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Wanders RJA, Vaz FM, Ferdinandusse S, van Kuilenburg ABP, Kemp S, van Karnebeek CD, Waterham HR, Houtkooper RH. Translational Metabolism: A multidisciplinary approach towards precision diagnosis of inborn errors of metabolism in the omics era. J Inherit Metab Dis 2019; 42:197-208. [PMID: 30723938 DOI: 10.1002/jimd.12008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/27/2018] [Accepted: 10/11/2018] [Indexed: 12/19/2022]
Abstract
The laboratory diagnosis of inborn errors of metabolism has been revolutionized in recent years, thanks to the amazing developments in the field of DNA sequencing including whole exome and whole genome sequencing (WES and WGS). Interpretation of the results coming from WES and/or WGS analysis is definitely not trivial especially since the biological relevance of many of the variants identified by WES and/or WGS, have not been tested experimentally and prediction programs like POLYPHEN-2 and SIFT are far from perfect. Correct interpretation of WES and/or WGS results can only be achieved by performing functional studies at multiple levels (different metabolomics platforms, enzymology, in vitro and in vivo flux analysis), often requires studies in model organisms like zebra fish, Caenorhabditis elegans, Saccharomyces cerevisiae, mutant mice and others, and also requires the input of many different disciplines to make this Translational Metabolism approach effective.
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Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Frederic M Vaz
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - André B P van Kuilenburg
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Stephan Kemp
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Clara D van Karnebeek
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
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Vasiljevski ER, Summers MA, Little DG, Schindeler A. Lipid storage myopathies: Current treatments and future directions. Prog Lipid Res 2018; 72:1-17. [PMID: 30099045 DOI: 10.1016/j.plipres.2018.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/20/2018] [Accepted: 08/06/2018] [Indexed: 10/28/2022]
Abstract
Lipid storage myopathies (LSMs) are a heterogeneous group of genetic disorders that present with abnormal lipid storage in multiple body organs, typically muscle. Patients can clinically present with cardiomyopathy, skeletal muscle weakness, myalgia, and extreme fatigue. An early diagnosis is crucial, as some LSMs can be managed by simple nutraceutical supplementation. For example, high dosage l-carnitine is an effective intervention for patients with Primary Carnitine Deficiency (PCD). This review discusses the clinical features and management practices of PCD as well as Neutral Lipid Storage Disease (NLSD) and Multiple Acyl-CoA Dehydrogenase Deficiency (MADD). We provide a detailed summary of current clinical management strategies, highlighting issues of high-risk contraindicated treatments with case study examples not previously reviewed. Additionally, we outline current preclinical studies providing disease mechanistic insight. Lastly, we propose that a number of other conditions involving lipid metabolic dysfunction that are not classified as LSMs may share common features. These include Neurofibromatosis Type 1 (NF1) and autoimmune myopathies, including Polymyositis (PM), Dermatomyositis (DM), and Inclusion Body Myositis (IBM).
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Affiliation(s)
- Emily R Vasiljevski
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Matthew A Summers
- Bone Biology Division, The Garvan Institute of Medical Research, Darlinghurst, NSW, Australia; St Vincent's Clinical School, University of New South Wales, Faculty of Medicine, Sydney, NSW, Australia
| | - David G Little
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Aaron Schindeler
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia.
