A particularly striking finding is that GFAP measured in plasma has a better discriminative performance to distinguish between individuals with and without amyloid pathology across the Alzheimer's disease (AD) clinical continuum compared to GFAP measured in CSF (Baiardi et al., 2022; Benedet et al., 2021; Simrén et al., 2022). Here, GFAP is linked to early-onset autosomal dominant Alzheimer disease.