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Feng Y, Zhang C, Wei Z, Li G, Gan Y, Liu C, Deng Y. Gene variations of glutamate metabolism pathway and epilepsy. ACTA EPILEPTOLOGICA 2022. [DOI: 10.1186/s42494-022-00103-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Epilepsy is a paroxysmal disorder of the brain, caused by an imbalance of neuronal excitation and inhibition. Glutamate is the most important excitatory neurotransmitter in the brain and plays an important role in epileptogenesis. Mutations in genes at any step/component of the glutamate metabolic pathway may lead to the development of epilepsy or epileptic encephalopathy.
Methods
Clinical history of 3 epilepsy patients with genetic variations of the glutamate metabolism pathway was collected. Electroencephalogram recording and magnetic resonance imaging were performed in each patient. We also reviewed recent literature for a variety of the genetic variations involved in epilepsy.
Results
Case 1 was a SLC1A2 mutation-carrier diagnosed with developmental and epileptic encephalopathy (DEE) 41, whose seizures decreased after start of the ketogenic diet. Case 2 carried a GRIN2A gene mutation and was seizure-free for three years after taking levetiracetam and vitamin B6. Case 3 was a GRIN2B mutation-carrier diagnosed with DEE 27, who seizures diminished after taking oxcarbazepine.
Conclusions
Preclinical and clinical evidence supports the therapeutic potential of glutamatergic signaling-targeting treatments for epilepsy. More studies are needed to discover novel DEE-related genetic mutations in the glutamate metabolic pathway.
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Rosenfeld E, Nanga RPR, Lucas A, Revell AY, Thomas A, Thomas NH, Roalf DR, Shinohara RT, Reddy R, Davis KA, De León DD. Characterizing the neurological phenotype of the hyperinsulinism hyperammonemia syndrome. Orphanet J Rare Dis 2022; 17:248. [PMID: 35752848 PMCID: PMC9233810 DOI: 10.1186/s13023-022-02398-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/11/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hyperinsulinism hyperammonemia (HI/HA) syndrome is caused by activating mutations in GLUD1, encoding glutamate dehydrogenase (GDH). Atypical absence seizures and neuropsychological disorders occur at high rates in this form of hyperinsulinism. Dysregulated central nervous system (CNS) glutamate balance, due to GDH overactivity in the brain, has been hypothesized to play a role. This study aimed to describe the neurologic phenotype in HI/HA syndrome and investigate CNS glutamate levels using glutamate weighted chemical exchange saturation transfer magnetic resonance imaging (GluCEST MRI). In this cross-sectional study, 12 subjects with HI/HA syndrome had plasma ammonia measurement, self- or parent-completed neurocognitive assessments, electroencephalogram (EEG), and GluCEST MRI at 7 T performed. GluCEST MRI measures were compared to a historic reference population of 10 healthy adults. RESULTS Subjects were five males and seven females with median age of 25.5 years. Seventy-five percent of subjects reported a history of neurodevelopmental problems and 42% had neurocognitive assessment scores outside the normal range. Fifty percent had interictal EEG findings of generalized, irregular spike and wave discharges. Higher variability in hippocampal GluCEST asymmetry (p = 0.002), and in peak hippocampal GluCEST values (p = 0.008), was observed in HI/HA subjects (n = 9 with interpretable MRI) compared to the healthy reference population (n = 10). CONCLUSIONS The high prevalence of abnormal neurocognitive assessment scores and interictal EEG findings observed highlights the importance of longitudinal neuropsychological assessment for individuals with HI/HA syndrome. Our findings demonstrate the potential application of GluCEST to investigate persistent knowledge gaps in the mechanisms underlying the unique neurophenotype of this disorder.
