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Mastrangelo M, Manti F, Ricciardi G, Cinnante EMC, Cameli N, Beatrice A, Tolve M, Pisani F. The diagnostic and prognostic role of cerebrospinal fluid biomarkers in glucose transporter 1 deficiency: a systematic review. Eur J Pediatr 2024; 183:3665-3678. [PMID: 38954008 PMCID: PMC11322378 DOI: 10.1007/s00431-024-05657-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024]
Abstract
The purpose of this study is to investigate the diagnostic and prognostic role of cerebrospinal fluid (CSF) biomarkers in the diagnostic work-up of glucose transporter 1 (GLUT1) deficiency. Reported here is a systematic review according to PRISMA guidelines collecting clinical and biochemical data about all published patients who underwent CSF analysis. Clinical phenotypes were compared between groups defined by the levels of CSF glucose (≤ 2.2 mmol/L versus > 2.2 mmol/L), CSF/blood glucose ratio (≤ 0.45 versus > 0.45), and CSF lactate (≤ 1 mmol/L versus > 1 mmol/L). Five hundred sixty-two patients fulfilled the inclusion criteria with a mean age at the diagnosis of 8.6 ± 6.7 years. Patients with CSF glucose ≤ 2.2 mmol/L and CSF/blood glucose ratio ≤ 0.45 presented with an earlier onset of symptoms (16.4 ± 22.0 versus 54.4 ± 45.9 months, p < 0.01; 15.7 ± 23.8 versus 40.9 ± 38.0 months, p < 0.01) and received an earlier molecular genetic confirmation (92.1 ± 72.8 versus 157.1 ± 106.2 months, p < 0.01). CSF glucose ≤ 2.2 mmol/L was consistently associated with response to ketogenic diet (p = 0.018) and antiseizure medications (p = 0.025). CSF/blood glucose ratio ≤ 0.45 was significantly associated with absence seizures (p = 0.048), paroxysmal exercise-induced dyskinesia (p = 0.046), and intellectual disability (p = 0.016) while CSF lactate > 1 mmol/L was associated with a response to antiseizure medications (p = 0.026) but not to ketogenic diet.Conclusions:This systematic review supported the diagnostic usefulness of lumbar puncture for the early identification of patients with GLUT1 deficiency responsive to treatments especially if they present with co-occurring epilepsy, movement, and neurodevelopmental disorders. What is Known: • Phenotypes of GLUT1 deficiency syndrome range between early epileptic and developmental encephalopathy to paroxysmal movement disorders and developmental impairment What is New: • CSF blood/glucose ratio may predict better than CSF glucose the diagnosis in children presenting with early onset absences • CSF blood/glucose ratio may predict better than CSF glucose the diagnosis in children presenting with paroxysmal exercise induced dyskinesia and intellectual disability. • CSF glucose may predict better than CSF blood/glucose and lactate the response to ketogenic diet and antiseizure medications.
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Affiliation(s)
- Mario Mastrangelo
- Woman/Child Health and Urological Sciences Department, Sapienza University of Rome, Via dei Sabelli 108, 00185, Rome, Italy.
- Unit of Child Neurology and Psychiatry, Department of Neuroscience/Mental Health, Azienda Ospedaliero Universitaria Policlinico Umberto, Rome, Italy.
| | - Filippo Manti
- Unit of Child Neurology and Psychiatry, Department of Neuroscience/Mental Health, Azienda Ospedaliero Universitaria Policlinico Umberto, Rome, Italy
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | | | | | - Noemi Cameli
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | | | - Manuela Tolve
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria Policlinico Umberto I, Rome, Italy
| | - Francesco Pisani
- Unit of Child Neurology and Psychiatry, Department of Neuroscience/Mental Health, Azienda Ospedaliero Universitaria Policlinico Umberto, Rome, Italy
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
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2
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Giugno A, Falcone E, Fortunato F, Sammarra I, Procopio R, Gagliardi M, Bauleo A, de Stefano L, Martino I, Gambardella A. Glucose transporter-1 deficiency syndrome with extreme phenotypic variability in a five-generation family carrying a novel SLC2A1 variant. Eur J Neurol 2024; 31:e16325. [PMID: 38803061 PMCID: PMC11235872 DOI: 10.1111/ene.16325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/10/2024] [Accepted: 04/16/2024] [Indexed: 05/29/2024]
Abstract
BACKGROUND AND PURPOSE Glucose transporter-1 (GLUT1) deficiency syndrome (GLUT1-DS) is a metabolic disorder due to reduced expression of GLUT1, a glucose transporter of the central nervous system. GLUT1-DS is caused by heterozygous SLC2A1 variants that mostly arise de novo. Here, we report a large family with heterogeneous phenotypes related to a novel SLC2A1 variant. METHODS We present clinical and genetic features of a five-generation family with GLUT1-DS. RESULTS The 14 (nine living) affected members had heterogeneous phenotypes, including seizures (11/14), behavioral disturbances (5/14), mild intellectual disability (3/14), and/or gait disabilities (2/14). Brain magnetic resonance imaging revealed hippocampal sclerosis in the 8-year-old proband, who also had drug-responsive absences associated with attention-deficit/hyperactivity disorder. His 52-year-old father, who had focal epilepsy since childhood, developed paraparesis related to a reversible myelitis associated with hypoglycorrhachia. Molecular study detected a novel heterozygous missense variant (c.446C>T) in exon 4 of SLC2A1 (NM: 006516.2) that cosegregated with the illness. This variant causes an amino acid replacement (p.Pro149Leu) at the fourth transmembrane segment of GLUT1, an important domain located at its catalytic core. CONCLUSIONS Our study illustrates the extremely heterogenous phenotypes in familial GLUT1-DS, ranging from milder classic phenotypes to more subtle neurological disorder including paraparesis. This novel SLC2A1 variant (c.446C>T) provides new insight into the pathophysiology of GLUT1-DS.
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Affiliation(s)
- Alessia Giugno
- Department of Medical and Surgical Sciences, Institute of NeurologyUniversity Magna GræciaCatanzaroItaly
| | - Elena Falcone
- BIOGENET–Medical and Forensic Genetics LaboratoryCosenzaItaly
| | - Francesco Fortunato
- Department of Medical and Surgical Sciences, Institute of NeurologyUniversity Magna GræciaCatanzaroItaly
| | - Ilaria Sammarra
- Department of Medical and Surgical Sciences, Institute of NeurologyUniversity Magna GræciaCatanzaroItaly
| | - Radha Procopio
- Department of Medical and Surgical Sciences, Neuroscience Research CenterMagna Graecia UniversityCatanzaroItaly
| | - Monica Gagliardi
- Department of Medical and Surgical Sciences, Neuroscience Research CenterMagna Graecia UniversityCatanzaroItaly
| | - Alessia Bauleo
- BIOGENET–Medical and Forensic Genetics LaboratoryCosenzaItaly
| | | | - Iolanda Martino
- Department of Medical and Surgical Sciences, Institute of NeurologyUniversity Magna GræciaCatanzaroItaly
| | - Antonio Gambardella
- Department of Medical and Surgical Sciences, Institute of NeurologyUniversity Magna GræciaCatanzaroItaly
- Department of Medical and Surgical Sciences, Neuroscience Research CenterMagna Graecia UniversityCatanzaroItaly
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3
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Gan Y, Wei Z, Liu C, Li G, Feng Y, Deng Y. Solute carrier transporter disease and developmental and epileptic encephalopathy. Front Neurol 2022; 13:1013903. [PMID: 36419532 PMCID: PMC9676364 DOI: 10.3389/fneur.2022.1013903] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 09/07/2022] [Indexed: 09/14/2023] Open
Abstract
The International League Against Epilepsy officially revised its classification in 2017, which amended "epileptic encephalopathy" to "developmental and epileptic encephalopathy". With the development of genetic testing technology, an increasing number of genes that cause developmental and epileptic encephalopathies are being identified. Among these, solute transporter dysfunction is part of the etiology of developmental and epileptic encephalopathies. Solute carrier transporters play an essential physiological function in the human body, and their dysfunction is associated with various human diseases. Therefore, in-depth studies of developmental and epileptic encephalopathies caused by solute carrier transporter dysfunction can help develop new therapeutic modalities to facilitate the treatment of refractory epilepsy and improve patient prognosis. In this article, the concept of transporter protein disorders is first proposed, and nine developmental and epileptic encephalopathies caused by solute carrier transporter dysfunction are described in detail in terms of pathogenesis, clinical manifestations, ancillary tests, and precise treatment to provide ideas for the precise treatment of epilepsy.
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Affiliation(s)
- Yajing Gan
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Zihan Wei
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Chao Liu
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Guoyan Li
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yan Feng
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yanchun Deng
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an, China
- Xijing Institute of Epilepsy and Encephalopathy, Xi'an, China
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4
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Mauri A, Duse A, Palm G, Previtali R, Bova SM, Olivotto S, Benedetti S, Coscia F, Veggiotti P, Cereda C. Molecular Genetics of GLUT1DS Italian Pediatric Cohort: 10 Novel Disease-Related Variants and Structural Analysis. Int J Mol Sci 2022; 23:ijms232113560. [PMID: 36362347 PMCID: PMC9654628 DOI: 10.3390/ijms232113560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/26/2022] [Accepted: 10/29/2022] [Indexed: 11/09/2022] Open
Abstract
GLUT1 deficiency syndrome (GLUT1DS1; OMIM #606777) is a rare genetic metabolic disease, characterized by infantile-onset epileptic encephalopathy, global developmental delay, progressive microcephaly, and movement disorders (e.g., spasticity and dystonia). It is caused by heterozygous mutations in the SLC2A1 gene, which encodes the GLUT1 protein, a glucose transporter across the blood-brain barrier (BBB). Most commonly, these variants arise de novo resulting in sporadic cases, although several familial cases with AD inheritance pattern have been described. Twenty-seven Italian pediatric patients, clinically suspect of GLUT1DS from both sporadic and familial cases, have been enrolled. We detected by trios sequencing analysis 25 different variants causing GLUT1DS. Of these, 40% of the identified variants (10 out of 25) had never been reported before, including missense, frameshift, and splice site variants. Their structural mapping on the X-ray structure of GLUT1 strongly suggested the potential pathogenic effects of these novel disease-related mutations, broadening the genotypic spectrum heterogeneity found in the SLC2A1 gene. Moreover, 24% is located in a vulnerable region of the GLUT1 protein that involves transmembrane 4 and 5 helices encoded by exon 4, confirming a mutational hotspot in the SLC2A1 gene. Lastly, we investigated possible correlations between mutation type and clinical and biochemical data observed in our GLUT1DS cohort, revealing that splice site and frameshift variants are related to a more severe phenotype and low CSF parameters.
