Pyridoxine responsive epilepsy caused by a novel homozygous PNPO mutation

B Jaeger; N G Abeling; G S Salomons; E A Struys; M Simas-Mendes; V G Geukers; B T Poll-The

doi:10.1016/j.ymgmr.2016.01.004

Pyridoxine responsive epilepsy caused by a novel homozygous PNPO mutation

Mol Genet Metab Rep. 2016 Feb 10:6:60-3. doi: 10.1016/j.ymgmr.2016.01.004. eCollection 2016 Mar.

Authors

B Jaeger¹, N G Abeling², G S Salomons³, E A Struys³, M Simas-Mendes³, V G Geukers⁴, B T Poll-The¹

Affiliations

¹ Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands.
² Laboratory of Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands.
³ Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands.
⁴ Pediatric Intensive Care Department, Academic Medical Center, Amsterdam, The Netherlands.

Abstract

We report a patient with anti-epileptic treatment refractory neonatal seizures responsive to pyridoxine. Biochemical analysis revealed normal markers for antiquitin deficiency and also mutation analysis of the ALDH7A1 (Antiquitin) gene was negative. Mutation analysis of the PNPO gene revealed a novel, homozygous, presumed pathogenic mutation (c.481C > T; p.(Arg161Cys)). Measurements of B6 vitamers in a CSF sample after pyridoxine administration revealed elevated pyridoxamine as the only metabolic marker for PNPO deficiency. With pyridoxine monotherapy the patient is seizure free and neurodevelopmental outcome at the age of 14 months is normal.

Keywords: Antiquitin; CSF, cerebrospinal fluid; Epilepsy; Neonatal; PDE, (classic) pyridoxine dependent epilepsy; PLP, pyridoxal-5′-phosphate; PLP-DE, pyridoxal-phosphate dependent epilepsy; PNPO; PNPO, pyridox(am)ine-5′-phosphate oxidase; Pyridoxal-phosphate; Pyridoxine; α-AASA, alpha-aminoadipic semialdehyde dehydrogenase.