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Vianey-Saban C, Guffon N, Fouilhoux A, Acquaviva C. Fifty years of research on mitochondrial fatty acid oxidation disorders: The remaining challenges. J Inherit Metab Dis 2023; 46:848-873. [PMID: 37530674 DOI: 10.1002/jimd.12664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/19/2023] [Accepted: 07/26/2023] [Indexed: 08/03/2023]
Abstract
Since the identification of the first disorder of mitochondrial fatty acid oxidation defects (FAOD) in 1973, more than 20 defects have been identified. Although there are some differences, most FAOD have similar clinical signs, which are mainly due to energy depletion and toxicity of accumulated metabolites. However, some of them have an unusual clinical phenotype or specific clinical signs. This manuscript focuses on what we have learnt so far on the pathophysiology of these disorders, which present with clinical signs that are not typical of categorical FAOD. It also highlights that some disorders have not yet been identified and tries to make assumptions to explain why. It also deals with new treatments under consideration in FAOD, including triheptanoin and similar anaplerotic substrates, ketone body treatments, RNA and gene therapy approaches. Finally, it suggests challenges for the diagnosis of FAOD in the coming years, both for symptomatic patients and for those diagnosed through newborn screening. The ultimate goal would be to identify all the patients born with FAOD and ensure for them the best possible quality of life.
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Affiliation(s)
- Christine Vianey-Saban
- Biochemical and Molecular Biology Laboratory, Metabolic Inborn Errors of Metabolism Unit, Groupement Hospitalier Est, CHU de Lyon, Bron, France
| | - Nathalie Guffon
- National Reference Centre for Hereditary Metabolic Diseases, Groupement Hospitalier Est, CHU de Lyon, Bron, France
| | - Alain Fouilhoux
- National Reference Centre for Hereditary Metabolic Diseases, Groupement Hospitalier Est, CHU de Lyon, Bron, France
| | - Cécile Acquaviva
- Biochemical and Molecular Biology Laboratory, Metabolic Inborn Errors of Metabolism Unit, Groupement Hospitalier Est, CHU de Lyon, Bron, France
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2
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Mizuguchi M, Shibata A, Kasai M, Hoshino A. Genetic and environmental risk factors of acute infection-triggered encephalopathy. Front Neurosci 2023; 17:1119708. [PMID: 36761411 PMCID: PMC9902370 DOI: 10.3389/fnins.2023.1119708] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/09/2023] [Indexed: 01/25/2023] Open
Abstract
Acute encephalopathy is a constellation of syndromes in which immune response, metabolism and neuronal excitation are affected in a variable fashion. Most of the syndromes are complex disorders, caused or aggravated by multiple, genetic and environmental risk factors. Environmental factors include pathogenic microorganisms of the antecedent infection such as influenza virus, human herpesvirus-6 and enterohemorrhagic Escherichia coli, and drugs such as non-steroidal anti-inflammatory drugs, valproate and theophylline. Genetic factors include mutations such as rare variants of the SCN1A and RANBP2 genes, and polymorphisms such as thermolabile CPT2 variants and HLA genotypes. By altering immune response, metabolism or neuronal excitation, these factors complicate the pathologic process. On the other hand, some of them could provide promising targets to prevent or treat acute encephalopathy.
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Affiliation(s)
- Masashi Mizuguchi
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Department of Pediatrics, National Rehabilitation Center for Children With Disabilities, Tokyo, Japan,*Correspondence: Masashi Mizuguchi,
| | - Akiko Shibata
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Laboratory for Brain Development and Disorders, RIKEN Center for Brain Science, Tokyo, Japan
| | - Mariko Kasai
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Department of Pediatrics, Saitama Citizens Medical Center, Saitama, Japan
| | - Ai Hoshino
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Fuchu, Japan
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3
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Ruiz-Sala P, Peña-Quintana L. Biochemical Markers for the Diagnosis of Mitochondrial Fatty Acid Oxidation Diseases. J Clin Med 2021; 10:jcm10214855. [PMID: 34768374 PMCID: PMC8584803 DOI: 10.3390/jcm10214855] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/07/2021] [Accepted: 10/19/2021] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial fatty acid β-oxidation (FAO) contributes a large proportion to the body’s energy needs in fasting and in situations of metabolic stress. Most tissues use energy from fatty acids, particularly the heart, skeletal muscle and the liver. In the brain, ketone bodies formed from FAO in the liver are used as the main source of energy. The mitochondrial fatty acid oxidation disorders (FAODs), which include the carnitine system defects, constitute a group of diseases with several types and subtypes and with variable clinical spectrum and prognosis, from paucisymptomatic cases to more severe affectations, with a 5% rate of sudden death in childhood, and with fasting hypoketotic hypoglycemia frequently occurring. The implementation of newborn screening programs has resulted in new challenges in diagnosis, with the detection of new phenotypes as well as carriers and false positive cases. In this article, a review of the biochemical markers used for the diagnosis of FAODs is presented. The analysis of acylcarnitines by MS/MS contributes to improving the biochemical diagnosis, both in affected patients and in newborn screening, but acylglycines, organic acids, and other metabolites are also reported. Moreover, this review recommends caution, and outlines the differences in the interpretation of the biomarkers depending on age, clinical situation and types of samples or techniques.
