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In Silico Prediction of the Mode of Action of Viola odorata in Diabetes. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2768403. [PMID: 33490239 PMCID: PMC7803256 DOI: 10.1155/2020/2768403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/27/2020] [Accepted: 10/05/2020] [Indexed: 12/17/2022]
Abstract
Background The metabolic syndrome increases the risk of different diseases such as type 2 diabetes. The prevalence of metabolic syndrome has rapidly grown and affected more than 230 million people worldwide. Viola odorata is a traditionally used plant for the treatment of diabetes; however, its mechanism to manage diabetes is still unknown. Purpose This study was designed to systematically assess the mechanism of action of Viola odorata in diabetes. Methods An extensive literature search was made to establish an ingredient-target database of Viola odorata. Of these, targets related to diabetes were identified and used to develop a protein-protein interaction network (PPIN) by utilizing the STITCH database. The obtained PPIN was assessed through Gene Ontology (GO) enrichment analysis based on ClueGO plugin. Results According to the acquired data, there were about 143 chemical constituents present in Viola odorata having 119 protein targets. Of these, 31 targets were established to give the pharmacological effect against diabetes. The UniProt database was used for screening of 31 targets, out of which Homo sapiens contained 22 targets. Ultimately, 207 GO terms, grouped into 41 clusters, were found by gene analysis, and most of them were found to be linked with diabetes. According to findings, several proteins including TP53, BCL2, CDKN1A, 1L6, CCND1, CDKN2A, and RB1 have a significant role in the treatment of diabetes by Viola odorata. Conclusion The possible activity of Viola odorata in the management of diabetes may be mediated by several molecular mechanisms, including the glutamine metabolic process, IRE1-mediated unfolded protein response, and pentose metabolic process.
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Abstract
West syndrome (WS) is an early life epileptic encephalopathy associated with infantile spasms, interictal electroencephalography (EEG) abnormalities including high amplitude, disorganized background with multifocal epileptic spikes (hypsarrhythmia), and often neurodevelopmental impairments. Approximately 64% of the patients have structural, metabolic, genetic, or infectious etiologies and, in the rest, the etiology is unknown. Here we review the contribution of etiologies due to various metabolic disorders in the pathology of WS. These may include metabolic errors in organic molecules involved in amino acid and glucose metabolism, fatty acid oxidation, metal metabolism, pyridoxine deficiency or dependency, or acidurias in organelles such as mitochondria and lysosomes. We discuss the biochemical, clinical, and EEG features of these disorders as well as the evidence of how they may be implicated in the pathogenesis and treatment of WS. The early recognition of these etiologies in some cases may permit early interventions that may improve the course of the disease.
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Affiliation(s)
- Seda Salar
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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Yang Z, Yang X, Wu Y, Wang J, Zhang Y, Xiong H, Jiang Y, Qin J. Clinical diagnosis, treatment, and ALDH7A1 mutations in pyridoxine-dependent epilepsy in three Chinese infants. PLoS One 2014; 9:e92803. [PMID: 24664145 PMCID: PMC3963937 DOI: 10.1371/journal.pone.0092803] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/26/2014] [Indexed: 11/19/2022] Open
Abstract
Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive disorder that causes seizures in neonates and infants. Mutations of the ALDH7A1 gene are now recognized as the molecular basis PDE and help to define this disease. Three Chinese children with PDE were clinically analyzed, followed by treatment and examination of the ALDH7A1 mutations. The seizures of the 3 patients were all resistant to multiple anticonvulsants (2 to 7 types). For case 1, onset of seizures was at the age of 2 months. His seizures were well controlled by intravenous pyridoxine for several days at the age of 3 months 20 days and recurred at intervals of 13, 14 and 38 days after pyridoxine withdrawn for 3 times. At the age of 7 months, symptoms of PDE appeared and uninterrupted oral pyridoxine started. For case 2, her seizures occurred at 8 days after birth. After administration of multiple antiepileptic drugs observed ineffective, high-dose pyridoxine continuous therapy was taken at the age of 10 months and the significant treatment effect induced a diagnostic PDE. Seizure onset in case 3 was at the first day of birth. He experienced inadvertently pyridoxine therapy several times (first time at 2 days after birth) and achieved good therapeutic effect, which was confirmed by physicians until 4 months 10 days. The treatment process in our 3 patients suggested that pyridoxine should be early and purposefully used in patients with early onset seizures. ALDH7A1 gene mutation analysis revealed compound heterozygous mutations in each case: heterozygous c.410G>A (p.G137E) and IVS11+1G>A in case 1, heterozygous c.952G>C (p.A318P) and heterozygous c.965C>T (p.A322V) in case 2, and heterozygous c.902A>T (p.N301I) and IVS11+1G>A in case 3. Only p.N301I was reported previously, all other mutations were novel. This is the first time to report cases of Chinese patients diagnosed with PDE by molecular genetic analysis.
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Affiliation(s)
- Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
- * E-mail:
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
| | - Jiong Qin
- Department of Pediatrics, Peking University First Hospital, Xicheng District, Beijing, China
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4
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Hallen A, Jamie JF, Cooper AJL. Lysine metabolism in mammalian brain: an update on the importance of recent discoveries. Amino Acids 2013. [PMID: 24043460 DOI: 10.1007/s00726-013-1590-1591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The lysine catabolism pathway differs in adult mammalian brain from that in extracerebral tissues. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. The two pathways converge at the level of ∆(1)-piperideine-6-carboxylate (P6C), which is in equilibrium with its open-chain aldehyde form, namely, α-aminoadipate δ-semialdehyde (AAS). A unique feature of the pipecolate pathway is the formation of the cyclic ketimine intermediate ∆(1)-piperideine-2-carboxylate (P2C) and its reduced metabolite L-pipecolate. A cerebral ketimine reductase (KR) has recently been identified that catalyzes the reduction of P2C to L-pipecolate. The discovery that this KR, which is capable of reducing not only P2C but also other cyclic imines, is identical to a previously well-described thyroid hormone-binding protein [μ-crystallin (CRYM)], may hold the key to understanding the biological relevance of the pipecolate pathway and its importance in the brain. The finding that the KR activity of CRYM is strongly inhibited by the thyroid hormone 3,5,3'-triiodothyronine (T3) has far-reaching biomedical and clinical implications. The inter-relationship between tryptophan and lysine catabolic pathways is discussed in the context of shared degradative enzymes and also potential regulation by thyroid hormones. This review traces the discoveries of enzymes involved in lysine metabolism in mammalian brain. However, there still remain unanswered questions as regards the importance of the pipecolate pathway in normal or diseased brain, including the nature of the first step in the pathway and the relationship of the pipecolate pathway to the tryptophan degradation pathway.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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5
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Ville D, Ginguene C, Marignier S, des Portes V, de Bellescize J. Early diagnosis of pyridoxine-dependent epilepsy: video-EEG monitoring and biochemical and genetic investigation. Eur J Paediatr Neurol 2013; 17:676-80. [PMID: 23916709 DOI: 10.1016/j.ejpn.2013.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 06/04/2013] [Accepted: 06/29/2013] [Indexed: 11/28/2022]
Abstract
Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive metabolic disease. A delay of treatment may affect outcome and early initiation of pyridoxine based on effective diagnosis is crucial to ensure good cognitive outcome in neonates. A consensus for the diagnosis of PDE is based on refractive seizures and responsiveness to pyridoxine, however, a growing body of evidence suggests that additional elements should be considered which include biochemical data, genetic screening, and EEG monitoring. We present a case study of a neonate with PDE, who presented with misleading clinical presentation and a novel mutation in the antiquitin (ALDH7A1) gene (A294V), and highlight important aspects in order to consider the definition of diagnosis and management of PDE in the light of more recent data.
