Moreover, evidence suggests that elevated CSF p-tau181 may not reliably reflect tau-tangle pathology as a state marker because it identifies A+/T− subtypes with significant clinical impairment and progression.39 While other p-tau epitopes have yet to be evaluated in this context, CSF p-tau217 shows a stronger association with tangle burden, as measured by in vivo tau-PET imaging,21 highlighting its potential as a more clinically relevant marker of tau-tangle pathology in AD. Here, MAPT is linked to Alzheimer disease.