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Pasqua T, Rocca C, Giglio A, Angelone T. Cardiometabolism as an Interlocking Puzzle between the Healthy and Diseased Heart: New Frontiers in Therapeutic Applications. J Clin Med 2021; 10:721. [PMID: 33673114 PMCID: PMC7918460 DOI: 10.3390/jcm10040721] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/14/2022] Open
Abstract
Cardiac metabolism represents a crucial and essential connecting bridge between the healthy and diseased heart. The cardiac muscle, which may be considered an omnivore organ with regard to the energy substrate utilization, under physiological conditions mainly draws energy by fatty acids oxidation. Within cardiomyocytes and their mitochondria, through well-concerted enzymatic reactions, substrates converge on the production of ATP, the basic chemical energy that cardiac muscle converts into mechanical energy, i.e., contraction. When a perturbation of homeostasis occurs, such as an ischemic event, the heart is forced to switch its fatty acid-based metabolism to the carbohydrate utilization as a protective mechanism that allows the maintenance of its key role within the whole organism. Consequently, the flexibility of the cardiac metabolic networks deeply influences the ability of the heart to respond, by adapting to pathophysiological changes. The aim of the present review is to summarize the main metabolic changes detectable in the heart under acute and chronic cardiac pathologies, analyzing possible therapeutic targets to be used. On this basis, cardiometabolism can be described as a crucial mechanism in keeping the physiological structure and function of the heart; furthermore, it can be considered a promising goal for future pharmacological agents able to appropriately modulate the rate-limiting steps of heart metabolic pathways.
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Affiliation(s)
- Teresa Pasqua
- Department of Health Science, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy;
| | - Carmine Rocca
- Laboratory of Cellular and Molecular Cardiovascular Pathophysiology, Department of Biology, E. and E.S. (Di.B.E.S.T.), University of Calabria, 87036 Rende (CS), Italy
| | - Anita Giglio
- Department of Biology, E. and E.S. (Di.B.E.S.T.), University of Calabria, 87036 Rende (CS), Italy;
| | - Tommaso Angelone
- Laboratory of Cellular and Molecular Cardiovascular Pathophysiology, Department of Biology, E. and E.S. (Di.B.E.S.T.), University of Calabria, 87036 Rende (CS), Italy
- National Institute of Cardiovascular Research (I.N.R.C.), 40126 Bologna, Italy
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L-Carnitine in Drosophila: A Review. Antioxidants (Basel) 2020; 9:antiox9121310. [PMID: 33371457 PMCID: PMC7767417 DOI: 10.3390/antiox9121310] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022] Open
Abstract
L-Carnitine is an amino acid derivative that plays a key role in the metabolism of fatty acids, including the shuttling of long-chain fatty acyl CoA to fuel mitochondrial β-oxidation. In addition, L-carnitine reduces oxidative damage and plays an essential role in the maintenance of cellular energy homeostasis. L-carnitine also plays an essential role in the control of cerebral functions, and the aberrant regulation of genes involved in carnitine biosynthesis and mitochondrial carnitine transport in Drosophila models has been linked to neurodegeneration. Drosophila models of neurodegenerative diseases provide a powerful platform to both unravel the molecular pathways that contribute to neurodegeneration and identify potential therapeutic targets. Drosophila can biosynthesize L-carnitine, and its carnitine transport system is similar to the human transport system; moreover, evidence from a defective Drosophila mutant for one of the carnitine shuttle genes supports the hypothesis of the occurrence of β-oxidation in glial cells. Hence, Drosophila models could advance the understanding of the links between L-carnitine and the development of neurodegenerative disorders. This review summarizes the current knowledge on L-carnitine in Drosophila and discusses the role of the L-carnitine pathway in fly models of neurodegeneration.
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Koca M, Erden A, Armagan B, Sari A, Yildiz F, Ozdamar S, Kalyoncu U, Karadag O. Two cases of glutaric aciduria type II: how to differentiate from inflammatory myopathies? Acta Clin Belg 2019; 74:451-455. [PMID: 30451603 DOI: 10.1080/17843286.2018.1547244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Muscle weakness is a nonspecific finding of myopathy of any etiology that include iatrogenic, toxic, endocrinological, infectious, immunologic, and metabolic disorders. Among the metabolic myopathies glutaric aciduria type II (GAII) is an autosomal recessively inherited rare disorder of fatty acid and amino acid metabolisms. The late onset form is heterogeneous in terms of symptomatology and severity and for the cases that chronic manifestations of lipid storage myopathy are the only clues for the disease, differential diagnosis can be challenging. Here we report two cases of GAII: the first one was 18-year old boy who presented with proximal muscle weakness and in another center, he was diagnosed as polymyositis and treated with immunosuppressive therapies. He admitted to our clinic with ongoing muscle weakness and symptoms that were related to the side effects of immunosuppressive therapies. The second case was also presented with muscle weakness. For both cases, muscle biopsies and urinary organic acid analyses were consistent with the diagnosis of GAII. To differentiate inflammatory myositis from non-inflammatory myopathies; rheumatic symptoms, accompanying complaints of the patient and autoantibody positivity can be helpful. To our knowledge this is the first report to underline the differential diagnosis of inflammatory myopathies from metabolic myopathies.
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Affiliation(s)
- Meltem Koca
- Faculty of Medicine, Department of Internal Medicine, Hacettepe University, Ankara, Turkey
| | - Abdulsamet Erden
- Faculty of Medicine, Department of Rheumatology, Hacettepe University, Ankara, Turkey
| | - Berkan Armagan
- Faculty of Medicine, Department of Rheumatology, Hacettepe University, Ankara, Turkey
| | - Alper Sari
- Faculty of Medicine, Department of Rheumatology, Hacettepe University, Ankara, Turkey
| | - Fatih Yildiz
- Department of Rheumatology, Saglik Bilimleri Universitesi, Van Egitim ve Arastirma Hastanesi, Van, Turkey
| | - Sevim Ozdamar
- Faculty of Medicine, Department of Neurology, Hacettepe University, Ankara, Turkey
| | - Umut Kalyoncu
- Faculty of Medicine, Department of Rheumatology, Hacettepe University, Ankara, Turkey
| | - Omer Karadag
- Faculty of Medicine, Department of Rheumatology, Hacettepe University, Ankara, Turkey
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4
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Carnitine palmitoyltransferase II deficiency with a focus on newborn screening. J Hum Genet 2018; 64:87-98. [PMID: 30514913 DOI: 10.1038/s10038-018-0530-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/23/2018] [Accepted: 10/25/2018] [Indexed: 11/08/2022]
Abstract
Carnitine palmitoyltransferase (CPT) II deficiency is one of the most common forms of mitochondrial fatty acid oxidation disorder. Its clinical phenotypes are classified into the muscle, severe infantile, and lethal neonatal forms. Among Caucasians, the muscle form predominates, and the c.338C > T (p.S113L) variant is detected in most cases, whereas among the Japanese, c.1148T > A (p.F383Y) is the variant allele occurring with the highest frequency and can apparently cause symptoms of the severe infantile form. Newborn screening (NBS) for this potentially fatal disease has not been established. We encountered an infantile case of CPT II deficiency not detected in NBS using C16 and C18:1 concentrations as indices, and therefore we adopted the (C16 + C18:1)/C2 ratio as an alternative primary index. As a result, the disease was diagnosed in nine of 31 NBS-positive subjects. The values for (C16 + C18:1)/C2 in the affected newborns partly overlapped with those in unaffected ones. Among several other indices proposed previously, C14/C3 has emerged as a more promising index. Based on these findings, nationwide NBS for CPT II deficiency using both (C16 + C18:1)/C2 and C14/C3 as indices was officially approved and started in April 2018. We diagnosed the disease in four young children presenting with symptoms of the muscle form, whose values for the new indices were not elevated. Although it is still difficult to detect all cases of the muscle form of CPT II deficiency in NBS, our system is expected to save many affected children in Japan with the severe infantile form predominating.
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Alternative respiratory chain enzymes: Therapeutic potential and possible pitfalls. Biochim Biophys Acta Mol Basis Dis 2018; 1865:854-866. [PMID: 30342157 DOI: 10.1016/j.bbadis.2018.10.012] [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: 05/20/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 01/07/2023]
Abstract
The alternative respiratory chain (aRC), comprising the alternative NADH dehydrogenases (NDX) and quinone oxidases (AOX), is found in microbes, fungi and plants, where it buffers stresses arising from restrictions on electron flow in the oxidative phosphorylation system. The aRC enzymes are also found in species belonging to most metazoan phyla, including some chordates and arthropods species, although not in vertebrates or in Drosophila. We postulated that the aRC enzymes might be deployed to alleviate pathological stresses arising from mitochondrial dysfunction in a wide variety of disease states. However, before such therapies can be contemplated, it is essential to understand the effects of aRC enzymes on cell metabolism and organismal physiology. Here we report and discuss new findings that shed light on the functions of the aRC enzymes in animals, and the unexpected benefits and detriments that they confer on model organisms. In Ciona intestinalis, the aRC is induced by hypoxia and by sulfide, but is unresponsive to other environmental stressors. When expressed in Drosophila, AOX results in impaired survival under restricted nutrition, in addition to the previously reported male reproductive anomalies. In contrast, it confers cold resistance to developing and adult flies, and counteracts cell signaling defects that underlie developmental dysmorphologies. The aRC enzymes may also influence lifespan and stress resistance more generally, by eliciting or interfering with hormetic mechanisms. In sum, their judicious use may lead to major benefits in medicine, but this will require a thorough characterization of their properties and physiological effects.
