Pyridoxine-dependent epilepsy: an under-recognised cause of intractable seizures.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive disorder causing intractable seizures in neonates and infants. PDE patients are typically resistant to anti-epileptic treatment but respond to the administration of pyridoxine. Different seizure types have been reported in PDE, and episodes of status epilepticus are common. Electroencephalographic or neuroimaging abnormalities are not pathognomonic for this disorder. Intellectual disability is frequent at the follow-up. Recently, elevated urinary α-aminoadipic semialdehyde has been shown to be a reliable biomarker of this disorder, and mutations in the ALDH7A1 gene, encoding α-aminoadipic semialdehyde dehydrogenase, have been demonstrated in the large majority of PDE patients. However, early consideration of a pyridoxine trial remains the most important issue in a neonate or in an infant with intractable early onset seizures.