GFAP and early-onset autosomal dominant Alzheimer disease: The levels of all biomarkers differed between Alzheimer’s disease patients and CU controls, with P-tau181 and GFAP levels and the Aβ42/P-tau181 ratio best differentiating the two groups [area under the curve (AUC) = 0.966, 0.932 and 0.927, respectively].