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Alhomsi D, Abdalsalam D, Sulaiman R, Bakleh S, Alasmar D. Novel guanidinoacetate methyltransferase (GAMT) mutation associated with cerebral creatine deficiency syndrome in a Syrian child: a case report. Ann Med Surg (Lond) 2023; 85:1906-1910. [PMID: 37228909 PMCID: PMC10205335 DOI: 10.1097/ms9.0000000000000385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/01/2023] [Indexed: 05/27/2023] Open
Abstract
Guanidinoacetate methyltransferase (GAMT) deficiency, also known as cerebral creatine deficiency syndrome type 2 (CCDS2), is an uncommon disease caused by an innate genetic defect in the metabolic pathway of creatine inherited in an autosomal recessive manner. It is a rare cause of neurological regression and epilepsy. In this report, we present the first GAMT deficiency case in Syria related to a novel variant. Case Presentation A 2.5-year-old boy presented to the paediatric neurology clinic with evidence of neurodevelopmental delays and intellectual disabilities. Recurrent eye blinking, generalized non-motor (absence) seizures, hyperactivity, and poor eye contact were revealed in the neurological examination. Some athetoid and dystonic movements were noticed. His electroencephalography (EEG) was very disturbed because of generalized spike-wave and slow-wave discharges. Based on these findings antiepileptic drugs were administered. His seizures slightly improved, but then relapsed with myoclonic and drop attacks. After 6 years of unbeneficial treatment, a genetic test was required. Whole-exome sequencing was conducted and identified a novel homozygous GAMT variant (NM_138924.2:c.391+5G>C). Treatment with oral creatine supplementation, ornithine, and sodium benzoate was administered. After 1.7 years of follow-up, the child was almost seizure-free with a remarkable reduction of epileptic activity on EEG. He demonstrated good-but not complete-behavioural and motor improvement due to delayed diagnosis and treatment. Conclusion GAMT deficiency should be considered in differential diagnoses in children with neurodevelopmental regression along with drug-refractory epilepsy. A special concern is needed in Syria for such genetic disorders; regarding the high prevalence of consanguinity. Whole-exome sequencing and genetic analysis can be used to diagnose this disorder. We reported a novel GAMT variant to extend its mutation spectrum and provide an additional molecular marker for the definitive diagnosis of GAMT deficiency patients and prenatal diagnosis in the affected families.
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Affiliation(s)
| | | | | | - Sameer Bakleh
- Department of Neurology, Pediatrics University Hospital
| | - Diana Alasmar
- Department of Inherited Metabolic Diseases, Pediatrics University Hospital, Damascus, Syria
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Poggio F, Brofiga M, Tedesco M, Massobrio P, Adriano E, Balestrino M. Lack of Epileptogenic Effects of the Creatine Precursor Guanidinoacetic Acid on Neuronal Cultures In Vitro. Biomolecules 2022; 13. [PMID: 36671459 DOI: 10.3390/biom13010074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/19/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
The creatine precursor Guanidinoacetic Acid (GAA) accumulates in the genetic deficiency of the GuanidinoAcetate Methyl Transferase (GAMT) enzyme and it is believed to cause the seizures that often occur in this condition. However, evidence that it is indeed epileptogenic is scarce and we previously found that it does not cause neuronal hyperexcitation in in vitro brain slices. Here, we used Micro-Electrode Arrays (MEAs) to further investigate the electrophysiological effects of its acute and chronic administration in the networks of cultured neurons, either neocortical or hippocampal. We found that: (1) GAA at the 1 µM concentration, comparable to its concentration in normal cerebrospinal fluid, does not modify any of the parameters we investigated in either neuronal type; (2) at the 10 µM concentration, very similar to that found in the GAMT deficiency, it did not affect any of the parameters we tested except the bursting rate of neocortical networks and the burst duration of hippocampal networks, both of which were decreased, a change pointing in a direction opposite to epileptogenesis; (3) at the very high and unphysiological 100 µM concentration, it caused a decrease in all parameters, a change that again goes in the direction opposite to epileptogenesis. Our results confirm that GAA is not epileptogenic.
