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Snyder MT, Manor J, Gijavanekar C, Mizerik E, Kralik SF, Elsea SH, Machol K, Emrick L, Scaglia F. Heteroplasmic pathogenic m.12315G>A variant in MT-TL2 presenting with MELAS syndrome and depletion of nitric oxide donors. Am J Med Genet A 2024; 194:e63461. [PMID: 37953071 DOI: 10.1002/ajmg.a.63461] [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: 06/20/2023] [Revised: 09/14/2023] [Accepted: 10/19/2023] [Indexed: 11/14/2023]
Abstract
The MT-TL2 m.12315G>A pathogenic variant has previously been reported in five individuals with mild clinical phenotypes. Herein we report the case of a 5-year-old child with heteroplasmy for this variant who developed neurological regression and stroke-like episodes similar to those observed in mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Biochemical evaluation revealed depletion of arginine on plasma amino acid analysis and low z-scores for citrulline on untargeted plasma metabolomics analysis. These findings suggested that decreased availability of nitric oxide may have contributed to the stroke-like episodes. The use of intravenous arginine during stroke-like episodes and daily enteral L-citrulline supplementation normalized her biochemical values of arginine and citrulline. Untargeted plasma metabolomics showed the absence of nicotinamide and 1-methylnicotinamide, and plasma total glutathione levels were low; thus, nicotinamide riboside and N-acetylcysteine therapies were initiated. This report expands the phenotype associated with the rare mitochondrial variant MT-TL2 m.12315G>A to include neurological regression and a MELAS-like phenotype. Individuals with this variant should undergo in-depth biochemical analysis to include untargeted plasma metabolomics, plasma amino acids, and glutathione levels to help guide a targeted approach to treatment.
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Affiliation(s)
- Matthew T Snyder
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
| | - Joshua Manor
- Metabolic Diseases Unit, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Ramat Gan, Israel
| | - Charul Gijavanekar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Elizabeth Mizerik
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
| | - Stephen F Kralik
- Texas Children's Hospital, Houston, Texas, USA
- Department of Radiology, Baylor College of Medicine, Houston, Texas, USA
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Keren Machol
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
| | - Lisa Emrick
- Texas Children's Hospital, Houston, Texas, USA
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, Texas, USA
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
- Joint BCM-CUHK Center of Medical Genetics, Prince of Wales Hospital, Hong Kong SAR, China
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Baldo MS, Nogueira C, Pereira C, Janeiro P, Ferreira S, Lourenço CM, Bandeira A, Martins E, Magalhães M, Rodrigues E, Santos H, Ferreira AC, Vilarinho L. Leigh Syndrome Spectrum: A Portuguese Population Cohort in an Evolutionary Genetic Era. Genes (Basel) 2023; 14:1536. [PMID: 37628588 PMCID: PMC10454233 DOI: 10.3390/genes14081536] [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: 06/26/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
Mitochondrial diseases are the most common inherited inborn error of metabolism resulting in deficient ATP generation, due to failure in homeostasis and proper bioenergetics. The most frequent mitochondrial disease manifestation in children is Leigh syndrome (LS), encompassing clinical, neuroradiological, biochemical, and molecular features. It typically affects infants but occurs anytime in life. Considering recent updates, LS clinical presentation has been stretched, and is now named LS spectrum (LSS), including classical LS and Leigh-like presentations. Apart from clinical diagnosis challenges, the molecular characterization also progressed from Sanger techniques to NGS (next-generation sequencing), encompassing analysis of nuclear (nDNA) and mitochondrial DNA (mtDNA). This upgrade resumed steps and favored diagnosis. Hereby, our paper presents molecular and clinical data on a Portuguese cohort of 40 positive cases of LSS. A total of 28 patients presented mutation in mtDNA and 12 in nDNA, with novel mutations identified in a heterogeneous group of genes. The present results contribute to the better knowledge of the molecular basis of LS and expand the clinical spectrum associated with this syndrome.
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Affiliation(s)
- Manuela Schubert Baldo
- Research and Development Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal; (M.S.B.)
| | - Célia Nogueira
- Research and Development Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal; (M.S.B.)
