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Ye L, Chen H, Wang J, Tsim KWK, Wang Y, Shen X, Lei H, Liu Y. Aflatoxin B 1-induced liver pyroptosis is mediated by disturbing the gut microbial metabolites: The roles of pipecolic acid and norepinephrine. JOURNAL OF HAZARDOUS MATERIALS 2024; 474:134822. [PMID: 38850943 DOI: 10.1016/j.jhazmat.2024.134822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024]
Abstract
The disturbed gut microbiota is a key factor in activating the aflatoxin B1 (AFB1)-induced liver pyroptosis by promoting inflammatory hepatic injury; however, the pathogen associated molecular pattern (PAMP) from disturbed gut microbiota and its mechanism in activating liver pyroptosis remain undefined. By transplanting AFB1-originated fecal microbiota and sterile fecal microbial metabolites filtrate, we determined the association of PAMP in AFB1-induced liver pyroptosis. Notably, AFB1-originated sterile fecal microbial metabolites filtrate were more active in triggering liver pyroptosis in mice, as compared to parental fecal microbiota. This result supported a critical role of the metabolic homeostasis of gut microbiota in AFB1-induced liver pyroptosis, rather than an injurious response to direct exposure of AFB1 in liver. Among the gut-microbial metabolites, pipecolic acid and norepinephrine were proposed to bind TLR4 and NLRP3, the upstream proteins of pyroptosis signaling pathway. Besides, the activations of TLR4 and NLRP3 were linearly correlated with the concentrations of pipecolic acid and norepinephrine in the serum of mice. In silenced expression of TLR4 and NLRP3 in HepG2 cells, pipecolic acid or norepinephrine did not able to activate hepatocyte pyroptosis. These results demonstrated the necessity of gut microbial metabolism in sustaining liver homeostasis, as well as the potential to provide new insights into targeted intervention for AFB1 hepatotoxicity.
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Affiliation(s)
- Lin Ye
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China; Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., 510700 Guangzhou, China
| | - Huodai Chen
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China
| | - Jie Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China
| | - Karl Wah Keung Tsim
- Division of Life Science, Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yurun Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China
| | - Xing Shen
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China
| | - Hongtao Lei
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China; Guangdong Laboratory for Lingnan Modern Agriculture, 510642 Guangzhou, China; Heyuan Branch, Guangdong Laboratory for Lingnan Modern Agriculture, 517000 Heyuan, China.
| | - Yunle Liu
- Guangdong Provincial Key Laboratory of Food Quality and Safety / National-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, 510642 Guangzhou, China; Guangdong Laboratory for Lingnan Modern Agriculture, 510642 Guangzhou, China; Heyuan Branch, Guangdong Laboratory for Lingnan Modern Agriculture, 517000 Heyuan, China.
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2
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Khalil Y, Footitt E, Vootukuri R, Wempe MF, Coughlin CR, Batzios S, Wilson MP, Kožich V, Clayton PT, Mills PB. Assessment of urinary 6-oxo-pipecolic acid as a biomarker for ALDH7A1 deficiency. J Inherit Metab Dis 2024. [PMID: 39038845 DOI: 10.1002/jimd.12783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/20/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
ALDH7A1 deficiency is an epileptic encephalopathy whose seizures respond to treatment with supraphysiological doses of pyridoxine. It arises as a result of damaging variants in ALDH7A1, a gene in the lysine catabolism pathway. α-Aminoadipic semialdehyde (α-AASA) and Δ1-piperideine-6-carboxylate (P6C), which accumulate because of the block in the lysine pathway, are diagnostic biomarkers for this disorder. Recently, it has been reported that 6-oxo-pipecolic acid (6-oxo-PIP) also accumulates in the urine, CSF and plasma of ALDH7A1-deficient individuals and that, given its improved stability, it may be a more suitable biomarker for this disorder. This study measured 6-oxo-PIP in urine from a cohort of 30 patients where α-AASA was elevated and showed that it was above the normal range in all those above 6 months of age. However, 6-oxo-PIP levels were within the normal range in 33% of the patients below 6 months of age. Levels increased with age and correlated with a decrease in α-AASA levels. Longitudinal analysis of urine samples from ALDH7A1-deficient patients who were on a lysine restricted diet whilst receiving supraphysiological doses of pyridoxine showed that levels of 6-oxo-PIP remained elevated whilst α-AASA decreased. Similar to α-AASA, we found that elevated urinary excretion of 6-oxo-PIP can also occur in individuals with molybdenum cofactor deficiency. This study demonstrates that urinary 6-oxo-PIP may not be a suitable biomarker for ALDH7A1 deficiency in neonates. However, further studies are needed to understand the biochemistry leading to its accumulation and its potential long-term side effects.
