Late-onset folinic acid-responsive seizures

Folinic acid-responsive seizures are rare a cause of treatable neonatal epilepsy. Patients present with multifocal, tonic or myoclonic seizures that are unresponsive to antiepileptic medication but respond to folinic acid. It has recently been shown that some patients with folinic acid-responsive seizures have an alpha-AASA deficiency due to mutations in the ALDH7A1 gene and are thus identical to pyridoxine-dependent epilepsy. We describe a 7 month old boy who presented with multifocal and tonic seizures. Prior development had been normal. EEG showed beginning hypsarrythmia that did not respond to escalating treatment with pyridoxine. After treatment with folinic acid and phenobarbital seizures stopped and the EEG improved. When folinic acid treatment was stopped after three days, seizures started again and the EEG deteriorated. Upon retreatment with folinic acid, the child became seizure free again and the EEG showed a normal pattern. Analysis of biogenic amine metabolites was not typical of folinic acid-responsive seizures and pipecolic acid and alpha-AASA in CSF was of normal range. The MRI scan showed a normal pattern without white matter loss. Genetic analysis is being performed.

This case is interesting as our patient presented not as a newborn but rather late at the age of 7 months. Also, we did not detect CSF abnormalities of pipecolic acid, alpha-AASA or biogenic amines. We therefore suggest to consider treatment with folinic acid for children with intractable seizures even beyond newborn age.