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Abbreviated half-lives and impaired fuel utilization in carnitine palmitoyltransferase II variant fibroblasts. PLoS One 2015; 10:e0119936. [PMID: 25781464 PMCID: PMC4364069 DOI: 10.1371/journal.pone.0119936] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 01/28/2015] [Indexed: 12/17/2022] Open
Abstract
Carnitine palmitoyltransferase II (CPT II) deficiency is one of the most common causes of fatty acid oxidation metabolism disorders. However, the molecular mechanism between CPT2 gene polymorphisms and metabolic stress has not been fully clarified. We previously reported that a number of patients show a thermal instable phenotype of compound hetero/homozygous variants of CPT II. To understand the mechanism of the metabolic disorder resulting from CPT II deficiency, the present study investigated CPT II variants in patient fibroblasts, [c.1102 G>A (p.V368I)] (heterozygous), [c.1102 G>A (p.V368I)] (homozygous), and [c.1055 T>G (p.F352C)] (heterozygous) + [c.1102 G>A (p.V368I)] (homozygous) compared with fibroblasts from healthy controls. CPT II variants exerted an effect of dominant negative on the homotetrameric proteins that showed thermal instability, reduced residual enzyme activities and a short half-life. Moreover, CPT II variant fibroblasts showed a significant decrease in fatty acid β-oxidation and adenosine triphosphate generation, combined with a reduced mitochondrial membrane potential, resulting in cellular apoptosis. Collectively, our data indicate that the CPT II deficiency induces an energy crisis of the fatty acid metabolic pathway. These findings may contribute to the elucidation of the genetic factors involved in metabolic disorder encephalopathy caused by the CPT II deficiency.
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Schulz JG, Laranjeira A, Van Huffel L, Gärtner A, Vilain S, Bastianen J, Van Veldhoven PP, Dotti CG. Glial β-oxidation regulates Drosophila energy metabolism. Sci Rep 2015; 5:7805. [PMID: 25588812 PMCID: PMC4295106 DOI: 10.1038/srep07805] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 12/03/2014] [Indexed: 12/26/2022] Open
Abstract
The brain's impotence to utilize long-chain fatty acids as fuel, one of the dogmas in neuroscience, is surprising, since the nervous system is the tissue most energy consuming and most vulnerable to a lack of energy. Challenging this view, we here show in vivo that loss of the Drosophila carnitine palmitoyltransferase 2 (CPT2), an enzyme required for mitochondrial β-oxidation of long-chain fatty acids as substrates for energy production, results in the accumulation of triacylglyceride-filled lipid droplets in adult Drosophila brain but not in obesity. CPT2 rescue in glial cells alone is sufficient to restore triacylglyceride homeostasis, and we suggest that this is mediated by the release of ketone bodies from the rescued glial cells. These results demonstrate that the adult brain is able to catabolize fatty acids for cellular energy production.
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Affiliation(s)
- Joachim G Schulz
- VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Antonio Laranjeira
- VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Leen Van Huffel
- VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Annette Gärtner
- VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Sven Vilain
- VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Jarl Bastianen
- VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Paul P Van Veldhoven
- Laboratory of Lipid Biochemistry, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Carlos G Dotti
- 1] VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium [2] Centro Biología Molecular "Severo Ochoa" CSIC-UAM, Madrid, Spain
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8
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Yamamoto T, Tanaka H, Emoto Y, Umehara T, Fukahori Y, Kuriu Y, Matoba R, Ikematsu K. Carnitine palmitoyltransferase 2 gene polymorphism is a genetic risk factor for sudden unexpected death in infancy. Brain Dev 2014; 36:479-83. [PMID: 23969168 DOI: 10.1016/j.braindev.2013.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 06/26/2013] [Accepted: 07/18/2013] [Indexed: 12/30/2022]
Abstract
RATIONALE Carnitine palmitoyltransferase (CPT) II is one of a pivotal enzyme in mitochondrial fatty acid oxidation, which is essential for energy production during simultaneous glucose sparing and a requirement for major energy supply, such as prolonged fasting or exercise. When infants require more energy than provided by the glycolytic system, they rely on the mitochondrial fatty acid oxidation pathway. Mutations of the CPT2 gene have been reported to cause sudden unexpected death in infancy (SUDI). A thermolabile phenotype of a CPT2 polymorphism (F352C) has been recently reported to reduce CPT II enzyme activity. The F352C variant results in energy crisis at high temperature and is suspected as a risk factor for acute encephalopathy. However, a relationship between CPT2 gene polymorphism and SUDI has not been described. METHODS Single nucleotide polymorphisms of the CPT2 gene were investigated among 54 SUDI cases and 200 healthy volunteers. RESULTS The frequency of the C allele was significantly higher in the SUDI group than in the control group [25.0% vs 16.0%, odds ratio (OR)=1.75, 95% confidence interval (CI)=1.05-2.92, p=0.030). The frequency of the F352C homozygote was significantly higher in the SUDI group than in control group (11.1% vs 3.5%, OR=3.45, 95% CI=1.11-10.73, p=0.036). CONCLUSION The F352C CPT2 variant might be a genetic risk factor for SUDI.
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Affiliation(s)
- Takuma Yamamoto
- Division of Forensic Pathology and Science, Unit of Social Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Japan; Department of Legal Medicine, Osaka University Graduate School of Medicine, Japan.
| | - Hidekazu Tanaka
- Laboratory of Pharmacology, Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Japan
| | - Yuko Emoto
- Department of Legal Medicine, Osaka University Graduate School of Medicine, Japan
| | - Takahiro Umehara
- Division of Forensic Pathology and Science, Unit of Social Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Japan
| | - Yuki Fukahori
- Division of Forensic Pathology and Science, Unit of Social Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Japan; Forensic Science Laboratory, Nagasaki Prefectural Police Headquarters, Japan
| | - Yukiko Kuriu
- Department of Legal Medicine, Osaka University Graduate School of Medicine, Japan
| | - Ryoji Matoba
- Department of Legal Medicine, Osaka University Graduate School of Medicine, Japan
| | - Kazuya Ikematsu
- Division of Forensic Pathology and Science, Unit of Social Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Japan
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Abstract
Recognition of fatty acid oxidation (FAO) disorders is important for the pediatric neurologist as they present with a spectrum of clinical disorders, including progressive lipid storage myopathy, recurrent myoglobinuria, neuropathy, progressive cardiomyopathy, recurrent hypoglycemic hypoketotic encephalopathy or Reye-like syndrome, seizures, and mental retardation. They constitute a critical group of diseases because they are potentially rapidly fatal and a source of major morbidity. There is frequently a family history of sudden infant death syndrome in siblings. Early recognition and prompt institution of therapy and appropriate preventive measures, and in certain cases specific therapy, may be life-saving and may significantly decrease long-term morbidity, particularly with respect to CNS sequelae. All currently known conditions are inherited as autosomal recessive traits. There are now at least 25 enzymes and specific transport proteins in the β-oxidation pathway and 18 have been associated with human disease. The most common defect is medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, which had an incidence of 1 in 8930 live births in one series. The identification of serum acylcarnitines by electrospray ionization-tandem mass spectrometry of dried blood spots on filter paper in newborn screening programs has significantly enhanced the early recognition of these disorders.
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Affiliation(s)
- Ingrid Tein
- Neurometabolic Clinic and Research Laboratory, Division of Neurology and Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Canada.
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10
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Olpin SE. Pathophysiology of fatty acid oxidation disorders and resultant phenotypic variability. J Inherit Metab Dis 2013; 36:645-58. [PMID: 23674167 PMCID: PMC7101856 DOI: 10.1007/s10545-013-9611-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/27/2013] [Accepted: 04/10/2013] [Indexed: 12/16/2022]
Abstract
Fatty acids are a major fuel for the body and fatty acid oxidation is particularly important during fasting, sustained aerobic exercise and stress. The myocardium and resting skeletal muscle utilise long-chain fatty acids as a major source of energy. Inherited disorders affecting fatty acid oxidation seriously compromise the function of muscle and other highly energy-dependent tissues such as brain, nerve, heart, kidney and liver. Such defects encompass a wide spectrum of clinical disease, presenting in the neonatal period or infancy with recurrent hypoketotic hypoglycaemic encephalopathy, liver dysfunction, hyperammonaemia and often cardiac dysfunction. In older children, adolescence or adults there is often exercise intolerance with episodic myalgia or rhabdomyolysis in association with prolonged aerobic exercise or other exacerbating factors. Some disorders are particularly associated with toxic metabolites that may contribute to encephalopathy, polyneuropathy, axonopathy and pigmentary retinopathy. The phenotypic diversity encountered in defects of fat oxidation is partly explained by genotype/phenotype correlation and certain identifiable environmental factors but there remain many unresolved questions regarding the complex interaction of genetic, epigenetic and environmental influences that dictate phenotypic expression. It is becoming increasingly clear that the view that most inherited disorders are purely monogenic diseases is a naive concept. In the future our approach to understanding the phenotypic diversity and management of patients will be more realistically achieved from a polygenic perspective.
