 2019).