Endoscopic corpus callosotomy for drug-resistant epilepsy due to cerebral folate transporter deficiency: illustrative case.

BACKGROUND: Cerebral folate transporter deficiency (FOLR1-related CFTD, MIM #613068) is a rare, autosomal recessive neurological disease characterized by markedly deficient CSF folate levels arising from impaired transport of folate across the blood-brain barrier. Current research highlights the role of folinic acid in treatment for patients with CFTD. To date, there has been minimal published evidence on seizure management for CFTD patients whose conditions are refractory to folinic acid treatment, and there are no standardized approaches for guiding care in this subset. OBSERVATIONS: The authors report a successful clinical outcome after corpus callosotomy in a patient with drug-resistant epilepsy (DRE) secondary to folinic acid-refractory CFTD. LESSONS: This case represents the first documented surgical treatment for DRE in this patient population. Intracranial epilepsy surgery might play an important role for managing DRE in this patient population in the future. https://thejns.org/doi/10.3171/CASE25793.