1
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Mabondzo A, van de Kamp J, Mercimek-Andrews S. Dodecyl creatine ester therapy: from promise to reality. Cell Mol Life Sci 2024; 81:186. [PMID: 38632116 PMCID: PMC11024018 DOI: 10.1007/s00018-024-05218-y] [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: 01/18/2024] [Revised: 02/26/2024] [Accepted: 03/05/2024] [Indexed: 04/19/2024]
Abstract
Pathogenic variants in SLC6A8, the gene which encodes creatine transporter SLC6A8, prevent creatine uptake in the brain and result in a variable degree of intellectual disability, behavioral disorders (e.g., autism spectrum disorder), epilepsy, and severe speech and language delay. There are no treatments to improve neurodevelopmental outcomes for creatine transporter deficiency (CTD). In this spotlight, we summarize recent advances in innovative molecules to treat CTD, with a focus on dodecyl creatine ester, the most promising drug candidate.
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Affiliation(s)
- Aloïse Mabondzo
- Paris Saclay University, CEA, Medicines and Healthcare Technologies Department (MTS), SPI, Neurovascular Unit Research and Therapeutic Innovation Laboratory, 91191, Gif-sur-Yvette cedex, France.
| | - Jiddeke van de Kamp
- Department of Human Genetics, Amsterdam UMC, Vrije Universtiteit Amsterdam, Amsterdam, The Netherlands
| | - Saadet Mercimek-Andrews
- Department of Medical Genetics, Faculty of Medicine and Dentistry, Neurosciences and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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2
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Balestrino M, Adriano E, Alì PA, Pardini M. Selective Alteration of the Left Arcuate Fasciculus in Two Patients Affected by Creatine Transporter Deficiency. Brain Sci 2024; 14:337. [PMID: 38671990 PMCID: PMC11048612 DOI: 10.3390/brainsci14040337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/11/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024] Open
Abstract
(1) Background: In hereditary creatine transporter deficiency (CTD), there is an absence of creatine in the brain and neurological symptoms are present, including severe language impairment. However, the pathological changes caused by creatine deficiency that generate neuropsychological symptoms have been poorly studied. (2) Aims: To investigate if the language impairment in CTD is underpinned by possible pathological changes. (3) Methods: We used MRI tractography to investigate the trophism of the left arcuate fasciculus, a white matter bundle connecting Wernicke's and Broca's language areas that is specifically relevant for language establishment and maintenance, in two patients (28 and 18 y.o.). (4) Results: The T1 and T2 MRI imaging results were unremarkable, but the left arcuate fasciculus showed a marked decrease in mean fractional anisotropy (FA) compared to healthy controls. In contrast, the FA values in the corticospinal tract were similar to those of healthy controls. Although white matter atrophy has been reported in CTD, this is the first report to show a selective abnormality of the language-relevant arcuate fasciculus, suggesting a possible region-specific impact of creatine deficiency.
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Affiliation(s)
- Maurizio Balestrino
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Sciences (DINOGMI), University of Genoa, 16132 Genoa, Italy; (E.A.); (P.A.A.); (M.P.)
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Enrico Adriano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Sciences (DINOGMI), University of Genoa, 16132 Genoa, Italy; (E.A.); (P.A.A.); (M.P.)
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Paolo Alessandro Alì
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Sciences (DINOGMI), University of Genoa, 16132 Genoa, Italy; (E.A.); (P.A.A.); (M.P.)
| | - Matteo Pardini
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Sciences (DINOGMI), University of Genoa, 16132 Genoa, Italy; (E.A.); (P.A.A.); (M.P.)
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
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3
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Sugimoto C, Perna MK, Regan SL, Tepe EA, Liou R, Fritz AL, Williams MT, Vorhees CV, Skelton MR. A Gad2 specific Slc6a8 deletion recapitulates the contextual and cued freezing deficits seen in Slc6a8 -/y mice. Brain Res 2024; 1825:148690. [PMID: 38030104 PMCID: PMC10875619 DOI: 10.1016/j.brainres.2023.148690] [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: 08/21/2023] [Revised: 11/14/2023] [Accepted: 11/25/2023] [Indexed: 12/01/2023]
Abstract
The creatine (Cr)-phosphocreatine shuttle is essential for ATP homeostasis. In humans, the absence of brain Cr causes significant intellectual disability, epilepsy, and language delay. Mutations of the creatine transporter (SLC6A8) are the most common cause of Cr deficiency. In rodents, Slc6a8 deletion causes deficits in spatial learning, novel object recognition (NOR), as well as in contextual and cued freezing. The mechanisms that underlie these cognitive deficits are not known. Due to the heterogeneous nature of the brain, it is important to determine which systems are affected by a loss of Cr. In this study, we generated mice lacking Slc6a8 in GABAergic neurons by crossing Slc6a8FL mice with Gad2-Cre mice. These Gad2-specific Slc6a8 knockout (cKO) mice, along with the ubiquitous Slc6a8 KO (Slc6a8-/y), Gad2-Cre+, and wild-type (WT) mice were tested in the Morris water maze, NOR, conditioned freezing, and the radial water maze. Similar to the Slc6a8-/y mice, cKO mice had reduced contextual and cued freezing compared with WT mice. The cKO mice had a mild spatial learning deficit during the reversal phase of the MWM, however they were not as pronounced as in Slc6a8-/y mice. In NOR, the Gad2-Cre mice spent less time with the novel object, similar to the reduced novel time in the cKO mice. There were no changes in radial water maze performance. Slc6a8 deletion in GABAergic neurons is sufficient to recapitulate the conditioned freezing deficits seen in Slc6a8-/y mice.
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Affiliation(s)
- Chiho Sugimoto
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States
| | - Marla K Perna
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Samantha L Regan
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Erin A Tepe
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States
| | - Rosalyn Liou
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Adam L Fritz
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States
| | - Michael T Williams
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Charles V Vorhees
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Matthew R Skelton
- Department of Pediatrics, University of Cincinnati College of Medicine and Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
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4
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Mejdahl Nielsen M, Petersen ET, Fenger CD, Ørngreen MC, Siebner HR, Boer VO, Považan M, Lund A, Grønborg SW, Hammer TB. X-linked creatine transporter (SLC6A8) deficiency in females: Difficult to recognize, but a potentially treatable disease. Mol Genet Metab 2023; 140:107694. [PMID: 37708665 DOI: 10.1016/j.ymgme.2023.107694] [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: 03/24/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/16/2023]
Abstract
Creatine transporter deficiency (CTD), caused by pathogenic variants in SLC6A8, is the second most common cause of X-linked intellectual disability. Symptoms include intellectual disability, epilepsy, and behavioral disorders and are caused by reduced cerebral creatine levels. Targeted treatment with oral supplementation is available, however the treatment efficacy is still being investigated. There are clinical and theoretical indications that heterozygous females with CTD respond better to supplementation treatment than hemizygous males. Unfortunately, heterozygous females with CTD often have more subtle and uncharacteristic clinical and biochemical phenotypes, rendering diagnosis more difficult. We report a new female case who presented with learning disabilities and seizures. After determining the diagnosis with molecular genetic testing confirmed by proton magnetic resonance spectroscopy (1H-MRS), the patient was treated with supplementation treatment including creatine, arginine, and glycine. After 28 months of treatment, the patient showed prominent clinical improvement and increased creatine levels in the brain. Furthermore, we provide a review of the 32 female cases reported in the current literature including a description of phenotypes, genotypes, diagnostic approaches, and effects of supplementation treatment. Based on this, we find that supplementation treatment should be tested in heterozygous female patients with CTD, and a prospective treatment underlines the importance of diagnosing these patients. The diagnosis should be suspected in a broad clinical spectrum of female patients and can only be made by molecular genetic testing. 1H-MRS of cerebral creatine levels is essential for establishing the diagnosis in females, and especially valuable when assessing variants of unknown significance.
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Affiliation(s)
- Malene Mejdahl Nielsen
- Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
| | - Esben Thade Petersen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark; Section for Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Christina Dühring Fenger
- Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Denmark; Amplexa Genetics, Odense, Denmark
| | - Mette Cathrine Ørngreen
- Center for Inherited Metabolic Diseases, Departments of Pediatrics and Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; European Reference Network for Rare Hereditary Metabolic Disorders (MetabERN) - Project ID No 739543, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Vincent Oltman Boer
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
| | - Michal Považan
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
| | - Allan Lund
- Center for Inherited Metabolic Diseases, Departments of Pediatrics and Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; European Reference Network for Rare Hereditary Metabolic Disorders (MetabERN) - Project ID No 739543, Denmark
| | - Sabine Weller Grønborg
- Center for Inherited Metabolic Diseases, Departments of Pediatrics and Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; European Reference Network for Rare Hereditary Metabolic Disorders (MetabERN) - Project ID No 739543, Denmark
| | - Trine Bjørg Hammer
- Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Denmark
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5
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Li J, Xu S. Diagnosis and Treatment of X-Linked Creatine Transporter Deficiency: Case Report and Literature Review. Brain Sci 2023; 13:1382. [PMID: 37891751 PMCID: PMC10605349 DOI: 10.3390/brainsci13101382] [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: 07/31/2023] [Revised: 09/18/2023] [Accepted: 09/25/2023] [Indexed: 10/29/2023] Open
Abstract
(1) Background: X-linked creatine transporter deficiency (CTD) (OMIM 300036) is a rare group of inherited metabolic disorders characterized by global developmental delay/intellectual disability (GDD/ID), seizures, autistic behavior, and movement disorders. Pathogenic variants in the SLC6A8 gene, located at Xq28, are causative of the disease, leading to impaired creatine transport into the brain. Supplementation with creatine and its precursors, glycine and arginine, has been attempted, yet the treatment efficacy remains controversial. (2) Methods: Here we report a de novo SLC6A8 variant in a boy aged 3 years 9 months presenting with GDD, autistic behavior, and epilepsy. Elevated urinary creatine/creatinine ratio and diminished creatine peak on brain MR spectroscopy suggested the diagnosis of CTD. Genetic sequencing revealed a de novo hemizygous frameshift variant (NM_005629: c.1136_1137del, p. Glu379ValfsTer85). Creatine supplementation therapy was initiated after definitive diagnosis. Electroencephalography and MR spectroscopy were monitored during follow-up in concurrence with neuropsychological evaluations. The clinical phenotype and treatment response of CTD were summarized by systematic view of the literature. (3) Results: In silico analysis showed this variant to be deleterious, probably interfering with substrate binding and conformational changes during creatine transport. Creatine supplementation therapy led to seizure cessation and modest cognitive improvement after half-year's treatment. (4) Conclusions: This case highlights the importance of MR spectroscopy and metabolic screening in males with GDD/ID, allowing for early diagnosis and therapeutic intervention. Mechanistic understanding and case-per-se analysis are required to enable precision treatment for the patients.