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Affiliation(s)
- Dorothée Ville
- Pediatric Neurology Department and Center of Reference for Rare Intellectual Disorders, Tuberous Sclerosis and Rare Epileptic Disorders, University Hospitals of Lyon (HCL), Lyon, France.
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6
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Hallen A, Jamie JF, Cooper AJL. Lysine metabolism in mammalian brain: an update on the importance of recent discoveries. Amino Acids 2013; 45:1249-72. [PMID: 24043460 DOI: 10.1007/s00726-013-1590-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 12/23/2022]
Abstract
The lysine catabolism pathway differs in adult mammalian brain from that in extracerebral tissues. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. The two pathways converge at the level of ∆(1)-piperideine-6-carboxylate (P6C), which is in equilibrium with its open-chain aldehyde form, namely, α-aminoadipate δ-semialdehyde (AAS). A unique feature of the pipecolate pathway is the formation of the cyclic ketimine intermediate ∆(1)-piperideine-2-carboxylate (P2C) and its reduced metabolite L-pipecolate. A cerebral ketimine reductase (KR) has recently been identified that catalyzes the reduction of P2C to L-pipecolate. The discovery that this KR, which is capable of reducing not only P2C but also other cyclic imines, is identical to a previously well-described thyroid hormone-binding protein [μ-crystallin (CRYM)], may hold the key to understanding the biological relevance of the pipecolate pathway and its importance in the brain. The finding that the KR activity of CRYM is strongly inhibited by the thyroid hormone 3,5,3'-triiodothyronine (T3) has far-reaching biomedical and clinical implications. The inter-relationship between tryptophan and lysine catabolic pathways is discussed in the context of shared degradative enzymes and also potential regulation by thyroid hormones. This review traces the discoveries of enzymes involved in lysine metabolism in mammalian brain. However, there still remain unanswered questions as regards the importance of the pipecolate pathway in normal or diseased brain, including the nature of the first step in the pathway and the relationship of the pipecolate pathway to the tryptophan degradation pathway.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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7
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Tlili A, Hamida Hentati N, Chaabane R, Gargouri A, Fakhfakh F. Pyridoxine-dependent epilepsy in Tunisia is caused by a founder missense mutation of the ALDH7A1 gene. Gene 2013; 518:242-5. [DOI: 10.1016/j.gene.2013.01.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/07/2013] [Accepted: 01/22/2013] [Indexed: 11/27/2022]
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8
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Plecko B. Pyridoxine and pyridoxalphosphate-dependent epilepsies. HANDBOOK OF CLINICAL NEUROLOGY 2013; 113:1811-7. [PMID: 23622403 DOI: 10.1016/b978-0-444-59565-2.00050-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
To date we know of four inborn errors of autosomal recessive inheritance that lead to vitamin B6-dependent seizures. Among these, pyridoxine-dependent seizures due to antiquitin deficiency is by far the most common, although exact incidence data are lacking. In PNPO deficiency, samples have to be collected prior to treatment, while PDE, hyperprolinemia type II and congenital HPP can be diagnosed while on vitamin B6 supplementation. A vitamin B6 withdrawal for diagnostic purposes is nowadays only indicated in patients with a clear vitamin B6 response but normal biochemical work-up. In the presence of therapy-resistant neonatal seizures, early consideration of a vitamin B6 trial over 3 consecutive days is crucial in order to prevent irreversible brain damage. While PLP would be effective in all four disorders, pyridoxine fails to treat seizures in PNPO deficiency. As PLP is unlicensed within Europe and North America, pyridoxine is widely used as the first line drug, but if it is ineffective it should be followed by a trial with PLP, especially in neonates. As severe apnea has been described in responders, resuscitation equipment should be at hand during a first pyridoxine/PLP administration. Patients and parents have to be informed about the lifelong dependency and recurrence risks in forthcoming pregnancies.
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Affiliation(s)
- Barbara Plecko
- Department of Pediatrics, University of Zurich, Zurich, Switzerland.
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9
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Identification of a novel missense mutation in the ALDH7A1 gene in two unrelated Tunisian families with pyridoxine-dependent epilepsy. Mol Biol Rep 2012; 40:487-90. [DOI: 10.1007/s11033-012-2084-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/03/2012] [Indexed: 10/27/2022]
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10
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Dolina S, Margalit D, Malitsky S, Pressman E, Rabinkov A. Epilepsy as a pyridoxine-dependent condition: Quantified urinary biomarkers for status evaluation and monitoring antiepileptic treatment. Med Hypotheses 2012; 79:157-64. [DOI: 10.1016/j.mehy.2012.04.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
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11
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Stockler S, Plecko B, Gospe SM, Coulter-Mackie M, Connolly M, van Karnebeek C, Mercimek-Mahmutoglu S, Hartmann H, Scharer G, Struijs E, Tein I, Jakobs C, Clayton P, Van Hove JLK. Pyridoxine dependent epilepsy and antiquitin deficiency: clinical and molecular characteristics and recommendations for diagnosis, treatment and follow-up. Mol Genet Metab 2011; 104:48-60. [PMID: 21704546 DOI: 10.1016/j.ymgme.2011.05.014] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 11/18/2022]
Abstract
Antiquitin (ATQ) deficiency is the main cause of pyridoxine dependent epilepsy characterized by early onset epileptic encephalopathy responsive to large dosages of pyridoxine. Despite seizure control most patients have intellectual disability. Folinic acid responsive seizures (FARS) are genetically identical to ATQ deficiency. ATQ functions as an aldehyde dehydrogenase (ALDH7A1) in the lysine degradation pathway. Its deficiency results in accumulation of α-aminoadipic semialdehyde (AASA), piperideine-6-carboxylate (P6C) and pipecolic acid, which serve as diagnostic markers in urine, plasma, and CSF. To interrupt seizures a dose of 100 mg of pyridoxine-HCl is given intravenously, or orally/enterally with 30 mg/kg/day. First administration may result in respiratory arrest in responders, and thus treatment should be performed with support of respiratory management. To make sure that late and masked response is not missed, treatment with oral/enteral pyridoxine should be continued until ATQ deficiency is excluded by negative biochemical or genetic testing. Long-term treatment dosages vary between 15 and 30 mg/kg/day in infants or up to 200 mg/day in neonates, and 500 mg/day in adults. Oral or enteral pyridoxal phosphate (PLP), up to 30 mg/kg/day can be given alternatively. Prenatal treatment with maternal pyridoxine supplementation possibly improves outcome. PDE is an organic aciduria caused by a deficiency in the catabolic breakdown of lysine. A lysine restricted diet might address the potential toxicity of accumulating αAASA, P6C and pipecolic acid. A multicenter study on long term outcomes is needed to document potential benefits of this additional treatment. The differential diagnosis of pyridoxine or PLP responsive seizure disorders includes PLP-responsive epileptic encephalopathy due to PNPO deficiency, neonatal/infantile hypophosphatasia (TNSALP deficiency), familial hyperphosphatasia (PIGV deficiency), as well as yet unidentified conditions and nutritional vitamin B6 deficiency. Commencing treatment with PLP will not delay treatment in patients with pyridox(am)ine phosphate oxidase (PNPO) deficiency who are responsive to PLP only.