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Affiliation(s)
- Alessia Mauri
- Department of Biomedical and Clinical Sciences, University of Milan, 20157 Milan, Italy
- Newborn Screening and Genetic Metabolic Diseases Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
| | - Alessandra Duse
- Pediatric Neurology Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
| | - Giacomo Palm
- Structural Biology Center, Human Technopole, 20157 Milan, Italy
| | - Roberto Previtali
- Pediatric Neurology Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
| | | | - Sara Olivotto
- Pediatric Neurology Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
| | - Sara Benedetti
- Newborn Screening and Genetic Metabolic Diseases Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
| | | | - Pierangelo Veggiotti
- Department of Biomedical and Clinical Sciences, University of Milan, 20157 Milan, Italy
- Pediatric Neurology Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
| | - Cristina Cereda
- Newborn Screening and Genetic Metabolic Diseases Unit, V. Buzzi Children’s Hospital, 20154 Milan, Italy
- Correspondence:
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5
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Wortmann SB, Oud MM, Alders M, Coene KLM, van der Crabben SN, Feichtinger RG, Garanto A, Hoischen A, Langeveld M, Lefeber D, Mayr JA, Ockeloen CW, Prokisch H, Rodenburg R, Waterham HR, Wevers RA, van de Warrenburg BPC, Willemsen MAAP, Wolf NI, Vissers LELM, van Karnebeek CDM. How to proceed after "negative" exome: A review on genetic diagnostics, limitations, challenges, and emerging new multiomics techniques. J Inherit Metab Dis 2022; 45:663-681. [PMID: 35506430 PMCID: PMC9539960 DOI: 10.1002/jimd.12507] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 11/28/2022]
Abstract
Exome sequencing (ES) in the clinical setting of inborn metabolic diseases (IMDs) has created tremendous improvement in achieving an accurate and timely molecular diagnosis for a greater number of patients, but it still leaves the majority of patients without a diagnosis. In parallel, (personalized) treatment strategies are increasingly available, but this requires the availability of a molecular diagnosis. IMDs comprise an expanding field with the ongoing identification of novel disease genes and the recognition of multiple inheritance patterns, mosaicism, variable penetrance, and expressivity for known disease genes. The analysis of trio ES is preferred over singleton ES as information on the allelic origin (paternal, maternal, "de novo") reduces the number of variants that require interpretation. All ES data and interpretation strategies should be exploited including CNV and mitochondrial DNA analysis. The constant advancements in available techniques and knowledge necessitate the close exchange of clinicians and molecular geneticists about genotypes and phenotypes, as well as knowledge of the challenges and pitfalls of ES to initiate proper further diagnostic steps. Functional analyses (transcriptomics, proteomics, and metabolomics) can be applied to characterize and validate the impact of identified variants, or to guide the genomic search for a diagnosis in unsolved cases. Future diagnostic techniques (genome sequencing [GS], optical genome mapping, long-read sequencing, and epigenetic profiling) will further enhance the diagnostic yield. We provide an overview of the challenges and limitations inherent to ES followed by an outline of solutions and a clinical checklist, focused on establishing a diagnosis to eventually achieve (personalized) treatment.
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Affiliation(s)
- Saskia B. Wortmann
- Radboud Center for Mitochondrial and Metabolic Medicine, Department of PediatricsAmalia Children's Hospital, Radboud University Medical CenterNijmegenThe Netherlands
- University Children's Hospital, Paracelsus Medical UniversitySalzburgAustria
| | - Machteld M. Oud
- United for Metabolic DiseasesAmsterdamThe Netherlands
- Department of Human GeneticsDonders Institute for Brain, Cognition and Behaviour, Radboud University Medical CenterNijmegenThe Netherlands
| | - Mariëlle Alders
- Department of Human GeneticsAmsterdam UMC, University of Amsterdam, Amsterdam Reproduction and Development Research InstituteAmsterdamThe Netherlands
| | - Karlien L. M. Coene
- United for Metabolic DiseasesAmsterdamThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Saskia N. van der Crabben
- Department of Human GeneticsAmsterdam University Medical Centers, University of AmsterdamAmsterdamThe Netherlands
| | - René G. Feichtinger
- University Children's Hospital, Paracelsus Medical UniversitySalzburgAustria
| | - Alejandro Garanto
- Radboud Center for Mitochondrial and Metabolic Medicine, Department of PediatricsAmalia Children's Hospital, Radboud University Medical CenterNijmegenThe Netherlands
- Department of PediatricsAmalia Children's Hospital, Radboud Institute for Molecular LifesciencesNijmegenThe Netherlands
- Department of Human GeneticsRadboud Institute for Molecular LifesciencesNijmegenThe Netherlands
| | - Alex Hoischen
- Department of Human Genetics, Department of Internal Medicine and Radboud Center for Infectious DiseasesRadboud Institute of Medical Life Sciences, Radboud University Medical CenterNijmegenthe Netherlands
| | - Mirjam Langeveld
- Department of Endocrinology and MetabolismAmsterdam University Medical Centers, location AMC, University of AmsterdamAmsterdamThe Netherlands
| | - Dirk Lefeber
- United for Metabolic DiseasesAmsterdamThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
- Department of Neurology, Donders Institute for BrainCognition and Behaviour, Radboud University Medical CenterNijmegenThe Netherlands
| | - Johannes A. Mayr
- University Children's Hospital, Paracelsus Medical UniversitySalzburgAustria
| | - Charlotte W. Ockeloen
- Department of Human GeneticsRadboud Institute for Molecular LifesciencesNijmegenThe Netherlands
| | - Holger Prokisch
- School of MedicineInstitute of Human Genetics, Technical University Munich and Institute of NeurogenomicsNeuherbergGermany
| | - Richard Rodenburg
- Radboud Center for Mitochondrial and Metabolic MedicineTranslational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical CenterNijmegenThe Netherlands
| | - Hans R. Waterham
- United for Metabolic DiseasesAmsterdamThe Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Clinical ChemistryAmsterdam University Medical Centers, location AMC, University of AmsterdamAmsterdamThe Netherlands
| | - Ron A. Wevers
- United for Metabolic DiseasesAmsterdamThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Bart P. C. van de Warrenburg
- Department of Neurology, Donders Institute for BrainCognition and Behaviour, Radboud University Medical CenterNijmegenThe Netherlands
| | - Michel A. A. P. Willemsen
- Departments of Pediatric Neurology and PediatricsAmalia Children's Hospital, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical CenterNijmegenThe Netherlands
| | - Nicole I. Wolf
- Amsterdam Leukodystrophy Center, Department of Child NeurologyEmma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Lisenka E. L. M. Vissers
- Department of Human GeneticsDonders Institute for Brain, Cognition and Behaviour, Radboud University Medical CenterNijmegenThe Netherlands
| | - Clara D. M. van Karnebeek
- Radboud Center for Mitochondrial and Metabolic Medicine, Department of PediatricsAmalia Children's Hospital, Radboud University Medical CenterNijmegenThe Netherlands
- United for Metabolic DiseasesAmsterdamThe Netherlands
- Department of Human GeneticsAmsterdam UMC, University of Amsterdam, Amsterdam Reproduction and Development Research InstituteAmsterdamThe Netherlands
- Department of Pediatrics, Emma Center for Personalized MedicineAmsterdam University Medical Centers, Amsterdam, Amsterdam Genetics Endocrinology Metabolism Research Institute, University of AmsterdamAmsterdamThe Netherlands
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6
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One Molecule for Mental Nourishment and More: Glucose Transporter Type 1—Biology and Deficiency Syndrome. Biomedicines 2022; 10:biomedicines10061249. [PMID: 35740271 PMCID: PMC9219734 DOI: 10.3390/biomedicines10061249] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/17/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023] Open
Abstract
Glucose transporter type 1 (Glut1) is the main transporter involved in the cellular uptake of glucose into many tissues, and is highly expressed in the brain and in erythrocytes. Glut1 deficiency syndrome is caused mainly by mutations of the SLC2A1 gene, impairing passive glucose transport across the blood–brain barrier. All age groups, from infants to adults, may be affected, with age-specific symptoms. In its classic form, the syndrome presents as an early-onset drug-resistant metabolic epileptic encephalopathy with a complex movement disorder and developmental delay. In later-onset forms, complex motor disorder predominates, with dystonia, ataxia, chorea or spasticity, often triggered by fasting. Diagnosis is confirmed by hypoglycorrhachia (below 45 mg/dL) with normal blood glucose, 18F-fluorodeoxyglucose positron emission tomography, and genetic analysis showing pathogenic SLC2A1 variants. There are also ongoing positive studies on erythrocytes’ Glut1 surface expression using flow cytometry. The standard treatment still consists of ketogenic therapies supplying ketones as alternative brain fuel. Anaplerotic substances may provide alternative energy sources. Understanding the complex interactions of Glut1 with other tissues, its signaling function for brain angiogenesis and gliosis, and the complex regulation of glucose transportation, including compensatory mechanisms in different tissues, will hopefully advance therapy. Ongoing research for future interventions is focusing on small molecules to restore Glut1, metabolic stimulation, and SLC2A1 transfer strategies. Newborn screening, early identification and treatment could minimize the neurodevelopmental disease consequences. Furthermore, understanding Glut1 relative deficiency or inhibition in inflammation, neurodegenerative disorders, and viral infections including COVID-19 and other settings could provide clues for future therapeutic approaches.
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7
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Striano P, Auvin S, Collins A, Horvath R, Scheffer IE, Tzadok M, Miller I, Koenig MK, Lacy A, Davis R, Garcia-Cazorla A, Saneto RP, Brandabur M, Blair S, Koutsoukos T, De Vivo D. A randomized, double-blind trial of triheptanoin for drug-resistant epilepsy in glucose transporter I deficiency syndrome (Glut1DS). Epilepsia 2022; 63:1748-1760. [PMID: 35441706 PMCID: PMC9546029 DOI: 10.1111/epi.17263] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Evaluate efficacy and long-term safety of triheptanoin in patients >1 year old, not on a ketogenic diet, with drug-resistant seizures associated with Glucose Transporter Type 1 Deficiency Syndrome (Glut1DS). METHODS UX007G-CL201 was a randomized, double-blind, placebo-controlled trial. Following a 6-week baseline period, eligible patients were randomized 3:1 to triheptanoin or placebo. Dosing was titrated to 35% total daily calories over 2 weeks. After an 8-week placebo-controlled period, all patients received open-label triheptanoin through Week 52. RESULTS The study included 36 patients (15 children; 13 adolescents; 8 adults). A median 12.6% reduction in overall seizure frequency was observed in the triheptanoin arm relative to baseline and a 13.5% difference was observed relative to placebo (p = .58). In patients with absence seizures only (n = 9), a median 62.2% reduction in seizure frequency was observed in the triheptanoin arm relative to baseline. Only one patient with absence seizures only was present in the control group, preventing comparison. No statistically significant differences in seizure frequency were observed. Common treatment-emergent adverse events (TEAEs) included diarrhea, vomiting, abdominal pain, and nausea, most mild or moderate in severity. No serious AEs were considered treatment related. One patient discontinued due to status epilepticus. SIGNIFICANCE Triheptanoin did not significantly reduce seizure frequency in patients with Glut1DS not on the ketogenic diet. Treatment was associated with mild to moderate GI treatment-related events; most resolved following dose reduction or interruption and/or medication for treatment. Triheptanoin was not associated with any long-term safety concerns when administered at dose levels up to 35% total daily caloric intake for up to one year.
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Affiliation(s)
- Pasquale Striano
- IRCCS Istituto 'G. Gaslini', Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Stéphane Auvin
- Robert-Debré University Hospital and Université de Paris, Paris, France.,Institut Universitaire de France (IUF), Paris, France
| | | | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ingrid E Scheffer
- Austin and Royal Children's Hospital, Florey and Murdoch Institutes, University of Melbourne, Melbourne, Vic., Australia
| | - Michal Tzadok
- Pediatric Neurology Units, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel-Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel-Aviv University, Ramat Gan, Israel
| | - Ian Miller
- Miami Children's Research Institute, Miami, Florida, USA
| | | | - Adrian Lacy
- Cook Children's Medical Center, Fort Worth, Texas, USA
| | - Ronald Davis
- Neurology & Epilepsy Research Center, DBO Pediatric Neurology, P.A., Orlando, Florida, USA
| | | | - Russell P Saneto
- Department of Neurology, Division of Pediatric Neurology, University of Washington/ Seattle Children's Hospital, Seattle, Washington, USA
| | | | - Susan Blair
- Ultragenyx Pharmaceutical Inc., Novato, California, USA
| | | | - Darryl De Vivo
- Columbia University Irving Medical Center, New York, New York, USA
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8
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Saleh DA, Attia AAEM. Shedding light on the phenotypic–genotypic correlation of rare treatable and potentially treatable pediatric movement disorders. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00286-w] [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
Advances in genetic science have led to the identification of many rare treatable pediatric movements disorders (MDs). We explored the phenotypic–genotypic spectrum of pediatric patients presenting with MDs. By this, we aimed at raising awareness about such rare disorders, especially in our region. Over the past 3 years, we reviewed the demographic data, clinical profile, molecular genetics and other diagnostic workups of pediatric patients presenting with MDs.
