MAPT and Alzheimer disease: These findings highlight the importanceof solution conditions in the formation of pathological amyloids,emphasized further by a recent study showing that in vitro assemblyconditions with recombinant tau can drive the formation of vastlydifferent amyloid fibril polymorphs, a small subset of which recapitulatedthe AD and chronic traumatic encephalopathy (CTE) fibril fold wheninorganic salt concentration and shaking were carefully controlled.