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Affiliation(s)
- Sylvia Stockler
- Division of Biochemical Diseases, British Columbia Children's Hospital, University of British Columbia, 4480 Oak Street, Vancouver BC, Canada V6H 3V4.
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12
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Millet A, Salomons GS, Cneude F, Corne C, Debillon T, Jakobs C, Struys E, Hamelin S. Novel mutations in pyridoxine-dependent epilepsy. Eur J Paediatr Neurol 2011; 15:74-7. [PMID: 20427214 DOI: 10.1016/j.ejpn.2010.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 03/24/2010] [Accepted: 03/26/2010] [Indexed: 11/25/2022]
Abstract
PURPOSE Pyridoxine-Dependent Epilepsy (PDE) is a rare autosomal recessive disease with neonatal seizures resistant to conventional anti-epileptic drugs. This metabolic disease has to be diagnosed early and treated to improve outcome. We report on two new mutations that open new prenatal prospects and suggest a new diagnostic procedure. CASE REPORT We describe PDE in a neonate carrying two novel mutations in the ALDH7A1 gene: c.[852_856delCTTAG] + [1230C > A]; p.[(Phe410Leu)] + p.[(Leu285CysfsX26)]. This case also illustrates that diagnosis could have been made without any pyridoxine withdrawal, thanks to the measurement of biomarkers. The patient was successfully treated with pyridoxine supplementation and currently shows normal neurological development.
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Affiliation(s)
- A Millet
- Division of Neonatology, Department of Paediatrics, Grenoble University Hospital, France
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13
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The Canadian League Against Epilepsy 2007 Conference Supplement. Can J Neurol Sci 2009. [DOI: 10.1017/s0317167100008805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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14
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Striano P, Battaglia S, Giordano L, Capovilla G, Beccaria F, Struys EA, Salomons GS, Jakobs C. Two novel ALDH7A1 (antiquitin) splicing mutations associated with pyridoxine-dependent seizures. Epilepsia 2009; 50:933-6. [PMID: 18717709 DOI: 10.1111/j.1528-1167.2008.01741.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyridoxine-dependent seizures (PDS) is a rare autosomal recessive disorder causing intractable seizures in neonates and infants. Patients are typically resistant to conventional anticonvulsants but respond well to the administration of pyridoxine. We report two unrelated patients affected with PDS as a result of alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase deficiency caused by pathogenic ALDH7A1/antiquitin mutations. Two of the three reported mutations are novel and result in erroneous splicing, as showed by messenger RNA (mRNA) studies. So far, the vast majority of the patients clinically diagnosed as PDS show alpha-AASA dehydrogenase deficiency, caused by mutations in the ALDH7A1 gene. However, despite the availability of reliable biomarkers, early consideration of a pyridoxine trial is still the most important issue in a child with therapy-resistant seizures.
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Affiliation(s)
- Pasquale Striano
- Department of Neurological Sciences, Epilepsy Center, Federico II University, Napoli, Italy.
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15
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Pearl PL. New treatment paradigms in neonatal metabolic epilepsies. J Inherit Metab Dis 2009; 32:204-13. [PMID: 19234868 DOI: 10.1007/s10545-009-1045-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 12/23/2008] [Accepted: 01/06/2009] [Indexed: 10/21/2022]
Abstract
Neonatal seizures represent a major challenge among the epilepsies vis-à-vis seizure classification, electroclinical correlation, inherent excitability of neocortex, ontogenic characteristics of neurotransmitter receptors, and responsiveness to standard antiepileptic drugs. Each of these factors renders neonatal seizures more difficult to treat, and therapy has been a vexing area for recent advances in this seizure category. Conversely, specific metabolic disorders have very special therapeutic considerations in the clinical setting of neonatal seizures which require a high index of clinical suspicion and rapid intervention for a successful outcome. The prototype is pyridoxine dependency, although pyridoxal 5'-phosphate dependency is a recently recognized but treatable neonatal epilepsy that deserves earmarked distinction. Clinicians must remain vigilant for these possibilities, including atypical cases where apparent seizure-free intervals may occur. Folinic acid-dependent seizures are allelic with pyridoxine dependency. Serine-dependent seizures and glucose transporter deficiency may present with neonatal seizures and have specific therapy. A vital potassium channel regulated by serum ATP/ADP ratios in the pancreas and brain may be mutated with a resultant neuroendocrinopathy characterized by development delay, epilepsy, and neonatal diabetes (DEND). This requires oral hypoglycaemic therapy, and not insulin, for neurological responsiveness. The startle syndrome of hyperekplexia, which mimics neonatal epilepsy, has been associated with laryngospasm and sudden death but is treated with benzodiazepines.
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Affiliation(s)
- P L Pearl
- Department of Neurology, Neuroscience Center of Excellence and Clinical Research Institute, Children's National Medical Center, George Washington University School of Medicine, Washington, DC, USA.
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16
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Kabakus N, Aydin M, Ugur SA, Durukan M, Tolun A. Very-late-onset pyridoxine-dependent seizures not linking to the known 5q31 locus. Pediatr Int 2008; 50:703-5. [PMID: 19261126 DOI: 10.1111/j.1442-200x.2008.02712.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Nimet Kabakus
- Department of Pediatric Neurology, Faculty of Medicine, Firat University, Elazig, Turkey
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17
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Grill MF, Losey TE, Ng YT. The Hitchhiker's guide to the child neurologist's genetic evaluation of epilepsy. Semin Pediatr Neurol 2008; 15:32-40. [PMID: 18342259 DOI: 10.1016/j.spen.2008.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Over the past several decades, familial aggregation studies as well as twin studies have supported a genetic component to seizures. The recent advent of the genome project has served as a catalyst in the search for elucidating the hereditary influences of various epilepsies. Overlapping seizure features may lead to ambiguity when attempting to isolate a single phenotype. Conversely, the phenomenon of genetic heterogeneity implies that multiple genetic mutations may give rise to a similar phenotype. Despite valiant attempts at strictly defining epilepsy phenotype and mode of penetrance, one must also consider the role of environment in gene expression. Genetics (testing) in epilepsy is no longer limited to the idiopathic epilepsies but may have an equally significant role in the symptomatic epilepsies. This article guides the reader through the genetics of epilepsy via discussion of the phenotypic description of known genetic childhood epilepsy syndromes, illustration of the associated gene mutations identified thus far, and the implications of genetic testing in clinical practice.