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Affiliation(s)
- Youssef Khalil
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Emma Footitt
- Department of Metabolic Paediatrics, Great Ormond Street Hospital, London, UK
| | - Reddy Vootukuri
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Michael F Wempe
- School of Pharmacy, Department of Pharmaceutical Sciences, University of Colorado, Aurora, Colorado, USA
| | - Curtis R Coughlin
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Spyros Batzios
- Department of Metabolic Paediatrics, Great Ormond Street Hospital, London, UK
| | - Matthew P Wilson
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
- Laboratory for Molecular Diagnosis, Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Viktor Kožich
- Department of Pediatrics and Inherited Metabolic Disorders, Charles University-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Peter T Clayton
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Philippa B Mills
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
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3
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Korasick DA, Buckley DP, Palpacelli A, Cursio I, Cesaroni E, Cheng J, Tanner JJ. Biochemical, structural, and computational analyses of two new clinically identified missense mutations of ALDH7A1. Chem Biol Interact 2024; 394:110993. [PMID: 38604394 PMCID: PMC11073572 DOI: 10.1016/j.cbi.2024.110993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/30/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024]
Abstract
Aldehyde dehydrogenase 7A1 (ALDH7A1) catalyzes a step of lysine catabolism. Certain missense mutations in the ALDH7A1 gene cause pyridoxine dependent epilepsy (PDE), a rare autosomal neurometabolic disorder with recessive inheritance that affects almost 1:65,000 live births and is classically characterized by recurrent seizures from the neonatal period. We report a biochemical, structural, and computational study of two novel ALDH7A1 missense mutations that were identified in a child with rare recurrent seizures from the third month of life. The mutations affect two residues in the oligomer interfaces of ALDH7A1, Arg134 and Arg441 (Arg162 and Arg469 in the HGVS nomenclature). The corresponding enzyme variants R134S and R441C (p.Arg162Ser and p.Arg469Cys in the HGVS nomenclature) were expressed in Escherichia coli and purified. R134S and R441C have 10,000- and 50-fold lower catalytic efficiency than wild-type ALDH7A1, respectively. Sedimentation velocity analytical ultracentrifugation shows that R134S is defective in tetramerization, remaining locked in a dimeric state even in the presence of the tetramer-inducing coenzyme NAD+. Because the tetramer is the active form of ALDH7A1, the defect in oligomerization explains the very low catalytic activity of R134S. In contrast, R441C exhibits wild-type oligomerization behavior, and the 2.0 Å resolution crystal structure of R441C complexed with NAD+ revealed no obvious structural perturbations when compared to the wild-type enzyme structure. Molecular dynamics simulations suggest that the mutation of Arg441 to Cys may increase intersubunit ion pairs and alter the dynamics of the active site gate. Our biochemical, structural, and computational data on two novel clinical variants of ALDH7A1 add to the complexity of the molecular determinants underlying pyridoxine dependent epilepsy.
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Affiliation(s)
- David A Korasick
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, United States
| | - David P Buckley
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, United States
| | | | - Ida Cursio
- Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Marche, Ancona, Italy
| | - Elisabetta Cesaroni
- Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Marche, Ancona, Italy
| | - Jianlin Cheng
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO, 65211, United States
| | - John J Tanner
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, United States; Department of Chemistry, University of Missouri, Columbia, MO, 65211, United States.
