In a recent study, including ALS patients (n = 234), ALS mimics (n = 44), as well as non-neurological disorder controls (n = 9), SF NFL, CSF pNFH, and plasma NFL levels were significantly increased in ALS patients, with authors concluding pNFH had diagnostic value capable of differentiating ALS from clinically relevant mimics [190]. This evidence concerns the gene NEFL and nervous system disorder.