Trump Administration updates on leucovorin for autism don't stack up

Embargoed until: Publicly released: 2026-01-22 12:00

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Last September, the US government said it would update advice to allow the use of leucovorin for cerebral folate deficiency, which they said has been linked with autism. However, in a 'Perspective' article, US doctors say this is misguided because there's no evidence that cerebral folate deficiency (CFD) plays a role in autism. They also point out that the approval statement issued for leucovorin didn’t actually apply to autism - only to a rare hereditary disorder, FOLR1-related cerebral folate transport deficiency (FOLR1-CFTD). The government statements appear to have been based on previous studies that detected antibodies to the FOLR1 protein in autistic people, the authors say, but these found levels were within the normal range. Following the government update, leucovorin will probably be used off-label for autism more frequently, they add, which is a worry because doses used for autism can be very high, the side effects and efficacy of the drug are uncertain, and there's already a leucovorin shortage in the USA.