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Affiliation(s)
| | - Sanqing Xu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430074, China;
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6
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Ghirardini E, Sagona G, Marquez-Galera A, Calugi F, Navarron CM, Cacciante F, Chen S, Di Vetta F, Dadà L, Mazziotti R, Lupori L, Putignano E, Baldi P, Lopez-Atalaya JP, Pizzorusso T, Baroncelli L. Cell-specific vulnerability to metabolic failure: the crucial role of parvalbumin expressing neurons in creatine transporter deficiency. Acta Neuropathol Commun 2023; 11:34. [PMID: 36882863 PMCID: PMC9990224 DOI: 10.1186/s40478-023-01533-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/14/2023] [Indexed: 03/09/2023] Open
Abstract
Mutations in the solute carrier family 6-member 8 (Slc6a8) gene, encoding the protein responsible for cellular creatine (Cr) uptake, cause Creatine Transporter Deficiency (CTD), an X-linked neurometabolic disorder presenting with intellectual disability, autistic-like features, and epilepsy. The pathological determinants of CTD are still poorly understood, hindering the development of therapies. In this study, we generated an extensive transcriptomic profile of CTD showing that Cr deficiency causes perturbations of gene expression in excitatory neurons, inhibitory cells, and oligodendrocytes which result in remodeling of circuit excitability and synaptic wiring. We also identified specific alterations of parvalbumin-expressing (PV+) interneurons, exhibiting a reduction in cellular and synaptic density, and a hypofunctional electrophysiological phenotype. Mice lacking Slc6a8 only in PV+ interneurons recapitulated numerous CTD features, including cognitive deterioration, impaired cortical processing and hyperexcitability of brain circuits, demonstrating that Cr deficit in PV+ interneurons is sufficient to determine the neurological phenotype of CTD. Moreover, a pharmacological treatment targeted to restore the efficiency of PV+ synapses significantly improved cortical activity in Slc6a8 knock-out animals. Altogether, these data demonstrate that Slc6a8 is critical for the normal function of PV+ interneurons and that impairment of these cells is central in the disease pathogenesis, suggesting a novel therapeutic venue for CTD.
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Affiliation(s)
- Elsa Ghirardini
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Viale del Tirreno 331, 56128, Calambrone (PI), Italy. .,Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy.
| | - Giulia Sagona
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - Angel Marquez-Galera
- Instituto de Neurociencias, Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas, Avenida Santiago Ramon Y Cajal, S/N, 03550, Sant Joan d'Alacant, Alicante, Spain
| | - Francesco Calugi
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, Via Di San Salvi 12, 50135, Florence, Italy.,BIO@SNS Lab, Scuola Normale Superiore Di Pisa, Piazza Dei Cavalieri 7, 56126, Pisa, Italy
| | - Carmen M Navarron
- Instituto de Neurociencias, Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas, Avenida Santiago Ramon Y Cajal, S/N, 03550, Sant Joan d'Alacant, Alicante, Spain
| | - Francesco Cacciante
- BIO@SNS Lab, Scuola Normale Superiore Di Pisa, Piazza Dei Cavalieri 7, 56126, Pisa, Italy
| | - Siwei Chen
- Department of Computer Science and Institute for Genomics and Bioinformatics, University of California, Irvine, CA, 92697-3435, USA
| | - Federica Di Vetta
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - Lorenzo Dadà
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - Raffaele Mazziotti
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy.,Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, Via Di San Salvi 12, 50135, Florence, Italy
| | - Leonardo Lupori
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Viale del Tirreno 331, 56128, Calambrone (PI), Italy
| | - Elena Putignano
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - Pierre Baldi
- Department of Computer Science and Institute for Genomics and Bioinformatics, University of California, Irvine, CA, 92697-3435, USA
| | - Jose P Lopez-Atalaya
- Instituto de Neurociencias, Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas, Avenida Santiago Ramon Y Cajal, S/N, 03550, Sant Joan d'Alacant, Alicante, Spain
| | - Tommaso Pizzorusso
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy.,BIO@SNS Lab, Scuola Normale Superiore Di Pisa, Piazza Dei Cavalieri 7, 56126, Pisa, Italy
| | - Laura Baroncelli
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Viale del Tirreno 331, 56128, Calambrone (PI), Italy.,Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
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7
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Farr CV, El-Kasaby A, Erdem FA, Sucic S, Freissmuth M, Sandtner W. Cooperative Binding of Substrate and Ions Drives Forward Cycling of the Human Creatine Transporter-1. Front Physiol 2022; 13:919439. [PMID: 35837012 PMCID: PMC9273935 DOI: 10.3389/fphys.2022.919439] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/09/2022] [Indexed: 11/25/2022] Open
Abstract
Creatine serves as an ATP buffer and is thus an integral component of cellular energy metabolism. Most cells maintain their creatine levels via uptake by the creatine transporter (CRT-1, SLC6A8). The activity of CRT-1, therefore, is a major determinant of cytosolic creatine concentrations. We determined the kinetics of CRT-1 in real time by relying on electrophysiological recordings of transport-associated currents. Our analysis revealed that CRT-1 harvested the concentration gradient of NaCl and the membrane potential but not the potassium gradient to achieve a very high concentrative power. We investigated the mechanistic basis for the ability of CRT-1 to maintain the forward cycling mode in spite of high intracellular concentrations of creatine: this is achieved by cooperative binding of substrate and co-substrate ions, which, under physiological ion conditions, results in a very pronounced (i.e. about 500-fold) drop in the affinity of creatine to the inward-facing state of CRT-1. Kinetic estimates were integrated into a mathematical model of the transport cycle of CRT-1, which faithfully reproduced all experimental data. We interrogated the kinetic model to examine the most plausible mechanistic basis of cooperativity: based on this systematic exploration, we conclude that destabilization of binary rather than ternary complexes is necessary for CRT-1 to maintain the observed cytosolic creatine concentrations. Our model also provides a plausible explanation why neurons, heart and skeletal muscle cells must express a creatine releasing transporter to achieve rapid equilibration of the intracellular creatine pool.
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Affiliation(s)
| | | | | | | | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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8
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Morey K, Hallinan B, Cecil KM. Case report: Clinical and magnetic resonance spectroscopy presentation of a female severely affected with X-linked creatine transporter deficiency. Radiol Case Rep 2022; 17:1115-1119. [PMID: 35169411 PMCID: PMC8829519 DOI: 10.1016/j.radcr.2022.01.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/30/2022] Open
Abstract
Creatine transporter deficiency is an X-linked genetic disorder caused by a variant in the SLC6A8 gene located on the X chromosome (Xq28). This condition varies in severity with features often including intellectual disabilities, speech delay, autistic features, attention deficit hyperactivity and gastrointestinal issues. While creatine transporter deficiency primarily affects males, females may also demonstrate severe phenotypes. However, screening of creatine transporter deficiency in females can be especially difficult as urine creatine/creatinine screenings often have values falling within normative ranges. Also, females may not demonstrate the characteristic reduction of creatine concentrations in the brain visualized with in vivo proton magnetic resonance spectroscopy. Identification typically results from exome sequencing. In this report, we present the clinical, imaging, and spectroscopy features of a heterozygous female with a severe presentation of creatine transporter deficiency.
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Affiliation(s)
- Katherine Morey
- Summer Undergraduate Research Fellowship Program, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, 3333 Burnet Avenue, MLC 5033, Cincinnati, OH 45229, USA
| | - Barbara Hallinan
- Department of Pediatrics, Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kim M. Cecil
- Department of Radiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, 3333 Burnet Avenue, MLC 5033, Cincinnati, OH 45229, USA
- Corresponding author.
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9
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Fernandes-Pires G, Braissant O. Current and potential new treatment strategies for creatine deficiency syndromes. Mol Genet Metab 2022; 135:15-26. [PMID: 34972654 DOI: 10.1016/j.ymgme.2021.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 12/16/2022]
Abstract
Creatine deficiency syndromes (CDS) are inherited metabolic disorders caused by mutations in GATM, GAMT and SLC6A8 and mainly affect central nervous system (CNS). AGAT- and GAMT-deficient patients lack the functional brain endogenous creatine (Cr) synthesis pathway but express the Cr transporter SLC6A8 at blood-brain barrier (BBB), and can thus be treated by oral supplementation of high doses of Cr. For Cr transporter deficiency (SLC6A8 deficiency or CTD), current treatment strategies benefit one-third of patients. However, as their phenotype is not completely reversed, and for the other two-thirds of CTD patients, the development of novel more effective therapies is needed. This article aims to review the current knowledge on Cr metabolism and CDS clinical aspects, highlighting their current treatment possibilities and the most recent research perspectives on CDS potential therapeutics designed, in particular, to bring new options for the treatment of CTD.
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Affiliation(s)
- Gabriella Fernandes-Pires
- Service of Clinical Chemistry, University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland
| | - Olivier Braissant
- Service of Clinical Chemistry, University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland.
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10
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Baker SA, Gajera CR, Wawro AM, Corces MR, Montine TJ. GATM and GAMT synthesize creatine locally throughout the mammalian body and within oligodendrocytes of the brain. Brain Res 2021; 1770:147627. [PMID: 34418357 DOI: 10.1016/j.brainres.2021.147627] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 08/08/2021] [Accepted: 08/14/2021] [Indexed: 11/17/2022]
Abstract
The enzymes glycine amidinotransferase, mitochondrial (GATM also known as AGAT) and guanidinoacetate N-methyltransferase (GAMT) function together to synthesize creatine from arginine, glycine, and S-Adenosyl methionine. Deficiency in either enzyme or the creatine transporter, CT1, results in a devastating neurological disorder, Cerebral Creatine Deficiency Syndrome (CCDS). To better understand the pathophysiology of CCDS, we mapped the distribution of GATM and GAMT at single cell resolution, leveraging RNA sequencing analysis combined with in vivo immunofluorescence (IF). Using the mouse as a model system, we find that GATM and GAMT are coexpressed in several tissues with distinct and overlapping cellular sources, implicating local synthesis as an important mechanism of creatine metabolism in numerous organs. Extending previous findings at the RNA level, our analysis demonstrates that oligodendrocytes express the highest level of Gatm and Gamt of any cell type in the body. We confirm this finding in the mouse brain by IF, where GATM localizes to the mitochondria of oligodendrocytes, whereas both oligodendrocytes and cerebral cortical neurons express GAMT. Interestingly, the latter is devoid of GATM. Single nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq) analysis of 4 brain regions highlights a similar primacy of oligodendrocytes in the expression of GATM and GAMT in the human central nervous system. Importantly, an active putative regulatory element within intron 2 of human GATM is detected in oligodendrocytes but not neurons.
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Affiliation(s)
- Steven Andrew Baker
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Chandresh R Gajera
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Adam M Wawro
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - M Ryan Corces
- Gladstone Institute of Neurological Disease, Gladstone Institute of Data Science and Biotechnology, San Francisco, CA 94158, USA; Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Thomas J Montine
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94035, USA; Lead Contact.
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11
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Wawro AM, Gajera CR, Baker SA, Nirschl JJ, Vogel H, Montine TJ. Creatine transport and pathological changes in creatine transporter deficient mice. J Inherit Metab Dis 2021; 44:939-948. [PMID: 33389772 DOI: 10.1002/jimd.12358] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 01/26/2023]
Abstract
The severe impact on brain function and lack of effective therapy for patients with creatine (Cr) transporter deficiency motivated the generation of three ubiquitous Slc6a8 deficient mice (-/y). While each mouse knock-out line has similar behavioral effects at 2 to 3 months of age, other features critical to the efficient use of these mice in drug discovery are unclear or lacking: the concentration of Cr in brain and heart differ widely between mouse lines, there are limited data on histopathologic changes, and no data on Cr uptake. Here, we determined survival, measured endogenous Cr and uptake of its deuterium-labeled analogue Cr-d3 using a liquid chromatography coupled with tandem mass spectrometry assay, and performed comprehensive histopathologic examination on the Slc6a8-/y mouse developed by Skelton et al. Our results show that Slc6a8-/y mice have widely varying organ-specific uptake of Cr-d3, significantly diminished growth with the exception of brain, progressive vacuolar myopathy, and markedly shortened lifespan.