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Yamada K, Kobayashi H, Bo R, Purevsuren J, Mushimoto Y, Takahashi T, Hasegawa Y, Taketani T, Fukuda S, Yamaguchi S. Efficacy of bezafibrate on fibroblasts of glutaric acidemia type II patients evaluated using an in vitro probe acylcarnitine assay. Brain Dev 2017; 39:48-57. [PMID: 27591119 DOI: 10.1016/j.braindev.2016.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 07/29/2016] [Accepted: 08/10/2016] [Indexed: 11/19/2022]
Abstract
INTRODUCTION We evaluated the effects of bezafibrate (BEZ) on β-oxidation in fibroblasts obtained from patients with glutaric acidemia type II (GA2) of various clinical severities using an in vitro probe (IVP) assay. METHODS Cultured fibroblasts from 12 patients with GA2, including cases of the neonatal-onset type both with and without congenital anomalies (the prenatal- and neonatal-onset forms, respectively), the infantile-onset, and the myopathic forms, were studied. The IVP assay was performed by measuring acylcarnitines (ACs) in the cell culture medium of fibroblasts incubated with palmitic acid for 96h in the presence of 0-800μM BEZ using tandem mass spectrometry. RESULTS The IVP assay showed that 100μM BEZ markedly reduced the level of palmitoylcarnitine (C16) in the neonatal-onset, infantile-onset, and myopathic forms of GA2, either increasing or maintaining a high level of acetylcarnitine (C2), which serves as an index of energy production via β-oxidation. In the prenatal-onset form, although a small reduction of C16 was also observed in the presence of 100μM BEZ, the level of C2 remained low. At concentrations higher than 100μM, BEZ further decreased the level of ACs including C16, but a concentration over 400μM decreased the level of C2 in most cases. DISCUSSION BEZ at 100μM was effective for all GA2 phenotypes except for the prenatal-onset form, as a reduction of C16 without deterioration of C2 is considered to indicate improvement of β-oxidation. The effects of higher doses BEZ could not be estimated by the IVP assay but might be small or nonexistent.
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Affiliation(s)
- Kenji Yamada
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan.
| | - Hironori Kobayashi
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Ryosuke Bo
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Jamiyan Purevsuren
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Yuichi Mushimoto
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Tomoo Takahashi
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Yuki Hasegawa
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Takeshi Taketani
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Seiji Fukuda
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
| | - Seiji Yamaguchi
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Shimane, Japan
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Tein I. Impact of fatty acid oxidation disorders in child neurology: from Reye syndrome to Pandora's box. Dev Med Child Neurol 2015; 57:304-6. [PMID: 25761966 DOI: 10.1111/dmcn.12717] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ingrid Tein
- Division of Neurology, Department of Pediatrics, Laboratory Medicine and Pathobiology, The Hospital for Sick Children, The University of Toronto, Toronto, Ontario, Canada
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Functional analysis of iPSC-derived myocytes from a patient with carnitine palmitoyltransferase II deficiency. Biochem Biophys Res Commun 2014; 448:175-81. [PMID: 24780397 DOI: 10.1016/j.bbrc.2014.04.084] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 04/16/2014] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Carnitine palmitoyltransferase II (CPT II) deficiency is an inherited disorder involving β-oxidation of long-chain fatty acids (FAO), which leads to rhabdomyolysis and subsequent acute renal failure. The detailed mechanisms of disease pathogenesis remain unknown; however, the availability of relevant human cell types for investigation, such as skeletal muscle cells, is limited, and the development of novel disease models is required. METHODS We generated human induced pluripotent stem cells (hiPSCs) from skin fibroblasts of a Japanese patient with CPT II deficiency. Mature myocytes were differentiated from the patient-derived hiPSCs by introducing myogenic differentiation 1 (MYOD1), the master transcriptional regulator of myocyte differentiation. Using an in vitro acylcarnitine profiling assay, we investigated the effects of a hypolipidemic drug, bezafibrate, and heat stress on mitochondrial FAO in CPT II-deficient myocytes and controls. RESULTS CPT II-deficient myocytes accumulated more palmitoylcarnitine (C16) than did control myocytes. Heat stress, induced by incubation at 38°C, leads to a robust increase of C16 in CPT II-deficient myocytes, but not in controls. Bezafibrate reduced the amount of C16 in control and CPT II-deficient myocytes. DISCUSSION In this study, we induced differentiation of CPT II-deficient hiPSCs into mature myocytes in a highly efficient and reproducible manner and recapitulated some aspects of the disease phenotypes of CPT II deficiency in the myocyte disease models. This approach addresses the challenges of modeling the abnormality of FAO in CPT II deficiency using iPSC technology and has the potential to revolutionize translational research in this field.