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Affiliation(s)
- Marie F Grill
- Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA
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18
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Lee YM. Epilepsy in various metabolic disorders. KOREAN JOURNAL OF PEDIATRICS 2008. [DOI: 10.3345/kjp.2008.51.12.1290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Young-Mock Lee
- Department of Pediatrics, Yonsei University Collegy of Medicine, Seoul, Korea
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Kanno J, Kure S, Narisawa A, Kamada F, Takayanagi M, Yamamoto K, Hoshino H, Goto T, Takahashi T, Haginoya K, Tsuchiya S, Baumeister FAM, Hasegawa Y, Aoki Y, Yamaguchi S, Matsubara Y. Allelic and non-allelic heterogeneities in pyridoxine dependent seizures revealed by ALDH7A1 mutational analysis. Mol Genet Metab 2007; 91:384-9. [PMID: 17433748 DOI: 10.1016/j.ymgme.2007.02.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Accepted: 02/15/2007] [Indexed: 11/24/2022]
Abstract
Pyridoxine dependent seizure (PDS) is a disorder of neonates or infants with autosomal recessive inheritance characterized by seizures, which responds to pharmacological dose of pyridoxine. Recently, mutations have been identified in the ALDH7A1 gene in Caucasian families with PDS. To elucidate further the genetic background of PDS, we screened for ALDH7A1 mutations in five PDS families (patients 1-5) that included four Orientals. Diagnosis as having PDS was confirmed by pyridoxine-withdrawal test. Exon sequencing analysis of patients 1-4 revealed eight ALDH7A1 mutations in compound heterozygous forms: five missense mutations, one nonsense mutation, one point mutation at the splicing donor site in intron 1, and a 1937-bp genomic deletion. The deletion included the entire exon 17, which was flanked by two Alu elements in introns 16 and 17. None of the mutations was found in 100 control chromosomes. In patient 5, no mutation was found by the exon sequencing analysis. Furthermore, expression level or nucleotide sequences of ALDH7A1 mRNA in lymphoblasts were normal. Plasma pipecolic acid concentration was not elevated in patient 5. These observations suggest that ALDH7A1 mutation is unlikely to be responsible for patient 5. Abnormal metabolism of GABA/glutamate in brain has long been suggested as the underlying pathophysiology of PDS. CSF glutamate concentration was elevated during the off-pyridoxine period in patient 3, but not in patient 2 or 5. These results suggest allelic and non-allelic heterogeneities of PDS, and that the CSF glutamate elevation does not directly correlate with the presence of ALDH7A1 mutations.
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Affiliation(s)
- Junko Kanno
- Department of Medical Genetics, Tohoku University School of Medicine, 1-1 Seiryomachi, Aobaku, Sendai 980-8574, Japan
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Santana Cabrera L, Amela R, Rodríguez González F, Sánchez-Palacios M. [Status epilepticus due to low vitamin B6 levels refractory to convencional antiepileptic treatment during pregnancy]. Med Clin (Barc) 2007; 129:239. [PMID: 17678610 DOI: 10.1157/13107933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The pediatric neurotransmitter disorders represent an enlarging group of neurological syndromes characterized by abnormalities of neurotransmitter synthesis and breakdown. The disorders of dopamine and serotonin synthesis are aromatic amino acid decarboxylase deficiency, tyrosine hydroxylase deficiency, and disorders of tetrahydrobiopterin synthesis. Amino acid decarboxylase, tyrosine hydroxylase, sepiapterin reductase, and guanosine triphosphate cyclohydrolase (Segawa disease) deficiencies do not feature elevated serum phenylalanine and require cerebrospinal fluid analysis for diagnosis. Segawa disease is characterized by dramatic and lifelong responsiveness to levodopa. Glycine encephalopathy is typically manifested by refractory neonatal seizures secondary to a defect of the glycine degradative pathway. gamma-amino butyric acid (GABA) metabolism is associated with several disorders, including glutamic acid decarboxylase deficiency with nonsyndromic cleft lip/ palate, GABA-transaminase deficiency, and succinic semialdehyde dehydrogenase deficiency. The latter is characterized by elevated gamma-hydroxybutyric acid and includes a wide range of neuropsychiatric symptoms as well as epilepsy. Pyridoxine-dependent seizures have now been associated with deficiency of alpha-aminoadipic semialdehyde dehydrogenase, as well as a new variant requiring therapy with pyridoxal-5-phosphate, the biologically active form of pyridoxine.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Children's National Medical Center, The George Washington University School of Medicine, Washington, DC 20010, USA.
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22
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Leonard JV. Recent advances in amino acid and organic acid metabolism. J Inherit Metab Dis 2007; 30:134-8. [PMID: 17237988 DOI: 10.1007/s10545-006-0524-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 11/27/2006] [Accepted: 12/14/2006] [Indexed: 11/28/2022]
Abstract
This paper focuses on the three areas in this field in which there have been advances in amino acid and organic acid metabolism. These are the description of glutamine synthetase deficiency, the elucidation of the mechanism of pyridoxine-dependent convulsions, and a hypothesis to explain the neurological complications of some organic acidaemias.
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Affiliation(s)
- J V Leonard
- Biochemistry, Endocrinology and Metabolism Unit, Institute of Child Health, University College London, London, UK.
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Rankin PM, Harrison S, Chong WK, Boyd S, Aylett SE. Pyridoxine-dependent seizures: a family phenotype that leads to severe cognitive deficits, regardless of treatment regime. Dev Med Child Neurol 2007; 49:300-5. [PMID: 17376142 DOI: 10.1111/j.1469-8749.2007.00300.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The neuropsychological and clinical histories of three male siblings affected by pyridoxine-dependent seizures with known homozygous antiquitin mutations are presented. Neuropsychological evaluation is reported from when the siblings were 11, 9, and 7 years of age. Two of the siblings had received early pyridoxine treatment (antenatal, 2-4 wks into pregnancy) and one had received late treatment (2mo postnatal). However, there was no differential effect on cognitive outcome, with all three siblings having moderate to severe learning disability. Unlike previously reported cases that received early postnatal treatment, none of the siblings had relatively preserved non-verbal cognitive skills. Equally, their intellectual performance over time did not increase above the 1st centile despite high maintenance doses of vitamin B6 (range 16-26 mg/kg/d), and mild sensory neuropathy was reported on nerve conduction studies. The findings in these siblings challenge assumptions that early and high dose pyridoxine treatment can benefit cognition in this population and suggest routine electromyography monitoring may be beneficial.
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Affiliation(s)
- Peter M Rankin
- Developmental Cognitive Neuroscience Unit, Institute of Child Health, University College London, UK.