- Neonatal Screening, Metabolism and Genetics Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal
| | - Cristina Pereira
- Research and Development Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal; (M.S.B.)
- Neonatal Screening, Metabolism and Genetics Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal
| | - Patrícia Janeiro
- Inherited Metabolic Disease Reference Center, Lisbon North University Hospital Center (CHULN), EPE, 1649-028 Lisbon, Portugal
| | - Sara Ferreira
- Inherited Metabolic Disease Reference Center, Pediatric Hospital, Hospital and University Center of Coimbra, 3004-561 Coimbra, Portugal
| | - Charles M. Lourenço
- Neurogenetics Department, Faculdade de Medicina de São Jose do Rio Preto, São Jose do Rio Preto 15090-000, Brazil
| | - Anabela Bandeira
- Oporto Hospital Centre, University of Porto, 4099-001 Porto, Portugal
| | - Esmeralda Martins
- Oporto Hospital Centre, University of Porto, 4099-001 Porto, Portugal
- Unit for Multidisciplinary Research in Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, Porto University, 4050-313 Porto, Portugal
| | - Marina Magalhães
- Department of Neurology Porto Hospital and University Centre, EPE, 4050-011 Porto, Portugal
| | - Esmeralda Rodrigues
- Reference Center for Inherited Metabolic Disorders, University Hospital Centre S. João, 4200-319 Porto, Portugal
| | - Helena Santos
- Department of Pediatrics, Hospital Centre, EPE, 4434-502 Vila Nova de Gaia, Portugal
| | | | - Laura Vilarinho
- Research and Development Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal; (M.S.B.)
- Neonatal Screening, Metabolism and Genetics Unit, Human Genetics Department, National Institute of Health Doutor Ricardo Jorge, 4000-055 Porto, Portugal
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3
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Tise CG, Verscaj CP, Mendelsohn BA, Woods J, Lee CU, Enns GM, Stander Z, Hall PL, Cowan TM, Cusmano-Ozog KP. MT-ATP6 mitochondrial disease identified by newborn screening reveals a distinct biochemical phenotype. Am J Med Genet A 2023; 191:1492-1501. [PMID: 36883293 DOI: 10.1002/ajmg.a.63159] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/24/2023] [Accepted: 02/08/2023] [Indexed: 03/09/2023]
Abstract
Although decreased citrulline is used as a newborn screening (NBS) marker to identify proximal urea cycle disorders (UCDs), it is also a feature of some mitochondrial diseases, including MT-ATP6 mitochondrial disease. Here we describe biochemical and clinical features of 11 children born to eight mothers from seven separate families who were identified with low citrulline by NBS (range 3-5 μM; screening cutoff >5) and ultimately diagnosed with MT-ATP6 mitochondrial disease. Follow-up testing revealed a pattern of hypocitrullinemia together with elevated propionyl-(C3) and 3-hydroxyisovaleryl-(C5-OH) acylcarnitines, and a homoplasmic pathogenic variant in MT-ATP6 in all cases. Single and multivariate analysis of NBS data from the 11 cases using Collaborative Laboratory Integrated Reports (CLIR; https://clir.mayo.edu) demonstrated citrulline <1st percentile, C3 > 50th percentile, and C5-OH >90th percentile when compared with reference data, as well as unequivocal separation from proximal UCD cases and false-positive low citrulline cases using dual scatter plots. Five of the eight mothers were symptomatic at the time of their child(ren)'s diagnosis, and all mothers and maternal grandmothers evaluated molecularly and biochemically had a homoplasmic pathogenic variant in MT-ATP6, low citrulline, elevated C3, and/or elevated C5-OH. All molecularly confirmed individuals (n = 17) with either no symptoms (n = 12), migraines (n = 1), or a neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP) phenotype (n = 3) were found to have an A or U mitochondrial haplogroup, while one child with infantile-lethal Leigh syndrome had a B haplogroup.
