Mixed model analyses showed that levels of YKL-40 within individuals increased in both MCI and AD patients (mean (SE) 8.9 (3.0) ng/ml per year, p = 0.004 and 7.1(3.1) ng/ml per year, p = 0.02, respectively), but not in the cognitively normal group (p = 0.10), as shown in Table 2 and Fig. 2. The gene discussed is CHI3L1; the disease is Alzheimer disease.