Of these 25 studies, 12 were conducted for the different serum levels of YKL-40 between DM patients and healthy controls, 5 were analyzed for YKL-40 levels between GDM patients and healthy controls, and 8 were detected for YKL-40 levels between DM patients with different degree of albuminuria and healthy controls. The gene discussed is CHI3L1; the disease is diabetes mellitus.