When AD patients with varying CAA severity were grouped, CD31 fluorescence colocalization with HS was not significantly different between the no CAA and mild CAA subgroups (H(2) = 4.53, p = 0.1038, mean AD no CAA = 0.51, mean AD mild CAA = 0.48, mean AD severe CAA = 0.55) but significantly increased in the severe CAA group (Z = 2.06, p = 0.0392) (Figure 2E). The gene discussed is PECAM1; the disease is Alzheimer disease.