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4
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Fang C, Yang L, Xiao F, Yan K, Zhou W. Genotype and phenotype features and prognostic factors of neonatal-onset pyridoxine-dependent epilepsy: A systematic review. Epilepsy Res 2024; 202:107363. [PMID: 38636407 DOI: 10.1016/j.eplepsyres.2024.107363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/29/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024]
Abstract
Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is a rare autosomal recessive disorder due to a deficiency of α-aminoadipic semialdehyde dehydrogenase. This study aimed to systematically explore genotypic and phenotypic features and prognostic factors of neonatal-onset PDE. A literature search covering PubMed, Elsevier, and Web of Science was conducted from January 2006 to August 2023. We identified 56 eligible studies involving 169 patients and 334 alleles. The c.1279 G>C variant was the most common variant of neonatal-onset PDE (25.7 %). All patients were treated with pyridoxine; forty patients received dietary intervention therapy. 63.9 % of the patients were completely seizure-free; however, 68.6 % of the patients had neurodevelopmental delays. Additionally, homozygous c.1279 G>C variants were significantly associated with ventriculomegaly, abnormal white matter signal, and cysts (P<0.05). In contrast, homozygous c.1364 T>C was associated with clonic seizure (P=0.031). Pyridoxine used immediately at seizure onset was an independent protective factor for developmental delay (P=0.035; odds ratio [OR]: 3.14). Besides, pyridoxine used early in the neonatal period was a protective factor for language delay (P=0.044; OR: 4.59). In contrast, neonatal respiratory distress (P=0.001; OR: 127.44) and abnormal brain magnetic resonance imaging (P=0.049; OR: 3.64) were risk factors. Prenatal movement abnormality (P=0.041; OR: 20.56) and abnormal white matter signal (P=0.012; OR: 24.30) were risk factors for motor delay. Myoclonic seizure (P=0.023; OR: 7.13) and status epilepticus (P=0.000; OR: 9.93) were risk factors for breakthrough seizures. In conclusion, our study indicated that pyridoxine should be started immediately when unexplained neonatal seizures occur and not later than the neonatal period to prevent poor neurodevelopmental outcomes.
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Affiliation(s)
- Chuchu Fang
- Department of Neonatology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Lin Yang
- Department of Neonatology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China; Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Feifan Xiao
- Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Kai Yan
- Department of Neonatology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China.
| | - Wenhao Zhou
- Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China; Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
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5
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Funck D, Sinn M, Forlani G, Hartig JS. Guanidine production by plant homoarginine-6-hydroxylases. eLife 2024; 12:RP91458. [PMID: 38619227 PMCID: PMC11018352 DOI: 10.7554/elife.91458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024] Open
Abstract
Metabolism and biological functions of the nitrogen-rich compound guanidine have long been neglected. The discovery of four classes of guanidine-sensing riboswitches and two pathways for guanidine degradation in bacteria hint at widespread sources of unconjugated guanidine in nature. So far, only three enzymes from a narrow range of bacteria and fungi have been shown to produce guanidine, with the ethylene-forming enzyme (EFE) as the most prominent example. Here, we show that a related class of Fe2+- and 2-oxoglutarate-dependent dioxygenases (2-ODD-C23) highly conserved among plants and algae catalyze the hydroxylation of homoarginine at the C6-position. Spontaneous decay of 6-hydroxyhomoarginine yields guanidine and 2-aminoadipate-6-semialdehyde. The latter can be reduced to pipecolate by pyrroline-5-carboxylate reductase but more likely is oxidized to aminoadipate by aldehyde dehydrogenase ALDH7B in vivo. Arabidopsis has three 2-ODD-C23 isoforms, among which Din11 is unusual because it also accepted arginine as substrate, which was not the case for the other 2-ODD-C23 isoforms from Arabidopsis or other plants. In contrast to EFE, none of the three Arabidopsis enzymes produced ethylene. Guanidine contents were typically between 10 and 20 nmol*(g fresh weight)-1 in Arabidopsis but increased to 100 or 300 nmol*(g fresh weight)-1 after homoarginine feeding or treatment with Din11-inducing methyljasmonate, respectively. In 2-ODD-C23 triple mutants, the guanidine content was strongly reduced, whereas it increased in overexpression plants. We discuss the implications of the finding of widespread guanidine-producing enzymes in photosynthetic eukaryotes as a so far underestimated branch of the bio-geochemical nitrogen cycle and propose possible functions of natural guanidine production.
