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Mason E, Hindmarch CCT, Dunham‐Snary KJ. Medium-chain Acyl-COA dehydrogenase deficiency: Pathogenesis, diagnosis, and treatment. Endocrinol Diabetes Metab 2022; 6:e385. [PMID: 36300606 PMCID: PMC9836253 DOI: 10.1002/edm2.385] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/09/2022] [Accepted: 10/01/2022] [Indexed: 11/06/2022] Open
Abstract
INTRODUCTION Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD) is the most common inherited metabolic disorder of β-oxidation. Patients with MCADD present with hypoketotic hypoglycemia, which may quickly progress to lethargy, coma, and death. Prognosis for MCADD patients is highly promising once a diagnosis has been established, though management strategies may vary depending on the severity of illness and the presence of comorbidities. METHODS AND RESULTS Given the rapid developments in the world of gene therapy and implementation of newborn screening for inherited metabolic disorders, the provision of concise and contemporary knowledge of MCADD is essential for clinicians to effectively manage patients. Thus, this review aims to consolidate current information for physicians on the pathogenesis, diagnostic tools, and treatment options for MCADD patients. CONCLUSION MCADD is a commonly inherited metabolic disease with serious implications for health outcomes, particularly in children, that may be successfully managed with proper intervention.
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Affiliation(s)
- Emily Mason
- Department of Biomedical and Molecular SciencesQueen's UniversityKingstonOntarioCanada
| | | | - Kimberly J. Dunham‐Snary
- Department of Biomedical and Molecular SciencesQueen's UniversityKingstonOntarioCanada,Department of MedicineQueen's UniversityKingstonOntarioCanada
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Potter BK, Hutton B, Clifford TJ, Pallone N, Smith M, Stockler S, Chakraborty P, Barbeau P, Garritty CM, Pugliese M, Rahman A, Skidmore B, Tessier L, Tingley K, Coyle D, Greenberg CR, Korngut L, MacKenzie A, Mitchell JJ, Nicholls S, Offringa M, Schulze A, Taljaard M. Establishing core outcome sets for phenylketonuria (PKU) and medium-chain Acyl-CoA dehydrogenase (MCAD) deficiency in children: study protocol for systematic reviews and Delphi surveys. Trials 2017; 18:603. [PMID: 29258568 PMCID: PMC5735866 DOI: 10.1186/s13063-017-2327-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/13/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Inherited metabolic diseases (IMD) are a large group of rare single-gene disorders that are typically diagnosed early in life. There are important evidence gaps related to the comparative effectiveness of therapies for IMD, which are in part due to challenges in conducting randomized controlled trials (RCTs) for rare diseases. Registry-based RCTs present a unique opportunity to address these challenges provided the registries implement standardized collection of outcomes that are important to patients and their caregivers and to clinical providers and healthcare systems. Currently there is no core outcome set (COS) for studies evaluating interventions for paediatric IMD. This protocol outlines a study that will establish COS for each of two relatively common IMD in children, phenylketonuria (PKU) and medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. METHODS This two-part study is registered with the Core Outcome Measures in Effectiveness Trials (COMET) initiative. Part 1 includes a rapid review and development of an evidence map to identify a comprehensive listing of outcomes reported in past studies of PKU and MCAD deficiency. The review follows established methods for knowledge synthesis, including a comprehensive search strategy, two stages of screening citations against inclusion/exclusion criteria by two reviewers working independently, and extraction of important data elements from eligible studies, including details of the outcomes collected and outcome measurement instruments. The review findings will inform part 2 of our study, a set of Delphi surveys to establish consensus on the highest priority outcomes for each condition. Healthcare providers, families of children with PKU or MCAD deficiency, and health system decision-makers will be invited to participate in two to three rounds of Delphi surveys. The design of the surveys will involve parents of children with IMD who are part of a family advisory forum. DISCUSSION This protocol is a crucial step in developing the capacity to launch RCTs with meaningful outcomes that address comparative effectiveness questions in the field of paediatric IMD. Such trials will contribute high-quality evidence to inform decision-making by patients and their family members, clinicians, and policy-makers.