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Affiliation(s)
- Adam M Wawro
- Department of Pathology, Stanford University, Stanford, California, USA
| | | | - Steven A Baker
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Jeffrey J Nirschl
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Hannes Vogel
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Thomas J Montine
- Department of Pathology, Stanford University, Stanford, California, USA
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Shi K, Zhao H, Xu S, Han H, Li W. Treatment efficacy of high-dose creatine supplementation in a child with creatine transporter (SLC6A8) deficiency. Mol Genet Genomic Med 2021; 9:e1640. [PMID: 33656256 PMCID: PMC8123749 DOI: 10.1002/mgg3.1640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/10/2021] [Indexed: 01/03/2023] Open
Abstract
Background Creatine transporter deficiency is an inborn error of metabolism caused by a deficiency in the creatine transporter protein encoded by the SLC6A8 gene. Previous treatment with creatine supplementation, either alone or in combination with creatine precursors (arginine or glycine), has been attempted; the efficacy of therapy, however, remains controversial. Methods and Results To analyze the treatment efficacy of high‐dose creatine supplementation on creatine transporter deficiency, we reported a child diagnosed with creatine transporter deficiency, who was treated with a conventional dose of creatine (400 mg/kg/d) for 1 month, then twice the dose (800 mg/kg/d) for 2 months, and finally 3 times the dose (1200 mg/kg/d) for 3 months. The patient tolerated the treatment well and showed improvements in muscle mass and strength when the creatine dose was gradually increased to 1200 mg/kg/d. However, when assessed by proton magnetic resonance spectroscopy (H‐MRS), the brain creatine concentration did not increase, and there was no improvement in speech and neurodevelopmental symptoms. Conclusion We conclude that high‐dose creatine supplementation (1200 mg/kg/d) alone improved muscular symptoms, but did not improve cognitive symptoms and brain creatine concentration assessed using H‐MRS. Therefore, new treatment strategies are required for the management of creatine transporter deficiency. Creatine transporter deficiency is an inborn error of metabolism caused by a deficiency in the creatine transporter protein encoded by the SLC6A8 gene. Previously treatment with creatine supplementation, either alone or in combination with creatine precursors (arginine or glycine), has been attempted; the efficacy of therapy, however, remains controversial. We conclude that high‐dose creatine supplementation (1200 mg/kg/d) alone improved muscular symptoms, but did not improve cognitive symptoms and brain creatine concentration assessed using proton magnetic resonance spectroscopy. Therefore, new treatment strategies are required for the management of creatine transporter deficiency.
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Affiliation(s)
- Kaili Shi
- Department of Neurology, Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Huimin Zhao
- Department of pediatrics, Shan'xi Medical University, Taiyuan, China
| | - Shuming Xu
- Department of Imaging of Shanxi, Children's Hospital, Taiyuan, China
| | - Hong Han
- Department of Neurology of Shanxi, Children's Hospital, Taiyuan, China
| | - Wenjuan Li
- Department of Neurology, Guangzhou Women and Children's Medical Center, Guangzhou, China
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Abstract
Pediatric epilepsy is a highly variable condition due to age-related expression of syndromes that require specific diagnosis, evaluations, and treatments. Children with epilepsy differ from their adult counterparts in many important ways, mostly related to the age-related expression of specific epilepsy syndromes. This results in many important considerations related to the epilepsy diagnosis, classification, evaluations to determine an etiology, as well as treatment guidelines. A good understanding of these factors will help to establish an accurate epilepsy diagnosis, which in turn will guide appropriate testing and treatment decisions. In this way, patients will have improved seizure outcomes, and families will be educated appropriately and provided with the most accurate prognostic information available. The purpose of this article is to review the diagnosis, work-up, and management of pediatric epilepsy.
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Affiliation(s)
- Jeffrey R Tenney
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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14
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Sinha A, Ahmed S, George C, Tsagaris M, Naufer A, von Both I, Tkachyova I, van Eede M, Henkelman M, Schulze A. Magnetic resonance imaging reveals specific anatomical changes in the brain of Agat- and Gamt-mice attributed to creatine depletion and guanidinoacetate alteration. J Inherit Metab Dis 2020; 43:827-842. [PMID: 31951021 DOI: 10.1002/jimd.12215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/30/2019] [Accepted: 01/09/2020] [Indexed: 11/07/2022]
Abstract
Arginine:glycine amidinotransferase- and guanidinoacetate methyltransferase deficiency are severe neurodevelopmental disorders. It is not known whether mouse models of disease express a neuroanatomical phenotype. High-resolution magnetic resonance imaging (MRI) with advanced image analysis was performed in perfused, fixed mouse brains encapsulated with the skull from male, 10-12 week old Agat -exc and B6J.Cg-Gamt tm1Isb mice (n = 48; n = 8 per genotype, strain). T2-weighted MRI scans were nonlinearly aligned to a 3D atlas of the mouse brain with 62 structures identified. Local differences in brain shape related to genotype were assessed by analysis of deformation fields. Creatine (Cr) and guanidinoacetate (GAA) were measured with high-performance liquid chromatography (HPLC) in brain homogenates (n = 24; n = 4 per genotype, strain) after whole-body perfusion. Cr was decreased in the brain of Agat- and Gamt mutant mice. GAA was decreased in Agat-/- and increased in Gamt-/- . Body weight and brain volume were lower in Agat-/- than in Gamt-/- . The analysis of entire brain structures revealed corpus callosum, internal capsule, fimbria and hypothalamus being different between the genotypes in both strains. Eighteen and fourteen significant peaks (local areas of difference in relative size) were found in Agat- and Gamt mutants, respectively. Comparing Agat-/- with Gamt-/- , we found changes in three brain regions, lateral septum, amygdala, and medulla. Intra-strain differences in four brain structures can be associated with Cr deficiency, while the inter-strain differences in three brain structures of the mutant mice may relate to GAA. Correlating these neuroanatomical findings with gene expression data implies the role of Cr metabolism in the developing brain and the importance of early intervention in patients with Cr deficiency syndromes.
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Affiliation(s)
- Ankit Sinha
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sohail Ahmed
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Chris George
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melina Tsagaris
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Amriya Naufer
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ingo von Both
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ilona Tkachyova
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Matthijs van Eede
- Mouse Imaging Centre, Toronto Center of Phenogenomics, Toronto, Ontario, Canada
| | - Mark Henkelman
- Mouse Imaging Centre, Toronto Center of Phenogenomics, Toronto, Ontario, Canada
- Neurosciences and Mental Health Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andreas Schulze
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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15
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Dinesh OC, Brunton JA, Bertolo RF. The Kidneys Are Quantitatively More Important than Pancreas and Gut as a Source of Guanidinoacetic Acid for Hepatic Creatine Synthesis in Sow-Reared Yucatan Miniature Piglets. J Nutr 2020; 150:443-449. [PMID: 31687740 DOI: 10.1093/jn/nxz266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/20/2019] [Accepted: 10/04/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Arginine:glycine amidinotransferase, necessary for the conversion of arginine (Arg) to guanidinoacetic acid (GAA), is expressed mainly in kidney and pancreas. The methylation of GAA to creatine (Cre) primarily occurs in the liver. The role of the gut in Cre homeostasis has not been characterized. OBJECTIVE We aimed to quantify the contribution of kidney, pancreas, and gut as sources of GAA for Cre synthesis. METHODS Sow-reared, feed-deprived Yucatan miniature piglets (17-21 d old) were randomly assigned to acute intravenous treatments (expressed in μmol/kg/min) of: 1) Arg (4.8) + methionine (1.4) (Arg/Met), 2) Cre (0.6) with Arg/Met (Cre/Arg/Met), 3) citrulline (4.8) + methionine (1.4) (Cit/Met), or 4) alanine (6.2) (Ala). Suckling piglets were also studied. RESULTS Renal GAA release was higher during Cit/Met compared with all other treatments (53-360% higher; P < 0.01), suggesting that Cit is a better precursor than Arg for renal GAA synthesis. Kidneys contributed higher (P < 0.01) proportions of the total GAA with Cit/Met (89%) and Arg/Met (68%) treatments compared with pancreas and gut. In the suckling pigs, kidneys contributed 88% of the GAA, with the remainder released by pancreas. None of the treatments resulted in a net flux of Cre across the kidney or pancreas. In the gut, Arg/Met and Cre/Arg/Met, but not Cit/Met, resulted in a net release of Cre. Cre/Arg/Met resulted in a higher net GAA release from the gut (P < 0.0001) and pancreas (P < 0.001) (68% of total GAA produced) compared with all other treatments (<19% from both organs), perhaps because GAA not needed for creatine synthesis was subsequently released. CONCLUSIONS Cit is a better precursor than Arg for renal GAA synthesis, and kidney is the major source of GAA for Cre synthesis in neonatal piglets, but the gut also has the capacity to synthesize GAA and Cre when Arg and Met are available.
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Affiliation(s)
- O Chandani Dinesh
- Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland, Canada
| | - Janet A Brunton
- Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland, Canada
| | - Robert F Bertolo
- Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland, Canada
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Deletion of the Creatine Transporter (Slc6a8) in Dopaminergic Neurons Leads to Hyperactivity in Mice. J Mol Neurosci 2019; 70:102-111. [PMID: 31520365 DOI: 10.1007/s12031-019-01405-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/30/2019] [Indexed: 12/27/2022]
Abstract
The lack of cerebral creatine (Cr) causes intellectual disability and epilepsy. In addition, a significant portion of individuals with Cr transporter (Crt) deficiency (CTD), the leading cause of cerebral Cr deficiency syndromes (CCDS), are diagnosed with attention-deficit hyperactivity disorder. While the neurological effects of CTD are clear, the mechanisms that underlie these deficits are unknown. Part of this is due to the heterogenous nature of the brain and the unique metabolic demands of specific neuronal systems. Of particular interest related to Cr physiology are dopaminergic neurons, as many CCDS patients have ADHD and Cr has been implicated in dopamine-associated neurodegenerative disorders, such as Parkinson's and Huntington's diseases. The purpose of this study was to examine the effect of a loss of the Slc6a8 (Crt) gene in dopamine transporter (Slc6a3; DAT) expressing cells on locomotor activity and motor function as the mice age. Floxed Slc6a8 (Slc6a8flox) mice were mated to DATIREScre expressing mice to generate DAT-specific Slc6a8 knockouts (dCrt-/y). Locomotor activity, spontaneous activity, and performance in the challenging beam test were evaluated monthly in dCrt-/y and control (Slc6a8flox) mice from 3 to 12 months of age. dCrt-/y mice were hyperactive compared with controls throughout testing. In addition, dCrt-/y mice showed increased rearing and hindlimb steps in the spontaneous activity test. Latency to cross the narrow bridge was increased in dCrt-/y mice while foot slips were unchanged. Taken together, these data suggest that the lack of Cr in dopaminergic neurons causes hyperactivity while sparing motor function.