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Affiliation(s)
- Dietmar Funck
- Department of Chemistry, University of KonstanzKonstanzGermany
| | - Malte Sinn
- Department of Chemistry, University of KonstanzKonstanzGermany
| | - Giuseppe Forlani
- Department of Life Science and Biotechnology, University of FerraraFerraraItaly
| | - Jörg S Hartig
- Department of Chemistry, University of KonstanzKonstanzGermany
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6
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Global Metabolomics Discovers Two Novel Biomarkers in Pyridoxine-Dependent Epilepsy Caused by ALDH7A1 Deficiency. Int J Mol Sci 2022; 23:ijms232416061. [PMID: 36555701 PMCID: PMC9784804 DOI: 10.3390/ijms232416061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive developmental and epileptic encephalopathy caused by pathogenic variants in the ALDH7A1 gene (PDE-ALDH7A1), which mainly has its onset in neonates and infants. Early diagnosis and treatment are crucial to prevent severe neurological sequelae or death. Sensitive, specific, and stable biomarkers for diagnostic evaluations and follow-up examinations are essential to optimize outcomes. However, most of the known biomarkers for PDE lack these criteria. Additionally, there is little discussion regarding the interdependence of biomarkers in the PDE-ALDH7A1 metabolite profile. Therefore, the aim of this study was to understand the underlying mechanisms in PDE-ALDH7A1 and to discover new biomarkers in the plasma of patients using global metabolomics. Plasma samples from 9 patients with genetically confirmed PDE-ALDH7A1 and 22 carefully selected control individuals were analyzed by ultra high performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Two novel and reliable pyridoxine-independent diagnostic markers, 6-hydroxy-2-aminocaproic acid (HACA) and an isomer of C9H11NO4, were identified. Furthermore, a possible reaction mechanism is proposed for HACA. This study demonstrates the capability of global metabolomics in disease screening to detect established and novel biomarkers.
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7
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Zhang L, Li Q, Bao Y, Tan Y, Lametsch R, Hong H, Luo Y. Recent advances on characterization of protein oxidation in aquatic products: A comprehensive review. Crit Rev Food Sci Nutr 2022; 64:1572-1591. [PMID: 36122384 DOI: 10.1080/10408398.2022.2117788] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In addition to microbial spoilage and lipid peroxidation, protein oxidation is increasingly recognized as a major cause for quality deterioration of muscle-based foods. Although protein oxidation in muscle-based foods has attracted tremendous interest in the past decade, specific oxidative pathways and underlying mechanisms of protein oxidation in aquatic products remain largely unexplored. The present review covers the aspects of the origin and site-specific nature of protein oxidation, progress on the characterization of protein oxidation, oxidized proteins in aquatic products, and impact of protein oxidation on protein functionalities. Compared to meat protein oxidation, aquatic proteins demonstrate a less extent of oxidation on aromatic amino acids and are more susceptible to be indirectly oxidized by lipid peroxidation products. Different from traditional measurement of protein carbonyls and thiols, proteomics-based strategy better characterizes the targeted oxidation sites within proteins. The future trends using more robust and accurate targeted proteomics, such as parallel reaction monitoring strategy, to characterize protein oxidation in aquatic products are also given.