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Affiliation(s)
- Simon E Olpin
- Department of Clinical Chemistry, Sheffield Children's Hospital, Sheffield S10 2TH, UK.
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11
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Abstract
Congenital deficiency of carnitine palmitoyltransferase (CPT) II is a disease with an autosomal recessive inheritance of phenotypic variability which depends on age at the onset of symptoms. Three entities associated with deficiency of CPT II are known: the perinatal, the infantile and the adult form. The perinatal disease is the most severe form and is invariably fatal. On the other hand, the adult CPT II clinical phenotype is benign and requires additional external triggers such as high-intensity exercise to provoke myopathic symptoms. We report a case of adult CPT II deficiency presenting with the subtle symptoms of myopathy. A 32-year-old man was admitted to the hospital complaining of muscle pain after exercise. Athletic appearance drew attention, because the patient denied practicing sport. Neurological examination revealed marked tiredness during the single-leg hop test without other abnormalities. Electromyography (EMG) and serum biochemistry were not typical for myopathy. Routine histopathological examination did not reveal any abnormalities of structure of muscle fibers. Diagnosis was established after ultrastructural and biochemical analysis which revealed changes typical for CPT II deficiency.
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12
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Yao D, Yao M, Yamaguchi M, Chida J, Kido H. Characterization of compound missense mutation and deletion of carnitine palmitoyltransferase II in a patient with adenovirus-associated encephalopathy. THE JOURNAL OF MEDICAL INVESTIGATION 2012; 58:210-8. [PMID: 21921422 DOI: 10.2152/jmi.58.210] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND In mammals, carnitine palmitoyltransferase (CPT) system is a pivotal component of energy metabolism through mitochondrial fatty acid oxidation. The majority of patients with fatal or handicapped influenza-associated encephalopathy exhibit thermolabile compound homo/heterozygous mutations of CPT II. OBJECTIVE Compound CPT II mutations, [c.647A>G (p.Q216R)], [c.1102G>A (p.V368I)], [c.1939A>G (p.M647V)] and [c.745delG (p.G249EfsX16)], were found in a patient with adenovirus-associated encephalopathy and his family. The properties of these CPT II mutations were analyzed in COS-7 cells. METHODS CPT II mutations in the patient and his family were expressed in COS-7 cells and their molecular masses, enzyme activities, thermal instabilities and half-lives were analyzed. RESULTS We identified two novel CPT II mutations in the patient, [c.647A>G (p.Q216R)] and [c.745delG (p.G249EfsX16)]. The CPT II Q216R mutation showed mild reduction of activity, thermal instability and short half-life but compound mutations with Q216R+V368I+M647V showed further enhancement of these disabilities, although mutations V368I and M647V had no such effects. CPT II mutation [c.745delG (p.G249EfsX16)] abolished enzyme activity and showed short half-life. CONCLUSION The thermal instability and short half-life of the novel CPT II mutations, [c.647A>G (p.Q216R)] and [c.745delG (p.G249EfsX16)], could play important roles in energy crisis in the pathogenesis of virus-associated encephalopathy.
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Affiliation(s)
- Dengbing Yao
- Division of Enzyme Chemistry, Institute for Enzyme Research, University of Tokushima, Tokushima, Japan
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13
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Yahyaoui R, Espinosa MG, Gómez C, Dayaldasani A, Rueda I, Roldán A, Ugarte M, Lastra G, Pérez V. Neonatal carnitine palmitoyltransferase II deficiency associated with Dandy-Walker syndrome and sudden death. Mol Genet Metab 2011; 104:414-6. [PMID: 21641254 DOI: 10.1016/j.ymgme.2011.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 10/18/2022]
Abstract
Neonatal onset of carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive, often lethal disorder of the mitochondrial beta-oxidation of long-chain fatty acids. It is a rare multiorgan disease which includes hypoketotic hypoglycemia, severe hepatomuscular symptoms, cardiac abnormalities, seizures and lethargy, as well as dysmorphic features. Until now, only 22 affected families have been described in the literature. An increasing number of mutations are being identified in the CPT2 gene, with a distinct genotype-phenotype correlation in most cases. Herein we report a new case of neonatal CPT II deficiency associated with Dandy-Walker syndrome and sudden death at 13 days of life. CPT II deficiency was suggested by acylcarnitine analysis of dried-blood on filter paper in the expanded newborn screening. Genetic analysis of the CPT2 gene identified the presence of a previously described mutation in homozygosity (c.534_558del25bpinsT). All lethal neonatal CPT II deficiency patients previously described presented severe symptoms during the first week of life, although this was not the case in our patient, who remained stable and without apparent vital risk during the first 11 days of life. The introduction of tandem mass spectrometry to newborn screening has substantially improved our ability to detect metabolic diseases in the newborn period. This case illustrates the value of expanded newborn screening in a neonate with an unusual clinical presentation, combining hydrocephalus and sudden death, that might not commonly lead to the suspicion of an inborn error of metabolism.
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Affiliation(s)
- Raquel Yahyaoui
- Clinical Laboratory, Carlos Haya University Hospital, Málaga, Spain.
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14
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Yamamoto T, Tanaka H, Kobayashi H, Okamura K, Tanaka T, Emoto Y, Sugimoto K, Nakatome M, Sakai N, Kuroki H, Yamaguchi S, Matoba R. Retrospective review of Japanese sudden unexpected death in infancy: the importance of metabolic autopsy and expanded newborn screening. Mol Genet Metab 2011; 102:399-406. [PMID: 21227726 DOI: 10.1016/j.ymgme.2010.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 12/07/2010] [Indexed: 11/29/2022]
Abstract
Sudden unexpected death in infancy is defined as sudden unexpected death occurring before 12 months of age. The common causes of sudden unexpected death in infancy are infection, cardiovascular anomaly, child abuse, and metabolic disorders. However, the many potential inherited metabolic disorders are difficult to diagnose at autopsy and may therefore be underdiagnosed as a cause of sudden unexpected death in infancy. In the present study we retrospectively reviewed 30 Japanese sudden unexpected death in infancy cases encountered between 2006 and 2009 at our institute. With postmortem blood acylcarnitine analysis and histological examination of the liver, we found two cases of long-chain fatty acid oxidation defects. Molecular analysis revealed that the one patient had a compound heterozygote for a novel mutation (p.L644S) and a disease-causing mutation (p.F383Y) in the carnitine palmitoyltransferase 2 gene. Furthermore, retrospective acylcarnitine analysis of the newborn screening card of this patient was consistent with carnitine palmitoyltransferase II deficiency. Metabolic autopsy and expanded newborn screening would be helpful for forensic scientists and pediatricians to diagnose fatty acid oxidation disorders and prevent sudden unexpected death in infancy.
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Affiliation(s)
- Takuma Yamamoto
- Department of Legal Medicine, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka 565-0871, Japan
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15
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Hori T, Fukao T, Kobayashi H, Teramoto T, Takayanagi M, Hasegawa Y, Yasuno T, Yamaguchi S, Kondo N. Carnitine palmitoyltransferase 2 deficiency: the time-course of blood and urinary acylcarnitine levels during initial L-carnitine supplementation. TOHOKU J EXP MED 2010; 221:191-5. [PMID: 20543534 DOI: 10.1620/tjem.221.191] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Carnitine palmitoyltransferase 2 (CPT2) deficiency is one of the most common mitochondrial beta-oxidation defects. A female patient with an infantile form of CPT2 deficiency first presented as having a Reye-like syndrome with hypoglycemic convulsions. Oral L-carnitine supplementation was administered since serum free carnitine level was very low (less than 10 micromol/L), indicating secondary carnitine deficiency. Her serum and urinary acylcarnitine profiles were analyzed successively to evaluate time-course effects of L-carnitine supplementation. After the first two days of L-carnitine supplementation, the serum level of free carnitine was elevated; however, the serum levels of acylcarnitines and the urinary excretion of both free carnitine and acylcarnitines remained low. A peak of the serum free carnitine level was detected on day 5, followed by a peak of acetylcarnitine on day 7, and peaks of long-chain acylcarnitines, such as C16, C18, C18:1 and C18:2 carnitines, on day 9. Thereafter free carnitine became predominant again. These peaks of the serum levels corresponded to urinary excretion peaks of free carnitine, acetylcarnitine, and medium-chain dicarboxylic carnitines, respectively. It took several days for oral L-carnitine administration to increase the serum carnitine levels, probably because the intracellular stores were depleted. Thereafter, the administration increased the excretion of abnormal acylcarnitines, some of which had accumulated within the tissues. The excretion of medium-chain dicarboxylic carnitines dramatically decreased on day 13, suggesting improvement of tissue acylcarnitine accumulation. These time-course changes in blood and urinary acylcarnitine levels after L-carnitine supplementation support the effectiveness of L-carnitine supplementation to CPT2-deficient patients.
