SEMA3G and Alzheimer disease: Of these, SEMA3G emerged as a promising potential CAA specific marker, as it was detected in CAA(+) vessels from both MCI and AD, was not detected or at low levels in CAA(−) vessels (detected in one control), correlated to Aβ peptide levels (p = 0.0016; R2 = 0.69), and was not detected in the previous plaque proteomic studies.