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Affiliation(s)
- Pedro Ruiz-Sala
- Centro de Diagnóstico de Enfermedades Moleculares, Universidad Autónoma Madrid, CIBERER, IDIPAZ, 28049 Madrid, Spain;
| | - Luis Peña-Quintana
- Pediatric Gastroenterology, Hepatology and Nutrition Unit, Mother and Child Insular University Hospital Complex, Asociación Canaria para la Investigación Pediátrica (ACIP), CIBEROBN, University Institute for Research in Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, 35016 Las Palmas de Gran Canaria, Spain
- Correspondence:
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Knottnerus SJG, Bleeker JC, Wüst RCI, Ferdinandusse S, IJlst L, Wijburg FA, Wanders RJA, Visser G, Houtkooper RH. Disorders of mitochondrial long-chain fatty acid oxidation and the carnitine shuttle. Rev Endocr Metab Disord 2018; 19:93-106. [PMID: 29926323 PMCID: PMC6208583 DOI: 10.1007/s11154-018-9448-1] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial fatty acid oxidation is an essential pathway for energy production, especially during prolonged fasting and sub-maximal exercise. Long-chain fatty acids are the most abundant fatty acids in the human diet and in body stores, and more than 15 enzymes are involved in long-chain fatty acid oxidation. Pathogenic mutations in genes encoding these enzymes result in a long-chain fatty acid oxidation disorder in which the energy homeostasis is compromised and long-chain acylcarnitines accumulate. Symptoms arise or exacerbate during catabolic situations, such as fasting, illness and (endurance) exercise. The clinical spectrum is very heterogeneous, ranging from hypoketotic hypoglycemia, liver dysfunction, rhabdomyolysis, cardiomyopathy and early demise. With the introduction of several of the long-chain fatty acid oxidation disorders (lcFAOD) in newborn screening panels, also asymptomatic individuals with a lcFAOD are identified. However, despite early diagnosis and dietary therapy, a significant number of patients still develop symptoms emphasizing the need for individualized treatment strategies. This review aims to function as a comprehensive reference for clinical and laboratory findings for clinicians who are confronted with pediatric and adult patients with a possible diagnosis of a lcFAOD.
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Affiliation(s)
- Suzan J G Knottnerus
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Jeannette C Bleeker
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Rob C I Wüst
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Lodewijk IJlst
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Frits A Wijburg
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Gepke Visser
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands.
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
| | - Riekelt H Houtkooper
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
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Study of Carnitine/Acylcarnitine and Amino Acid Profile in Children and Adults With Acute Liver Failure. J Pediatr Gastroenterol Nutr 2017; 64:869-875. [PMID: 28045774 DOI: 10.1097/mpg.0000000000001510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Fatty acid oxidation defects (FAODs) may underlie or modify the course of acute liver failure (ALF). Overall significance of carnitine/acylcarnitine and amino acid profile in ALF is similarly undetermined. Thus, this study was undertaken to study the abnormalities in carnitine/acylcarnitine and amino acid profile in ALF. METHODS A prospective study was performed including all patients with ALF, and detailed evaluation including metabolic testing was done. RESULTS A total of 55 patients (33 pediatric and 22 adult patients) were included in the study. Three patients (a 1-year 6-month-old child, a 13-year-old adolescent, and a 21-year-old adult, ie, 5.5% of all) were identified for the study with underlying metabolic etiology, that is, carnitine palmitoyl transferase-1 deficiency, based on the abnormal carnitine/acylcarnitine profile. Almost three-fourths of patients (78%) had evidence of serum hyperaminoacidemia. Thirty-one patients (56%) had evidence of abnormal carnitine/acylcarnitine profile with predominant abnormality being low free carnitine (C0). Higher levels of serum tyrosine (P = 0.002) and lower levels of serum C0 (P = 0.032) in children and higher levels of serum phenyalanine (P = 0.047) in adults predicted poor outcome (death/liver transplant) on univariate analysis. CONCLUSIONS FAODs are not uncommon in ALF with a suggested prevalence of approximately 5.5%. FAODs can cause ALF or modify the natural course of ALF caused by other etiologies. Serum hyperaminoacidemia and low serum free carnitine may predict poor outcome in patients with acute liver failure.
