MAPT and cerebral amyloid angiopathy: Specifically, the FoldC conformation of PAM4 stabilised by the K353-D358 salt-bridge is also found in tau C-fold protofilament polymorphs linked to Alzheimer’s disease (AD), Gerstmann-Sträussler-Scheinker (GSS), primary age-related tauopathy (PART) and cerebral amyloid angiopathy (CAA), while showing reasonable fit to chronic traumatic encephalopathy (CTE) polymorphs (Fig. 5).