CHI3L1 and Alzheimer disease: Multiple clinical studies have demonstrated that CHI3L1 levels are elevated in individuals with inflammatory conditions like Crohn’s disease, rheumatoid arthritis, osteoarthritis, and asthma, as well as in those with neurodegenerative disorders, including AD, Parkinson’s disease, and amyotrophic lateral sclerosis (Bonneh-Barkay et al., 2010; Yu et al., 2024).