SLC44A4 and Alzheimer disease: All synaptic biomarkers, except Ng36, were significantly positively correlated with CSF total-tau concentrations in the FTD biomarker group (Ng22 r = 0.57; SNAP-25tot r = 0.71; SNAP-25aa40 r = 0.54; synaptotagmin-1 r = 0.68; all p < 0.0001) and AD biomarker group (Ng22 r = 0.86; SNAP-25tot r = 0.77; SNAP-25aa40 r = 0.73; synaptotagmin-1 r = 0.88; all p < 0.01).