MAPT and Alzheimer disease: Here we examine the onset of circadian dysfunction in an AD mouse model that expresses the human 695-amino acid isoform of the amyloid precursor protein (APP) as well as the human P301L mutation of the microtubule-associated protein tau (MAPT) gene (TAPP mice, also known as APPSwe-Tau, Taconic Model 2469)19.