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Affiliation(s)
- Tomohiro Hori
- Department of Pediatrics, Gifu University Graduate School of Medicine
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16
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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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17
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Meir K, Fellig Y, Meiner V, Korman SH, Shaag A, Nadjari M, Soffer D, Ariel I. Severe infantile carnitine palmitoyltransferase II deficiency in 19-week fetal sibs. Pediatr Dev Pathol 2009; 12:481-6. [PMID: 19335026 DOI: 10.2350/08-10-0548.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Antenatal presentation of carnitine palmitoyltransferase type II deficiency due to mutations in the CPT2 gene has been rarely reported. We report an Ashkenazi Jewish family with 3 terminated pregnancies for multicystic kidneys and/or hydrocephalus. Fetal autopsy after termination of the couple's 4th pregnancy (sib 2) showed renal parenchyma replaced by cysts that appeared to increase in diameter toward the medulla. Fetopsy after termination of the 7th pregnancy (sib 3) revealed micrognathia; hypospadias; cystic renal dysplasia; hepatosteatosis; and lipid accumulation in the renal tubular epithelium, myocardium, and skeletal muscle. Microvascular proliferative changes and focal polymicrogyria were seen in the brain. A beta-oxidative enzyme deficiency was suspected. CPT2 gene analysis showed a homozygous complex haplotype for the F448L mutation associated with a c.del1238_1239AG (p.Q413fs) truncating mutation in exon 4. Carnitine palmitoyltransferase type II deficiency should be included in the differential diagnosis in fetuses of Ashkenazi origin with multicystic kidneys and unusual cerebral findings.
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Affiliation(s)
- Karen Meir
- Perinatal Pathology Unit, Department of Pathology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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18
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Hissink-Muller P, Lopriore E, Boelen C, Klumper F, Duran M, Walther F. Neonatal carnitine palmitoyltransferase II deficiency: failure of treatment despite prolonged survival. BMJ Case Rep 2009; 2009:bcr02.2009.1550. [PMID: 21709843 DOI: 10.1136/bcr.02.2009.1550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Carnitine palmitoyltransferase (CPT) deficiencies are disorders of mitochondrial fatty acid oxidation (FAO). In fatty acid oxidation, long-chain fatty acids need the carnitine cycle to be transported from the cytosol to the mitochondria. In CPT II deficiency, long-chain acylcarnitines cannot be metabolised to carnitine and acyl-CoA, leading to accumulation of toxic long-chain acylcarnitines. Three clinical presentations of CPT II deficiency have been identified: the adult form, the infantile form and the neonatal form. The neonatal form of CPT II is the most severe and all reported patients died within a few days to 6 weeks after birth. The first case of a patient with neonatal CPT II deficiency surviving beyond the neonatal period is described. Unfortunately, the infant died at the age of 6 months due to untreatable cardiac arrhythmias.
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Affiliation(s)
- Petra Hissink-Muller
- Leiden University Medical Center, Pediatrics, Albinusdreef 2, Leiden, The Netherlands
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19
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Illsinger S, Lücke T, Peter M, Ruiter JPN, Wanders RJA, Deschauer M, Handig I, Wuyts W, Das AM. Carnitine-palmitoyltransferase 2 deficiency: novel mutations and relevance of newborn screening. Am J Med Genet A 2008; 146A:2925-8. [PMID: 18925671 DOI: 10.1002/ajmg.a.32545] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report on a newborn male, born at term after an uneventful pregnancy presenting with a pathological acylcarnitine profile in routine newborn screening on the third day of life. The profile showed characteristic elevations of C14:0-, C16:0-, C16:1- and C18:1-acylcarnitines, while the ratio of (C16 + C18:1)/C2 was increased, suggesting CPT2- or carnitine-acylcarnitine-translocase- deficiency. The acylcarnitine profile in blood taken on day 9 was normal with breast milk feeding. No dicarboxylic aciduria was found. In fibroblasts, the activity of CPT2 was decreased to 25%, overall oxidation of the long-chain fatty acids was reduced to 10% of control values. Sequence analysis of the CPT2 gene showed heterozygosity for two previously undescribed mutations in exon 4: c.748-749delAA (truncating), and c.1436A > G (p.Tyr479Cys; missense) mutations. The asymptomatic parents were found to be heterozygous, the mother carries the c.748-749delAA and the father the c.1436A > G mutation. The boy is now 2.5 years old; no clinical symptoms associated with the marked impairment of long-chain fatty acid oxidation have occurred. Confirmation of mitochondrial fatty acid oxidation defects from an initial abnormal newborn-screening by tandem mass spectrometry should include enzyme and, if possible, molecular genetic analysis despite a normal 2nd screening. Biochemical testing of urine (organic acids) may be unrevealing.
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Affiliation(s)
- Sabine Illsinger
- Department of Pediatric Kidney-, Liver- and Metabolic Diseases, Children's Hospital Hannover Medical School, Hannover, Germany.
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20
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Yao D, Mizuguchi H, Yamaguchi M, Yamada H, Chida J, Shikata K, Kido H. Thermal instability of compound variants of carnitine palmitoyltransferase II and impaired mitochondrial fuel utilization in influenza-associated encephalopathy. Hum Mutat 2008; 29:718-27. [PMID: 18306170 DOI: 10.1002/humu.20717] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Influenza-associated encephalopathy (IAE) is characterized by persistent high fever, febrile convulsions, severe brain edema, and high mortality in otherwise apparently healthy individuals. We have reported that a large proportion of patients suffering from disabling or fatal IAE, with transiently elevated serum acylcarnitine during high fever, exhibit a thermolabile phenotype of compound homo-/heterozygous variants of carnitine palmitoyltransferase II (CPT II, gene symbol CPT2). We characterized the enzymatic properties of five single and three compound CPT II variants in patients with IAE. The kinetic characteristics of WT and variant CPT IIs, expressed in COS-7 cells, indicated that the variants exert a dominant-negative effect on the homotetrameric protein of the enzyme. Among the variants, three compound variations found in patients with severe encephalopathy; [c.1055T>G (p.Phe352Cys); c.1102G>A (p.Val368Ile)], [c.1511C>T (p.Pro504Leu); c.1813G>C (p.Val605Leu)], and [c.1055T>G (p.Phe352Cys); c.1102G>A (p.Val368Ile); c.1813G>C (p.Val605Leu)], showed reduced activities, thermal instability, and short half-lives compared with the WT. Like other disease-causing mutant proteins, these variant proteins were poly-ubiquitinated and rapidly degraded by a lactacystin-sensitive proteasome pathway. COS-7 cells transfected with the compound variants had their fatty acid beta-oxidation decreased to 30-59% and intracellular ATP levels to 48-79%, and a marked reduction of mitochondrial membrane potential at 41 degrees C, compared with control cells transfected with WT at 37 degrees C. The unstable CPT II variants with decreased enzymatic activities may bring mitochondrial fuel utilization below the phenotypic threshold during high fever, and thus may play an important etiopathological role in the development of brain edema of IAE.
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Affiliation(s)
- Dengbing Yao
- Division of Enzyme Chemistry, Institute for Enzyme Research, The University of Tokushima, Tokushima, Japan
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21
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22
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Graf WD. Cerebral dysgeneses secondary to metabolic disorders in fetal life. HANDBOOK OF CLINICAL NEUROLOGY 2008; 87:459-476. [PMID: 18809039 DOI: 10.1016/s0072-9752(07)87025-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- William D Graf
- Section of Neurology, Children's Mercy Hospitals and Clinics and University of Missouri, 2401 Gillham Road, Kansas City, MO 64108, USA.
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23
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Angle B, Burton BK. Risk of sudden death and acute life-threatening events in patients with glutaric acidemia type II. Mol Genet Metab 2008; 93:36-9. [PMID: 17977044 DOI: 10.1016/j.ymgme.2007.09.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/20/2007] [Accepted: 09/20/2007] [Indexed: 01/29/2023]
Abstract
Glutaric acidemia type II (GAII) is an inborn error of metabolism caused by defects in electron transport flavoprotein (ETF) or ETF-ubiquinone oxidoreductase (ETF-QO) and typically presents with hypo- or nonketotic hypoglycemia and metabolic acidosis. The most severe forms present in early infancy and are associated with a high mortality rate. The disorder can now be detected by expanded newborn screening using tandem mass spectrometry (MS/MS), providing the opportunity for diagnosis and treatment in asymptomatic infants. We report here three infants who, despite diagnosis and treatment in the neonatal period, experienced either unexpected sudden death or an acute life-threatening event (ALTE) during the first year of life. The possible etiologies of these events and the potential impact of expanded newborn screening on the long-term outcome of GAII are discussed.