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Affiliation(s)
- Christina G Tise
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Courtney P Verscaj
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Bryce A Mendelsohn
- Department of Medical Genetics, Kaiser Permanente Northern California, Oakland, California, USA
| | - Jeremy Woods
- Division of Medical Genetics, Stanford University, Stanford, California, USA.,Department of Medical Genetics and Metabolism, Valley Children's Healthcare, Madera, California, USA
| | - Chung U Lee
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Gregory M Enns
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Zinandré Stander
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Patricia L Hall
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Tina M Cowan
- Department of Pathology, Stanford University, Stanford, California, USA
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Leigh Syndrome: Spectrum of Molecular Defects and Clinical Features in Russia. Int J Mol Sci 2023; 24:ijms24021597. [PMID: 36675121 PMCID: PMC9865855 DOI: 10.3390/ijms24021597] [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: 12/05/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/15/2023] Open
Abstract
Leigh syndrome (LS), also known as infantile subacute necrotizing encephalopathy, is the most frequent mitochondrial disorder in children. Recently, more than 80 genes have been associated with LS, which greatly complicates the diagnosis. In this article, we present clinical and molecular findings of 219 patients with LS and give the detailed description of three cases with rare findings in nuclear genes MORC2, NARS2 and VPS13D, demonstrating wide genetic heterogeneity of this mitochondrial disease. The most common cause of LS in Russian patients are pathogenic variants in the SURF1 gene (44.3% of patients). The most frequent pathogenic variant is c.845_846delCT (66.0% of mutant alleles; 128/192), which is also widespread in Eastern Europe. Five main LS genes, SURF1, SCO2, MT-ATP6, MT-ND5 and PDHA1, account for 70% of all LS cases in the Russian Federation. Using next generation sequencing (NGS) technique, we were able to detect pathogenic variants in other nuclear genes: NDUFV1, NDUFS2, NDUFS8, NDUFAF5, NDUFAF6, NDUFA10, SUCLG1, GFM2, COX10, PMPCB, NARS2, PDHB and SLC19A3, including two genes previously associated with Leigh-like phenotypes-MORC2 and VPS13D. We found 49 previously undescribed nucleotide variants, including two deep intronic variants which affect splicing.
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Dambrova M, Makrecka-Kuka M, Kuka J, Vilskersts R, Nordberg D, Attwood MM, Smesny S, Sen ZD, Guo AC, Oler E, Tian S, Zheng J, Wishart DS, Liepinsh E, Schiöth HB. Acylcarnitines: Nomenclature, Biomarkers, Therapeutic Potential, Drug Targets, and Clinical Trials. Pharmacol Rev 2022; 74:506-551. [PMID: 35710135 DOI: 10.1124/pharmrev.121.000408] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acylcarnitines are fatty acid metabolites that play important roles in many cellular energy metabolism pathways. They have historically been used as important diagnostic markers for inborn errors of fatty acid oxidation and are being intensively studied as markers of energy metabolism, deficits in mitochondrial and peroxisomal β -oxidation activity, insulin resistance, and physical activity. Acylcarnitines are increasingly being identified as important indicators in metabolic studies of many diseases, including metabolic disorders, cardiovascular diseases, diabetes, depression, neurologic disorders, and certain cancers. The US Food and Drug Administration-approved drug L-carnitine, along with short-chain acylcarnitines (acetylcarnitine and propionylcarnitine), is now widely used as a dietary supplement. In light of their growing importance, we have undertaken an extensive review of acylcarnitines and provided a detailed description of their identity, nomenclature, classification, biochemistry, pathophysiology, supplementary use, potential drug targets, and clinical trials. We also summarize these updates in the Human Metabolome Database, which now includes information on the structures, chemical formulae, chemical/spectral properties, descriptions, and pathways for 1240 acylcarnitines. This work lays a solid foundation for identifying, characterizing, and understanding acylcarnitines in human biosamples. We also discuss the emerging opportunities for using acylcarnitines as biomarkers and as dietary interventions or supplements for many wide-ranging indications. The opportunity to identify new drug targets involved in controlling acylcarnitine levels is also discussed. SIGNIFICANCE STATEMENT: This review provides a comprehensive overview of acylcarnitines, including their nomenclature, structure and biochemistry, and use as disease biomarkers and pharmaceutical agents. We present updated information contained in the Human Metabolome Database website as well as substantial mapping of the known biochemical pathways associated with acylcarnitines, thereby providing a strong foundation for further clarification of their physiological roles.
