MAPT and Alzheimer disease: DYRK1A-dependent MAPT/Tau phosphorylation is one of the molecular bases for the early onset of Alzheimer disease in most Down syndrome patients (Ryoo et al, 2007), and DYRK1A inhibition is believed to be effective for treatment of Alzheimer disease (Stotani et al, 2016; Branca et al, 2017).