MAPT and Alzheimer disease: While robust p-Tau (Ser202/Thr205) expression is observed in 7- to 8-month-old 5xFAD mice (late-stage AD), it is possible that 3.5-month-old 5xFAD mice (early-stage AD) are not suitable for assessing the effect of DYRK1A knockdown on tau hyperphosphorylation (62, 63).