CHIT1 and Alzheimer disease: Each ND cohort showed higher CHIT1 levels than controls (prion disease vs. controls p < 0.001, FTD vs. controls p = 0.010, AD vs. controls p = 0.047) (Table 2, Fig. 1a), although the concentration of the marker did not significantly differ between patients with prion disease, AD, and FTD, findings that were also confirmed after age and sex adjustment (Additional file 1: Table S3).