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Affiliation(s)
- Maija Dambrova
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Marina Makrecka-Kuka
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Janis Kuka
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Reinis Vilskersts
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Didi Nordberg
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Misty M Attwood
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Stefan Smesny
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Zumrut Duygu Sen
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - An Chi Guo
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Eponine Oler
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Siyang Tian
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Jiamin Zheng
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - David S Wishart
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Edgars Liepinsh
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Helgi B Schiöth
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
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Dawod PGA, Jancic J, Marjanovic A, Brankovic M, Jankovic M, Samardzic J, Gamil Anwar Dawod A, Novakovic I, Abdel Motaleb FI, Radlovic V, Kostic VS, Nikolic D. Mutational Analysis and mtDNA Haplogroup Characterization in Three Serbian Cases of Mitochondrial Encephalomyopathies and Literature Review. Diagnostics (Basel) 2021; 11:1969. [PMID: 34829316 PMCID: PMC8620769 DOI: 10.3390/diagnostics11111969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial encephalomyopathies (MEMP) are heterogeneous multisystem disorders frequently associated with mitochondrial DNA (mtDNA) mutations. Clinical presentation varies considerably in age of onset, course, and severity up to death in early childhood. In this study, we performed molecular genetic analysis for mtDNA pathogenic mutation detection in Serbian children, preliminary diagnosed clinically, biochemically and by brain imaging for mitochondrial encephalomyopathies disorders. Sanger sequencing analysis in three Serbian probands revealed two known pathogenic mutations. Two probands had a heteroplasmic point mutation m.3243A>G in the MT-TL1 gene, which confirmed mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode syndrome (MELAS), while a single case clinically manifested for Leigh syndrome had an almost homoplasmic (close to 100%) m.8993T>G mutation in the MT-ATP6 gene. After full mtDNA MITOMASTER analysis and PhyloTree build 17, we report MELAS' association with haplogroups U and H (U2e and H15 subclades); likewise, the mtDNA-associated Leigh syndrome proband shows a preference for haplogroup H (H34 subclade). Based on clinical-genetic correlation, we suggest that haplogroup H may contribute to the mitochondrial encephalomyopathies' phenotypic variability of the patients in our study. We conclude that genetic studies for the distinctive mitochondrial encephalomyopathies should be well-considered for realizing clinical severity and possible outcomes.
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Affiliation(s)
- Phepy G. A. Dawod
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt;
| | - Jasna Jancic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Clinic of Neurology and Psychiatry of Children and Youth, 11000 Belgrade, Serbia
| | - Ana Marjanovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
| | - Marija Brankovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
| | - Milena Jankovic
- Neurology Clinic, Clinical Center of Serbia, 11000 Belgrade, Serbia;
| | - Janko Samardzic
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;
| | - Ayman Gamil Anwar Dawod
- Internal Medicine, Hepatogastroenterology and Endoscopy Department, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt;
| | - Ivana Novakovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
| | - Fayda I. Abdel Motaleb
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt;
| | - Vladimir Radlovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Pediatric Surgery Department, University Children’s Hospital, 11000 Belgrade, Serbia
| | - Vladimir S. Kostic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Neurology Clinic, Clinical Center of Serbia, 11000 Belgrade, Serbia;
| | - Dejan Nikolic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Physical Medicine and Rehabilitation Department, University Children’s Hospital, Tirsova 10, 11000 Belgrade, Serbia
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7
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Peretz RH, Ah Mew N, Vernon HJ, Ganetzky RD. Prospective diagnosis of MT-ATP6-related mitochondrial disease by newborn screening. Mol Genet Metab 2021; 134:37-42. [PMID: 34176718 PMCID: PMC8578202 DOI: 10.1016/j.ymgme.2021.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 11/24/2022]
Abstract
Elevated citrulline and C5-OH levels are reported as part of the newborn screening of core and secondary disorders on the Recommended Uniform Screening Panel (RUSP). Additionally, some state laboratory newborn screening programs report low citrulline levels, which may be observed in proximal urea cycle disorders. We report six patients who were found on newborn screening to have low citrulline and/or elevated C5-OH levels in whom confirmatory testing showed the combination of these two abnormal analytes. Mitochondrial sequencing revealed known pathogenic variants in MT-ATP6 at high heteroplasmy levels in all cases. MT-ATP6 at these heteroplasmy levels is associated with Leigh syndrome, a progressive neurodegenerative disease. Patients were treated with supplemental citrulline and, in some cases, mitochondrial cofactor therapy. These six patients have not experienced metabolic crises or developmental regression, and early diagnosis and management may help prevent the neurological sequelae of Leigh syndrome. The affected mothers and siblings are asymptomatic or paucisymptomatic (e.g. intellectual disability, depression, migraines, obsessive-compulsive disorder, and poor balance) despite high heteroplasmy or apparent homoplasmy of the familial variant, thus expanding the clinical spectrum seen in pathogenic variants of MT-ATP6. Confirmatory plasma amino acid analysis and acylcarnitine profiling should be ordered in a patient with either low citrulline and/or elevated C5-OH, as this combination appears specific for pathogenic variants in MT-ATP6.
