GFAP and early-onset autosomal dominant Alzheimer disease: Previous studies have shown that plasma GFAP levels are associated with Alzheimer's disease pathology measured in CSF12,21,26,27 and plasma21,26,28 and by neuroimaging.12,29 More specifically, GFAP has been suggested to play a role in the association between amyloid pathology and early deposition of neurofibrillary tau tangles.26 Moreover, GFAP has been shown to predict conversion from mild cognitive impairment to Alzheimer's disease dementia.27