As expected, marked increases in vascular Aβ were observed in AD patients with severe CAA when compared to control patients (Z = 3.53, p = 0.0004) and those with no CAA (Z = 3.32, p = 0.0009) or mild CAA (Z = 3.32, p = 0.0009) in the CD31+ area. The gene discussed is PECAM1; the disease is Alzheimer disease.