APOE and early-onset autosomal dominant Alzheimer disease: Baseline ADAS-Cog13 (The Alzheimer's Disease Assessment Scale) score was associated with CSF ferritin (P=0.006; Table 2), ApoE levels (P=0.0003) and tau/Aβ1–42 ratio (P=0.025), independently, in a multiple regression model containing the AD biomarkers and other clinical variables.