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Affiliation(s)
- Ryan H Peretz
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Nicholas Ah Mew
- Rare Disease Institute, Children's National Hospital, Washington, DC, United States
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Rebecca D Ganetzky
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States.
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8
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Mani S. Response to "Letter to the editors" in regard to the article 'Genetic heterogeneity of mitochondrial genome in thiamine deficient Leigh syndrome patients'. J Neurol Sci 2019; 407:116441. [PMID: 31627180 DOI: 10.1016/j.jns.2019.116441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 10/26/2022]
Affiliation(s)
- Shalini Mani
- Centre for emerging diseases, Departmenmt of Biotechnology, Jaypee Institute of Information Technology, A-10, Sector 62, Noida 201301, India.
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9
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WU D, LU B, YANG J, YANG R, HUANG X, TONG F, ZHENG J, ZHAO Z. [Genetic analysis of newborns with abnormal metabolism of 3-hydroxyisovalerylcarnitine]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2019; 48:390-396. [PMID: 31901042 PMCID: PMC8800779 DOI: 10.3785/j.issn.1008-9292.2019.08.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/04/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To investigate the genetic characterization of 3-hydroxyisovalerylcarnitine (C5-OH) metabolic abnormality in neonates. METHODS Fifty two newborns with increased C5-OH, C5-OH/C3 and C5-OH/C8 detected by tandem mass spectrometry during neonatal screening were enrolled in the study. Genomic DNA was extracted from the whole blood samples of 52 cases and their parents. Seventy-nine genes associated with genetic and metabolic diseases including MCCC1, MCCC2 were targeted by liquid capture technique. Variation information of these genes was examined by high-throughput sequencing and bioinformatic analysis, and then was classified based on the American College of Medical Genetics and Genomics (ACMG) standards and guidelines. The genetic types were classified as wild-type, MCCC1-maternal-mutation, MCCC1-paternal-mutation and MCCC2-mutation. Wilcoxon rank-sum test was performed for the increased multiples of C5-OH calculated in neonatal screening. RESULTS Twenty one MCCC1 variants (14 novel) were identified in 37 cases, 6 MCCC2 variants (5 novel) in 4 cases. The increased multiple of C5-OH calculated in MCCC1-maternal-mutation and MCCC2-mutation groups were significantly higher than that in wild-type group (all P<0.05), while there was no significant difference between MCCC1-paternal-mutation group and wild-type group (P>0.05). CONCLUSIONS Mutations on MCCC1 and MCCC2 genes are the major genetic causes for the increased C5-OH in neonates, and maternal single heterozygous mutation can contribute to the moderately to severely increased C5-OH.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhengyan ZHAO
- 赵正言(1953—), 男, 硕士, 教授, 博士生导师, 主要从事遗传代谢病和儿童保健学研究; E-mail:
;
https://orcid.org/0000-0001-8626-2578
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10
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Recent topics: the diagnosis, molecular genesis, and treatment of mitochondrial diseases. J Hum Genet 2018; 64:113-125. [PMID: 30459337 DOI: 10.1038/s10038-018-0528-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 12/30/2022]
Abstract
Mitochondrial diseases are inherited metabolic diseases based on disorders of energy production. The expansion of exome analyses has led to the discovery of many pathogenic nuclear genes associated with these diseases, and research into the pathogenesis of metabolic diseases has progressed. In cases of Leigh syndrome, it is desirable to perform both biochemical and genetic analyses, and pathogenic gene mutations have been identified in over half of the cases analyzed this way. Tandem mass screening and organic acid analyses of urine can sometimes provide important information that leads to the identification of pathogenic genes. Our comprehensive gene analyses have led to the discovery of