Given the established staging framework, AD biomarker levels, including plasma phosphorylated‐tau 217 (p‐tau217), which reflects amyloid and tau (AT) pathology, as well as non‐specific AD‐related biomarkers such as glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL), are expected to vary across different tau stages.18, 19, 20. This evidence concerns the gene GFAP and Alzheimer disease.