GFAP and early-onset autosomal dominant Alzheimer disease: Furthermore, we assessed whether Aβ PET or blood-based glial fibrillary acidic protein (GFAP), neurofilament light (NfL) or Aβ1-42/Aβ1-40 as well as other Alzheimer’s disease risk factors like a polygenic risk score (PRS), education or episodic memory performance at baseline could provide additional value in the prediction of asymptomatic Aβ accumulation within a median time period of 5 years.