Presynaptic synaptosomal-associated protein 25 (SNAP-25), synaptotagmin, or growth-associated protein-43 (GAP-43) as well as post-synaptic neurogranin levels are altered in AD CSF and are reliable biomarkers of synaptic impairment, as early as in the preclinical stage of the disease [11, 12]. The gene discussed is GAP43; the disease is Alzheimer disease.