several novel genes for mitochondrial diseases. Indeed, we reported that GTPBP3 and QRSL1 are involved in mitochondrial DNA maturation. In 2017, as a result of international collaboration, we also identified that mutations in ATAD3 and C1QBP cause mitochondrial disease. Given the varied pathogeneses, treatments for mitochondrial diseases should be specifically tailored to the mutated gene. Clinical trials of sodium pyruvate, 5-aminolevulinic acid with sodium ferrous citrate, and taurine as a treatment for mitochondrial disease have begun in Japan. Given that some mitochondrial diseases may respond well to certain treatments if the pathogenic gene can be identified, an early genetic diagnosis is crucial. Additionally, in Japan, prenatal diagnoses for mitochondrial diseases caused by nuclear genes have been achieved for genes shown to be pathogenic. Treatment and management approaches, including prenatal diagnoses, specifically tailored to the various phenotypes and pathologies of mitochondrial diseases are expected to become increasingly available.
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11
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Vaccination triggering onset of m.8993T > G associated Leigh syndrome. Mol Genet Metab Rep 2018; 15:127-128. [PMID: 30023303 PMCID: PMC6047472 DOI: 10.1016/j.ymgmr.2018.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 11/21/2022] Open
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12
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van Karnebeek CDM, Wortmann SB, Tarailo-Graovac M, Langeveld M, Ferreira CR, van de Kamp JM, Hollak CE, Wasserman WW, Waterham HR, Wevers RA, Haack TB, Wanders RJA, Boycott KM. The role of the clinician in the multi-omics era: are you ready? J Inherit Metab Dis 2018; 41:571-582. [PMID: 29362952 PMCID: PMC5959952 DOI: 10.1007/s10545-017-0128-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/10/2017] [Accepted: 12/12/2017] [Indexed: 12/11/2022]
Abstract
Since Garrod's first description of alkaptonuria in 1902, and newborn screening for phenylketonuria introduced in the 1960s, P4 medicine (preventive, predictive, personalized, and participatory) has been a reality for the clinician serving patients with inherited metabolic diseases. The era of high-throughput technologies promises to accelerate its scale dramatically. Genomics, transcriptomics, epigenomics, proteomics, glycomics, metabolomics, and lipidomics offer an amazing opportunity for holistic investigation and contextual pathophysiologic understanding of inherited metabolic diseases for precise diagnosis and tailored treatment. While each of the -omics technologies is important to systems biology, some are more mature than others. Exome sequencing is emerging as a reimbursed test in clinics around the world, and untargeted metabolomics has the potential to serve as a single biochemical testing platform. The challenge lies in the integration and cautious interpretation of these big data, with translation into clinically meaningful information and/or action for our patients. A daunting but exciting task for the clinician; we provide clinical cases to illustrate the importance of his/her role as the connector between physicians, laboratory experts and researchers in the basic, computer, and clinical sciences. Open collaborations, data sharing, functional assays, and model organisms play a key role in the validation of -omics discoveries. Having all the right expertise at the table when discussing the diagnostic approach and individualized management plan according to the information yielded by -omics investigations (e.g., actionable mutations, novel therapeutic interventions), is the stepping stone of P4 medicine. Patient participation and the adjustment of the medical team's plan to his/her and the family's wishes most certainly is the capstone. Are you ready?
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Affiliation(s)
- Clara D M van Karnebeek
- Department of Pediatrics and Clinical Genetics, Academic Medical Centre, Amsterdam, The Netherlands.
- Departments of Pediatrics, Centre for Molecular Medicine and Therapeutics, BC Children's Research Institute, University of British Columbia, Vancouver, BC, Canada.