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Bianchi M, Rossi L, Pierigè F, De Angeli P, Aliano MP, Carducci C, Di Carlo E, Pascucci T, Nardecchia F, Leuzzi V, Magnani M. Engineering new metabolic pathways in isolated cells for the degradation of guanidinoacetic acid and simultaneous production of creatine. Mol Ther Methods Clin Dev 2022; 25:26-40. [PMID: 35317049 PMCID: PMC8917272 DOI: 10.1016/j.omtm.2022.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 02/19/2022] [Indexed: 11/23/2022]
Abstract
Here we report, for the first time, the engineering of human red blood cells (RBCs) with an entire metabolic pathway as a potential strategy to treat patients with guanidinoacetate methyltransferase (GAMT) deficiency, capable of reducing the high toxic levels of guanidinoacetate acid (GAA) and restoring proper creatine levels in blood and tissues. We first produced a recombinant form of native human GAMT without any tags to encapsulate into RBCs. Due to the poor solubility and stability features of the recombinant enzyme, both bioinformatics studies and extensive optimization work were performed to select a mutant GAMT enzyme, where only four critical residues were replaced, as a lead candidate. However, GAMT-loaded RBCs were ineffective in GAA consumption and creatine production because of the limiting intra-erythrocytic S-adenosyl methionine (SAM) content unable to support GAMT activity. Therefore, a recombinant form of human methionine adenosyl transferase (MAT) was developed. RBCs co-entrapped with both GAMT and MAT enzymes performed, in vitro, as a competent cellular bioreactor to remove GAA and produce creatine, fueled by physiological concentrations of methionine and the ATP generated by glycolysis. Our results highlight that metabolic engineering of RBCs is possible and represents proof of concept for the design of novel therapeutic approaches.
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Affiliation(s)
- Marzia Bianchi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, Italy
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, Italy.,EryDel, Via Antonio Meucci 3, 20091 Bresso, Milan, Italy
| | - Francesca Pierigè
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, Italy
| | - Pietro De Angeli
- Center for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Mattia Paolo Aliano
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, Italy
| | - Claudia Carducci
- Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | - Emanuele Di Carlo
- Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | - Tiziana Pascucci
- Department of Psychology and "Daniel Bovet" Center, Sapienza University, 00184 Rome, Italy.,Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia, 00142 Rome, Italy
| | - Francesca Nardecchia
- Division of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University, 00185 Rome, Italy
| | - Vincenzo Leuzzi
- Division of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University, 00185 Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, Italy.,EryDel, Via Antonio Meucci 3, 20091 Bresso, Milan, Italy
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Rossi L, Nardecchia F, Pierigè F, Ventura R, Carducci C, Leuzzi V, Magnani M, Cabib S, Pascucci T. Intellectual Disability and Brain Creatine Deficit: Phenotyping of the Genetic Mouse Model for GAMT Deficiency. Genes (Basel) 2021; 12:1201. [PMID: 34440375 DOI: 10.3390/genes12081201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/23/2021] [Accepted: 07/25/2021] [Indexed: 11/17/2022] Open
Abstract
Guanidinoacetate methyltransferase deficiency (GAMT-D) is one of three cerebral creatine (Cr) deficiency syndromes due to pathogenic variants in the GAMT gene (19p13.3). GAMT-D is characterized by the accumulation of guanidinoacetic acid (GAA) and the depletion of Cr, which result in severe global developmental delay (and intellectual disability), movement disorder, and epilepsy. The GAMT knockout (KO) mouse model presents biochemical alterations in bodily fluids, the brain, and muscles, including increased GAA and decreased Cr and creatinine (Crn) levels, which are similar to those observed in humans. At the behavioral level, only limited and mild alterations have been reported, with a large part of analyzed behaviors being unaffected in GAMT KO as compared with wild-type mice. At the cerebral level, decreased Cr and Crn and increased GAA and other guanidine compound levels have been observed. Nevertheless, the effects of Cr deficiency and GAA accumulation on many neurochemical, morphological, and molecular processes have not yet been explored. In this review, we summarize data regarding behavioral and cerebral GAMT KO phenotypes, and focus on uncharted behavioral alterations that are comparable with the clinical symptoms reported in GAMT-D patients, including intellectual disability, poor speech, and autistic-like behaviors, as well as unexplored Cr-induced cerebral alterations.
