In this contexts diagnosis of AD is based on biomarkers sensitive to amyloidosis (decreased Aβ42 in the CSF and increased retention of amyloid tracers on PET), tauopathy (increased tau and phospho-tau in CSF) and neurodegeneration (hippocampal atrophy on MRI, cortical hypo-metabolism on 18FDG-PET). The gene discussed is MAPT; the disease is Alzheimer disease.