Results
Twelve patients were identified; however, only six patients were genetically confirmed. The phenomenology of MDs ranged from paroxysmal kinesigenic choreoathetosis (1 patient), exercise-induced dyskinesia (2 patients), ataxia (2 patients) and dystonia (2 patients). Whole-exome sequencing in addition to the functional studies for some patients revealed a specific genetic diagnosis being responsible for their MDs. The genetic diagnosis of our patients included infantile convulsions and paroxysmal choreoathetosis syndrome and episodic ataxia due to “pathogenic homozygous mutation of PRRT2 gene,” glucose transporter type 1 deficiency-exercise induced dyskinesia due to “De Novo pathogenic heterozygous missense mutation of exon 4 of SLC2A1 gene,” aromatic L amino acid decarboxylase deficiency due to “pathogenic homozygous mutation of the DDC gene,” myopathy with extrapyramidal signs due to “likely pathogenic homozygous mutations of the MICU1 gene,” mitochondrial trifunctional protein deficiency due to “homozygous variant of uncertain significance (VUS) of HADHB gene” and glutaric aciduria II with serine deficiency due to “homozygous VUS for both ETFDH and PHGDH genes.” After receiving the treatment as per recognized treatment protocols, two patients showed complete resolution of symptoms and the rest showed variable responses.
Conclusion
Identifying the genetic etiology of our patients guided us to provide either disease-specific treatment or redirected our management plan. Hence, highlighting the value of molecular genetic analysis to avoid the diagnostic odyssey and identify treatable MDs.
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9
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McDonald CJ, Blankenheim ZJ, Drewes LR. Brain Endothelial Cells: Metabolic Flux and Energy Metabolism. Handb Exp Pharmacol 2022; 273:59-79. [PMID: 34251530 DOI: 10.1007/164_2021_494] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The neurovascular unit (NVU) consists of multiple cell types including brain endothelial cells, pericytes, astrocytes, and neurons that function collectively to maintain homeostasis within the CNS microenvironment. As the principal barrier-forming component of the NVU, the endothelial cells perform an array of complex functions that require substantial energy resources. The principal metabolic pathways for producing ATP are glycolysis and mitochondrial oxidative phosphorylation. While previous studies have demonstrated that glycolysis is a primary pathway for most endothelial cells, details about the energy producing pathways of brain endothelial cells are not fully characterized. The contributions of glycolysis and mitochondrial respiration to energy metabolism are quantifiable using metabolic flux analysis that measures cellular oxygen consumption and acidification (proton production) in a closed microtiter plate format. ATP production rates are then calculated. The bioenergetics of the human brain microvascular endothelial cell line, hCMEC/D3, indicate that these cells exhibit relatively elevated rates of glycolytic flux and glycolytic ATP production, thus confirming their glycolytic nature even in the presence of abundant oxygen. Furthermore, energy producing pathways involving mitochondrial respiration are relatively low, although contributing significantly to total ATP production. Interestingly, the bioenergetics of the hCMEC/D3 cells are relatively similar to those of human primary brain microvascular endothelial cells (hBVECs). These findings allow a quantitative understanding of the bioenergetics of brain endothelial cells in a cultured and proliferative state and also provide a platform for comparative studies of disease states and conditions involving exposures to drugs or metabolic disruptors.
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Affiliation(s)
- Cade J McDonald
- Department of Biomedical Sciences, University of Minnesota Duluth Medical School, Duluth, MN, USA
| | - Zachery J Blankenheim
- Department of Biomedical Sciences, University of Minnesota Duluth Medical School, Duluth, MN, USA
| | - Lester R Drewes
- Department of Biomedical Sciences, University of Minnesota Duluth Medical School, Duluth, MN, USA.
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Nguyen YTK, Ha HTT, Nguyen TH, Nguyen LN. The role of SLC transporters for brain health and disease. Cell Mol Life Sci 2021; 79:20. [PMID: 34971415 PMCID: PMC11071821 DOI: 10.1007/s00018-021-04074-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 09/05/2021] [Accepted: 10/21/2021] [Indexed: 12/19/2022]
Abstract
The brain exchanges nutrients and small molecules with blood via the blood-brain barrier (BBB). Approximately 20% energy intake for the body is consumed by the brain. Glucose is known for its critical roles for energy production and provides substrates for biogenesis in neurons. The brain takes up glucose via glucose transporters GLUT1 and 3, which are expressed in several neural cell types. The brain is also equipped with various transport systems for acquiring amino acids, lactate, ketone bodies, lipids, and cofactors for neuronal functions. Unraveling the mechanisms by which the brain takes up and metabolizes these nutrients will be key in understanding the nutritional requirements in the brain. This could also offer opportunities for therapeutic interventions in several neurological disorders. For instance, emerging evidence suggests a critical role of lactate as an alternative energy source for neurons. Neuronal cells express monocarboxylic transporters to acquire lactate. As such, treatment of GLUT1-deficient patients with ketogenic diets to provide the brain with alternative sources of energy has been shown to improve the health of the patients. Many transporters are present in the brain, but only a small number has been characterized. In this review, we will discuss about the roles of solute carrier (SLC) transporters at the blood brain barrier (BBB) and neural cells, in transport of nutrients and metabolites in the brain.
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Affiliation(s)
- Yen T K Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore
| | - Hoa T T Ha
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore
| | - Tra H Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore
| | - Long N Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore.
- SLING/Immunology Program, Life Sciences Institute, National University of Singapore, Singapore, 117456, Singapore.
- Immunology Translational and Cardiovascular Disease Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
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11
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Hu Q, Shen Y, Su T, Liu Y, Xu S. Clinical and Genetic Characteristics of Chinese Children With GLUT1 Deficiency Syndrome: Case Report and Literature Review. Front Genet 2021; 12:734481. [PMID: 34880899 PMCID: PMC8645975 DOI: 10.3389/fgene.2021.734481] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/18/2021] [Indexed: 11/24/2022] Open
Abstract
Objective: GLUT1 deficiency syndrome (GLUT1-DS) is a rare, treatable neurometabolic disorder. However, its diagnosis may be challenging due to the various and evolving phenotypes. Here we report the first Chinese familial cases with genetically confirmed GLUT1-DS and analyze the characteristics of Chinese children with GLUT1-DS from clinical, laboratory, and genetic aspects. Methods: We reported a Chinese family with three members affected with GLUT1-DS and searched for relevant articles up to September 2020 from PubMed, WOS, CNKI, and WanFang databases. A total of 30 Chinese patients diagnosed with GLUT1-DS (three newly identified patients in one family and 27 previously reported ones) were included and analyzed in this study. Results: The median age of onset of the 30 patients (male: 18, female: 12) was 8.5 months (range, 33 days to 10 years). Epileptic seizures were found in 25 patients, most with generalized tonic–clonic and focal ones. Movement disorders were found in 20 patients—frequently with ataxia and dystonia, developmental delay in 25 patients, and microcephaly only in six patients. The cerebrospinal fluid (CSF) analysis showed decreased CSF glucose (median: 1.63 mmol/L, range: 1.1–2.6 mmol/L) and glucose ratio of CSF to blood (median: 0.340; range: 0.215–0.484). The genetic testing performed in 28 patients revealed 27 cases with pathogenic variations of the SLC2A1 gene, including 10 missense, nine frameshift, three nonsense, three large fragment deletions, and two splice-site mutations. Most patients had a good response to the treatment of ketogenic diet or regular diet with increased frequency. Although three patients in this Chinese family carried the same pathogenic mutation c.73C > T (p.Q25X) in the SLC2A1 gene, their symptoms and responses to treatment were not exactly the same. Conclusion: The clinical manifestations of GLUT1-DS are heterogeneous, even among family members sharing the same mutation. For children with unexplained epileptic seizures, developmental delay, and complex movement disorders, detection of low CSF glucose or SLC2A1 gene mutations is helpful for the diagnosis of GLUT1-DS. Early initiation of ketogenic diet treatment significantly improves the symptoms and prognosis of GLUT1-DS.
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Affiliation(s)
- Qingqing Hu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yuechi Shen
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tangfeng Su
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Liu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sanqing Xu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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12
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Bozkurt T, Alanay Y, Isik U, Sezerman U. Re-analysis of whole-exome sequencing data reveals a novel splicing variant in the SLC2A1 in a patient with GLUT1 Deficiency Syndrome 1 accompanied by hemangioma: a case report. BMC Med Genomics 2021; 14:197. [PMID: 34332575 PMCID: PMC8325841 DOI: 10.1186/s12920-021-01045-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 07/22/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND GLUT1 Deficiency Syndrome 1 (GLUT1DS1) is a neurological disorder caused by either heterozygous or homozygous mutations in the Solute Carrier Family 2, Member 1 (SLC2A1) gene. SLC2A1 encodes Glucose transporter type 1 (GLUT1) protein, which is the primary glucose transporter at the blood-brain barrier. A ketogenic diet (KD) provides an alternative fuel for brain metabolism to treat impaired glucose transport. By reanalyzing exome data, we identified a de novo heterozygous SLC2A1 variant in a girl with epilepsy. After reversed phenotyping with neurometabolic tests, she was diagnosed with GLUT1DS1 and started on a KD. The patient's symptoms responded to the diet. Here, we report a patient with GLUT1DS1 with a novel SLC2A1 mutation. She also has a hemangioma which has not been reported in association with this syndrome before. CASE PRESENTATION A 5-year 8-month girl with global developmental delay, spasticity, intellectual disability, dysarthric speech, abnormal eye movements, and hemangioma. The electroencephalography (EEG) result revealed that she had epilepsy. Magnetic resonance imaging (MRI) showed that non-specific white matter abnormalities. Whole Exome Sequencing (WES) was previously performed, but the case remained unsolved. The re-analysis of WES data revealed a heterozygous splicing variant in the SLC2A1 gene. Segregation analysis with parental DNA samples indicated that the variant occurred de novo. Lumbar puncture (LP) confirmed the diagnosis, and the patient started on a KD. Her seizures responded to the KD. She has been seizure-free since shortly after the initiation of the diet. She also had decreased involuntary movements, her speech became more understandable, and her vocabulary increased after the diet. CONCLUSIONS We identified a novel de novo variant in the SLC2A1 gene in a patient who previously had a negative WES result. The patient has been diagnosed with GLUT1DS1. The syndrome is a treatable condition, but the differential diagnosis is not an easy process due to showing a wide range of phenotypic spectrum and the overlapping symptoms with other neurological diseases. The diagnosis necessitates a genomic testing approach. Our findings also highlight the importance of re-analysis to undiagnosed cases after initial WES to reveal disease-causing variants.
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Affiliation(s)
- Tugce Bozkurt
- Biostatistics and Bioinformatics Program, Graduate School of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Yasemin Alanay
- Division of Pediatric Genetics, Department of Pediatrics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Ugur Isik
- Division of Pediatric Neurology, Department of Pediatrics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Ugur Sezerman
- Biostatistics and Bioinformatics Program, Graduate School of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey.
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13
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Gonzalez-Resines S, Quinn PJ, Naftalin RJ, Domene C. Multiple Interactions of Glucose with the Extra-Membranous Loops of GLUT1 Aid Transport. J Chem Inf Model 2021; 61:3559-3570. [PMID: 34260246 DOI: 10.1021/acs.jcim.1c00310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Molecular dynamics simulations amounting to ≈8 μs demonstrate that the glucose transporter GLUT1 undergoes structural fluctuations mediated by the fluidity of the lipid bilayer and the proximity to glucose. The fluctuations of GLUT1 increase as the glucose concentration is raised. These fluctuations are more pronounced when the lipid bilayer is in the fluid compared to the gel phase. Glucose interactions are confined to the extra-membranous residues when the lipid is in the gel phase but diffuses into the transmembrane regions in the fluid phase. Proximity of glucose to GLUT1 causes asynchronous expansions of key bottlenecks at the internal and external openings of the central pore. This is accomplished only by small conformational changes at the single residue level that lower the resistance to glucose movements, thereby permitting unsteered glucose and water movements along the entire length of the pore. When glucose is near salt bridges located at the external and internal openings of the central pore, the distance separating the polar amino acid residues guarding these apertures tends to increase in both fluid and gel phases. It is evident that the multiplicity of glucose interactions, obtained with high concentrations, amplifies the structural fluctuations in GLUT1. The findings that most of the salt bridges and the bottlenecks appear to be operated by glucose proximity suggest that the main triggers to activation of transport are located within the solvent accessible linker regions in the extramembranous zones.
