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Falsaperla R, Sciacca M, Collotta AD, Tardino LG, Marino S, Marino SD, Privitera GF, Vitaliti G, Ruggieri M. PYRIDOXINE-dependent epilepsy (PDE): An observational study of neonatal cases on the role of pyridoxine in patients treated with standard anti-seizure medications. Seizure 2024; 118:156-163. [PMID: 38735085 DOI: 10.1016/j.seizure.2024.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 05/14/2024] Open
Abstract
BACKGROUND The main objective of this study was to evaluate the neurological consequences of delayed pyridoxine administration in patients diagnosed with Pyridoxin Dependent Epilepsies (PDE). MATERIALS AND METHODS We reviewed 29 articles, comprising 52 genetically diagnosed PDE cases, ensuring data homogeneity. Three additional cases were included from the General Pediatric Operative Unit of San Marco Hospital. Data collection considered factors like age at the first seizure's onset, EEG reports, genetic analyses, and more. Based on the response to first-line antiseizure medications, patients were categorized into four distinct groups. Follow-up evaluations employed various scales to ascertain neurological, cognitive, and psychomotor developments. RESULTS Our study includes 55 patients (28 males and 27 females), among whom 15 were excluded for the lack of follow-up data. 21 patients were categorized as "Responder with Relapse", 11 as "Resistant", 6 as "Pyridoxine First Approach", and 2 as "Responders". The neurological outcome revealed 37,5 % with no neurological effects, 37,5 % showed complications in two developmental areas, 15 % in one, and 10 % in all areas. The statistical analysis highlighted a positive correlation between the time elapsed from the administration of pyridoxine after the first seizure and worse neurological outcomes. On the other hand, a significant association was found between an extended latency period (that is, the time that elapsed between the onset of the first seizure and its recurrence) and worse neurological outcomes in patients who received an unfavorable score on the neurological evaluation noted in a subsequent follow-up. CONCLUSIONS The study highlights the importance of early recognition and intervention in PDE. Existing medical protocols frequently overlook the timely diagnosis of PDE. Immediate administration of pyridoxine, guided by a swift diagnosis in the presence of typical symptoms, might improve long-term neurological outcomes, and further studies should evaluate the outcome of PDE neonates promptly treated with Pyridoxine.
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Affiliation(s)
- Raffaele Falsaperla
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy; Unit of Neonatal Intensive Care and Neonatology, Policlinico "G. Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy.
| | - Monica Sciacca
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy
| | - Ausilia Desiree Collotta
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy
| | - Lucia Giovanna Tardino
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy
| | - Silvia Marino
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy
| | - Simona Domenica Marino
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy
| | - Greta Francesca Privitera
- Bioinformatics Unit, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Giovanna Vitaliti
- General Pediatrics and Pediatric Emergency Department, "Policlinico G.Rodolico-San Marco" University Hospital, University of Catania, 95100 Catania, Italy.
| | - Martino Ruggieri
- Department of Child and Experimental Medicine, Section of Paediatrics and Child Neuropsychiatry, University of Catania, Italy
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2
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Shen JJ, Wortmann SB, de Boer L, Kluijtmans LAJ, Huigen MCDG, Koch J, Ross S, Collins CD, van der Lee R, van Karnebeek CDM, Hegde MR. The role of clinical response to treatment in determining pathogenicity of genomic variants. Genet Med 2020; 23:581-585. [PMID: 33087887 DOI: 10.1038/s41436-020-00996-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
PURPOSE The 2015 American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines for the interpretation of sequence variants provide a framework to standardize terminology in the classification of variants uncovered through genetic testing. We aimed to assess the validity of utilizing clinical response to therapies specifically targeted to a suspected disease in clarifying variant pathogenicity. METHODS Five families with disparate clinical presentations and different genetic diseases evaluated and treated in multiple diagnostic settings are summarized. RESULTS Extended evaluations indicated possible genetic diagnoses and assigned candidate causal variants, but the cumulative clinical, biochemical, and molecular information in each instance was not completely consistent with the identified disease. Initiation of treatment specific to the suspected diagnoses in the affected individuals led to clinical improvement in all five families. CONCLUSION We propose that the effect of therapies that are specific and targeted to treatable genetic diseases embodies an in vivo physiological response and could be considered as additional criteria within the 2015 ACMG/AMP guidelines in determining genomic variant pathogenicity.