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Affiliation(s)
- Beth K. Potter
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | - Brian Hutton
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - Tammy J. Clifford
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Canadian Agency for Drugs and Technologies in Health, Ottawa, ON Canada
| | - Nicole Pallone
- Patient/family partner and Canadian PKU & Allied Disorders Inc, Sparwood, BC Canada
| | - Maureen Smith
- Patient/family partner and Canadian Organization for Rare Disorders, Ottawa, ON Canada
| | - Sylvia Stockler
- BC Children’s Hospital and University of British Columbia, Vancouver, BC Canada
| | - Pranesh Chakraborty
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
| | | | | | - Michael Pugliese
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | - Alvi Rahman
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | | | - Laure Tessier
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
| | - Kylie Tingley
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | - Doug Coyle
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | | | - Lawrence Korngut
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada
| | - Alex MacKenzie
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
| | | | - Stuart Nicholls
- Clinical Research Unit, Children’s Hospital of Eastern Ontario, Ottawa, ON Canada
- Ontario Child Health SUPPORT Unit (OCHSU), Ottawa, ON Canada
| | - Martin Offringa
- Hospital for Sick Children and University of Toronto, Toronto, ON Canada
| | - Andreas Schulze
- Hospital for Sick Children and University of Toronto, Toronto, ON Canada
| | - Monica Taljaard
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - In collaboration with the Canadian Inherited Metabolic Diseases Research Network
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Ottawa Hospital Research Institute, Ottawa, ON Canada
- Canadian Agency for Drugs and Technologies in Health, Ottawa, ON Canada
- Patient/family partner and Canadian PKU & Allied Disorders Inc, Sparwood, BC Canada
- Patient/family partner and Canadian Organization for Rare Disorders, Ottawa, ON Canada
- BC Children’s Hospital and University of British Columbia, Vancouver, BC Canada
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
- University of Manitoba, Winnipeg, MB Canada
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada
- McGill University Health Centre, Montreal, QC Canada
- Clinical Research Unit, Children’s Hospital of Eastern Ontario, Ottawa, ON Canada
- Ontario Child Health SUPPORT Unit (OCHSU), Ottawa, ON Canada
- Hospital for Sick Children and University of Toronto, Toronto, ON Canada
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Huidekoper HH, Ackermans MT, Koopman R, van Loon LJC, Sauerwein HP, Wijburg FA. Normal rates of whole-body fat oxidation and gluconeogenesis after overnight fasting and moderate-intensity exercise in patients with medium-chain acyl-CoA dehydrogenase deficiency. J Inherit Metab Dis 2013; 36:831-40. [PMID: 22976767 DOI: 10.1007/s10545-012-9532-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/10/2012] [Accepted: 07/30/2012] [Indexed: 01/21/2023]
Abstract
BACKGROUND Impairments in gluconeogenesis have been implicated in the pathophysiology of fasting hypoglycemia in medium-chain acyl-CoA dehydrogenase deficiency. However, whole body glucose and fat metabolism have never been studied in vivo. METHODS Stable isotope methodology was applied to compare fat and glucose metabolism between four adult patients with MCADD and four matched controls both at rest and during 1.5 h of moderate-intensity exercise. Additionally, intramyocellular lipid and glycogen content and intramyocellular acylcarnitines were assessed in muscle biopsies collected prior to and immediately after cessation of exercise. RESULTS At rest, plasma FFA turnover was significantly higher in patients with MCADD, whereas the plasma FFA concentrations did not differ between patients and controls. Blood glucose kinetics did not differ between groups both at rest and during exercise. Palmitate and FFA turnover, total fat and carbohydrate oxidation rates, the use of muscle glycogen and muscle derived triglycerides during exercise did not differ between patients and controls. Plasma FFA oxidation rates were significantly lower in patients at the latter stages of exercise. Free carnitine levels in muscle were lower in patients, whereas no differences were detected in muscle acetylcarnitine levels. CONCLUSIONS Whole-body or skeletal muscle glucose and fat metabolism were not impaired in adult patients with MCADD. This implies that MCADD is not rate limiting for energy production under the conditions studied. In addition, patients with MCADD have a higher FFA turnover rate after overnight fasting, which may stimulate ectopic lipid deposition and, as such, make them more susceptible for developing insulin resistance.
