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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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2
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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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3
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Faulkner P, Paioni SL, Kozhuharova P, Orlov N, Lythgoe DJ, Daniju Y, Morgenroth E, Barker H, Allen P. Relationship between depression, prefrontal creatine and grey matter volume. J Psychopharmacol 2021; 35:1464-1472. [PMID: 34697970 PMCID: PMC8652356 DOI: 10.1177/02698811211050550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Depression and low mood are leading contributors to disability worldwide. Research indicates that clinical depression may be associated with low creatine concentrations in the brain and low prefrontal grey matter volume. Because subclinical depression also contributes to difficulties in day-to-day life, understanding the neural mechanisms of depressive symptoms in all individuals, even at a subclinical level, may aid public health. METHODS Eighty-four young adult participants completed the Depression, Anxiety and Stress Scale (DASS) to quantify severity of depression, anxiety and stress, and underwent 1H-Magnetic Resonance Spectroscopy of the medial prefrontal cortex and structural magnetic resonance imaging (MRI) to determine whole-brain grey matter volume. RESULTS/OUTCOMES DASS depression scores were negatively associated (a) with concentrations of creatine (but not other metabolites) in the prefrontal cortex and (b) with grey matter volume in the right superior medial frontal gyrus. Medial prefrontal creatine concentrations and right superior medial frontal grey matter volume were positively correlated. DASS anxiety and DASS stress scores were not related to prefrontal metabolite concentrations or whole-brain grey matter volume. CONCLUSIONS/INTERPRETATIONS This study provides preliminary evidence from a representative group of individuals who exhibit a range of depression levels that prefrontal creatine and grey matter volume are negatively associated with depression. While future research is needed to fully understand this relationship, these results provide support for previous findings, which indicate that increasing creatine concentrations in the prefrontal cortex may improve mood and well-being.
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Affiliation(s)
- Paul Faulkner
- Department of Psychology, Whitelands College, University of Roehampton, London, UK
- Department of Psychology, University of Roehampton, London, UK
- Combined Universities Brain Imaging Centre, London, UK
| | | | | | - Natasza Orlov
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - David J Lythgoe
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Yusuf Daniju
- Department of Psychology, University of Roehampton, London, UK
| | - Elenor Morgenroth
- Department of Psychology, University of Roehampton, London, UK
- Combined Universities Brain Imaging Centre, London, UK
- Institute of Bioengineering, Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland
| | - Holly Barker
- Department of Psychology, University of Roehampton, London, UK
- Combined Universities Brain Imaging Centre, London, UK
| | - Paul Allen
- Department of Psychology, University of Roehampton, London, UK
- Combined Universities Brain Imaging Centre, London, UK
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
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4
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Archibald J, MacMillan EL, Graf C, Kozlowski P, Laule C, Kramer JLK. Metabolite activity in the anterior cingulate cortex during a painful stimulus using functional MRS. Sci Rep 2020; 10:19218. [PMID: 33154474 PMCID: PMC7645766 DOI: 10.1038/s41598-020-76263-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/14/2020] [Indexed: 02/07/2023] Open
Abstract
To understand neurochemical brain responses to pain, proton magnetic resonance spectroscopy (1H-MRS) is used in humans in vivo to examine various metabolites. Recent MRS investigations have adopted a functional approach, where acquisitions of MRS are performed over time to track task-related changes. Previous studies suggest glutamate is of primary interest, as it may play a role during cortical processing of noxious stimuli. The objective of this study was to examine the metabolic effect (i.e., glutamate) in the anterior cingulate cortex during noxious stimulation using fMRS. The analysis addressed changes in glutamate and glutamate + glutamine (Glx) associated with the onset of pain, and the degree by which fluctuations in metabolites corresponded with continuous pain outcomes. Results suggest healthy participants undergoing tonic noxious stimulation demonstrated increased concentrations of glutamate and Glx at the onset of pain. Subsequent reports of pain were not accompanied by corresponding changes in glutamate of Glx concentrations. An exploratory analysis on sex revealed large effect size changes in glutamate at pain onset in female participants, compared with medium-sized effects in male participants. We propose a role for glutamate in the ACC related to the detection of a noxious stimulus.