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Affiliation(s)
| | - Peter J Quinn
- Department of Biochemistry, King's College London, London WC2R 2LS, U.K
| | - Richard J Naftalin
- BHF Centre of Research Excellence, School of Medicine and Life Sciences, King's College London, London WC2R 2LS, U.K
| | - Carmen Domene
- Departments of Chemistry, University of Bath, Bath BA2 7AX, U.K.,Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
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14
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Yu M, Miao J, Lv Y, Wang X, Zhang W, Shao N, Meng H. A Challenging Diagnosis of Atypical Glut1-DS: A Case Report and Literature Review. Front Neurol 2021; 11:549331. [PMID: 33584489 PMCID: PMC7876440 DOI: 10.3389/fneur.2020.549331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 12/21/2020] [Indexed: 11/16/2022] Open
Abstract
Glucose transporter type 1 deficiency syndrome (Glut1-DS) is a rare neurometabolic disorder caused by mutations of the SLC2A1 gene. Paroxysmal exercise-induced dyskinesia is regarded as a representative symptom of Glut1-DS. Paroxysmal non-kinesigenic dyskinesia is usually caused by aberrations of the MR1 and KCNMA1 genes, but it also appears in Glut1-DS. We herein document a patient with Glut1-DS who suffered first from paroxysmal exercise-induced dyskinesia and subsequently paroxysmal non-kinesigenic dyskinesia and experienced a recent worsening of symptoms accompanied with a low fever. The lumbar puncture result showed a decreased glucose concentration and increased white blood cell (WBC) count in cerebrospinal fluid (CSF). The exacerbated symptoms were initially suspected to be caused by intracranial infection due to a mild fever of <38.0°C, decreased CSF glucose, and increased CSF WBC count. However, the second lumbar puncture result indicated a decreased glucose concentration and normal WBC count in CSF with no anti-infective agents, and the patient's symptoms were not relieved apparently. The continuous low glucose concentration attracted our attention, and gene analysis was performed. According to the gene analysis result, the patient was diagnosed with Glut1-DS finally. This case indicates that the complex paroxysmal dyskinesia in Glut1-DS may be confusing and pose challenges for accurate diagnosis. Except intracranial infection, Glut1-DS should be considered as a differential diagnosis upon detection of a low CSF glucose concentration and dyskinesia. The case presented here may encourage clinicians to be mindful of this atypical manifestation of Glut1-DS in order to avoid misdiagnosis.
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Affiliation(s)
- Miaomiao Yu
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Jing Miao
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Yudan Lv
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Xue Wang
- Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Wuqiong Zhang
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Na Shao
- Weifang Traditional Chinese Medicine Hospital, Weifang, China
| | - Hongmei Meng
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
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15
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Takahashi S, Tanaka R, Takeguchi R, Kuroda M, Akaba Y, Ito Y. The role of molecular analysis of SLC2A1 in the diagnostic workup of glucose transporter 1 deficiency syndrome. J Neurol Sci 2020; 416:117041. [PMID: 32712428 DOI: 10.1016/j.jns.2020.117041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/24/2020] [Accepted: 07/13/2020] [Indexed: 10/23/2022]
Abstract
The study aimed to investigate the role of molecular analysis of SLC2A1 in the diagnostic workup of glucose transporter 1 deficiency syndrome (Glut1DS). During 2006-2020, we received 100 requests for SLC2A1 variant analysis of patients clinically suspected for Glut1DS. Pathogenic variants were detected in 37 patients, among whom 11 were familial cases. Most patients presented with epilepsy (n = 31; 84%), movement disorders (MD) (n = 28; 76%), and intellectual disabilities (ID) (n = 29; 78%). Moreover, paroxysmal dyskinesias (PD) (n = 10; 27%) were more frequently seen in familial cases (55%) than in sporadic cases (15%) (p < .05). The Glut1DS patients with ID typically had either epilepsy or MD. The presence of MD, particularly when associated with epilepsy or ID, indicated Glut1DS (p < .05). The cerebrospinal fluid (CSF) glucose levels were at or below the 10th percentile in all 32 SLC2A1-positive patients but only in 16 of 52 (31%) SLC2A1-negative patients (p < .05). Thus, CSF analysis is an essential tool in the diagnostic workup of Glut1DS. SLC2A1 molecular analysis should be performed in patients with a family history of Glut1DS or with at least one of the following clinical features, such as epilepsy, MD, and PD with or without ID, and low CSF glucose level. This would help in precise molecular diagnosis of the disease and facilitate effective treatment and appropriate genetic counseling.
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Affiliation(s)
- Satoru Takahashi
- Department of Pediatrics, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510, Japan.
| | - Ryosuke Tanaka
- Department of Pediatrics, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510, Japan
| | - Ryo Takeguchi
- Department of Pediatrics, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510, Japan
| | - Mami Kuroda
- Department of Pediatrics, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510, Japan
| | - Yuichi Akaba
- Department of Pediatrics, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510, Japan
| | - Yasushi Ito
- Department of Pediatrics, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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16
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Glucose transporters in brain in health and disease. Pflugers Arch 2020; 472:1299-1343. [PMID: 32789766 PMCID: PMC7462931 DOI: 10.1007/s00424-020-02441-x] [Citation(s) in RCA: 219] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
Energy demand of neurons in brain that is covered by glucose supply from the blood is ensured by glucose transporters in capillaries and brain cells. In brain, the facilitative diffusion glucose transporters GLUT1-6 and GLUT8, and the Na+-d-glucose cotransporters SGLT1 are expressed. The glucose transporters mediate uptake of d-glucose across the blood-brain barrier and delivery of d-glucose to astrocytes and neurons. They are critically involved in regulatory adaptations to varying energy demands in response to differing neuronal activities and glucose supply. In this review, a comprehensive overview about verified and proposed roles of cerebral glucose transporters during health and diseases is presented. Our current knowledge is mainly based on experiments performed in rodents. First, the functional properties of human glucose transporters expressed in brain and their cerebral locations are described. Thereafter, proposed physiological functions of GLUT1, GLUT2, GLUT3, GLUT4, and SGLT1 for energy supply to neurons, glucose sensing, central regulation of glucohomeostasis, and feeding behavior are compiled, and their roles in learning and memory formation are discussed. In addition, diseases are described in which functional changes of cerebral glucose transporters are relevant. These are GLUT1 deficiency syndrome (GLUT1-SD), diabetes mellitus, Alzheimer’s disease (AD), stroke, and traumatic brain injury (TBI). GLUT1-SD is caused by defect mutations in GLUT1. Diabetes and AD are associated with changed expression of glucose transporters in brain, and transporter-related energy deficiency of neurons may contribute to pathogenesis of AD. Stroke and TBI are associated with changes of glucose transporter expression that influence clinical outcome.
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17
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Clinical and Genetic Overview of Paroxysmal Movement Disorders and Episodic Ataxias. Int J Mol Sci 2020; 21:ijms21103603. [PMID: 32443735 PMCID: PMC7279391 DOI: 10.3390/ijms21103603] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/15/2022] Open
Abstract
Paroxysmal movement disorders (PMDs) are rare neurological diseases typically manifesting with intermittent attacks of abnormal involuntary movements. Two main categories of PMDs are recognized based on the phenomenology: Paroxysmal dyskinesias (PxDs) are characterized by transient episodes hyperkinetic movement disorders, while attacks of cerebellar dysfunction are the hallmark of episodic ataxias (EAs). From an etiological point of view, both primary (genetic) and secondary (acquired) causes of PMDs are known. Recognition and diagnosis of PMDs is based on personal and familial medical history, physical examination, detailed reconstruction of ictal phenomenology, neuroimaging, and genetic analysis. Neurophysiological or laboratory tests are reserved for selected cases. Genetic knowledge of PMDs has been largely incremented by the advent of next generation sequencing (NGS) methodologies. The wide number of genes involved in the pathogenesis of PMDs reflects a high complexity of molecular bases of neurotransmission in cerebellar and basal ganglia circuits. In consideration of the broad genetic and phenotypic heterogeneity, a NGS approach by targeted panel for movement disorders, clinical or whole exome sequencing should be preferred, whenever possible, to a single gene approach, in order to increase diagnostic rate. This review is focused on clinical and genetic features of PMDs with the aim to (1) help clinicians to recognize, diagnose and treat patients with PMDs as well as to (2) provide an overview of genes and molecular mechanisms underlying these intriguing neurogenetic disorders.
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18
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Raja M, Kinne RKH. Mechanistic Insights into Protein Stability and Self-aggregation in GLUT1 Genetic Variants Causing GLUT1-Deficiency Syndrome. J Membr Biol 2020; 253:87-99. [PMID: 32025761 PMCID: PMC7150661 DOI: 10.1007/s00232-020-00108-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 01/14/2020] [Indexed: 12/23/2022]
Abstract
Human sodium-independent glucose cotransporter 1 (hGLUT1) has been studied for its tetramerization and multimerization at the cell surface. Homozygous or compound heterozygous mutations in hGLUT1 elicit GLUT1-deficiency syndrome (GLUT1-DS), a metabolic disorder, which results in impaired glucose transport into the brain. The reduced cell surface expression or loss of function have been shown for some GLUT1 mutants. However, the mechanism by which deleterious mutations affect protein structure, conformational stability and GLUT1 oligomerization is not known and require investigation. In this review, we combined previous knowledge of GLUT1 mutations with hGLUT1 crystal structure to analyze native interactions and several natural single-point mutations. The modeling of native hGLUT1 structure confirmed the roles of native residues in forming a range of side-chain interactions. Interestingly, the modeled mutants pointed to the formation of a variety of non-native novel interactions, altering interaction networks and potentially eliciting protein misfolding. Self-aggregation of the last part of hGLUT1 was predicted using protein aggregation prediction tool. Furthermore, an increase in aggregation potential in the aggregation-prone regions was estimated for several mutants suggesting increased aggregation of misfolded protein. Protein stability change analysis predicted that GLUT1 mutant proteins are unstable. Combining GLUT1 oligomerization behavior with our modeling, aggregation prediction, and protein stability analyses, this work provides state-of-the-art view of GLUT1 genetic mutations that could destabilize native interactions, generate novel interactions, trigger protein misfolding, and enhance protein aggregation in a disease state.
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Affiliation(s)
- Mobeen Raja
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
- Algonquin College, 1385 Woodroffe Avenue, Ottawa, ON K2G 1V8 Canada
| | - Rolf K. H. Kinne
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
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Yu WH, Chen LW, Wang ST, Tu YF, Huang CC. Developmental outcomes and prevalence of SLC2A1 variants in young infants with hypoglycorrhachia. Brain Dev 2019; 41:854-861. [PMID: 31326153 DOI: 10.1016/j.braindev.2019.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 11/15/2022]
Abstract
INTRODUCTION The neurodevelopmental outcomes of young infants with hypoglycorrhachia that is comparable to glucose transporter 1 deficiency syndrome (GLUT1DS), i.e. cerebrospinal fluid (CSF) glucose ≤40 mg/dL and CSF lactate <2.2 mM without causes of secondary hypoglycorrhachia are unknown. This study investigated the developmental outcomes and possibility of GLUT1DS in infants with hypoglycorrhachia, or low CSF glucose concentration. MATERIAL AND METHODS 1655 neurologically asymptomatic infants aged <4 months had CSF examinations for fever workup from 2006 to 2016. Among the infants with normal CSF cell counts and without isolated pathogens, there were hypoglycorrhachia group who had CSF glucose levels that were comparable to GLUT1DS, and age- and gender-matched non-hypoglycorrhachia group. Both groups were at a mean age of 5.9 ± 2.4 years (ranged 1-10 years) at neurodevelopmental evaluation in 2017. Mutational analysis of solute-carrier-family 2, which facilitated the glucose transporter member 1 (SLC2A1) gene was performed. RESULTS Among the 722 infants with normal CSF cell counts and without isolated pathogens, 30 (4.2%) had hypoglycorrhachia that was comparable to GLUT1DS. In the 25 infants with hypoglycorrhachia available for follow-up, 4 (16%) had abnormal outcomes, of which 3 (12%) had the history of mixed-type developmental delay before age 6 and 1 (4%) had type 1 diabetes mellitus. In the non-hypoglycorrhachia control group (n = 50), 2 patients (4%) showed abnormal outcomes, both with the history of pure speech delay. The hypoglycorrhachia group had a higher rate of the history of mixed-type of developmental delay than the control group (12% vs. 0%, P = 0.034). No SLC2A1 pathogenic variants were observed in the hypoglycorrhachia group. CONCLUSION Hypoglycorrhachia may be a potential biomarker for neurodevelopmental delay instead of for GLUT1DS in neurologically asymptomatic young infants.