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Affiliation(s)
- Hidde H Huidekoper
- Department of Pediatrics, University of Amsterdam, Amsterdam, The Netherlands
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4
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Madsen KL, Preisler N, Orngreen MC, Andersen SP, Olesen JH, Lund AM, Vissing J. Patients with medium-chain acyl-coenzyme a dehydrogenase deficiency have impaired oxidation of fat during exercise but no effect of L-carnitine supplementation. J Clin Endocrinol Metab 2013; 98:1667-75. [PMID: 23426616 DOI: 10.1210/jc.2012-3791] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND It is not clear to what extent skeletal muscle is affected in patients with medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD). l-Carnitine is commonly used as a supplement in patients with MCADD, although its beneficial effect has not been verified. DESIGN We investigated (1) fuel utilization during prolonged low-intensity exercise in patients with MCADD and (2) the influence of 4 weeks of oral l-carnitine supplementation on fuel utilization during exercise. METHODS Four asymptomatic patients with MCADD and 11 untrained, healthy, age- and sex-matched control subjects were included. The subjects performed a 1-hour cycling test at a constant workload corresponding to 55% of Vo2max, while fat and carbohydrate metabolism was assessed, using the stable isotope technique and indirect calorimetry. The patients ingested 100 mg/kg/d of l-carnitine for 4 weeks, after which the cycling tests were repeated. RESULTS At rest, palmitate oxidation and total fatty acid oxidation (FAO) rates were similar in patients and healthy control subjects. During constant workload cycling, palmitate oxidation and FAO rates increased in both groups, but increased 2 times as much in healthy control subjects as in patients (P = .007). Palmitate oxidation and FAO rates were unchanged by the l-carnitine supplementation. CONCLUSION Our results indicate that patients with MCADD have an impaired ability to increase FAO during exercise but less so than that observed in patients with a number of other disorders of fat oxidation, which explains the milder skeletal muscle phenotype in MCADD. The use of carnitine supplementation in MCADD cannot be supported by the present findings.
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Affiliation(s)
- K L Madsen
- Neuromuscular Research Unit, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
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5
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Prasad C, Speechley KN, Dyack S, Rupar CA, Chakraborty P, Kronick JB. Incidence of medium-chain acyl-CoA dehydrogenase deficiency in Canada using the Canadian Paediatric Surveillance Program: Role of newborn screening. Paediatr Child Health 2012; 17:185-9. [PMID: 23543005 PMCID: PMC3381659 DOI: 10.1093/pch/17.4.185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2011] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The incidence of medium-chain acyl-CoA dehydrogenase deficiency (MCADD) was estimated using the Canadian Paediatric Surveillance Program (CPSP) in Canada over a three-year period. Data regarding mutations associated with MCADD cases were collected wherever available. METHODS Data were collected over a 36-month period using a monthly mailed questionnaire distributed through the CPSP to more than 2500 Canadian paediatricians, medical geneticists and paediatric pathologists. RESULTS AND CONCLUSIONS During the three years of MCADD surveillance, 46 confirmed cases out of a total of 71 reported cases were found - an average of approximately 15 cases per year. This rate is lower than the initial estimate of approximately 30 cases per year of MCADD in Canada, based on the reported incidence of MCADD in the literature of approximately one in 10,000 to one in 20,000. All cases ascertained by newborn screening were asymptomatic. There were two deaths, both in jurisdictions without newborn screening for MCADD. The data support population-based newborn screening for MCADD.
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Affiliation(s)
- Chitra Prasad
- Department of Paediatrics
- Children’s Health Research Institute
| | - Kathy N Speechley
- Department of Paediatrics
- Children’s Health Research Institute
- Department of Epidemiology & Biostatistics, The University of Western Ontario, London, Ontario
| | - Sarah Dyack
- Department of Paediatrics, Dalhousie University, Halifax, Nova Scotia
| | - Charles A Rupar
- Department of Paediatrics
- Children’s Health Research Institute
- Biochemistry, The University of Western Ontario, London
| | - Pranesh Chakraborty
- Newborn Screening Ontario, Children’s Hospital of Eastern Ontario
- Department of Paediatrics, University of Ottawa, Ottawa
| | - Jonathan B Kronick
- Department of Paediatrics, Dalhousie University, Halifax, Nova Scotia
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario
