NEFL and early-onset autosomal dominant Alzheimer disease: Neurofilament light chain (NfL) levels in cerebrospinal fluid (CSF) and serum correlate with neuroaxonal damage, making them valuable for diagnosing and monitoring various neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS) [10].