We found treatment with the DYRK1A inhibitor PST-001 (Stensen et al., 2021a), caused an in vivo reduction of phosphorylation of panneuronally expressed human Tau at S262, a site previously identified as being phosphorylated by DYRK1A leading to AD pathology (Azorsa et al., 2010; Frost et al., 2011; Tenreiro et al., 2014). This evidence concerns the gene MAPT and Alzheimer disease.