MAPT and Alzheimer disease: Oligomers have been specifically associated with Alzheimer disease, Parkinson disease, and frontotemporal dementia, and it has been proposed that the disease pathology could be caused solely by soluble toxic entities of Aβ, α-synuclein or tau, respectively (Lesne et al., 2006; Berger et al., 2007; Shankar et al., 2008).