- Deparment of Pediatrics (Room H7-224), Emma Children's Hospital, Academic Medical Centre, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
| | - Saskia B Wortmann
- Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg, Austria
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Maja Tarailo-Graovac
- Departments of Pediatrics, Centre for Molecular Medicine and Therapeutics, BC Children's Research Institute, University of British Columbia, Vancouver, BC, Canada
- Departments of Medical Genetics, Centre for Molecular Medicine and Therapeutics, BC Children's Research Institute, Vancouver, BC, Canada
- Departments of Biochemistry, Molecular Biology, and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, CA, Canada
| | - Mirjam Langeveld
- Department of Endocrinology and Metabolism, Academic Medical Centre, Amsterdam, The Netherlands
| | - Carlos R Ferreira
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jiddeke M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Carla E Hollak
- Department of Endocrinology and Metabolism, Academic Medical Centre, Amsterdam, The Netherlands
| | - Wyeth W Wasserman
- Departments of Pediatrics, Centre for Molecular Medicine and Therapeutics, BC Children's Research Institute, University of British Columbia, Vancouver, BC, Canada
- Departments of Medical Genetics, Centre for Molecular Medicine and Therapeutics, BC Children's Research Institute, Vancouver, BC, Canada
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Laboratory Division & Department of Pediatrics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Ron A Wevers
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Laboratory Division & Department of Pediatrics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
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13
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Ganetzky RD, Falk MJ. 8-year retrospective analysis of intravenous arginine therapy for acute metabolic strokes in pediatric mitochondrial disease. Mol Genet Metab 2018; 123:301-308. [PMID: 29428506 PMCID: PMC5849405 DOI: 10.1016/j.ymgme.2018.01.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 01/31/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Intravenous (IV) arginine has been reported to ameliorate acute metabolic stroke symptoms in adult patients with Mitochondrial Encephalopathy with Lactic Acidosis and Stroke-like Episodes (MELAS) syndrome, where its therapeutic benefit is postulated to result from arginine acting as a nitric oxide donor to reverse vasospasm. Further, reduced plasma arginine may occur in mitochondrial disease since the biosynthesis of arginine's precursor, citrulline, requires ATP. Metabolic strokes occur across a wide array of primary mitochondrial diseases having diverse molecular etiologies that are likely to share similar pathophysiologic mechanisms. Therefore, IV arginine has been increasingly used for the acute clinical treatment of metabolic stroke across a broad mitochondrial disease population. METHODS We performed retrospective analysis of a large cohort of subjects who were under 18 years of age at IRB #08-6177 study enrollment and had molecularly-confirmed primary mitochondrial disease (n = 71, excluding the common MELAS m.3243A>G mutation). 9 unrelated subjects in this cohort received acute arginine IV treatment for one or more stroke-like episodes (n = 17 total episodes) between 2009 and 2016 at the Children's Hospital of Philadelphia. Retrospectively reviewed data included subject genotype, clinical symptoms, age, arginine dosing, neuroimaging (if performed), prophylactic therapies, and adverse events. RESULTS Genetic etiologies of subjects who presented with acute metabolic strokes included 4 mitochondrial DNA (mtDNA) pathogenic point mutations, 1 mtDNA deletion, and 4 nuclear gene disorders. Subject age ranged from 19 months to 23 years at the time of any metabolic stroke episode (median, 8 years). 3 subjects had recurrent stroke episodes. 70% of subjects were on prophylactic arginine or citrulline therapy at the time of a stroke-like episode. IV arginine was initiated on initial presentation in 65% of cases. IV arginine was given for 1-7 days (median, 1 day). A positive clinical response to IV arginine occurred in 47% of stroke-like episodes; an additional 6% of episodes showed clinical benefit from multiple simultaneous treatments that included arginine, confounding sole interpretation of arginine effect. All IV arginine-responsive stroke-like episodes (n = 8) received treatment immediately on presentation (p = .003). Interestingly, the presence of unilateral symptoms strongly predicted arginine response (p = .02, Chi-Square); however, almost all of these cases immediately received IV arginine, confounding interpretation of causality direction. Suggestive trends toward increased IV arginine response were seen in subjects with mtDNA relative to nDNA mutations and in older pediatric subjects, although statistical significance was not reached possibly due to small sample size. No adverse events, including hypotensive episodes, from IV arginine therapy were reported. CONCLUSIONS Single-center retrospective analysis suggests that IV arginine therapy yields significant therapeutic benefit with little risk in pediatric mitochondrial disease stroke subjects across a wide range of genetic etiologies beyond classical MELAS. Acute hemiplegic stroke, in particular, was highly responsive to IV arginine treatment. Prospective studies with consistent arginine dosing, and pre- and post-neuroimaging, will further inform the clinical utility of IV arginine therapy for acute metabolic stroke in pediatric mitochondrial disease.
