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Delgadillo-Silva LF, Tasöz E, Singh SP, Chawla P, Georgiadou E, Gompf A, Rutter GA, Ninov N. Optogenetic β cell interrogation in vivo reveals a functional hierarchy directing the Ca 2+ response to glucose supported by vitamin B6. SCIENCE ADVANCES 2024; 10:eado4513. [PMID: 38924394 PMCID: PMC11204215 DOI: 10.1126/sciadv.ado4513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/20/2024] [Indexed: 06/28/2024]
Abstract
Coordination of cellular activity through Ca2+ enables β cells to secrete precise quantities of insulin. To explore how the Ca2+ response is orchestrated in space and time, we implement optogenetic systems to probe the role of individual β cells in the glucose response. By targeted β cell activation/inactivation in zebrafish, we reveal a hierarchy of cells, each with a different level of influence over islet-wide Ca2+ dynamics. First-responder β cells lie at the top of the hierarchy, essential for initiating the first-phase Ca2+ response. Silencing first responders impairs the Ca2+ response to glucose. Conversely, selective activation of first responders demonstrates their increased capability to raise pan-islet Ca2+ levels compared to followers. By photolabeling and transcriptionally profiling β cells that differ in their thresholds to a glucose-stimulated Ca2+ response, we highlight vitamin B6 production as a signature pathway of first responders. We further define an evolutionarily conserved requirement for vitamin B6 in enabling the Ca2+ response to glucose in mammalian systems.
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Affiliation(s)
- Luis Fernando Delgadillo-Silva
- Centre for Regenerative Therapies TU Dresden, Dresden 01307, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus of TU Dresden, German Center for Diabetes Research (DZD e.V.), Dresden 01307, Germany
- Cardiometabolic Axis, CR-CHUM, and University of Montreal, Montreal, QC, Canada; 1IRIBHM, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Emirhan Tasöz
- Centre for Regenerative Therapies TU Dresden, Dresden 01307, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus of TU Dresden, German Center for Diabetes Research (DZD e.V.), Dresden 01307, Germany
| | | | - Prateek Chawla
- Centre for Regenerative Therapies TU Dresden, Dresden 01307, Germany
| | - Eleni Georgiadou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London W12 ONN, UK
| | - Anne Gompf
- Centre for Regenerative Therapies TU Dresden, Dresden 01307, Germany
| | - Guy A. Rutter
- Cardiometabolic Axis, CR-CHUM, and University of Montreal, Montreal, QC, Canada; 1IRIBHM, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London W12 ONN, UK
- Lee Kong Chian School of Medicine, Nanyang Technological College, Singapore, Singapore
| | - Nikolay Ninov
- Centre for Regenerative Therapies TU Dresden, Dresden 01307, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus of TU Dresden, German Center for Diabetes Research (DZD e.V.), Dresden 01307, Germany
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Lin L, Zhang Y, Pan H, Wang J, Qi Y, Ma Y. Inconsistencies between prenatal diagnostic and genetic testing laboratories on variant validation of rare monogenic diseases. Prenat Diagn 2024. [PMID: 38898598 DOI: 10.1002/pd.6628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 05/14/2024] [Accepted: 06/10/2024] [Indexed: 06/21/2024]
Abstract
BACKGROUND The advent of next-generation sequencing (NGS) has enhanced the diagnostic efficacy for monogenic diseases, while presenting challenges in achieving consistent diagnoses. METHOD We retrospectively analyzed the concordance rate and reasons for the inconsistency between the original diagnostic result from the genetic testing laboratory and the variant validation result from the prenatal diagnostic center. The validation procedure comprised three stages: validation of variant detection, reevaluation of variant classification, and assessment of recurrence risk, which involved verifying the mode of inheritance and parental carriage. RESULT In total, 17 (6%) of the 286 families affected by rare monogenic diseases showed different results during the variant validation procedure. These cases comprised four (23.5%) with variant detection errors, 12 (70.5%) with inconsistent interpretation, and one (6%) with non-Mendelian inheritance patterns. False-positive NGS results confirmed by Sanger sequencing were related to pseudogenes and GC-rich regions. The classification of the 17 variants was altered in the 12 cases owing to various factors. The case with an atypical inheritance pattern was originally considered autosomal recessive inheritance, but was diagnosed as maternal uniparental disomy after additional genetic analysis. CONCLUSION We underscored the significance of variant validation by prenatal diagnostic centers. Families affected by monogenic diseases with reproductive plans should be referred to prenatal genetic centers as early as possible to avoid different results that may postpone subsequent prenatal diagnosis.
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Affiliation(s)
- Liling Lin
- Department of Central Laboratory, Peking University First Hospital, Beijing, China
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, China
| | - Ying Zhang
- Department of Central Laboratory, Peking University First Hospital, Beijing, China
| | - Hong Pan
- Department of Central Laboratory, Peking University First Hospital, Beijing, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yu Qi
- Department of Central Laboratory, Peking University First Hospital, Beijing, China
| | - Yinan Ma
- Department of Central Laboratory, Peking University First Hospital, Beijing, China
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3
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Thöny B, Ng J, Kurian MA, Mills P, Martinez A. Mouse models for inherited monoamine neurotransmitter disorders. J Inherit Metab Dis 2024; 47:533-550. [PMID: 38168036 DOI: 10.1002/jimd.12710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/07/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
Several mouse models have been developed to study human defects of primary and secondary inherited monoamine neurotransmitter disorders (iMND). As the field continues to expand, current defects in corresponding mouse models include enzymes and a molecular co-chaperone involved in monoamine synthesis and metabolism (PAH, TH, PITX3, AADC, DBH, MAOA, DNAJC6), tetrahydrobiopterin (BH4) cofactor synthesis and recycling (adGTPCH1/DRD, arGTPCH1, PTPS, SR, DHPR), and vitamin B6 cofactor deficiency (ALDH7A1), as well as defective monoamine neurotransmitter packaging (VMAT1, VMAT2) and reuptake (DAT). No mouse models are available for human DNAJC12 co-chaperone and PNPO-B6 deficiencies, disorders associated with recessive variants that result in decreased stability and function of the aromatic amino acid hydroxylases and decreased neurotransmitter synthesis, respectively. More than one mutant mouse is available for some of these defects, which is invaluable as different variant-specific (knock-in) models may provide more insights into underlying mechanisms of disorders, while complete gene inactivation (knock-out) models often have limitations in terms of recapitulating complex human diseases. While these mouse models have common phenotypic traits also observed in patients, reflecting the defective homeostasis of the monoamine neurotransmitter pathways, they also present with disease-specific manifestations with toxic accumulation or deficiency of specific metabolites related to the specific gene affected. This review provides an overview of the currently available models and may give directions toward selecting existing models or generating new ones to investigate novel pathogenic mechanisms and precision therapies.
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Affiliation(s)
- Beat Thöny
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zürich, Switzerland
| | - Joanne Ng
- Genetic Therapy Accelerator Centre, University College London, Queen Square Institute of Neurology, London, UK
| | - Manju A Kurian
- Zayed Centre for Research into Rare Disease in Children, GOS Institute of Child Health, University College London, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Philippa Mills
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Aurora Martinez
- Department of Biomedicine and Center for Translational Research in Parkinson's Disease, University of Bergen, Bergen, Norway
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
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Wang J, Xu X, Wei W, Song W, Wen J, Hu G, Li X, Gao C, Chen X, Liu L, Wu J. Rational Design of Salmonella typhi Acid Phosphatase for Efficient Production of Pyridoxal 5'-Phosphate. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 38602702 DOI: 10.1021/acs.jafc.4c00596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Pyridoxal 5'-phosphate (PLP) is highly valuable in food and medicine. However, achieving the efficient biosynthesis of PLP remains challenging. Here, a salvage pathway using acid phosphatase from Salmonella typhi (StAPase) and pyridoxine oxidase from Escherichia coli (EcPNPO) as pathway enzymes was established for the first time to synthesize PLP from pyridoxine (PN) and pyrophosphate (PPi). StAPase was identified as a rate-limiting enzyme. Two protein modification strategies were developed based on the PN phosphorylation mechanism: (1) improving the binding of PN into StAPase and (2) enhancing the hydrophobicity of StAPase's substrate binding pocket. The kcat/Km of optimal mutant M7 was 4.9 times higher than that of the wild type. The detailed mechanism of performance improvement was analyzed. Under the catalysis of M7 and EcPNPO, a PLP high-yielding strain of 14.5 ± 0.55 g/L was engineered with a productivity of 1.0 ± 0.02 g/(L h) (the highest to date). The study suggests a promising method for industrial-scale PLP production.
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Affiliation(s)
- Jing Wang
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xin Xu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Wanqing Wei
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Wei Song
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Jian Wen
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Guipeng Hu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
| | - Xiaomin Li
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Jing Wu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China
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5
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Chi W, Kiskinis E. Integrative analysis of epilepsy-associated genes reveals expression-phenotype correlations. Sci Rep 2024; 14:3587. [PMID: 38351047 PMCID: PMC10864290 DOI: 10.1038/s41598-024-53494-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 02/01/2024] [Indexed: 02/16/2024] Open
Abstract
Epilepsy is a highly prevalent neurological disorder characterized by recurrent seizures. Patients exhibit broad genetic, molecular, and clinical diversity involving mild to severe comorbidities. The factors that contribute to this phenotypic diversity remain unclear. Here we used publicly available datasets to systematically interrogate the expression pattern of 230 epilepsy-associated genes across human tissues, developmental stages, and central nervous system (CNS) cellular subtypes. We grouped genes based on their curated phenotypes into 3 broad classes: core epilepsy genes (CEG), where seizures are the dominant phenotype, developmental and epileptic encephalopathy genes (DEEG) that are associated with developmental and epileptic encephalopathy, and seizure-related genes (SRG), which are characterized by the presence of seizures and gross brain malformations. We find that compared to the other two groups of genes, DEEGs are highly expressed within the adult CNS, exhibit the highest and most dynamic expression in various brain regions across development, and are significantly enriched in GABAergic neurons. Our analysis provides an overview of the expression pattern of epilepsy-associated genes with spatiotemporal resolution and establishes a broad expression-phenotype correlation in epilepsy.
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Affiliation(s)
- Wanhao Chi
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
- Simpson Querrey Institute, Northwestern University, Chicago, IL, 60611, USA.
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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Latzer IT, Pearl PL. Treatable inherited metabolic epilepsies. Epilepsy Behav 2024; 151:109621. [PMID: 38237465 DOI: 10.1016/j.yebeh.2024.109621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 12/30/2023] [Accepted: 01/02/2024] [Indexed: 02/09/2024]
Abstract
Inherited metabolic epilepsies (IMEs) represent inherited metabolic disorders predominately presenting with seizures. While most IMEs are currently managed with symptomatic and supportive therapies, some are amenable to disorder-specific targeted treatments. In most cases, these treatments are effective only if given in a narrow time window early in the lives of affected patients. Hence, prompt recognition of treatable inherited metabolic epilepsies at an early age and as soon as symptoms appear has paramount importance. Herein, we provide an overview of inherited metabolic epilepsies, which presently have established targeted treatments showing clinical efficacy in reducing seizure burden and improving neurodevelopmental outcomes. These therapeutic modalities range from specific diets, vitamins, and supplementation of organic compounds to synthetic pharmacological agents and novel genetic-based therapies that alter the biochemical pathways of these disorders at the cellular or molecular level, steering them to their normal function.
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Affiliation(s)
- Itay Tokatly Latzer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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7
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Dominguez SL, Laufer BI, Ghosh AS, Li Q, Ruggeri G, Emani MR, Phu L, Friedman BA, Sandoval W, Rose CM, Ngu H, Foreman O, Reichelt M, Juste Y, Lalehzadeh G, Hansen D, Nymark H, Mellal D, Gylling H, Kiełpiński ŁJ, Chih B, Bingol B, Hoogenraad CC, Meilandt WJ, Easton A. TMEM106B reduction does not rescue GRN deficiency in iPSC-derived human microglia and mouse models. iScience 2023; 26:108362. [PMID: 37965143 PMCID: PMC10641752 DOI: 10.1016/j.isci.2023.108362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 08/28/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023] Open
Abstract
Heterozygous mutations in the granulin (GRN) gene are a leading cause of frontotemporal lobar degeneration with TDP-43 aggregates (FTLD-TDP). Polymorphisms in TMEM106B have been associated with disease risk in GRN mutation carriers and protective TMEM106B variants associated with reduced levels of TMEM106B, suggesting that lowering TMEM106B might be therapeutic in the context of FTLD. Here, we tested the impact of full deletion and partial reduction of TMEM106B in mouse and iPSC-derived human cell models of GRN deficiency. TMEM106B deletion did not reverse transcriptomic or proteomic profiles in GRN-deficient microglia, with a few exceptions in immune signaling markers. Neither homozygous nor heterozygous Tmem106b deletion normalized disease-associated phenotypes in Grn -/-mice. Furthermore, Tmem106b reduction by antisense oligonucleotide (ASO) was poorly tolerated in Grn -/-mice. These data provide novel insight into TMEM106B and GRN function in microglia cells but do not support lowering TMEM106B levels as a viable therapeutic strategy for treating FTD-GRN.