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Affiliation(s)
- Elizabeth Rosenfeld
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, Philadelphia, PA, 19140, USA. .,Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Ravi Prakash Reddy Nanga
- Center for Advanced Metabolic Imaging in Precision Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Alfredo Lucas
- Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew Y Revell
- Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - Allison Thomas
- Behavioral Neuroscience Core, Center for Human Phenomic Science, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Nina H Thomas
- Behavioral Neuroscience Core, Center for Human Phenomic Science, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Child and Adolescent Psychiatry and Behavioral Sciences, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - David R Roalf
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Russel T Shinohara
- Penn Statistics in Imaging and Visualization Center, Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.,Center for Biomedical Image Computing and Analytics, Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn A Davis
- Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Diva D De León
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, Philadelphia, PA, 19140, USA.,Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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3
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Mathioudakis L, Bourbouli M, Daklada E, Kargatzi S, Michaelidou K, Zaganas I. Localization of Human Glutamate Dehydrogenases Provides Insights into Their Metabolic Role and Their Involvement in Disease Processes. Neurochem Res 2018; 44:170-187. [PMID: 29943084 DOI: 10.1007/s11064-018-2575-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/11/2018] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
Abstract
Glutamate dehydrogenase (GDH) catalyzes the reversible deamination of L-glutamate to α-ketoglutarate and ammonia. In mammals, GDH contributes to important processes such as amino acid and carbohydrate metabolism, energy production, ammonia management, neurotransmitter recycling and insulin secretion. In humans, two isoforms of GDH are found, namely hGDH1 and hGDH2, with the former being ubiquitously expressed and the latter found mainly in brain, testis and kidney. These two iso-enzymes display highly divergent allosteric properties, especially concerning their basal activity, ADP activation and GTP inhibition. On the other hand, both enzymes are thought to predominantly localize in the mitochondrial matrix, even though alternative localizations have been proposed. To further study the subcellular localization of the two human iso-enzymes, we created HEK293 cell lines stably over-expressing hGDH1 and hGDH2. In these cell lines, immunofluorescence and enzymatic analyses verified the overexpression of both hGDH1 and hGDH2 iso-enzymes, whereas subcellular fractionation followed by immunoblotting showed their predominantly mitochondrial localization. Given that previous studies have only indirectly compared the subcellular localization of the two iso-enzymes, we co-expressed them tagged with different fluorescent dyes (green and red fluorescent protein for hGDH1 and hGDH2, respectively) and found them to co-localize. Despite the wealth of information related to the functional properties of hGDH1 and hGDH2 and the availability of the hGDH1 structure, there is still an ongoing debate concerning their metabolic role and their involvement in disease processes. Data on the localization of hGDHs, as the ones presented here, could contribute to better understanding of the function of these important human enzymes.
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Affiliation(s)
- Lambros Mathioudakis
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Mara Bourbouli
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Elisavet Daklada
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Sofia Kargatzi
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Kleita Michaelidou
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Ioannis Zaganas
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece. .,Department of Neurology, University Hospital of Heraklion, Heraklion, Crete, Greece.
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4
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Ninković D, Sarnavka V, Bašnec A, Ćuk M, Ramadža DP, Fumić K, Kušec V, Santer R, Barić I. Hyperinsulinism-hyperammonemia syndrome: a de novo mutation of the GLUD1 gene in twins and a review of the literature. J Pediatr Endocrinol Metab 2016; 29:1083-8. [PMID: 27383869 DOI: 10.1515/jpem-2016-0086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 05/09/2016] [Indexed: 01/25/2023]
Abstract
Hyperinsulinism-hyperammonemia (HI/HA) syndrome is a rare autosomal dominant disease characterized by recurrent hypoglycemia and persistent mild elevation of plasma ammonia. HI/HA syndrome is one of the more common forms of congenital hyperinsulinism (CHI), caused by activating mutations within the GLUD1 gene that encodes the mitochondrial enzyme glutamate dehydrogenase (GDH). We report here on monozygotic twin girls presented with fasting- and protein-induced hypoglycemia and mild persistent hyperammonemia. Genetic analysis revealed that both girls were heterozygous for a novel missense mutation within exon 11 [c.1499A>T, p.(R443W)] of the GLUD1 gene. Despite early treatment with diazoxide and a low protein diet, they both developed non-hypoglycemic seizures in early childhood followed by cognitive impairment. In addition to their clinical course, a review of the literature on HI/HA syndrome is provided.
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Sarajlija A, Milenkovic T, Djordjevic M, Mitrovic K, Todorovic S, Kecman B, Hussain K. Early Presentation of Hyperinsulinism/Hyperammonemia Syndrome in Three Serbian Patients. J Clin Res Pediatr Endocrinol 2016; 8:228-31. [PMID: 26759084 PMCID: PMC5096481 DOI: 10.4274/jcrpe.2436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Hyperinsulinism/hyperammonemia (HI/HA) syndrome is considered as the second most common type of hereditary HI. Correlation of genotype and phenotype in HI/HA syndrome has been described in several studies. We present three Serbian patients with HI/HA syndrome with emphasis on a possible correlation between genotype and clinical manifestations. Patient 1 was heterozygous for a de novo mutation p.S445L in the GLUD1 gene, while patients 2 and 3 (son and mother) both carry the p.R221C mutation. Early onset of hypoglycaemia with generalized seizures was recorded in infancy in all three patients. The two male patients had mild developmental delay, while the female patient presented with epilepsy. Analysis of Serbian patients with HI/HA syndrome confirms the association of p.S445L and p.R221C mutations with hypoglycaemic seizures noted within the first three months of life and with subsequent risk for cognitive impairment and/or epilepsy.
