GFAP and Alzheimer disease: Blood‐based GFAP generally displays a similar pattern, with increases shown in AD, PDD, DLB and FTD cases compared to controls (Tang et al., 2023; Thijssen et al., 2022), and serum GFAP has been shown to distinguish between MS phenotypes (Ayrignac et al., 2020; Högel et al., 2020).