GFAP and Alzheimer disease: Blood levels of neurofilament light chain (NFL), glial fibrillary acid protein (GFAP), a marker of astroglial injury, and neurogranin, are increased in blood in neurodegeneration, although these are not specific to AD (Hampel et al., 2018; Hawksworth et al., 2022; Leuzy et al., 2022).