PNPO and early-infantile DEE: Overall, 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. If classified according to syndromes, the analysis of this cohort identified nine cases presenting as infantile spasms distributed in the three mutation types, and two cases were presenting as Ohtahara syndrome with ALDH7A1 and PNPO mutations, respectively.