A recent meta-analysis on more than 10,000 individuals demonstrated that individuals with human immunodeficiency virus (HIV), FTD, ALS, and Huntington’s disease (HD) presented with CSF NfL concentrations averaging 21-fold, 11-fold, eightfold, and sixfold higher than CU controls, respectively31. Here, NEFL is linked to amyotrophic lateral sclerosis.