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Affiliation(s)
- Joseph J Shen
- Division of Genetics, Department of Pediatrics, UCSF Fresno, Fresno, CA, USA.
| | - Saskia B Wortmann
- University Children's Hospital, PMU Salzburg, Salzburg, Austria.,Radboud Centre for Mitochondrial Medicine, Department of Paediatrics, Amalia Children's Hospital, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Lonneke de Boer
- Radboud Centre for Mitochondrial Medicine, Department of Paediatrics, Amalia Children's Hospital, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Leo A J Kluijtmans
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Marleen C D G Huigen
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Johannes Koch
- University Children's Hospital, PMU Salzburg, Salzburg, Austria
| | | | | | - Robin van der Lee
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Clara D M van Karnebeek
- Radboud Centre for Mitochondrial Medicine, Department of Paediatrics, Amalia Children's Hospital, Radboud University Medical Centre, Nijmegen, The Netherlands.,Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,Department of Pediatrics, Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Paediatrics, Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Madhuri R Hegde
- PerkinElmer Genomics, Duluth, GA, USA.,Department of Applied Biology, Georgia Institute of Technology, Atlanta, GA, USA
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3
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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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4
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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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5
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Mohanlal S, Bindu PS, Sureshbabu S, Kumar S. Variable treatment response in a patient with pyridoxal N phosphate oxidase (PNPO) deficiency- understanding the paradox. Epilepsy Behav Rep 2020; 14:100357. [PMID: 32395712 PMCID: PMC7210397 DOI: 10.1016/j.ebr.2020.100357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/07/2020] [Accepted: 02/29/2020] [Indexed: 11/21/2022] Open
Abstract
A 6-year-old girl presented with history of infantile onset epileptic encephalopathy and developmental delay. She had polymorphic seizures that were refractory to regular anti-seizure medication. Incomplete control of seizures was achieved on starting pyridoxine, riboflavin and thiamine. Clinical exome sequencing done at 4 years revealed PNPO deficiency with a homozygous mutation in the highly conserved exon 3:c.352G > A p.Gly118R region of the gene. Thereafter, pyridoxine was weaned and pyridoxal phosphate was added with resultant refractory status epilepticus, which necessitated our approach to start pyridoxine and stop pyridoxal phosphate. With two antiseizure medication and three vitamins, she had improved seizure control. At 6 years of age an attempt to wean off riboflavin resulted in break through seizures. After restarting riboflavin along with pyridoxal phosphate, pyridoxine in low doses and two antiseizure medications, the child achieved good seizure control. Though partial responsiveness to pyridoxine with gene mutation in the exon 3: c.352G > A p. Gly118R is known, riboflavin dependence and transient worsening of seizures off pyridoxine has not been described to our knowledge. Our case highlights the importance of identifying the precise gene mutationsequence to properly identify variants relative to individual phenotypic expression, treatment responsivness and need for added vitamin supplementation. PNPO (pyridoxal N phosphate oxidase) deficiency is a treatable cause of infantile and neonatal onset epileptic encephalopathy PNPO deficiency is classically responsive to pyridoxal phosphate but other agents like high dose pyridoxine and riboflavin are also useful depending upon the genetic mutation involved. The present report describes a paradoxical worsening which occurred when switched from pyridoxine to pyridoxal phosphate.
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Affiliation(s)
- Smilu Mohanlal
- Department of Neurology and Paediatric Neurosciences, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India
| | - Parayil Sankaran Bindu
- Mito-Foundation Clinical Fellow, Genetic metabolic disorders service children's hospital, Westmead, NSW, Australia
| | - Sachin Sureshbabu
- Department of Neurology and Paediatric Neurosciences, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India
| | - Suresh Kumar
- Department of Paediatrics, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India
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6
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Abstract
Seizures are the most acute evident manifestation of central nervous system dysfunction in neonates. The incidence is higher in very low weight neonates, about 58/100 live births, as opposed to full-term infants, estimated about 3.5/100 live births. Neonatal seizures represent the clinical manifestation of a non-specific disorder of cortical cerebral dysfunction, which could lead to permanent brain injury. The etiology is multifactorial and requires a judicious assessment of each clinical scenario. The diagnosis and its management are further complicated as most neonatal seizures may have very subtle or no clinical changes and the diagnosis may be just based on EEG findings, so-called subclinical. The treatment is dependent on the etiology, but early and opportune intervention can prevent further brain damage and improve prognosis. Although early identification and treatment are essential, the diagnosis of neonatal seizures can be further complicated by the clinical presentations, possible etiologies, and treatments. Nevertheless, research studies and clinical evidence have shown that early treatment with anti-seizure medications can change the outcome.
