PCSK1N and Alzheimer disease: Previous research in AD patients has shown that ante-mortem performed CSF-based αSyn SAAs have a particularly high sensitivity and specificity in detecting cortical rather than focal subcortical αSyn co-pathology in patients with AD post-mortem [33, 34], which is potentially relevant for a physical interaction between αSyn and tau, given the primary cortical appearance and spreading of tau in AD [35–38].