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Rostami P, Hosseinpour S, Ashrafi MR, Alizadeh H, Garshasbi M, Tavasoli AR. Primary creatine deficiency syndrome as a potential missed diagnosis in children with psychomotor delay and seizure: case presentation with two novel variants and literature review. Acta Neurol Belg 2020; 120:511-516. [PMID: 31222513 DOI: 10.1007/s13760-019-01168-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 06/06/2019] [Indexed: 11/24/2022]
Abstract
Creatine is the main source of energy for the brain. Primary creatine deficiency syndromes (PCDSs) are inborn error of metabolism of creatine synthesis. Symptoms of central nervous system involvement are the most common clinical manifestations in these disorders. We reviewed medical records of all genetically confirmed patients diagnosed by whole exome sequencing who were referred to Myelin and Neurodegenerative Disorders Clinic, Children's Medical Center, Tehran, Iran, from May 2016 to Dec 2018. A literature review was conducted on clinical and genomic variability of PCDS to compare our patients with previously reported cases. We report two patients with creatine deficiency among a cohort of 550 registered cases out of which 200 patients had a genetically confirmed neurodegenerative disorder diagnosis. The main complain in the first patient with creatine transporter (CRTR) deficiency was seizure and genetic study in this patient identified a novel hemizygote variant of "c.92 > T; p.Pro31Leu" in the first exon of SLC6A8 gene. The second patient with guanidinoacetate methyltransferase (GAMT) deficiency had an unknown motor and speech delay as the striking manifestation and molecular assay revealed a novel homozygote variant of "c.134G > A; p.Trp45*" in the first exon of GAMT gene. PCDSs usually are associated with nonspecific neurologic symptoms. The first presented case had a mean delayed diagnosis of 5 years. Therefore, in children with unexplained neurologic features including developmental delay and/or regression, mental disability and repeated seizures without any significant findings in metabolic studies, PCDSs can be considered as a differential diagnosis and molecular analysis can be helpful for the precise diagnosis and treatment.
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Affiliation(s)
- Parastoo Rostami
- Division of Pediatric Endocrinology and Metabolism, Growth and Development Research Center, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Sareh Hosseinpour
- Myelin Disorders Clinic (Iranian Neurometabolic Registry), Pediatric Neurology Division, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Myelin Disorders Clinic (Iranian Neurometabolic Registry), Pediatric Neurology Division, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Houman Alizadeh
- Division of Pediatric Radiology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Teheran, Iran.
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic (Iranian Neurometabolic Registry), Pediatric Neurology Division, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
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Khaikin Y, Sidky S, Abdenur J, Anastasi A, Ballhausen D, Buoni S, Chan A, Cheillan D, Dorison N, Goldenberg A, Goldstein J, Hofstede FC, Jacquemont ML, Koeberl DD, Lion-Francois L, Lund AM, Mention K, Mundy H, O'Rourke D, Pitelet G, Raspall-Chaure M, Tassini M, Billette de Villemeur T, Williams M, Salomons GS, Mercimek-Andrews S. Treatment outcome of twenty-two patients with guanidinoacetate methyltransferase deficiency: An international retrospective cohort study. Eur J Paediatr Neurol 2018; 22:369-79. [PMID: 29506905 DOI: 10.1016/j.ejpn.2018.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 01/23/2018] [Accepted: 02/12/2018] [Indexed: 11/23/2022]
Abstract
PURPOSE Guanidinoacetate methyltransferase (GAMT) deficiency is an autosomal recessive disorder caused by pathogenic variants in GAMT. Brain creatine depletion and guanidinoacetate accumulation cause developmental delay, seizures and movement disorder. Treatment consists of creatine, ornithine and arginine-restricted diet. We initiated an international treatment registry using Research Electronic Data Capture (REDCap) software to evaluate treatment outcome. METHODS Physicians completed an online REDCap questionnaire. Clinical severity score applied pre-treatment and on treatment. RESULTS There were 22 patients. All had developmental delay, 18 had seizures and 8 had movement disorder. Based on the clinical severity score, 5 patients had a severe, 14 patients had a moderate and 3 patients had a mild phenotype. All patients had pathogenic variants in GAMT. The phenotype ranged from mild to moderate in patients with the most common c.327G > A variant. The phenotype ranged from mild to severe in patients with truncating variants. All patients were on creatine, 18 patients were on ornithine and 15 patients were on arginine- or protein-restricted diet. Clinical severity score improved in 13 patients on treatment. Developmental delay improved in five patients. One patient achieved normal development. Eleven patients became seizure free. Movement disorder resolved in four patients. CONCLUSION In our small patient cohort, there seems to be no phenotype-genotype correlation. Creatine and ornithine and/or arginine- or protein-restricted diet were the most useful treatment to improve phenotype.