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Affiliation(s)
- J Archibald
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada.
- Department of Experimental Medicine, University of British Columbia, Vancouver, Canada.
| | - E L MacMillan
- Department of Radiology, University of British Columbia, Vancouver, Canada
- ImageTech Lab, Simon Fraser University, Surrey, Canada
- Philips Healthcare Canada, Markham, Canada
| | - C Graf
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - P Kozlowski
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
- Hughill Center, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - C Laule
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
- Hughill Center, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
- Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - J L K Kramer
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Djavad Mowafaghian Center for Brain Health (DMCH), Vancouver, Canada
- Hughill Center, Vancouver, Canada
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Farr CV, El-Kasaby A, Freissmuth M, Sucic S. The Creatine Transporter Unfolded: A Knotty Premise in the Cerebral Creatine Deficiency Syndrome. Front Synaptic Neurosci 2020; 12:588954. [PMID: 33192443 PMCID: PMC7644880 DOI: 10.3389/fnsyn.2020.588954] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/18/2020] [Indexed: 12/16/2022] Open
Abstract
Creatine provides cells with high-energy phosphates for the rapid reconstitution of hydrolyzed adenosine triphosphate. The eponymous creatine transporter (CRT1/SLC6A8) belongs to a family of solute carrier 6 (SLC6) proteins. The key role of CRT1 is to translocate creatine across tissue barriers and into target cells, such as neurons and myocytes. Individuals harboring mutations in the coding sequence of the human CRT1 gene develop creatine transporter deficiency (CTD), one of the pivotal underlying causes of cerebral creatine deficiency syndrome. CTD encompasses an array of clinical manifestations, including severe intellectual disability, epilepsy, autism, development delay, and motor dysfunction. CTD is characterized by the absence of cerebral creatine, which implies an indispensable role for CRT1 in supplying the brain cells with creatine. CTD-associated variants dramatically reduce or abolish creatine transport activity by CRT1. Many of these are point mutations that are known to trigger folding defects, leading to the retention of encoded CRT1 proteins in the endoplasmic reticulum and precluding their delivery to the cell surface. Misfolding of several related SLC6 transporters also gives rise to detrimental pathologic conditions in people; e.g., mutations in the dopamine transporter induce infantile parkinsonism/dystonia, while mutations in the GABA transporter 1 cause treatment-resistant epilepsy. In some cases, folding defects are amenable to rescue by small molecules, known as pharmacological and chemical chaperones, which restore the cell surface expression and transport activity of the previously non-functional proteins. Insights from the recent molecular, animal and human case studies of CTD add toward our understanding of this complex disorder and reveal the wide-ranging effects elicited upon CRT1 dysfunction. This grants novel therapeutic prospects for the treatment of patients afflicted with CTD, e.g., modifying the creatine molecule to facilitate CRT1-independent entry into brain cells, or correcting folding-deficient and loss-of-function CTD variants using pharmacochaperones and/or allosteric modulators. The latter justifies a search for additional compounds with a capacity to correct mutation-specific defects.
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Affiliation(s)
| | | | | | - Sonja Sucic
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Abdulla ZI, Pennington JL, Gutierrez A, Skelton MR. Creatine transporter knockout mice (Slc6a8) show increases in serotonin-related proteins and are resilient to learned helplessness. Behav Brain Res 2019; 377:112254. [PMID: 31542396 DOI: 10.1016/j.bbr.2019.112254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 12/11/2022]
Abstract
Approximately 20% of adults in the U.S. will experience an affective disorder during their life. While it is well established that serotonin (5-HT) is a crucial factor in mood, impaired cellular bioenergetics are also implicated. Creatine (Cr), through the Cr/Phospho-Cr (PCr) shuttle, maintains high ATP concentrations in the neuron. This system may be implicated in the etiology of affective disorders, as reduced Cr, PCr, and ATP are often seen in the brains of affected patients. To address this issue, Cr transporter (Crt) deficient male mice (Slc6a8-/y) and female mice heterozygous for Crt expression (Slc6a8+/-) were used to evaluate how a Cr deficient system would alter affective-like behaviors. Slc6a8-/y and Slc6a8+/- mice had faster escape latencies in learned helplessness, indicating a potential resilience to behavioral despair. Slc6a8-/y had decrease latency to immobility in the tail-suspension test and Slc6a8+/- had increased open entries in elevated zero maze, but all other variables matched those of wildtype mice, however. Slc6a8-/y mice have increased 5-hydroxyindoleacetic acid content in the hippocampus and striatum and increased monoamine oxidase protein and tryptophan hydroxylase-2 protein content in the hippocampus, while 5-HT levels are unchanged. This indicates an alteration to the 5-HTergic system in Cr deficient mice. Our results indicate that Cr plays a complex role in affective disorders and 5-HT, warranting further investigation.
