GFAP and Alzheimer disease: The cortical percentage of GFAP burden was lowest in limbic predominant AD (median [IQR], 20% [18%-24%]) but plateaued in typical AD (median [IQR], 28% [24%-33%]; post hoc P < .001) and hippocampal sparing AD (median [IQR], 32% [23%-40%]; post hoc P < .001).