The current study focuses on understanding the variability in levels of plasma pTau181, pTau217, pTau231, GFAP, and NfL in relation to the clinically used biomarkers of AD (i.e., amyloid-PET, CSF pTau181, and brain atrophy on MRI) in a cohort of patients of memory clinics. The gene discussed is NEFL; the disease is Brain atrophy.