SNAP25 and early-onset autosomal dominant Alzheimer disease: Of note, the specificity of SNAP25 for Alzheimer’s disease is not absolute as CSF SNAP25 elevations have also been observed in frontotemporal dementia, albeit to a lesser extent.36,37,40 Creutzfeldt-Jakob’s disease patients exhibit even higher CSF SNAP25 elevations than Alzheimer’s disease patients, likely due to its fulminant nature.82,83 Plasma levels of VAMP2, on the other hand, did demonstrate associations with synaptic density in temporal and frontal brain regions as well as within a small area within the occipital cortex.