Biomarker research in ALS has led to the identification of p75ECD from urine [15], phosphorylated neurofilament heavy (pNfH) in cerebrospinal fluid (CSF) [16], and neurofilament light (NfL) in serum [17] as diagnostic, prognostic, and pharmacodynamic biomarkers. The gene discussed is NEFL; the disease is amyotrophic lateral sclerosis.