New guidelines for the diagnosis of AD in clinical research take into account: biomarkers of Aβ plaques (labeled “A”) such as low CSF Aβ42 and cortical amyloid PET ligand binding; biomarkers of fibrillar Tau (labeled “T”), such as elevated CSF p-Tau and cortical Tau PET ligand binding; biomarkers of neurodegeneration or neuronal injury (labeled “(N)”), such as elevated CSF Tau, [18F]FDG PET hypometabolism and atrophy on MRI [43]. This evidence concerns the gene MAPT and Alzheimer disease.