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Affiliation(s)
- Edgar Andrade
- Pediatric Neurology, Institute of Pediatric Neurosciences of Florida, Ocala, USA
| | | | - Zakir I Shaikh
- Pediatrics, Surat Municipal Institute of Medical Education and Research, Surat, IND
| | - Alcy R Torres
- Pediatrics, Boston University School of Medicine, Boston, USA
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7
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Boylan GB, Kharoshankaya L, Mathieson SR. Diagnosis of seizures and encephalopathy using conventional EEG and amplitude integrated EEG. HANDBOOK OF CLINICAL NEUROLOGY 2019; 162:363-400. [PMID: 31324321 DOI: 10.1016/b978-0-444-64029-1.00018-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Seizures are more common in the neonatal period than at any other time of life, partly due to the relative hyperexcitability of the neonatal brain. Brain monitoring of sick neonates in the NICU using either conventional electroencephalography or amplitude integrated EEG is essential to accurately detect seizures. Treatment of seizures is important, as evidence increasingly indicates that seizures damage the brain in addition to that caused by the underlying etiology. Prompt treatment has been shown to reduce seizure burden with the potential to ameliorate seizure-mediated damage. Neonatal encephalopathy most commonly caused by a hypoxia-ischemia results in an alteration of mental status and problems such as seizures, hypotonia, apnea, and feeding difficulties. Confirmation of encephalopathy with EEG monitoring can act as an important adjunct to other investigations and the clinical examination, particularly when considering treatment strategies such as therapeutic hypothermia. Brain monitoring also provides useful early prognostic indicators to clinicians. Recent use of machine learning in algorithms to continuously monitor the neonatal EEG, detect seizures, and grade encephalopathy offers the exciting prospect of real-time decision support in the NICU in the very near future.
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Affiliation(s)
- Geraldine B Boylan
- Department of Paediatrics and Child Health, Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.
| | - Liudmila Kharoshankaya
- Department of Paediatrics and Child Health, Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland
| | - Sean R Mathieson
- Department of Paediatrics and Child Health, Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland
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8
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Almannai M, El-Hattab AW. Inborn Errors of Metabolism with Seizures: Defects of Glycine and Serine Metabolism and Cofactor-Related Disorders. Pediatr Clin North Am 2018; 65:279-299. [PMID: 29502914 DOI: 10.1016/j.pcl.2017.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Inborn errors of metabolism (IEM) are relatively uncommon causes for seizures in children; however, they should be considered in the differential diagnosis because several IEM are potentially treatable and seizures can be resolved if appropriate treatment is initiated. Clues from clinical presentation, physical examination, laboratory tests, and brain imaging can raise the possibility of IEM. Several IEM can present with seizures, either as the main presenting finding or as a part of a more complex phenotype. These include cofactor-related disorders, glycine and serine metabolism defects, and other disorders.
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Affiliation(s)
- Mohammed Almannai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Texas Children's Hospital, One Baylor Plaza, Houston, TX 77030, USA
| | - Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatrics Department, Tawam Hospital, Tawam Roundabout, Al-Ain 15258, United Arab Emirates.
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9
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Xue J, Chang X, Zhang Y, Yang Z. Novel phenotypes of pyridox(am)ine-5'-phosphate oxidase deficiency and high prevalence of c.445_448del mutation in Chinese patients. Metab Brain Dis 2017; 32:1081-1087. [PMID: 28349276 DOI: 10.1007/s11011-017-9995-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 03/13/2017] [Indexed: 01/11/2023]
Abstract
To analyze the clinical and genetic characteristics of Chinese patients with pyridox(am)ine-5'-phosphate oxidase (PNPO) deficiency. The clinical presentations and the responses to treatments were analyzed in 4 patients. Blood and urinary metabolic screenings, electroencephalogram (EEG), brain magnetic resonance imaging (MRI) and epilepsy-related genes detection were performed in all patients. Patient 1 and 2 were identical twin brothers, who were born at 35+5 w gestation with a sign of encephalopathy. Their seizures started within the first day and could not be controlled by pyridoxine or pyridoxal-5'-phosphate (PLP) completely. Patient 3 presented seizures at 5 months, responding well to pyridoxine. Seizures in patient 4 began at 40 days after birth and were controlled by valproic acid and topiramate. EEG showed atypical hypsarrhythmia or multifocal epileptiform discharges in 3 patients, and showed normality in patient 4. MRI showed nonspecific abnormality or normality. Blood metabolic screening showed multiple amino acids level abnormalities in all cases. Urinary metabolic screening showed vanillactic acid prominently elevated in 3 patients. Genetic analysis revealed 5 mutations of PNPO, three of which were novel. The mutation c.445_448del was carried by the twins and patient 3. Assessment of psychomotor development indicated severe delay in 3 patients and borderline to mild delay in patient 3. This is the first time to report patients with PNPO deficiency diagnosed by gene analysis in China. The novel clinical characteristics and novel mutations found here expanded the phenotypes and genotypes of this disease. Further, the frameshift mutation c.445_448del might be high prevalence in PNPO deficiency in Chinese patients.
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Affiliation(s)
- Jiao Xue
- Department of Pediatrics, Peking University First Hospital, No.1, Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Xingzhi Chang
- Department of Pediatrics, Peking University First Hospital, No.1, Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, No.1, Xi'anmen Street, Xicheng District, Beijing, 100034, China.
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, No.1, Xi'anmen Street, Xicheng District, Beijing, 100034, China.