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Affiliation(s)
- Wen-Hao Yu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Graduate Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Li-Wen Chen
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Graduate Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shan-Tair Wang
- Institute of Gerontology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Fang Tu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Graduate Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chao-Ching Huang
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Pediatrics, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Usefulness of diagnostic tools in a GLUT1 deficiency syndrome patient with 2 inherited mutations. Brain Dev 2019; 41:808-811. [PMID: 31196579 DOI: 10.1016/j.braindev.2019.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 04/10/2019] [Accepted: 05/28/2019] [Indexed: 11/22/2022]
Abstract
UNLABELLED In some patients with GLUT1 deficiency syndrome (GLUT1-DS), the diagnosis can be difficult to reach. We report a child with 2 inherited mutations suggesting an autosomal recessive transmission of SLC2A1 mutations. METHODS The child and her parents were explored with erythrocyte 3-O-methyl-d-Glucose uptake, glucose uptake in oocytes expressing GLUT1 with the gene mutations and measure of the expression of GLUT1 at the surface of the circulating red blood cells by flow cytometry (METAglut1™ test). RESULTS Both erythrocyte glucose uptake and glucose uptake in oocyte with the patient's mutations did not support the diagnosis of a mild GLUT1-DS phenotype with autosomal recessive transmission of SLC2A1 mutations. Instead, GLUT-1 expression at the surface of the erythrocytes appeared to better correlate with the clinical phenotypes in this family. CONCLUSION The diagnostic value of these functional/expression tools need to be further studied with a focus on mild phenotype of GLUT1-DS.
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Tang M, Park SH, De Vivo DC, Monani UR. Therapeutic strategies for glucose transporter 1 deficiency syndrome. Ann Clin Transl Neurol 2019; 6:1923-1932. [PMID: 31464092 PMCID: PMC6764625 DOI: 10.1002/acn3.50881] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/08/2019] [Accepted: 08/10/2019] [Indexed: 01/01/2023] Open
Abstract
Proper development and function of the mammalian brain is critically dependent on a steady supply of its chief energy source, glucose. Such supply is mediated by the glucose transporter 1 (Glut1) protein. Paucity of the protein stemming from mutations in the associated SLC2A1 gene deprives the brain of glucose and triggers the infantile‐onset neurodevelopmental disorder, Glut1 deficiency syndrome (Glut1 DS). Considering the monogenic nature of Glut1 DS, the disease is relatively straightforward to model and thus study. Accordingly, Glut1 DS serves as a convenient paradigm to investigate the more general cellular and molecular consequences of brain energy failure. Here, we review how Glut1 DS models have informed the biology of a prototypical brain energy failure syndrome, how these models are facilitating the development of promising new treatments for the human disease, and how important insights might emerge from the study of Glut1 DS to illuminate the myriad conditions involving the Glut1 protein.
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Affiliation(s)
- Maoxue Tang
- Department of Pathology & Cell Biology, Columbia University Medical Center, New York, New York, 10032.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, 10032
| | - Sarah H Park
- Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, 10032.,Department of Neurology, Columbia University Medical Center, New York, New York, 10032
| | - Darryl C De Vivo
- Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, 10032.,Department of Neurology, Columbia University Medical Center, New York, New York, 10032
| | - Umrao R Monani
- Department of Pathology & Cell Biology, Columbia University Medical Center, New York, New York, 10032.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, 10032.,Department of Neurology, Columbia University Medical Center, New York, New York, 10032
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22
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De Gusmao CM, Silveira-Moriyama L. Paroxysmal movement disorders - practical update on diagnosis and management. Expert Rev Neurother 2019; 19:807-822. [PMID: 31353980 DOI: 10.1080/14737175.2019.1648211] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Paroxysmal dyskinesias and episodic ataxias are often caused by mutations in genes related to cell membrane and synaptic function. Despite the exponential increase in publications of genetically confirmed cases, management remains largely clinical based on non-systematic evidence. Areas covered: The authors provide a historical and clinical review of the main types of paroxysmal dyskinesias and episodic ataxias, with recommendations for diagnosis and management of patients suffering from these conditions. Expert opinion: After secondary paroxysmal dyskinesias, the most common paroxysmal movement disorders are likely to be PRRT2-associated paroxysmal kinesigenic dyskinesias, which respond well to small doses of carbamazepine, and episodic ataxia type 2, which often responds to acetazolamide. Familial paroxysmal non-kinesigenic dyskinesias are largely caused by mutations in PNKD and have poor response to therapy but improve with age. Exercise-induced dyskinesias are genetically heterogeneous, caused by disorders of glucose transport, mitochondrial function, dopaminergic pathways or neurodegenerative conditions amongst others. GNAO1 and ADCY5 mutations can also cause paroxysmal movement disorders, often in the context of ongoing motor symptoms. Although a therapeutic trial is justified for classic cases and in limited resource settings, genetic testing may help direct initial or rescue therapy. Deep brain stimulation may be an option for severe cases.
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Affiliation(s)
- Claudio M De Gusmao
- Department of Neurology, Harvard Medical School, Boston Children's Hospital , Boston , MA , USA.,Department of Neurology, Universidade Estadual de Campinas (UNICAMP) , São Paulo , Brazil
| | - Laura Silveira-Moriyama
- Department of Neurology, Universidade Estadual de Campinas (UNICAMP) , São Paulo , Brazil.,Education Unit, UCL Institute of Neurology, University College London , London , UK.,Department of Neurology, Hospital Bairral, Fundação Espírita Américo Bairral , Itapira , Brazil
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23
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Abstract
PURPOSE OF REVIEW Recent advancements in next-generation sequencing (NGS) have enabled techniques such as whole exome sequencing (WES) and whole genome sequencing (WGS) to be used to study paroxysmal movement disorders (PMDs). This review summarizes how the recent genetic advances have altered our understanding of the pathophysiology and treatment of the PMDs. Recently described disease entities are also discussed. RECENT FINDINGS With the recognition of the phenotypic and genotypic heterogeneity that occurs amongst the PMDs, an increasing number of gene mutations are now implicated to cause the disorders. PMDs can also occur as part of a complex phenotype. The increasing complexity of PMDs challenges the way we view and classify them. The identification of new causative genes and their genotype-phenotype correlation will shed more light on the underlying pathophysiology and will facilitate development of genetic testing guidelines and identification of novel drug targets for PMDs.
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Affiliation(s)
- Zheyu Xu
- Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Che-Kang Lim
- Department of Clinical Translational Research, Singapore General Hospital, Bukit Merah, Singapore, Singapore
- Division of Clinical Immunology and Transfusion Medicine, Department of Laboratory Medicine, Karolinska Institute, Solna, Sweden
| | - Louis C S Tan
- Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
- Duke-NUS Medical School, 8 College Rd, Singapore, 169857, Singapore
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
- Duke-NUS Medical School, 8 College Rd, Singapore, 169857, Singapore.
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24
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Messana T, Russo A, Vergaro R, Boni A, Santucci M, Pini A. Glucose Transporter Type 1 Deficiency Syndrome: Developmental Delay and Early-Onset Ataxia in a Novel Mutation of the SLC2A1 Gene. J Pediatr Neurosci 2019; 13:496-499. [PMID: 30937099 PMCID: PMC6413611 DOI: 10.4103/jpn.jpn_169_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucose transporter type 1 deficiency syndrome (GLUT1-DS) was first described by De Vivo in 1991, and the classic clinical manifestations include infantile epilepsy, developmental delay, and acquired microcephaly. A neurological complex disorder including elements of hypotonia, spasticity, ataxia, and dystonia can frequently be present. GLUT1-DS is an inborn error of metabolism caused by impaired glucose transport through blood–brain barrier in the majority of patients because of mutation of solute carrier family 2 (facilitated glucose transporter) member 1 gene (SLC2A1), encoding the transporter protein. We report a 6-year-old girl with GLUT1-DS, which is caused by a novel heterozygous variant c.109dupC of the SLC2A1 gene. The dominating clinical features were ataxia, epilepsy started at 4 years, acquired microcephaly, and mild intellectual disability. Treatment with ketogenic diet showed clinical improvement with the reduction of ataxia and seizure control in a 10-month follow-up period.
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Affiliation(s)
- Tullio Messana
- Child Neurology and Psychiatry Unit, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Angelo Russo
- Child Neurology and Psychiatry Unit, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Raffaella Vergaro
- Child Neurology and Psychiatry Unit, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Antonella Boni
- Child Neurology and Psychiatry Unit, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Margherita Santucci
- Child Neurology and Psychiatry Unit, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Antonella Pini
- Child Neurology and Psychiatry Unit, IRCCS Institute of Neurological Sciences, Bologna, Italy
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25
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Abstract
Glucose, a major source of energy for all cells, is transported into cells with the help of glucose transporters (GLUTs). These transporters are of two types, namely sodium-dependent GLUTs and facilitative GLUTs. These transporters are present in a tissue-specific pattern and have substrate specificity. Among these transporters, GLUT1 (facilitative GLUT) is present ubiquitously on all tissues of the body and helps in the basal uptake of glucose. GLUT1 is known to have many physiological functions in the body from the time of implantation of an embryo and is also seen associated with pathologies, including cancers. This review mainly focuses on GLUT1 in physiological and pathological conditions and the recent advances related to its role in cancer development and applications in cancer therapeutics.
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Affiliation(s)
- Sindhuri Pragallapati
- Department of Oral Pathology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
| | - Ravikanth Manyam
- Head of the Department, Department of Oral Pathology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
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26
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Ebrahimi‐Fakhari D, Van Karnebeek C, Münchau A. Movement Disorders in Treatable Inborn Errors of Metabolism. Mov Disord 2018; 34:598-613. [DOI: 10.1002/mds.27568] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/30/2018] [Accepted: 10/25/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Darius Ebrahimi‐Fakhari
- Department of Neurology, Boston Children's HospitalHarvard Medical School Boston Massachusetts USA
| | - Clara Van Karnebeek
- Departments of Pediatrics and Clinical GeneticsAmsterdam University Medical Centres Amsterdam The Netherlands
| | - Alexander Münchau
- Department of Pediatric and Adult Movement Disorders and Neuropsychiatry, Institute of NeurogeneticsUniversity of Lübeck Lübeck Germany
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27
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Sharif Y, Jumah F, Coplan L, Krosser A, Sharif K, Tubbs RS. Blood brain barrier: A review of its anatomy and physiology in health and disease. Clin Anat 2018; 31:812-823. [PMID: 29637627 DOI: 10.1002/ca.23083] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/03/2018] [Indexed: 12/14/2022]
Abstract
The blood-brain barrier (BBB) is the principal regulator of transport of molecules and cells into and out of the central nervous system (CNS). It comprises endothelial cells, pericytes, immune cells, astrocytes, and basement membrane, collectively known as the neurovascular unit. The development of the barrier involves many complex pathways from all the progenitors of the neurovascular unit, but the timing of its formation is not entirely known. The coordinated activities of all the components of the neurovascular unit and other tissues ensure that materials required for growth and maintenance are allowed into the CNS while extraneous ones are excluded. This review summarizes current knowledge of the anatomy, development, and physiology of the BBB, and alterations that occur in disease conditions. Clin. Anat. 31:812-823, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Yousra Sharif
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Fareed Jumah
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Louis Coplan
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Alec Krosser
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Kassem Sharif
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - R Shane Tubbs
- Department of Anatomical Sciences, St. George's University, Grenada.,Seattle Science Foundation, Seattle, Washington
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28
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Flatt JF, Bruce LJ. The Molecular Basis for Altered Cation Permeability in Hereditary Stomatocytic Human Red Blood Cells. Front Physiol 2018; 9:367. [PMID: 29713289 PMCID: PMC5911802 DOI: 10.3389/fphys.2018.00367] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/27/2018] [Indexed: 11/20/2022] Open
Abstract
Normal human RBCs have a very low basal permeability (leak) to cations, which is continuously corrected by the Na,K-ATPase. The leak is temperature-dependent, and this temperature dependence has been evaluated in the presence of inhibitors to exclude the activity of the Na,K-ATPase and NaK2Cl transporter. The severity of the RBC cation leak is altered in various conditions, most notably the hereditary stomatocytosis group of conditions. Pedigrees within this group have been classified into distinct phenotypes according to various factors, including the severity and temperature-dependence of the cation leak. As recent breakthroughs have provided more information regarding the molecular basis of hereditary stomatocytosis, it has become clear that these phenotypes elegantly segregate with distinct genetic backgrounds. The cryohydrocytosis phenotype, including South-east Asian Ovalocytosis, results from mutations in SLC4A1, and the very rare condition, stomatin-deficient cryohydrocytosis, is caused by mutations in SLC2A1. Mutations in RHAG cause the very leaky condition over-hydrated stomatocytosis, and mutations in ABCB6 result in familial pseudohyperkalemia. All of the above are large multi-spanning membrane proteins and the mutations may either modify the structure of these proteins, resulting in formation of a cation pore, or otherwise disrupt the membrane to allow unregulated cation movement across the membrane. More recently mutations have been found in two RBC cation channels, PIEZO1 and KCNN4, which result in dehydrated stomatocytosis. These mutations alter the activation and deactivation kinetics of these channels, leading to increased opening and allowing greater cation fluxes than in wild type.
