In our 69-person cohort, the seizure presentation of 11 patients was consistent with ES, including four patients with mutations in the ALDH7A1, six with mutations in the PNPO, and one with mutation in the PLPBP. By analyzing the presentation among them, we revealed that ES might be a common form of seizures in PNPO deficiency, and EEG presented as hypsarrhythmia or burst suppression pattern. Here, PNPO is linked to Hypsarrhythmia.