The FDA approved leucovorin (Wellcovorin) for cerebral folate deficiency due to confirmed FOLR1 variants but rejected broader claims linking the drug to autism treatment. Agency notices and reporting made clear the approval was based on case literature and mechanistic data for the specific genetic syndrome rather than randomized trials supporting autism use. The decision followed public and political interest that had pushed prescriptions upward; regulators limited the label to the rare genetic condition and cautioned against off‑label use for autism. The episode illustrates regulatory caution in respecifying old drugs for ultra‑rare genetic indications and the tension between public advocacy, politics, and evidence thresholds for broader indications.