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Affiliation(s)
- Zuhair I Abdulla
- Department of Pediatrics, University of Cincinnati College of Medicine, USA; Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
| | - Jordan L Pennington
- Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
| | - Arnold Gutierrez
- Department of Pediatrics, University of Cincinnati College of Medicine, USA; Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
| | - Matthew R Skelton
- Department of Pediatrics, University of Cincinnati College of Medicine, USA; Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA.
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7
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Udobi KC, Delcimmuto N, Kokenge AN, Abdulla ZI, Perna MK, Skelton MR. Deletion of the creatine transporter gene in neonatal, but not adult, mice leads to cognitive deficits. J Inherit Metab Dis 2019; 42:966-974. [PMID: 31209903 PMCID: PMC6739135 DOI: 10.1002/jimd.12137] [Citation(s) in RCA: 12] [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: 03/15/2019] [Revised: 05/15/2019] [Accepted: 06/13/2019] [Indexed: 12/20/2022]
Abstract
Creatine (Cr) is a guanidino compound that provides readily available phosphate pools for the regeneration of spent adenosine triphosphate (ATP). The lack of brain Cr causes moderate to severe intellectual disability, language impairment, and epilepsy. The most prevalent cause of Cr deficiency are mutations in the X-linked SLC6A8 (Creatine transporter; CrT) gene, known as CrT deficiency (CTD). One of the most critical areas that need to be addressed is whether Cr is necessary for brain development. To address this concern, the Slc6a8 gene was knocked out in either neonatal (postnatal day (P)5) or adult (P60) mice using a tamoxifen-inducible Cre recombinase driven by the human ubiquitin C (UBC) promoter. Mice were tested in the Morris water maze, novel, object recognition, and conditioned fear 60 days after Slc6a8 deletion. In addition, overnight locomotor activity was analyzed. Mice that had the gene deleted on P5 showed deficits in the Morris water maze and novel object recognition, while there were no deficits in P60 knockout mice. Interestingly, the P5 knockout mice showed hyperactivity during the dark phase; however, when examining control mice, the effect was due to the administration of tamoxifen from P5 to 10. Taken together, the results of this study show that Cr is necessary during periods of brain development involved in spatial and object learning. This study also highlights the continued importance of using proper control groups for behavioral testing.
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8
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Pazini FL, Cunha MP, Rodrigues ALS. The possible beneficial effects of creatine for the management of depression. Prog Neuropsychopharmacol Biol Psychiatry 2019; 89:193-206. [PMID: 30193988 DOI: 10.1016/j.pnpbp.2018.08.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 08/17/2018] [Accepted: 08/28/2018] [Indexed: 01/23/2023]
Abstract
Depression, a highly prevalent neuropsychiatric disorder worldwide, causes a heavy burden for the society and is associated with suicide risk. The treatment of this disorder remains a challenge, since currently available antidepressants provide a slow and, often, incomplete response and cause several side effects that contribute to diminish the adhesion of patients to treatment. In this context, several nutraceuticals have been investigated regarding their possible beneficial effects for the management of this neuropsychiatric disorder. Creatine stands out as a supplement frequently used for ergogenic purpose, but it also is a neuroprotective compound with potential to treat or mitigate a broad range of central nervous systems diseases, including depression. This review presents preclinical and clinical evidence that creatine may exhibit antidepressant properties. The focus is given on the possible molecular mechanisms underlying its effects based on the results obtained with different animal models of depression. Finally, evidence obtained in animal models of depression addressing the possibility that creatine may produce rapid antidepressant effect, similar to ketamine, are also presented and discussed.
