The U.S. Food and Drug Administration approved leucovorin (Wellcovorin) for cerebral folate deficiency caused by pathogenic variants in the folate receptor 1 gene, but declined broader approval for autism-spectrum indications. The decision follows a review of case reports, mechanistic data and a literature package rather than new randomized trials. FDA materials and agency statements emphasize the treatment’s narrow, genetic indication and warn against extrapolating benefits to broader autistic populations. The move reverses earlier public statements by senior administration officials that suggested a wider use for autism, sparked a surge in off‑label prescribing, and prompted scrutiny from clinicians and patient advocates. The agency said it based its label expansion on specific genetic evidence for CFD-FOLR1 and found insufficient data to support leucovorin as a general autism therapy.