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Yazıcı H, Ak G, Çelik MY, Erdem F, Yanbolu AY, Er E, Bozacı AE, Güvenç MS, Aykut A, Durmaz A, Canda E, Uçar SK, Çoker M. Experience with carnitine palmitoyltransferase II deficiency: diagnostic challenges in the myopathic form. J Pediatr Endocrinol Metab 2024; 37:33-41. [PMID: 37925743 DOI: 10.1515/jpem-2023-0298] [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: 06/23/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023]
Abstract
OBJECTIVES Carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive disorder of long-chain fatty acid oxidation. Three clinical phenotypes, lethal neonatal form, severe infantile hepatocardiomuscular form, and myopathic form, have been described in CPT II deficiency. The myopathic form is usually mild and can manifest from infancy to adulthood, characterised by recurrent rhabdomyolysis episodes. The study aimed to investigate the clinical features, biochemical, histopathological, and genetic findings of 13 patients diagnosed with the myopathic form of CPT II deficiency at Ege University Hospital. METHODS A retrospective study was conducted with 13 patients with the myopathic form of CPT II deficiency. Our study considered demographic data, triggers of recurrent rhabdomyolysis attacks, biochemical metabolic screening, and molecular analysis. RESULTS Ten patients were examined for rhabdomyolysis of unknown causes. Two patients were diagnosed during family screening, and one was diagnosed during investigations due to increased liver function tests. Acylcarnitine profiles were normal in five patients during rhabdomyolysis. Genetic studies have identified a c.338C>T (p.Ser113Leu) variant homozygous in 10 patients. One patient showed a novel frameshift variant compound heterozygous with c.338C>T (p.Ser113Leu). CONCLUSIONS Plasma acylcarnitine analysis should be preferred as it is superior to DBS acylcarnitine analysis in diagnosing CPT II deficiency. Even if plasma acylcarnitine analysis is impossible, CPT2 gene analysis should be performed. Our study emphasizes that CPT II deficiency should be considered in the differential diagnosis of recurrent rhabdomyolysis, even if typical acylcarnitine elevation does not accompany it.
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Affiliation(s)
- Havva Yazıcı
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Gunes Ak
- Department of Clinical Biochemistry, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Merve Yoldas Çelik
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Fehime Erdem
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Ayse Yuksel Yanbolu
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Esra Er
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Ayse Ergül Bozacı
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Merve Saka Güvenç
- Department of Medical Genetics, Tepecik Training and Research Hospital, Izmir, Türkiye
| | - Ayca Aykut
- Department of Medical Genetics, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Asude Durmaz
- Department of Medical Genetics, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Ebru Canda
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Sema Kalkan Uçar
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
| | - Mahmut Çoker
- Department of Inborn Errors of Metabolism, Ege University Faculty of Medicine, Izmir, Türkiye
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Nalini A, Vengalil S, Polavarapu K, Preethish-Kumar V, Nashi S, Arunachal G, Chawla T, Bardhan M, Mohan D, Christopher R, Bevinahalli N, Kulanthaivelu K, Nishino I, Faruq M. Mutation spectrum of primary lipid storage myopathies. Ann Indian Acad Neurol 2022; 25:106-113. [PMID: 35342266 PMCID: PMC8954319 DOI: 10.4103/aian.aian_333_21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 10/16/2021] [Accepted: 10/27/2021] [Indexed: 11/04/2022] Open
Abstract
Background: Lipid storage myopathies (LSM) constitute an important group of treatable myopathies. Genetic testing is essential for confirming the diagnosis and also helps in explaining phenotypic heterogeneity. The objective of this study was to describe the clinical features and genetic spectrum of LSM seen in a quaternary referral center in India. Methods: Eleven cases of suspected LSM underwent clinical, biochemical, histopathological and genetic evaluation. Tandem Mass Spectrometry and clinical exome sequencing with Sanger validation were performed. Results: All patients had exertion induced myalgia and either progressive or episodic limb girdle muscle weakness (LGMW). The age of onset ranged 10 to 31 years (mean- 21 ± 6.7y), age at presentation- 14 to 49 years (mean- 26.5 ± 9.5y). Mutations identified: ETFDH = 5, CPT2 = 3, FLAD1 = 1, ACADVL = 1, FLAD1 = 1. Dropped head syndrome was seen in two patients with ETFDH mutations. Bulbar symptoms and Beevor's sign were noted in a patient with FLAD1 variant. Novel variants were identified in seven patients. Conclusions: This is the first report on the genetic spectrum of LSM from India. LSM should be considered in patients with exertion induced myalgias, LGMW, cranial nerve involvement or dropped head syndrome. Genetic testing is essential for identification of these treatable disorders.
