GFAP and amyotrophic lateral sclerosis: The reliability of this approach was confirmed by comparing SOD1‐ALS patients before treatment with matched controls, which reproduced previously described alterations of SOD1‐ALS biomarkers including the neurofilaments NfL and NfH, SOD1, Tau‐isoforms, UCHL1, GFAP, and CHIT1.16, 18, 19