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Affiliation(s)
- Rebecca D Ganetzky
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marni J Falk
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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14
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Larson AA, Balasubramaniam S, Christodoulou J, Burrage LC, Marom R, Graham BH, Diaz GA, Glamuzina E, Hauser N, Heese B, Horvath G, Mattman A, van Karnebeek C, Lane Rutledge S, Williamson A, Estrella L, Van Hove JKL, Weisfeld-Adams JD. Biochemical signatures mimicking multiple carboxylase deficiency in children with mutations in MT-ATP6. Mitochondrion 2018; 44:58-64. [PMID: 29307858 DOI: 10.1016/j.mito.2018.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 11/21/2017] [Accepted: 01/03/2018] [Indexed: 12/13/2022]
Abstract
Elevations of specific acylcarnitines in blood reflect carboxylase deficiencies, and have utility in newborn screening for life-threatening organic acidemias and other inherited metabolic diseases. In this report, we describe a newly-identified association of biochemical features of multiple carboxylase deficiency in individuals harboring mitochondrial DNA (mtDNA) mutations in MT-ATP6 and in whom organic acidemias and multiple carboxylase deficiencies were excluded. Using retrospective chart review, we identified eleven individuals with abnormally elevated propionylcarnitine (C3) or hydroxyisovalerylcarnitine (C5OH) with mutations in MT-ATP6, most commonly m.8993T>G in high heteroplasmy or homoplasmy. Most patients were ascertained on newborn screening; most had normal enzymatic or molecular genetic testing to exclude biotinidase and holocarboxylase synthetase deficiencies. MT-ATP6 is associated with some cases of Leigh disease; clinical outcomes in our cohort ranged from death from neurodegenerative disease in early childhood to clinically and developmentally normal after several years of follow-up. These cases expand the biochemical phenotype associated with MT-ATP6 mutations, especially m.8993T>G, to include acylcarnitine abnormalities mimicking carboxylase deficiency states. Clinicians should be aware of this association and its implications for newborn screening, and consider mtDNA sequencing in patients exhibiting similar acylcarnitine abnormalities that are biotin-unresponsive and in whom other enzymatic deficiencies have been excluded.
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Affiliation(s)
- Austin A Larson
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA; Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, CO, USA.
| | - Shanti Balasubramaniam
- Princess Margaret Hospital for Children, Perth, Australia; Children's Hospital at Westmead, Sydney, Australia
| | - John Christodoulou
- Neurodevelopmental Genomics Research Group, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - George A Diaz
- Program for Inherited Metabolic Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Emma Glamuzina
- Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
| | - Natalie Hauser
- Inherited Metabolic Diseases Clinic, Valley Children's Hospital, Madera, CA, USA
| | - Bryce Heese
- Children's Mercy Hospitals and Clinics, Kansas City, MO, USA
| | - Gabriella Horvath
- Inherited Metabolic Diseases Clinic, University of British Columbia, Vancouver, Canada
| | - Andre Mattman
- Inherited Metabolic Diseases Clinic, University of British Columbia, Vancouver, Canada
| | - Clara van Karnebeek
- Inherited Metabolic Diseases Clinic, University of British Columbia, Vancouver, Canada; Centre for Molecular Medicine and Therapeutics, Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - S Lane Rutledge
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Amy Williamson
- Program for Inherited Metabolic Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lissette Estrella
- Program for Inherited Metabolic Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Johan K L Van Hove
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA; Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, CO, USA
| | - James D Weisfeld-Adams
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA; Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, CO, USA
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