The main aim of this study is to examine the specific relationships between plasma pTau181, pTau217, pTau231, GFAP, and NfL in comparison to biomarkers used in clinical practice for detecting AD-related pathologies (i.e., amyloid PET, CSF pTau181, and atrophy on MRI) in a cohort of patients of tertiary memory clinics. The gene discussed is GFAP; the disease is Atrophy.