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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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Abstract
Fatty acid oxidation disorders (FAOD) are a group of rare, autosomal recessive, metabolic disorders caused by variants of the genes for the enzymes and proteins involved in the transport and metabolism of fatty acids in the mitochondria. Those affected by FAOD are unable to convert fatty acids into tricarboxylic acid cycle intermediates such as acetyl-coenzyme A, resulting in decreased adenosine triphosphate and glucose for use as energy in a variety of high-energy-requiring organ systems. Signs and symptoms may manifest in infants but often also appear in adolescents or adults during times of increased metabolic demand, such as fasting, physiologic stress, and prolonged exercise. Patients with FAOD present with a highly heterogeneous clinical spectrum. The most common clinical presentations include hypoketotic hypoglycemia, liver dysfunction, cardiomyopathy, rhabdomyolysis, and skeletal myopathy, as well as peripheral neuropathy and retinopathy in some subtypes. Despite efforts to detect FAOD through newborn screening and manage patients early, symptom onset can be sudden and serious, even resulting in death. Therefore, it is critical to identify quickly and accurately the key signs and symptoms of patients with FAOD to manage metabolic decompensations and prevent serious comorbidities.
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Affiliation(s)
| | - Erin MacLeod
- Children's National Hospital, Washington, DC, USA
| | | | - Bryan Hainline
- Indiana University School of Medicine, Indianapolis, IN, USA
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Schizophrenic Psychosis Symptoms in a Background of Mild-To-Moderate Carnitine Palmitoyltransferase II Deficiency: A Case Report. REPORTS 2020. [DOI: 10.3390/reports3040031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Schizophrenia is a multifaceted mental illness characterized by cognitive and neurobehavioral abnormalities. Carnitine palmitoyltransferase II (CPT II) deficiency is a metabolic disorder resulting in impaired transport of long-chain fatty acids from the cytosol to the mitochondrial inner membrane, where fatty acid β-oxidation takes place. Here, we present an interesting clinical case of an adolescent male that presented with psychosis and a history of mild-to-moderate CPT II deficiency. To identify germline genetic variation that may contribute to the phenotypes observed, we performed whole-exome sequencing on DNA from the proband, unaffected fraternal twin, and biological parents. The proband was identified to be homozygous for the p.Val368Ile and heterozygous for the p.Met647Val variant in CPT2. Each of these variants are benign on their own; however, their combined effect is unclear. Further, variation was identified in the dopamine β-hydroxylase (DBH) gene (c.339+2T>C), which may contribute to decreased activity of DBH; however, based on the patient’s presentation, severe DBH deficiency is unlikely. In conclusion, the variants identified in this study do not clearly explain the observed patient phenotypes, indicating that the complex phenotypes are likely caused by an interplay of genetic and environmental factors that warrant further investigation.
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Abstract
Pediatric rhabdomyolysis is a common diagnosis that pediatricians need to be able to recognize because prompt treatment can prevent potential complications, such as acute kidney injury. The triggers for rhabdomyolysis are extensive, with viruses being the most common cause in pediatric patients. The pathophysiology behind rhabdomyolysis is complex and still being researched, but having a firm understanding of the cascade that results when muscle injury occurs is essential for proper management. Guidelines for managing pediatric rhabdomyolysis currently do not exist, but this article aims to review the available literature and give clinicians a general approach to aid in history taking, physical examination, diagnosis, acute management, follow-up, and prevention.