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Affiliation(s)
- Sara L. Dominguez
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
| | - Benjamin I. Laufer
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
- Department of OMNI Bioinformatics, Genentech, South San Francisco, CA 94080, USA
| | | | - Qingling Li
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Gaia Ruggeri
- Department of Biochemistry and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA
| | - Maheswara Reddy Emani
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
- Department of Biochemistry and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA
| | - Lilian Phu
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Brad A. Friedman
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
- Department of OMNI Bioinformatics, Genentech, South San Francisco, CA 94080, USA
| | - Wendy Sandoval
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Christopher M. Rose
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Hai Ngu
- Department of Pathology, Genentech, South San Francisco, CA 94080, USA
| | - Oded Foreman
- Department of Pathology, Genentech, South San Francisco, CA 94080, USA
| | - Mike Reichelt
- Department of Pathology, Genentech, South San Francisco, CA 94080, USA
| | - Yves Juste
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
| | - Guita Lalehzadeh
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
| | - Dennis Hansen
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, 2970 Hørsholm, DK, Denmark
| | - Helle Nymark
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, 2970 Hørsholm, DK, Denmark
| | - Denia Mellal
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, 2970 Hørsholm, DK, Denmark
| | - Helene Gylling
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, 2970 Hørsholm, DK, Denmark
| | - Łukasz J. Kiełpiński
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Copenhagen, 2970 Hørsholm, DK, Denmark
| | - Ben Chih
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
- Department of Biochemistry and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA
| | - Baris Bingol
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
| | | | | | - Amy Easton
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
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Pearl PL. Comment: Amenable Treatable Severe Pediatric Epilepsies. Semin Pediatr Neurol 2023; 47:101073. [PMID: 37919041 DOI: 10.1016/j.spen.2023.101073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 11/04/2023]
Abstract
AMENABLE TREATABLE SEVERE PEDIATRIC EPILEPSIES Phillip L. Pearl Seminars in Pediatric Neurology Volume 23, Issue 2, May 2016, Pages 158-166 Vitamin-dependent epilepsies and multiple metabolic epilepsies are amenable to treatment that markedly improves the disease course. Knowledge of these amenably treatable severe pediatric epilepsies allows for early identification, testing, and treatment. These disorders present with various phenotypes, including early onset epileptic encephalopathy (refractory neonatal seizures, early myoclonic encephalopathy, and early infantile epileptic encephalop athy), infantile spasms, or mixed generalized seizure types in infancy, childhood, or even adolescence and adulthood. The disorders are presented as vitamin responsive epilepsies such as pyridoxine, pyridoxal-5-phosphate, folinic acid, and biotin; transportopathies like GLUT-1, cerebral folate deficiency, and biotin thiamine responsive disorder; amino and organic acidopathies including serine synthesis defects, creatine synthesis disorders, molybdenum cofactor deficiency, and cobalamin deficiencies; mitochondrial disorders; urea cycle disorders; neurotransmitter defects; and disorders of glucose homeostasis. In each case, targeted intervention directed toward the underlying metabolic pathophysiology affords for the opportunity to significantly effect the outcome and prognosis of an otherwise severe pediatric epilepsy.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA.
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Plecko B. On pathways and blind alleys-The importance of biomarkers in vitamin B 6 -dependent epilepsies. J Inherit Metab Dis 2023; 46:839-847. [PMID: 37428623 DOI: 10.1002/jimd.12655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Over the past two decades, the field of vitamin B6 -dependent epilepsies has evolved by the recognition of a growing number of gene defects (ALDH7A1, PNPO, ALPL, ALDH4A1, PLPBP as well as defects of the glycosylphosphatidylinositol anchor proteins) that all lead to reduced availability of pyridoxal 5'-phosphate, an important cofactor in neurotransmitter and amino acid metabolism. In addition, positive pyridoxine response has been observed in other monogenic defects such as MOCS2 deficiency or KCNQ2 and there may be more defects to be discovered. Most entities lead to neonatal onset pharmaco-resistant myoclonic seizures or even status epilepticus and pose an emergency to the treating physician. Research has unraveled specific biomarkers for several of these entities (PNPO deficiency, ALDH7A1 deficiency, ALDH4A1 deficiency, ALPL deficiency causing congenital hypophosphatasia and glycosylphosphatidylinositol anchoring defects with hyperphosphatasia), that can be detected in plasma or urine, while there is no biomarker to test for PLPHP deficiency. Secondary elevation of glycine or lactate was recognized as diagnostic pitfall. An algorithm for a standardized trial with vitamin B6 should be in place in every newborn unit in order not to miss these well-treatable inborn errors of metabolism. The Komrower lecture of 2022 provided me with the opportunity to tell the story about the conundrums of research into vitamin B6 -dependent epilepsies that kept some surprises and many novel insights into pathomechanisms of vitamin metabolism. Every single step had benefits for the patients and families that we care for and advocates for a close collaboration of clinician scientists with basic research.
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Affiliation(s)
- Barbara Plecko
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
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Banerjee P, Chandra A, Mohammad T, Singh N, Hassan MI, Qamar I. Identification of high-affinity pyridoxal kinase inhibitors targeting cancer therapy: an integrated docking and molecular dynamics simulation approach. J Biomol Struct Dyn 2023:1-18. [PMID: 37578056 DOI: 10.1080/07391102.2023.2246580] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/05/2023] [Indexed: 08/15/2023]
Abstract
Pyridoxal kinase (PDXK) is a vitamin B6-dependent transferase enzyme encoded by the PDXK gene, crucial for leukemic cell proliferation. Disruption of its activity causes altered metabolism and reduced levels of nucleotides and polyamines. PDXK and pyridoxal 5'-phosphate (PLP) are overexpressed in various carcinomas, making them promising targets for drug design against cancer. Targeting PDXK may hold promise as a therapeutic approach for cancer treatment. This study focused on discovering potential inhibitors that could selectively interrupt the binding of pyridoxal phosphate (PLP) to pyridoxal kinase (PDXK). A commercially available library of 7,28,747 natural and druglike compounds was virtually screened using a molecular docking approach to target the substrate binding pocket of PDXK. Six promising inhibitors were identified, and all-atom molecular dynamics simulations were conducted on the PDXK-ligand complexes for 100 ns to assess their binding conformational stability. The simulation results indicated that the binding of ZINC095099376, ZINC01612996, ZINC049841390, ZINC095098959, ZINC01482077, and ZINC03830976 induced a slight structural change and stabilized the PDXK structure. This analysis provided valuable information about the critical residues involved in the PDXK-PLP complex formation and can be utilized in designing specific and effective PDXK inhibitors. According to this study, these compounds could be developed as anticancer agents targeting PDXK as a potential candidate for further study.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Pallabi Banerjee
- School of Biotechnology, Gautam Buddha University, Greater Noida, India
| | - Anshuman Chandra
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Nagendra Singh
- School of Biotechnology, Gautam Buddha University, Greater Noida, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Imteyaz Qamar
- School of Biotechnology, Gautam Buddha University, Greater Noida, India
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11
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Pearl PL, Tokatly Latzer I, Lee HHC, Rotenberg A. New Therapeutic Approaches to Inherited Metabolic Pediatric Epilepsies. Neurology 2023; 101:124-133. [PMID: 36878704 PMCID: PMC10382274 DOI: 10.1212/wnl.0000000000207133] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/17/2023] [Indexed: 03/08/2023] Open
Abstract
Treatment options for inherited metabolic epilepsies are rapidly expanding with advances in molecular biology and the genomic revolution. Traditional dietary and nutrient modification and inhibitors or enhancers of protein and enzyme function, the mainstays of therapy, are undergoing continuous revisions to increase biological activity and reduce toxicity. Enzyme replacement and gene replacement and editing hold promise for genetically targeted treatment and cures. Molecular, imaging, and neurophysiologic biomarkers are emerging as key indicators of disease pathophysiology, severity, and response to therapy.
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Affiliation(s)
- Phillip L Pearl
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA.
| | - Itay Tokatly Latzer
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Henry H C Lee
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Alexander Rotenberg
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA
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Elucidating the Interaction between Pyridoxine 5'-Phosphate Oxidase and Dopa Decarboxylase: Activation of B6-Dependent Enzyme. Int J Mol Sci 2022; 24:ijms24010642. [PMID: 36614085 PMCID: PMC9820991 DOI: 10.3390/ijms24010642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
Pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, serves as a cofactor for scores of B6-dependent (PLP-dependent) enzymes involved in many cellular processes. One such B6 enzyme is dopa decarboxylase (DDC), which is required for the biosynthesis of key neurotransmitters, e.g., dopamine and serotonin. PLP-dependent enzymes are biosynthesized as apo-B6 enzymes and then converted to the catalytically active holo-B6 enzymes by Schiff base formation between the aldehyde of PLP and an active site lysine of the protein. In eukaryotes, PLP is made available to the B6 enzymes through the activity of the B6-salvage enzymes, pyridoxine 5'-phosphate oxidase (PNPO) and pyridoxal kinase (PLK). To minimize toxicity, the cell keeps the content of free PLP (unbound) very low through dephosphorylation and PLP feedback inhibition of PNPO and PLK. This has led to a proposed mechanism of complex formation between the B6-salvage enzymes and apo-B6 enzymes prior to the transfer of PLP, although such complexes are yet to be characterized at the atomic level, presumably due to their transient nature. A computational study, for the first time, was used to predict a likely PNPO and DDC complex, which suggested contact between the allosteric PLP tight-binding site on PNPO and the active site of DDC. Using isothermal calorimetry and/or surface plasmon resonance, we also show that PNPO binds both apoDDC and holoDDC with dissociation constants of 0.93 ± 0.07 μM and 2.59 ± 0.11 μM, respectively. Finally, in the presence of apoDDC, the tightly bound PLP on PNPO is transferred to apoDDC, resulting in the formation of about 35% holoDDC.
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Validated UPLC-MS/MS method for the analysis of vitamin B6 pyridoxal 5́-phosphate, pyridoxal, pyridoxine, pyridoxamine, and pyridoxic acid in human cerebrospinal fluid. J Chromatogr B Analyt Technol Biomed Life Sci 2022; 1212:123503. [DOI: 10.1016/j.jchromb.2022.123503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/23/2022] [Accepted: 10/09/2022] [Indexed: 11/05/2022]
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14
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Stolwijk NN, Brands MM, Smit LS, van der Wel V, Hollak CEM, van Karnebeek CD. A vitamin a day keeps the doctor away: The need for high quality pyridoxal-5'-phosphate. Eur J Paediatr Neurol 2022; 39:25-29. [PMID: 35636100 DOI: 10.1016/j.ejpn.2022.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/21/2022] [Accepted: 04/28/2022] [Indexed: 12/17/2022]
Abstract
BACKGROUND A rare subset of vitamin B6 responsive seizure disorders does not respond to pyridoxine, and requires the active form of vitamin B6, pyridoxal-5'-phosphate (PLP), to maintain seizure control. Patients with PLP-responsive seizures are dependent on chronic PLP treatment, yet no licensed PLP product is available. PLP food supplements, a product category regulated less stringently than medication, may prove of insufficient effectiveness and safety. Here we describe and discuss three patient scenarios which illustrate this conundrum. METHODS Medical and laboratory records were reviewed with retrospective extraction for three unrelated patients who suffered complications during treatment with PLP food supplements. RESULTS - Two cases of PNPO deficiency and one case of PLP-dependent epileptic encephalopathy without a (genetic) diagnosis are reported. These patients are critically dependent on PLP for seizure control and have suffered complications due to insufficient quality of these food supplements during the course of treatment. Complications include the occurrence of seizures following the administration of suspected low quality PLP, inactive PLP due to light exposure, a PLP intoxication, resisting administration and post-administration vomiting as a result of the ingestion of large amounts of capsules per day. CONCLUSION - This case series illustrates that the reliance on food supplements as anti-seizure therapy is not without risk. The treatment of PLP-dependent seizures exemplifies that PLP is administered as medication, thus there is a clear need for licensed vitamin products of pharmaceutical quality.
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Affiliation(s)
- N N Stolwijk
- Medicine for Society, Platform at Amsterdam University Medical Center - University of Amsterdam, the Netherlands; Department of Endocrinology and Metabolism, Amsterdam University Medical Center - University of Amsterdam, the Netherlands
| | - M M Brands
- Department of Pediatrics & Human Genetics, Emma Children's Hospital, Amsterdam University Medical Center, University of Amsterdam, the Netherlands; United for Metabolic Diseases, the Netherlands
| | - L S Smit
- Department of Neurology, Division of Pediatric Neurology, Sophia Children's Hospital, Erasmus Medical Center, Rotterdam, the Netherlands
| | - V van der Wel
- Medicine for Society, Platform at Amsterdam University Medical Center - University of Amsterdam, the Netherlands
| | - C E M Hollak
- Medicine for Society, Platform at Amsterdam University Medical Center - University of Amsterdam, the Netherlands; Department of Endocrinology and Metabolism, Amsterdam University Medical Center - University of Amsterdam, the Netherlands; United for Metabolic Diseases, the Netherlands
| | - C D van Karnebeek
- Department of Pediatrics & Human Genetics, Emma Children's Hospital, Amsterdam University Medical Center, University of Amsterdam, the Netherlands; United for Metabolic Diseases, the Netherlands; Emma Center for Personalized Medicine, Amsterdam Reproduction and Development, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.
