NRGN and early-onset autosomal dominant Alzheimer disease: For instance, changes in CSF levels of the presynaptic synaptosomal-associated protein of 25 kDa (SNAP25)31-33,35-37,39-42 and vesicle-associated membrane protein 2 (VAMP2) proteins31,36,38,39 have been reported in Alzheimer’s disease, frontotemporal dementia and/or Lewy body dementia compared with controls, whereas CSF-based changes in the presynaptic protein β-synuclein,41,43 the post-synaptic protein neurogranin,31,32,35-37,40-43 as well as in neuregulin-144,45 have been primarily observed in Alzheimer’s disease.