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Affiliation(s)
- Longteng Zhang
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Qian Li
- Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Yulong Bao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Yuqing Tan
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - René Lametsch
- Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Hui Hong
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Yongkang Luo
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
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8
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An Atypical Presentation of Pyridoxine-Dependent Epilepsy Diagnosed with Whole Exome Sequencing and Treated with Lysine Restriction and Supplementation with Arginine and Pyridoxine. Case Rep Genet 2022; 2022:7138435. [PMID: 36082373 PMCID: PMC9448604 DOI: 10.1155/2022/7138435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
Pyridoxine dependent-developmental and epileptic encephalopathy (PD-DEE) or pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive disorder caused by biallelic pathogenic variants in ALDH7A1. It classically presents as intractable infantile-onset seizures unresponsive to multiple antiepileptic drugs (AEDs) but with a profound response to large doses of pyridoxine (B6). We report a case of PDE with an atypical clinical presentation. The patient presented at 3 days of life with multifocal seizures, fever, increased work of breathing, decreased left ventricular systolic function, and lactic acidosis, raising suspicion for a mitochondrial disorder or infectious process. Within 1.5 weeks of presentation, seizure activity resolved with antiepileptic therapy. Whole exome sequencing (WES) revealed homozygous pathogenic variants in ALDH7A1 (c.1279G > C, p.E427Q) and confirmed the diagnosis of PDE. Follow-up biochemical testing demonstrated elevated urine pipecolic acid. In the second week of life, the patient was initiated on triple therapy, including pyridoxine supplementation, low lysine diet, and arginine supplementation, which he tolerated well. Urine pipecolic acid levels responded accordingly after initiation of therapy. Our case illustrates the diagnostic challenges in PDE, the utility of rapid WES in such cases, and the response in urine pipecolic acid to therapy.
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9
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Aquilano G, Linnér A, Ygberg S, Stödberg T, Henckel E. Case report: Fatal outcome of pyridoxine-dependent epilepsy presenting as respiratory distress followed by a circulatory collapse. Front Pediatr 2022; 10:940103. [PMID: 35967578 PMCID: PMC9366515 DOI: 10.3389/fped.2022.940103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Pyridoxine-dependent epilepsy is a rare autosomal recessive disease usually associated with neonatal seizures that do not respond to common antiseizure medications but are controlled by pyridoxine administration. Because the symptoms can mimic common neonatal disorders, the diagnosis can be initially missed or delayed. We report a fatal case of a boy who was initially diagnosed with respiratory distress, birth asphyxia, and persistent pulmonary hypertension and whose condition rapidly deteriorated during the first day of life.
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Affiliation(s)
- Giulia Aquilano
- Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden
| | - Agnes Linnér
- Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Sofia Ygberg
- Department of Child Neurology, Karolinska University Hospital, Stockholm, Sweden.,Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Center for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Stockholm, Sweden
| | - Tommy Stödberg
- Department of Child Neurology, Karolinska University Hospital, Stockholm, Sweden.,Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Ewa Henckel
- Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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10
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van Outersterp R, Engelke UF, Merx J, Berden G, Paul M, Thomulka T, Berkessel A, Huigen MC, Kluijtmans LA, Mecinović J, Rutjes FP, van Karnebeek CD, Wevers RA, Boltje TJ, Coene KL, Martens J, Oomens J. Metabolite Identification Using Infrared Ion Spectroscopy─Novel Biomarkers for Pyridoxine-Dependent Epilepsy. Anal Chem 2021; 93:15340-15348. [PMID: 34756024 PMCID: PMC8613736 DOI: 10.1021/acs.analchem.1c02896] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/25/2021] [Indexed: 11/30/2022]
Abstract
Untargeted liquid chromatography-mass spectrometry (LC-MS)-based metabolomics strategies are being increasingly applied in metabolite screening for a wide variety of medical conditions. The long-standing "grand challenge" in the utilization of this approach is metabolite identification─confidently determining the chemical structures of m/z-detected unknowns. Here, we use a novel workflow based on the detection of molecular features of interest by high-throughput untargeted LC-MS analysis of patient body fluids combined with targeted molecular identification of those features using infrared ion spectroscopy (IRIS), effectively providing diagnostic IR fingerprints for mass-isolated targets. A significant advantage of this approach is that in silico-predicted IR spectra of candidate chemical structures can be used to suggest the molecular structure of unknown features, thus mitigating the need for the synthesis of a broad range of physical reference standards. Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is an inborn error of lysine metabolism, resulting from a mutation in the ALDH7A1 gene that leads to an accumulation of toxic levels of α-aminoadipic semialdehyde (α-AASA), piperideine-6-carboxylate (P6C), and pipecolic acid in body fluids. While α-AASA and P6C are known biomarkers for PDE in urine, their instability makes them poor candidates for diagnostic analysis from blood, which would be required for application in newborn screening protocols. Here, we use combined untargeted metabolomics-IRIS to identify several new biomarkers for PDE-ALDH7A1 that can be used for diagnostic analysis in urine, plasma, and cerebrospinal fluids and that are compatible with analysis in dried blood spots for newborn screening. The identification of these novel metabolites has directly provided novel insights into the pathophysiology of PDE-ALDH7A1.