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17
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Wang Q, Yang J, Liu Y, Li X, Luo F, Xie J. A novel SLC6A8 mutation associated with intellectual disabilities in a Chinese family exhibiting creatine transporter deficiency: case report. BMC MEDICAL GENETICS 2018; 19:193. [PMID: 30400883 PMCID: PMC6219255 DOI: 10.1186/s12881-018-0707-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/22/2018] [Indexed: 12/19/2022]
Abstract
Background X-linked creatine transporter deficiency (OMIM#300036,CRTR-D) is characterized by cerebral creatine deficiency, intellectual disabilities, severe speech impairment, seizures and behavioral problems. Mutations in the creatine transporter gene SLC6A8, a member of the solute-carrier family 6 mapped to Xq28, have been reported to cause the creatine transporter deficiency. Case presentation The proband presented at 5 yrs. 1 month of age with delays in intellectual and development, seizures and behavioral problems. A novel missense mutation, c.1181C > A (p.Thr394Lys), in the SLC6A8 gene (NM_005629.3) was detected via targeted exome sequencing, and then validated by Sanger sequencing. Multiple in silico variant effect analysis methods, including SIFT, PolyPhen2, PROVEAN, and Mutation Taster predicted that this variant was likely damaging or diseasing-causing. This hemizygous variation was also identified in the affected brother with the same clinical condition and inherited from the heterozygous carrier mother. The diagnosis was suggested by increased urinary creatine/creatinine (Cr:Crn) ratio and markedly reduced creatine content peak by brain proton magnetic resonance spectroscopy (MRS). The proband’s mother became pregnant with a 3rd sibling, in whom the Sanger sequencing result of c.1181C > A was negative. Conclusion The novel mutation c.1181C > A in the SLC6A8 gene reported in a Chinese family has expanded the mutation spectrum of CRTR-D. The combination of powerful new technologies such as targeted exome sequencing with thorough systematic clinical evaluation of patients will improve the diagnostic yield, and assist in genetic counselling and prenatal diagnosis for suspected genetic disorders. Electronic supplementary material The online version of this article (10.1186/s12881-018-0707-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qin Wang
- Shenzhen Maternity and Child Healthcare Hospital, No. 3012, Fuqiang Road, Shenzhen, 518028, Guangdong, China
| | - Jingxin Yang
- Shenzhen Maternity and Child Healthcare Hospital, No. 3012, Fuqiang Road, Shenzhen, 518028, Guangdong, China
| | - Yang Liu
- Shenzhen Maternity and Child Healthcare Hospital, No. 3012, Fuqiang Road, Shenzhen, 518028, Guangdong, China
| | - Xingping Li
- Shenzhen Maternity and Child Healthcare Hospital, No. 3012, Fuqiang Road, Shenzhen, 518028, Guangdong, China
| | - Fuwei Luo
- Shenzhen Maternity and Child Healthcare Hospital, No. 3012, Fuqiang Road, Shenzhen, 518028, Guangdong, China
| | - Jiansheng Xie
- Shenzhen Maternity and Child Healthcare Hospital, No. 3012, Fuqiang Road, Shenzhen, 518028, Guangdong, China.
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18
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Dinesh OC, Bertolo RF, Brunton JA. Creatine supplementation to total parenteral nutrition improves creatine status and supports greater liver and kidney protein synthesis in neonatal piglets. Pediatr Res 2018; 83:135-141. [PMID: 28846669 DOI: 10.1038/pr.2017.208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/21/2017] [Indexed: 11/09/2022]
Abstract
BackgroundCreatine is not included in commercial pediatric parenteral products; the entire creatine requirement must be met by de novo synthesis from arginine during parenteral nutrition (PN). Poor arginine status is common during PN in neonates, which may compromise creatine accretion. We hypothesized that creatine supplementation will improve creatine status and spare arginine in PN-fed piglets.MethodsPiglets (3-5-day (d) old) were provided PN with or without creatine for 14 d. Tissue concentrations of creatine metabolites and activities of creatine-synthesizing enzymes, as well as tissue protein synthesis rates and liver lipid parameters, were measured.ResultsCreatine provision lowered kidney and pancreas L-arginine:glycine amidinotransferase (AGAT, EC number 2.1.4.1) activities and plasma guanidinoacetic acid (GAA) concentration, suggesting the downregulation of de novo creatine synthesis. Creatine increased plasma creatine concentrations to sow-fed reference levels and increased the creatine concentrations in most tissues, but not in the brain. PN creatine resulted in greater protein synthesis in the liver and the kidney, but not in the pancreas, skeletal muscle, or gut. Creatine supplementation also reduced liver cholesterol concentrations, but not triglyceride or total fat.ConclusionThe addition of creatine to PN may optimize the accretion of creatine and reduce the metabolic burden of creatine synthesis in rapidly growing neonates.
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Affiliation(s)
- O Chandani Dinesh
- Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada
| | - Robert F Bertolo
- Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada
| | - Janet A Brunton
- Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada
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Neuroimaging of Pediatric Metabolic Disorders with Emphasis on Diffusion-Weighted Imaging and MR Spectroscopy: A Pictorial Essay. CURRENT RADIOLOGY REPORTS 2017. [DOI: 10.1007/s40134-017-0251-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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20
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Uemura T, Ito S, Ohta Y, Tachikawa M, Wada T, Terasaki T, Ohtsuki S. Abnormal N-Glycosylation of a Novel Missense Creatine Transporter Mutant, G561R, Associated with Cerebral Creatine Deficiency Syndromes Alters Transporter Activity and Localization. Biol Pharm Bull 2017; 40:49-55. [PMID: 28049948 DOI: 10.1248/bpb.b16-00582] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebral creatine deficiency syndromes (CCDSs) are caused by loss-of-function mutations in creatine transporter (CRT, SLC6A8), which transports creatine at the blood-brain barrier and into neurons of the central nervous system (CNS). This results in low cerebral creatine levels, and patients exhibit mental retardation, poor language skills and epilepsy. We identified a novel human CRT gene missense mutation (c.1681 G>C, G561R) in Japanese CCDSs patients. The purpose of the present study was to evaluate the reduction of creatine transport in G561R-mutant CRT-expressing 293 cells, and to clarify the mechanism of its functional attenuation. G561R-mutant CRT exhibited greatly reduced creatine transport activity compared to wild-type CRT (WT-CRT) when expressed in 293 cells. Also, the mutant protein is localized mainly in intracellular membrane fraction, while WT-CRT is localized in plasma membrane. Western blot analysis revealed a 68 kDa band of WT-CRT protein in plasma membrane fraction, while G561R-mutant CRT protein predominantly showed bands at 55, 110 and 165 kDa in crude membrane fraction. The bands of both WT-CRT and G561R-mutant CRT were shifted to 50 kDa by N-glycosidase treatment. Our results suggest that the functional impairment of G561R-mutant CRT was probably caused by incomplete N-linked glycosylation due to misfolding during protein maturation, leading to oligomer formation and changes of cellular localization.
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Affiliation(s)
- Tatsuki Uemura
- Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University
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21
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Heussinger N, Saake M, Mennecke A, Dörr HG, Trollmann R. Variable White Matter Atrophy and Intellectual Development in a Family With X-linked Creatine Transporter Deficiency Despite Genotypic Homogeneity. Pediatr Neurol 2017; 67:45-52. [PMID: 28065824 DOI: 10.1016/j.pediatrneurol.2016.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/02/2016] [Accepted: 10/08/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND The X-linked creatine transporter deficiency (CRTD) caused by an SLC6A8 mutation represents the second most common cause of X-linked intellectual disability. The clinical phenotype ranges from mild to severe intellectual disability, epilepsy, short stature, poor language skills, and autism spectrum disorders. The objective of this study was to investigate phenotypic variability in the context of genotype, cerebral creatine concentration, and volumetric analysis in a family with CRTD. PATIENTS AND METHODS The clinical phenotype and manifestations of epilepsy were assessed in a Caucasian family with CRTD. DNA sequencing and creatine metabolism analysis confirmed the diagnosis. Cerebral magnetic resonance imaging (cMRI) with voxel-based morphometry and magnetic resonance spectroscopy was performed in all family members. RESULTS An SLC6A8 missense mutation (c.1169C>T; p.Pro390Leu, exon 8) was detected in four of five individuals. Both male siblings were hemizygous, the mother and the affected sister heterozygous for the mutation. Structural cMRI was normal, whereas voxel-based morphometry analysis showed reduced white matter volume below the first percentile of the reference population of 290 subjects in the more severely affected boy compared with family members and controls. Normalized creatine concentration differed significantly between the individuals (P < 0.005). CONCLUSIONS There is a broad phenotypic variability in CRTD even in family members with the same mutation. Differences in mental development could be related to atrophy of the subcortical white matter.
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Affiliation(s)
- Nicole Heussinger
- Department of Pediatrics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany.
| | - Marc Saake
- Department of Radiology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Angelika Mennecke
- Department of Neuroradiology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Helmuth-Günther Dörr
- Department of Pediatrics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Regina Trollmann
- Department of Pediatrics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
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Rackayova V, Cudalbu C, Pouwels PJW, Braissant O. Creatine in the central nervous system: From magnetic resonance spectroscopy to creatine deficiencies. Anal Biochem 2016; 529:144-157. [PMID: 27840053 DOI: 10.1016/j.ab.2016.11.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 10/20/2022]
Abstract
Creatine (Cr) is an important organic compound acting as intracellular high-energy phosphate shuttle and in energy storage. While located in most cells where it plays its main roles in energy metabolism and cytoprotection, Cr is highly concentrated in muscle and brain tissues, in which Cr also appears to act in osmoregulation and neurotransmission. This review discusses the basis of Cr metabolism, synthesis and transport within brain cells. The importance of Cr in brain function and the consequences of its impaired metabolism in primary and secondary Cr deficiencies are also discussed. Cr and phosphocreatine (PCr) in living systems can be well characterized using in vivo magnetic resonance spectroscopy (MRS). This review describes how 1H MRS allows the measurement of Cr and PCr, and how 31P MRS makes it possible to estimate the creatine kinase (CK) rate constant and so detect dynamic changes in the Cr/PCr/CK system. Absolute quantification by MRS using creatine as internal reference is also debated. The use of in vivo MRS to study brain Cr in a non-invasive way is presented, as well as its use in clinical and preclinical studies, including diagnosis and treatment follow-up in patients.
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Affiliation(s)
- Veronika Rackayova
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Petra J W Pouwels
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands
| | - Olivier Braissant
- Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, Lausanne, Switzerland.
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Creatine transporter deficiency leads to increased whole body and cellular metabolism. Amino Acids 2016; 48:2057-65. [PMID: 27401086 DOI: 10.1007/s00726-016-2291-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 06/29/2016] [Indexed: 12/31/2022]
Abstract
Creatine (Cr) is a guanidino compound required for rapid replenishment of ATP in cells with a high-energy demand. In humans, mutations in the Cr transporter (CRT;SLC6A8) prevent Cr entry into tissue and result in a significant intellectual impairment, epilepsy, and aphasia. The lack of Cr on both the whole body and cellular metabolism was evaluated in Crt knockout (Crt (-/y) ) mice, a high-fidelity model of human CRT deficiency. Crt (-/y) mice have reduced body mass and, however, show a twofold increase in body fat. There was increased energy expenditure in a home cage environment and during treadmill running in Crt (-/y) mice. Consistent with the increases in the whole-body metabolic function, Crt (-/y) mice show increased cellular metabolism as well. Mitochondrial respiration increased in skeletal muscle fibers and hippocampal lysates from Crt (-/y) mice. In addition, Crt (-/y) mice had increased citrate synthase activity, suggesting a higher number of mitochondria instead of an increase in mitochondrial activity. To determine if the increase in respiration was due to increased mitochondrial numbers, we measured oxygen consumption in an equal number of mitochondria from Crt (+/y) and Crt (-/y) mice. There were no changes in mitochondrial respiration when normalized to mitochondrial number, suggesting that the increase in respiration observed could be to higher mitochondrial content in Crt (-/y) mice.
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Ardon O, Procter M, Mao R, Longo N, Landau Y, Shilon-Hadass A, Gabis L, Hoffmann C, Tzadok M, Heimer G, Sada S, Ben-Zeev B, Anikster Y. Creatine transporter deficiency: Novel mutations and functional studies. Mol Genet Metab Rep 2016; 8:20-3. [PMID: 27408820 PMCID: PMC4932609 DOI: 10.1016/j.ymgmr.2016.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 06/24/2016] [Accepted: 06/24/2016] [Indexed: 12/31/2022] Open
Abstract
X-linked cerebral creatine deficiency (MIM 300036) is caused by deficiency of the creatine transporter encoded by the SLC6A8 gene. Here we report three patients with this condition from Israel. These unrelated patients were evaluated for global developmental delays and language apraxia. Borderline microcephaly was noted in one of them. Diagnosis was prompted by brain magnetic resonance imaging and spectroscopy which revealed normal white matter distribution, but absence of the creatine peak in all three patients. Biochemical testing indicated normal plasma levels of creatine and guanidinoacetate, but an increased urine creatine/creatinine ratio. The diagnosis was confirmed by demonstrating absent ([14])C-creatine transport in fibroblasts. Molecular studies indicated that the first patient is hemizygous for a single nucleotide change substituting a single amino acid (c.619 C > T, p.R207W). Expression studies in HeLa cells confirmed the causative role of the R207W substitution. The second patient had a three base pair deletion in the SLC6A8 gene (c.1222_1224delTTC, p.F408del) as well as a single base change (c.1254 + 1G > A) at a splicing site in the intron-exon junction of exon 8, the latter occurring de novo. The third patient, had a three base pair deletion (c.1006_1008delAAC, p.N336del) previously reported in other patients with creatine transporter deficiency. These three patients are the first reported cases of creatine transporter deficiency in Israel.
