MAPT and Alzheimer disease: It has been reported that increased p-tau T217 levels in CSF are related to the brain amyloid load–positive participants already at the preclinical stage, further supporting that this biomarker is AD-specific.6 The specificity of T217 tau phosphorylation change for AD surpasses other p-tau sites such as T181, S199, S202, and T205.6 These data suggest that p-tau T217 represents a promising AD biomarker.