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Fontaine M, Dessein AF, Douillard C, Dobbelaere D, Brivet M, Boutron A, Zater M, Mention-Mulliez K, Martin-Ponthieu A, Vianey-Saban C, Briand G, Porchet N, Vamecq J. A Novel Mutation in CPT1A Resulting in Hepatic CPT Deficiency. JIMD Rep 2012; 6:7-14. [PMID: 23430932 DOI: 10.1007/8904_2011_94] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/14/2011] [Accepted: 09/16/2011] [Indexed: 11/26/2022] Open
Abstract
The present work presents a "from gene defect to clinics" pathogenesis study of a patient with a hitherto unreported mutation in the CPT1A gene. In early childhood, the patient developed a life-threatening episode (hypoketotic hypoglycemia, liver cytolysis, and hepatomegaly) evocative of a mitochondrial fatty acid oxidation disorder, and presented deficient fibroblast carnitine palmitoyltransferase 1 (CPT1) activity and homozygosity for the c.1783 C > T nucleotide substitution on exon 15 of CPT1A (p.R595W mutant). While confirming CPT1A deficiency, whole blood de novo acylcarnitine synthesis and the levels of carnitine and its esters formally linked intracellular free-carnitine depletion to intracellular carnitine esterification. Sequence alignment and modeling of wild-type and p.*R595W CPT1A proteins indicated that the Arg595 targeted by the mutated codon is phylogenetically well conversed. It contributes to a hydrogen bond network with neighboring residues Cys304 and Met593 but does not participate in the catalysis and carnitine pocket. Its replacement by tryptophan induces steric hindrance with the side chain of Ile480 located in α-helix 12, affecting protein architecture and function. This hindrance with Ile480 is also originally described with tryptophan 304 in the known mutant p.C304W CPT1A, suggesting that the mechanisms that invalidate CPT1A activity and underlie pathogenesis could be common in both the new (p.R595W) and previously described (p.C304W) mutants.
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Affiliation(s)
- Monique Fontaine
- Laboratory of Hormonology, Metabolism-Nutrition & Oncology (HMNO), Center of Biology and Pathology, CHRU Lille, 59037, Lille, France
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7
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Dessein AF, Fontaine M, Andresen BS, Gregersen N, Brivet M, Rabier D, Napuri-Gouel S, Dobbelaere D, Mention-Mulliez K, Martin-Ponthieu A, Briand G, Millington DS, Vianey-Saban C, Wanders RJA, Vamecq J. A novel mutation of the ACADM gene (c.145C>G) associated with the common c.985A>G mutation on the other ACADM allele causes mild MCAD deficiency: a case report. Orphanet J Rare Dis 2010; 5:26. [PMID: 20923556 PMCID: PMC2967532 DOI: 10.1186/1750-1172-5-26] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 10/05/2010] [Indexed: 12/31/2022] Open
Abstract
A female patient, with normal familial history, developed at the age of 30 months an episode of diarrhoea, vomiting and lethargy which resolved spontaneously. At the age of 3 years, the patient re-iterated vomiting, was sub-febrile and hypoglycemic, fell into coma, developed seizures and sequels involving right hemi-body. Urinary excretion of hexanoylglycine and suberylglycine was low during this metabolic decompensation. A study of pre- and post-prandial blood glucose and ketones over a period of 24 hours showed a normal glycaemic cycle but a failure to form ketones after 12 hours fasting, suggesting a mitochondrial β-oxidation defect. Total blood carnitine was lowered with unesterified carnitine being half of the lowest control value. A diagnosis of mild MCAD deficiency (MCADD) was based on rates of 1-14C-octanoate and 9, 10-3H-myristate oxidation and of octanoyl-CoA dehydrogenase being reduced to 25% of control values. Other mitochondrial fatty acid oxidation proteins were functionally normal. De novo acylcarnitine synthesis in whole blood samples incubated with deuterated palmitate was also typical of MCADD. Genetic studies showed that the patient was compound heterozygous with a sequence variation in both of the two ACADM alleles; one had the common c.985A>G mutation and the other had a novel c.145C>G mutation. This is the first report for the ACADM gene c.145C>G mutation: it is located in exon 3 and causes a replacement of glutamine to glutamate at position 24 of the mature protein (Q24E). Associated with heterozygosity for c.985A>G mutation, this mutation is responsible for a mild MCADD phenotype along with a clinical story corroborating the emerging literature view that patients with genotypes representing mild MCADD (high residual enzyme activity and low urinary levels of glycine conjugates), similar to some of the mild MCADDs detected by MS/MS newborn screening, may be at risk for disease presentation.