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Affiliation(s)
- O. Ardon
- Research and Development, ARUP Laboratories, Salt Lake City, UT, USA
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - M. Procter
- Research and Development, ARUP Laboratories, Salt Lake City, UT, USA
| | - R. Mao
- Research and Development, ARUP Laboratories, Salt Lake City, UT, USA
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - N. Longo
- Research and Development, ARUP Laboratories, Salt Lake City, UT, USA
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
- Corresponding author at: Division of Medical Genetics, Department of Pediatrics, University of Utah, 295 Chipeta Way, Salt Lake City, UT 84108, USA.Division of Medical GeneticsDepartment of PediatricsUniversity of Utah295 Chipeta WaySalt Lake CityUT84108USA
| | - Y.E. Landau
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - A. Shilon-Hadass
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - L.V. Gabis
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - C. Hoffmann
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - M. Tzadok
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - G. Heimer
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
- Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital and The Dr. Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Tel-Hashomer, Israel
| | - S. Sada
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - B. Ben-Zeev
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
| | - Y. Anikster
- Edmond and Lily Safra Children's hospital and Sackler Faculty of Medicine, TAU, Sheba Medical Center, Israel
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Hanna-El-Daher L, Braissant O. Creatine synthesis and exchanges between brain cells: What can be learned from human creatine deficiencies and various experimental models? Amino Acids 2016; 48:1877-95. [PMID: 26861125 DOI: 10.1007/s00726-016-2189-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/27/2016] [Indexed: 12/11/2022]
Abstract
While it has long been thought that most of cerebral creatine is of peripheral origin, the last 20 years has provided evidence that the creatine synthetic pathway (AGAT and GAMT enzymes) is expressed in the brain together with the creatine transporter (SLC6A8). It has also been shown that SLC6A8 is expressed by microcapillary endothelial cells at the blood-brain barrier, but is absent from surrounding astrocytes, raising the concept that the blood-brain barrier has a limited permeability for peripheral creatine. The first creatine deficiency syndrome in humans was also discovered 20 years ago (GAMT deficiency), followed later by AGAT and SLC6A8 deficiencies, all three diseases being characterized by creatine deficiency in the CNS and essentially affecting the brain. By reviewing the numerous and latest experimental studies addressing creatine transport and synthesis in the CNS, as well as the clinical and biochemical characteristics of creatine-deficient patients, our aim was to delineate a clearer view of the roles of the blood-brain and blood-cerebrospinal fluid barriers in the transport of creatine and guanidinoacetate between periphery and CNS, and on the intracerebral synthesis and transport of creatine. This review also addresses the question of guanidinoacetate toxicity for brain cells, as probably found under GAMT deficiency.
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MESH Headings
- Amidinotransferases/deficiency
- Amidinotransferases/genetics
- Amidinotransferases/metabolism
- Amino Acid Metabolism, Inborn Errors/genetics
- Amino Acid Metabolism, Inborn Errors/metabolism
- Amino Acid Metabolism, Inborn Errors/pathology
- Animals
- Blood-Brain Barrier/metabolism
- Blood-Brain Barrier/pathology
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/metabolism
- Brain Diseases, Metabolic, Inborn/pathology
- Capillaries/metabolism
- Capillaries/pathology
- Creatine/biosynthesis
- Creatine/deficiency
- Creatine/genetics
- Creatine/metabolism
- Developmental Disabilities/genetics
- Developmental Disabilities/metabolism
- Developmental Disabilities/pathology
- Disease Models, Animal
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Guanidinoacetate N-Methyltransferase/deficiency
- Guanidinoacetate N-Methyltransferase/genetics
- Guanidinoacetate N-Methyltransferase/metabolism
- Humans
- Intellectual Disability/genetics
- Intellectual Disability/metabolism
- Intellectual Disability/pathology
- Language Development Disorders/genetics
- Language Development Disorders/metabolism
- Language Development Disorders/pathology
- Mental Retardation, X-Linked/genetics
- Mental Retardation, X-Linked/metabolism
- Mental Retardation, X-Linked/pathology
- Movement Disorders/congenital
- Movement Disorders/genetics
- Movement Disorders/metabolism
- Movement Disorders/pathology
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Plasma Membrane Neurotransmitter Transport Proteins/deficiency
- Plasma Membrane Neurotransmitter Transport Proteins/genetics
- Plasma Membrane Neurotransmitter Transport Proteins/metabolism
- Speech Disorders/genetics
- Speech Disorders/metabolism
- Speech Disorders/pathology
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Affiliation(s)
- Layane Hanna-El-Daher
- Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, 1011, Lausanne, Switzerland
| | - Olivier Braissant
- Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, 1011, Lausanne, Switzerland.
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26
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Clark JF, Cecil KM. Diagnostic methods and recommendations for the cerebral creatine deficiency syndromes. Pediatr Res 2015; 77:398-405. [PMID: 25521922 DOI: 10.1038/pr.2014.203] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/15/2014] [Indexed: 12/29/2022]
Abstract
Primary care pediatricians and a variety of specialist physicians strive to define an accurate diagnosis for children presenting with impairment of expressive speech and delay in achieving developmental milestones. Within the past two decades, a group of disorders featuring this presentation have been identified as cerebral creatine deficiency syndromes (CCDS). Patients with these disorders were initially discerned using proton magnetic resonance spectroscopy of the brain within a magnetic resonance imaging (MRI) examination. The objective of this review is to provide the clinician with an overview of the current information available on identifying and treating these conditions. We explain the salient features of creatine metabolism, synthesis, and transport required for normal development. We propose diagnostic approaches for confirming a CCDS diagnosis. Finally, we describe treatment approaches for managing patients with these conditions.
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Affiliation(s)
- Joseph F Clark
- Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Kim M Cecil
- 1] Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio [2] Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio [3] Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio [4] Department of Radiology and Medical Imaging, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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27
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Baroncelli L, Alessandrì MG, Tola J, Putignano E, Migliore M, Amendola E, Gross C, Leuzzi V, Cioni G, Pizzorusso T. A novel mouse model of creatine transporter deficiency. F1000Res 2014; 3:228. [PMID: 25485098 PMCID: PMC4243761 DOI: 10.12688/f1000research.5369.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/25/2014] [Indexed: 12/29/2022] Open
Abstract
Mutations in the creatine (Cr) transporter (CrT) gene lead to cerebral creatine deficiency syndrome-1 (CCDS1), an X-linked metabolic disorder characterized by cerebral Cr deficiency causing intellectual disability, seizures, movement and behavioral disturbances, language and speech impairment ( OMIM #300352). CCDS1 is still an untreatable pathology that can be very invalidating for patients and caregivers. Only two murine models of CCDS1, one of which is an ubiquitous knockout mouse, are currently available to study the possible mechanisms underlying the pathologic phenotype of CCDS1 and to develop therapeutic strategies. Given the importance of validating phenotypes and efficacy of promising treatments in more than one mouse model we have generated a new murine model of CCDS1 obtained by ubiquitous deletion of 5-7 exons in the
Slc6a8 gene. We showed a remarkable Cr depletion in the murine brain tissues and cognitive defects, thus resembling the key features of human CCDS1. These results confirm that CCDS1 can be well modeled in mice. This CrT
−/y murine model will provide a new tool for increasing the relevance of preclinical studies to the human disease.
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Affiliation(s)
- Laura Baroncelli
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Maria Grazia Alessandrì
- Department of Developmental Neuroscience, IRCCS Stella Maris Scientific Institute, Calambrone (Pisa), I-56128, Italy
| | - Jonida Tola
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Elena Putignano
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Martina Migliore
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Elena Amendola
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), Monterotondo (Roma), I-00015, Italy
| | - Cornelius Gross
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), Monterotondo (Roma), I-00015, Italy
| | - Vincenzo Leuzzi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome, Rome, I-00185, Italy
| | - Giovanni Cioni
- Department of Developmental Neuroscience, IRCCS Stella Maris Scientific Institute, Calambrone (Pisa), I-56128, Italy ; Department of Clinical and Experimental Medicine, University of Pisa, Pisa, I-56126, Italy
| | - Tommaso Pizzorusso
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy ; Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, Florence, I-50135, Italy
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28
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van de Kamp JM, Mancini GM, Salomons GS. X-linked creatine transporter deficiency: clinical aspects and pathophysiology. J Inherit Metab Dis 2014; 37:715-33. [PMID: 24789340 DOI: 10.1007/s10545-014-9713-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/27/2014] [Accepted: 04/01/2014] [Indexed: 12/22/2022]
Abstract
Creatine transporter deficiency was discovered in 2001 as an X-linked cause of intellectual disability characterized by cerebral creatine deficiency. This review describes the current knowledge regarding creatine metabolism, the creatine transporter and the clinical aspects of creatine transporter deficiency. The condition mainly affects the brain while other creatine requiring organs, such as the muscles, are relatively spared. Recent studies have provided strong evidence that creatine synthesis also occurs in the brain, leading to the intriguing question of why cerebral creatine is deficient in creatine transporter deficiency. The possible mechanisms explaining the cerebral creatine deficiency are discussed. The creatine transporter knockout mouse provides a good model to study the disease. Over the past years several treatment options have been explored but no treatment has been proven effective. Understanding the pathogenesis of creatine transporter deficiency is of paramount importance in the development of an effective treatment.
