For example, in one study, NfL in the CSF among recruited confirmed healthy adults (n = 27, median age = 33 years, range = 26–43 years of age), ranged from 1000 to 8532 pg/ml, which is lower than our observed mean NfL levels for the ALS (13,326 pg/ml) group [28]. The gene discussed is NEFL; the disease is amyotrophic lateral sclerosis.