Autosomal-dominant (AD)- PFBC is caused by mutations in the platelet-derived growth factor subunit B (PDGFB) (Keller et al., 2013) and its receptor–PDGFRB (Nicolas et al., 2013b), solute carrier family 20 member 2 (SLC20A2) (Wang et al., 2012), and xenotropic and polytropic retrovirus receptor 1 (XPR1) (Legati et al., 2015). Here, XPR1 is linked to Alzheimer disease.