In this subgroup, CHI3L1 expression correlated significantly with MMP9 (r = 0.788; q = 0.010; CI 0.37 to 0.94), IL1B (r = 0.705; q = 0.015; CI 0.24 to 0.91), TNF (r = 0.757; q = 0.010; CI 0.34 to 0.93), and TREM2 (r = −0.646; q = 0.025; CI -0.89 to −0.13) in MCI (Supplementary Figures 3A–E) and with IL1B (r = 0.726; q = 0.011; CI 0.30 to 0.91), LRP1 (r = 0.833; q = 0.002; CI 0.53 to 0.95), and MMP9 (r = 0.706; q = 0.022; CI 0.20 to 0.91) in AD (Supplementary Figures 3F–J). This evidence concerns the gene CHI3L1 and Alzheimer disease.