As an important part of the cytoskeleton of neurons, NfL has been proven to be associated with a variety of nervous system diseases, including Alzheimer's disease (AD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and frontotemporal dementia (FTD), etc. It is conducive to predict, diagnose, monitor the progress, and evaluate the efficacy and prognosis of these diseases. This evidence concerns the gene NEFL and early-onset autosomal dominant Alzheimer disease.