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10
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Abstract
Pyridoxal phosphate (PLP) is the active form of vitamin B6 and a cofactor in many enzyme reactions including neurotransmitter metabolism. PLP metabolism disturbances may mostly lead to refractory seizures. In this report, we review the main pathophysiological factors related with PLP deficiency and our experience in PLP treatment in pediatric patients with low-normal cerebrospinal fluid PLP values who presented epilepsy. Only one case had a definite diagnosis (Phelan-McDermid syndrome). The results of extensive metabolic workups and targeted genetic studies were normal for all patients. In 5 cases, the response to PLP supplementation (10-30mg/kg/d) was initially positive. PLP adverse reactions were noticed in 4 patients and PLP was discontinued; however, one of the most noticeable symptoms was an asymptomatic increase in liver enzymes. These negative results with PLP supplementation are worth reporting, to improve the information we use to treat our patients.
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11
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Abstract
In this article, we review the treatment options for the pediatric epileptic encephalopathies and provide an update on the new and emerging therapies targeted at the underlying pathophysiology of many of these syndromes. We illustrate how the identification of the specific genetic and autoimmune causes has made possible the evaluation and development of novel, better targeted therapies, as and at times, avoidance of potentially offending agents.
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12
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Jaeger B, Abeling NG, Salomons GS, Struys EA, Simas-Mendes M, Geukers VG, Poll-The BT. Pyridoxine responsive epilepsy caused by a novel homozygous PNPO mutation. Mol Genet Metab Rep 2016; 6:60-3. [PMID: 27014579 PMCID: PMC4789384 DOI: 10.1016/j.ymgmr.2016.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/26/2016] [Accepted: 01/26/2016] [Indexed: 12/20/2022] Open
Abstract
We report a patient with anti-epileptic treatment refractory neonatal seizures responsive to pyridoxine. Biochemical analysis revealed normal markers for antiquitin deficiency and also mutation analysis of the ALDH7A1 (Antiquitin) gene was negative. Mutation analysis of the PNPO gene revealed a novel, homozygous, presumed pathogenic mutation (c.481C > T; p.(Arg161Cys)). Measurements of B6 vitamers in a CSF sample after pyridoxine administration revealed elevated pyridoxamine as the only metabolic marker for PNPO deficiency. With pyridoxine monotherapy the patient is seizure free and neurodevelopmental outcome at the age of 14 months is normal.
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Affiliation(s)
- B Jaeger
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
| | - N G Abeling
- Laboratory of Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands
| | - G S Salomons
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
| | - E A Struys
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
| | - M Simas-Mendes
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
| | - V G Geukers
- Pediatric Intensive Care Department, Academic Medical Center, Amsterdam, The Netherlands
| | - B T Poll-The
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
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13
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Ream MA, Patel AD. Obtaining genetic testing in pediatric epilepsy. Epilepsia 2015; 56:1505-14. [DOI: 10.1111/epi.13122] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2015] [Indexed: 12/11/2022]
Affiliation(s)
- Margie A. Ream
- Nationwide Children's Hospital; Columbus Ohio U.S.A
- The Ohio State University College of Medicine; Columbus Ohio U.S.A
| | - Anup D. Patel
- Nationwide Children's Hospital; Columbus Ohio U.S.A
- The Ohio State University College of Medicine; Columbus Ohio U.S.A
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14
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Normal Neurodevelopmental Outcomes in PNPO Deficiency: A Case Series and Literature Review. JIMD Rep 2015; 26:91-7. [PMID: 26303608 DOI: 10.1007/8904_2015_482] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 07/07/2015] [Accepted: 07/08/2015] [Indexed: 12/13/2022] Open
Abstract
Pyridox(am)ine 5'-phosphate oxidase deficiency results in an early-onset neonatal encephalopathy that can be fatal if not detected and treated early. The condition is rare, can result in preterm delivery, and can mimic hypoxic ischemic encephalopathy. Thus, suspicion of the diagnosis, appropriate investigations, and therapeutic trials with pyridoxal-5'-phosphate are often delayed. In this paper we report four cases of pyridox(am)ine 5'-phosphate oxidase deficiency, two of whom are siblings. Three were treated with pyridoxal-5'-phosphate in the first few days of life and the fourth within the first month. One of the siblings was electively treated from birth until a diagnosis was secured. Our cases demonstrate that early diagnosis and treatment can be associated with normal neurodevelopment in childhood. We suggest that a low threshold for investigating for pyridox(am)ine 5'-phosphate oxidase deficiency and electively treating with pyridoxal-5'-phosphate is considered in any neonate with encephalopathy, including those with presumed hypoxic ischemic encephalopathy in whom the degree of encephalopathy is not expected from perinatal history, cord gases and/or neuroimaging.