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Affiliation(s)
- Rianne
E. van Outersterp
- Institute
for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Udo F.H. Engelke
- Department
of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Jona Merx
- Institute
for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Giel Berden
- Institute
for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Mathias Paul
- Department
of Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne, Germany
| | - Thomas Thomulka
- Department
of Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne, Germany
| | - Albrecht Berkessel
- Department
of Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne, Germany
| | - Marleen C.D.G. Huigen
- Department
of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Leo A.J. Kluijtmans
- Department
of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Jasmin Mecinović
- University
of Southern Denmark, Department of Physics,
Chemistry and Pharmacy, Campusvej 55, 5230 Odense, Denmark
| | - Floris P.J.T. Rutjes
- Institute
for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Clara D.M. van Karnebeek
- Department
of Pediatrics-Metabolic Diseases, Radboud Center for Mitochondrial
Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Ron A. Wevers
- Department
of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Thomas J. Boltje
- Institute
for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Karlien L.M. Coene
- Department
of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Jonathan Martens
- Institute
for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jos Oomens
- Institute
for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Science
Park 908, 1098XH Amsterdam, The Netherlands
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11
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Engelke UF, van Outersterp RE, Merx J, van Geenen FA, van Rooij A, Berden G, Huigen MC, Kluijtmans LA, Peters TM, Al-Shekaili HH, Leavitt BR, de Vrieze E, Broekman S, van Wijk E, Tseng LA, Kulkarni P, Rutjes FP, Mecinović J, Struys EA, Jansen LA, Gospe SM, Mercimek-Andrews S, Hyland K, Willemsen MA, Bok LA, van Karnebeek CD, Wevers RA, Boltje TJ, Oomens J, Martens J, Coene KL. Untargeted metabolomics and infrared ion spectroscopy identify biomarkers for pyridoxine-dependent epilepsy. J Clin Invest 2021; 131:e148272. [PMID: 34138754 DOI: 10.1172/jci148272] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/16/2021] [Indexed: 12/30/2022] Open
Abstract
BackgroundPyridoxine-dependent epilepsy (PDE-ALDH7A1) is an inborn error of lysine catabolism that presents with refractory epilepsy in newborns. Biallelic ALDH7A1 variants lead to deficiency of α-aminoadipic semialdehyde dehydrogenase/antiquitin, resulting in accumulation of piperideine-6-carboxylate (P6C), and secondary deficiency of the important cofactor pyridoxal-5'-phosphate (PLP, active vitamin B6) through its complexation with P6C. Vitamin B6 supplementation resolves epilepsy in patients, but intellectual disability may still develop. Early diagnosis and treatment, preferably based on newborn screening, could optimize long-term clinical outcome. However, no suitable PDE-ALDH7A1 newborn screening biomarkers are currently available.MethodsWe combined the innovative analytical methods untargeted metabolomics and infrared ion spectroscopy to discover and identify biomarkers in plasma that would allow for PDE-ALDH7A1 diagnosis in newborn screening.ResultsWe identified 2S,6S-/2S,6R-oxopropylpiperidine-2-carboxylic acid (2-OPP) as a PDE-ALDH7A1 biomarker, and confirmed 6-oxopiperidine-2-carboxylic acid (6-oxoPIP) as a biomarker. The suitability of 2-OPP as a potential PDE-ALDH7A1 newborn screening biomarker in dried bloodspots was shown. Additionally, we found that 2-OPP accumulates in brain tissue of patients and Aldh7a1-knockout mice, and induced epilepsy-like behavior in a zebrafish model system.ConclusionThis study has opened the way to newborn screening for PDE-ALDH7A1. We speculate that 2-OPP may contribute to ongoing neurotoxicity, also in treated PDE-ALDH7A1 patients. As 2-OPP formation appears to increase upon ketosis, we emphasize the importance of avoiding catabolism in PDE-ALDH7A1 patients.FundingSociety for Inborn Errors of Metabolism for Netherlands and Belgium (ESN), United for Metabolic Diseases (UMD), Stofwisselkracht, Radboud University, Canadian Institutes of Health Research, Dutch Research Council (NWO), and the European Research Council (ERC).