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Ørngreen MC, Madsen KL, Preisler N, Andersen G, Vissing J, Laforêt P. Bezafibrate in skeletal muscle fatty acid oxidation disorders: a randomized clinical trial. Neurology 2014; 82:607-13. [PMID: 24453079 DOI: 10.1212/wnl.0000000000000118] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE To assess whether bezafibrate increases fatty acid oxidation (FAO) and lowers heart rate (HR) during exercise in patients with carnitine palmitoyltransferase (CPT) II and very long-chain acyl-CoA dehydrogenase (VLCAD) deficiencies. METHODS This was a 3-month, randomized, double-blind, crossover study of bezafibrate in patients with CPT II (n = 5) and VLCAD (n = 5) deficiencies. Primary outcome measures were changes in FAO, measured with stable-isotope methodology and indirect calorimetry, and changes in HR during exercise. RESULTS Bezafibrate lowered low-density lipoprotein, triglyceride, and free fatty acid concentrations; however, there were no changes in palmitate oxidation, FAO, or HR during exercise. CONCLUSION Bezafibrate does not improve clinical symptoms or FAO during exercise in patients with CPT II and VLCAD deficiencies. These findings indicate that previous in vitro studies suggesting a therapeutic potential for fibrates in disorders of FAO do not translate into clinically meaningful effects in vivo. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that bezafibrate 200 mg 3 times daily is ineffective in improving changes in FAO and HR during exercise in adults with CPT II and VLCAD deficiencies.
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Affiliation(s)
- Mette Cathrine Ørngreen
- From the Neuromuscular Clinic and Research Unit (M.C.Ø, K.L.M., N.P., G.A., J.V.), Department of Neurology, Rigshospitalet, University of Copenhagen, Denmark; and Centre de Référence de pathologie neuromusculaire Paris-Est (P.L.), Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, France
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Gacias M, Pérez-Martí A, Pujol-Vidal M, Marrero PF, Haro D, Relat J. PGC-1β regulates mouse carnitine-acylcarnitine translocase through estrogen-related receptor α. Biochem Biophys Res Commun 2012; 423:838-43. [PMID: 22713466 DOI: 10.1016/j.bbrc.2012.06.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 06/12/2012] [Indexed: 11/25/2022]
Abstract
Carnitine/acylcarnitine translocase (CACT) is a mitochondrial-membrane carrier proteins that mediates the transport of acylcarnitines into the mitochondrial matrix for their oxidation by the mitochondrial fatty acid-oxidation pathway. CACT deficiency causes a variety of pathological conditions, such as hypoketotic hypoglycemia, cardiac arrest, hepatomegaly, hepatic dysfunction and muscle weakness, and it can be fatal in newborns and infants. Here we report that expression of the Cact gene is induced in mouse skeletal muscle after 24h of fasting. To gain insight into the control of Cact gene expression, we examine the transcriptional regulation of the mouse Cact gene. We show that the 5'-flanking region of this gene is transcriptionally active and contains a consensus sequence for the estrogen-related receptor (ERR), a member of the nuclear receptor family of transcription factors. This sequence binds ERRαin vivo and in vitro and is required for the activation of Cact expression by the peroxisome proliferator-activated receptor gamma coactivator (PGC)-1/ERR axis. We also demonstrate that XTC790, the inverse agonist of ERRα, specifically blocks Cact activation by PGC-1β in C2C12 cells.