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Sun W, Wang Y, Zu Z, Jiang Y, Lu W, Wang H, Wu B, Zhang P, Peng X, Zhou H. First reported Chinese case of guanidinoacetate methyltransferase deficiency in a 4-year-old child. Clin Chim Acta 2017; 470:42-45. [PMID: 28438604 DOI: 10.1016/j.cca.2017.04.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 04/14/2017] [Accepted: 04/15/2017] [Indexed: 11/17/2022]
Abstract
Guanidinoacetate methyltransferase (GAMT) deficiency is a rare inherited disorder characterized by creatine (Cr) depletion and guanidinoacetate (GAA) accumulation in body fluids. We report the first identified Chinese case, diagnosed in a 4-year-old girl with onset of global developmental. Low Cr and high GAA levels were detected in her serum and urine, and low Cr level in her brain. Compound heterozygous variants in GAMT gene were found, including a previously reported variant at c.491dupG which was inherited from her mother and a novel variant at c.564G>T, which was inherited from her father. The Cr and GAA levels returned back to normal after 3 months of treatment. After one year of treatment, the patient stopped taking antiepileptic drugs and her electroencephalogram (EEG) was also back to normal. The girl was followed up for five years and exhibited good results beyond our expectation. The results have shown that protein restriction with high-dose ornithine and creatine supplements have strong therapeutic potential for our patient.
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Affiliation(s)
- Weihua Sun
- Pediatrics Research Institute, Children's Hospital of Fudan University, Shanghai, China
| | - Yi Wang
- Department of Neurology, Children's Hospital of Fudan University, Research Institute of Brain Science, Shanghai, China.
| | - Zhen Zu
- Department of Radiology, Children's Hospital of Shanghai, China
| | - Yi Jiang
- Division of Biochemical Genetics, Baylor Genetics, Houston, TX, USA
| | - Wei Lu
- Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Huijun Wang
- Pediatrics Research Institute, Children's Hospital of Fudan University, Shanghai, China
| | - Bingbing Wu
- Pediatrics Research Institute, Children's Hospital of Fudan University, Shanghai, China
| | - Ping Zhang
- Pediatrics Research Institute, Children's Hospital of Fudan University, Shanghai, China
| | - Xiaomin Peng
- Pediatrics Research Institute, Children's Hospital of Fudan University, Shanghai, China
| | - Hao Zhou
- Department of Neurology, Children's Hospital of Fudan University, Research Institute of Brain Science, Shanghai, China
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Pacheva I, Ivanov I, Penkov M, Kancheva D, Jordanova A, Ivanova M. Creatine Deficiency Syndrome could be Missed Easily: A Case Report of Guanidinoacetate Methyltransferase Deficiency Presented with Neurodevelopmental Delay, Seizures, and Behavioral Changes, but Normal Structural MRI. Ann Clin Lab Sci 2016; 46:557-561. [PMID: 27650626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A case with GAMT deficiency (homozygous c.64dupG mutation) presented with neurodevelopmental delay, rare seizures, behavioral disturbances, and mild hypotonia, posing diagnostic challenges. Metabolic investigations showed low creatinine in plasma and urine (guanidinoacetate couldn't be investigated) and slightly elevated lactate. MRI was normal. Correct diagnosis was possible only after MR spectroscopy was performed at age 5½ years. A homozygous c.64dupG mutation of the GAMT gene was identified in the proband. In conclusion, every case with neurodevelopmental delay or arrest, especially when accompanied by seizures, behavioral impairment, muscle hypotonia or extrapyramidal symptoms should undergo MRI with MR spectroscopy. Normal structural MRI doesn't exclude a creatine deficiency syndrome. Biochemical investigations of guanidinoacetate, creatine, and creatinine in body fluid should be done to diagnose cerebral creatine deficiency syndromes and to specify the deficient enzyme. Thus, a treatable disease will not be missed.