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Affiliation(s)
- Anne-Frédérique Dessein
- Department of Biochemistry and Molecular Biology, Laboratory of Hormonology, Metabolism-Nutrition & Oncology, Center of Biology and Pathology Pierre-Marie Degand, CHRU Lille, 59037 Lille, France
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8
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Diagnostic assessment and long-term follow-up of 13 patients with Very Long-Chain Acyl-Coenzyme A dehydrogenase (VLCAD) deficiency. Neuromuscul Disord 2009; 19:324-9. [PMID: 19327992 DOI: 10.1016/j.nmd.2009.02.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 02/03/2009] [Accepted: 02/13/2009] [Indexed: 11/23/2022]
Abstract
Very Long-Chain Acyl-CoA dehydrogenase (VLCAD) deficiency is an inborn error of mitochondrial long-chain fatty acid oxidation (FAO) most often occurring in childhood with cardiac or liver involvement, but rhabdomyolysis attacks have also been reported in adults. We report in this study the clinical, biochemical and molecular studies in 13 adult patients from 10 different families with VLCAD deficiency. The enzyme defect was demonstrated in cultured skin fibroblasts or lymphocytes. All patients exhibited exercise intolerance and recurrent rhabdomyolysis episodes, which were generally triggered by strenuous exercise, fasting, cold or fever (mean age at onset: 10 years). Inaugural life-threatening general manifestations also occurred before the age of 3 years in four patients. Increased levels of long-chain acylcarnitines with tetradecenoylcarnitine (C14:1) as the most prominent species were observed in all patients. Muscle biopsies showed a mild lipidosis in four patients. For all patients but two, molecular analysis showed homozygous (4 patients) or compound heterozygous genotype (7 patients). For the two remaining patients, only one mutation in a heterozygous state was detected. This study confirms that VLCAD deficiency, although being less frequent than CPT II deficiency, should be systematically considered in the differential diagnosis of exercise-induced rhabdomyolysis. Measurement of fasting blood acylcarnitines by tandem mass spectrometry allows accurate biochemical diagnosis and should therefore be performed in all patients presenting with unexplained muscle exercise intolerance or rhabdomyolysis.
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Abstract
Nonalcoholic fatty liver disease (NAFLD) is a group of diseases with excess fat in liver in the absence of a poorly defined limit of alcohol consumption. Most common variety, a universal public health problem, is associated with insulin resistance caused by a host of genetic and epigenetic defects modulated by life style and environmental factors. In fact the term NAFLD is loose to incorporate so many etiologies except alcoholism and few other etiologies, presenting as fat in liver. However as a sign fatty liver is very important in predicting the risk of diabetes, cardiovascular disease, stroke, cirrhosis and cancer. Abnormal fat accumulation can result from several defects in nuclear receptors associated with lipid sensing, synthesis and oxidation like LXR, FXR, SREBP, ChREBP and PPAR; defects in the lipid influx-efflux channels, insulin signaling, proteins involved in fatty acid catabolism, defects in adipose tissue development and function, inappropriate nutrition and finally defects in neural regulatory mechanisms. The progress of the disease is determined by the basic defects which results in fat accumulation, an individual’s immunological response to the accumulated fat and its derivatives and the oxidant stress response. Congregation of unrelated genetic defects under same diagnosis ‘NAFLD’ can result in inefficient patient management. Further studies are required to understand the molecular basis of fatty liver to enable a personalized management of diseases presenting as fatty liver in the absence of alcohol abuse.