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Plecko B, Paul K, Paschke E, Stoeckler-Ipsiroglu S, Struys E, Jakobs C, Hartmann H, Luecke T, di Capua M, Korenke C, Hikel C, Reutershahn E, Freilinger M, Baumeister F, Bosch F, Erwa W. Biochemical and molecular characterization of 18 patients with pyridoxine-dependent epilepsy and mutations of the antiquitin (ALDH7A1) gene. Hum Mutat 2007; 28:19-26. [PMID: 17068770 DOI: 10.1002/humu.20433] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Patients with pyridoxine dependent epilepsy (PDE) present with early-onset seizures resistant to common anticonvulsants. According to the benefit of pyridoxine (vitamin B(6)) and recurrence of seizures on pyridoxine withdrawal, patients so far have been classified as having definite, probable, or possible PDE. Recently, PDE has been shown to be caused by a defect of alpha-amino adipic semialdehyde (AASA) dehydrogenase (antiquitin) in the cerebral lysine degradation pathway. The accumulating compound piperideine-6-carboxylic acid (P6C) was shown to inactivate pyridoxalphosphate (PLP) by a Knoevenagel condensation. Pipecolic acid (PA) and AASA are markedly elevated in urine, plasma, and cerebrospinal fluid (CSF) and thus can be used as biomarkers of the disease. We have investigated 18 patients with neonatal seizure onset, who have been classified as having definite (11), probable (four), or possible (three) PDE. All patients had elevated PA and AASA in plasma (and urine) while on treatment with individual dosages of pyridoxine. Within this cohort, molecular analysis identified 10 novel mutations (six missense mutations, one nonsense mutation, two splice site mutations) within highly conserved regions of the antiquitin gene. Seven mutations were located in exonic sequences and two in introns 7 and 17. Furthermore, a novel deletion of exon 7 was identified. Two of the 36 alleles investigated require further investigation. A known mutation (p.Glu399Gln) was found with marked prevalence, accounting for 12 out of 36 alleles (33%) within our cohort. Pyridoxine withdrawal is no longer needed to establish the diagnosis of "definite" PDE. Administration of pyridoxine in PDE may not only correct secondary PLP deficiency, but may also lead to a reduction of AASA (and P6C) as presumably toxic compounds.
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Affiliation(s)
- Barbara Plecko
- Department of Pediatrics, Medical University Graz, Graz, Austria.
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Pearl PL, Gospe SM. Pyridoxal phosphate dependency, a newly recognized treatable catastrophic epileptic encephalopathy. J Inherit Metab Dis 2007; 30:2-4. [PMID: 19165905 DOI: 10.1007/s10545-008-9974-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Pearl PL, Hartka TR, Taylor J. Diagnosis and treatment of neurotransmitter disorders. Curr Treat Options Neurol 2006; 8:441-50. [PMID: 17032564 DOI: 10.1007/s11940-006-0033-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The neurotransmitter disorders represent an enigmatic and enlarging group of neurometabolic conditions caused by abnormal neurotransmitter metabolism or transport. A high index of clinical suspicion is important, given the availability of therapeutic strategies. This article covers disorders of monoamine (catecholamine and serotonin) synthesis, glycine catabolism, pyridoxine dependency, and gamma-aminobutyric acid (GABA) metabolism. The technological aspects of appropriate cerebrospinal fluid (CSF) collection, shipment, study, and interpretation merit special consideration. Diagnosis of disorders of monoamines requires analysis of CSF homovanillic acid, 5-hydroxyindoleacetic acid, ortho-methyldopa, BH4, and neopterin. The delineation of new disorders with important therapeutic implications, such as cerebral folate deficiency and PNPO deficiency, serves to highlight the value of measuring CSF neurotransmitter precursors and metabolites. The impressive responsiveness of Segawa fluctuating dystonia to levodopa is a hallmark feature of previously unrecognized neurologic morbidity becoming treatable at any age. Aromatic amino acid decarboxylase and tyrosine hydroxylase deficiency have more severe phenotypes and show variable responsiveness to levodopa. Glycine encephalopathy usually has a poor outcome; benzoate therapy may be helpful in less affected cases. Pyridoxine-dependent seizures are a refractory but treatable group of neonatal and infantile seizures; rare cases require pyridoxal-5-phosphate. Succinic semialdehyde dehydrogenase deficiency is relatively common in comparison to the remainder of this group of disorders. Treatment directed at the metabolic defect with vigabatrin has been disappointing, and multiple therapies are targeted toward specific but protean symptoms. Other disorders of GABA metabolism, as is true of the wide spectrum of neurotransmitter disorders, will require increasing use of CSF analysis for diagnosis, and ultimately, treatment.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Children’s National Medical Center, Washington, DC 20010, USA.
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27
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Abstract
The investigation of rare neurogenetic diseases is an example of how a translational science approach may lead to the delineation of complex genetic and biochemical pathways. Thisprocess comprises several intellectual stages. The first step involves the astute identification and clinical description of the unique phenotype, which may lead to obvious pathways or may reveal novel or unexpected mechanisms. As similar patients are identified, the establishment of databases detailing the clinical phenotype may serve to provide clues as to the genetic and biochemical characterization, and identification of the genetic mutation based on patient samples and animal or cellular models. Lastly, attempts to develop and apply therapies based on what has been learned about the biochemical and molecular bases of the disease enables intervention on the individual patient level. Several stages of discovery may overlap or be investigated simultaneously. As examples, this review discusses how this process of investigation has enabled progress in the delineation of several genetic and neurogenetic disorders, including Progeria syndrome, neurodegenerative diseases, muscular dystrophy, Rett syndrome and neurotransmitter disorders. This review attempts to summarize the transition from the bedside-to-bench-to-bedside as a model of bringing such discoveries into the clinical arena, and in doing so addresses the issues that may enhance, or complicate, such a path of discovery, as well as the impact such advances in genetics and genomics may have on the practice of clinical medicine and the role of the physician.
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Affiliation(s)
- Andrea Gropman
- Georgetown University, Department of Pediatrics, Washington, DC 20007, USA. Current address: Department of Neurology, Children’s National Medical Center, George Washington University School of Medicine, Washington, DC 20010, USA
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Abstract
Vitamin B6 is an important vitamin for normal brain function. The metabolism of dietary vitamin B6 to its active cofactor pyridoxal 5´-phosphate is described. The mechanism of action of pyridoxal 5´-phosphate is described, as are some important functions in the brain. The clinical features and biochemistry of three inborn errors of metabolism affecting brain pyridoxal 5´-phosphate concentrations are described, each of which cause early-onset epilepsy of variable severity. These are pyridoxine phosphate oxidase deficiency, hyperprolinemia Type 2 and pyridoxine-dependent epilepsy caused by antiquitin deficiency. Hypophosphatasia is also discussed briefly, as the epilepsy that can complicate this disorder appears to be due to pyridoxal phosphate deficiency. Lastly, the antiepileptic properties of pyridoxine and pyridoxal phosphate are discussed.