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Affiliation(s)
- Francis L Pazini
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Mauricio P Cunha
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Ana Lúcia S Rodrigues
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
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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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10
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Udobi KC, Kokenge AN, Hautman ER, Ullio G, Coene J, Williams MT, Vorhees CV, Mabondzo A, Skelton MR. Cognitive deficits and increases in creatine precursors in a brain-specific knockout of the creatine transporter gene Slc6a8. GENES BRAIN AND BEHAVIOR 2018; 17:e12461. [PMID: 29384270 DOI: 10.1111/gbb.12461] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 01/16/2018] [Accepted: 01/27/2018] [Indexed: 12/30/2022]
Abstract
Creatine transporter (CrT; SLC6A8) deficiency (CTD) is an X-linked disorder characterized by severe cognitive deficits, impairments in language and an absence of brain creatine (Cr). In a previous study, we generated floxed Slc6a8 (Slc6a8 flox ) mice to create ubiquitous Slc6a8 knockout (Slc6a8-/y ) mice. Slc6a8-/y mice lacked whole body Cr and exhibited cognitive deficits. While Slc6a8-/y mice have a similar biochemical phenotype to CTD patients, they also showed a reduction in size and reductions in swim speed that may have contributed to the observed deficits. To address this, we created brain-specific Slc6a8 knockout (bKO) mice by crossing Slc6a8flox mice with Nestin-cre mice. bKO mice had reduced cerebral Cr levels while maintaining normal Cr levels in peripheral tissue. Interestingly, brain concentrations of the Cr synthesis precursor guanidinoacetic acid were increased in bKO mice. bKO mice had longer latencies and path lengths in the Morris water maze, without reductions in swim speed. In accordance with data from Slc6a8 -/y mice, bKO mice showed deficits in novel object recognition as well as contextual and cued fear conditioning. bKO mice were also hyperactive, in contrast with data from the Slc6a8 -/y mice. The results show that the loss of cerebral Cr is responsible for the learning and memory deficits seen in ubiquitous Slc6a8-/y mice.
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Affiliation(s)
- K C Udobi
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio
| | - A N Kokenge
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio
| | - E R Hautman
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio
| | - G Ullio
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, Université Paris Saclay, Gif-sur-Yvette Cedex, France
| | - J Coene
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, Université Paris Saclay, Gif-sur-Yvette Cedex, France
| | - M T Williams
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio
| | - C V Vorhees
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio
| | - A Mabondzo
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, Université Paris Saclay, Gif-sur-Yvette Cedex, France
| | - M R Skelton
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.,Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio
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11
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Laboratory diagnosis of creatine deficiency syndromes: a technical standard and guideline of the American College of Medical Genetics and Genomics. Genet Med 2017; 19:256-263. [PMID: 28055022 DOI: 10.1038/gim.2016.203] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 01/29/2023] Open
Abstract
Disclaimer: These ACMG Standards and Guidelines are intended as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these standards and guidelines is voluntary and does not necessarily assure a successful medical outcome. These Standards and Guidelines should not be considered inclusive of all proper procedures and tests or exclusive of others that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, clinical laboratory geneticists should apply their professional judgment to the specific circumstances presented by the patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient's record the rationale for the use of a particular procedure or test, whether or not it is in conformance with these Standards and Guidelines. They also are advised to take notice of the date any particular guideline was adopted, and to consider other relevant medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures.Cerebral creatine deficiency syndromes are neurometabolic conditions characterized by intellectual disability, seizures, speech delay, and behavioral abnormalities. Several laboratory methods are available for preliminary and confirmatory diagnosis of these conditions, including measurement of creatine and related metabolites in biofluids using liquid chromatography-tandem mass spectrometry or gas chromatography-mass spectrometry, enzyme activity assays in cultured cells, and DNA sequence analysis. These guidelines are intended to standardize these procedures to help optimize the diagnosis of creatine deficiency syndromes. While biochemical methods are emphasized, considerations for confirmatory molecular testing are also discussed, along with variables that influence test results and interpretation.Genet Med 19 2, 256-263.
