AD tau aggregates composed of all six isoforms are dominated by paired helical filaments (Goedert et al., 1992), while straight filaments are present as the major morphology of tau filaments in FTLD-tau with 4R domains, such as PSP and CBD (Flament et al., 1991; Ksiezak-Reding et al., 1994), and Pick’s disease with 3R domains (Buee and Delacourte, 1999). The gene discussed is MAPT; the disease is frontotemporal dementia.