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Affiliation(s)
- Robert Surtees
- UCL Institute of Child Health, Neurosciences Unit, 30 Guilford Street, London, WC1N 1EH, UK
| | - Philippa Mills
- UCL Institute of Child Health, Biochemistry, Endocrinology & Metabolism Unit, 30 Guilford Street, London, WC1N 1EH, UK
| | - Peter Clayton
- UCL Institute of Child Health, Biochemistry, Endocrinology & Metabolism Units, 30 Guilford Street, London, WC1N 1EH, UK
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Clayton PT. B6-responsive disorders: a model of vitamin dependency. J Inherit Metab Dis 2006; 29:317-26. [PMID: 16763894 DOI: 10.1007/s10545-005-0243-2] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 02/09/2006] [Indexed: 10/24/2022]
Abstract
Pyridoxal phosphate is the cofactor for over 100 enzyme-catalysed reactions in the body, including many involved in the synthesis or catabolism of neurotransmitters. Inadequate levels of pyridoxal phosphate in the brain cause neurological dysfunction, particularly epilepsy. There are several different mechanisms that lead to an increased requirement for pyridoxine and/or pyridoxal phosphate. These include: (i) inborn errors affecting the pathways of B(6) vitamer metabolism; (ii) inborn errors that lead to accumulation of small molecules that react with pyridoxal phosphate and inactivate it; (iii) drugs that react with pyridoxal phosphate; (iv) coeliac disease, which is thought to lead to malabsorption of B(6) vitamers; (v) renal dialysis, which leads to increased losses of B(6) vitamers from the circulation; (vi) drugs that affect the metabolism of B(6) vitamers; and (vii) inborn errors affecting specific pyridoxal phosphate-dependent enzymes. The last show a very variable degree of pyridoxine responsiveness, from 90% in X-linked sideroblastic anaemia (delta-aminolevulinate synthase deficiency) through 50% in homocystinuria (cystathionine beta-synthase deficiency) to 5% in ornithinaemia with gyrate atrophy (ornithine delta-aminotransferase deficiency). The possible role of pyridoxal phosphate as a chaperone during folding of nascent enzymes is discussed. High-dose pyridoxine or pyridoxal phosphate may have deleterious side-effects (particularly peripheral neuropathy with pyridoxine) and this must be considered in treatment regimes. None the less, in some patients, particularly infants with intractable epilepsy, treatment with pyridoxine or pyridoxal phosphate can be life-saving, and in other infants with inborn errors of metabolism B(6) treatment can be extremely beneficial.
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Affiliation(s)
- Peter T Clayton
- Biochemistry, Endocrinology and Metabolism, Institute of Child Health, 30 Guilford St, London, WC1N 1 EH, UK.
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Gospe SM. Pyridoxine-dependent seizures: new genetic and biochemical clues to help with diagnosis and treatment. Curr Opin Neurol 2006; 19:148-53. [PMID: 16538088 DOI: 10.1097/01.wco.0000218230.81301.12] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW Pyridoxine dependency is an uncommon but important cause of intractable seizures presenting in infancy and early childhood. This paper discusses recent clinical, biochemical and genetic studies and how the findings should change our approach in evaluating young patients with antiepileptic drug-resistant seizures. RECENT FINDINGS Originally thought to be due to abnormal binding of pyridoxal phosphate to glutamic acid decarboxylase resulting in decreased gamma-aminobutyric acid, mutations in the gene encoding this enzyme have been ruled out. While linkage to 5q31 has been demonstrated, a disease-causing gene in that region has not been identified. Further haplotype analysis of six affected kindreds has demonstrated genetic heterogeneity for this rare disorder. Other studies demonstrate that some children with intractable seizures respond to pyridoxal phosphate rather than pyridoxine, including a rare form of neonatal epileptic encephalopathy shown to be due to mutations in the PNPO gene for pyridox(am)ine 5'-phosphate oxidase. While the biochemical explanation for this finding is not clear, elevated pipecolic acid levels may serve as a diagnostic marker for patients with pyridoxine-dependent seizures. SUMMARY The results of these studies should prompt clinicians to adopt new strategies for diagnosis and therapy for young patients with intractable seizures. Levels of both pipecolic acid and certain metabolites shown to be elevated in patients with PNPO mutations should be measured, and therapeutic trials of pyridoxal phosphate as well as pyridoxine should be considered early in the course of the management of infants and young children with intractable seizures.
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Affiliation(s)
- Sidney M Gospe
- Division of Pediatric Neurology, Departments of Neurology and Pediatrics, University of Washington, Seattle, WA 98105, USA.
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Mills PB, Struys E, Jakobs C, Plecko B, Baxter P, Baumgartner M, Willemsen MAAP, Omran H, Tacke U, Uhlenberg B, Weschke B, Clayton PT. Mutations in antiquitin in individuals with pyridoxine-dependent seizures. Nat Med 2006; 12:307-9. [PMID: 16491085 DOI: 10.1038/nm1366] [Citation(s) in RCA: 360] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Accepted: 01/10/2006] [Indexed: 11/09/2022]
Abstract
We show here that children with pyridoxine-dependent seizures (PDS) have mutations in the ALDH7A1 gene, which encodes antiquitin; these mutations abolish the activity of antiquitin as a delta1-piperideine-6-carboxylate (P6C)-alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase. The accumulating P6C inactivates pyridoxal 5'-phosphate (PLP) by forming a Knoevenagel condensation product. Measurement of urinary alpha-AASA provides a simple way of confirming the diagnosis of PDS and ALDH7A1 gene analysis provides a means for prenatal diagnosis.
