The Food and Drug Administration has approved leucovorin as the first treatment for cerebral folate transport deficiency, a rare neurological disorder that affects an estimated 1 in 1 million people worldwide. The condition, which typically appears in young children, can cause developmental delays, seizures, and movement abnormalities.
Notably absent from the FDA's announcement was any mention of leucovorin as a treatment for autism — a possibility that gained public attention in September 2025 when President Donald Trump and administration officials suggested the agency had begun a process to approve the drug for managing symptoms in autistic individuals. No timetable or formal process for such an approval has materialized.
Leucovorin is a prescription medication traditionally used to counteract the toxic side effects of chemotherapy drugs like methotrexate. It works by helping restore folic acid to healthy cells. For cerebral folate deficiency, the drug addresses the underlying problem of impaired folate transport to the brain. Experts have noted that early intervention is critical. "Case reports support complete clinical and radiological recovery when treatment is provided before the age of 2 years," said Antonio Hardan, MD, a professor of psychiatry and behavioral sciences at Stanford University.
While some research has suggested an overlap between cerebral folate deficiency and autism — with estimates that 38–70% of autistic children may have the folate condition — experts caution that those figures may be inflated due to unreliable testing methods. Having cerebral folate deficiency may increase the risk of autism, but the reverse does not necessarily hold. Alycia Halladay, chief science officer for the Autism Science Foundation, welcomed the approval for cerebral folate deficiency patients while emphasizing that more research is needed before leucovorin could be considered an autism treatment.