They revealed that the presynaptic (synaptosomal-associated protein 25 (SNAP25), growth associated protein 43 (GAP43)) and postsynaptic markers (Ng) are elevated in CSF in early Alzheimer’s disease, i.e., in Aβ-positive individuals without evidence of tau pathology. This evidence concerns the gene GAP43 and early-onset autosomal dominant Alzheimer disease.