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Affiliation(s)
- Heidi S Szugye
- Cleveland Clinic Children's, Cleveland Clinic Lerner College of Medicine, Cleveland, OH
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Yamada K, Osawa Y, Kobayashi H, Hasegawa Y, Fukuda S, Yamaguchi S, Taketani T. Serum C14:1/C12:1 ratio is a useful marker for differentiating affected patients with very long-chain acyl-CoA dehydrogenase deficiency from heterozygous carriers. Mol Genet Metab Rep 2019; 21:100535. [PMID: 31844625 PMCID: PMC6895747 DOI: 10.1016/j.ymgmr.2019.100535] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/20/2019] [Indexed: 10/28/2022] Open
Abstract
Introduction Various markers, such as C14:1 and the C14:1/C2 ratio, are used as diagnostic markers of very long-chain acyl-CoA dehydrogenase deficiency (VLCADD). However, the levels of these markers in patients with VLCADD overlap with those in heterozygous carriers and even healthy subjects. Materials and methods In twenty-three affected patients and 15 heterozygous carriers with VLCADD, the accuracies of C14:1, C14:1/C12:1, C14:1/C2, and C14:1/C16 in dried blood spots (DBS) and serum were statistically estimated. Results Among the serum markers, the sensitivity, specificity, positive predictive value, negative predictive value, false-positive rate, false-negative rate, and validity of C14:1/C12:1 were superior to those of C14:1, C14:1/C2, and C14:1/C16, but C14:1/C2 demonstrated a statistical advantage compared with only C14:1 and C14:1/C16. Elevation in serum C14:1/C12:1 was observed in only one heterozygous carrier, whereas almost half of the carriers displayed false positive results for the other markers. Among the DBS markers, although the accuracy of C14:1/C2 was ostensibly the best, no statistical significance was observed. Discussion Serum C14:1/C12:1 might be useful for differentiating patients with VLCADD from heterozygous carriers. Although serum C14:1/C2 was significantly useful for the detection of VLCADD, this marker could not distinguish the affected patients from carriers. C14:1/C12:1 might be optimal compared with the other markers.
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Affiliation(s)
- Kenji Yamada
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Yoshimitsu Osawa
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan.,Department of Pediatrics, Graduate School of Medicine, Gunma University, 3-39-22, Showa-machi, Maebashi, Gunma 371-8511, Japan
| | - Hironori Kobayashi
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Yuki Hasegawa
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Seiji Fukuda
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Seiji Yamaguchi
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Takeshi Taketani
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
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Management and diagnosis of mitochondrial fatty acid oxidation disorders: focus on very-long-chain acyl-CoA dehydrogenase deficiency. J Hum Genet 2018; 64:73-85. [PMID: 30401918 DOI: 10.1038/s10038-018-0527-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/15/2018] [Accepted: 10/21/2018] [Indexed: 12/31/2022]
Abstract
Mitochondrial fatty acid oxidation disorders (FAODs) are caused by defects in β-oxidation enzymes, including very long-chain acyl-CoA dehydrogenase (VLCAD), trifunctional protein (TFP), carnitine palmitoyltransferase-2 (CPT2), carnitine-acylcarnitine translocase (CACT) and others. During prolonged fasting, infection, or exercise, patients with FAODs present with hypoglycemia, rhabdomyolysis, cardiomyopathy, liver dysfunction, and occasionally sudden death. This article describes the diagnosis, newborn screening, and treatment of long-chain FAODs with a focus on VLCAD deficiency. VLCAD deficiency is generally classified into three phenotypes based on onset time, but the classification should be comprehensively determined based on genotype, residual enzyme activity, and clinical course, due to a lack of apparent genotype-phenotype correlation. With the expansion of newborn screening for FAODs, several issues have arisen, such as missed detection, overdiagnosis (including detection of benign/asymptomatic type), and poor prognosis of the neonatal-onset form. Meanwhile, dietary management and restriction of exercise have been unnecessary for patients with the benign/asymptomatic type of VLCAD deficiency with a high fatty acid oxidation flux score. Although L-carnitine therapy for VLCAD/TFP deficiency has been controversial, supplementation with L-carnitine may be accepted for CPT2/CACT and multiple acyl-CoA dehydrogenase deficiencies. Recently, a double-blind, randomized controlled trial of triheptanoin (seven-carbon fatty acid triglyceride) versus trioctanoin (regular medium-chain triglyceride) was conducted and demonstrated improvement of cardiac functions on triheptanoin. Additionally, although the clinical efficacy of bezafibrate remains controversial, a recent open-label clinical trial showed efficacy of this drug in improving quality of life. These drugs may be promising for the treatment of FAODs, though further studies are required.
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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: 194] [Impact Index Per Article: 32.3] [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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