Notably, this U1 proteopathy, unlike Tau, is almost exclusively present in AD and Down’s syndrome (Bai et al., 2013; Hales et al., 2014b), but not in any other types of dementia or neurodegenerative diseases that involve no amyloid and Tau tangle pathologies, providing a unique clue to the mechanism of AD. The gene discussed is MAPT; the disease is Down syndrome.