Several key protein biomarkers measured in plasma and serum, including Amyloid beta 42/40 ratio15, Neurofilament Light Chain (NfL)16, Glial Fibrillary Acidic Protein (GFAP), and phosphorylated tau (p-Tau 181 and 21712,17) were associated with decline in cognitive function and risk of AD/ADRD16. This evidence concerns the gene NEFL and Alzheimer disease.