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Affiliation(s)
- Mar Gacias
- Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona, Spain
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Potter BK, Little J, Chakraborty P, Kronick JB, Evans J, Frei J, Sutherland SC, Wilson K, Wilson BJ. Variability in the clinical management of fatty acid oxidation disorders: results of a survey of Canadian metabolic physicians. J Inherit Metab Dis 2012; 35:115-23. [PMID: 21630065 DOI: 10.1007/s10545-011-9352-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 04/27/2011] [Accepted: 05/11/2011] [Indexed: 12/31/2022]
Abstract
INTRODUCTION There is little robust empirical evidence on which to base treatment recommendations for fatty acid oxidation disorders. While consensus guidelines are important, understanding areas where there is a lack of consensus is also critical to inform priorities for future evaluative research. METHODS We surveyed Canadian metabolic physicians on the treatment of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency, long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, and mitochondrial trifunctional protein (MTP) deficiency. We ascertained physicians' opinions on the use of different interventions for the long-term management of patients as well as for the management of acute illness, focusing on identifying interventions characterized by high variability in opinions. We also investigated factors influencing treatment decisions. RESULTS We received 18 responses (response rate 45%). Participants focused on avoidance of fasting and increased meal frequency as interventions for the management of MCAD deficiency. For the long-chain disorders, avoidance of fasting remained the most consistently endorsed intervention, with additional highly endorsed treatments differing for VLCAD versus LCHAD/MTP deficiency. L-carnitine supplementation and restriction of dietary fat were characterized by high variability in physicians' opinions, as were several interventions specific to long-chain disorders. Social factors and patient characteristics were important influences on treatment decisions. CONCLUSIONS Based on our findings we suggest that high priority treatments for rigorous effectiveness studies could include L-carnitine supplementation (MCAD and LCHAD/MTP deficiencies), restriction of dietary fat, and, for the long-chain disorders, feeding practices for breastfed infants and the use of various supplements (essential fatty acids, carbohydrates, cornstarch, multivitamins).
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Affiliation(s)
- Beth K Potter
- Department of Epidemiology & Community Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, Ontario, Canada.
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Illsinger S, Janzen N, Lücke T, Bednarczyk J, Schmidt KH, Hoy L, Sander J, Das AM. Cyclosporine A: impact on mitochondrial function in endothelial cells. Clin Transplant 2010; 25:584-93. [PMID: 20633034 DOI: 10.1111/j.1399-0012.2010.01301.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Although cyclosporine A (CSA) is considered to be an efficient immunosuppressive compound in transplantation, vascular side effects like arterial hypertension, neurologic complications and other adverse reactions occur. Interference of CSA with mitochondrial function may be responsible for these side effects. METHODS We evaluated the effect of CSA on mitochondrial and glycolytic function by measuring fatty acid oxidation (FAO), activities of respiratory chain complexes (RC) and citratesynthase (CS), lactate/pyruvate-ratios, energy-rich phosphates as well as activities of some glycolytic enzymes in human umbilical vein endothelial cells. RESULTS After 48 h of CSA incubation, global FAO, RC-complexes 1 + 3; 4 and 5 as well as CS were compromised while energy charges were not reduced. Lactate/pyruvate-ratios increased; cellular lactate dehydrogenase (LDH)-, hexokinase- and phosphofructokinase-activities were not impaired by CSA. Moderate cellular toxicity, assessed by LDH leakage, appeared only at the highest CSA concentration. CONCLUSION Part of CSA toxicity may arise from alterations in mitochondrial function as judged by impaired FAO and respiratory chain enzymes. To some extent, energy balance seems to be maintained by cytosolic energy production. Although only demonstrated for endothelial cells, it is conceivable that such effects will alter energy metabolism of different organs with high oxidative energy demands.
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Affiliation(s)
- Sabine Illsinger
- Clinic for Pediatric Kidney-, Liver- and Metabolic Diseases, Hannover Medical School, Hannover, Germany
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Inborn errors of energy metabolism associated with myopathies. J Biomed Biotechnol 2010; 2010:340849. [PMID: 20589068 PMCID: PMC2877206 DOI: 10.1155/2010/340849] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 01/19/2010] [Accepted: 02/22/2010] [Indexed: 12/31/2022] Open
Abstract
Inherited neuromuscular disorders affect approximately one in 3,500 children. Structural muscular defects are most common; however functional impairment of skeletal and cardiac muscle in both children and adults may be caused by inborn errors of energy metabolism as well. Patients suffering from metabolic myopathies due to compromised energy metabolism may present with exercise intolerance, muscle pain, reversible or progressive muscle weakness, and myoglobinuria. In this review, the physiology of energy metabolism in muscle is described, followed by the presentation of distinct disorders affecting skeletal and cardiac muscle: glycogen storage diseases types III, V, VII, fatty acid oxidation defects, and respiratory chain defects (i.e., mitochondriopathies). The diagnostic work-up and therapeutic options in these disorders are discussed.