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Affiliation(s)
- Iliyana Pacheva
- Department of Pediatrics and Medical Genetics, Medical University - Plovdiv, Sofia, Bulgaria
| | - Ivan Ivanov
- Department of Pediatrics and Medical Genetics, Medical University - Plovdiv, Sofia, Bulgaria
| | - Marin Penkov
- Department of Imaging Diagnosis, University Hospital "St. Ivan Rilski" Sofia, Sofia, Bulgaria
| | - Daliya Kancheva
- Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerpen, Holland; Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Sofia, Bulgaria
| | - Albena Jordanova
- Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerpen, Holland; Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Sofia, Bulgaria
| | - Mariya Ivanova
- National Genetic Laboratory, University Hospital of Obstetrics and Gynecology, Sofia; Department of Analytical Chemistry, Sofia University "St. Kl. Ohridsky", Sofia, Bulgaria
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Mercimek-Mahmutoglu S, Pop A, Kanhai W, Fernandez Ojeda M, Holwerda U, Smith D, Loeber JG, Schielen PCJI, Salomons GS. A pilot study to estimate incidence of guanidinoacetate methyltransferase deficiency in newborns by direct sequencing of the GAMT gene. Gene 2015; 575:127-31. [PMID: 26319512 DOI: 10.1016/j.gene.2015.08.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 08/21/2015] [Accepted: 08/23/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND GAMT deficiency is an autosomal recessive disorder of creatine biosynthesis causing developmental delays or intellectual disability in untreated patients as a result of irreversible brain damage occurring prior to diagnosis. Normal neurodevelopmental outcome has been reported in patients treated from neonatal period highlighting the importance of early treatment. METHODS Five hundred anonymized newborns from the National Newborn Screening Program of The Netherlands were included into this pilot study. Direct sequencing of the coding region of the GAMT gene was applied following DNA extraction. The disease causing nature of novel missense variants in the GAMT gene was studied by overexpression studies. GAA and creatine was measured in blood dot spots. RESULTS We detected two carriers, one with a known common (c.327G>A) and one with a novel mutation (c.297_309dup (p.Arg105Glyfs*) in the GAMT gene. The estimated incidence of GAMT deficiency was 1:250,000. We also detected five novel missense variants. Overexpression of these variants in GAMT deficient fibroblasts did restore GAMT activity and thus all were considered rare, but not disease causing variants including the c.131G>T (p.Arg44Leu) variant. Interestingly, this variant was predicted to be pathogenic by in silico analysis. The variants were included in the Leiden Open Variation Database (LOVD) database (www.LOVD.nl/GAMT). The average GAA level was 1.14μmol/L±0.45 standard deviations. The average creatine level was 408μmol/L±106. The average GAA/creatine ratio was 2.94±0.136. CONCLUSION The estimated incidence of GAMT deficiency is 1:250,000 newborns based on our pilot study. The newborn screening for GAMT deficiency should be implemented to identify patients at the asymptomatic stage to achieve normal neurodevelopmental outcome for this treatable neurometabolic disease. Biochemical investigations including GAA, creatine and GAMT enzyme activity measurements are essential to confirm the diagnosis of GAMT deficiency. According to availability, all missense variants can be assessed functionally, as in silico prediction analysis of missense variants is not sufficient to confirm the pathogenicity of missense variants.
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Affiliation(s)
- S Mercimek-Mahmutoglu
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Canada; Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada.
| | - A Pop
- Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Neurosciences Campus, Amsterdam, The Netherlands
| | - W Kanhai
- Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Neurosciences Campus, Amsterdam, The Netherlands
| | - M Fernandez Ojeda
- Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Neurosciences Campus, Amsterdam, The Netherlands
| | - U Holwerda
- Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Neurosciences Campus, Amsterdam, The Netherlands
| | - D Smith
- Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Neurosciences Campus, Amsterdam, The Netherlands
| | - J G Loeber
- National Institute for Public Health and the Environment, Centre for Infectious Diseases Research, and Screening, Bilthoven, The Netherlands
| | - P C J I Schielen
- National Institute for Public Health and the Environment, Centre for Infectious Diseases Research, and Screening, Bilthoven, The Netherlands
| | - G S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Neurosciences Campus, Amsterdam, The Netherlands.