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Affiliation(s)
- Brad Angle
- Division of Birth Defects and Metabolism, Department of Pediatrics, Children's Memorial Hospital, Northwestern University, Feinberg School of Medicine, 2300 Children's Plaza, Chicago, IL 60614, USA.
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24
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Affiliation(s)
- Stefan Neubauer
- Department of Cardiovascular Medicine, University of Oxford and John Radcliffe Hospital, Oxford, United Kingdom.
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25
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Abstract
We investigated the effect of carnitine supplementation during vitamin C (ASC) deficiency by measuring the levels of ASC and carnitine in plasma and cardiac muscle cells (CMC), and histological analysis with electron microscopy. The levels of carnitine were significantly decreased in ASC-deficient rats in plasma and the heart than those in the control. In carnitine supplemented ASC-deficient rats, a significant increase of carnitine levels were observed in both plasma and heart. The number of lipid droplets significantly increased in the ASC-deficient rats compared to the control rats, but did not increase in carnitine supplemented rats. These results indicate that ASC deficiency causes a generalized mitochondrial abnormality and accumulation of lipid droplets in CMC as observed in carnitine deficiency, and supplementation of carnitine prevented these changes even in the presence of ASC deficiency.
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Affiliation(s)
- Maya Okamoto
- Department of Legal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
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26
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Vekemans BC, Bonnefont JP, Aupetit J, Royer G, Droin V, Attié-Bitach T, Saudubray JM, Thuillier L. Prenatal diagnosis of carnitine palmitoyltransferase 2 deficiency in chorionic villi: a novel approach. Prenat Diagn 2004; 23:884-7. [PMID: 14634971 DOI: 10.1002/pd.713] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Carnitine palmitoyltransferase 2 (CPT2) deficiency, the most common autosomal recessive inherited disease of the mitochondrial long-chain fatty acid (LCFA) beta-oxidation, may result in three distinct clinical phenotypes, namely, a mild adult muscular form, a severe infantile hepatocardiomuscular disease, and a neonatal form, which includes dysmorphic features in addition to hepatocardiomuscular symptoms. Both the latter forms are life-threatening diseases, and prenatal diagnosis (PND) can be offered to couples at a one-fourth risk of having an affected child. PND of CPT2 deficiency hitherto relied mostly on mutation detection from fresh chorionic villi (10 weeks' gestation), since CPT2 activity could be assayed on cultured amniocytes only (16-17 weeks' gestation).We devised a CPT2 activity assay from 10 mg of chorionic villi sampling (CVS). Combining this enzymatic assay to haplotype study using polymorphic markers linked to the CPT2 gene, we were able to carry out within 2 days, CPT2 deficiency PND, in two unrelated families, using a CVS performed at the 11th week of gestation.
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27
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Olpin SE. Implications of impaired ketogenesis in fatty acid oxidation disorders. Prostaglandins Leukot Essent Fatty Acids 2004; 70:293-308. [PMID: 14769488 DOI: 10.1016/j.plefa.2003.06.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2003] [Accepted: 06/01/2003] [Indexed: 01/09/2023]
Abstract
Long-chain fatty acids are important sources of respiratory fuel for many tissues and during fasting the rate of hepatic production of ketone bodies is markedly increased. Many extra hepatic tissues utilize ketone bodies in the fasted state with the advantage that glucose is "spared" for more vital tissues like the brain. This glucose sparing effect of ketones is especially important in infants where there is a high proportional glucose utilization in cerebral tissue. The first reported inherited defect affecting fatty acid oxidation was described in 1973 and to date about 15 separate disorders have been described. Although individually rare, cumulatively fatty acid oxidation defects are relatively common, have major consequences for affected individuals and their families, and carry significant health care implications. The major biochemical consequence of fatty acid oxidation defects is an inability of extra hepatic tissues to utilize fatty acids as an energy source with absent or limited hepatic capacity to generate ketones. Clinically patients usually present in infancy with acute life-threatening hypoketotic hypoglycaemia, liver disease, hyperammonaemia and cerebral oedema, with or without cardiac involvement, usually following a period of catabolic stress. Chronically there may be muscle involvement with hypotonia or exercise intolerance with or without cardiomyopathy. Treatment is generally by the avoidance of fasting, frequent carbohydrate rich feeds and for long-chain defects, the replacement of long-chain dietary fats with medium-chain formulae. Novel approaches to treatment include the use of d,l-3-hydoxybutyrate or heptanoate as an alternative energy source.
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Affiliation(s)
- Simon Edward Olpin
- Department of Clinical Chemistry, Sheffield Children's Hospital, Western Bank, Sheffield S10 2TH, UK
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28
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Sigauke E, Rakheja D, Kitson K, Bennett MJ. Carnitine palmitoyltransferase II deficiency: a clinical, biochemical, and molecular review. J Transl Med 2003; 83:1543-54. [PMID: 14615409 DOI: 10.1097/01.lab.0000098428.51765.83] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Congenital deficiency of carnitine palmitoyltransferase (CPT) II has been known for at least 30 years now, and its phenotypic variability remains fascinating. Three distinct clinical entities have been described, the adult, the infantile, and the perinatal, all with an autosomal recessive inheritance pattern. The adult CPT II clinical phenotype is somewhat benign and requires additional external triggers such as high-intensity exercise before the predominantly myopathic symptoms are elicited. The perinatal and infantile forms involve multiple organ systems. The perinatal disease is the most severe form and is invariably fatal. The introduction of mass spectrometry to analyze blood acylcarnitine profiles has revolutionized the diagnosis of fatty acid oxidation disorders including CPT II deficiency. Its use in expanded neonatal screening programs has made presymptomatic diagnosis a reality. An increasing number of mutations are being identified in the CPT II gene with a distinct genotype-phenotype correlation in most cases. However, clinical variability in some patients suggests additional genetic or environmental modifiers. Herein, we present a new case of lethal perinatal CPT II deficiency with a rare missense mutation, R296Q (907G>A) associated with a previously described 25-bp deletion on the second allele. We review the clinical features, the diagnostic protocol including expanded neonatal screening, the treatment, and the biochemical and molecular basis of CPT II deficiency.
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Affiliation(s)
- Ellen Sigauke
- Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
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29
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Bartlett K, Pourfarzam M. Defects of beta-oxidation including carnitine deficiency. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 53:469-516. [PMID: 12512350 DOI: 10.1016/s0074-7742(02)53017-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- K Bartlett
- Department of Child Health, Department of Clinical Biochemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 4LP, United Kingdom
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30
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Olpin SE, Afifi A, Clark S, Manning NJ, Bonham JR, Dalton A, Leonard JV, Land JM, Andresen BS, Morris AA, Muntoni F, Turnbull D, Pourfarzam M, Rahman S, Pollitt RJ. Mutation and biochemical analysis in carnitine palmitoyltransferase type II (CPT II) deficiency. J Inherit Metab Dis 2003; 26:543-57. [PMID: 14605500 DOI: 10.1023/a:1025947930752] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Carnitine palmitoyltransferase type II (CPT II) deficiency has three basic phenotypes, late-onset muscular (mild), infantile/juvenile hepatic (intermediate) and severe neonatal. We have measured fatty acid oxidation and CPT II activity and performed mutation studies in 24 symptomatic patients representing the full clinical spectrum of disease. Severe and intermediate phenotypes show a clear correlation with biochemical indices and genetic analysis revealed causative mutations in most patients. Studies of mild phenotypes suggest a more complex interaction, with higher residual fatty acid oxidation, a wider range of CPT II activity (10-60%) but little evidence of genotype-phenotype correlation. Residual CPT II mutant protein from myopathic patients shows thermal instability at 41 degrees C. The common 'polymorphisms' V3681 and M647V are strikingly overrepresented in the myopathic patients, the implication being that they may significantly influence the manifestation of clinical disease and could therefore potentially be considered as a susceptibility variants. Among myopathic individuals, males comprised 88% of patients, suggesting increased susceptibility to clinical disease. A small number of symptomatic patients appear to have significant residual CPT II activity (42-60%) The synergistic interaction of partial deficiencies of CPT II, muscle adenosine monophosphate deaminase and possibly other enzymes of muscle energy metabolism in the aetiology of episodic myopathy deserves wider consideration.