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Sharma S, Sud N, Wiseman DA, Carter AL, Kumar S, Hou Y, Rau T, Wilham J, Harmon C, Oishi P, Fineman JR, Black SM. Altered carnitine homeostasis is associated with decreased mitochondrial function and altered nitric oxide signaling in lambs with pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2007; 294:L46-56. [PMID: 18024721 DOI: 10.1152/ajplung.00247.2007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Utilizing aortopulmonary vascular graft placement in the fetal lamb, we have developed a model (shunt) of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. Our previous studies have identified a progressive development of endothelial dysfunction in shunt lambs that is dependent, at least in part, on decreased nitric oxide (NO) signaling. The purpose of this study was to evaluate the possible role of a disruption in carnitine metabolism in shunt lambs and to determine the effect on NO signaling. Our data indicate that at 2 wk of age, shunt lambs have significantly reduced expression (P < 0.05) of the key enzymes in carnitine metabolism: carnitine palmitoyltransferases 1 and 2 as well as carnitine acetyltransferase (CrAT). In addition, we found that CrAT activity was inhibited due to increased nitration. Furthermore, free carnitine levels were significantly decreased whereas acylcarnitine levels were significantly higher in shunt lambs (P < 0.05). We also found that alterations in carnitine metabolism resulted in mitochondrial dysfunction, since shunt lambs had significantly decreased pyruvate, increased lactate, and a reduced pyruvate/lactate ratio. In pulmonary arterial endothelial cells cultured from juvenile lambs, we found that mild uncoupling of the mitochondria led to a decrease in cellular ATP levels and a reduction in both endothelial NO synthase-heat shock protein 90 (eNOS-HSP90) interactions and NO signaling. Similarly, in shunt lambs we found a loss of eNOS-HSP90 interactions that correlated with a progressive decrease in NO signaling. Our data suggest that mitochondrial dysfunction may play a role in the development of endothelial dysfunction and pulmonary hypertension and increased pulmonary blood flow.
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Affiliation(s)
- Shruti Sharma
- Program in Pulmonary Disease, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
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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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12
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Neuvonen PT, van den Berg AA. Postoperative Coma in a Child with Carnitine Palmitoyltransferase I Deficiency. Anesth Analg 2001. [DOI: 10.1213/00000539-200103000-00017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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13
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Neuvonen PT, van den Berg AA. Postoperative coma in a child with carnitine palmitoyltransferase I deficiency. Anesth Analg 2001; 92:646-7. [PMID: 11226093 DOI: 10.1097/00000539-200103000-00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
IMPLICATIONS We describe prolonged drowsiness proceeding to hepatic encephalopathy in a child with sickle cell trait and carnitine palmitoyltransferase deficiency. The latter defect of fatty acid metabolism is associated with striated muscle dysfunction and hepatic failure.
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Affiliation(s)
- P T Neuvonen
- Department of Anesthesia, King Fahd Armed Forces Hospital, Jeddah, Saudi Arabia.
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14
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Sim KG, Wiley V, Carpenter K, Wilcken B. Carnitine palmitoyltransferase I deficiency in neonate identified by dried blood spot free carnitine and acylcarnitine profile. J Inherit Metab Dis 2001; 24:51-9. [PMID: 11286383 DOI: 10.1023/a:1005606805951] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A neonate at risk for hepatic carnitine palmitoyltransferase I (L-CPT I) deficiency was investigated from birth. The free carnitine and acylcarnitine profile in dried whole blood filter paper samples collected at ages 1 and 4 days showed a markedly elevated concentration of free carnitine (141 and 142 micromol/L, respectively), normal concentrations of acetyl- and propionylcarnitine, with the near absence of all other species. The diagnosis was confirmed by in vitro fatty acid oxidation screening assays and enzyme assay in cultured skin fibroblasts. Retrospective study of the newborn whole blood sample of the index case showed a similar profile (free carnitine 181 micromol/L). The newborn population distribution of free carnitine (n = 143,981) showed that only three samples had free carnitine > 140 micromol/L (>99.9th centile), two were from L-CPT I-deficient neonates and one from a baby with sepsis. While there are other conditions that can cause elevated concentrations of free carnitine, an isolated elevation of free carnitine only in an apparently healthy term neonate warrants further investigation to exclude L-CPT I deficiency.
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Affiliation(s)
- K G Sim
- New South Wales Biochemical Genetics Services and Newborn Screening, The Children's Hospital at Westmead (Sydney), Australia
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15
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Vianey-Saban C, Bouvier R, Cochat P, Buenerd A, Divry P, Dumoulin R, Cordier MP. Antenatal expression of multiple acyl-CoA dehydrogenase deficiency. J Inherit Metab Dis 2000; 23:345-8. [PMID: 10896290 DOI: 10.1023/a:1005623028638] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- C Vianey-Saban
- Service de Biochimie Pédiatrique, Hôpital Debrousse, Lyon, France.
