Since NfL is a product of brain injury (i.e., NfL disintegrates from the axon upon damage) and GFAP is a responder to both brain injury as well as amyloid and tau aggregates, we hypothesize that GFAP serves as a more sensitive marker for Alzheimer’s disease pathological processes. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.