GFAP and Alzheimer disease: Furthermore, the addition of SOST to the models including only AD-related biomarkers (not including age, sex, APOE carriage) was also assessed and did not significantly increase the diagnostic potential for brain amyloid deposition in p-tau181 vs p-tau181 + SOST (AUC = 0.712 vs 0.759, P = 0.23; Fig. 2f), p-tau231 vs p-tau231 + SOST (AUC = 0.792 vs 0.816, P = 0.36, Fig. 2g) and GFAP vs GFAP + SOST (AUC = 0.762 vs 0.789, P = 0.25; Fig. 2h).