The U.S. FDA approved leucovorin (Wellcovorin) for a specific genetic form of cerebral folate deficiency (CFD‑FOLR1) but declined to broaden the label to autism spectrum disorder. Regulators based the approval on case reports and mechanistic literature rather than randomized trials, and explicitly limited the indication to patients with a confirmed FOLR1 variant. The decision follows months of high‑profile political attention that prompted a surge in off‑label prescriptions. FDA officials and outside clinicians warned that evidence for autism is weak, and experts have flagged increased off‑label use and supply strain as immediate consequences of the publicity surrounding the issue.