The Food and Drug Administration on Tuesday approved the generic medication leucovorin for treating cerebral folate deficiency, a rare genetic brain disorder, while distancing itself from earlier suggestions by the Trump administration that the drug could help many people with autism.

The agency approved leucovorin for children and adults with the genetic condition that limits delivery of folate, an essential form of vitamin B, to the brain. FDA officials estimate the condition affects fewer than 1 in a million people in the United States.

The approval represents a significant narrowing from statements made at a September White House news conference, where President Trump and FDA Commissioner Marty Makary announced the drug was under review to benefit autism patients. Makary suggested at the event that "20, 40, 50% of kids with autism" might benefit from the treatment. The announcement followed promises from Health Secretary Robert F. Kennedy Jr. to determine the cause of autism by September.

Senior FDA officials told reporters Monday that their review focused on the strongest available evidence, which only supported the drug's use for patients with the rare genetic mutation affecting brain folate levels. Officials also noted that one study supporting the drug's use for autism was retracted earlier this year.

Patients with cerebral folate deficiency experience movement disorders, seizures and other neurological problems that can resemble autism symptoms. However, professional medical societies remain uncertain about the drug's effectiveness for autism treatment. The American Academy of Pediatrics does not recommend routine use of leucovorin for autistic children, even those with cerebral folate deficiency, citing limited research from small-scale studies.

Prescriptions for leucovorin among children aged 5 to 17 increased 71% above normal levels in the three months following Trump's September announcement, according to research published in The Lancet. Families have reported difficulties filling prescriptions in recent weeks, prompting FDA officials to allow imports from foreign manufacturers to boost supply.