() The Food and Drug Administration said Monday it has initiated approval of a folate supplement for patients with a rare neurological condition that causes autism-like symptoms, marking the agency’s latest effort to address what officials call a surge in autism diagnoses.

The FDA approved leucovorin calcium tablets for cerebral folate deficiency, a condition that prevents the vitamin folate from reaching the brain. Patients typically experience developmental delays, seizures and movement problems, along with autistic behaviors including social communication difficulties and repetitive actions.

“We have witnessed a tragic fourfold increase in autism over two decades,” FDA Commissioner Dr. Marty Makary said in a statement. “Children are suffering and deserve access to potential treatments that have shown promise.”

The agency is working with pharmaceutical company GSK, which manufactures the drug under the brand name Wellcovorin, to update labeling for both adult and pediatric patients. GSK has agreed to collaborate on the relabeling process as the holder of the drug’s New Drug Application.+

This comes as President Donald Trump announced that acetaminophen, the active ingredient in Tylenol, causes autism.

Health Secretary Robert F. Kennedy Jr. first raised the idea of Tylenol use during pregnancy as a cause of autism, though doctors say the medicine is safe and not linked to the condition. Autism has been a particular focus for Kennedy, who has called the condition an “epidemic.”

What is leucovorin?

Leucovorin is typically used to treat the side effects of high-dose methotrexate, a drug used in chemotherapy and to treat autoimmune disease. It is also used to treat some types of anemia and as part of treatment regimens for certain kinds of cancer.

Leucovorin acts in the body the same way as folic acid. Folic acid aids the body in the creation of new cells, making it especially important during pregnancy. A form of B vitamins, folic acid is present in leafy greens, fruits, dried beans and peas and enriched bread products. It can also be taken as a dietary supplement.

Can leucovorin treat autism?

Limited research has shown that leucovorin can lead to language and behavior improvement in children with autism-like symptoms.

But those studies have been small, and researchers say there is not enough evidence to determine whether autistic children can benefit from leucovorin. It’s also not clear whether folate deficiency could play a role in all autism cases or just some of them.

Are there risks to leucovorin?

This would not be the first time Trump has encouraged the use of a medication that has limited or no evidence behind it.

During the COVID-19 pandemic, he promoted the use of hydroxychloroquine, an anti-malarial drug used to treat autoimmune disease, and ivermectin, an anti-parasitic drug used to fight parasitic worm infections and some skin conditions, to fight COVID. Both medications are ineffective at fighting COVID and can come with serious side effects.

Leucovorin also comes with a risk of side effects, including allergic reactions.