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16
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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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17
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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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Merinero B, Pascual Pascual SI, Pérez-Cerdá C, Gangoiti J, Castro M, Garcia MJ, Pascual Castroviejo I, Vianey-Saban C, Andresen B, Gregersen N, Ugarte M. Adolescent myopathic presentation in two sisters with very long-chain acyl-CoA dehydrogenase deficiency. J Inherit Metab Dis 1999; 22:802-10. [PMID: 10518280 DOI: 10.1023/a:1005553907216] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Two sisters were investigated at the ages of 20 and 13 years owing to persistently increased serum creatine kinase and recurrent episodes of rhabdomyolysis after emotional stress in the older and myalgias in the younger. The finding of increased levels of cis-5-tetradecenoic acid (C14:1) in plasma, severe hypocarnitinaemia and the absence of a pathological dicarboxylic aciduria in both sisters suggested a very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. Reduced [1-(14)C]palmitate oxidation and deficient mitochondrial VLCAD activity in fibroblasts were found. Mutation analysis revealed compound heterozygosity for Asp365His and Arg410His changes. This late-onset, milder clinical presentation differs from the other two more severe infantile phenotypes described, since there is no hypoglycaemia or cardiac disease. Fatty acid oxidation defects should be investigated in all cases with rhabdomyolysis beginning in adolescence or early adulthood.
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Affiliation(s)
- B Merinero
- Dpto. Biología Molecular, Universidad Autónoma Madrid, Spain
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19
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Abstract
Carnitine functions as a substrate for a family of enzymes, carnitine acyltransferases, involved in acyl-coenzyme A metabolism and as a carrier for long-chain fatty acids into mitochondria. Carnitine biosynthesis and/or dietary carnitine fulfill the body's requirement for carnitine. To date, a genetic disorder of carnitine biosynthesis has not been described. A genetic defect in the high-affinity plasma membrane carnitine-carrier(in) leads to renal carnitine wasting and primary carnitine deficiency. Myopathic carnitine deficiency could be due to an increase in efflux moderated by the carnitine-carrier(out). Defects in the carnitine transport system for fatty acids in mitochondria have been described and are being examined at the molecular and pathophysiological levels. the nutritional management of these disorders includes a high-carbohydrate, low-fat diet and avoidance of those events that promote fatty acid oxidation, such as fasting, prolonged exercise, and cold. Large-dose carnitine treatment is effective in systemic carnitine deficiency.
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Affiliation(s)
- J Kerner
- Department of Veteran Affairs Medical Center, Department of Nutrition, Cleveland, USA
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Vianey-Saban C, Divry P, Brivet M, Nada M, Zabot MT, Mathieu M, Roe C. Mitochondrial very-long-chain acyl-coenzyme A dehydrogenase deficiency: clinical characteristics and diagnostic considerations in 30 patients. Clin Chim Acta 1998; 269:43-62. [PMID: 9498103 DOI: 10.1016/s0009-8981(97)00185-x] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Very-long-chain acyl-CoA dehydrogenase (VLCAD) is an enzyme catalyzing the dehydrogenation of long-chain fatty acids in the first step of mitochondrial fatty acid oxidation. Using an ETF (electron transfer flavoprotein, the physiological electron acceptor of VLCAD) reduction assay, we identified VLCAD deficiency in cultured skin fibroblasts or liver tissue from 30 patients in 27 families. They clinically presented two phenotypes: a 'severe' presentation characterized by an early onset of symptoms, with hypertrophic cardiomyopathy and a high incidence of death, and a 'mild' form with hypoketotic hypoglycaemia, resembling MCAD (medium-chain acyl-CoA dehydrogenase) deficiency. Cells isolated from patients who develop cardiomyopathy characteristically accumulate longer-chain length acylcarnitines (hexadecanoylcarnitine and tetradecanoylcarnitine) when incubated with palmitate. However, cells from patients with the hypoglycaemic presentation produced relatively shorter-chain-length intermediates (mainly dodecanoylcarnitine). Inhibition of carnitine palmitoyl transferase I, in vitro, eliminated these intermediates with cells from both phenotypes indicating their intramitochondrial origin. Although the explanation for these distinct biochemical findings is not obvious, the correlation with the two phenotypes provides an opportunity for accurate prognosis and early implementation of appropriate treatment. Prenatal diagnosis of this life-threatening disorder was successfully performed in seven pregnancies in six of those families by assay of trophoblasts or amniocytes. In an at risk family, diagnosis of an affected fetus by measurement of VLCAD activity in noncultured chorionic villi allowed termination of the pregnancy before 13 weeks of gestation.
