Even though elevated NfL levels are suggestive of disease activity and progression, they are still non-specific numerous neurologic diseases damage axons and thus, result in elevated levels, as NfL has potential utility in other neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis [14]. Here, NEFL is linked to early-onset autosomal dominant Alzheimer disease.