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15
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Pearl PL. Urgent unmet need for pharmaceutical grade vitamin therapy in pyridoxine dependent epilepsies. Eur J Paediatr Neurol 2022; 39:A3. [PMID: 35732574 DOI: 10.1016/j.ejpn.2022.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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16
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Adesoji OM, Schulz H, May P, Krause R, Lerche H, Nothnagel M. Benchmarking of univariate pleiotropy detection methods applied to epilepsy. Hum Mutat 2022; 43:1314-1332. [PMID: 35620985 DOI: 10.1002/humu.24417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/28/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022]
Abstract
Pleiotropy is a widespread phenomenon that may increase insight into the etiology of biological and disease traits. Since genome-wide association studies frequently provide information on a single trait only, only univariate pleiotropy detection methods are applicable, with yet unknown comparative performance. Here, we compared five such methods with respect to their ability to detect pleiotropy, including meta-analysis, ASSET, cFDR, CPBayes, and PLACO, by performing extended computer simulations that varied the underlying etiological model for pleiotropy for a pair of traits, including the number of causal variants, degree of traits' overlap, effect sizes as well as trait prevalence, and varying sample sizes. Our results indicate that ASSET provides the best trade-off between power and protection against false positives. We then applied ASSET to a previously published ILAE consortium dataset on complex epilepsies, comprising genetic generalized epilepsy and focal epilepsy cases and corresponding controls. We identified a novel candidate locus at 17q21.32 and confirmed locus 2q24.3, previously identified to act pleiotropically on both epilepsy subtypes by a mega-analysis. Functional annotation, tissue-specific expression and regulatory function analysis as well as Bayesian co-localization analysis corroborated this result, rendering 17q21.32 a worthwhile candidate for follow-up studies on pleiotropy in epilepsies. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Oluyomi M Adesoji
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,University Hospital Cologne, Medical Faculty, University of Cologne, Cologne, Germany
| | - Herbert Schulz
- Department of Microgravity and Translational Regenerative Medicine, Clinic of Plastic, Aesthetic and Hand Surgery, Otto von Guericke University, Magdeburg, Germany
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Michael Nothnagel
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,University Hospital Cologne, Medical Faculty, University of Cologne, Cologne, Germany
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17
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Jiao X, Gong P, Niu Y, Xu Z, Wu Y, Zhang Y, Yang Z. The Clinical Features and Long-Term Follow-Up of Vitamin B6-Responsive Infantile Spasms in a Chinese Cohort. Front Neurol 2022; 13:895978. [PMID: 35645976 PMCID: PMC9134116 DOI: 10.3389/fneur.2022.895978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/21/2022] [Indexed: 11/22/2022] Open
Abstract
Objective To analyze the clinical features, treatment, and prognosis of patients with vitamin B6-responsive infantile spasms (IS). Methods The clinical features, genetics, and follow-up data of 30 patients were collected and analyzed. Results The age of epileptic spasms (ES) onset was from 3 months to 12 months. They all received high doses of vitamin B6 at different times after the onset of ES, ranging from 1 day to 5 months. ES were controlled within 11 days in 93% (28/30) patients, and as late as 1 month and 2 months in the other two patients. In the course of treatment, 28 patients were seizure-free all the time, and seizures of other two patients recurred due to withdrawal of vitamin B6. The available follow-up EEG results of 28 patients were normal in 26 cases, and 81% (21/26) had suppressed epileptic discharges within 6 months. Of the 26 cases with normal follow up EEG, 4 had developmental delay and 22 had normal development. The time for EEG to return to normal in 22 patients with normal development ranged from 14 days to 2 years (mean = 111.5 days; median = 52.5 days). The time for EEG to return to normal in the other 4 patients with development delay ranged from 4 months to 2 years (mean = 375 days; median = 330 days). To the last follow-up, seizures were controlled well in 29 surviving patients, and 21 patients were able to deactivate from all medications without seizures recurrence. Sixteen patients showed varying degrees of developmental delay after onset. After seizure control, the psychomotor development was delayed in 7 patients (one died) until the last follow-up. Genetic analysis did not show any meaningful results. Conclusion An observation period of 1–2 weeks is essential to identify patients with vitamin B6-responsive IS. The treatment time could be extended according to the treatment response and EEG changes. It might take a longer time for EEG to return to normal and to stop taking drugs in patients with persistent or unimproved developmental delay. Neurodevelopmental outcomes and prognosis of vitamin B6-responsive IS were relatively favorable.
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18
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Zuberi SM, Wirrell E, Yozawitz E, Wilmshurst JM, Specchio N, Riney K, Pressler R, Auvin S, Samia P, Hirsch E, Galicchio S, Triki C, Snead OC, Wiebe S, Cross JH, Tinuper P, Scheffer IE, Perucca E, Moshé SL, Nabbout R. ILAE classification and definition of epilepsy syndromes with onset in neonates and infants: Position statement by the ILAE Task Force on Nosology and Definitions. Epilepsia 2022; 63:1349-1397. [PMID: 35503712 DOI: 10.1111/epi.17239] [Citation(s) in RCA: 220] [Impact Index Per Article: 110.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 12/20/2022]
Abstract
The International League Against Epilepsy (ILAE) Task Force on Nosology and Definitions proposes a classification and definition of epilepsy syndromes in the neonate and infant with seizure onset up to 2 years of age. The incidence of epilepsy is high in this age group and epilepsy is frequently associated with significant comorbidities and mortality. The licensing of syndrome specific antiseizure medications following randomized controlled trials and the development of precision, gene-related therapies are two of the drivers defining the electroclinical phenotypes of syndromes with onset in infancy. The principal aim of this proposal, consistent with the 2017 ILAE Classification of the Epilepsies, is to support epilepsy diagnosis and emphasize the importance of classifying epilepsy in an individual both by syndrome and etiology. For each syndrome, we report epidemiology, clinical course, seizure types, electroencephalography (EEG), neuroimaging, genetics, and differential diagnosis. Syndromes are separated into self-limited syndromes, where there is likely to be spontaneous remission and developmental and epileptic encephalopathies, diseases where there is developmental impairment related to both the underlying etiology independent of epileptiform activity and the epileptic encephalopathy. The emerging class of etiology-specific epilepsy syndromes, where there is a specific etiology for the epilepsy that is associated with a clearly defined, relatively uniform, and distinct clinical phenotype in most affected individuals as well as consistent EEG, neuroimaging, and/or genetic correlates, is presented. The number of etiology-defined syndromes will continue to increase, and these newly described syndromes will in time be incorporated into this classification. The tables summarize mandatory features, cautionary alerts, and exclusionary features for the common syndromes. Guidance is given on the criteria for syndrome diagnosis in resource-limited regions where laboratory confirmation, including EEG, MRI, and genetic testing, might not be available.
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Affiliation(s)
- Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Institute of Health & Wellbeing, Collaborating Centre of European Reference Network EpiCARE, University of Glasgow, Glasgow, UK
| | - Elaine Wirrell
- Divisions of Child and Adolescent Neurology and Epilepsy, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Elissa Yozawitz
- Isabelle Rapin Division of Child Neurology, Saul R. Korey Department of Neurology, Montefiore Medical Center, Bronx, New York, USA
| | - Jo M Wilmshurst
- Department of Paediatric Neurology, Red Cross War Memorial Children's Hospital, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesu' Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Kate Riney
- Neurosciences Unit, Queensland Children's Hospital, South Brisbane, Queensland, Australia.,Faculty of Medicine, University of Queensland, St Lucia, Queensland, Australia
| | - Ronit Pressler
- Clinical Neuroscience, UCL- Great Ormond Street Institute of Child Health, London, UK.,Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Member of European Reference Network EpiCARE, London, UK
| | - Stephane Auvin
- AP-HP, Hôpital Robert-Debré, INSERM NeuroDiderot, DMU Innov-RDB, Neurologie Pédiatrique, Member of European Reference Network EpiCARE, Université de Paris, Paris, France
| | - Pauline Samia
- Department of Paediatrics and Child Health, Aga Khan University, Nairobi, Kenya
| | - Edouard Hirsch
- Neurology Epilepsy Unit "Francis Rohmer", INSERM 1258, FMTS, Strasbourg University, Strasbourg, France
| | - Santiago Galicchio
- Child Neurology Department, Victor J Vilela Child Hospital of Rosario, Santa Fe, Argentina
| | - Chahnez Triki
- Child Neurology Department, LR19ES15 Neuropédiatrie, Sfax Medical School, University of Sfax, Sfax, Tunisia
| | - O Carter Snead
- Pediatric Neurology, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Samuel Wiebe
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - J Helen Cross
- Programme of Developmental Neurosciences, UCL NIHR BRC Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, Member of European Reference Network EpiCARE, London, UK.,Young Epilepsy, Lingfield, UK
| | - Paolo Tinuper
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy
| | - Ingrid E Scheffer
- Austin Health and Royal Children's Hospital, Florey Institute, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Emilio Perucca
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - Solomon L Moshé
- Isabelle Rapin Division of Child Neurology, Saul R. Korey Department of Neurology, Bronx, New York, USA.,Departments of Neuroscience and Pediatrics, Albert Einstein College of Medicine, Bronx, New York, USA.,Montefiore Medical Center, Bronx, New York, USA
| | - Rima Nabbout
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker-Enfants Malades University Hospital, APHP, Member of European Reference Network EpiCARE, Institut Imagine, INSERM, UMR 1163, Université Paris cité, Paris, France
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Jiao X, Gong P, Niu Y, Zhang Y, Yang Z. A Rare Presentation Characterized by Epileptic Spasms in ALDH7A1, Pyridox(am)ine-5′-Phosphate Oxidase, and PLPBP Deficiency. Front Genet 2022; 13:804461. [PMID: 35495162 PMCID: PMC9039010 DOI: 10.3389/fgene.2022.804461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/07/2022] [Indexed: 11/25/2022] Open
Abstract
Objective: To analyze the clinical feature, treatment, and prognosis of epileptic spasms (ES) in vitamin B6–dependent epilepsy, including patients with pyridoxine-dependent epilepsy (PDE) caused by ALDH7A1 mutation, pyridox(am)ine-5′-phosphate oxidase (PNPO) deficiency, and PLPBP deficiency. Methods: We analyzed data from a cohort of 54 cases with PDE, 13 cases with PNPO deficiency, and 2 cases with PLPBP deficiency and looked for the presentation of ES among them. Results: A total of 11 patients with the seizure presentation of ES have been collected. Among them, four patients carried mutations in ALDH7A1, six carried mutations in PNPO, and the remaining one carried mutation in PLPBP. The analysis of this cohort identified nine cases presenting as infantile spasms distributed in the three diseases and two cases presenting as Ohtahara syndrome diagnosed with PDE and PNPO deficiency, respectively. In the PDE and PLPBP deficiency groups, seizures were controlled by pyridoxine monotherapy, and the remaining one had refractory seizures due to secondary brain atrophy. In the groups with PNPO deficiency, one patient showed seizure-free when treated by PLP combined with valproic acid, three still had infrequent seizures treated by PLP monotherapy or pyridoxine or PLP combined with other antiseizure medications, and two died. In two cases presenting as Ohtahara syndrome, after regular treatment, one showed seizure-free, the others showed a marked decrease in seizure frequency, and they both showed an improvement in EEG. Significance: ES might be a common form of seizures in PNPO deficiency, and EEG presented as hypsarrhythmia or a burst suppression pattern. It is difficult for pyridoxine to control frequent seizures caused by secondary brain injury. In our PNPO deficiency cohort, patients with infantile spasms did not respond better to PLP than pyridoxine. Timely and correct treatment could prevent the transformation of the child’s disease from Ohtahara syndrome and infantile spasms to subsequent epileptic encephalopathy or refractory epilepsy.
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Abstract
The brain is a highly energy-demanding organ and requires bioenergetic adaptability to balance normal activity with pathophysiological fuelling of spontaneous recurrent seizures, the hallmark feature of the epilepsies. Recurrent or prolonged seizures have long been known to permanently alter neuronal circuitry and to cause excitotoxic injury and aberrant inflammation. Furthermore, pathological changes in bioenergetics and metabolism are considered downstream consequences of epileptic seizures that begin at the synaptic level. However, as we highlight in this Review, evidence is also emerging that primary derangements in cellular or mitochondrial metabolism can result in seizure genesis and lead to spontaneous recurrent seizures. Basic and translational research indicates that the relationships between brain metabolism and epileptic seizures are complex and bidirectional, producing a vicious cycle that compounds the deleterious consequences of seizures. Metabolism-based treatments such as the high-fat, antiseizure ketogenic diet have become mainstream, and metabolic substrates and enzymes have become attractive molecular targets for seizure prevention and recovery. Moreover, given that metabolism is crucial for epigenetic as well as inflammatory changes, the idea that epileptogenesis can be both negatively and positively influenced by metabolic changes is rapidly gaining ground. Here, we review evidence that supports both pathophysiological and therapeutic roles for brain metabolism in epilepsy.
