BackgroundSynaptojanin 1 is encoded by the SYNJ1(MIM 604297) and plays a major role in phosphorylation and recycling of synaptic vesicles. Mutation of SYNJ1 is associated with two distinct phenotypes; a known homozygous missense mutation (p.Arg258Gln) associated with early‐onset Parkinson disease (MIM 615530), whereas mutation with complete loss of SYNJ1 function result in a lethal neurodegenerative disease with intractable seizure and tauopathies (MIM 617389).MethodsWe report two related children from consanguineous family presented with intractable seizure, profound developmental delay, failure to thrive, acquired microcephaly, and hypotonia. The brain MRI is normal and EEG showed hypsarrhythmia.ResultThe diagnosis was achieved via whole‐genome sequencing which showed homozygous mutation in SYNJ1 (c.709C>T, p.Gln237*).ConclusionA clinical pattern of neonatal‐onset intractable seizure, profound developmental delay, muscular hypotonia, hypsarrhythmia, and no focal abnormality of brain MRI should prompt initiation of molecular genetic analysis of SYNJ1. Establishment of the diagnosis permits genetic counseling, prevents patients undergoing unhelpful diagnostic procedures and allows for accurate prognosis.

Background: Pyridoxamine 5-phosphate oxidase deficiency (PNPOD) is a rare treatable neonatal epileptic encephalopathy. It is important to raise awareness about this condition to enable early treatment. Methodology: This is a retrospective chart review of PNPOD cases followed at Mafraq Hospital during 2011-September 2017. The inclusion criteria include confirmed homozygous or compound heterozygous mutation in pyridox(am)ine-5-phosphate oxidase (PNPO) gene. Results: Seven cases were identified, all Emiratis from two tribes. Six cases from Tribe A had homozygous genetic variant C.674G>T: P. Arg255 Leu (one is presumed to have the same mutation based on confirmed proband sibling and carrier state of the parents of this sibship). One patient from Tribe B was tested abroad and has a confirmed homozygous pathogenic variant in PNPO gene (details not available). All six patients with the identical mutation are from one Emirati tribe suggest a founder effect. Two neonates treated in the first few days of life had the best clinical outcome of seizure control and neurodevelopment. One mortality (the deceased sibling of a normally developing child with this disease) highlights the great importance of early treatment. The remaining four patients had incomplete seizure control with neurobehavioral delay. Patients with intractable epilepsy and poor neurodevelopment never received pyridoxal 5-phosphate in the 1 st days of life, although they received pyridoxine and other anti-seizure medications. Conclusion: PNPOD is a treatable neonatal epileptic encephalopathy; however, early treatment is essential for optimal outcomes. A management algorithm for intractable neonatal seizures emphasizing the crucial "treat before you diagnose" approach is critical for such cases.

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