In this explorative cohort, we measured the synaptic proteins SNAP25, VAMP2, Ng, NPTX2, and GluR4 in clinical CSF samples of patients with AD, FTD, and SCD and studied their correlation with classical fluid biomarkers Aβ42, Tau, PTau, and NfL. Here, GRIA4 is linked to Schnyder corneal dystrophy.