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Nasser M, Javaheri H, Fedorowicz Z, Noorani Z. Carnitine supplementation for inborn errors of metabolism. Cochrane Database Syst Rev 2012; 2012:CD006659. [PMID: 22336821 PMCID: PMC7390060 DOI: 10.1002/14651858.cd006659.pub3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Inborn errors of metabolism are genetic conditions which can lead to abnormalities in the synthesis and metabolism of proteins, carbohydrates, or fats. It has been proposed that in some instances carnitine supplementation should be provided to infants with a suspected metabolic disease as an interim measure, particularly whilst awaiting test results. Carnitine supplementation is used in the treatment of primary carnitine deficiency, and also where the deficiency is a secondary complication of several inborn errors of metabolism, such as organic acidaemias and fatty acid oxidation defects in children and adults. OBJECTIVES To assess the effectiveness and safety of carnitine supplementation in the treatment of inborn errors of metabolism. SEARCH METHODS We searched the Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register, the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 4) and MEDLINE via Ovid (1950 to July week 4 2007), LILACS (15/05/2008) and Iranmedex (15/05/2008) and also the reference lists of retrieved articles.Date of most recent search of the Group's Inborn Errors of Metabolism Register: 27 October 2011. SELECTION CRITERIA Randomised controlled trials and quasi-randomised controlled trials comparing carnitine supplementation (in different dose, frequency, or duration) versus placebo in children and adults diagnosed with an inborn error of metabolism. DATA COLLECTION AND ANALYSIS Two authors independently screened and assessed the eligibility of the identified trials. MAIN RESULTS No trials were included in the review. AUTHORS' CONCLUSIONS There are no published or ongoing randomised controlled clinical trials relevant to this review question. Therefore, in the absence of any high level evidence, clinicians should base their decisions on clinical experience and in conjunction with preferences of the individual where appropriate. This does not mean that carnitine is ineffective or should not be used in any inborn error of metabolism. However, given the lack of evidence both on the effectiveness and safety of carnitine and on the necessary dose and frequency to be prescribed, the current prescribing practice should continue to be observed and monitored with care until further evidence is available. Methodologically sound trials, reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement, are required. It should be considered whether placebo-controlled trials in potentially lethal diseases, e.g. carnitine transporter disorder or glutaric aciduria type I, are ethical.
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Affiliation(s)
- Mona Nasser
- Peninsula Dental School, University of Plymouth, Plymouth,
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Svalbe B, Zvejniece L, Vavers E, Pugovics O, Muceniece R, Liepinsh E, Dambrova M. Mildronate treatment improves functional recovery following middle cerebral artery occlusion in rats. Behav Brain Res 2011; 222:26-32. [PMID: 21420440 DOI: 10.1016/j.bbr.2011.03.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/10/2011] [Accepted: 03/11/2011] [Indexed: 11/18/2022]
Abstract
Mildronate (3-(2,2,2-trimethylhydrazinium) propionate) is an inhibitor of l-carnitine biosynthesis and an anti-ischemic drug. In the present study, we investigated the effects of mildronate in rats following focal cerebral ischemia. Male Wistar rats were subjected to transient occlusion of the middle cerebral artery (MCAO) for 90min, followed by the intraperitoneal administration of mildronate at doses of 100 and 200mg/kg 2h after reperfusion and then daily for an additional 14days. The beam-walking, rota-rod and cylinder tests were used to assess sensorimotor function, and vibrissae-evoked forelimb-placing and limb-placing tests examined responses to tactile and proprioceptive stimulation. Following behavioural testing, the infarct volume was measured. The cerebellar concentrations of l-carnitine, γ-butyrobetaine (GBB) and mildronate were also measured. The results showed that saline-treated MCAO rats had minor or no spontaneous recovery in sensorimotor and proprioceptive function up to 14days post-stroke. Treatment with mildronate at a dose of 200mg/kg was found to accelerate recovery of motor and proprioceptive deficits in limb-placing, cylinder and beam-walking tests. Analysis of rat cerebellar tissue extracts revealed that l-carnitine and GBB concentrations changed with mildronate treatment; the concentration of l-carnitine was significantly decreased by mildronate treatment, whereas the concentration of GBB was significantly increased. Cerebellar concentrations of mildronate also increased in a dose-dependent manner following systemic administration. Infarct size did not differ among the experimental groups on post-stroke day 14. The present study suggests that mildronate treatment improves the functional outcome in MCAO rats without influencing infarct size.
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Affiliation(s)
- Baiba Svalbe
- Latvian Institute of Organic Synthesis, Riga, Latvia; University of Latvia, Riga, Latvia.
