PDGFRB and Alzheimer disease: Fibrinogen level in the white matter was significantlyhigher in AD than controls (P = 0.05) (Figure 5(b)) and remained higher afteradjustment for hemoglobin but not vWF level (Supplementary Figure 2(c) and (d)).Unlike in the precuneus, in underlying white matter, PDGFRB correlatedpositively (rather than negatively) with fibrinogen level (r = 0.36,P < 0.0001) (Figure 5(c)).