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Guerin A, Aziz AS, Mutch C, Lewis J, Go CY, Mercimek-Mahmutoglu S. Pyridox(am)ine-5-Phosphate Oxidase Deficiency Treatable Cause of Neonatal Epileptic Encephalopathy With Burst Suppression: Case Report and Review of the Literature. J Child Neurol 2015; 30:1218-25. [PMID: 25296925 DOI: 10.1177/0883073814550829] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 01/17/2014] [Indexed: 12/14/2022]
Abstract
Pyridox(am)ine-5-phosphate oxidase deficiency is an autosomal recessive disorder of pyridoxine metabolism. Intractable neonatal epileptic encephalopathy is the classical presentation. Pyridoxal-5-phosphate or pyridoxine supplementation improves symptoms. We report a patient with myoclonic and tonic seizures at the age of 1 hour. Pyridoxal-5-phosphate was started on the first day of life and seizures stopped at the age of 3 days, but encephalopathy persisted for 4 weeks. She had normal neurodevelopmental outcome at the age of 12 months on pyridoxal-5-phosphate monotherapy. She had novel homozygous pathogenic frameshift mutation (c.448_451del;p.Pro150Argfs*27) in the PNPO gene. Long-lasting encephalopathy despite well-controlled clinical seizures does neither confirm nor exclude pyridox(am)ine-5-phosphate oxidase deficiency. Normal neurodevelopmental outcome of our patient emphasizes the importance of pyridoxal-5-phosphate treatment. Pyridox(am)ine-5-phosphate oxidase deficiency should be included in the differential diagnosis of Ohtahara syndrome and neonatal myoclonic encephalopathy as a treatable underlying cause. In addition, we reviewed the literature for pyridox(am)ine-5-phosphate oxidase deficiency and summarized herein all confirmed cases.
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Affiliation(s)
- Andrea Guerin
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Toronto, Canada
| | - Aly S Aziz
- Division of Neurology, Department of Pediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Carly Mutch
- Occupational Therapy, Department of Rehabilitation Services, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jillian Lewis
- Division of Neonatology, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Cristina Y Go
- Division of Neurology, Department of Pediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Saadet Mercimek-Mahmutoglu
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Toronto, Canada Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Canada
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16
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Epilepsy and hippocampal neurodegeneration induced by glutamate decarboxylase inhibitors in awake rats. Epilepsy Res 2015; 116:27-33. [PMID: 26354164 DOI: 10.1016/j.eplepsyres.2015.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 11/20/2022]
Abstract
Glutamic acid decarboxylase (GAD), the enzyme responsible for GABA synthesis, requires pyridoxal phosphate (PLP) as a cofactor. Thiosemicarbazide (TSC) and γ-glutamyl-hydrazone (PLPGH) inhibit the free PLP-dependent isoform (GAD65) activity after systemic administration, leading to epilepsy in mice and in young, but not in adult rats. However, the competitive GAD inhibitor 3-mercaptopropionic acid (MPA) induces convulsions in both immature and adult rats. In the present study we tested comparatively the epileptogenic and neurotoxic effects of PLPGH, TSC and MPA, administered by microdialysis in the hippocampus of adult awake rats. Cortical EEG and motor behavior were analyzed during the next 2h, and aspartate, glutamate and GABA were measured by HPLC in the microdialysis-collected fractions. Twenty-four hours after drug administration rats were fixed for histological analysis of the hippocampus. PLPGH or TSC did not affect the motor behavior, EEG or cellular morphology, although the extracellular concentration of GABA was decreased. In contrast, MPA produced intense wet-dog shakes, EEG epileptiform discharges, a >75% reduction of extracellular GABA levels and remarkable neurodegeneration of the CA1 region, with >80% neuronal loss. The systemic administration of the NMDA glutamate receptor antagonist MK-801 30 min before MPA did not prevent the MPA-induced epilepsy but significantly protected against its neurotoxic effect, reducing neuronal loss to <30%. We conclude that in adult awake rats, drugs acting on PLP availability have only a weak effect on GABA neurotransmission, whereas direct GAD inhibition produced by MPA induces hyperexcitation leading to epilepsy and hippocampal neurodegeneration. Because this degeneration was prevented by the blockade of NMDA receptors, we conclude that it is due to glutamate-mediated excitotoxicity consequent to disinhibition of the hippocampal excitatory circuits.
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PNPO Deficiency and Cirrhosis: Expanding the Clinical Phenotype? JIMD Rep 2015; 25:71-75. [PMID: 26108646 DOI: 10.1007/8904_2015_456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 05/06/2015] [Accepted: 05/08/2015] [Indexed: 12/13/2022] Open
Abstract
We report the case of a 4-year-old boy with pyridoxamine 5-phosphate oxidase deficiency, now the second reported case to develop hepatic cirrhosis. He presented with an encephalopathy in the first 1.5 h of life and received a first dose of PLP at 40 h of life. PNPO gene sequencing identified homozygosity for a novel variant in exon 7, c.637C>T (p.Pro213Ser). Persistent elevations in alanine transferase and aspartate transferase combined with an echogenic liver on ultrasound prompted performance of a liver biopsy which demonstrated hepatic cirrhosis. This is the second reported case of hepatic cirrhosis in PNPO deficiency. The pathogenesis is unclear but may be related to epigenetic activation of purinergic signaling in the hepatic stellate cells. PNPO deficiency may in time prove to be a suitable candidate for consideration of therapeutic orthotropic liver transplantation in select patients.