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Drosophila carrying epilepsy-associated variants in the vitamin B6 metabolism gene PNPO display allele- and diet-dependent phenotypes. Proc Natl Acad Sci U S A 2022; 119:2115524119. [PMID: 35217610 PMCID: PMC8892510 DOI: 10.1073/pnas.2115524119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2022] [Indexed: 12/02/2022] Open
Abstract
Both genetic and environmental factors contribute to epilepsy. Understanding their contributions and interactions helps disease management. However, it is often challenging to study gene–environment interaction in humans due to their heterogeneous genetic background and less controllable environmental factors. The fruit fly, Drosophila melanogaster, has been proven to be a powerful model to study human diseases, including epilepsy. We generated knock-in flies carrying different epilepsy-associated pyridox(am)ine 5′-phosphate oxidase (PNPO) alleles and studied the developmental, behavioral, electrophysiological, and fitness effects of each mutant allele under different dietary conditions. We showed that phenotypes in knock-in flies are allele and diet dependent, providing clues for timely and specific diet interventions. Our results offer biological insights into mechanisms underlying phenotypic variations and specific therapeutic strategies. Pyridox(am)ine 5′-phosphate oxidase (PNPO) catalyzes the rate-limiting step in the synthesis of pyridoxal 5′-phosphate (PLP), the active form of vitamin B6 required for the synthesis of neurotransmitters gamma-aminobutyric acid (GABA) and the monoamines. Pathogenic variants in PNPO have been increasingly identified in patients with neonatal epileptic encephalopathy and early-onset epilepsy. These patients often exhibit different types of seizures and variable comorbidities. Recently, the PNPO gene has also been implicated in epilepsy in adults. It is unclear how these phenotypic variations are linked to specific PNPO alleles and to what degree diet can modify their expression. Using CRISPR-Cas9, we generated four knock-in Drosophila alleles, hWT, hR116Q, hD33V , and hR95H, in which the endogenous Drosophila PNPO was replaced by wild-type human PNPO complementary DNA (cDNA) and three epilepsy-associated variants. We found that these knock-in flies exhibited a wide range of phenotypes, including developmental impairments, abnormal locomotor activities, spontaneous seizures, and shortened life span. These phenotypes are allele dependent, varying with the known biochemical severity of these mutations and our characterized molecular defects. We also showed that diet treatments further diversified the phenotypes among alleles, and PLP supplementation at larval and adult stages prevented developmental impairments and seizures in adult flies, respectively. Furthermore, we found that hR95H had a significant dominant-negative effect, rendering heterozygous flies susceptible to seizures and premature death. Together, these results provide biological bases for the various phenotypes resulting from multifunction of PNPO, specific molecular and/or genetic properties of each PNPO variant, and differential allele–diet interactions.
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22
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Zhang L, Li X, Zhang J, Xu G. Prognostic Implication and Oncogenic Role of PNPO in Pan-Cancer. Front Cell Dev Biol 2022; 9:763674. [PMID: 35127701 PMCID: PMC8814662 DOI: 10.3389/fcell.2021.763674] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/17/2021] [Indexed: 12/12/2022] Open
Abstract
Objective: Pyridoxine 5′-phosphate oxidase (PNPO) is a key enzyme in the metabolism of vitamin B6 and affects the tumorigenesis of ovarian and breast cancers. However, the roles of PNPO in other types of cancer remain unknown.Methods: The expression of PNPO was interpreted by The Cancer Genome Atlas (TCGA) database and Genotype Tissue-Expression (GTEX) database. Analysis of PNPO genomic alterations and protein expression in human organic tissues was analyzed by the cBioPortal database and human multiple organ tissue arrays. PNPO with drug sensitivity analysis was performed from the CellMiner database. The correlations between PNPO expression and survival outcomes, clinical features, DNA mismatch repair system (MMR), microsatellite instability (MSI), tumor mutation burden (TMB), and immune-associated cell infiltration were analyzed using the TCGA, ESTIMATE algorithm, and TIMER databases. Gene Set Enrichment Analysis (GSEA) was applied to elucidate the biological function of PNPO in pan-cancer.Results: The differential analysis showed that the level of PNPO mRNA expression was upregulated in 21 tumor types compared with normal tissues, which was consistent with its protein expression in most cancer types. The abnormal expression of PNPO could predict the survival outcome of patients with esophageal carcinoma (ESCA), kidney renal clear cell carcinoma (KIRC), prostate adenocarcinoma (PRAD), ovarian serous cystadenocarcinoma (OV), and uveal melanoma (UVM). Furthermore, the most frequent mutation type of PNPO genomic was amplified. Moreover, the aberrant PNPO expression was related to MMR, MSI, TMB, and drug sensitivity in various types of cancer. The expression of PNPO was related to the infiltration levels of various immune-associated cells in pan-cancer by ESTIMATE algorithm and TIMER database mining.Conclusion: Our results suggest that PNPO is a potential molecular biomarker for predicting patient prognosis, drug sensitivity, and immunoreaction in pan-cancer.
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Affiliation(s)
- Lingyun Zhang
- Department of Medical Oncology, Zhongshan Hospital, Fudan University, Shanghai, China
- Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China
- Center of Evidence-Based Medicine, Fudan University, Shanghai, China
- *Correspondence: Guoxiong Xu, ; Lingyun Zhang,
| | - Xin Li
- Research Center for Clinical Medicine, Jinshan Hospital, Fudan University, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jinguo Zhang
- Department of Medical Oncology, The First Affiliated Hospital of University of Science and Technology of China, Hefei, China
| | - Guoxiong Xu
- Research Center for Clinical Medicine, Jinshan Hospital, Fudan University, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- *Correspondence: Guoxiong Xu, ; Lingyun Zhang,
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Mechanism of pyridoxine 5'-phosphate accumulation in PLPBP protein-deficiency. J Bacteriol 2022; 204:e0052121. [PMID: 34978460 DOI: 10.1128/jb.00521-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pyridoxal 5'-phosphate (PLP)-binding protein (PLPBP) plays an important role in vitamin B6 homeostasis. Loss of this protein in organisms such as Escherichia coli and humans disrupts the vitamin B6 pool and induces intracellular accumulation of pyridoxine 5'-phosphate (PNP), which is normally undetectable in wild-type cells. The accumulated PNP could affect diverse metabolic systems through inhibition of some PLP-dependent enzymes. In this study, we investigated the as yet unclear mechanism of intracellular accumulation of PNP by the loss of PLPBP protein encoded by yggS in E. coli. Genetic studies using several PLPBP-deficient strains of E. coli lacking known enzyme(s) in the de novo or salvage pathway of vitamin B6, which includes pyridoxine (amine) 5'-phosphate oxidase (PNPO), PNP synthase, pyridoxal kinase, and pyridoxal reductase, demonstrated that neither the flux from the de novo pathway nor the salvage pathway solely contributed to the PNP accumulation caused by the PLPBP mutation. Studies with the strains lacking both PLPBP and PNPO suggested that PNP shares the same pool with PMP, and showed that PNP levels are impacted by PMP levels and vice versa. We show that disruption of PLPBP lead to perturb PMP homeostasis, which may result in PNP accumulation in the PLPBP-deficient strains. Importance A PLP-binding protein PLPBP from the conserved COG0325 family has recently been recognized as a key player in vitamin B6 homeostasis in various organisms. Loss of PLPBP disrupts vitamin B6 homeostasis and perturbs diverse metabolisms, including amino acid and α-keto acid metabolism. Accumulation of PNP is a characteristic phenotype of the PLPBP deficiency and is suggested to be a potential cause of the pleiotropic effects, but the mechanism of the PNP accumulation was poorly understood. In this study, we show that fluxes for PNP synthesis/metabolism are not responsible for the accumulation of PNP. Our results indicate that PLPBP is involved in the homeostasis of pyridoxamine 5'-phosphate, and its disruption may lead to the accumulation of PNP in PLPBP-deficiency.
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McGinn RJ, Von Stein EL, Summers Stromberg JE, Li Y. Precision medicine in epilepsy. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 190:147-188. [DOI: 10.1016/bs.pmbts.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Aquilano G, Linnér A, Ygberg S, Stödberg T, Henckel E. Case report: Fatal outcome of pyridoxine-dependent epilepsy presenting as respiratory distress followed by a circulatory collapse. Front Pediatr 2022; 10:940103. [PMID: 35967578 PMCID: PMC9366515 DOI: 10.3389/fped.2022.940103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Pyridoxine-dependent epilepsy is a rare autosomal recessive disease usually associated with neonatal seizures that do not respond to common antiseizure medications but are controlled by pyridoxine administration. Because the symptoms can mimic common neonatal disorders, the diagnosis can be initially missed or delayed. We report a fatal case of a boy who was initially diagnosed with respiratory distress, birth asphyxia, and persistent pulmonary hypertension and whose condition rapidly deteriorated during the first day of life.
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Affiliation(s)
- Giulia Aquilano
- Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden
| | - Agnes Linnér
- Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Sofia Ygberg
- Department of Child Neurology, Karolinska University Hospital, Stockholm, Sweden.,Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Center for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Stockholm, Sweden
| | - Tommy Stödberg
- Department of Child Neurology, Karolinska University Hospital, Stockholm, Sweden.,Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Ewa Henckel
- Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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Characterization of Novel Pathogenic Variants Causing Pyridox(am)ine 5'-Phosphate Oxidase-Dependent Epilepsy. Int J Mol Sci 2021; 22:ijms222112013. [PMID: 34769443 PMCID: PMC8584306 DOI: 10.3390/ijms222112013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 11/17/2022] Open
Abstract
Several variants of the enzyme pyridox(am)ine 5′-phosphate oxidase (PNPO), responsible for a rare form of vitamin B6-dependent neonatal epileptic encephalopathy known as PNPO deficiency (PNPOD), have been reported. However, only a few of them have been characterised with respect to their structural and functional properties, despite the fact that the knowledge of how variants affect the enzyme may clarify the disease mechanism and improve treatment. Here, we report the characterisation of the catalytic, allosteric and structural properties of recombinantly expressed D33V, R161C, P213S, and E50K variants, among which D33V (present in approximately 10% of affected patients) is one of the more common variants responsible for PNPOD. The D33V and E50K variants have only mildly altered catalytic properties. In particular, the E50K variant, given that it has been found on the same chromosome with other known pathogenic variants, may be considered non-pathogenic. The P213S variant has lower thermal stability and reduced capability to bind the FMN cofactor. The variant involving Arg161 (R161C) largely decreases the affinity for the pyridoxine 5′-phosphate substrate and completely abolishes the allosteric feedback inhibition exerted by the pyridoxal 5′-phosphate product.
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Abstract
Inborn errors of metabolism have been considered as an infrequent cause of epilepsy. Improvement in diagnostics has improved the detection of a metabolic basis of recurrent seizures in neonates and children. The term 'metabolic epilepsy' is used to suggest inherited metabolic disorders with predominant epileptic manifestations as well as those where epilepsy is part of the overall neurological phenotype. Several of these disorders are treatable, and the physician should bear in mind the classical ages of presentation. As there are no specific clinical or electrographic features suggestive of metabolic epilepsies, an early suspicion is based on clinical and laboratory clues. Fortunately, with the advancement of gene sequencing technology, a diagnosis of these rare conditions is more straightforward and may not require invasive procedures such as biopsies, multiple metabolic stress-induced testing for abnormalities, and cerebrospinal fluid analysis. A gene panel may suffice in most cases and can be done from a blood sample. In many countries, many treatable metabolic disorders are now part of the neonatal screen. Early diagnosis and treatment of these disorders can result in the prevention of a full-scale metabolic crisis and improvement of neurological outcomes. Long-term neurological outcomes are variable and additional therapies may be required.