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Affiliation(s)
- Adrijan Sarajlija
- Mother and Child Health Care Institute of Serbia "Dr Vukan Cupic", Department of Metabolism and Clinical Genetics, Belgrade, Serbia E-mail:
| | - Tatjana Milenkovic
- Mother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Department of Endocrinology, Belgrade, Serbia
| | - Maja Djordjevic
- Mother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Department of Metabolism and Clinical Genetics, Belgrade, Serbia
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University of Belgrade Faculty of Medicine, Belgrade, Serbia
| | - Katarina Mitrovic
- Mother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Department of Endocrinology, Belgrade, Serbia
| | - Sladjana Todorovic
- Mother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Department of Endocrinology, Belgrade, Serbia
| | - Bozica Kecman
- Mother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Department of Metabolism and Clinical Genetics, Belgrade, Serbia
| | - Khalid Hussain
- Great Ormond Street Hospital for Children NHS Trust, Department of Pediatric Endocrinology, London, United Kingdom
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University College London, Institute of Child Health, London, United Kingdom
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Zsurka G, Kunz WS. Mitochondrial dysfunction and seizures: the neuronal energy crisis. Lancet Neurol 2015; 14:956-66. [PMID: 26293567 DOI: 10.1016/s1474-4422(15)00148-9] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/19/2015] [Accepted: 06/24/2015] [Indexed: 12/21/2022]
Abstract
Seizures are often the key manifestation of neurological diseases caused by pathogenic mutations in 169 of the genes that have so far been identified to affect mitochondrial function. Mitochondria are the main producers of ATP needed for normal electrical activities of neurons and synaptic transmission. Additionally, they have a central role in neurotransmitter synthesis, calcium homoeostasis, redox signalling, production and modulation of reactive oxygen species, and neuronal death. Hypotheses link mitochondrial failure to seizure generation through changes in calcium homoeostasis, oxidation of ion channels and neurotransmitter transporters by reactive oxygen species, a decrease in neuronal plasma membrane potential, and reduced network inhibition due to interneuronal dysfunction. Seizures, irrespective of their origin, represent an excessive acute energy demand in the brain. Accordingly, secondary mitochondrial dysfunction has been described in various epileptic disorders, including disorders that are mainly of non-mitochondrial origin. An understanding of the reciprocal relation between mitochondrial dysfunction and epilepsy is crucial to select appropriate anticonvulsant treatment and has the potential to open up new therapeutic approaches in the subset of epileptic disorders caused by mitochondrial dysfunction.
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Affiliation(s)
- Gábor Zsurka
- Division of Neurochemistry, Department of Epileptology, and Life & Brain Center, University of Bonn, Bonn, Germany
| | - Wolfram S Kunz
- Division of Neurochemistry, Department of Epileptology, and Life & Brain Center, University of Bonn, Bonn, Germany.
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Ng YT. The hitchhiker's guide to the role of (transient) hypoglycemia in refractory seizures and epilepsy. Pediatr Neurol 2012; 47:123-4. [PMID: 22759689 DOI: 10.1016/j.pediatrneurol.2012.04.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 04/19/2012] [Indexed: 11/17/2022]
Abstract
Hypoglycemia and hypoglycorrhachia, although they are uncommon causes of refractory seizures and epilepsy, should always be considered because they are potentially treatable conditions. A high index of suspicion and low threshold for testing recurrent blood and at least one cerebrospinal fluid glucose level are required. Jeavons syndrome and other refractory cryptogenic/idiopathic epilepsies may involve symptomatic etiologies, including hyperinsulinism, GLUT1 deficiency, and other metabolic disorders.
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Affiliation(s)
- Yu-Tze Ng
- Division of Child Neurology, College of Medicine, University of Oklahoma, Oklahoma City, Oklahoma 73104, USA.
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