NLGN1 and Alzheimer disease: This is the case for the synaptosomal-associated-protein 25 (SNAP25) in serum NDEs and the synaptic proteins synaptopodin, synaptophysin, GluA4-containing glutamate (AMPA4) and neuroligin 1 (NLGN1) in plasma-derived NDEs, of which the levels are decreased in AD patients compared to controls [133,138,141].