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Mercimek-Mahmutoglu S, Salomons GS, Chan A. Case study for the evaluation of current treatment recommendations of guanidinoacetate methyltransferase deficiency: ineffectiveness of sodium benzoate. Pediatr Neurol 2014; 51:133-7. [PMID: 24766785 DOI: 10.1016/j.pediatrneurol.2014.02.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/01/2014] [Accepted: 02/13/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Guanidinoacetate methyltransferase deficiency is an autosomal recessively inherited disorder of creatine biosynthesis. We report a new patient with guanidinoacetate methyltransferase deficiency and her >3-year treatment outcome. PATIENT This is a 6-year-old girl who was diagnosed with guanidinoacetate methyltransferase deficiency at the age of 28 months. She presented with moderate global developmental delay, one afebrile seizure, and hypotonia between 6 and 18 months of life. She was treated with creatine and ornithine supplementation and a strict arginine-restricted diet for 42 months. RESULTS Mutation analysis (compound heterozygous mutations, a known c.327G>A and a novel c.58dupT [p.Trp20LeufsX65]) and enzyme studies in primary fibroblasts confirmed the diagnosis. After 33 months of therapy, her cerebrospinal fluid guanidinoacetate level decreased from 47 to 5.3 times the normal level. Brain creatine by proton magnetic resonance spectroscopy increased by >75% but did not normalize in the basal ganglia and white matter after 3 years of therapy. Additional treatment with sodium benzoate for 17 months did not further improve plasma guanidinoacetate levels, which questions the relevance of this therapy. CONCLUSION Treatment did not improve moderate intellectual disability or normalize guanidinoacetate accumulation in the central nervous system.
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Affiliation(s)
- Saadet Mercimek-Mahmutoglu
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Gajja S Salomons
- Metabolic Laboratory, Department of Clinical Chemistry, VU University Medical Centre, Amsterdam, The Netherlands
| | - Alicia Chan
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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Viau KS, Ernst SL, Pasquali M, Botto LD, Hedlund G, Longo N. Evidence-based treatment of guanidinoacetate methyltransferase (GAMT) deficiency. Mol Genet Metab 2013; 110:255-62. [PMID: 24071436 DOI: 10.1016/j.ymgme.2013.08.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/30/2013] [Accepted: 08/31/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Guanidinoacetate methyltransferase (GAMT) deficiency causes cerebral creatine deficiency. Patients can have autistic behavior, seizures, intellectual disability, and severe speech delay. The goal of therapy is to increase creatine while reducing potentially neurotoxic guanidinoacetate concentrations. Here we evaluate how different therapies affect plasma guanidinoacetate levels in patients with GAMT deficiency. METHODS Retrospective analysis of data from five new patients with GAMT deficiency (four with delays and seizures, one diagnosed at birth). RESULTS The four symptomatic patients had decreased brain creatine by magnetic resonance spectroscopy and three also had abnormal globi pallidi by MRI. GAMT sequencing identified four previously reported mutations and one novel missense mutation (c.233T>A/p.V78E). Treatment with creatine (250-1000 mg/kg/day), ornithine (100-800 mg/kg/day), and sodium benzoate (50-135 mg/kg/day) supplements along with dietary protein restriction (0.8-1.5 g/kg/day) improved seizures and development with all patients becoming verbal. The patient treated at birth remains developmentally normal. Reduction in glycine and increase in ornithine levels significantly decreased plasma guanidinoacetate, with glycine levels being the best predictor of guanidinoacetate levels. In contrast, arginine levels were not significantly correlated with plasma guanidinoacetate. CONCLUSIONS Our results show that supplements of creatine, sodium benzoate (to reduce glycine) and ornithine reduce guanidinoacetate levels in patients with GAMT deficiency (dietary therapy was not evaluated in our study). Normal development with early therapy renders GAMT deficiency an ideal candidate for inclusion in newborn screening panels.
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Affiliation(s)
- Krista S Viau
- Department of Pediatrics, Division of Medical Genetics, University of Utah, 50 North Mario Capecchi Drive, 2C412 SOM, Salt Lake City, UT 84132, USA.
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