Consistent with this notion, we found that samples from two of the youngest individuals with DS in our study (19 and 25 y old) exhibited robust levels of Aβ prions but insignificant levels of tau prions; in adjacent formalin-fixed sections, we found that these donors had low levels of plaques and tangles (SI Appendix, Fig. S2). The gene discussed is MAPT; the disease is Dravet syndrome.