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Affiliation(s)
- Joanna F Flatt
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, United Kingdom
| | - Lesley J Bruce
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, United Kingdom
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29
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Di Vito L, Licchetta L, Pippucci T, Baldassari S, Stipa C, Mostacci B, Alvisi L, Tinuper P, Bisulli F. Phenotype variability of GLUT1 deficiency syndrome: Description of a case series with novel SLC2A1 gene mutations. Epilepsy Behav 2018; 79:169-173. [PMID: 29306089 DOI: 10.1016/j.yebeh.2017.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/13/2017] [Accepted: 12/15/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Lidia Di Vito
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy
| | - Laura Licchetta
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
| | - Tommaso Pippucci
- U.O. Medical Genetics, Sant'Orsola-Malpighi University Hospital, Bologna, Italy.
| | - Sara Baldassari
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy.
| | - Carlotta Stipa
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Barbara Mostacci
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy.
| | - Lara Alvisi
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
| | - Paolo Tinuper
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
| | - Francesca Bisulli
- IRCCS Institute of Neurological Sciences, Via Altura 3, 40137 Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
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30
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Shin J, Paek KY, Ivshina M, Stackpole EE, Richter JD. Essential role for non-canonical poly(A) polymerase GLD4 in cytoplasmic polyadenylation and carbohydrate metabolism. Nucleic Acids Res 2017; 45:6793-6804. [PMID: 28383716 PMCID: PMC5499868 DOI: 10.1093/nar/gkx239] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/30/2017] [Indexed: 11/16/2022] Open
Abstract
Regulation of gene expression at the level of cytoplasmic polyadenylation is important for many biological phenomena including cell cycle progression, mitochondrial respiration, and learning and memory. GLD4 is one of the non-canonical poly(A) polymerases that regulates cytoplasmic polyadenylation-induced translation, but its target mRNAs and role in cellular physiology is not well known. To assess the full panoply of mRNAs whose polyadenylation is controlled by GLD4, we performed an unbiased whole genome-wide screen using poy(U) chromatography and thermal elution. We identified hundreds of mRNAs regulated by GLD4, several of which are involved in carbohydrate metabolism including GLUT1, a major glucose transporter. Depletion of GLD4 not only reduced GLUT1 poly(A) tail length, but also GLUT1 protein. GLD4-mediated translational control of GLUT1 mRNA is dependent of an RNA binding protein, CPEB1, and its binding elements in the 3΄ UTR. Through regulating GLUT1 level, GLD4 affects glucose uptake into cells and lactate levels. Moreover, GLD4 depletion impairs glucose deprivation-induced GLUT1 up-regulation. In addition, we found that GLD4 affects glucose-dependent cellular phenotypes such as migration and invasion in glioblastoma cells. Our observations delineate a novel post-transcriptional regulatory network involving carbohydrate metabolism and glucose homeostasis mediated by GLD4.
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Affiliation(s)
- Jihae Shin
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ki Young Paek
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Maria Ivshina
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Emily E Stackpole
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
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31
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Pardeshi R, Bolshette N, Gadhave K, Ahire A, Ahmed S, Cassano T, Gupta VB, Lahkar M. Insulin signaling: An opportunistic target to minify the risk of Alzheimer's disease. Psychoneuroendocrinology 2017. [PMID: 28624654 DOI: 10.1016/j.psyneuen.2017.05.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is progressive neurodegenerative disorder characterized by accumulation of senile plaques, neurofibrillary tangles (NFT) and neurodegeneration. The diabetes mellitus (DM) is one of the risk factors for AD pathogenesis by impairment in insulin signaling and glucose metabolism in central as well as peripheral system. Insulin resistance, impaired glucose and lipid metabolism are leading to the Aβ (Aβ) aggregation, Tau phosphorylation, mitochondrial dysfunction, oxidative stress, protein misfolding, memory impairment and also mark over Aβ transport through central to peripheral and vice versa. Several pathways, like enzymatic degradation of Aβ, forkhead box protein O1 (FOXO) signaling, insulin signaling shared common pathological mechanism for both AD and DM. Recent evidence showed that hyperinsulinemia and hyperglycemia affect the onset and progression of AD differently. Some researchers have suggested that hyperglycemia influences vascular tone, while hyperinsulinemia may underlie mitochondrial deficit. The objective of this review is to determine whether existing evidence supports the concept that impairment in insulin signaling and glucose metabolism play an important role in pathogenesis of AD. In the first part of this review, we tried to explain the interconnecting link between AD and DM, whereas the second part includes more information on insulin resistance and its involvement in AD pathogenesis. In the final part of this review, we have focused more toward the AD treatment by targeting insulin signaling like anti-diabetic, antioxidant, nutraceuticals and dietary supplements. To date, more researches should be done in this field in order to explore the pathways in insulin signaling, which might ameliorate the treatment options and reduce the risk of AD due to DM.
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Affiliation(s)
- Rohit Pardeshi
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India
| | - Nityanand Bolshette
- Institutional Level Biotech hub (IBT hub), Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India
| | - Kundlik Gadhave
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India
| | - Ashutosh Ahire
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India
| | - Sahabuddin Ahmed
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, University of Foggia, Via Luigi Pinto, c/o Ospedali Riuniti, 71122 Foggia, Italy
| | - Veer Bala Gupta
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith-Cowan University, Joondalup, WA 6027, Australia
| | - Mangala Lahkar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India; Institutional Level Biotech hub (IBT hub), Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India; Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Gauhati Medical College, Guwahati 781032, Assam, India.
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32
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Szablewski L. Glucose Transporters in Brain: In Health and in Alzheimer’s Disease. J Alzheimers Dis 2016; 55:1307-1320. [DOI: 10.3233/jad-160841] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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33
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Patel J, Mercimek-Mahmutoglu S. Epileptic Encephalopathy in Childhood: A Stepwise Approach for Identification of Underlying Genetic Causes. Indian J Pediatr 2016; 83:1164-74. [PMID: 26821542 DOI: 10.1007/s12098-015-1979-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 12/02/2015] [Indexed: 01/29/2023]
Abstract
Epilepsy is one of the most common neurological disorders in childhood. Epilepsy associated with global developmental delay and cognitive dysfunction is defined as epileptic encephalopathy. Certain inherited metabolic disorders presenting with epileptic encephalopathy can be treated with disease specific diet, vitamin, amino acid or cofactor supplementations. In those disorders, disease specific therapy is successful to achieve good seizure control and improve long-term neurodevelopmental outcome. For this reason, intractable epilepsy with global developmental delay or history of developmental regression warrants detailed metabolic investigations for the possibility of an underlying treatable inherited metabolic disorder, which should be undertaken as first line investigations. An underlying genetic etiology in epileptic encephalopathy has been supported by recent studies such as array comparative genomic hybridization, targeted next generation sequencing panels, whole exome and whole genome sequencing. These studies report a diagnostic yield up to 70%, depending on the applied genetic testing as well as number of patients enrolled. In patients with epileptic encephalopathy, a stepwise approach for diagnostic work-up will help to diagnose treatable inherited metabolic disorders quickly. Application of detailed genetic investigations such as targeted next generation sequencing as second line and whole exome sequencing as third line testing will diagnose underlying genetic disease which will help for genetic counseling as well as guide for prenatal diagnosis. Knowledge of underlying genetic cause will provide novel insights into the pathogenesis of epileptic encephalopathy and pave the ground towards the development of targeted neuroprotective treatment strategies to improve the health outcome of children with epileptic encephalopathy.
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Affiliation(s)
- Jaina Patel
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
| | - Saadet Mercimek-Mahmutoglu
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada. .,Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
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34
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De Giorgis V, Varesio C, Baldassari C, Piazza E, Olivotto S, Macasaet J, Balottin U, Veggiotti P. Atypical Manifestations in Glut1 Deficiency Syndrome. J Child Neurol 2016; 31:1174-80. [PMID: 27250207 DOI: 10.1177/0883073816650033] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 03/27/2016] [Indexed: 11/17/2022]
Abstract
Glucose transporter type 1 deficiency syndrome is a genetically determined, treatable, neurologic disorder that is caused by an insufficient transport of glucose into the brain. It is caused by a mutation in the SCL2A1 gene, which is so far the only known to be associated with this condition. Glucose transporter type 1 deficiency syndrome consists of a wide clinical spectrum that usually presents with cognitive impairment, epilepsy, paroxysmal exercise-induced dyskinesia, acquired microcephaly, hemolytic anemia, gait disturbance, and dyspraxia in different combinations. However, there are other clinical manifestations that we consider equally peculiar but that have so far been poorly described in literature. In this review, supported by a video contribution, we will accurately describe this type of clinical manifestation such as oculogyric crises, weakness, paroxysmal kinesigenic and nonkinesigenic dyskinesia in order to provide an additional instrument for a correct, rapid diagnosis.
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Affiliation(s)
- V De Giorgis
- Brain and Behaviour Department, University of Pavia, Pavia, Italy
| | - C Varesio
- Department of Child Neurology and Psychiatry, "C. Mondino" National Neurological Institute, Pavia, Italy
| | - C Baldassari
- Department of Child Neurology and Psychiatry, "C. Mondino" National Neurological Institute, Pavia, Italy
| | - E Piazza
- Brain and Behaviour Department, University of Pavia, Pavia, Italy
| | - S Olivotto
- Department of Child Neurology and Psychiatry, "C. Mondino" National Neurological Institute, Pavia, Italy
| | - J Macasaet
- Department of Neurosciences, Makati Medical Center, Manila, Philippines
| | - U Balottin
- Brain and Behaviour Department, University of Pavia, Pavia, Italy Department of Child Neurology and Psychiatry, "C. Mondino" National Neurological Institute, Pavia, Italy
| | - P Veggiotti
- Brain and Behaviour Department, University of Pavia, Pavia, Italy Department of Child Neurology and Psychiatry, "C. Mondino" National Neurological Institute, Pavia, Italy
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35
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Abstract
Vitamin-dependent epilepsies and multiple metabolic epilepsies are amenable to treatment that markedly improves the disease course. Knowledge of these amenably treatable severe pediatric epilepsies allows for early identification, testing, and treatment. These disorders present with various phenotypes, including early onset epileptic encephalopathy (refractory neonatal seizures, early myoclonic encephalopathy, and early infantile epileptic encephalopathy), infantile spasms, or mixed generalized seizure types in infancy, childhood, or even adolescence and adulthood. The disorders are presented as vitamin responsive epilepsies such as pyridoxine, pyridoxal-5-phosphate, folinic acid, and biotin; transportopathies like GLUT-1, cerebral folate deficiency, and biotin thiamine responsive disorder; amino and organic acidopathies including serine synthesis defects, creatine synthesis disorders, molybdenum cofactor deficiency, and cobalamin deficiencies; mitochondrial disorders; urea cycle disorders; neurotransmitter defects; and disorders of glucose homeostasis. In each case, targeted intervention directed toward the underlying metabolic pathophysiology affords for the opportunity to significantly effect the outcome and prognosis of an otherwise severe pediatric epilepsy.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA.