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MESH Headings
- Amino Acid Metabolism, Inborn Errors/diagnosis
- Amino Acid Metabolism, Inborn Errors/drug therapy
- Amino Acid Metabolism, Inborn Errors/genetics
- Amino Acid Metabolism, Inborn Errors/pathology
- Animals
- Brain Diseases, Metabolic, Inborn/complications
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/physiopathology
- Creatine/deficiency
- Creatine/genetics
- Genetic Diseases, X-Linked/genetics
- Humans
- Intellectual Disability/etiology
- Intellectual Disability/genetics
- Membrane Transport Proteins/deficiency
- Membrane Transport Proteins/genetics
- Mental Retardation, X-Linked/complications
- Mental Retardation, X-Linked/genetics
- Mental Retardation, X-Linked/physiopathology
- Mice
- Plasma Membrane Neurotransmitter Transport Proteins/deficiency
- Plasma Membrane Neurotransmitter Transport Proteins/genetics
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Affiliation(s)
- Jiddeke M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands,
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29
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Dunbar M, Jaggumantri S, Sargent M, Stockler-Ipsiroglu S, van Karnebeek CDM. Treatment of X-linked creatine transporter (SLC6A8) deficiency: systematic review of the literature and three new cases. Mol Genet Metab 2014; 112:259-74. [PMID: 24953403 DOI: 10.1016/j.ymgme.2014.05.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Creatine transporter deficiency (CTD) is an X-linked inborn error of creatine metabolism characterized by reduced intra-cerebral creatine, developmental delay/intellectual disability, (ID), behavioral disturbance, seizures, and hypotonia in individuals harboring mutations in the SLC6A8 gene. Treatment for CTD includes supplementation with creatine, either alone or in combination with creatine precursors (arginine or glycine). Unlike other disorders of creatine metabolism, the efficacy of its treatment remains controversial. METHODS We present our systematic literature review (2001-2013) comprising 7 publications (case series/reports), collectively describing 25 patients who met the inclusion criteria, and 3 additional cases treated at our institution. Definitions were established and extracted data analyzed for cognitive ability, psychiatric and behavioral disturbances, epilepsy, and cerebral proton magnetic resonance spectroscopy measurements at pre- and post-treatment. RESULTS Treatment regimens varied among the 28 cases: 2 patients received creatine-monohydrate supplementation; 7 patients received L-arginine; 2 patients received creatine-monohydrate and L-arginine; and 17 patients received a combination of creatine-monohydrate, L-arginine and glycine. Median treatment duration was 34.6 months (range 3 months-5 years). Level of evidence was IV. A total of 10 patients (36%) demonstrated response to treatment, manifested by either an increase in cerebral creatine, or improved clinical parameters. Seven of the 28 patients had quantified pre- and post-treatment creatine, and it was significantly increased post-treatment. All of the patients with increased cerebral creatine also experienced clinical improvement. In addition, the majority of patients with clinical improvement had detectable cerebral creatine prior to treatment. 90% of the patients who improved were initiated on treatment before nine years of age. CONCLUSIONS Acknowledging the limitations of this systematic review, we conclude that a proportion of CTD patients show amenability to treatment-particularly milder cases with residual brain creatine, and therefore probable residual protein function. We propose systematic screening for CTD in patients with ID, to allow early initiation of treatment, which currently comprises oral creatine, arginine and/or glycine supplementation. Standardized monitoring for safety and evaluation of treatment effects are required in all patients. This study provides effectiveness on currently available treatment, which can be used to discern effectiveness of future interventions (e.g. cyclocreatine).
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Affiliation(s)
- Mary Dunbar
- Division of Pediatric Neurology, Department of Pediatrics, BC Children's Hospital, Vancouver, Canada
| | - Sravan Jaggumantri
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Child & Family Research Institute, University of British Columbia, Vancouver, Canada; Treatable Intellectual Disability Endeavor in British Columbia (TIDE-BC), Vancouver, Canada
| | - Michael Sargent
- Department of Radiology, BC Children's Hospital, Vancouver, Canada
| | - Sylvia Stockler-Ipsiroglu
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Child & Family Research Institute, University of British Columbia, Vancouver, Canada; Treatable Intellectual Disability Endeavor in British Columbia (TIDE-BC), Vancouver, Canada
| | - Clara D M van Karnebeek
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Child & Family Research Institute, University of British Columbia, Vancouver, Canada; Treatable Intellectual Disability Endeavor in British Columbia (TIDE-BC), Vancouver, Canada; Centre for Molecular Medicine and Therapeutics, Vancouver, Canada.
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30
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Nota B, Ndika JDT, van de Kamp JM, Kanhai WA, van Dooren SJM, van de Wiel MA, Pals G, Salomons GS. RNA Sequencing of Creatine Transporter (SLC6A8) Deficient Fibroblasts Reveals Impairment of the Extracellular Matrix. Hum Mutat 2014; 35:1128-35. [DOI: 10.1002/humu.22609] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 06/16/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Benjamin Nota
- Metabolic Unit; Department of Clinical Chemistry; VU University Medical Center; Neuroscience Campus Amsterdam; Amsterdam The Netherlands
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Joseph D. T. Ndika
- Metabolic Unit; Department of Clinical Chemistry; VU University Medical Center; Neuroscience Campus Amsterdam; Amsterdam The Netherlands
| | - Jiddeke M. van de Kamp
- Department of Clinical Genetics; VU University Medical Center; Amsterdam The Netherlands
| | - Warsha A. Kanhai
- Metabolic Unit; Department of Clinical Chemistry; VU University Medical Center; Neuroscience Campus Amsterdam; Amsterdam The Netherlands
| | - Silvy J. M. van Dooren
- Metabolic Unit; Department of Clinical Chemistry; VU University Medical Center; Neuroscience Campus Amsterdam; Amsterdam The Netherlands
| | - Mark A. van de Wiel
- Department of Epidemiology and Biostatistics; VU University Medical Center; Amsterdam The Netherlands
| | - Gerard Pals
- Department of Clinical Genetics; VU University Medical Center; Amsterdam The Netherlands
| | - Gajja S. Salomons
- Metabolic Unit; Department of Clinical Chemistry; VU University Medical Center; Neuroscience Campus Amsterdam; Amsterdam The Netherlands
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31
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Hautman ER, Kokenge AN, Udobi KC, Williams MT, Vorhees CV, Skelton MR. Female mice heterozygous for creatine transporter deficiency show moderate cognitive deficits. J Inherit Metab Dis 2014; 37:63-8. [PMID: 23716276 PMCID: PMC7025435 DOI: 10.1007/s10545-013-9619-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/04/2013] [Accepted: 04/30/2013] [Indexed: 11/29/2022]
Abstract
Creatine transporter (CrT) deficiency (CTD) is an X-linked disorder characterized by intellectual disability and speech delay. There have been reports that show female carriers have clinical symptoms. We have created CrT knockout (CrT(-/y)) mice in which males show severe cognitive deficits as a model of this disorder. The purpose of this study was to examine if the female carrier mice show cognitive deficits. Reductions in Cr levels as well as CrT transcript were observed in the brains of the female CrT(+/-) mice. CrT(+/-) mice show hyperactivity and increased latency to find the cued platform in the Morris water maze (MWM). CrT(+/-) female mice showed deficits in MWM hidden platform acquisition but not during reversal testing. Memory deficits on probe trials were observed during both phases. Novel object recognition memory and contextual fear memory were not affected in female CrT(+/-) mice. Female CrT(+/-) mice show moderate cognitive deficits, which is consistent with some of the human data. Female CrT(+/-) mice could prove to be beneficial in further understanding CTD and testing therapeutic approaches.
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Affiliation(s)
- Emily R Hautman
- Division of Neurology, MLC 7044 Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
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32
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Enrico A, Patrizia G, Luisa P, Alessandro P, Gianluigi L, Carlo G, Maurizio B. Electrophysiology and biochemical analysis of cyclocreatine uptake and effect in hippocampal slices. J Integr Neurosci 2013; 12:285-97. [DOI: 10.1142/s0219635213500155] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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33
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van de Kamp JM, Betsalel OT, Mercimek-Mahmutoglu S, Abulhoul L, Grünewald S, Anselm I, Azzouz H, Bratkovic D, de Brouwer A, Hamel B, Kleefstra T, Yntema H, Campistol J, Vilaseca MA, Cheillan D, D’Hooghe M, Diogo L, Garcia P, Valongo C, Fonseca M, Frints S, Wilcken B, von der Haar S, Meijers-Heijboer HE, Hofstede F, Johnson D, Kant SG, Lion-Francois L, Pitelet G, Longo N, Maat-Kievit JA, Monteiro JP, Munnich A, Muntau AC, Nassogne MC, Osaka H, Ounap K, Pinard JM, Quijano-Roy S, Poggenburg I, Poplawski N, Abdul-Rahman O, Ribes A, Arias A, Yaplito-Lee J, Schulze A, Schwartz CE, Schwenger S, Soares G, Sznajer Y, Valayannopoulos V, Van Esch H, Waltz S, Wamelink MMC, Pouwels PJW, Errami A, van der Knaap MS, Jakobs C, Mancini GM, Salomons GS. Phenotype and genotype in 101 males with X-linked creatine transporter deficiency. J Med Genet 2013; 50:463-72. [DOI: 10.1136/jmedgenet-2013-101658] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
The lack of creatine in the central nervous system causes a severe but treatable neurological disease. Three inherited defects, AGAT, GAMT, and CrT deficiency, compromising synthesis and transport of creatine have been discovered recently. Together these so-called creatine deficiency syndromes (CDS) might represent the most frequent metabolic disorders with a primarily neurological phenotype. Patients with CDS present with global developmental delays, mental retardation, speech impairment especially affecting active language, seizures, extrapyramidal movement disorder, and autism spectrum disorder. The two defects in the creatine synthesis, AGAT and GAMT, are autosomal recessive disorders. They can be diagnosed by analysis of the creatine, guanidinoacetate, and creatinine in body fluids. Treatment is available and, especially when introduced in infancy, has a good outcome. The defect of creatine transport, CrT, is an X-linked condition and perhaps the most frequent reasons for X-linked mental retardation. Diagnosis is made by an increased ratio of creatine to creatinine in urine, but successful treatment still needs to be explored. CDS are under-diagnosed because easy to miss in standard diagnostic workup. Because CDS represent a frequent cause of cognitive and neurological impairment that is treatable they warrant consideration in the workup for genetic mental retardation syndromes, for intractable seizure disorders, and for neurological diseases with a predominant lack of active speech.
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Affiliation(s)
- Andreas Schulze
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, Research Institute, Hospital for Sick Children and University of Toronto, Toronto, Canada.
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35
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Cheillan D, Curt MJC, Briand G, Salomons GS, Mention-Mulliez K, Dobbelaere D, Cuisset JM, Lion-François L, Portes VD, Chabli A, Valayannopoulos V, Benoist JF, Pinard JM, Simard G, Douay O, Deiva K, Afenjar A, Héron D, Rivier F, Chabrol B, Prieur F, Cartault F, Pitelet G, Goldenberg A, Bekri S, Gerard M, Delorme R, Tardieu M, Porchet N, Vianey-Saban C, Vamecq J. Screening for primary creatine deficiencies in French patients with unexplained neurological symptoms. Orphanet J Rare Dis 2012; 7:96. [PMID: 23234264 PMCID: PMC3552865 DOI: 10.1186/1750-1172-7-96] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 12/07/2012] [Indexed: 12/11/2022] Open
Abstract
A population of patients with unexplained neurological symptoms from six major French university hospitals was screened over a 28-month period for primary creatine disorder (PCD). Urine guanidinoacetate (GAA) and creatine:creatinine ratios were measured in a cohort of 6,353 subjects to identify PCD patients and compile their clinical, 1H-MRS, biochemical and molecular data. Six GAMT [N-guanidinoacetatemethyltransferase (EC 2.1.1.2)] and 10 X-linked creatine transporter (SLC6A8) but no AGAT (GATM) [L-arginine/glycine amidinotransferase (EC 2.1.4.1)] deficient patients were identified in this manner. Three additional affected sibs were further identified after familial inquiry (1 brother with GAMT deficiency and 2 brothers with SLC6A8 deficiency in two different families). The prevalence of PCD in this population was 0.25% (0.09% and 0.16% for GAMT and SLC6A8 deficiencies, respectively). Seven new PCD-causing mutations were discovered (2 nonsense [c.577C > T and c.289C > T] and 1 splicing [c.391 + 15G > T] mutations for the GAMT gene and, 2 missense [c.1208C > A and c.926C > A], 1 frameshift [c.930delG] and 1 splicing [c.1393-1G > A] mutations for the SLC6A8 gene). No hot spot mutations were observed in these genes, as all the mutations were distributed throughout the entire gene sequences and were essentially patient/family specific. Approximately one fifth of the mutations of SLC6A8, but not GAMT, were attributed to neo-mutation, germinal or somatic mosaicism events. The only SLC6A8-deficient female patient in our series presented with the severe phenotype usually characterizing affected male patients, an observation in agreement with recent evidence that is in support of the fact that this X-linked disorder might be more frequent than expected in the female population with intellectual disability.