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Abstract
As the genetic etiologies of an expanding number of epilepsy syndromes are revealed, the complexity of the phenotype genotype correlation increases. As our review will show, multiple gene mutations cause different epilepsy syndromes, making identification of the specific mutation increasingly more important for prognostication and often more directed treatment. Examples of that include the need to avoid specific drugs in Dravet syndrome and the ongoing investigations of the potential use of new directed therapies such as retigabine in KCNQ2-related epilepsies, quinidine in KCNT1-related epilepsies, and memantine in GRIN2A-related epilepsies.
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Affiliation(s)
- Abeer J Hani
- Division of Pediatric Neurology, Department of Pediatrics, Duke Children's Hospital and Health Center, Suite T0913J, 2301 Erwin Road, Durham, NC 27710, USA
| | - Husam M Mikati
- Center of Human Genome Variation, LSRC, Duke University School of Medicine, 201 Trent Drive, Durham, NC 27710, USA
| | - Mohamad A Mikati
- Division of Pediatric Neurology, Department of Pediatrics, Duke Children's Hospital and Health Center, Suite T0913J, 2301 Erwin Road, Durham, NC 27710, USA.
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Levtova A, Camuzeaux S, Laberge AM, Allard P, Brunel-Guitton C, Diadori P, Rossignol E, Hyland K, Clayton PT, Mills PB, Mitchell GA. Normal Cerebrospinal Fluid Pyridoxal 5'-Phosphate Level in a PNPO-Deficient Patient with Neonatal-Onset Epileptic Encephalopathy. JIMD Rep 2015; 22:67-75. [PMID: 25762494 DOI: 10.1007/8904_2015_413] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/23/2015] [Accepted: 01/26/2015] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Deficiency of pyridox(am)ine 5'-phosphate oxidase (PNPO, OMIM 610090) is a treatable autosomal recessive inborn error of metabolism. Neonatal epileptic encephalopathy and a low cerebrospinal fluid (CSF) pyridoxal 5'-phosphate level are the reported hallmarks of PNPO deficiency, but its clinical and biochemical spectra are not fully known. CASE PRESENTATION A girl born at 33 3/7 weeks of gestation developed seizures in the first hours of life. Her seizures initially responded to GABAergic agonists, but she subsequently developed a severe epileptic encephalopathy. Brain MRI and infectious and metabolic evaluations at birth, including urinary alpha-aminoadipic semialdehyde (AASA), were normal. Lumbar puncture at age 3 months showed: pyridoxal 5'-phosphate, 52 nmol/L (normal, 23-64); homovanillic acid, 392 nmol/L (normal, 450-1,132); 5-hydroxyindoleacetic acid, 341 nmol/L (normal, 179-711); and 3-ortho-methyldopa, 30 nmol/L (normal, below 300). The patient was not being treated with pyridoxine nor with pyridoxal 5'-phosphate at the time of the lumbar puncture. She died at age 14 months. A sequencing panel targeting 53 epilepsy-related genes revealed a homozygous missense mutation in PNPO (c.674G>A, p.R225H). Homozygosity was confirmed by parental testing. Expression studies of mutant p.R225H PNPO revealed greatly reduced activity. In conclusion, a normal CSF level of pyridoxal 5'-phosphate does not rule out PNPO deficiency.
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Affiliation(s)
- Alina Levtova
- Divisions of Medical Genetics (AL, AML, CBG, GM) and Neurology (PD, ER), Department of Paediatrics, Biochemical Genetics Laboratory (CBG, PA), CHU Sainte-Justine and Université de Montréal, 3175 Côte-Sainte-Catherine, Montreal, QC, Canada, H3T 1C5
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Plecko B, Paul K, Mills P, Clayton P, Paschke E, Maier O, Hasselmann O, Schmiedel G, Kanz S, Connolly M, Wolf N, Struys E, Stockler S, Abela L, Hofer D. Pyridoxine responsiveness in novel mutations of the PNPO gene. Neurology 2014; 82:1425-33. [PMID: 24658933 DOI: 10.1212/wnl.0000000000000344] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether patients with pyridoxine-responsive seizures but normal biomarkers for antiquitin deficiency and normal sequencing of the ALDH7A1 gene may have PNPO mutations. METHODS We sequenced the PNPO gene in 31 patients who fulfilled the above-mentioned criteria. RESULTS We were able to identify 11 patients carrying 3 novel mutations of the PNPO gene. In 6 families, a homozygous missense mutation p.Arg225His in exon 7 was identified, while 1 family was compound heterozygous for a novel missense mutation p.Arg141Cys in exon 5 and a deletion c.279_290del in exon 3. Pathogenicity of the respective mutations was proven by absence in 100 control alleles and expression studies in CHO-K1 cell lines. The response to pyridoxine was prompt in 4, delayed in 2, on EEG only in 2, and initially absent in another 2 patients. Two unrelated patients homozygous for the p.Arg225His mutation experienced status epilepticus when switched to pyridoxal 5'-phosphate (PLP). CONCLUSIONS This study challenges the paradigm of exclusive PLP responsiveness in patients with pyridoxal 5'-phosphate oxidase deficiency and underlines the importance of consecutive testing of pyridoxine and PLP in neonates with antiepileptic drug-resistant seizures. Patients with pyridoxine response but normal biomarkers for antiquitin deficiency should undergo PNPO mutation analysis.