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Soeters MR, Huidekoper HH, Duran M, Ackermans MT, Endert E, Fliers E, Wijburg FA, Wanders RJ, Sauerwein HP, Serlie MJ. Extended metabolic evaluation of suspected symptomatic hypoglycemia: the prolonged fast and beyond. Metabolism 2010; 59:1543-50. [PMID: 20189609 DOI: 10.1016/j.metabol.2010.01.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 01/11/2010] [Accepted: 01/27/2010] [Indexed: 11/21/2022]
Abstract
The diagnostic evaluation of spontaneous hypoglycemia in adults is mainly directed at detecting an insulinoma. Its interpretation is troublesome in those patients who develop low venous plasma glucose levels with appropriate hypoinsulinemia during a prolonged supervised fast. In this study, we investigated in this group of patients whether abnormalities in intermediary metabolism (fatty acid oxidation and amino/organic acids) could be detected that might explain the hypoinsulinemic hypoglycemia. Ten patients with otherwise unexplained low venous plasma glucose levels (<3 mmol/L) during prolonged fasting were included in the study. The patients participated in an extended metabolic protocol based on stable isotope techniques after an overnight fast to explore abnormalities in endogenous glucose production and intermediary metabolism. Endogenous glucose production, glucoregulatory hormones, plasma acylcarnitines, gluconeogenic amino acids, and rates of fatty acid and carbohydrate oxidation after 16 and 22 hours of fasting were measured. Although during the prolonged fast all patients had low venous plasma glucose level, there were no hypoglycemic events during the extended metabolic protocol. No abnormalities in endogenous glucose production (compared with reference values obtained in young healthy volunteers), fatty acid oxidation, or amino acid/organic acids were found in this patient group. In a group of patients exhibiting low venous plasma glucose levels during prolonged fasting in whom insulinoma was excluded, we found no signs of metabolic disorders. Therefore, the observation of low plasma glucose values in this subgroup of patients probably does not warrant extensive metabolic evaluation.
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Affiliation(s)
- Maarten R Soeters
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Spiekerkoetter U, Bastin J, Gillingham M, Morris A, Wijburg F, Wilcken B. Current issues regarding treatment of mitochondrial fatty acid oxidation disorders. J Inherit Metab Dis 2010; 33:555-61. [PMID: 20830526 DOI: 10.1007/s10545-010-9188-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 07/27/2010] [Accepted: 08/06/2010] [Indexed: 12/13/2022]
Abstract
Treatment recommendations in mitochondrial fatty acid oxidation (FAO) defects are diverse. With implementation of newborn screening and identification of asymptomatic patients, it is necessary to define whom to treat and how strictly. We here discuss critical questions that are currently under debate. For some asymptomatic long-chain defects, long-chain fat restriction plays a minor role, and a normal diet may be introduced. For patients presenting only with myopathic symptoms, e.g., during exercise, treatment may be adapted to energy demand. As a consequence, patients with exercise-induced myopathy may be able to return to normal activity when provided with medium-chain triglycerides (MCT) prior to exercise. There is no need to limit participation in sports. Progression of retinopathy in disorders of the mitochondrial trifunctional protein complex is closely associated with hydroxyacylcarnitine accumulation. A strict low-fat diet with MCT supplementation is recommended to slow or prevent progression of chorioretinopathy. Additional docosahexanoic acid does not prevent the decline in retinal function but does promote nonspecific improvement in visual acuity and is recommended. There is no evidence that L-carnitine supplementation is beneficial. Thus, supplementation with L-carnitine in a newborn identified by screening with either a medium-chain or long-chain defect is not supported. With respect to the use of the odd-chain medium-chain triglyceride triheptanoin in myopathic phenotypes, randomized trials are needed to establish whether triheptanoin is more effective than even-chain MCT. With increasing pathophysiological knowledge, new treatment options have been identified and are being clinically evaluated. These include the use of bezafibrates in myopathic long-chain defects.
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Affiliation(s)
- Ute Spiekerkoetter
- Department of General Pediatrics, University Children's Hospital, Duesseldorf, Germany.
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11
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Abstract
BACKGROUND Inborn errors of metabolism are genetic conditions which can lead to abnormalities in the synthesis and metabolism of proteins, carbohydrates, or fats. It has been proposed that in some instances carnitine supplementation should be provided to infants with a suspected metabolic disease as an interim measure, particularly whilst awaiting test results. Carnitine supplementation is used in the treatment of primary carnitine deficiency, and also where the deficiency is a secondary complication of several inborn errors of metabolism, such as organic acidaemias and fatty acid oxidation defects in children and adults. OBJECTIVES To assess the effectiveness and safety of carnitine supplementation in the treatment of inborn errors of metabolism. SEARCH STRATEGY We searched the Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register, the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 4) and MEDLINE via Ovid (1950 to July week 4 2007), LILACS (15/05/2008) and Iranmedex (15/05/2008) and also the reference lists of retrieved articles.Date of most recent search of the Group's Inborn Errors of Metabolism Register: 27 October 2008. SELECTION CRITERIA Randomised controlled trials and quasi-randomised controlled trials comparing carnitine supplementation (in different dose, frequency, or duration) versus placebo in children and adults diagnosed with an inborn error of metabolism. DATA COLLECTION AND ANALYSIS Two authors independently screened and assessed the eligibility of the identified trials. MAIN RESULTS No trials were included in the review. AUTHORS' CONCLUSIONS There are no published or ongoing randomised controlled clinical trials relevant to this review question. Therefore, in the absence of any high level evidence, clinicians should base their decisions on clinical experience and in conjunction with preferences of the individual where appropriate. This does not mean that carnitine is ineffective or should not be used in any inborn error of metabolism. However, given the lack of evidence both on the effectiveness and safety of carnitine and on the necessary dose and frequency to be prescribed, the current prescribing practice should continue to be observed and monitored with care until further evidence is available. Methodologically sound trials, reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement, are required. It should be considered whether placebo-controlled trials in potentially lethal diseases, e.g. carnitine transporter disorder or glutaric aciduria type I, are ethical.