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Myers KA, Scheffer IE. Precision Medicine Approaches for Infantile-Onset Developmental and Epileptic Encephalopathies. Annu Rev Pharmacol Toxicol 2021; 62:641-662. [PMID: 34579535 DOI: 10.1146/annurev-pharmtox-052120-084449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epilepsy is an etiologically heterogeneous condition; however, genetic factors are thought to play a role in most patients. For those with infantile-onset developmental and epileptic encephalopathy (DEE), a genetic diagnosis is now obtained in more than 50% of patients. There is considerable motivation to utilize these molecular diagnostic data to help guide treatment, as children with DEEs often have drug-resistant seizures as well as developmental impairment related to cerebral epileptiform activity. Precision medicine approaches have the potential to dramatically improve the quality of life for these children and their families. At present, treatment can be targeted for patients with diagnoses in many genetic causes of infantile-onset DEE, including genes encoding sodium or potassium channel subunits, tuberous sclerosis, and congenital metabolic diseases. Precision medicine may refer to more intelligent choices of conventional antiseizure medications, repurposed agents previously used for other indications, novel compounds, enzyme replacement, or gene therapy approaches. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Kenneth A Myers
- Research Institute of the McGill University Health Centre, Division of Child Neurology, Department of Pediatrics, and Department of Neurology and Neurosurgery, Montreal Children's Hospital, McGill University, Montreal, Quebec H4A 3J1, Canada;
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria 3084, Australia; .,Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Parkville, Victoria 3052, Australia.,The Florey Institute of Neuroscience and Mental Health and Murdoch Children's Research Institute, Parkville, Victoria 3052, Australia
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29
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New avenues in molecular genetics for the diagnosis and application of therapeutics to the epilepsies. Epilepsy Behav 2021; 121:106428. [PMID: 31400936 DOI: 10.1016/j.yebeh.2019.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/14/2019] [Accepted: 07/06/2019] [Indexed: 11/22/2022]
Abstract
Genetic epidemiology studies have shown that most epilepsies involve some genetic cause. In addition, twin studies have helped strengthen the hypothesis that in most patients with epilepsy, a complex inheritance is involved. More recently, with the development of high-density single-nucleotide polymorphism (SNP) microarrays and next-generation sequencing (NGS) technologies, the discovery of genes related to the epilepsies has accelerated tremendously. Especially, the use of whole exome sequencing (WES) has had a considerable impact on the identification of rare genetic variants with large effect sizes, including inherited or de novo mutations in severe forms of childhood epilepsies. The identification of pathogenic variants in patients with these childhood epilepsies provides many benefits for patients and families, such as the confirmation of the genetic nature of the diseases. This process will allow for better genetic counseling, more accurate therapy decisions, and a significant positive emotional impact. However, to study the genetic component of the more common forms of epilepsy, the use of high-density SNP arrays in genome-wide association studies (GWAS) seems to be the strategy of choice. As such, researchers can identify loci containing genetic variants associated with the common forms of epilepsy. The knowledge generated over the past two decades about the effects of the mutations that cause the monogenic epilepsy is tremendous; however, the scientific community is just starting to apply this information in order to generate better target treatments.
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Hadtstein F, Vrolijk M. Vitamin B-6-Induced Neuropathy: Exploring the Mechanisms of Pyridoxine Toxicity. Adv Nutr 2021; 12:1911-1929. [PMID: 33912895 PMCID: PMC8483950 DOI: 10.1093/advances/nmab033] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 12/26/2022] Open
Abstract
Vitamin B-6 in the form of pyridoxine (PN) is commonly used by the general population. The use of PN-containing supplements has gained lots of attention over the past years as they have been related to the development of peripheral neuropathy. In light of this, the number of reported cases of adverse health effects due to the use of vitamin B-6 have increased. Despite a long history of study, the pathogenic mechanisms associated with PN toxicity remain elusive. Therefore, the present review is focused on investigating the mechanistic link between PN supplementation and sensory peripheral neuropathy. Excessive PN intake induces neuropathy through the preferential injury of sensory neurons. Recent reports on hereditary neuropathy due to pyridoxal kinase (PDXK) mutations may provide some insight into the mechanism, as genetic deficiencies in PDXK lead to the development of axonal sensory neuropathy. High circulating concentrations of PN may lead to a similar condition via the inhibition of PDXK. The mechanism behind PDXK-induced neuropathy is unknown; however, there is reason to believe that it may be related to γ-aminobutyric acid (GABA) neurotransmission. Compounds that inhibit PDXK lead to convulsions and reductions in GABA biosynthesis. The absence of central nervous system-related symptoms in PDXK deficiency could be due to differences in the regulation of PDXK, where PDXK activity is preserved in the brain but not in peripheral tissues. As PN is relatively impermeable to the blood-brain barrier, PDXK inhibition would similarly be confined to the peripheries and, as a result, GABA signaling may be perturbed within peripheral tissues, such as sensory neurons. Perturbed GABA signaling within sensory neurons may lead to excitotoxicity, neurodegeneration, and ultimately, the development of peripheral neuropathy. For several reasons, we conclude that PDXK inhibition and consequently disrupted GABA neurotransmission is the most plausible mechanism of toxicity.
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Affiliation(s)
- Felix Hadtstein
- University College Venlo, Campus Venlo, Maastricht University, Maastricht, The Netherlands
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Wassenberg T, Geurtz BPH, Monnens L, Wevers RA, Willemsen MA, Verbeek MM. Blood, urine and cerebrospinal fluid analysis in TH and AADC deficiency and the effect of treatment. Mol Genet Metab Rep 2021; 27:100762. [PMID: 33996491 PMCID: PMC8093927 DOI: 10.1016/j.ymgmr.2021.100762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 12/03/2022] Open
Abstract
Background Aromatic L-amino acid decarboxylase (AADC) deficiency and tyrosine hydroxylase (TH) deficiency are rare inherited disorders of monoamine neurotransmitter synthesis which are typically diagnosed using cerebrospinal fluid examination of monoamine neurotransmitter metabolites. Until now, it has not been systematically studied whether analysis of monamine neurotransmitter metabolites in blood or urine has diagnostic value as compared to cerebrospinal fluid examination, or whether monoamine neurotransmitter metabolites in these peripheral body fluids is useful to monitor treatment efficacy. Methods Assessment, both by literature review and retrospective analysis of our local university hospital database, of monoamine neurotransmitter metabolites in urine, blood and cerebrospinal fluid, and serum prolactin levels, before and during treatment in patients with AADC and TH deficiency. Results In AADC deficiency, 3-O-methyldopa in serum or dried blood spots was reported in 34 patients and found to be (strongly) increased in all, serotonin in serum was decreased in 7/7 patients. Serum prolactin was increased in 34/37 and normal in 3 untreated patients. In urine, dopamine was normal or increased in 21/24 patients, 5-hydroxyindoleacetic acid was decreased in 9/10 patients, and vanillactic acid was increased in 19/20 patients. No significant changes were seen in monoamine neurotransmitter metabolites after medical treatment, except for an increase of homovanillic acid in urine and cerebrospinal fluid after levodopa therapy, sometimes even in absence of a clinical response. After gene therapy, cerebrospinal fluid homovanillic acid increased in most patients (8/12), but 5-hydroxyindoleacetic acid remained unchanged in 9/12 patients. In TH deficiency, serum prolactin was increased in 12/14 and normal in the remaining untreated patients. Urinary dopamine was decreased in 2/8 patients and normal in 6. Homovanillic acid concentrations in cerebrospinal fluid increased upon levodopa treatment, even in the absence of a clear treatment response. Conclusions This study confirms that cerebrospinal fluid is the most informative body fluid to measure monoamine neurotransmitter metabolites when AADC or TH deficiency is suspected, and that routine follow-up of cerebrospinal fluid measurements to estimate treatment response is not needed. 3-O-methyldopa in dried blood spots and vanillactic acid in urine are promising peripheral biomarkers for diagnosis of AADC deficiency. However, in many patients with TH or AADC deficiency dopamine in urine is normal or increased thereby not reflecting the metabolic block. The value of serum prolactin for follow-up of AADC and TH deficiency should be further studied.
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Key Words
- 3-OMD, 3-O-methyldopa
- 5-HIAA, 5-Hydroxyindoleacetic acid
- 5-HTP, 5-Hydroxytryptophan
- AADC deficiency
- AADC, Aromatic L-amino acid decarboxylase
- Aromatic L-amino acid decarboxylase deficiency
- Biomarkers
- CSF, Cerebrospinal fluid
- HVA, Homovanillic acid
- MHPG, 3-methoxy 4-hydroxyphenylglycol
- Monoamine neurotransmitter deficiency
- TH deficiency
- TH, Tyrosine hydroxylase
- TML, Translational Metabolic Laboratory
- Tyrosine hydroxylase deficiency
- VLA, Vanillactic acid
- VMA, Vanillylmandelic acid
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Affiliation(s)
- Tessa Wassenberg
- Radboud university medical center, Department of Neurology (943), Donders Institute for Brain, Cognition and Behaviour, PO Box 9101, 6500 HB, Nijmegen, the Netherlands.,Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Department of Pediatrics, Pediatric Neurology Unit, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Ben P H Geurtz
- Radboud university medical center, Department of Laboratory Medicine, Translational Metabolic Laboratory (830), PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Leo Monnens
- Radboud university medical center, Department of Physiology (392), PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Ron A Wevers
- Radboud university medical center, Department of Laboratory Medicine, Translational Metabolic Laboratory (830), PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Michèl A Willemsen
- Radboud university medical center, Amalia Children's Hospital, Department of Pediatric Neurology (801), Donders Institute for Brain, Cognition and Behaviour, PO Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Marcel M Verbeek
- Radboud university medical center, Department of Neurology (943), Donders Institute for Brain, Cognition and Behaviour, PO Box 9101, 6500 HB, Nijmegen, the Netherlands.,Radboud university medical center, Department of Laboratory Medicine, Translational Metabolic Laboratory (830), PO Box 9101, 6500 HB, Nijmegen, the Netherlands
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32
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Ghatge MS, Al Mughram M, Omar AM, Safo MK. Inborn errors in the vitamin B6 salvage enzymes associated with neonatal epileptic encephalopathy and other pathologies. Biochimie 2021; 183:18-29. [PMID: 33421502 DOI: 10.1016/j.biochi.2020.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/28/2022]
Abstract
Pyridoxal 5'-phosphate (PLP), the active cofactor form of vitamin B6 is required by over 160 PLP-dependent (vitamin B6) enzymes serving diverse biological roles, such as carbohydrates, amino acids, hemes, and neurotransmitters metabolism. Three key enzymes, pyridoxal kinase (PL kinase), pyridoxine 5'-phosphate oxidase (PNPO), and phosphatases metabolize and supply PLP to PLP-dependent enzymes through the salvage pathway. In born errors in the salvage enzymes are known to cause inadequate levels of PLP in the cell, particularly in neuronal cells. The resulting PLP deficiency is known to cause or implicated in several pathologies, most notably seizures. One such disorder, PNPO-dependent neonatal epileptic encephalopathy (NEE) results from natural mutations in PNPO and leads to null or reduced enzymatic activity. NEE does not respond to conventional antiepileptic drugs but may respond to treatment with the B6 vitamers PLP and/or pyridoxine (PN). In born errors that lead to PLP deficiency in cells have also been reported in PL kinase, however, to date none has been associated with epilepsy or seizure. One such pathology is polyneuropathy that responds to PLP therapy. Phosphatase deficiency or hypophosphatasia disorder due to pathogenic mutations in alkaline phosphatase is known to cause seizures that respond to PN therapy. In this article, we review the biochemical features of in born errors pertaining to the salvage enzyme's deficiency that leads to NEE and other pathologies. We also present perspective on vitamin B6 treatment for these disorders, along with attempts to develop zebrafish model to study the NEE syndrome in vivo.
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Affiliation(s)
- Mohini S Ghatge
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Mohammed Al Mughram
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Abdelsattar M Omar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanyah, Jeddah, 21589, Saudi Arabia; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Cairo, 11884, Egypt
| | - Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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Gibaud M, Barth M, Lefranc J, Mention K, Villeneuve N, Schiff M, Maurey H, Barthez MA, Caubel I, Chouchane M, Doummar D, Kossorotoff M, Lamblin MD, Roubertie A, Nabbout R, Van Bogaert P. West Syndrome Is an Exceptional Presentation of Pyridoxine- and Pyridoxal Phosphate-Dependent Epilepsy: Data From a French Cohort and Review of the Literature. Front Pediatr 2021; 9:621200. [PMID: 33748042 PMCID: PMC7973036 DOI: 10.3389/fped.2021.621200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 01/04/2021] [Indexed: 12/04/2022] Open
Abstract
Objective: To characterize the electro-clinical presentation of patients with pyridoxine-dependent epilepsy (PDE) and pyridoxal phosphate (PLP)-dependent epilepsy in order to determine whether some of them could be diagnosed as de novo West syndrome, i. e., West syndrome that starts after the age of 2 months without other types of seizures (focal seizures for instance) before the onset of epileptic spasms. Methods: We analyzed data from an unpublished cohort of 28 genetically confirmed cases of PDE with antiquitine (ATQ) deficiency and performed a review of the literature looking for description of West syndrome in patients with either PDE with ATQ deficiency or PLP-dependent epilepsy with Pyridox(am)ine phosphate oxidase (PNPO) deficiency. Results: Of the 28 cases from the ATQ deficiency French cohort, 5 had spasms. In four cases, spasms were associated with other types of seizures (myoclonus, focal seizures). In the last case, seizures started on the day of birth. None of these cases corresponded to de novo West syndrome. The review of the literature found only one case of PNPO deficiency presenting as de novo West syndrome and no case of ATQ deficiency. Significance: The presentation of PDE- and PLP-dependent epilepsy as de novo West syndrome is so exceptional that it probably does not justify a systematic trial of pyridoxine or PLP. We propose considering a therapeutic trial with these vitamins in West syndrome if spasms are associated with other seizure types or start before the age of 2 months.
