GFAP and Alzheimer disease: This lack of association may reflect the temporal sequence of AD pathology, in which pTau-217 captures early amyloid accumulation before domain-specific cognitive impairments in memory emerge.30 By contrast, GFAP and NfL are general markers of neuroinflammation and axonal injury, which may reflect neuronal damage from non-AD related pathology such as cerebrovascular disease, which affects functional impairments in memory.31,32