PECAM1 and Alzheimer disease: Regarding the 670 AD female brains, the results show that the CHID1 expression levels correlated with IBA1 (r = 0.2172, p < 0.0001), CD31 (r = −0.09, p = 0.0098), CALB1 (r= 0.1474, p = 0.0001), and NRGN (r = 0.1414, p = 0.0002) (Figure 5C).