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Affiliation(s)
- Marc Gibaud
- Service de neuropédiatrie, CHU d'Angers, Angers, France
| | - Magalie Barth
- Service de génétique médicale, CHU d'Angers, Angers, France
| | | | - Karine Mention
- Centre de référence des Maladies Héréditaires du métabolisme, Hôpital Jeanne de Flandre CHRU Lille, Lille, France
| | - Nathalie Villeneuve
- Service de neuropédiatrie, Hôpital de la Timone, APHM Marseille, Marseille, France
| | - Manuel Schiff
- Centre de référence maladies héréditaires du métabolisme Hôpital Robert Debré, APHP Paris, Paris, France
| | - Hélène Maurey
- Service de neuropédiatrie Hôpital Kremlin-Bicêtre APHP Paris, Paris, France
| | | | | | | | - Diane Doummar
- Service de neuropédiatrie, Hôpital d'Enfants Armand-Trousseau APHP Paris, Paris, France
| | - Manoëlle Kossorotoff
- Service de neuropédiatrie et maladies métaboliques, Hôpital Necker-Enfants Malades APHP Paris, Paris, France
| | - Marie-Dominique Lamblin
- Service de physiologie et explorations fonctionnelles, Hôpital Jeanne de Flandre CHRU Lille, Lille, France
| | - Agathe Roubertie
- Service de neuropédiatrie, CHU de Montpellier, Montpellier, France
| | - Rima Nabbout
- Service de neuropédiatrie et maladies métaboliques, Hôpital Necker-Enfants Malades APHP Paris, Paris, France
| | - Patrick Van Bogaert
- Service de neuropédiatrie, CHU d'Angers, Angers, France.,Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, Angers, France
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Akiyama T, Hyodo Y, Hasegawa K, Oboshi T, Imai K, Ishihara N, Dowa Y, Koike T, Yamamoto T, Shibasaki J, Shimbo H, Fukuyama T, Takano K, Shiraku H, Takeshita S, Okanishi T, Baba S, Kubota M, Hamano SI, Kobayashi K. Pyridoxal in the Cerebrospinal Fluid May Be a Better Indicator of Vitamin B6-dependent Epilepsy Than Pyridoxal 5'-Phosphate. Pediatr Neurol 2020; 113:33-41. [PMID: 32980745 DOI: 10.1016/j.pediatrneurol.2020.08.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND We aimed to demonstrate the biochemical characteristics of vitamin B6-dependent epilepsy, with a particular focus on pyridoxal 5'-phosphate and pyridoxal in the cerebrospinal fluid. METHODS Using our laboratory database, we identified patients with vitamin B6-dependent epilepsy and extracted their data on the concentrations of pyridoxal 5'-phosphate, pyridoxal, pipecolic acid, α-aminoadipic semialdehyde, and monoamine neurotransmitters. We compared the biochemical characteristics of these patients with those of other epilepsy patients with low pyridoxal 5'-phosphate concentrations. RESULTS We identified seven patients with pyridoxine-dependent epilepsy caused by an ALDH7A1 gene abnormality, two patients with pyridoxal 5'-phosphate homeostasis protein deficiency, and 28 patients with other epilepsies with low cerebrospinal fluid pyridoxal 5'-phosphate concentrations. Cerebrospinal fluid pyridoxal and pyridoxal 5'-phosphate concentrations were low in patients with vitamin B6-dependent epilepsy but cerebrospinal fluid pyridoxal concentrations were not reduced in most patients with other epilepsies with low cerebrospinal fluid pyridoxal 5'-phosphate concentrations. Increase in 3-O-methyldopa and 5-hydroxytryptophan was demonstrated in some patients with vitamin B6-dependent epilepsy, suggestive of pyridoxal 5'-phosphate deficiency in the brain. CONCLUSIONS Low cerebrospinal fluid pyridoxal concentrations may be a better indicator of pyridoxal 5'-phosphate deficiency in the brain in vitamin B6-dependent epilepsy than low cerebrospinal fluid pyridoxal 5'-phosphate concentrations. This finding is especially helpful in individuals with suspected pyridoxal 5'-phosphate homeostasis protein deficiency, which does not have known biomarkers.
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Affiliation(s)
- Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| | - Yuki Hyodo
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kosei Hasegawa
- Department of Pediatrics, Okayama University Hospital, Okayama, Japan
| | - Taikan Oboshi
- Department of Pediatric Neurology, Osaka Women's and Children's Hospital, Osaka, Japan; Department of Pediatrics, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Katsumi Imai
- Department of Pediatrics, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Naoko Ishihara
- Department of Pediatrics, Fujita Health University School of Medicine, Aichi, Japan
| | - Yuri Dowa
- Department of Neurology, Gunma Children's Medical Center, Gunma, Japan
| | - Takayoshi Koike
- Department of Pediatrics, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Toshiyuki Yamamoto
- Institute of Clinical Genomics, Tokyo Women's Medical University, Tokyo, Japan
| | - Jun Shibasaki
- Department of Neonatology, Kanagawa Children's Medical Center, Kanagawa, Japan
| | - Hiroko Shimbo
- Clinical Institute, Kanagawa Children's Medical Center, Kanagawa, Japan
| | | | - Kyoko Takano
- Center for Medical Genetics, Shinshu University Hospital, Nagano, Japan
| | - Hiroshi Shiraku
- Department of Pediatrics, JA Toride Medical Center, Ibaraki, Japan
| | - Saoko Takeshita
- Department of Pediatrics, Yokohama City University Medical Center, Kanagawa, Japan
| | - Tohru Okanishi
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Shimpei Baba
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Masaya Kubota
- Division of Neurology, National Center for Child Health and Development, Tokyo, Japan
| | - Shin-Ichiro Hamano
- Division of Neurology, Saitama Children's Medical Center, Saitama, Japan
| | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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35
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Chen PY, Tsai YW, Chang AYW, Chang HH, Hsiao YH, Huang CW, Sung PS, Chen BH, Fu TF. Increased leptin-b expression and metalloprotease expression contributed to the pyridoxine-associated toxicity in zebrafish larvae displaying seizure-like behavior. Biochem Pharmacol 2020; 182:114294. [DOI: 10.1016/j.bcp.2020.114294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/26/2022]
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36
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Saad AK, Marafi D, Mitani T, Jolly A, Du H, Elbendary HM, Jhangiani SN, Akdemir ZC, Gibbs RA, Hunter JV, Carvalho CMBC, Pehlivan D, Posey JE, Zaki MS, Lupski JR. Biallelic in-frame deletion in TRAPPC4 in a family with developmental delay and cerebellar atrophy. Brain 2020; 143:e83. [PMID: 33011761 PMCID: PMC7586085 DOI: 10.1093/brain/awaa256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Ahmed K Saad
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Department of Medical Molecular Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Dana Marafi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Department of Pediatrics, Faculty of Medicine, Kuwait University, P.O. Box 24923, 13110 Safat, Kuwait
| | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Angad Jolly
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- MD/PhD Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Haowei Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Hasnaa M Elbendary
- Department of Clinical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Zeynep C Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | | | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Jill V Hunter
- Department of Radiology, Baylor College of Medicine, Houston, Texas, 77030, USA
- E.B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston, Texas, 77030, USA
| | - Claudia M B C Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Texas Children's Hospital, Houston, Texas, 77030, USA
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Maha S Zaki
- Department of Clinical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, 77030, USA
- Texas Children's Hospital, Houston, Texas, 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, 77030, USA
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Alghamdi M, Bashiri FA, Abdelhakim M, Adly N, Jamjoom DZ, Sumaily KM, Alghanem B, Arold ST. Phenotypic and molecular spectrum of pyridoxamine-5'-phosphate oxidase deficiency: A scoping review of 87 cases of pyridoxamine-5'-phosphate oxidase deficiency. Clin Genet 2020; 99:99-110. [PMID: 32888189 PMCID: PMC7820968 DOI: 10.1111/cge.13843] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 12/29/2022]
Abstract
Pyridoxamine-5'-phosphate oxidase (PNPO) deficiency is an autosomal recessive pyridoxal 5'-phosphate (PLP)-vitamin-responsive epileptic encephalopathy. The emerging feature of PNPO deficiency is the occurrence of refractory seizures in the first year of life. Pre-maturity and fetal distress, combined with neonatal seizures, are other associated key characteristics. The phenotype results from a dependency of PLP which regulates several enzymes in the body. We present the phenotypic and genotypic spectrum of (PNPO) deficiency based on a literature review (2002-2020) of reports (n = 33) of patients with confirmed PNPO deficiency (n = 87). All patients who received PLP (n = 36) showed a clinical response, with a complete dramatic PLP response with seizure cessation observed in 61% of patients. In spite of effective seizure control with PLP, approximately 56% of patients affected with PLP-dependent epilepsy suffer developmental delay/intellectual disability. There is no diagnostic biomarker, and molecular testing required for diagnosis. However, we noted that cerebrospinal fluid (CSF) PLP was low in 81%, CSF glycine was high in 80% and urinary vanillactic acid was high in 91% of the cases. We observed only a weak correlation between the severity of PNPO protein disruption and disease outcomes, indicating the importance of other factors, including seizure onset and time of therapy initiation. We found that pre-maturity, the delay in initiation of PLP therapy and early onset of seizures correlate with a poor neurocognitive outcome. Given the amenability of PNPO to PLP therapy for seizure control, early diagnosis is essential.
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Affiliation(s)
- Malak Alghamdi
- Medical Genetics Division, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Fahad A Bashiri
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia.,Neurology division, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Marwa Abdelhakim
- Computer, Electrical and Mathematical Science and Engineering Division (CEMSE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Nouran Adly
- College of Medicine Research Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Dima Z Jamjoom
- Department of Radiology and Medical Imaging, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Khalid M Sumaily
- Clinical Biochemistry Unit, Department of Laboratory Medicine, King Saud University Medical City, King Saud University, Riyadh, Saudi Arabia
| | - Bandar Alghanem
- Medical Research Core Facility and Platforms (MRCFP), King Abdullah International Medical, Research Center/King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), King, Abdulaziz Medical City (KAMC), NGHA, Riyadh, Saudi Arabia
| | - Stefan T Arold
- Computational Bioscience, Research Center (CBRC); Division of Biological and Environmental Sciences and Engineering, (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
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38
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Pavitt S, Sandoval Karamian AG, Chattree G, Klotz J, Beres S. Teaching Video NeuroImages: Atypical Abnormal Eye Movements in PNPO-Related Epilepsy. Neurology 2020; 96:e1927. [PMID: 32913027 DOI: 10.1212/wnl.0000000000010861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Sara Pavitt
- From Stanford Children's Health (S.P., A.G.S.K., J.K., S.B.) and Stanford Health Care (G.C.), Palo Alto, CA.
| | - Amanda G Sandoval Karamian
- From Stanford Children's Health (S.P., A.G.S.K., J.K., S.B.) and Stanford Health Care (G.C.), Palo Alto, CA
| | - Gaurav Chattree
- From Stanford Children's Health (S.P., A.G.S.K., J.K., S.B.) and Stanford Health Care (G.C.), Palo Alto, CA
| | - Jenna Klotz
- From Stanford Children's Health (S.P., A.G.S.K., J.K., S.B.) and Stanford Health Care (G.C.), Palo Alto, CA
| | - Shannon Beres
- From Stanford Children's Health (S.P., A.G.S.K., J.K., S.B.) and Stanford Health Care (G.C.), Palo Alto, CA
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39
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Brennenstuhl H, Garbade SF, Okun JG, Feyh P, Hoffmann GF, Langhans CD, Opladen T. Semi-quantitative detection of a vanillactic acid/vanillylmandelic acid ratio in urine is a reliable diagnostic marker for aromatic L-amino acid decarboxylase deficiency. Mol Genet Metab 2020; 131:163-170. [PMID: 32675002 DOI: 10.1016/j.ymgme.2020.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND Aromatic L-amino acid decarboxylase (AADC) deficiency is a primary neurotransmitter defect of the biosynthesis of catecholamines and serotonin. The phenotype consists of varying degrees of neurological impairment, including motor and non-motor symptoms. Treatment outcomes correlate with the time point of diagnosis and treatment initiation; therefore, reliable diagnostic markers are necessary. Increased vanillactic acid (VLA) concentrations in the analysis of organic acids in urine have been reported in AADC deficiency. However, this elevation is often subtle and easily missed. In this study, we evaluate the semi-quantitative determination of VLA and vanillylmandelic acid (VMA) concentrations and establish the ratio of a VLA/VMA as a novel diagnostic marker for AADC deficiency. METHODS Urine samples obtained from 10,095 non-AADC deficient controls and 14 confirmed AADC deficient patients were used for organic acid analysis by liquid-liquid extraction of the acidified samples and gas chromatographic-mass spectrometric separation after trimethylsilylation. The semi-quantitative determination of VLA and VMA concentrations and the calculation of a VLA/VMA ratio were evaluated as a diagnostic marker for AADC deficiency. RESULTS The mean VLA and VMA concentrations in 10,095 non-AADCD samples was 0.3 mmol/mol creatinine (SD = 1.18, range 0-57.79) and 5.59 mmol/mol creatinine (SD = 3.87, range 0.04-60.62), respectively. The mean concentration of VLA in 14 patient-derived samples was 10.24 mmol/mol creatinine, (SD = 11.58, range = 0.37-33.06) and 0.45 mmol/mol creatinine for VMA (SD = 0.29, range 0.11-1.27). The mean VLA/VMA ratio in non-AADC controls was 0.07 (SD = 0.37, range 0.0-23.24), whereas AADC deficient patients revealed a mean VLA/VMA ratio of 23.16 (SD = 22.83, range 0.97-74.1). The VLA/VMA ratio thus allows a reliable identification of patients with AADC deficiency, especially in the young age cohort as it decreases with age. To take this into account, age-adjusted thresholds have been developed. CONCLUSION Determination of individual concentrations of VLA and VMA in urine does not allow a reliable diagnosis of AADC deficiency. In this study, we could demonstrate that a semi-quantitative analysis of organic acids in urine allows the formation of metabolite ratios and that the VLA/VMA ratio is a reliable, easily accessible, new parameter for the diagnosis of AADC deficiency.
