Electroencephalographic and seizure manifestations of pyridoxal 5′-phosphate-dependent epilepsy

Abstract

We describe the electroencephalographic and clinical seizure manifestations of pyridoxal 5′-phosphate-dependent epilepsy (PLP-DE) in two patients [diagnosis confirmed by low cerebrospinal fluid (CSF) PLP, complete resolution of previously intractable seizures with PLP supplementation, negative pyridoxine-dependent epilepsy CSF biomarkers, and/or positive disease causing pyridox(am)ine 5′-phosphate oxidase gene mutation] along with a comprehensive review of the literature. One patient presented with neonatal tonic status epilepticus with subsequent generalized tonic–clonic seizures, and the second, with refractory complex partial seizures starting at 2years of age. The pretreatment EEG revealed, interictally, burst suppression, multifocal independent sharp waves, and electrical status epilepticus in sleep. Ictally and interictally, it revealed runs of unilateral spike/slow waves. Previously reported features include burst suppression, myoclonus, tonic seizures, clonic seizures, and spasms. In the appropriate clinical scenario, the aforementioned features should raise the possibility of PLP-DE and appropriate treatment should be initiated. The first late-onset case (at 2years) of PLP-DE is reported.