Pyridoxine-dependent epilepsy is a rare, autosomal recessive, treatable cause of neonatal
seizures. Genetic testing can confirm mutations in the ALDH7A1 gene, which encodes antiquitin. To avoid delays in initiating treatment while awaiting confirmatory genetic testing, it is recommended that all neonates with unexplained
seizures should receive trial of intravenous (IV)
pyridoxine to assess for responsiveness. However, oral
pyridoxine is not commonly continued in the absence of the typical EEG changes. Two cases are presented that highlight the potential inadequacy of this single-step approach. One neonate ultimately diagnosed with
pyridoxine-dependent seizures had no EEG changes after administration of IV
pyridoxine. In contrast, another neonate who did not have this diagnosis had profound EEG changes after
pyridoxine administration. We present 2 cases that highlight the difficulties in using initial EEG response to IV
pyridoxine in establishing a diagnosis of
pyridoxine-dependent seizures in the neonate. Given the availability of
biochemical markers and gene testing, we suggest that oral
pyridoxine treatment should be continued until biochemical and/or genetic testing has confirmed the presence or absence of
pyridoxine-dependent epilepsy.