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Affiliation(s)
- Heiko Brennenstuhl
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Sven F Garbade
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Jürgen G Okun
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Patrik Feyh
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Georg F Hoffmann
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Claus-Dieter Langhans
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Thomas Opladen
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany.
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40
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Barile A, Nogués I, di Salvo ML, Bunik V, Contestabile R, Tramonti A. Molecular characterization of pyridoxine 5'-phosphate oxidase and its pathogenic forms associated with neonatal epileptic encephalopathy. Sci Rep 2020; 10:13621. [PMID: 32788630 PMCID: PMC7424515 DOI: 10.1038/s41598-020-70598-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/31/2020] [Indexed: 01/18/2023] Open
Abstract
Defects of vitamin B6 metabolism are responsible for severe neurological disorders, such as pyridoxamine 5'-phosphate oxidase deficiency (PNPOD; OMIM: 610090), an autosomal recessive inborn error of metabolism that usually manifests with neonatal-onset severe seizures and subsequent encephalopathy. At present, 27 pathogenic mutations of the gene encoding human PNPO are known, 13 of which are homozygous missense mutations; however, only 3 of them have been characterised with respect to the molecular and functional properties of the variant enzyme forms. Moreover, studies on wild type and variant human PNPOs have so far largely ignored the regulation properties of this enzyme. Here, we present a detailed characterisation of the inhibition mechanism of PNPO by pyridoxal 5'-phosphate (PLP), the reaction product of the enzyme. Our study reveals that human PNPO has an allosteric PLP binding site that plays a crucial role in the enzyme regulation and therefore in the regulation of vitamin B6 metabolism in humans. Furthermore, we have produced, recombinantly expressed and characterised several PNPO pathogenic variants responsible for PNPOD (G118R, R141C, R225H, R116Q/R225H, and X262Q). Such replacements mainly affect the catalytic activity of PNPO and binding of the enzyme substrate and FMN cofactor, leaving the allosteric properties unaltered.
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Affiliation(s)
- Anna Barile
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy.,Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Isabel Nogués
- Istituto di Ricerca sugli Ecosistemi Terrestri, Consiglio Nazionale delle Ricerche, 00015, Monterotondo, Rome, Italy
| | - Martino L di Salvo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Victoria Bunik
- Belozersky Institute of Physico-Chemical Biology, Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia.,Department of Biochemistry, Sechenov University, Trubetskaya, 8/2, Moscow, 119991, Russia
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy.
| | - Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy. .,Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy.
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41
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Gowda VK, Vegda H, Nagarajan BB, Shivappa SK. Clinical Profile and Outcome of Indian Children with Aromatic L-Amino Acid Decarboxylase Deficiency: A primary CSF Neurotransmitter Disorder Mimicking as Dyskinetic Cerebral Palsy. J Pediatr Genet 2020; 10:85-91. [PMID: 33996177 DOI: 10.1055/s-0040-1714690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/09/2020] [Indexed: 10/23/2022]
Abstract
Aromatic L-amino acid decarboxylase (AADC) deficiency is a disorder of neurotransmitter synthesis. It presents with psychomotor delay, dystonia, oculogyric crisis, and autonomic features. There is paucity of literature on this disorder. Hence, we are reporting this series with an objective to study profile and outcome of Indian children with AADC deficiency. In this retrospective review, all case records of genetically confirmed cases of AADC deficiency at the pediatric neurology department in a tertiary care hospital, from March 2014 to March 2020, were analyzed. The data were extracted in a predesigned proforma and analyzed. Out of seven cases, five were males. Median age of onset of symptoms was 4 months but median age of diagnosis was 12 months. All of them had developmental delay, oculogyric crisis, dystonia, increased sweating, intermittent fever, feeding and sleep disturbance, irritability, failure to thrive, axial hypotonia with dyskinetic quadriparesis, and normal magnetic resonance imaging (MRI) of brain and electroencephalogram (EEG). All of them were treated with pyridoxal 5-phosphate, trihexyphenidyl and pramipexole and six cases, in addition, were given bromocriptine. One case was additionally treated with selegiline. One case showed good improvement, five showed partial improvement, and one case expired. In conclusion, AADC deficiency should be suspected in any child with dyskinetic quadriparesis, oculogyric crisis, autonomic disturbances like increased sweating, intermittent fever, and sleep disturbance with normal neuroimaging.
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Affiliation(s)
- Vykuntaraju K Gowda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Hemadri Vegda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Balamurugan B Nagarajan
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Sanjay K Shivappa
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
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42
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Keller N, Mendoza-Ferreira N, Maroofian R, Chelban V, Khalil Y, Mills PB, Boostani R, Torbati PN, Karimiani EG, Thiele H, Houlden H, Wirth B, Karakaya M. Hereditary polyneuropathy with optic atrophy due to PDXK variant leading to impaired Vitamin B6 metabolism. Neuromuscul Disord 2020; 30:583-589. [DOI: 10.1016/j.nmd.2020.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/07/2020] [Accepted: 04/21/2020] [Indexed: 01/13/2023]
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43
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Akiyama T, Toda S, Kimura N, Mogami Y, Hanaoka Y, Tokorodani C, Ito T, Miyahara H, Hyodo Y, Kobayashi K. Vitamin B6 in acute encephalopathy with biphasic seizures and late reduced diffusion. Brain Dev 2020; 42:402-407. [PMID: 32107100 DOI: 10.1016/j.braindev.2020.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/27/2020] [Accepted: 02/12/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND The initial presentation of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is indistinguishable from that of complex febrile seizures (FS), which poses a great diagnostic challenge for clinicians. Excitotoxicity is speculated to be the pathogenesis of AESD. Vitamin B6 (VB6) is essential for the biosynthesis of gamma-aminobutyric acid, an inhibitory neurotransmitter. The aim of this study is to investigate our hypothesis that VB6 deficiency in the brain may play a role in AESD. METHODS We obtained cerebrospinal fluid (CSF) samples from pediatric patients with AESD after early seizures and those with FS. We measured pyridoxal 5'-phosphate (PLP) and pyridoxal (PL) concentrations in the CSF samples using high-performance liquid chromatography with fluorescence detection. RESULTS The subjects were 5 patients with AESD and 17 patients with FS. Age did not differ significantly between AESD and FS. In AESD, CSF PLP concentration was marginally lower (p = 0.0999) and the PLP-to-PL ratio was significantly (p = 0.0417) reduced compared to those in FS. CONCLUSIONS Although it is impossible to conclude that low PLP concentration and PLP-to-PL ratio are causative of AESD, this may be a risk factor for developing AESD. When combined with other markers, this finding may be useful in distinguishing AESD from FS upon initial presentation.
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Affiliation(s)
- Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| | - Soichiro Toda
- Department of Pediatrics, Kameda Medical Center, Chiba, Japan
| | - Nobusuke Kimura
- Department of Pediatrics, Japanese Red Cross Otsu Hospital, Shiga, Japan
| | - Yukiko Mogami
- Department of Pediatric Neurology, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Yoshiyuki Hanaoka
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan
| | - Chiho Tokorodani
- Department of Pediatrics, Kochi Health Sciences Center, Kochi, Japan
| | - Tomoshiro Ito
- Department of Pediatrics, Sapporo City General Hospital, Hokkaido, Japan
| | - Hiroyuki Miyahara
- Department of Pediatrics, Kurashiki Central Hospital, Okayama, Japan
| | - Yuki Hyodo
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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Brennenstuhl H, Kohlmüller D, Gramer G, Garbade SF, Syrbe S, Feyh P, Kölker S, Okun JG, Hoffmann GF, Opladen T. High throughput newborn screening for aromatic ʟ-amino-acid decarboxylase deficiency by analysis of concentrations of 3-O-methyldopa from dried blood spots. J Inherit Metab Dis 2020; 43:602-610. [PMID: 31849064 DOI: 10.1002/jimd.12208] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/12/2019] [Accepted: 12/16/2019] [Indexed: 11/06/2022]
Abstract
Aromatic l-amino-acid decarboxylase (AADC) deficiency is an inherited disorder of biogenic amine metabolism with a broad neurological phenotype. The clinical symptoms overlap with other diseases resulting in an often delayed diagnosis. Innovative disease-changing treatment options, particularly gene therapy, have emphasised the need for an early diagnosis. We describe the first method for 3-O-methyldopa (3-OMD) analysis in dried blood spots (DBS) suitable for high throughput newborn screening (NBS). We established a novel tandem mass spectrometry method to quantify 3-OMD in DBS and successfully tested it in 38 888 unaffected newborns, 14 heterozygous DDC variant carriers, seven known AADC deficient patients, and 1079 healthy control subjects. 3-OMD concentrations in 38 888 healthy newborns revealed a mean of 1.16 μmol/L (SD = 0.31, range 0.31-4.6 μmol/L). 1079 non-AADC control subjects (0-18 years) showed a mean 3-OMD concentration of 0.78 μmol/L (SD = 1.75, range 0.24-2.36 μmol/L) with a negative correlation with age. Inter- and intra-assay variability was low, and 3-OMD was stable over 32 days under different storage conditions. We identified seven confirmed AADC deficient patients (mean 3-OMD 9.88 μmol/L [SD = 13.42, range 1.82-36.93 μmol/L]). The highest concentration of 3-OMD was found in a NBS filter card of a confirmed AADC deficient patient with a mean 3-OMD of 35.95 μmol/L. 14 DDC variant carriers showed normal 3-OMD concentrations. We demonstrate a novel high-throughput method to measure 3-OMD in DBS, which allows integration in existing NBS programs enabling early diagnosis of AADC deficiency.
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Affiliation(s)
- Heiko Brennenstuhl
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Dirk Kohlmüller
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Gwendolyn Gramer
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Sven F Garbade
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Steffen Syrbe
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Patrik Feyh
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Stefan Kölker
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Jürgen G Okun
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Georg F Hoffmann
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
| | - Thomas Opladen
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital, Heidelberg, Germany
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45
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Contestabile R, di Salvo ML, Bunik V, Tramonti A, Vernì F. The multifaceted role of vitamin B 6 in cancer: Drosophila as a model system to investigate DNA damage. Open Biol 2020; 10:200034. [PMID: 32208818 PMCID: PMC7125957 DOI: 10.1098/rsob.200034] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A perturbed uptake of micronutrients, such as minerals and vitamins, impacts on different human diseases, including cancer and neurological disorders. Several data converge towards a crucial role played by many micronutrients in genome integrity maintenance and in the establishment of a correct DNA methylation pattern. Failure in the proper accomplishment of these processes accelerates senescence and increases the risk of developing cancer, by promoting the formation of chromosome aberrations and deregulating the expression of oncogenes. Here, the main recent evidence regarding the impact of some B vitamins on DNA damage and cancer is summarized, providing an integrated and updated analysis, mainly centred on vitamin B6. In many cases, it is difficult to finely predict the optimal vitamin rate that is able to protect against DNA damage, as this can be influenced by a given individual's genotype. For this purpose, a precious resort is represented by model organisms which allow limitations imposed by more complex systems to be overcome. In this review, we show that Drosophila can be a useful model to deeply understand mechanisms underlying the relationship between vitamin B6 and genome integrity.
