The synaptic markers NG and SNAP-25 were elevated in AD compared to both SCD and MCI participants (p < 0.001 for both markers), in AD versus SCD (p < 0.001 for both), and in AD versus MCI subjects (p < 0.0001 for NG and p < 0.001 for SNAP-25). Here, SNAP25 is linked to Alzheimer disease.