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Affiliation(s)
- Udo Fh Engelke
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Jona Merx
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands
| | | | - Arno van Rooij
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory and
| | - Marleen Cdg Huigen
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Leo Aj Kluijtmans
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Tessa Ma Peters
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Hilal H Al-Shekaili
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia, Canada
| | - Erik de Vrieze
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sanne Broekman
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Laura A Tseng
- Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Purva Kulkarni
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Floris Pjt Rutjes
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands
| | - Jasmin Mecinović
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands.,Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Eduard A Struys
- Department of Clinical Chemistry, Amsterdam University Medical Centers, location VU Medical Centre, Amsterdam, Netherlands
| | - Laura A Jansen
- Division of Pediatric Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sidney M Gospe
- Departments of Neurology and Pediatrics, University of Washington, Seattle, Washington, USA.,Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Saadet Mercimek-Andrews
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Keith Hyland
- Medical Neurogenetics Laboratories, Atlanta, Georgia, USA
| | - Michèl Aap Willemsen
- Department of Pediatric Neurology, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Levinus A Bok
- Department of Pediatrics, Máxima Medical Centre, Veldhoven, Netherlands
| | - Clara Dm van Karnebeek
- Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Department of Pediatrics-Metabolic Diseases, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, Netherlands.,United for Metabolic Diseases (UMD), Netherlands
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Thomas J Boltje
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory and.,Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, Netherlands
| | | | - Karlien Lm Coene
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
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12
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Yazdani M, Elgstøen KBP. Is oxidative stress an overlooked player in pyridoxine-dependent epilepsy? A focused review. Seizure 2021; 91:369-373. [PMID: 34298455 DOI: 10.1016/j.seizure.2021.07.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 01/22/2023] Open
Abstract
Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive developmental and epileptic encephalopathy that is responsive to pharmacologic doses of vitamin B6. The deficiency of antiquitin, an enzyme involved in the catabolism of lysine, is believed to be its key molecular basis. Research to date has tended to focus on two known catabolic pathways of lysine, namely, saccharopine and pipecolic acid. However, the occurrence of oxidative stress and the presence of its metabolites have been only briefly highlighted in the literature. Owing to the importance of the topic and its potential for future diagnosis, prognosis and therapy, this paper reviews the suggested mechanisms of oxidative stress in antiquitin deficiency along with the proposed reactions and intermediates, and finally, discusses the challenges and opportunities.
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Affiliation(s)
- Mazyar Yazdani
- Metabolomics and Metabolic Molecular Biology Group, Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway.
| | - Katja Benedikte Prestø Elgstøen
- Metabolomics and Metabolic Molecular Biology Group, Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway
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13
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Coughlin CR, Tseng LA, Abdenur JE, Ashmore C, Boemer F, Bok LA, Boyer M, Buhas D, Clayton PT, Das A, Dekker H, Evangeliou A, Feillet F, Footitt EJ, Gospe SM, Hartmann H, Kara M, Kristensen E, Lee J, Lilje R, Longo N, Lunsing RJ, Mills P, Papadopoulou MT, Pearl PL, Piazzon F, Plecko B, Saini AG, Santra S, Sjarif DR, Stockler-Ipsiroglu S, Striano P, Van Hove JLK, Verhoeven-Duif NM, Wijburg FA, Zuberi SM, van Karnebeek CDM. Consensus guidelines for the diagnosis and management of pyridoxine-dependent epilepsy due to α-aminoadipic semialdehyde dehydrogenase deficiency. J Inherit Metab Dis 2021; 44:178-192. [PMID: 33200442 DOI: 10.1002/jimd.12332] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/21/2020] [Accepted: 11/13/2020] [Indexed: 12/19/2022]
Abstract
Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is an autosomal recessive condition due to a deficiency of α-aminoadipic semialdehyde dehydrogenase, which is a key enzyme in lysine oxidation. PDE-ALDH7A1 is a developmental and epileptic encephalopathy that was historically and empirically treated with pharmacologic doses of pyridoxine. Despite adequate seizure control, most patients with PDE-ALDH7A1 were reported to have developmental delay and intellectual disability. To improve outcome, a lysine-restricted diet and competitive inhibition of lysine transport through the use of pharmacologic doses of arginine have been recommended as an adjunct therapy. These lysine-reduction therapies have resulted in improved biochemical parameters and cognitive development in many but not all patients. The goal of these consensus guidelines is to re-evaluate and update the two previously published recommendations for diagnosis, treatment, and follow-up of patients with PDE-ALDH7A1. Members of the International PDE Consortium initiated evidence and consensus-based process to review previous recommendations, new research findings, and relevant clinical aspects of PDE-ALDH7A1. The guideline development group included pediatric neurologists, biochemical geneticists, clinical geneticists, laboratory scientists, and metabolic dieticians representing 29 institutions from 16 countries. Consensus guidelines for the diagnosis and management of patients with PDE-ALDH7A1 are provided.