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Affiliation(s)
- David Cheillan
- Hospices Civils de Lyon, Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Groupement Hospitalier Est, Bron, 69677, France
| | - Marie Joncquel-Chevalier Curt
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
| | - Gilbert Briand
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
- Mass Spectrometry Application Laboratory, University of Lille 2, Lille, 59045, France
| | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Karine Mention-Mulliez
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Jeanne de Flandres, CHRU Lille, Lille, 59037, France
| | - Dries Dobbelaere
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Jeanne de Flandres, CHRU Lille, Lille, 59037, France
| | - Jean-Marie Cuisset
- Service de Neurologie Infantile, Hôpital Roger Salengro, CHRU Lille, Lille, 59037, France
| | - Laurence Lion-François
- Service de neurologie pédiatrique, CHU de Lyon-GH Est - Hôpital Femme Mère Enfant, Bron Cedex, 69677, France
| | - Vincent Des Portes
- Service de neurologie pédiatrique, CHU de Lyon-GH Est - Hôpital Femme Mère Enfant, Bron Cedex, 69677, France
| | - Allel Chabli
- Laboratory of Biochemistry, Necker – Enfants Malades Hospital and Université Paris Descartes, Paris, 75015, France
| | - Vassili Valayannopoulos
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker des Enfants Malades and Université Paris Descartes, 149 rue de Sèvres, Paris, 75015, France
| | - Jean-François Benoist
- Département de Biochimie-Hormonologie, CHU Hôpital Robert Debré, Paris, 75019, France
| | - Jean-Marc Pinard
- Unité de Neurologie Pédiatrique, Département de Pédiatrie, Hôpital Raymond Poincare, Paris-IdF-Ouest University, Paris, France
| | - Gilles Simard
- Laboratoire de Biochimie et Biologie Moléculaire, CHU Angers, Angers, 49033, France
| | - Olivier Douay
- Laboratoire de Biochimie et Biologie Moléculaire, CHU Angers, Angers, 49033, France
| | - Kumaran Deiva
- Service de Neuropédiatrie - CHU de Bicêtre, Le Kremlin Bicêtre Cedex, 94275, France
| | - Alexandra Afenjar
- Service de Neuropédiatrie, Hôpital Armand Trousseau, Groupement hospitalier universitaire Est, Paris, 75012, France
| | - Delphine Héron
- Unité Fonctionnelle de Génétique Médicale AP-HP, Département de Génétique et Cytogénétique, Centre de Référence «Déficiences intellectuelles de causes rares », CRicm, UMR-S975, Groupe Hospitalier Pitié-Salpêtrière, Paris, F-75013, France
| | - François Rivier
- Neuropédiatrie, CHRU Montpellier, & Inserm U1046, Université Montpellier 1 & 2, Montpellier Cedex 5, 34295, France
| | - Brigitte Chabrol
- Service Neuropédiatrie, AP-HM Hôpital de la Timone, Marseille Cedex 5, 13385, France
| | - Fabienne Prieur
- Service de Génétique, CHU de Saint-Étienne Hôpital Nord, Saint-Etienne Cédex 2, 42055, France
| | - François Cartault
- Service de génétique Centre hospitalier Felix Guyon (Saint-Denis) Bellepierre, Saint-Denis cedex, 97405, France
| | - Gaëlle Pitelet
- Service de Neuropédiatrie, Hôpital de l’Archet 2, Nice Cedex 3, 06202, France
| | - Alice Goldenberg
- Service de Génétique Médicale, CHU Ch. Nicolle, Rouen Cedex, 76031, France
| | - Soumeya Bekri
- Institut de Biologie Clinique, CHU Ch. Nicolle, Rouen Cedex, 76031, France
| | - Marion Gerard
- Service de Génétique, CHU Clémenceau, Caen, 14033, France
| | - Richard Delorme
- Service de Pédopsychiatrie CHU Hôpital Robert Debré, Paris, 75019, France
| | - Marc Tardieu
- Service de Neuropédiatrie - CHU de Bicêtre, Le Kremlin Bicêtre Cedex, 94275, France
| | - Nicole Porchet
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
| | - Christine Vianey-Saban
- Hospices Civils de Lyon, Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Groupement Hospitalier Est, Bron, 69677, France
| | - Joseph Vamecq
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
- Inserm, Laboratoire Externe, Département du Prof. Nicole Porchet, HMNO, Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
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Leuzzi V, Mastrangelo M, Battini R, Cioni G. Inborn errors of creatine metabolism and epilepsy. Epilepsia 2012; 54:217-27. [DOI: 10.1111/epi.12020] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Braissant O. Creatine and guanidinoacetate transport at blood-brain and blood-cerebrospinal fluid barriers. J Inherit Metab Dis 2012; 35:655-64. [PMID: 22252611 DOI: 10.1007/s10545-011-9433-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/22/2011] [Accepted: 11/30/2011] [Indexed: 10/14/2022]
Abstract
While it was thought that most of cerebral creatine is of peripheral origin, AGAT and GAMT are well expressed in CNS where brain cells synthesize creatine. While the creatine transporter SLC6A8 is expressed by microcapillary endothelial cells (MCEC) at blood-brain barrier (BBB), it is absent from their surrounding astrocytes. This raised the concept that BBB has a limited permeability for peripheral creatine, and that the brain supplies a part of its creatine by endogenous synthesis. This review brings together the latest data on creatine and guanidinoacetate transport through BBB and blood-CSF barrier (BCSFB) with the clinical evidence of AGAT-, GAMT- and SLC6A8-deficient patients, in order to delineate a clearer view on the roles of BBB and BCSFB in the transport of creatine and guanidinoacetate between periphery and CNS, and on brain synthesis and transport of creatine. It shows that in physiological conditions, creatine is taken up by CNS from periphery through SLC6A8 at BBB, but in limited amounts, and that CNS also needs its own creatine synthesis. No uptake of guanidinoacetate from periphery occurs at BBB except under GAMT deficiency, but a net exit of guanidinoacetate seems to occur from CSF to blood at BCSFB, predominantly through the taurine transporter TauT.
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Affiliation(s)
- Olivier Braissant
- Inborn Errors of Metabolism, Service of Biomedicine, Lausanne University Hospital, Avenue Pierre-Decker 2, CI 02/33, CH-1011, Lausanne, Switzerland.
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Neuropsychological profile and clinical effects of arginine treatment in children with creatine transport deficiency. Orphanet J Rare Dis 2012; 7:43. [PMID: 22713831 PMCID: PMC3526552 DOI: 10.1186/1750-1172-7-43] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 02/27/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND SLC6A8, an X-linked gene, encodes the creatine transporter (CRTR) and its mutations lead to cerebral creatine (Cr) deficiency which results in mental retardation, speech and language delay, autistic-like behaviour and epilepsy (CRTR-D, OMIM 300352). CRTR-D represents the most frequent Cr metabolism disorder but, differently from Cr synthesis defects, that are partially reversible by oral Cr supplementation, does not respond to Cr treatment even if precociously administrated. The precursors of Cr are the non-essential amino acids Glycine (Gly) and Arginine (Arg), which have their own transporters at the brain-blood barrier level and, therefore, their supplementation appears an attractive and feasible therapeutic option aimed at stimulating Cr endogenous synthesis and, in this way, at overcoming the block of Cr transport within the brain. However, until now the effects of Arg and/or Gly supplementation on Cr brain levels and behaviour have been controversial. METHODS In this study five Italian male patients affected by CRTR-D were supplemented with oral L-Arg at a dosage of 300 mg/kg/day divided into 3 doses, for 24-36 months. Biochemical and plasmatic amino acids examinations and thyroid hormone dosages were periodically performed. Moreover, Proton and Phosphorus Magnetic Resonance Spectroscopy (MRS) was monitored during follow-up in concurrence with neuropsychological evaluations. RESULTS During L-Arg treatment a clinical improvement in motor skills and to a lesser extent in communication and attention was observed. In addition, all patients had a reduction in the number and frequency of epileptic seizures. Daily living skills appeared also to be positively influenced by L-Arg treatment. Moreover, Total Cr and especially PhosphoCr, evaluated by proton and phosphorus spectroscopy, showed a mild increase, although well below the normal range. CONCLUSION This study provides information to support the effectiveness of L-Arg supplement treatment in CTRT-D patients; in fact the syndromic pattern of cognitive and linguistic deficit presented by CRTR-D patients was partially altered by L-Arg supplementation especially at a qualitative clinical level. Oral L-Arg may represent not only a protective factor towards a further cognitive decline, but can lead to the acquisition of new skills.
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Carducci C, Carducci C, Santagata S, Adriano E, Artiola C, Thellung S, Gatta E, Robello M, Florio T, Antonozzi I, Leuzzi V, Balestrino M. In vitro study of uptake and synthesis of creatine and its precursors by cerebellar granule cells and astrocytes suggests some hypotheses on the physiopathology of the inherited disorders of creatine metabolism. BMC Neurosci 2012; 13:41. [PMID: 22536786 PMCID: PMC3355046 DOI: 10.1186/1471-2202-13-41] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 04/26/2012] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND The discovery of the inherited disorders of creatine (Cr) synthesis and transport in the last few years disclosed the importance of blood Cr supply for the normal functioning of the brain. These putatively rare diseases share a common pathogenetic mechanism (the depletion of brain Cr) and similar phenotypes characterized by mental retardation, language disturbances, seizures and movement disorders. In the effort to improve our knowledge on the mechanisms regulating Cr pool inside the nervous tissue, Cr transport and synthesis and related gene transcripts were explored in primary cultures of rat cerebellar granule cells and astrocytes. METHODS Cr uptake and synthesis were explored in vitro by incubating monotypic primary cultures of rat type I astrocytes and cerebellar granule cells with: a) D3-Creatine (D3Cr) and D3Cr plus β-guanidinopropionate (GPA, an inhibitor of Cr transporter), and b) labelled precursors of Guanidinoacetate (GAA) and Cr (Arginine, Arg; Glycine, Gly). Intracellular D3Cr and labelled GAA and Cr were assessed by ESI-MS/MS. Creatine transporter (CT1), L-arginine:glycine amidinotransferase (AGAT), and S-adenosylmethionine:guanidinoacetate N-methyltransferase (GAMT) gene expression was assessed in the same cells by real time PCR. RESULTS D3Cr signal was extremely high in cells incubated with this isotope (labelled/unlabelled Cr ratio reached about 10 and 122, respectively in cerebellar granule cells and astrocytes) and was reduced by GPA. Labelled Arg and Gly were taken up by the cells and incorporated in GAA, whose concentration paralleled that of these precursors both in the extracellular medium and inside the cells (astrocytes). In contrast, the increase of labelled Cr was relatively much more limited since labelled Cr after precursors' supplementation did not exceed 2,7% (cerebellar granule cells) and 21% (astrocytes) of unlabelled Cr. Finally, AGAT, GAMT and SLC6A8 were expressed in both kind of cells. CONCLUSIONS Our results confirm that both neurons and astrocytes have the capability to synthesize and uptake Cr, and suggest that at least in vitro intracellular Cr can increase to a much greater extent through uptake than through de novo synthesis. Our results are compatible with the clinical observations that when the Cr transporter is defective, intracellular Cr is absent despite the brain should be able to synthesize it. Further research is needed to fully understand to what extent our results reflect the in vivo situation.
