Two proteins were increased in the CSF of Aβ+ cognitively normal (CN) individuals, including SMOC2 (d = 0.19; q = 9.01 × 10− 5), which was also increased in the CSF of Aβ+ MCI patients (d = 0.29; q = 1.16 × 10− 5) and AD-dementia patients (d = 0.28; q = 1.09 × 10− 10), and YKL-40 (d = 0.13; q = 0.007), which was also increased in the CSF of AD-dementia patients (d = 0.17; q = 1.19 × 10− 5; see Fig. 1a and Table 2). This evidence concerns the gene CHI3L1 and Alzheimer disease.