Furthermore, the difficulty in identifying Alzheimer’s disease in iNPH patients, notably due to misleading CSF biomarkers in iNPH (Aβ42, T-Tau and P-Tau are usually low due to abnormalities in protein drainage into the CSF),27 could have led us to underestimate the prevalence of iNPH among our Alzheimer’s disease patients. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.