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36
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Fu X, Zhang G, Liu R, Wei J, Zhang-Negrerie D, Jian X, Gao Q. Mechanistic Study of Human Glucose Transport Mediated by GLUT1. J Chem Inf Model 2016; 56:517-26. [PMID: 26821218 DOI: 10.1021/acs.jcim.5b00597] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The glucose transporter 1 (GLUT1) belongs to the major facilitator superfamily (MFS) and is responsible for the constant uptake of glucose. However, the molecular mechanism of sugar transport remains obscure. In this study, homology modeling and molecular dynamics (MD) simulations in lipid bilayers were performed to investigate the combination of the alternate and multisite transport mechanism of glucose with GLUT1 in atomic detail. To explore the substrate recognition mechanism, the outward-open state human GLUT1 homology model was generated based on the template of xylose transporter XylE (PDB ID: 4GBZ), which shares up to 29% sequence identity and 49% similarity with GLUT1. Through the MD simulation study of glucose across lipid bilayer with both the outward-open GLUT1 and the GLUT1 inward-open crystal structure, we investigated six different conformational states and identified four key binding sites in both exofacial and endofacial loops that are essential for glucose recognition and transport. The study further revealed that four flexible gates consisting of W65/Y292/Y293-M420/TM10b-W388 might play important roles in the transport cycle. The study showed that some side chains close to the central ligand binding site underwent larger position changes. These conformational interchanges formed gated networks within an S-shaped central channel that permitted staged ligand diffusion across the transporter. This study provides new inroads for the understanding of GLUT1 ligand recognition paradigm and configurational features which are important for molecular, structural, and physiological research of the MFS members, especially for GLUT1-targeted drug design and discovery.
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Affiliation(s)
- Xuegang Fu
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University , Tianjin, 300072, P. R. China
| | - Gang Zhang
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University , Tianjin, 300072, P. R. China
| | - Ran Liu
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University , Tianjin, 300072, P. R. China
| | - Jing Wei
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University , Tianjin, 300072, P. R. China
| | - Daisy Zhang-Negrerie
- Concordia International School , 999 Mingyue Road, Shanghai, 201206, P. R. China
| | - Xiaodong Jian
- National Supercomputing Center in Tianjin , TEDA Service Outsourcing Industrial Park, Binhai New Area, Tianjin, 300457, P. R. China
| | - Qingzhi Gao
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University , Tianjin, 300072, P. R. China.,Tianjin University Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, P. R. China
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Glucose Transporters at the Blood-Brain Barrier: Function, Regulation and Gateways for Drug Delivery. Mol Neurobiol 2016; 54:1046-1077. [PMID: 26801191 DOI: 10.1007/s12035-015-9672-6] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/17/2015] [Indexed: 12/31/2022]
Abstract
Glucose transporters (GLUTs) at the blood-brain barrier maintain the continuous high glucose and energy demands of the brain. They also act as therapeutic targets and provide routes of entry for drug delivery to the brain and central nervous system for treatment of neurological and neurovascular conditions and brain tumours. This article first describes the distribution, function and regulation of glucose transporters at the blood-brain barrier, the major ones being the sodium-independent facilitative transporters GLUT1 and GLUT3. Other GLUTs and sodium-dependent transporters (SGLTs) have also been identified at lower levels and under various physiological conditions. It then considers the effects on glucose transporter expression and distribution of hypoglycemia and hyperglycemia associated with diabetes and oxygen/glucose deprivation associated with cerebral ischemia. A reduction in glucose transporters at the blood-brain barrier that occurs before the onset of the main pathophysiological changes and symptoms of Alzheimer's disease is a potential causative effect in the vascular hypothesis of the disease. Mutations in glucose transporters, notably those identified in GLUT1 deficiency syndrome, and some recreational drug compounds also alter the expression and/or activity of glucose transporters at the blood-brain barrier. Approaches for drug delivery across the blood-brain barrier include the pro-drug strategy whereby drug molecules are conjugated to glucose transporter substrates or encapsulated in nano-enabled delivery systems (e.g. liposomes, micelles, nanoparticles) that are functionalised to target glucose transporters. Finally, the continuous development of blood-brain barrier in vitro models is important for studying glucose transporter function, effects of disease conditions and interactions with drugs and xenobiotics.
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Nakamura S, Osaka H, Muramatsu S, Aoki S, Jimbo EF, Yamagata T. Mutational and functional analysis of Glucose transporter I deficiency syndrome. Mol Genet Metab 2015; 116:157-62. [PMID: 26304067 DOI: 10.1016/j.ymgme.2015.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/09/2015] [Accepted: 08/09/2015] [Indexed: 01/11/2023]
Abstract
OBJECTIVE We investigated a correlation between a mutation in the SLC2A1 gene and functional disorders in Glucose transporter I deficiency syndrome (GLUT1DS). METHODS We performed direct sequence analysis of SLC2A1 in a severe GLUT1DS patient and identified a novel frame shift mutation, c.906_907insG, p.V303fs. We created a plasmid vector carrying the c.906_907insG mutation, as well as A405D or R333W in the SLC2A1, which are found in patients with mild and moderate GLUT1DS severity, respectively. We transiently expressed these mutants and wild type SLC2A1 plasmids in a human embryonic kidney cell line (HEK293), and performed immunoblotting, immunofluorescence, and enzymatic photometric 2-deoxyglucose (2DG) uptake assays. RESULTS GLUT1 was not detected after transient expression of the SLC2A1 plasmid carrying c.906_907insG by either immunoblotting or immunofluorescence. The degree of glucose transport reduction as determined by enzymatic photometric 2DG assay uptake correlated with disease severity. CONCLUSIONS Enzymatic photometric 2DG uptake study appears to be a suitable functional assay to predict the effect of SLC2A1 mutations on GLUT1 transport.
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Affiliation(s)
- Sachie Nakamura
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
| | - Hitoshi Osaka
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan.
| | - Shinichi Muramatsu
- Division of Neurology, Jichi Medical University, Tochigi, Japan; Center for Gene and Cell Therapy, The Institute of Medical Science, The University of Tokyo, Japan
| | - Shiho Aoki
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
| | - Eriko F Jimbo
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
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Keaney J, Campbell M. The dynamic blood-brain barrier. FEBS J 2015; 282:4067-79. [DOI: 10.1111/febs.13412] [Citation(s) in RCA: 338] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/20/2015] [Accepted: 08/12/2015] [Indexed: 01/19/2023]
Affiliation(s)
- James Keaney
- Smurfit Institute of Genetics; Trinity College Dublin; Ireland
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Nationwide survey of glucose transporter-1 deficiency syndrome (GLUT-1DS) in Japan. Brain Dev 2015; 37:780-9. [PMID: 25487684 DOI: 10.1016/j.braindev.2014.11.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 10/20/2014] [Accepted: 11/20/2014] [Indexed: 11/22/2022]
Abstract
OBJECTIVES We conducted a nationwide survey of glucose transporter type-1 deficiency syndrome (GLUT-1DS) in Japan in order to clarify its incidence as well as clinical and laboratory information. SUBJECTS AND METHODS A questionnaire to survey the number of genetically and clinically confirmed cases of GLUT-1DS was sent to 1018 board-certified pediatric neurologists, which resulted in 57 patients being reported. We obtained the clinical and laboratory data of 33 patients through a secondary questionnaire. RESULTS The age of the 33 patients (male: 15, female: 18) at the time of the study ranged between 3 and 35 years (mean: 13.5 years). The age of these patients at the onset of initial neurological symptoms ranged between the neonatal period and 48 months (mean: 9.4 months). GLUT-1DS was diagnosed at a mean age of 8.4 years (range: 1 year to 33 years). The initial symptom was convulsive seizures, which occurred in 15 cases, and was followed by abnormal eye movements in 7 cases and apneic or cyanotic attacks in 4 cases. The latter two symptoms most frequently occurred early in infancy. Thirty-two patients (97%) exhibited some type of epileptic seizure. Neurological findings revealed that most patients had muscle hypotonia, cerebellar ataxia, dystonia, and spastic paralysis. Mild to severe mental retardation was detected in all 33 cases. Furthermore, paroxysmal episodes of ataxia, dystonia/dyskinesia, and motor paralysis were described in approximately 1/3 of all patients. The factors that frequently aggravated these events were hunger, exercise, fever, and fatigue, in that order. The mean CSF/blood glucose ratio was 0.36 (0.28-0.48). Pathological mutations in the SLC2A1 gene were identified in 28 out of 32 cases (87.5%). CONCLUSION The results described herein provided an insight into the early diagnosis of GLUT1-DS, including unexplained paroxysmal abnormal eye movements, apneic/cyanotic attacks, and convulsive seizures in infancy, as well as uncommon paroxysmal events (ataxia, atonia, and motor paralysis) in childhood.
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From splitting GLUT1 deficiency syndromes to overlapping phenotypes. Eur J Med Genet 2015; 58:443-54. [PMID: 26193382 DOI: 10.1016/j.ejmg.2015.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/18/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a rare genetic disorder due to mutations or deletions in SLC2A1, resulting in impaired glucose uptake through the blood brain barrier. The classic phenotype includes pharmacoresistant epilepsy, intellectual deficiency, microcephaly and complex movement disorders, with hypoglycorrhachia, but milder phenotypes have been described (carbohydrate-responsive phenotype, dystonia and ataxia without epilepsy, paroxysmal exertion-induced dystonia). The aim of our study was to provide a comprehensive overview of GLUT1DS in a French cohort. METHODS 265 patients were referred to the French national laboratory for molecular screening between July 2006 and January 2012. Mutations in SLC2A1 were detected in 58 patients, with detailed clinical data available in 24, including clinical features with a focus on their epileptic pattern and electroencephalographic findings, biochemical findings and neuroimaging findings. RESULTS 53 point mutations and 5 deletions in SLC2A1 were identified. Most patients (87.5%) exhibited classic phenotype with intellectual deficiency (41.7%), epilepsy (75%) or movement disorder (29%) as initial symptoms at a medium age of 7.5 months, but diagnostic was delayed in most cases (median age at diagnostic 8 years 5 months). Sensitivity to fasting or exertion in combination with those 3 main symptoms were the main differences between mutated and negative patients (p < 0.001). Patients with myoclonic seizures (52%) evolved with more severe intellectual deficiency and movement disorders compared with those with Early Onset Absence Epilepsy (38%). Three patients evolved from a classic phenotype during early childhood to a movement disorder predominant phenotype at a late childhood/adulthood. CONCLUSIONS Our data confirm that the classic phenotype is the most frequent in GLUT1DS. Myoclonic seizures are a distinctive feature of severe forms. However a great variability among patients and overlapping through life from milder classic phenotype to paroxysmal-prominent- movement-disorder phenotype are possible, thus making it difficult to identify definite genotype-phenotype correlations.
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Raja M, Kinne RKH. Pathogenic mutations causing glucose transport defects in GLUT1 transporter: The role of intermolecular forces in protein structure-function. Biophys Chem 2015; 200-201:9-17. [PMID: 25863194 DOI: 10.1016/j.bpc.2015.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/12/2015] [Accepted: 03/17/2015] [Indexed: 12/14/2022]
Abstract
Two families of glucose transporter - the Na(+)-dependent glucose cotransporter-1 (SGLT family) and the facilitated diffusion glucose transporter family (GLUT family) - play a crucial role in the translocation of glucose across the epithelial cell membrane. How genetic mutations cause life-threatening diseases like GLUT1-deficiency syndrome (GLUT1-DS) is not well understood. In this review, we have combined previous functional data with our in silico analyses of the bacterial homologue of GLUT members, XylE (an outward-facing, partly occluded conformation) and previously proposed GLUT1 homology model (an inward-facing conformation). A variety of native and mutant side chain interactions were modeled to highlight the potential roles of mutations in destabilizing protein-protein interaction hence triggering structural and functional defects. This study sets the stage for future studies of the structural properties that mediate GLUT1 dysfunction and further suggests that both SGLT and GLUT families share conserved domains that stabilize the transporter structure/function via a similar mechanism.