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Affiliation(s)
- C Vianey-Saban
- Unité d'Etude des Maladies Métaboliques, Hôpital Debrousse, Lyon, France
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21
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Slama A, Brivet M, Boutron A, Legrand A, Saudubray JM, Demaugre F. Complementation analysis of carnitine palmitoyltransferase I and II defects. Pediatr Res 1996; 40:542-6. [PMID: 8888280 DOI: 10.1203/00006450-199610000-00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Carnitine palmitoyltransferase (CPT) consists of two activities located in the outer (CPT I) and the inner (CPT II) mitochondrial membranes. CPT II deficiency in the adult as well as in the infantile form of the disease has been shown to result from mutations in the CPT II cDNA. Nothing is known regarding the genetic defect in CPT I deficiency. We carried out complementation experiments between CPT I- and infantile CPT II-deficient cell lines. Restoration of 3H2O release from [9,10(n)-3H]-palmitate was chosen as criterion of complementation. As expected, no complementation was observed in heteropolykaryons resulting from fusions between CPT II-deficient cells. Similar results were obtained in fusions between CPT I-deficient cells, suggesting that the enzymatic defect in these cell lines results from mutations in the same gene. Conversely, complementation was observed in fusions between CPT I- and CPT II-deficient cells. These data support that CPT I and CPT II defects result from mutations in distinct genes. Palmitate oxidation by control or CPT I-deficient cell lines was decreased when cocultured with infantile CPT II-deficient cell lines. This effect, not observed in coculture including an adult CPT II-deficient cell line, was carnitine-dependent. The possible mechanism of this effect, suppressed by a high carnitine concentration, is discussed.
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Affiliation(s)
- A Slama
- Laboratoire de Biochimie, CHU de Bicêtre, Paris, France
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Affiliation(s)
- J H Walter
- Willink Biochemical Genetics Unit, Royal Manchester Children's Hospital, Pendlebury
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23
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Villard J, Fischer A, Mandon G, Collombet JM, Taroni F, Mousson B. Recurrent myoglobinuria due to carnitine palmitoyltransferase II deficiency: expression of the molecular phenotype in cultured muscle cells. J Neurol Sci 1996; 136:178-81. [PMID: 8815169 DOI: 10.1016/0022-510x(95)00326-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Carnitine palmitoyltransferase II deficiency (CPT II) is an autosomal recessive disorder and the most frequent cause of hereditary myoglobinuria. We report the case of a young man who presented a severe fever-induced episode of rhabdomyolysis and myoglobinuria resulting in acute renal failure. Cultured skeletal muscle cells have been used for the biochemical and molecular characterization of the defect in this patient. Immunoblot analysis revealed reduced steady-state level of CPT II protein. A PCR-based method detected the common Ser113Leu substitution only in one allele, suggesting that the patient is a compound heterozygote for this common mutation and a different as yet unidentified mutation.
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Affiliation(s)
- J Villard
- Department of Medicine, Hôpital Cantonal, Geneva, Switzerland
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Vianey-Saban C, Stremler N, Paut O, Buttin T, Divry P, Zabot MT, Camboulives J, Mathieu M, Mousson B. Infantile form of carnitine palmitoyltransferase II deficiency in a girl with rapid fatal onset. J Inherit Metab Dis 1995; 18:362-3. [PMID: 7474909 DOI: 10.1007/bf00710434] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- C Vianey-Saban
- Unité d'Etude des Maladies Métaboliques, Hôpital Debrouse, Lyon, France
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Abstract
The oxidation of long-chain fatty acids requires a series of enzymes which are located in or on the mitochondrial membranes. These include carnitine palmitoyltransferases I and II, a carnitine-acylcarnitine translocase and, newly discovered, very long-chain acyl-CoA dehydrogenase and the mitochondrial trifunctional protein. These last two chain-shorten acyl-CoA esters to the point where they can be transferred to the more soluble medium- and short-chain-specific enzymes within the mitochondrial matrix. The disorders of long-chain fatty acid oxidation show a rather similar range of clinical and biochemical features, though with different emphasis in the different conditions. Patients with severe defects usually present early with acute attacks of hypoketotic hypoglycaemia and impaired liver function, or with cardiomyopathy or cardiac arrhythmia. In milder variants, skeletal myopathy with intermittent myoglobinuria develops later in life. 3-Hydroxyacyl-CoA dehydrogenase deficiency is unusual in producing peripheral neuropathy and retinitis pigmentosa. Treatment is based on the avoidance of fasting and replacement of normal dietary fat by medium-chain triglyceride, the medium-chain fatty acids entering the mitochondria in a carnitine-independent manner and bypassing the long-chain part of the spiral. Diagnosis must ultimately be based on direct assay of the enzyme involved, but preliminary indicators may come from determination of carnitine and intermediate metabolites in plasma, urinary organic acid profiling, and radioisotopic screening assays with lymphocytes or cultured fibroblasts.