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Affiliation(s)
- Philippa B Mills
- Institute of Child Health, University College London with Great Ormond Street Hospital for Children National Health Service Trust, 30 Guilford Street, London, UK
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Pearl PL, Capp PK, Novotny EJ, Gibson KM. Inherited disorders of neurotransmitters in children and adults. Clin Biochem 2005; 38:1051-8. [PMID: 16298354 DOI: 10.1016/j.clinbiochem.2005.09.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 09/16/2005] [Accepted: 09/21/2005] [Indexed: 11/24/2022]
Abstract
Inherited disorders of neurotransmitters are a group of neurometabolic syndromes attributable to a primary disturbance of neurotransmitter metabolism or transport. This is an enlarging group of recognized disorders requiring specialized diagnostic procedures for detection. This review considers clinical disorders of biopterin, catecholamines, serotonin, glycine, pyridoxine, and GABA metabolism. Newly described syndromes such as cerebral folate deficiency and pyridoxal-5-phosphate dependency are included. The disorders of the metabolic pathways of biopterin, catecholamines, and serotonin are linked due to their common synthetic components. Glycine encephalopathy represents an enlarging phenotype related to abnormalities of the glycine degradative cleavage system. Both pyridoxine and pyridoxal-5-phosphate dependency need to be considered in refractory neonatal seizures. The most common disorder of GABA metabolism is SSADH deficiency, which has a broad phenotype of mental retardation, epilepsy, ataxia, and hyporeflexia and which invokes the combined problems of elevated brain GABA and GHB.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Children's National Medical Center, George Washington University School of Medicine and Health Sciences, Washington, DC 22052, USA
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Bennett CL, Huynh HM, Chance PF, Glass IA, Gospe SM. Genetic heterogeneity for autosomal recessive pyridoxine-dependent seizures. Neurogenetics 2005; 6:143-9. [PMID: 16075246 DOI: 10.1007/s10048-005-0221-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Accepted: 05/16/2005] [Indexed: 10/25/2022]
Abstract
Pyridoxine-dependent seizure (PDS) is a rare autosomal recessive intractable seizure disorder only controlled by a daily supplementation of pharmacological doses of pyridoxine (Vitamin B6). Although glutamate decarboxylase utilizes pyridoxal phosphate as a cofactor during conversion of the excitatory amino acid, glutamate, to the inhibitory neurotransmitter, gamma-amino butyric acid (GABA), several studies have failed to demonstrate a linkage to either of the glutamate-decarboxylase-encoding genes (GAD1 and GAD2) and PDS excluding involvement of this functional candidate. However, in 2000, a locus for PDS was mapped to a 5 cM interval at chromosome 5q31 in four consanguineous and one multisib pedigree (Z(max)=8.43 at theta=0 for marker D5S2017) [Cormier-Daire et al. in Am J Hum Genet 67(4):991-993 2000]. We undertook molecular genetic studies of six nonconsanguineous North American families, using up to ten microsatellite markers to perform haplotype segregation analysis of the 5q31 locus. Assignment to the chromosome 5q PDS locus was excluded in one of the six North American PDS pedigrees, as chromosome 5q31 haplotypes were incompatible with linkage to this locus. The remaining five PDS pedigrees showed haplotype segregation consistent with linkage to 5q31, generating a maximum combined lod score of 1.87 (theta=0) at marker D5S2011. In this study, we establish genetic heterogeneity for PDS, catalog 21 genes within the originally defined PDS interval, and identify additional recombinations that indicate a higher priority interval, containing just 11 genes.
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Affiliation(s)
- C L Bennett
- Division of Genetics and Developmental Medicine, Department of Pediatrics, University of Washington and Children's Hospital and Regional Medical Center, Seattle, USA.
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Nicolai J. Pyridoxine-dependent seizures and microcephaly. Pediatr Neurol 2005; 33:75; author reply 75. [PMID: 15993328 DOI: 10.1016/j.pediatrneurol.2005.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Indexed: 11/16/2022]
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Wang HS, Kuo MF, Chou ML, Hung PC, Lin KL, Hsieh MY, Chang MY. Pyridoxal phosphate is better than pyridoxine for controlling idiopathic intractable epilepsy. Arch Dis Child 2005; 90:512-5. [PMID: 15851435 PMCID: PMC1720393 DOI: 10.1136/adc.2003.045963] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To study the difference between pyridoxine (PN) and its active form, pyridoxal phosphate, (PLP) in control of idiopathic intractable epilepsy in children. METHODS Among 574 children with active epilepsy, 94 (aged 8 months to 15 years) were diagnosed with idiopathic intractable epilepsy for more than six months. All received intravenous PLP 10 mg/kg, then 10 mg/kg/day in four divided doses. If seizures recurred within 24 hours, another dose of 40 mg/kg was given, followed by 50 mg/kg/day in four divided doses. For those patients whose seizures were totally controlled, PLP was replaced by the same dose of oral PN. If the seizure recurred, intravenous PLP was infused followed by oral PLP 50 mg/kg/day. RESULTS Fifty seven patients had generalised seizures (of whom 13 had infantile spasms) and 37 had focal seizure. Eleven had dramatic and sustained responses to PLP; of these, five also responded to PN. Within six months of treatment with PLP or PN, five of the 11 patients were seizure free and had their previous antiepileptic medicine tapered off gradually. Two were controlled with pyridoxine and the other three needed PLP to maintain seizure freedom. The remaining six responders needed PLP exclusively for seizure control. Six of the 11 responders to PLP had infantile spasms (46%); four of them needed PLP exclusively. The other five responders were in the remaining 81 patients with other seizure type. CONCLUSIONS PLP could replace PN in the treatment of intractable childhood epilepsy, particularly in the treatment of infantile spasms.
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Affiliation(s)
- H-S Wang
- Division of Pediatric Neurology, Chang Gung Children's Hospital, and Medical College of Chang Gung University, Taoyuan, Taiwan.
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36
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Lynex CN, Carr IM, Leek JP, Achuthan R, Mitchell S, Maher ER, Woods CG, Bonthon DT, Markham AF. Homozygosity for a missense mutation in the 67 kDa isoform of glutamate decarboxylase in a family with autosomal recessive spastic cerebral palsy: parallels with Stiff-Person Syndrome and other movement disorders. BMC Neurol 2004; 4:20. [PMID: 15571623 PMCID: PMC544830 DOI: 10.1186/1471-2377-4-20] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 11/30/2004] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Cerebral palsy (CP) is an heterogeneous group of neurological disorders of movement and/or posture, with an estimated incidence of 1 in 1000 live births. Non-progressive forms of symmetrical, spastic CP have been identified, which show a Mendelian autosomal recessive pattern of inheritance. We recently described the mapping of a recessive spastic CP locus to a 5 cM chromosomal region located at 2q24-31.1, in rare consanguineous families. METHODS Here we present data that refine this locus to a 0.5 cM region, flanked by the microsatellite markers D2S2345 and D2S326. The minimal region contains the candidate gene GAD1, which encodes a glutamate decarboxylase isoform (GAD67), involved in conversion of the amino acid and excitatory neurotransmitter glutamate to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). RESULTS A novel amino acid mis-sense mutation in GAD67 was detected, which segregated with CP in affected individuals. CONCLUSIONS This result is interesting because auto-antibodies to GAD67 and the more widely studied GAD65 homologue encoded by the GAD2 gene, are described in patients with Stiff-Person Syndrome (SPS), epilepsy, cerebellar ataxia and Batten disease. Further investigation seems merited of the possibility that variation in the GAD1 sequence, potentially affecting glutamate/GABA ratios, may underlie this form of spastic CP, given the presence of anti-GAD antibodies in SPS and the recognised excitotoxicity of glutamate in various contexts.
