In addition to conventional clinical markers, which allow us to make a differential diagnosis and assess the possibility of concomitant diseases, the most useful biomarkers for a predictive diagnosis or diagnostic confirmation of antemortem AD are genomic markers, epigenetic biomarkers, neurotransmitters, and levels of Aβ/tau in the brain (PET Scan) and/or in body fluids [37,38,39,40,41,42,43,44,45,46]. The gene discussed is MAPT; the disease is Alzheimer disease.