GFAP and early-onset autosomal dominant Alzheimer disease: Intriguingly, in other neurodegenerative diseases (e.g., Alzheimer’s disease (AD), GRN-frontotemporal dementia (GRN-FTD)), and even in older people at high risk for dementia, elevated blood GFAP levels have been reported to have some predictive value, being associated with faster cognitive decline and reduced brain volumes [22].