FDA Approves Leucovorin for Rare Brain Disorder, Not Autism Treatment

The U.S. Food and Drug Administration (FDA) has approved leucovorin for the treatment of cerebral folate deficiency, a rare neurological disorder characterized by low levels of vitamin B9 in the brain. The approval, announced on March 10, does not include the use of leucovorin as a treatment for autism.

Despite claims from the Trump administration in September 2025 that the FDA was considering leucovorin for autism, no formal approval process or timeline has been established for this purpose.

Leucovorin’s Approval for Cerebral Folate Deficiency

Leucovorin, a prescription medication primarily used to reduce the toxic side effects of chemotherapy agents like methotrexate, has been approved as the first treatment for cerebral folate deficiency. The FDA’s decision is seen as a significant milestone for patients with the condition.

“Today’s approval represents a significant milestone for patients living with cerebral folate transport deficiency due to the FOLR1 variant, a rare genetic condition that has had no FDA-approved treatment options until today.”
— Marty Makary, MD, FDA Commissioner

Understanding Cerebral Folate Deficiency

Cerebral folate deficiency typically manifests in young children and can cause:

• Developmental delays
• Seizures
• Movement abnormalities

While the condition affects an estimated 1 in 1 million people worldwide, its true prevalence remains unknown. Some studies suggest that 38–70% of autistic children may have cerebral folate deficiency, though experts caution that these estimates may be inflated due to reliance on FRAT tests, a blood exam that can be inaccurate.

It’s important to note that while individuals with cerebral folate deficiency may have a higher risk of autism, autistic people do not necessarily have a higher risk of the deficiency.

Expert Reactions to the FDA Approval

Alycia Halladay, MD, chief science officer for the Autism Science Foundation, expressed optimism about the approval for cerebral folate deficiency:

“This will probably help them. The mechanism is there. I feel any relief would be helpful.”

Antonio Hardan, MD, a professor of psychiatry and behavioral sciences at Stanford University, also commented on the significance of the approval:

“This is a long-overdue relief for individuals with cerebral folate deficiency.”