Jia et al. found that the levels of growth-associated protein 43 (GAP43), neurogranin, synaptosome-associated protein 25 (SNAP25), and synaptotagmin 1 in neuron-derived exosomes were significantly lower in the blood of AD patients, suggesting their potential use in predicting AD at pre-symptomatic stages [86]. The gene discussed is SNAP25; the disease is Alzheimer disease.