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Affiliation(s)
- S E Olpin
- Department of Clinical Chemistry, Sheffield Children's Hospital, UK
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31
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Abstract
PURPOSE OF REVIEW At least 22 different inborn errors of metabolism affecting beta-oxidation in skeletal muscle and other tissues have been identified in the past 30 years. Early diagnosis and therapeutic diets offer the best chance for normal growth and development in most patients. RECENT FINDINGS Clinical heterogeneity has become the hallmark of defects in beta-oxidation. In many cases a correct diagnosis will only be made if these disorders are specifically considered and appropriate studies are obtained, since screening tests which detect other inborn errors of metabolism are often normal in patients with beta-oxidation defects. Dietary management provides the only opportunity for therapy in many cases, including carbohydrate supplements intended to provide more extended delivery of glucose to the bloodstream. Use of a novel odd chain fat supplement as an alternative fuel source in long chain fat metabolism defects offers promise of alleviating muscular symptoms not well controlled by diet. The introduction of expanded newborn screening will lead to the recognition of an increasing number of individuals with these disorders, placing greater demand for services on practitioners knowledgeable in their therapy. Study of the clinical outcome in these patients will provide a better understanding of defects of beta-oxidation. SUMMARY Clinical symptoms, diagnostic testing, and issues of newborn screening for this important group of disorders are discussed.
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Affiliation(s)
- Jerry Vockley
- Department of Medical Genetics and Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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Giak Sim K, Carpenter K, Hammond J, Christodoulou J, Wilcken B. Quantitative fibroblast acylcarnitine profiles in mitochondrial fatty acid beta-oxidation defects: phenotype/metabolite correlations. Mol Genet Metab 2002; 76:327-34. [PMID: 12208138 DOI: 10.1016/s1096-7192(02)00112-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mitochondrial fatty acid beta-oxidation (FAO) disorders are clinically and biochemically heterogeneous diseases mainly associated with intolerance to catabolic stress. These disorders can now be detected pre-symptomatically by newborn screening, and thus the clinical phenotype in an individual patient may be unclear. Correlation of clinical severity with concentrations of acylcarnitine species was investigated in fibroblasts from FAO-deficient patients presenting with various phenotypes and asymptomatic neonates detected by newborn screening. Intact cells were incubated in medium containing deuterium-labelled hexadecanoic acid and L-carnitine for 72h, and the accumulated acylcarnitines in the culture medium analysed using electrospray tandem mass spectrometery. Fibroblasts from patients with long-chain FAO disorders presenting at an early age and with poor clinical outcomes accumulated higher concentrations of long-chain acylcarnitine species compared with those from patients with milder phenotypes. This suggests that the in vitro quantitative acylcarnitine profiling could perhaps predict the prognosis of some FAO defects. This would be particularly useful information for the asymptomatic/pre-symptomatic FAO-deficient infant detected by the expanded newborn screening program, in whom the risk of developing symptoms later in life is not known.
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Affiliation(s)
- Keow Giak Sim
- Department of Paediatrics and Child Health, University of Sydney, NSW, Australia
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Tsao CY, Mendell JR. Combined partial deficiencies of carnitine palmitoyltransferase II and mitochondrial complex I presenting as increased serum creatine kinase level. J Child Neurol 2002; 17:304-6. [PMID: 12088089 DOI: 10.1177/088307380201700414] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Increased serum creatine kinase level is a marker of neuromuscular disorders. When combined with exercise intolerance, muscle cramps, fatigue, myoglobinuria, or muscle weakness, metabolic myopathies of a variety of causes should be considered. We encountered an adolescent male with a persistently high serum creatine kinase level and chronic fatigue who was found to have combined partial defects of carnitine palmitoyltransferase II and mitochondrial complex I. Metabolic myopathy may present with chronic fatigue and a persistently high serum creatine kinase level but without muscle weakness and may be attributable to combined enzyme defects.
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Affiliation(s)
- Chang-Yong Tsao
- Department of Pediatrics and Neurology, College of Medicine and Public Health, The Ohio State University, Columbus, USA.
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34
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Rettinger A, Gempel K, Hofmann S, Gerbitz KD, Bauer MF. Tandem mass spectrometric assay for the determination of carnitine palmitoyltransferase II activity in muscle tissue. Anal Biochem 2002; 302:246-51. [PMID: 11878804 DOI: 10.1006/abio.2001.5554] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carnitine palmitoyltransferase II (CPT-II) mediates the import of long-chain fatty acids into the mitochondrial matrix for subsequent beta-oxidation. Defects of CPT-II manifest as a severe neonatal hepatocardiomuscular form or as a mild muscular phenotype in early infancy or adolescence. CPT-II deficiency is diagnosed by the determination of enzyme activity in tissues involving the time-dependent conversion of radiolabeled CPT-II substrates (isotope-exchange assays) or the formation of chromogenic reaction products. We have established a mass spectrometric assay (MS/MS) for the determination of CPT-II activity based on the stoichiometric formation of acetylcarnitine in a coupled reaction system. In this single-tube reaction system palmitoylcarnitine is converted by CPT-II to free carnitine, which is subsequently esterified to acetylcarnitine by carnitine acetyltransferase. The formation of acetylcarnitine directly correlates with the CPT-II activity. Comparison of the MS/MS method (y) with our routine spectrophotometric assay (x) revealed a linear regression of y = 0.58x + 0.12 (r = 0.8369). Both assays allow one to unambiguously detect patients with the muscular form of CPT-II deficiency. However, the higher specificity and sensitivity as well as the avoidance of the drawbacks inherent in the use of radiolabeled substrates make this mass spectrometric method most suitable for the determination of CPT-II activity.
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Affiliation(s)
- Armin Rettinger
- Institut für Klinische Chemie, Molekulare Diagnostik, und Mitochondriale Genetik und Institut für, Akademisches Lehrkrankenhaus München-Schwabing, Kölner Platz 1, Munich D-80804, Germany
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35
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Gempel K, Kiechl S, Hofmann S, Lochmüller H, Kiechl-Kohlendorfer U, Willeit J, Sperl W, Rettinger A, Bieger I, Pongratz D, Gerbitz KD, Bauer MF. Screening for carnitine palmitoyltransferase II deficiency by tandem mass spectrometry. J Inherit Metab Dis 2002; 25:17-27. [PMID: 11999976 DOI: 10.1023/a:1015109127986] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondrial carnitine palmitoyltransferase II (CPT II) deficiency is the most common inherited disorder of lipid metabolism in adults. Currently the routine diagnosis is based on the determination of CPT enzyme activity in muscle tissue. We have analysed the tandem mass spectra of serum acylcarnitines of nine CPT II-deficient patients. These spectra were compared to those of a cohort of 99 patients with other neuromuscular disorders and metabolic conditions supposed to cause alterations of the long-chain acylcarnitines. The spectra in CPT II deficiency showed characteristic elevations of C16:0 and C18:1 acylcarnitines while acetylcarnitine C2 was not elevated. In the present study, the ratio (C16:0+C18:1)/C2 has detected all CPT II deficiencies and discriminated them from unspecific alterations of serum acylcarnitines. The ratios of CPT II-deficient patients showed virtually no overlap with those observed in patients with other neuromuscular disorders. We suggest mass spectrometry of serum acylcarnitines as a rapid screening test that should be included early in the diagnostic work-up of patients with recurrent myoglobinuria, recurrent muscular weakness and myalgia.
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Affiliation(s)
- K Gempel
- Institute for Clinical Chemistry, Molecular Diagnostics and Mitochondrial Genetics and Munich Metabolic Disease Centre at the Academic Hospital Schwabing, Germany
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36
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Gregersen N, Andresen BS, Corydon MJ, Corydon TJ, Olsen RK, Bolund L, Bross P. Mutation analysis in mitochondrial fatty acid oxidation defects: Exemplified by acyl-CoA dehydrogenase deficiencies, with special focus on genotype-phenotype relationship. Hum Mutat 2001; 18:169-89. [PMID: 11524729 DOI: 10.1002/humu.1174] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mutation analysis of metabolic disorders, such as the fatty acid oxidation defects, offers an additional, and often superior, tool for specific diagnosis compared to traditional enzymatic assays. With the advancement of the structural part of the Human Genome Project and the creation of mutation databases, procedures for convenient and reliable genetic analyses are being developed. The most straightforward application of mutation analysis is to specific diagnoses in suspected patients, particularly in the context of family studies and for prenatal/preimplantation analysis. In addition, from these practical uses emerges the possibility to study genotype-phenotype relationships and investigate the molecular pathogenesis resulting from specific mutations or groups of mutations. In the present review we summarize current knowledge regarding genotype-phenotype relationships in three disorders of mitochondrial fatty acid oxidation: very-long chain acyl-CoA dehydrogenase (VLCAD, also ACADVL), medium-chain acyl-CoA dehydrogenase (MCAD, also ACADM), and short-chain acyl-CoA dehydrogenase (SCAD, also ACADS) deficiencies. On the basis of this knowledge we discuss current understanding of the structural implications of mutation type, as well as the modulating effect of the mitochondrial protein quality control systems, composed of molecular chaperones and intracellular proteases. We propose that the unraveling of the genetic and cellular determinants of the modulating effects of protein quality control systems may help to assess the balance between genetic and environmental factors in the clinical expression of a given mutation. The realization that the effect of the monogene, such as disease-causing mutations in the VLCAD, MCAD, and SCAD genes, may be modified by variations in other genes presages the need for profile analyses of additional genetic variations. The rapid development of mutation detection systems, such as the chip technologies, makes such profile analyses feasible. However, it remains to be seen to what extent mutation analysis will be used for diagnosis of fatty acid oxidation defects and other metabolic disorders.
