CHI3L1 and amyotrophic lateral sclerosis: All differentially abundant proteins in ALS versus healthy controls were proteins that were increased in ALS and included CHIT1 and CHI3L1, along with UCHL1 and Alpha 1‐antichymotrypsin (SERPINA3) which have recently been independently identified as significantly higher in ALS patients (Oeckl et al., 2020; Oh et al., 2023).