Compared with CU individuals, patients on the AD continuum had higher GFAP and YKL-40 levels (GFAP effect size 1.15, 95% CI 0.94–1.36, p < 0.0001; YKL-40 effect size 0.38, 95% CI 0.28–0.49, p < 0.0001). This evidence concerns the gene CHI3L1 and Alzheimer disease.