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Affiliation(s)
- Clare N Lynex
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
| | - Ian M Carr
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
| | - Jack P Leek
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
| | - Rajgopal Achuthan
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
| | - Simon Mitchell
- Neonatal Medical Unit, St Mary's Hospital, Manchester, UK
| | - Eamonn R Maher
- Department of Paediatrics and Child Health, Section of Medical and Molecular Genetics, The Medical School, University of Birmingham, Birmingham, UK
| | - C Geoffrey Woods
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
| | - David T Bonthon
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
| | - Alex F Markham
- Molecular Medicine Unit, University of Leeds, Clinical Sciences Building, St James's University Hospital, Leeds, UK
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Gachon F, Fonjallaz P, Damiola F, Gos P, Kodama T, Zakany J, Duboule D, Petit B, Tafti M, Schibler U. The loss of circadian PAR bZip transcription factors results in epilepsy. Genes Dev 2004; 18:1397-412. [PMID: 15175240 PMCID: PMC423191 DOI: 10.1101/gad.301404] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
DBP (albumin D-site-binding protein), HLF (hepatic leukemia factor), and TEF (thyrotroph embryonic factor) are the three members of the PAR bZip (proline and acidic amino acid-rich basic leucine zipper) transcription factor family. All three of these transcriptional regulatory proteins accumulate with robust circadian rhythms in tissues with high amplitudes of clock gene expression, such as the suprachiasmatic nucleus (SCN) and the liver. However, they are expressed at nearly invariable levels in most brain regions, in which clock gene expression only cycles with low amplitude. Here we show that mice deficient for all three PAR bZip proteins are highly susceptible to generalized spontaneous and audiogenic epilepsies that frequently are lethal. Transcriptome profiling revealed pyridoxal kinase (Pdxk) as a target gene of PAR bZip proteins in both liver and brain. Pyridoxal kinase converts vitamin B6 derivatives into pyridoxal phosphate (PLP), the coenzyme of many enzymes involved in amino acid and neurotransmitter metabolism. PAR bZip-deficient mice show decreased brain levels of PLP, serotonin, and dopamine, and such changes have previously been reported to cause epilepsies in other systems. Hence, the expression of some clock-controlled genes, such as Pdxk, may have to remain within narrow limits in the brain. This could explain why the circadian oscillator has evolved to generate only low-amplitude cycles in most brain regions.
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Affiliation(s)
- Frédéric Gachon
- Department of Molecular Biology, National Center of Competence Research Frontiers in Genetics, Sciences III, University of Geneva, CH-1211 Geneva 4, Switzerland
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Schulze-Bonhage A, Kurthen M, Walger P, Elger CE. Pharmacorefractory status epilepticus due to low vitamin B6 levels during pregnancy. Epilepsia 2004; 45:81-4. [PMID: 14692912 DOI: 10.1111/j.0013-9580.2004.00703.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a patient with pyridoxine-dependent epileptic seizures during early childhood. She had been completely seizure free for 23 years until she became pregnant. During the week 14 of her pregnancy, status epilepticus developed and was refractory to antiepileptic drugs but responded to intravenous administration of vitamin B6. Vitamin B6 levels were found to be decreased during pregnancy, although the patient reported continued and regular oral supplementation. Possible reasons for decreased vitamin B6 levels leading to status epilepticus are discussed.
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Baxter P. Pyridoxine-dependent seizures: a clinical and biochemical conundrum. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1647:36-41. [PMID: 12686105 DOI: 10.1016/s1570-9639(03)00045-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pyridoxine-dependent seizures have been recognised for 40 years, but the clinical and biochemical features are still not understood. It is a rare recessively inherited condition where classically a baby starts convulsing in utero and continues to do so after birth, until given pyridoxine. Many of these early onset cases also have an acute encephalopathy and other clinical features. Late onset cases are now recognised with a less severe form of the condition. Seizures can break through with intercurrent illness but otherwise remain controlled on pharmacologic doses of pyridoxine. The long-term outcome is affected by several factors including whether onset is early or late and how soon pyridoxine is given. Biochemical studies have been sparse, on very small numbers. There does not appear to be any defect in the uptake or metabolism of pyridoxine or pyridoxal phosphate (PLP). For a long time glutamic acid decarboxylase (GAD), a pyridoxal-dependent enzyme, has been suspected to be the abnormal gene product, but glutamate and gamma-aminobutyric acid (GABA) studies on the cerebrospinal fluid (CSF) have been contradictory and recent genetic studies have not found any linkage to the two brain isoforms. A recent report describes raised pipecolic acid levels in patients but how this ties in is unexplained.
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Affiliation(s)
- Peter Baxter
- Ryegate Centre Paediatric Neurology, Sheffield Childrens Hospital, Tapton Crescent Road, Sheffield S10 5DD, UK.
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40
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Mueller S, Wieser H. Reply to Letter to the Editor. Brain Res Bull 2002. [DOI: 10.1016/s0361-9230(02)00876-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kelly A, Stanley CA. Disorders of glutamate metabolism. MENTAL RETARDATION AND DEVELOPMENTAL DISABILITIES RESEARCH REVIEWS 2002; 7:287-95. [PMID: 11754524 DOI: 10.1002/mrdd.1040] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The significant role the amino acid glutamate assumes in a number of fundamental metabolic pathways is becoming better understood. As a central junction for interchange of amino nitrogen, glutamate facilitates both amino acid synthesis and degradation. In the liver, glutamate is the terminus for release of ammonia from amino acids, and the intrahepatic concentration of glutamate modulates the rate of ammonia detoxification into urea. In pancreatic beta-cells, oxidation of glutamate mediates amino acid-stimulated insulin secretion. In the central nervous system, glutamate serves as an excitatory neurotransmittor. Glutamate is also the precursor of the inhibitory neurotransmittor GABA, as well as glutamine, a potential mediator of hyperammonemic neurotoxicity. The recent identification of a novel form of congenital hyperinsulinism associated with asymptomatic hyperammonemia assigns glutamate oxidation by glutamate dehydrogenase a more important role than previously recognized in beta-cell insulin secretion and hepatic and CNS ammonia detoxification. Disruptions of glutamate metabolism have been implicated in other clinical disorders, such as pyridoxine-dependent seizures, confirming the importance of intact glutamate metabolism. This article will review glutamate metabolism and clinical disorders associated with disrupted glutamate metabolism.
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Affiliation(s)
- A Kelly
- Division of Endocrinology, Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania Medical School, 19104, USA
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Abstract
Pyridoxine-dependent seizures, although a rare clinical entity, have been recognized as an etiology of intractable seizures in neonates and infants for more than 45 years. Recent research has focused on the molecular and neurochemical aspects of this disorder, as well as the optimal treatment of the condition. This review discusses the clinical features and management of patients with pyridoxine-dependent seizures together with a new hypothesis suggesting that an abnormality of pyridoxine transport may underlie the pathophysiology of this autosomal-recessive disorder.
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Affiliation(s)
- Sidney M Gospe
- Division of Pediatric Neurology, Department of Neurology, University of Washington, and Children's Hospital and Regional Medical Center, Seattle, WA 98105, USA
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Abstract
Epilepsy may be acquired or inherited. At least one half of epilepsy is genetic in origin; this figure is likely higher in children regardless of whether seizures are generalized or partial. Inherited epilepsies are classified as benign, cryptogenic, or symptomatic depending on associated clinical, electrographic, and neuroimaging features. To date, genetic mutations in the idiopathic inherited epilepsies affect channel function within the central nervous system; genes underlying symptomatic epilepsies are more heterogeneous. Accurate diagnosis of an inherited epilepsy syndrome provides useful prognostic information; it also may help guide diagnostic evaluation, including request for specific gene testing. In the near future, the relationship between genetic defect and response to specific anticonvulsants may also be better defined.
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Affiliation(s)
- L E Walsh
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis 46202, USA
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