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Affiliation(s)
- N Gregersen
- Research Unit for Molecular Medicine, Aarhus University Hospital and Faculty of Health Sciences, Aarhus, Denmark
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37
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Elpeleg ON, Hammerman C, Saada A, Shaag A, Golzand E, Hochner-Celnikier D, Berger I, Nadjari M. Antenatal presentation of carnitine palmitoyltransferase II deficiency. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 102:183-7. [PMID: 11477613 DOI: 10.1002/ajmg.1457] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Carnitine palmitoyl transferase (CPT) II deficiency is usually manifested around puberty by exercise induced myoglobinuria. Two Ashkenazi Jewish sibs with the rare antenatal form of CPTII deficiency are reported. On the 5th gestational month periventricular calcifications and markedly enlarged kidneys were found in both of them. The activity of CPTII in lymphocytes was undetectable and both sibs were homozygous for the 1237delAG mutation. Because of the serious consequences of homozygosity for this mutation, genotype determination of all Ashkenazi patients with the adolescent form of CPTII deficiency is warranted.
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Affiliation(s)
- O N Elpeleg
- Metabolic Disease Unit, Shaare-Zedek Medical Center, Jerusalem, Israel.
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38
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Albers S, Marsden D, Quackenbush E, Stark AR, Levy HL, Irons M. Detection of neonatal carnitine palmitoyltransferase II deficiency by expanded newborn screening with tandem mass spectrometry. Pediatrics 2001; 107:E103. [PMID: 11389301 DOI: 10.1542/peds.107.6.e103] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The introduction of tandem mass spectrometry to newborn screening has substantially expanded our ability to diagnose metabolic diseases in the newborn period. We report the first case of neonatal carnitine palmitoyltransferase deficiency II detected by expanded newborn screening with tandem mass spectrometry. The neonate presented with dysmorphic facial features, structural malformations, renal failure, seizures, and cardiac arrythmias and died on the third day of life. This experience illustrates the importance of expanded newborn screening to avoid missing a metabolic diagnosis in early infantile death.
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Affiliation(s)
- S Albers
- Division of Genetics, Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.
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39
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Guertl B, Noehammer C, Hoefler G. Metabolic cardiomyopathies. Int J Exp Pathol 2000; 81:349-72. [PMID: 11298185 PMCID: PMC2517748 DOI: 10.1046/j.1365-2613.2000.00186.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2001] [Accepted: 01/29/2001] [Indexed: 01/27/2023] Open
Abstract
The energy needed by cardiac muscle to maintain proper function is supplied by adenosine Ariphosphate primarily (ATP) production through breakdown of fatty acids. Metabolic cardiomyopathies can be caused by disturbances in metabolism, for example diabetes mellitus, hypertrophy and heart failure or alcoholic cardiomyopathy. Deficiency in enzymes of the mitochondrial beta-oxidation show a varying degree of cardiac manifestation. Aberrations of mitochondrial DNA lead to a wide variety of cardiac disorders, without any obvious correlation between genotype and phenotype. A completely different pathogenetic model comprises cardiac manifestation of systemic metabolic diseases caused by deficiencies of various enzymes in a variety of metabolic pathways. Examples of these disorders are glycogen storage diseases (e.g. glycogenosis type II and III), lysosomal storage diseases (e.g. Niemann-Pick disease, Gaucher disease, I-cell disease, various types of mucopolysaccharidoses, GM1 gangliosidosis, galactosialidosis, carbohydrate-deficient glycoprotein syndromes and Sandhoff's disease). There are some systemic diseases which can also affect the heart, for example triosephosphate isomerase deficiency, hereditary haemochromatosis, CD 36 defect or propionic acidaemia.
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Affiliation(s)
- B Guertl
- Institute of Pathology, University of Graz, Austria.
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40
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Abstract
The most common form of carnitine palmitoyltransferase II (CPT II) deficiency occurs in adults and is characterized by muscle pain, stiffness, and myoglobinuria, triggered by exercise, fasting, or other metabolic stress. This study reports the molecular heterogeneity of CPT2 mutations and their biochemical consequences among a series of 59 individuals who were suspected of having CPT II deficiency based on the decreased CPT activity observed in muscle or leukocytes samples, clinical findings, or referral for mutation analysis from other laboratories. Only 19 subjects were considered to be at particularly high risk of CPT II deficiency based on review of their clinical symptoms and residual CPT activity. The samples were initially screened for 11 mutations with allele-specific oligonucleotides (ASO). Extensive sequence analysis was subsequently performed on 14 samples which either had a CPT2 mutation detected by ASO screening or the residual CPT activity was below that observed in ASO positive samples. Three known (P50H, S113L, and F448L) and three novel mutations were identified among 13 individuals in this study. A single nucleotide polymorphism was also identified 11 bp distal to the CPT2 polyadenylation site that will be useful for linkage analysis. Two of the new mutations were single nucleotide missense mutations, R503C and G549D, that occurred in highly conserved regions of the CPT isoforms, and the third was a frameshift mutation, 413 delAG, caused by a 2-bp deletion upstream of a previously identified missense mutation, F448L. The 413 delAG mutation was the second most common mutation identified in our study (20% of mutant alleles) and all individuals with the mutation were of Ashkenazi Jewish ancestry suggesting a defined ethnic origin for the mutation. Despite rigorous mutation analysis, six of 13 individuals identified with CPT2 mutations remained as heterozygotes. We propose that heterozygosity for certain CPT2 mutations, S113L and R503C, is sufficient to render individuals at risk of clinical symptoms.
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Affiliation(s)
- R T Taggart
- Department of Pediatrics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, USA
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41
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Wataya K, Akanuma J, Cavadini P, Aoki Y, Kure S, Invernizzi F, Yoshida I, Kira J, Taroni F, Matsubara Y, Narisawa K. Two CPT2 mutations in three Japanese patients with carnitine palmitoyltransferase II deficiency: functional analysis and association with polymorphic haplotypes and two clinical phenotypes. Hum Mutat 2000; 11:377-86. [PMID: 9600456 DOI: 10.1002/(sici)1098-1004(1998)11:5<377::aid-humu5>3.0.co;2-e] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Carnitine palmitoyltransferase II (CPT II) deficiency manifests as two different clinical phenotypes: a muscular form and a hepatic form. We have investigated three nonconsanguineous Japanese patients with CPT II deficiency. Molecular analysis revealed two missense mutations, a glutamate (174)-to-lysine substitution (E174K) and a phenylalanine (383)-to-tyrosine substitution (F383Y) in the CPT II cDNA. Transfection experiments in COS-1 cells demonstrated that the two mutations markedly decreased the catalytic activity of mutant CPT II. Case 1 (hepatic form) was homozygous for the F383Y mutation, whereas case 3 (muscular form) was homozygous for the E174K mutation. Case 2 and her brother, who were compound heterozygotes for E174K and F383Y, exhibited the hepatic phenotype. We also identified a novel polymorphism in the CPT2 gene, a phenylalanine (352)-to-cysteine substitution (F352C), which did not alter CPT II activity in transfected cells. It was present in 21 out of 100 normal alleles in the Japanese population, but absent in Caucasian populations. Genotyping with the F352C polymorphism and the two previously reported polymorphisms, V368I and M647V, allowed normal Japanese alleles to be classified into five haplotypes. In all three families with CPT II deficiency, the E174K mutation resided only on the F1V1M1 allele, whereas the F383Y mutation was observed on the F2V2M1 allele, suggesting a single origin for each mutation.
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Affiliation(s)
- K Wataya
- Department of Biochemical Genetics, Tohoku University School of Medicine, Sendai, Japan
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42
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Bruno C, Bado M, Minetti C, Cordone G, DiMauro S. Novel mutation in the CPT II gene in a child with periodic febrile myalgia and myoglobinuria. J Child Neurol 2000; 15:390-3. [PMID: 10868782 DOI: 10.1177/088307380001500607] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have identified a novel missense mutation in the carnitine palmitoyltransferase II (CPT II) gene in a child with CPT II deficiency characterized clinically by episodes of myalgia and myoglobinuria induced by intercurrent febrile illnesses. The patient was heterozygous for a G-to-A substitution at codon 487, changing an encoded glutamic acid to a lysine (E489K), while the other allele carried the common S113L mutation. This case enlarges the spectrum of mutations in patients with CPT II deficiency, and confirms the association of the S113L mutation with the muscular form.
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Affiliation(s)
- C Bruno
- Department of Pediatrics, University of Genova, Istituto Giannina Gaslini, Italy
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43
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Wieser T, Deschauer M, Zierz S. Genetics of carnitine palmitoyltransferase II deficiencies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:339-45. [PMID: 10709661 DOI: 10.1007/0-306-46818-2_39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- T Wieser
- Klinik und Poliklinik für Neurologie, Martin-Luther-Universität Halle/Wittenberg, Halle/S., Germany.
