Updated AD diagnostic criteria identify core biomarkers of AD neuropathology, including amyloid-beta (A category; Aβ42/40) and phosphorylated tau variants (T category; ptau-181).8 Additionally, biomarkers of neurodegeneration or neuronal injury (N category; eg, neurofilament light chain [NfL]) and inflammation (I category; eg, glial fibrillary acidic protein [GFAP]) reflect nonspecific processes involved in AD pathophysiology. This evidence concerns the gene GFAP and Alzheimer disease.