As a sensitive biomarker of macrophage activation, dysregulated expression of CHIT1 in the circulation or local tissue has been reported in a variety of human diseases, including Gaucher’s disease, diabetes, sarcoidosis, inflammatory bowel disease, atherosclerosis, Alzheimer’s disease, and prostate cancer (Kanneganti et al, 2012; Elmonem et al, 2016). Here, CHIT1 is linked to Alzheimer disease.