The US Food and Drug Administration (FDA) has approved the expanded use of leucovorin (Wellcovorin) for the treatment of brain folate transport deficiency associated with the FOLR1 gene variant in adult and pediatric patients.[1] This rare genetic condition affects the transport of folate (a B vitamin) into the brain and causes serious neurological complications, including developmental delays, movement disorders, seizures and other neurological problems.[1] The approval was based on a systematic review of the published literature and case reports involving 27 patients, 24 of whom showed improvement in symptoms, including reduction in seizures and improvement in motor function.[3] However, the FDA retracted earlier statements that leucovorin could help "hundreds of thousands" of children with autism, saying there was insufficient evidence for this indication.[4] Leukovorin is the first approved treatment for this rare genetic condition, which affects about one in a million Americans.[4]