In this study, we havemeasured levels of the pericyte marker, platelet-derived growth factorreceptor-β (PDGFRB), and fibrinogen (to assess blood–brain barrier leakage), andanalyzed their relationship to indicators of microvessel density (von Willebrandfactor level), ante-mortem oxygenation (myelin-associatedglycoprotein:proteolipid protein-1 ratio and vascular endothelial growth factorlevel), Aβ level and plaque load, in precuneus and underlying white matter from49 AD to 37 control brains. The gene discussed is PLP1; the disease is Alzheimer disease.