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Affiliation(s)
- Curtis R Coughlin
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Laura A Tseng
- Department of Pediatrics Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Jose E Abdenur
- Division of Metabolic Disorders, CHOC Children's Hospital, Orange, California, USA
| | - Catherine Ashmore
- Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - François Boemer
- Department of Human Genetics, Centre Hospitalier Universitaire Sart-Tilman, Liège, Belgium
| | - Levinus A Bok
- Department of Pediatrics and Neonatology, Máxima Medical Center, Veldhoven, The Netherlands
| | - Monica Boyer
- Division of Metabolic Disorders, CHOC Children's Hospital, Orange, California, USA
| | - Daniela Buhas
- Division of Medical Genetics, Department of Specialized Medicine, Montreal Children's Hospital, McGill University Health Centre, Québec, Canada
| | - Peter T Clayton
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Anibh Das
- Clinic for Paediatric Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Hanka Dekker
- VKS: Dutch Patient Organization for Metabolic Diseases, Zwolle, The Netherlands
| | - Athanasios Evangeliou
- Division of Child Neurology and Inherited Metabolic Disorders, 4th Department of Pediatrics, Aristotle University of Thessaloniki, General Hospital Papageorgiou, Thessaloniki, Greece
| | - François Feillet
- Reference Center for Inborn Errors of Metabolism, Pediatric Unit, University Hospital of Nancy, Nancy, France
- INSERM UMR S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France
| | - Emma J Footitt
- Department of Metabolic Paediatrics, Great Ormond Street Hospital, London, UK
| | - Sidney M Gospe
- Division of Pediatric Neurology, Departments of Neurology and Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Hans Hartmann
- Clinic for Paediatric Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Majdi Kara
- Department of Pediatrics, University of Tripoli, Tripoli, Libya
| | - Erle Kristensen
- National Management of Newborn Screening and Advanced Laboratory Diagnostics in Inborn Errors of Metabolism, Department of Children and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Joy Lee
- Department of Metabolic Medicine, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Rina Lilje
- Department of Children and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Roelineke J Lunsing
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Philippa Mills
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Maria T Papadopoulou
- Division of Child Neurology and Inherited Metabolic Disorders, 4th Department of Pediatrics, Aristotle University of Thessaloniki, General Hospital Papageorgiou, Thessaloniki, Greece
| | - Phillip L Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Flavia Piazzon
- Neurometabolic Clinic, Children's Institute, University of Sao Paulo, Brazil
| | - Barbara Plecko
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Arushi G Saini
- Pediatric Neurology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Saikat Santra
- Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Damayanti R Sjarif
- Department of Child Health, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Sylvia Stockler-Ipsiroglu
- Division of Biochemical Genetics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS "G. Gaslini" Institute, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Johan L K Van Hove
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | | | - Frits A Wijburg
- Department of Pediatrics Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
| | - Clara D M van Karnebeek
- Department of Pediatrics Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, The Netherlands
- Department of Pediatrics, Amalia Children's Hospital, Radboud Centre for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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