GFAP had good AUCs for identification of amyloid status (total cohort: AUC = 0.79, 95%CI: 0.76–0.81; SCD and MCI set: AUC = 0.80, 95%CI: 0.76–0.85), and reasonable AUCs for discrimination of controls from FTD (AUC = 0.73, 95%CI: 0.67–0.77) or controls from DLB (AUC = 0.76, 95%CI: 0.71–0.83). Here, GFAP is linked to frontotemporal dementia.