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Affiliation(s)
- Barbara Plecko
- From the Department of Pediatrics (B.P., L.A.), Division of Child Neurology, University Hospital Zurich, Switzerland; the Department of Pediatrics (B.P.), Division of Neurology and Inborn Errors of Metabolism, Medical University Graz, Austria; radiz-"Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases University of Zurich" (B.P., L.A.); CRC Clinical Research Center (B.P.), University Childrens' Hospital Zurich, Switzerland; the Laboratory of Metabolic Diseases (K.P., E.P., D.H.), Department of Pediatrics, University Hospital Graz, Austria; UCL Institute of Child Health (P.M., P.C.), Clinical and Molecular Genetics Unit, London, UK; Childrens Hospital St. Gallen (O.M., O.H.), Switzerland; the Department of Pediatrics (G.H.), Klinikum Esslingen; the Department of Pediatrics (S.K.), St. Marien Hospital, Landshut, Germany; the Division of Child Neurology (M.C.) and Division of Biochemical Diseases (S.S.), Department of Pediatrics, University of British Columbia, Vancouver, Canada; the Department of Pediatrics, Division of Child Neurology (N.W.), VU University Medical Center and Neuroscience Campus Amsterdam; and the Department of Clinical Chemistry (E.S.), Vrije Universiteit Amsterdam, the Netherlands
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21
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Mills PB, Camuzeaux SSM, Footitt EJ, Mills KA, Gissen P, Fisher L, Das KB, Varadkar SM, Zuberi S, McWilliam R, Stödberg T, Plecko B, Baumgartner MR, Maier O, Calvert S, Riney K, Wolf NI, Livingston JH, Bala P, Morel CF, Feillet F, Raimondi F, Del Giudice E, Chong WK, Pitt M, Clayton PT. Epilepsy due to PNPO mutations: genotype, environment and treatment affect presentation and outcome. Brain 2014; 137:1350-60. [PMID: 24645144 PMCID: PMC3999720 DOI: 10.1093/brain/awu051] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The first described patients with pyridox(am)ine 5'-phosphate oxidase deficiency all had neonatal onset seizures that did not respond to treatment with pyridoxine but responded to treatment with pyridoxal 5'-phosphate. Our data suggest, however, that the clinical spectrum of pyridox(am)ine 5'-phosphate oxidase deficiency is much broader than has been reported in the literature. Sequencing of the PNPO gene was undertaken for a cohort of 82 individuals who had shown a reduction in frequency and severity of seizures in response to pyridoxine or pyridoxal 5'-phosphate. Novel sequence changes were studied using a new cell-free expression system and a mass spectrometry-based assay for pyridoxamine phosphate oxidase. Three groups of patients with PNPO mutations that had reduced enzyme activity were identified: (i) patients with neonatal onset seizures responding to pyridoxal 5'-phosphate (n = 6); (ii) a patient with infantile spasms (onset 5 months) responsive to pyridoxal 5'-phosphate (n = 1); and (iii) patients with seizures starting under 3 months of age responding to pyridoxine (n = 8). Data suggest that certain genotypes (R225H/C and D33V) are more likely to result in seizures that to respond to treatment with pyridoxine. Other mutations seem to be associated with infertility, miscarriage and prematurity. However, the situation is clearly complex with the same combination of mutations being seen in patients who responded and did not respond to pyridoxine. It is possible that pyridoxine responsiveness in PNPO deficiency is affected by prematurity and age at the time of the therapeutic trial. Other additional factors that are likely to influence treatment response and outcome include riboflavin status and how well the foetus has been supplied with vitamin B6 by the mother. For some patients there was a worsening of symptoms on changing from pyridoxine to pyridoxal 5'-phosphate. Many of the mutations in PNPO affected residues involved in binding flavin mononucleotide or pyridoxal 5'-phosphate and many of them showed residual enzyme activity. One sequence change (R116Q), predicted to affect flavin mononucleotide binding and binding of the two PNPO dimers, and with high residual activity was found in Groups (ii) and (iii). This sequence change has been reported in the 1000 Genomes project suggesting it could be a polymorphism but alternatively it could be a common mutation, perhaps responsible for the susceptibility locus for genetic generalized epilepsy on 17q21.32 (close to rs72823592). We believe the reduction in PNPO activity and B6-responsive epilepsy in the patients reported here indicates that it contributes to the pathogenesis of epilepsy.
