Elevated CHI3L1 levels have been reported in various neuroinflammatory and neurodegenerative disorders, including multiple sclerosis [18], neuromyelitis optica [19], Alzheimer's disease [20], and Parkinson's disease [21], where it is closely associated with glial activation and tissue remodeling [22]. Here, CHI3L1 is linked to early-onset autosomal dominant Alzheimer disease.