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Affiliation(s)
- Claudia Carducci
- Department of Experimental Medicine, La Sapienza Università di Roma, Viale del Policlinico 155, Rome 00161, Italy
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Betsalel OT, Pop A, Rosenberg EH, Fernandez-Ojeda M, Jakobs C, Salomons GS. Detection of variants in SLC6A8 and functional analysis of unclassified missense variants. Mol Genet Metab 2012; 105:596-601. [PMID: 22281021 DOI: 10.1016/j.ymgme.2011.12.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/28/2011] [Accepted: 12/28/2011] [Indexed: 10/14/2022]
Abstract
Creatine transporter deficiency is an X-linked disorder caused by mutations in the SLC6A8 gene. Currently, 38 pathogenic, including 15 missense variants, are reported. In this study, we report 33 novel, including 6 missense variants. To classify all known missense variants, we transfected creatine deficient fibroblasts with the SLC6A8 ORF containing one of the unique variants and tested their ability to restore creatine uptake. This resulted in the definitive classification of 2 non-disease associated and 19 pathogenic variants of which 3 have residual activity. Furthermore, we report the development and validation of a novel DHPLC method for the detection of heterozygous SLC6A8 variants. The method was validated by analysis of DNAs that in total contained 67 unique variants of which 66 could be detected. Therefore, this rapid screening method may prove valuable for the analysis of large cohorts of females with mild intellectual disability of unknown etiology, since in this group heterozygous SLC6A8 mutations may be detected. DHPLC proved also to be important for the detection of somatic mosaicism in mothers of patients who have a pathogenic mutation in SLC6A8. All variants reported in the present and previous studies are included in the Leiden Open Source Variant Database (LOVD) of SLC6A8 (www.LOVD.nl/SLC6A8).
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Affiliation(s)
- Ofir T Betsalel
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
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41
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Stevenson RE, Holden KR, Rogers RC, Schwartz CE. Seizures and X-linked intellectual disability. Eur J Med Genet 2012; 55:307-12. [PMID: 22377486 DOI: 10.1016/j.ejmg.2012.01.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 01/28/2012] [Indexed: 11/28/2022]
Abstract
Intellectual disability occurs as an isolated X-linked trait and as a component of recognizable X-linked syndromes in the company of somatic, metabolic, neuromuscular, or behavioral abnormalities. Seizures accompany intellectual disability in almost half of these X-linked disorders. The spectrum of seizures found in the X-linked intellectual disability syndromes is broad, varying in time of onset, type of seizure, and response to anticonvulsant therapy. The majority of the genes associated with XLID and seizures have now been identified.
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Affiliation(s)
- Roger E Stevenson
- Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29646, USA.
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Phenotypic variability in a portuguese family with x-linked creatine transport deficiency. Pediatr Neurol 2012; 46:39-41. [PMID: 22196490 DOI: 10.1016/j.pediatrneurol.2011.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/13/2011] [Accepted: 10/05/2011] [Indexed: 11/21/2022]
Abstract
Cerebral creatine transporter deficiency, attributable to mutations in the SLC6A8 gene, causes X-linked mental retardation, language delay, epilepsy, and autistic features. In contrast with creatine synthesis defects, the vast majority of patients with SLC6A8 deficiency do not respond to treatment. We describe a Portuguese family with a mutation (c.456C>T; p.Gln486X) in the SL6CA8 gene: two adult monozygotic twin brothers, with psychomotor delay and severe speech impairment. The family also includes their maternal half-sister with psychomotor retardation, predominantly in language, and their mentally retarded mother. This family illustrates the remarkable phenotypic variability in this condition. Investigation of creatine metabolism is mandatory in patients with developmental delay of unknown etiology, to detect this condition.
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Valayannopoulos V, Boddaert N, Chabli A, Barbier V, Desguerre I, Philippe A, Afenjar A, Mazzuca M, Cheillan D, Munnich A, de Keyzer Y, Jakobs C, Salomons GS, de Lonlay P. Treatment by oral creatine, L-arginine and L-glycine in six severely affected patients with creatine transporter defect. J Inherit Metab Dis 2012; 35:151-7. [PMID: 21660517 DOI: 10.1007/s10545-011-9358-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 05/11/2011] [Accepted: 05/25/2011] [Indexed: 11/24/2022]
Abstract
BACKGROUND X-linked cerebral creatine deficiency is caused by the deficiency of the creatine transporter (CTP) encoded by the SLC6A8 gene. PATIENTS AND METHODS We report here a series of six patients with severe CTP deficiency, four males and two females; clinical presentations include mild to severe mental retardation (6/6), associated with psychiatric symptoms (5/6: autistic behaviour, chronic hallucinatory psychosis), seizures (2/6) and muscular symptoms (2/4 males). Diagnosis was suspected upon elevated urinary creatine/creatinine (except in one of the female patients) and on a markedly decreased creatine peak on magnetic resonance spectroscopy (MRS). Diagnosis was confirmed by molecular analysis that identified four novel mutations not reported so far, including a mutation found twice in two male patients. All patients were treated successively and according to the same protocol by creatine alone then combined to its precursors, L-glycine and L-arginine for 42 months. RESULTS AND CONCLUSION In our patients, creatine supplementation alone or with its precursors L-glycine and L-arginine showed benefit only in the muscular symptoms of the disease and no improvement in the cognitive and psychiatric manifestations and did not modify brain creatine content on MRS of male and female CTP deficient patients. New treatment strategies are required including creatine derivatives transported independently from CTP or using alternative pathways and transporters.
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Affiliation(s)
- Vassili Valayannopoulos
- Reference Center for Inherited Metabolic Disorders (MaMEA), Necker-Enfants Malades Hospital, Paris Descartes University, 149 Rue de Sèvres, 75743 Paris Cedex, France.
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44
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van de Kamp JM, Pouwels PJW, Aarsen FK, ten Hoopen LW, Knol DL, de Klerk JB, de Coo IF, Huijmans JGM, Jakobs C, van der Knaap MS, Salomons GS, Mancini GMS. Long-term follow-up and treatment in nine boys with X-linked creatine transporter defect. J Inherit Metab Dis 2012; 35:141-9. [PMID: 21556832 PMCID: PMC3249187 DOI: 10.1007/s10545-011-9345-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/05/2011] [Accepted: 04/19/2011] [Indexed: 10/26/2022]
Abstract
The creatine transporter (CRTR) defect is a recently discovered cause of X-linked intellectual disability for which treatment options have been explored. Creatine monotherapy has not proved effective, and the effect of treatment with L-arginine is still controversial. Nine boys between 8 months and 10 years old with molecularly confirmed CRTR defect were followed with repeated (1)H-MRS and neuropsychological assessments during 4-6 years of combination treatment with creatine monohydrate, L-arginine, and glycine. Treatment did not lead to a significant increase in cerebral creatine content as observed with H(1)-MRS. After an initial improvement in locomotor and personal-social IQ subscales, no lasting clinical improvement was recorded. Additionally, we noticed an age-related decline in IQ subscales in boys affected with the CRTR defect.
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Affiliation(s)
- Jiddeke M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands.
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45
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van de Kamp JM, Mancini GMS, Pouwels PJW, Betsalel OT, van Dooren SJM, de Koning I, Steenweg ME, Jakobs C, van der Knaap MS, Salomons GS. Clinical features and X-inactivation in females heterozygous for creatine transporter defect. Clin Genet 2011; 79:264-72. [PMID: 20528887 DOI: 10.1111/j.1399-0004.2010.01460.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The creatine transporter defect is an X-linked cause of mental retardation. We investigated the clinical features and pattern of X-inactivation in a Dutch cohort of eight female heterozygotes. We show that symptoms of the creatine transporter defect (mental retardation, learning difficulties, and constipation) can be present in female heterozygotes. We further show that the diagnosis in females is not straightforward: (i) The creatine/creatinine ratio in urine was elevated only in three of eight females. (ii) Although as a group the females had a significantly decreased cerebral creatine concentration, individual females had creatine concentrations overlapping with normal controls. (iii) Skewed X-inactivation was found in the cultured fibroblasts, in favour of either the mutated or the wild-type allele, leading to either deficient or normal results in the creatine uptake studies in fibroblasts. Thus, screening by these tests is unreliable for the diagnosis. In addition, we found no consistent skewing of the X-inactivation in peripheral tissues indicating that there is no selection against the creatine transporter defect. We conclude that testing for creatine transporter defect should be considered in females with (mild) mental retardation. Screening by DNA analysis of the SLC6A8 gene is recommended.
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Affiliation(s)
- J M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands.
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46
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Braissant O, Henry H, Béard E, Uldry J. Creatine deficiency syndromes and the importance of creatine synthesis in the brain. Amino Acids 2011; 40:1315-24. [DOI: 10.1007/s00726-011-0852-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 11/25/2010] [Indexed: 10/18/2022]
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Skelton MR, Schaefer TL, Graham DL, Degrauw TJ, Clark JF, Williams MT, Vorhees CV. Creatine transporter (CrT; Slc6a8) knockout mice as a model of human CrT deficiency. PLoS One 2011; 6:e16187. [PMID: 21249153 PMCID: PMC3020968 DOI: 10.1371/journal.pone.0016187] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 12/09/2010] [Indexed: 11/18/2022] Open
Abstract
Mutations in the creatine (Cr) transporter (CrT; Slc6a8) gene lead to absence of brain Cr and intellectual disabilities, loss of speech, and behavioral abnormalities. To date, no mouse model of CrT deficiency exists in which to understand and develop treatments for this condition. The purpose of this study was to generate a mouse model of human CrT deficiency. We created mice with exons 2–4 of Slc6a8 flanked by loxP sites and crossed these to Cre:CMV mice to create a line of ubiquitous CrT knockout expressing mice. Mice were tested for learning and memory deficits and assayed for Cr and neurotransmitter levels. Male CrT−/y (affected) mice lack Cr in the brain and muscle with significant reductions of Cr in other tissues including heart and testes. CrT−/y mice showed increased path length during acquisition and reversal learning in the Morris water maze. During probe trials, CrT−/y mice showed increased average distance from the platform site. CrT−/y mice showed reduced novel object recognition and conditioned fear memory compared to CrT+/y. CrT−/y mice had increased serotonin and 5-hydroxyindole acetic acid in the hippocampus and prefrontal cortex. Ubiquitous CrT knockout mice have learning and memory deficits resembling human CrT deficiency and this model should be useful in understanding this disorder.
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Affiliation(s)
- Matthew R Skelton
- Division of Neurology, Cincinnati Children's Research Foundation, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.
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48
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Mercimek-Mahmutoglu S, Connolly MB, Poskitt KJ, Horvath GA, Lowry N, Salomons GS, Casey B, Sinclair G, Davis C, Jakobs C, Stockler-Ipsiroglu S. Treatment of intractable epilepsy in a female with SLC6A8 deficiency. Mol Genet Metab 2010; 101:409-12. [PMID: 20846889 DOI: 10.1016/j.ymgme.2010.08.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/14/2010] [Accepted: 08/14/2010] [Indexed: 10/19/2022]
Abstract
A female heterozygous for a novel, disease causing, missense mutation in the X-linked cerebral creatine transporter (SLC6A8) gene (c.1067G>T, p.Gly356Val) presented with intractable epilepsy, mild intellectual disability and moderately reduced cerebral creatine levels. Treatment with creatine monohydrate, to enhance cerebral creatine transport, combined with L-arginine and L-glycine, to enhance cerebral creatine synthesis, resulted in complete resolution of seizures. Heterozygous SLC6A8 deficiency is a potentially treatable condition and should be considered in females with intractable epilepsy and developmental delay/intellectual disability.
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Affiliation(s)
- Saadet Mercimek-Mahmutoglu
- Department of Pediatrics, Division of Biochemical Diseases, British Columbia Children's Hospital, UBC, Canada
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49
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Béard E, Braissant O. Synthesis and transport of creatine in the CNS: importance for cerebral functions. J Neurochem 2010; 115:297-313. [DOI: 10.1111/j.1471-4159.2010.06935.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Alcaide P, Rodriguez-Pombo P, Ruiz-Sala P, Ferrer I, Castro P, Ruiz Martin Y, Merinero B, Ugarte M. A new case of creatine transporter deficiency associated with mild clinical phenotype and a novel mutation in the SLC6A8 gene. Dev Med Child Neurol 2010; 52:215-7. [PMID: 20002129 DOI: 10.1111/j.1469-8749.2009.03480.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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