Therefore, in this cross-sectional study, we simultaneously detected the levels of classic biomarkers in the plasma of patients with AD and cognitively normal (CN) individuals from South China, including Aβ42, Aβ40, t-tau, and NfL, assessed their performance in discriminating patients with probable AD from CN participants to evaluating their ability to diagnose AD. This evidence concerns the gene NEFL and Alzheimer disease.