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Affiliation(s)
- Philippa B Mills
- 1 Clinical and Molecular Genetics Unit, UCL Institute of Child Health, 30 Guilford St, London WC1N 1EH, UK
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22
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Tabarki B, Thabet F. [Vitamin-responsive epilepsies: an update]. Arch Pediatr 2013; 20:1236-1241. [PMID: 24080039 DOI: 10.1016/j.arcped.2013.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/01/2013] [Accepted: 08/12/2013] [Indexed: 11/22/2022]
Abstract
Inborn error of metabolism may produce a complex clinical picture in which epilepsy is only one of the various neurologic manifestations including developmental delay/regression, mental retardation, and movement disorders. However, metabolic epilepsies may dominate the clinical presentation. A specific diagnosis of metabolic disorders in epileptic patients may provide the possibility of specific treatments that can improve seizures. In a few metabolic diseases such as vitamin-responsive epilepsies, epilepsy responds to specific treatments based on supplementation of cofactors. Certain rare vitamin-responsive inborn errors of metabolism may present as early encephalopathy with anticonvulsant-resistant seizures. These include pyridoxine-dependent seizures, pyridoxal-phosphate-dependent seizures, folinic acid-responsive seizures, and biotinidase deficiency. This review discusses our current understanding of these vitamin-responsive epilepsies.
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Affiliation(s)
- B Tabarki
- Service de neuropédiatrie, département de pédiatrie, hôpital Militaire, P.O Box 7897, Riyadh 11159, Arabie saoudite.
| | - F Thabet
- Service de réanimation pédiatrique, département de pédiatrie, hôpital Militaire, Riyadh, Arabie saoudite
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23
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Goyal M, Fequiere PR, McGrath TM, Hyland K. Seizures with decreased levels of pyridoxal phosphate in cerebrospinal fluid. Pediatr Neurol 2013; 48:227-31. [PMID: 23419474 DOI: 10.1016/j.pediatrneurol.2012.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Accepted: 11/19/2012] [Indexed: 10/27/2022]
Abstract
Although pyridoxine-dependent seizures have been reported for decades, pyridoxamine phosphate oxidase deficiency has only been recently described. Pyridoxamine phosphate oxidase (PNPO) is one of a series of enzymes involved in converting pyridoxine to pyridoxal 5'-phosphate, the biologically active form of pyridoxine. PNPO deficiency is associated with decreased levels of pyridoxal 5'-phosphate in CSF, as well as epilepsy. We describe four children up to 16 years of age with intractable seizures who all had low cerebrospinal fluid (CSF) levels of pyridoxal 5'-phosphate. Only one of the four children possessed a genetic alteration, a novel homozygous variant in exon one of the PNPO gene. Three of four, however, showed at least some clinical improvement with pyridoxal 5'-phosphate supplementation. Low CSF pyridoxal 5'-phosphate levels, although considered a diagnostic biomarker for PNPO deficiency, lack specificity and may result from multiple other causes. Genetic testing and CSF evaluation, along with clinical response are all necessary for accurate diagnosis.
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Affiliation(s)
- Monisha Goyal
- Department of Pediatric Neurology, University of Alabama, Birmingham, AL 35233, USA.
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Noh GJ, Jane Tavyev Asher Y, Graham JM. Clinical review of genetic epileptic encephalopathies. Eur J Med Genet 2012; 55:281-98. [PMID: 22342633 DOI: 10.1016/j.ejmg.2011.12.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Accepted: 12/27/2011] [Indexed: 11/29/2022]
Abstract
Seizures are a frequently encountered finding in patients seen for clinical genetics evaluations. The differential diagnosis for the cause of seizures is quite diverse and complex, and more than half of all epilepsies have been attributed to a genetic cause. Given the complexity of such evaluations, we highlight the more common causes of genetic epileptic encephalopathies and emphasize the usefulness of recent technological advances. The purpose of this review is to serve as a practical guide for clinical geneticists in the evaluation and counseling of patients with genetic epileptic encephalopathies. Common syndromes will be discussed, in addition to specific seizure phenotypes, many of which are refractory to anti-epileptic agents. Divided by etiology, we overview the more common causes of infantile epileptic encephalopathies, channelopathies, syndromic, metabolic, and chromosomal entities. For each condition, we will outline the diagnostic evaluation and discuss effective treatment strategies that should be considered.
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Affiliation(s)
- Grace J Noh
- Clinical Genetics and Dysmorphology, Medical Genetics Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
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25
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Affiliation(s)
- Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Instituto Neurologico Carlo Besta, Milan, Italy.
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van der Ham M, Albersen M, de Koning T, Visser G, Middendorp A, Bosma M, Verhoeven-Duif N, de Sain-van der Velden M. Quantification of vitamin B6 vitamers in human cerebrospinal fluid by ultra performance liquid chromatography–tandem mass spectrometry. Anal Chim Acta 2012; 712:108-14. [DOI: 10.1016/j.aca.2011.11.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/17/2011] [Accepted: 11/08/2011] [Indexed: 10/15/2022]
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