The inclusion of exon 10generates an isoform with four microtubule-binding domains (4R), while the absenceof this inclusion produces an isoform with three microtubule binding domains (3R).In the adult healthy brain, there is an equal proportion of 3R and 4Rforms.48,49 AGD features predominant deposition of 4R-tau, asdo progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), whereasAD is characterized by the simultaneous presence of both 3R and 4R tauproteins.44,50. Here, MAPT is linked to argyrophilic grain disease.