MAPT and Alzheimer disease: Interestingly, it was also found that in a mouse model that expressed an equal ratio of 3R and 4R human tau isoforms (6hTau mice), inoculation of different strains of tau seeds derived from different tauopathy human brains such as AD (mixed 3R and 4R tau), Pick’s disease (mostly 3R tau), progressive supranuclear palsy (mostly 4R tau) and corticobasal degeneration (mostly 4R tau) led to distinct conformation-dependent cell-type specific transmission of tauopathy without significant cross-seeding of non-corresponding tau isoforms in vivo [169].