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Affiliation(s)
- Roberto Contestabile
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, P.le A. Moro, 5, 00185, Roma, Italy
| | - Martino Luigi di Salvo
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, P.le A. Moro, 5, 00185, Roma, Italy
| | - Victoria Bunik
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia.,Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119991, Russia.,Sechenov Medical University, Sechenov University, 119048 Moscow, Russia
| | - Angela Tramonti
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, P.le A. Moro, 5, 00185, Roma, Italy.,Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Pl.e A. Moro, 5, 00185 Roma, Italy
| | - Fiammetta Vernì
- Dipartimento di Biologia e Biotecnologie 'Charles Darwin', Sapienza Università di Roma, Pl.e A. Moro, 5, 00185 Roma, Italy
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46
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Abstract
Developmental and epileptic encephalopathies (DEEs) can be primarily attributed to genetic causes. The genetic landscape of DEEs has been largely shaped by the rise of high-throughput sequencing, which led to the discovery of new DEE-associated genes and helped identify de novo pathogenic variants. We discuss briefly the contribution of de novo variants to DEE and also focus on alternative inheritance models that contribute to DEE. First, autosomal recessive inheritance in outbred populations may have a larger contribution than previously appreciated, accounting for up to 13% of DEEs. A small subset of genes that typically harbor de novo variants have been associated with recessive inheritance, and often these individuals have more severe clinical presentations. Additionally, pathogenic variants in X-linked genes have been identified in both affected males and females, possibly due to a lack of X-chromosome inactivation skewing. Collectively, exome sequencing has resulted in a molecular diagnosis for many individuals with DEE, but this still leaves many cases unsolved. Multiple factors contribute to the missing etiology, including nonexonic variants, mosaicism, epigenetics, and oligogenic inheritance. Here, we focus on the first 2 factors. We discuss the promises and challenges of genome sequencing, which allows for a more comprehensive analysis of the genome, including interpretation of structural and noncoding variants and also yields a high number of de novo variants for interpretation. We also consider the contribution of genetic mosaicism, both what it means for a molecular diagnosis in mosaic individuals and the important implications for genetic counseling.
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Affiliation(s)
- Hannah C Happ
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Gemma L Carvill
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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47
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Chi W, Iyengar ASR, Albersen M, Bosma M, Verhoeven-Duif NM, Wu CF, Zhuang X. Pyridox (am) ine 5'-phosphate oxidase deficiency induces seizures in Drosophila melanogaster. Hum Mol Genet 2020; 28:3126-3136. [PMID: 31261385 DOI: 10.1093/hmg/ddz143] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/12/2022] Open
Abstract
Pyridox (am) ine 5'-phosphate oxidase (PNPO) is a rate-limiting enzyme in converting dietary vitamin B6 (VB6) to pyridoxal 5'-phosphate (PLP), the biologically active form of VB6 and involved in the synthesis of neurotransmitters including γ-aminobutyric acid (GABA), dopamine, and serotonin. In humans, PNPO mutations have been increasingly identified in neonatal epileptic encephalopathy and more recently also in early-onset epilepsy. Till now, little is known about the neurobiological mechanisms underlying PNPO-deficiency-induced seizures due to the lack of animal models. Previously, we identified a c.95 C>A missense mutation in sugarlethal (sgll)-the Drosophila homolog of human PNPO (hPNPO)-and found mutant (sgll95) flies exhibiting a lethal phenotype on a diet devoid of VB6. Here, we report the establishment of both sgll95 and ubiquitous sgll knockdown (KD) flies as valid animal models of PNPO-deficiency-induced epilepsy. Both sgll95 and sgll KD flies exhibit spontaneous seizures before they die. Electrophysiological recordings reveal that seizures caused by PNPO deficiency have characteristics similar to that in flies treated with the GABA antagonist picrotoxin. Both seizures and lethality are associated with low PLP levels and can be rescued by ubiquitous expression of wild-type sgll or hPNPO, suggesting the functional conservation of the PNPO enzyme between humans and flies. Results from cell type-specific sgll KD further demonstrate that PNPO in the brain is necessary for seizure prevention and survival. Our establishment of the first animal model of PNPO deficiency will lead to better understanding of VB6 biology, the PNPO gene and its mutations discovered in patients, and can be a cost-effective system to test therapeutic strategies.
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Affiliation(s)
- Wanhao Chi
- Committee on Genetics, Genomics and Systems Biology.,Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Atulya S R Iyengar
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Monique Albersen
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Marjolein Bosma
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Nanda M Verhoeven-Duif
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Chun-Fang Wu
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
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48
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Cárdenas-Rodríguez N, Carmona-Aparicio L, Pérez-Lozano DL, Ortega-Cuellar D, Gómez-Manzo S, Ignacio-Mejía I. Genetic variations associated with pharmacoresistant epilepsy (Review). Mol Med Rep 2020; 21:1685-1701. [PMID: 32319641 PMCID: PMC7057824 DOI: 10.3892/mmr.2020.10999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is a common, serious neurological disorder worldwide. Although this disease can be successfully treated in most cases, not all patients respond favorably to medical treatments, which can lead to pharmacoresistant epilepsy. Drug-resistant epilepsy can be caused by a number of mechanisms that may involve environmental and genetic factors, as well as disease- and drug-related factors. In recent years, numerous studies have demonstrated that genetic variation is involved in the drug resistance of epilepsy, especially genetic variations found in drug resistance-related genes, including the voltage-dependent sodium and potassium channels genes, and the metabolizer of endogenous and xenobiotic substances genes. The present review aimed to highlight the genetic variants that are involved in the regulation of drug resistance in epilepsy; a comprehensive understanding of the role of genetic variation in drug resistance will help us develop improved strategies to regulate drug resistance efficiently and determine the pathophysiological processes that underlie this common human neurological disease.
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Affiliation(s)
- Noemí Cárdenas-Rodríguez
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Liliana Carmona-Aparicio
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Diana L Pérez-Lozano
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Daniel Ortega-Cuellar
- Laboratory of Experimental Nutrition, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Saúl Gómez-Manzo
- Laboratory of Genetic Biochemistry, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Iván Ignacio-Mejía
- Laboratory of Translational Medicine, Military School of Health Graduates, Lomas de Sotelo, Militar, Mexico City 11200, Mexico
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49
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Helbig I, Ellis CA. Personalized medicine in genetic epilepsies - possibilities, challenges, and new frontiers. Neuropharmacology 2020; 172:107970. [PMID: 32413583 DOI: 10.1016/j.neuropharm.2020.107970] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 01/05/2020] [Accepted: 01/16/2020] [Indexed: 12/13/2022]
Abstract
Identifying the optimal treatment based on specific characteristics of each patient is the main promise of precision medicine. In the field of epilepsy, the identification of more than 100 causative genes provides the enticing possibility of treatments targeted to specific disease etiologies. These conditions include classical examples, such as the use of vitamin B6 in antiquitin deficiency or the ketogenic diet in GLUT1 deficiency, where the disease mechanism can be directly addressed by the selection of a specific therapeutic compound. For epilepsies caused by channelopathies there have been advances in understanding how the selection of existing medications can be targeted to the functional consequences of genetic alterations. We discuss the examples of the use of sodium channel blockers such as phenytoin and oxcarbazepine in the sodium channelopathies, quinidine in KCNT1-related epilepsies, and strategies in GRIN-related epilepsies as examples of epilepsy precision medicine. Assessing the clinical response to targeted treatments of these conditions has been complicated by genetic and phenotypic heterogeneity, as well as by various neurological and non-neurological comorbidities. Moving forward, the development of standardized outcome measures will be critical to successful precision medicine trials in complex and heterogeneous disorders like the epilepsies. Finally, we address new frontiers in epilepsy precision medicine, including the need to match the growing volume of genetic data with high-throughput functional assays to assess the functional consequences of genetic variants and the ability to extract clinical data at large scale from electronic medical records and apply quantitative methods based on standardized phenotyping language.
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Affiliation(s)
- Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA.
| | - Colin A Ellis
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
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50
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Johnstone DL, Al-Shekaili HH, Tarailo-Graovac M, Wolf NI, Ivy AS, Demarest S, Roussel Y, Ciapaite J, van Roermund CWT, Kernohan KD, Kosuta C, Ban K, Ito Y, McBride S, Al-Thihli K, Abdelrahim RA, Koul R, Al Futaisi A, Haaxma CA, Olson H, Sigurdardottir LY, Arnold GL, Gerkes EH, Boon M, Heiner-Fokkema MR, Noble S, Bosma M, Jans J, Koolen DA, Kamsteeg EJ, Drögemöller B, Ross CJ, Majewski J, Cho MT, Begtrup A, Wasserman WW, Bui T, Brimble E, Violante S, Houten SM, Wevers RA, van Faassen M, Kema IP, Lepage N, Lines MA, Dyment DA, Wanders RJA, Verhoeven-Duif N, Ekker M, Boycott KM, Friedman JM, Pena IA, van Karnebeek CDM. PLPHP deficiency: clinical, genetic, biochemical, and mechanistic insights. Brain 2020; 142:542-559. [PMID: 30668673 DOI: 10.1093/brain/awy346] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/30/2018] [Accepted: 11/13/2018] [Indexed: 12/20/2022] Open
Abstract
Biallelic pathogenic variants in PLPBP (formerly called PROSC) have recently been shown to cause a novel form of vitamin B6-dependent epilepsy, the pathophysiological basis of which is poorly understood. When left untreated, the disease can progress to status epilepticus and death in infancy. Here we present 12 previously undescribed patients and six novel pathogenic variants in PLPBP. Suspected clinical diagnoses prior to identification of PLPBP variants included mitochondrial encephalopathy (two patients), folinic acid-responsive epilepsy (one patient) and a movement disorder compatible with AADC deficiency (one patient). The encoded protein, PLPHP is believed to be crucial for B6 homeostasis. We modelled the pathogenicity of the variants and developed a clinical severity scoring system. The most severe phenotypes were associated with variants leading to loss of function of PLPBP or significantly affecting protein stability/PLP-binding. To explore the pathophysiology of this disease further, we developed the first zebrafish model of PLPHP deficiency using CRISPR/Cas9. Our model recapitulates the disease, with plpbp-/- larvae showing behavioural, biochemical, and electrophysiological signs of seizure activity by 10 days post-fertilization and early death by 16 days post-fertilization. Treatment with pyridoxine significantly improved the epileptic phenotype and extended lifespan in plpbp-/- animals. Larvae had disruptions in amino acid metabolism as well as GABA and catecholamine biosynthesis, indicating impairment of PLP-dependent enzymatic activities. Using mass spectrometry, we observed significant B6 vitamer level changes in plpbp-/- zebrafish, patient fibroblasts and PLPHP-deficient HEK293 cells. Additional studies in human cells and yeast provide the first empirical evidence that PLPHP is localized in mitochondria and may play a role in mitochondrial metabolism. These models provide new insights into disease mechanisms and can serve as a platform for drug discovery.
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Affiliation(s)
- Devon L Johnstone
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Hilal H Al-Shekaili
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Maja Tarailo-Graovac
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Institute of Physiology and Biochemistry, Faculty of Biology, The University of Belgrade, Belgrade, Serbia.,Departments of Biochemistry, Molecular Biology, and Medical Genetics, Cumming School of Medicine, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam University Medical Centres, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Autumn S Ivy
- Division of Child Neurology, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, CA, USA
| | - Scott Demarest
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine, Children's Hospital Colorado, CO, USA
| | - Yann Roussel
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Jolita Ciapaite
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands
| | - Carlo W T van Roermund
- Department of Pediatrics and Clinical Chemistry, Laboratory Division, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Ceres Kosuta
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kevin Ban
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Yoko Ito
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Skye McBride
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Khalid Al-Thihli
- Genetic and Developmental Medicine Clinic, Sultan Qaboos University Hospital, Muscat, Oman
| | - Rana A Abdelrahim
- Department of Child Health, Sultan Qaboos University Hospital, Muscat, Oman
| | - Roshan Koul
- Paediatric Neurology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Amna Al Futaisi
- Paediatric Neurology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Charlotte A Haaxma
- Department of Pediatric Neurology, Amalia Children's Hospital and Donders Institute of Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Heather Olson
- Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA
| | - Laufey Yr Sigurdardottir
- Department of Neurology, University of Central Florida, Nemours Children's Hospital, Orlando, FL, USA
| | - Georgianne L Arnold
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburg, PA, USA
| | - Erica H Gerkes
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Boon
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Sandra Noble
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands
| | - Judith Jans
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - David A Koolen
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Britt Drögemöller
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Colin J Ross
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jacek Majewski
- McGill University and Genome Quebec Innovation Centre, Montreal, QC, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada
| | | | | | - Wyeth W Wasserman
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Tuan Bui
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Elise Brimble
- Department of Neurology and Neurological Sciences, Stanford Medicine, Stanford, CA, USA
| | - Sara Violante
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sander M Houten
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ron A Wevers
- United for Metabolic Diseases, The Netherlands.,Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Martijn van Faassen
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ido P Kema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nathalie Lepage
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | | | - Matthew A Lines
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - David A Dyment
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Medical Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Ronald J A Wanders
- Department of Pediatrics and Clinical Chemistry, Laboratory Division, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centres, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Nanda Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Marc Ekker
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Medical Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Izabella A Pena
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Clara D M van Karnebeek
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,United for Metabolic Diseases, The Netherlands.,Departments of Pediatrics and Clinical Genetics, Amsterdam University Medical Centres, Amsterdam, The Netherlands.,Centre for Molecular Medicine and Therapeutics, Department of Pediatrics, University of British Columbia, Vancouver, Canada
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