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Affiliation(s)
- Mona Nasser
- Department of Health Information, Institute for Quality and Efficiency in Health care, Dillenburger Street, 27, D-51105, Köln, Germany, D-51105.
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Abstract
Metabolic myopathies are inborn errors of metabolism that result in impaired energy production due to defects in glycogen, lipid, mitochondrial, and possibly adenine nucleotide metabolism. Fatty acid oxidation defects (FAOD), glycogen storage disease, and mitochondrial myopathies represent the 3 main groups of disorders, and some consider myoadenylate deaminase (AMPD1 deficiency) to be a metabolic myopathy. Clinically, a variety of neuromuscular presentations are seen at different ages of life. Newborns and infants commonly present with hypotonia and multisystem involvement (liver and brain), whereas onset later in life usually presents with exercise intolerance with or without progressive muscle weakness and myoglobinuria. In general, the glycogen storage diseases result in high-intensity exercise intolerance, whereas the FAODs and the mitochondrial myopathies manifest predominately during endurance-type activity or under fasted or other metabolically stressful conditions. The clinical examination is often normal, and testing requires various combinations of exercise stress testing, serum creatine kinase activity and lactate concentration determination, urine organic acids, muscle biopsy, neuroimaging, and specific genetic testing for the diagnosis of a specific metabolic myopathy. Prenatal screening is available in many countries for several of the FAODs through liquid chromatography-tandem mass spectrometry. Early identification of these conditions with lifestyle measures, nutritional intervention, and cofactor treatment is important to prevent or delay the onset of muscle weakness and to avoid potential life-threatening complications such as rhabdomyolysis with resultant renal failure or hepatic failure. This article will review the key clinical features, diagnostic tests, and treatment recommendations for the more common metabolic myopathies, with an emphasis on mitochondrial myopathies.
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Wikoff WR, Gangoiti JA, Barshop BA, Siuzdak G. Metabolomics identifies perturbations in human disorders of propionate metabolism. Clin Chem 2007; 53:2169-76. [PMID: 17951291 DOI: 10.1373/clinchem.2007.089011] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND We applied untargeted mass spectrometry-based metabolomics to the diseases methylmalonic acidemia (MMA) and propionic acidemia (PA). METHODS We used a screening platform that used untargeted, mass-based metabolomics of methanol-extracted plasma to find significantly different molecular features in human plasma samples from MMA and PA patients and from healthy individuals. Capillary reverse phase liquid chromatography (4 microL/min) was interfaced to a TOF mass spectrometer, and data were processed using nonlinear alignment software (XCMS) and an online database (METLIN) to find and identify metabolites differentially regulated in disease. RESULTS Of the approximately 3500 features measured, propionyl carnitine was easily identified as the best biomarker of disease (P value 1.3 x 10(-18)), demonstrating the proof-of-concept use of untargeted metabolomics in clinical chemistry discovery. Five additional acylcarnitine metabolites showed significant differentiation between plasma from patients and healthy individuals, and gamma-butyrobetaine was highly increased in a subset of patients. Two acylcarnitine metabolites and numerous unidentified species differentiate MMA and PA. Many metabolites that do not appear in any public database, and that remain unidentified, varied significantly between normal, MMA, and PA, underscoring the complex downstream metabolic effects resulting from the defect in a single enzyme. CONCLUSIONS This proof-of-concept study demonstrates that metabolomics can expand the range of metabolites associated with human disease and shows that this method may be useful for disease diagnosis and patient clinical evaluation.
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Affiliation(s)
- William R Wikoff
- Department of Molecular Biology and The Center for Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92037, USA
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