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Affiliation(s)
- R J Pollitt
- Neonatal Screening Laboratory, Children's Hospital, Sheffield, UK
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Vallée L, Fontaine M, Nuyts JP, Ricart G, Krivosic I, Divry P, Vianey-Saban C, Lhermitte M, Vamecq J. Stroke, hemiparesis and deficient mitochondrial beta-oxidation. Eur J Pediatr 1994; 153:598-603. [PMID: 7957409 DOI: 10.1007/bf02190669] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We describe on a 3-year-old child referred for evaluation and therapy of a cerebral vascular accident with residual hemiplegia and partial epilepsy. Metabolic investigations initially showed normal urinary organic acids as well as normal blood and urinary amino acids. Blood carnitine fractions had been pathological and a secondary carnitine deficiency was diagnosed and treated by oral L-carnitine supplementation. During carnitine treatment, abnormal urinary acylcarnitine profiles were noticed with excessive amounts of several carnitine esters including propionylcarnitine, butyryl- and/or isobutyryl-carnitine, isovaleryl- and/or 2-methylbutyryl-carnitine, hexanoylcarnitine and octanoylcarnitine. Subsequently, an urinary organic acid profile suggestive of glutaric aciduria type II was recorded during a clinical decompensation crisis. Morphological and biochemical studies on skeletal muscle and skin fibroblasts were performed and confirmed the existence of a defect of the mitochondrial beta-oxidation pathways with lipidic myopathy, reduced palmitate and octanoate oxidation rates in cultured fibroblasts. Glutaric aciduria type II increases the list of metabolic disorders characterized by hemiplegia and other sequelae of brain ischaemia such as stroke-like episode, seizures, aphasia, ataxia and myoclonia, similar to those seen in MELAS.
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Affiliation(s)
- L Vallée
- North France Center for the Study of Childhood Epilepsy, Hôpital B, Centre Hospitalo-Universitaire de Lille, France
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Pande SV, Murthy MS. Carnitine-acylcarnitine translocase deficiency: implications in human pathology. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1226:269-76. [PMID: 8054358 DOI: 10.1016/0925-4439(94)90037-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- S V Pande
- Laboratory of Intermediary Metabolism, Clinical Research Institute of Montreal, Quebec, Canada
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28
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Abstract
OBJECTIVE To review the current understanding of the rapidly changing field of disorders of fatty acid metabolism and to discuss the future directions for research. DESIGN A literature review of the basic biochemistry of the beta-oxidation pathway and clinical cases of defects of fatty acid metabolism are presented, and the diagnosis and treatment of such defects are discussed. MATERIAL AND METHODS In many cases, a correct diagnosis will be made only if these disorders are specifically considered and appropriate tests are obtained, because results of screening tests for other organic acidemias are often normal in these entities. RESULTS The first disorder of fatty acid metabolism was described only 20 years ago. Since then, at least 15 different inborn errors of metabolism that affect beta-oxidation have been identified, most in the past 10 years. Within the past 5 years, investigators have realized that a deficiency of one of these enzymes, medium-chain acyl coenzyme A dehydrogenase, may be one of the most common inborn errors of metabolism. This disorder may have a frequency equal to that of phenylketonuria in some populations in the United States and northern Europe. Approximately 1 to 3% of all unexplained deaths during infancy and childhood are probably related to disorders of beta-oxidation. Diagnosis of these disorders can be difficult because of the intermittent nature of the excretion of characteristic compounds. The mainstay of therapy for defects of beta-oxidation is avoidance of fasting. CONCLUSION All patients with a suspected defect of fatty acid metabolism should be assessed and monitored by a specialist trained in the care of such patients. Continued improvements in the ability to diagnose and treat these disorders will be directly linked to new advances in the basic research on these enzymes. Movements to screen newborns for medium-chain acyl coenzyme A dehydrogenase are under way in some medical centers. Proposed tests include metabolite analysis or direct mutation analysis (or both) from blood spots from newborn screening cards already obtained for every newborn in the United States.
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Affiliation(s)
- J Vockley
- Department of Medical Genetics, Mayo Clinic Rochester, MN 55905
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