CHI3L1 and amyotrophic lateral sclerosis: The elevation of the quantity of chitinases in the context of ALS patients was first described in a proteomic study [44], specifically Chitotriosidase (CHIT1), and successive studies evaluating the diagnostic and prognostic value of CHIT1, chitinase-3-like protein-3 1 (YKL-40) and chitinase -3-like protein-2 (YKL-39) have since been published.