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Affiliation(s)
- Mobeen Raja
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany; Molecular Structure and Function, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada.
| | - Rolf K H Kinne
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
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Abstract
Epileptic encephalopathies represent a group of devastating epileptic disorders that occur early in life and are often characterized by pharmaco-resistant epilepsy, persistent severe electroencephalographic abnormalities, and cognitive dysfunction or decline. Next generation sequencing technologies have increased the speed of gene discovery tremendously. Whereas ion channel genes were long considered to be the only significant group of genes implicated in the genetic epilepsies, a growing number of non-ion-channel genes are now being identified. As a subgroup of the genetically mediated epilepsies, epileptic encephalopathies are complex and heterogeneous disorders, making diagnosis and treatment decisions difficult. Recent exome sequencing data suggest that mutations causing epileptic encephalopathies are often sporadic, typically resulting from de novo dominant mutations in a single autosomal gene, although inherited autosomal recessive and X-linked forms also exist. In this review we provide a summary of the key features of several early- and mid-childhood onset epileptic encephalopathies including Ohtahara syndrome, Dravet syndrome, Infantile spasms and Lennox Gastaut syndrome. We review the recent next generation sequencing findings that may impact treatment choices. We also describe the use of conventional and newer anti-epileptic and hormonal medications in the various syndromes based on their genetic profile. At a biological level, developments in cellular reprogramming and genome editing represent a new direction in modeling these pediatric epilepsies and could be used in the development of novel and repurposed therapies.
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Affiliation(s)
- Sahar Esmaeeli Nieh
- Departments of Neurology and Pediatrics, University of California, San Francisco, CA USA
| | - Elliott H. Sherr
- Departments of Neurology and Pediatrics, University of California, San Francisco, CA USA
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Abstract
GLUT-1-deficiency syndrome (GLUT1-DS; OMIM 606777) is a treatable metabolic disorder caused by a mutation of SLC2A1 gene. The functional deficiency of the GLUT1 protein leads to an impaired glucose transport into the brain, resulting in neurologic disorders.We report on a 6-month-old boy with preprandial malaises who was treated monthly by a sorcerer because of a permanent acetonemic odor. He subsequently developed pharmaco-resistant seizures with microcephaly and motor abnormalities. Metabolic explorations were unremarkable except for a fasting glucose test which revealed an abnormal increase of blood ketone bodies. At the age of 35 months, GLUT1-DS was diagnosed based on hypoglycorrhachia with a decreased CSF to blood glucose ratio, and subsequent direct sequencing of the SLC2A1 gene revealed a de novo heterozygous mutation, c.349A>T (p.Lys117X) on exon 4. It was noteworthy that the patient adapted to the deficient cerebral glucose transport by permanent ketone body production since early life. Excessive ketone body production in this patient provided an alternative energy substrate for his brain. We suggest a cerebral metabolic adaptation with upregulation of monocarboxylic acid transporter proteins (MCT1) at the blood-brain barrier provoked by neuroglycopenia and allowing ketone body utilization by the brain. This case illustrates that GLUT1-DS should be considered in the differential diagnosis of permanent ketosis.
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Erro R, Sheerin UM, Bhatia KP. Paroxysmal dyskinesias revisited: a review of 500 genetically proven cases and a new classification. Mov Disord 2014; 29:1108-16. [PMID: 24963779 DOI: 10.1002/mds.25933] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 04/30/2014] [Accepted: 05/13/2014] [Indexed: 12/31/2022] Open
Abstract
Paroxysmal movement disorders are a heterogeneous group of conditions manifesting as episodic dyskinesia with sudden onset and lasting a variable duration. Based on the difference of precipitating factors, three forms are clearly recognized, namely, paroxysmal kinesigenic (PKD), non-kinesigenic (PNKD), and exercise induced (PED). The elucidation of the genetic cause of various forms of paroxysmal dyskinesia has led to better clinical definitions based on genotype-phenotype correlations in the familial forms. However, it has been increasingly recognized that (1) there is a marked pleiotropy of mutations in such genes with still expanding clinical spectra; and (2) not all patients clinically presenting with either PKD, PNKD, or PED have mutations in these genes. We aimed to review the clinical features of 500 genetically proven cases published to date. Based on our results, it is clear that there is not a complete phenotypic-genotypic correlation, and therefore we suggest an algorithm to lead the genetic analyses. Given the fact that the reliability of current clinical categorization is not entirely valid, we further propose a novel classification for paroxysmal dyskinesias, which takes into account the recent genetic discoveries in this field.
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Affiliation(s)
- Roberto Erro
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Institute of Neurology, London, United Kingdom
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Veggiotti P, De Giorgis V. Dietary Treatments and New Therapeutic Perspective in GLUT1 Deficiency Syndrome. Curr Treat Options Neurol 2014; 16:291. [PMID: 24634059 DOI: 10.1007/s11940-014-0291-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OPINION STATEMENT GLUT1 deficiency syndrome (GLUT1DS) results from impaired glucose transport into the brain: awareness of its wide phenotypic spectrum is a prerequisite in order to ensure an early diagnosis, treating the patients is the subsequent challenge to allow prompt compensation for the brain's lack of fuel. The ketogenic diet (KD) plays a primary role in the treatment of GLUT1DS because it provides ketone bodies as an alternative source to meet the demands of energy of the brain. Therefore, we recommend early initiation of the KD based on the assumption that early diagnosis and treatment improves the long term neurological outcome: the classic KD (4:1 or 3:1) at the present time is the most proven and effective in GLUT1DS. A KD should be continued at least until adolescence, although there are reports of good tolerability even in adulthood, possibly with a less rigorous ratio; in our experience seizure and movement disorder control can be achieved by a 2:1 ketogenic ratio but the relationship between ketosis and neurodevelopmental outcome remains undetermined. Other types of KDs can, therefore, be considered. The Modified Atkins diet, for example, is also well tolerated and provides effective symptom control; furthermore, this diet has the advantage of being easy to prepare and more palatable, which are important requirements for good compliance. Nevertheless, about 20 % of these patients have compliance trouble or the same diet loses its effectiveness over time; for these reasons, new therapeutic strategies are currently under investigation but further studies on pathophysiological mechanisms and potential effects of novel "diets" or "therapies" are needed for this new pathology.
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Affiliation(s)
- Pierangelo Veggiotti
- Department of Child Neurology and Psychiatry C. Mondino National Neurological Institute, Via Mondino, 2, 27100, Pavia, Italy,
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Tzadok M, Nissenkorn A, Porper K, Matot I, Marcu S, Anikster Y, Menascu S, Bercovich D, Ben Zeev B. The many faces of Glut1 deficiency syndrome. J Child Neurol 2014; 29:349-59. [PMID: 23340081 DOI: 10.1177/0883073812471718] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glucose transporter protein type 1 deficiency syndrome is a metabolic disorder manifesting as cognitive impairment, acquired microcephaly, epilepsy, and/or movement disorder caused by mutations in the SLC2A1 gene. We describe a cohort of isolated and familial cases of glucose transporter protein type 1 deficiency syndrome, emphasizing seizure semiology, electroencephalographic (EEG) features, treatment response and mutation pathogenicity. SLC2A1 mutations were detected in 3 sporadic and 4 familial cases. In addition, mutations were identified in 9 clinically unaffected family members in 2 families. The phenotypic spectrum of glucose transporter protein type 1 deficiency is wider than previously recognized, with considerable intra-familial variation. Diagnosis requires either hypoglycorrachia followed by SLC2A1 sequencing or direct gene sequencing. A ketogenic diet should be the first line of treatment, but more flexible diets, like the Atkins modified diet, can also be followed. Carbonic anhydrase inhibitors, such as acetazolamide or zonisamide, can be effective for seizure control.
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Affiliation(s)
- Michal Tzadok
- 1Pediatric Neurology Unit, Edmond and Lily Safra Childern's Hospital, Sheba Medical Center, Tel Hashomer, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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GLUT1 deficiency syndrome: an update. Rev Neurol (Paris) 2013; 170:91-9. [PMID: 24269118 DOI: 10.1016/j.neurol.2013.09.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/01/2013] [Accepted: 09/02/2013] [Indexed: 01/31/2023]
Abstract
INTRODUCTION Glucose transporter type 1 deficiency syndrome is caused by heterozygous, mostly de novo, mutations in the SLC2A1 gene encoding the glucose transporter GLUT1. Mutations in this gene limit brain glucose availability and lead to cerebral energy deficiency. STATE OF THE ART The phenotype is characterized by the variable association of mental retardation, acquired microcephaly, complex motor disorders, and paroxysmal manifestations including seizures and non-epileptic paroxysmal episodes. Clinical severity varies from mild motor dysfunction to severe neurological disability. In patients with mild phenotypes, paroxysmal manifestations may be the sole manifestations of the disease. In particular, the diagnosis should be considered in patients with paroxysmal exercise-induced dyskinesia or with early-onset generalized epilepsy. Low CSF level of glucose, relative to blood level, is the best biochemical clue to the diagnosis although not constantly found. Molecular analysis of the SLC2A1 gene confirms the diagnosis. Ketogenic diet is the cornerstone of the treatment and implicates a close monitoring by a multidisciplinary team including trained dieticians. Non-specific drugs may be used as add-on symptomatic treatments but their effects are often disappointing. CONCLUSION Glucose transporter type 1 deficiency syndrome is likely under diagnosed due to its complex and pleiotropic phenotype. Proper identification of the affected patients is important for clinical practice since the disease is treatable.
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Papetti L, Parisi P, Leuzzi V, Nardecchia F, Nicita F, Ursitti F, Marra F, Paolino MC, Spalice A. Metabolic epilepsy: an update. Brain Dev 2013; 35:827-41. [PMID: 23273990 DOI: 10.1016/j.braindev.2012.11.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/23/2012] [Accepted: 11/25/2012] [Indexed: 10/27/2022]
Abstract
Inborn errors of metabolism comprise a large class of genetic diseases involving disorders of metabolism. Presentation is usually in the neonatal period or infancy but can occur at any time, even in adulthood. Seizures are frequent symptom in inborn errors of metabolism, with no specific seizure types or EEG signatures. The diagnosis of a genetic defect or an inborn error of metabolism often results in requests for a vast array of biochemical and molecular tests leading to an expensive workup. However a specific diagnosis of metabolic disorders in epileptic patients may provide the possibility of specific treatments that can improve seizures. In a few metabolic diseases, epilepsy responds to specific treatments based on diet or supplementation of cofactors (vitamin-responsive epilepsies), but for most of them specific treatment is unfortunately not available, and conventional antiepileptic drugs must be used, often with no satisfactory success. In this review we present an overview of metabolic epilepsies based on various criteria such as treatability, age of onset, seizure type, and pathogenetic background.
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Affiliation(s)
- Laura Papetti
- Department of Pediatrics, Child Neurology Division, Sapienza University of Rome, Italy
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Phenotypic spectrum of glucose transporter type 1 deficiency syndrome (Glut1 DS). Curr Neurol Neurosci Rep 2013; 13:342. [PMID: 23443458 DOI: 10.1007/s11910-013-0342-7] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Glut1 deficiency syndrome (Glut1 DS) was originally described in 1991 as a developmental encephalopathy characterized by infantile onset refractory epilepsy, cognitive impairment, and mixed motor abnormalities including spasticity, ataxia, and dystonia. The clinical condition is caused by impaired glucose transport across the blood brain barrier. The past 5 years have seen a dramatic expansion in the range of clinical syndromes that are recognized to occur with Glut1 DS. In particular, there has been greater recognition of milder phenotypes. Absence epilepsy and other idiopathic generalized epilepsy syndromes may occur with seizure onset in childhood or adulthood. A number of patients present predominantly with movement disorders, sometimes without any accompanying seizures. In particular, paroxysmal exertional dyskinesia is now a well-documented clinical feature that occurs in individuals with Glut1 DS. A clue to the diagnosis in patients with paroxysmal symptoms may be the triggering of episodes during fasting or exercise. Intellectual impairment may range from severe to very mild. Awareness of the broad range of potential clinical phenotypes associated with Glut1 DS will facilitate earlier diagnosis of this treatable neurologic condition. The ketogenic diet is the mainstay of treatment and nourishes the starving symptomatic brain during development.
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