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44
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van der Leij FR, Drijfholt A, Kuipers JR. Rationale for a conditional knockout mouse model to study carnitine palmitoyltransferase I deficiencies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:377-85. [PMID: 10709666 DOI: 10.1007/0-306-46818-2_44] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Several severe congenital cardiomyopathies are known to be associated with deficiencies in long-chain fatty acid transport and oxidation. Our studies are focused on a key enzyme in the regulation of intracellular long-chain fatty acid transport: carnitine palmitoyltransferase 1. Of this enzyme, two isoforms are expressed in the neonatal heart: L-CPT1 (the "liver-type" isoform) and M-CPT1 (the "muscle-type" isoform). It is known from studies in rats that chemical inhibition of both CPT1 isoforms results in hypertrophy of the cardiomyocytes, leading to an increase in heart-weight of up to 25%. With the aid of expressed sequence tag database analyses, cDNA- and genomic sequence information, we analysed the human gene for M-CPT1 in detail, and obtained partial clones of the murine genes for both CPT1 isoforms. We now started the development of a conditional knockout model to analyse and dissect deficiencies in these genes. While of the other mitochondrial components of the carnitine system deficiencies are known, some with severe cardiac consequences, M-CPT1 deficiencies have never been described. This suggests that M-CPT1 deficiency either (1) has not been recognised within the pool of congenital disorders, (2) is detrimental in an early stage of reproduction or embryogenesis, or (3) does not lead to physiological problems, probably due to the existence of a rescue system. If (1) is the case, the phenotypic effects of M-CPT1 deficiency have to be studied in order to generate criteria for clinical decision making and diagnosis. Option (2) demonstrates the necessity to use novel vector systems to create conditional gene disruptions. Hypothesis (3) implies a possible role for L-CPT1, and a knockout model allows a study of the interaction between the genes for L-CPT1 and M-CPT1. Applicable strategies to develop such a model system will be discussed.
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Affiliation(s)
- F R van der Leij
- Department of Pediatrics, Groningen Utrecht Institute for Drug Exploration, University of Groningen, The Netherlands.
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45
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Thuillier L, Sevin C, Demaugre F, Brivet M, Rabier D, Droin V, Aupetit J, Abadi N, Kamoun P, Saudubray JM, Bonnefont JP. Genotype/phenotype correlation in carnitine palmitoyl transferase II deficiency: lessons from a compound heterozygous patient. Neuromuscul Disord 2000; 10:200-5. [PMID: 10734268 DOI: 10.1016/s0960-8966(99)00096-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Carnitine palmitoyl transferase II deficiency, an inherited disorder of long-chain fatty acid oxidation, may result in either a mild form (muscle disease in adults) or a severe form (hepatocardiomuscular syndrome in infants). The difference in severity between these two forms is related to a difference in levels of residual carnitine palmitoyl transferase II activity and long-chain fatty acid oxidation and in genotypes. Few data are, however, available regarding compound heterozygotes for a 'mild' and a 'severe' carnitine palmitoyl transferase II mutation. We report on such a patient carrying both the 'mild' S113L substitution and the 'severe' Y628S mutation. The patient's clinical picture (cardiac arrest at 6 years) was markedly more serious than usually observed in S113L homozygotes, and suggested that 'mild'/'severe' compound heterozygosity makes patients at risk from life-threatening events. Palmitate oxidation and carnitine palmitoyl transferase II activity were lower in lymphocytes from the S113L/Y628S patient than in those from a S113L homozygote. Thus, assessment of carnitine palmitoyl transferase II mutations, long-chain fatty acid oxidation, and carnitine palmitoyl transferase II activity, may help in predicting the potential severity of the muscular form of carnitine palmitoyl transferase II deficiency.
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Affiliation(s)
- L Thuillier
- Laboratoire de Biochimie Génétique, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, F-75743, Paris, France
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46
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Abstract
Major recent advances in the field of metabolic myopathies have helped delineate the genetic and biochemical basis of these disorders. This progress has also resulted in the development of new diagnostic and therapeutic methodologies. In this second part, we present an updated review of the main nonlysosomal and lysosomal glycogenoses and lipid metabolism defects that manifest with signs of transient or permanent muscle dysfunction. Our intent is to increase the pediatric neurologist's familiarity with these conditions and thus improve decision making in the areas of diagnosis and treatment.
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Affiliation(s)
- B T Darras
- Neuromuscular Program, Department of Neurology, Children's Hospital, Harvard Medical School, Massachusetts, USA
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47
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Hurvitz H, Klar A, Korn-Lubetzki I, Wanders RJ, Elpeleg ON. Muscular carnitine palmitoyltransferase II deficiency in infancy. Pediatr Neurol 2000; 22:148-50. [PMID: 10738923 DOI: 10.1016/s0887-8994(99)00125-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An 8-month-old female presented with febrile myoglobinuria. The activity of carnitine palmitoyltransferase (CPT) II was decreased to 16% of the control mean, and the oxidation of the long-chain fatty acids was reduced to 25% of the mean in the fibroblasts. Homozygosity for the common mutation, S113L, was identified in the CPT II gene. Residual CPT II activity of more than 10% of the mean and homozygosity for the common mutation S113L are usually associated with a milder reduction of long-chain fatty acid oxidation to about 80% of the control and with a later age of clinical onset. The early clinical presentation in the present patient is unique and was associated with a marked impairment of long-chain fatty acid oxidation, possibly because of other genetic factors. CPT II deficiency should be included in the differential diagnosis of isolated myoglobinuria in infancy.
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Affiliation(s)
- H Hurvitz
- Department of Pediatrics, Bikur Cholim General Hospital, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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48
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Abstract
Lipid storage myopathies are typically present with recurrent episodes of myoglobinuria and hypoglycemia, triggered by fasting or infection. Dilated cardiomyopathy can occur. This article will discuss an approach to lipid storage myopathies and describes various forms of disorders by fatty acid oxidation.
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Affiliation(s)
- V A Cwik
- Department of Neurology, The University of Arizona Health Sciences Center, Tucson, AZ 85724, USA
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49
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Abstract
Inborn errors of the mitochondrial beta-oxidation of long-chain fatty acids represent an evolving field of inherited metabolic disease. Fatty acid oxidation defects demonstrate an abnormal response to the process of fasting adaptation and affect those tissues that utilize fatty acids as an energy source. These tissues include cardiac and skeletal muscle and liver. Muscle directly uses fatty acids as an energy source whilst hepatic metabolism of fatty acids is mostly directed toward the synthesis of ketone bodies for energy utilization by tissues such as brain. The clinical phenotypes of fatty acid oxidation disorders include disease of one or more of these fatty acid-metabolizing tissues. In this review, we provide an overview of the pathway, discuss the disorders that are well established, and describe recent advances in the field. Currently available diagnostic procedures are critically evaluated.
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Affiliation(s)
- M J Bennett
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas 75235, USA.
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50
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Bonnefont JP, Demaugre F, Prip-Buus C, Saudubray JM, Brivet M, Abadi N, Thuillier L. Carnitine palmitoyltransferase deficiencies. Mol Genet Metab 1999; 68:424-40. [PMID: 10607472 DOI: 10.1006/mgme.1999.2938] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carnitine palmitoyltransferase (CPT) deficiencies are common disorders of mitochondrial fatty acid oxidation. The CPT system is made up of two separate proteins located in the outer- (CPT1) and inner- (CPT2) mitochondrial membranes. While CPT2 is a ubiquitous protein, two tissue-specific CPT1 isoforms-the so-called "liver" (L) and "muscle" (M) CPT1s-have been shown to exist. Amino acid and cDNA nucleotide sequences have been identified for all of these proteins. L-CPT1 deficiency (13 families reported) presents as recurrent attacks of fasting hypoketotic hypoglycemia. Two L-CPT1 mutations have been reported to date. M-CPT1 deficiency has not been hitherto identified. CPT2 deficiency has several clinical presentations. The "benign" adult form (more than 150 families reported) is characterized by episodes of rhabdomyolysis triggered by prolonged exercise. The prevalent S113L mutation is found in about 50% of mutant alleles. The infantile-type CPT2 deficiency (10 families reported) presents as severe attacks of hypoketotic hypoglycemia, occasionally associated with cardiac damage commonly responsible for sudden death before 1 year of age. In addition to these symptoms, features of brain and kidney dysorganogenesis are frequently seen in the neonatal-onset CPT2 deficiency (13 families reported), almost always lethal during the first month of life. More than 25 CPT2 mutations (private missense or truncating mutations) have hitherto been detected. Treatment is based upon avoidance of fasting and/or exercise, a low-fat diet enriched with medium chain triglycerides and carnitine ("severe" CPT2 deficiency). Prenatal diagnosis may be offered for pregnancies at a 1/4 risk of infantile/severe-type CPT2 deficiency.
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Affiliation(s)
- J P Bonnefont
- Genetic Biochemistry Unit, CHU Necker-Enfants Malades, Paris, France.
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