SNAP25 and early-onset autosomal dominant Alzheimer disease: p-tau/Aβ42 ratio was preferentially selected as a specific marker for Alzheimer’s disease instead of individual markers, as it has been shown to be superior in assessing β-amyloid pathology.32 SNAP-25 was the only synaptic marker that differed between the clinical groups in our material and it has been shown to possess the best discriminatory power to distinguish Alzheimer’s disease from non-Alzheimer patients compared with other synaptic biomarkers28; therefore, we selected it as a synaptic dysfunction outcome measure.