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12
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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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13
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Abstract
Creatine deficiency syndromes are a group of disorders of creatine (Cr) synthesis and transport characterized by intellectual disability, language delay, epilepsy, autism spectrum disorder, and movement disorders secondary to decrease of Cr concentration in the brain. Synthesis defects are treatable, therefore an early diagnosis and treatment is essential. The aim of this article is to review the Cr metabolism and function in the central nervous system. We describe the optimal diagnostic protocol in Cr deficiency syndromes based on biochemical methods, neuroradiological (1H-MRS), and molecular analysis. Finally, a treatment approach of the different Cr deficiency syndromes is described.
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Affiliation(s)
- Carmen Fons
- From the Pediatric Neurology Department, Sant Joan de Déu Hospital, Barcelona University, Barcelona, Spain.
| | - Jaume Campistol
- From the Pediatric Neurology Department, Sant Joan de Déu Hospital, Barcelona University, Barcelona, Spain
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14
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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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15
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Hanna-El-Daher L, Béard E, Henry H, Tenenbaum L, Braissant O. Mild guanidinoacetate increase under partial guanidinoacetate methyltransferase deficiency strongly affects brain cell development. Neurobiol Dis 2015; 79:14-27. [DOI: 10.1016/j.nbd.2015.03.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/27/2015] [Accepted: 03/31/2015] [Indexed: 11/15/2022] Open
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16
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Lowe MTJ, Faull RLM, Christie DL, Waldvogel HJ. Distribution of the creatine transporter throughout the human brain reveals a spectrum of creatine transporter immunoreactivity. J Comp Neurol 2014; 523:699-725. [PMID: 25159005 DOI: 10.1002/cne.23667] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 08/20/2014] [Accepted: 08/20/2014] [Indexed: 12/27/2022]
Abstract
Creatine is a molecule that supports energy metabolism in cells. It is carried across the plasma membrane by the creatine transporter. There has been recent interest in creatine for its neuroprotective effects in neurodegenerative diseases and its potential as a therapeutic agent. This study represents the first systematic investigation of the distribution of the creatine transporter in the human brain. We have used immunohistochemical techniques to map out its location and the intensity of staining. The transporter was found to be strongly expressed, especially in the large projection neurons of the brain and spinal cord. These include the pyramidal neurons in the cerebral cortex, Purkinje cells in the cerebellar cortex, and motor neurons of the somatic motor and visceromotor cranial nerve nuclei and the ventral horn of the spinal cord. Many other neurons in the brain also had some degree of creatine transporter immunoreactivity. By contrast, the medium spiny neurons of the striatum and the catecholaminergic neurons of the substantia nigra and locus coeruleus, which are implicated in neurodegenerative diseases, showed a very low to almost absent level of immunoreactivity for the transporter. We propose that the distribution may reflect the energy consumption by different cell types and that the extent of creatine transporter expression is proportional to the cell's energy requirements. Furthermore, the distribution indicates that supplemented creatine would be widely taken up by brain cells, although possibly less by those cells that degenerate in Huntington's and Parkinson's diseases.
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Affiliation(s)
- Matthew T J Lowe
- Centre for Brain Research and Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, 1142, New Zealand
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17
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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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18
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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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Braissant O. GAMT deficiency: 20 years of a treatable inborn error of metabolism. Mol Genet Metab 2014; 111:1-3. [PMID: 24275206 DOI: 10.1016/j.ymgme.2013.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 11/05/2013] [Indexed: 11/24/2022]
Affiliation(s)
- Olivier Braissant
- Inborn Errors of Metabolism, Service of Biomedicine, Lausanne University Hospital, Avenue Pierre-Decker 2, 1011-Lausanne, Switzerland
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20
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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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