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Li H, Fukuda S, Hasegawa Y, Kobayashi H, Purevsuren J, Mushimoto Y, Yamaguchi S. Effect of heat stress and bezafibrate on mitochondrial beta-oxidation: comparison between cultured cells from normal and mitochondrial fatty acid oxidation disorder children using in vitro probe acylcarnitine profiling assay. Brain Dev 2010; 32:362-70. [PMID: 19589653 DOI: 10.1016/j.braindev.2009.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 05/26/2009] [Accepted: 06/02/2009] [Indexed: 12/31/2022]
Abstract
Hyperpyrexia occasionally triggers acute life-threatening encephalopathy-like illnesses, including influenza-associated encephalopathy (IAE) in childhood, and can be responsible for impaired fatty acid beta-oxidation (FAO). In this regard, patients with impaired FAO may be more susceptible to febrile episodes. The effects of heat stress and a hypolipidemic drug, bezafibrate, on mitochondrial FAO were investigated using cultured cells from children with FAO disorders and from normal controls, using an in vitro probe acylcarnitine (AC) profiling assay. Fibroblasts were incubated in medium loaded with unlabelled palmitic acid for 96 h at 37 and 41 degrees C, with or without bezafibrate. AC profiles in culture medium were analyzed by electrospray ionization tandem mass spectrometry. Heat stress, introduced by 41 degrees C, significantly increased acetylcarnitine (C2) but slightly decreased the other acylcarnitines (ACs) in controls and medium-chain acyl-CoA dehydrogenase (MCAD)-deficient cells. On the other hand, in very long-chain acyl-CoA dehydrogenase (VLCAD)-deficient cells, accumulation of long-chain ACs were enhanced at 41 degrees C, compared with that at 37 degrees C. In contrast, bezafibrate decreased long-chain ACs with significant increase of C2 in both control and VLCAD-deficient cells at 37 degrees C. These data suggest that heat stress specifically inhibits long-chain FAO, whereas bezafibrate recovers the impaired FAO. Our approach is a simple and promising strategy to evaluate the effects of heat stress or therapeutic drugs on mitochondrial FAO.
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Affiliation(s)
- Hong Li
- Department of Pediatrics, Shimane University School of Medicine, Izumo, Shimane, Japan
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Shchelochkov O, Wong LJ, Shaibani A, Shinawi M. Atypical presentation of VLCAD deficiency associated with a novel ACADVL splicing mutation. Muscle Nerve 2009; 39:374-82. [PMID: 19208414 DOI: 10.1002/mus.21157] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Very long chain acyl-CoA dehydrogenase (VLCAD) deficiency is an autosomal recessive inborn error of metabolism characterized by impaired mitochondrial beta-oxidation of fatty acids with a chain length between 14 and 18 carbons. While expansion of newborn screening has improved our ability to detect VLCAD deficiency in early childhood, the late-onset form of the disease still presents a significant diagnostic challenge. We report a 20-year-old female with VLCAD deficiency who first presented in infancy with hypoketotic hypoglycemia. In childhood the patient developed complex partial seizures that were aggravated by Lamotrigine treatment. The clinical course in early adulthood was complicated by recurrent, often unprovoked, episodes of rhabdomyolysis and myoglobinuria. In addition, she suffered from chronic myalgia, muscle weakness, and diffuse abdominal tenderness. A muscle biopsy revealed accumulation of fat droplets. Her acylcarnitine profile showed significantly elevated C14, C14:1, C16, and C18-carnitines. Sequence analysis of ACADVL revealed a heterozygous recurrent mutation c.848T>C (p.V283A) and a heterozygous novel splice mutation c.879-8T>A that results in the inclusion of six nucleotides from intron 9 into the transcript sequence. The molecular characterization of this novel mutation and its correlation with the clinical phenotype are discussed.
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Affiliation(s)
- Oleg Shchelochkov
- Department of Molecular and Human Genetics, One Baylor Plaza, Room T619, Houston, Texas 77030, USA
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Labarthe F. Nouvelles approches thérapeutiques des anomalies de la β-oxydation mitochondriale. Arch Pediatr 2008; 15:608-10. [DOI: 10.1016/s0929-693x(08)71849-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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