Our study aimed to: 1)investigate the diagnostic utility of CSF Aβ42, t-tau, and p-tau to differentiate normal-pressure-hydrocephalus(NPH) from Alzheimer’s-disease(AD) and normal-controls; and 2)investigate if age and ventricular size affect the levels of CSF biomarkers in NPH patients. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.