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Gouiza I, Hechmi M, Zioudi A, Dallali H, Kheriji N, Charif M, Le Mao M, Galai S, Kraoua L, Ben Youssef-Turki I, Kraoua I, Lenaers G, Kefi R. Expanding the genetic spectrum of mitochondrial diseases in Tunisia: novel variants revealed by whole-exome sequencing. Front Genet 2024; 14:1259826. [PMID: 38283147 PMCID: PMC10811255 DOI: 10.3389/fgene.2023.1259826] [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: 07/16/2023] [Accepted: 12/22/2023] [Indexed: 01/30/2024] Open
Abstract
Introduction: Inherited mitochondrial diseases are the most common group of metabolic disorders caused by a defect in oxidative phosphorylation. They are characterized by a wide clinical and genetic spectrum and can manifest at any age. In this study, we established novel phenotype-genotype correlations between the clinical and molecular features of a cohort of Tunisian patients with mitochondrial diseases. Materials and methods: Whole-exome sequencing was performed on five Tunisian patients with suspected mitochondrial diseases. Then, a combination of filtering and bioinformatics prediction tools was utilized to assess the pathogenicity of genetic variations. Sanger sequencing was subsequently performed to confirm the presence of potential deleterious variants in the patients and verify their segregation within families. Structural modeling was conducted to study the effect of novel variants on the protein structure. Results: We identified two novel homozygous variants in NDUFAF5 (c.827G>C; p.Arg276Pro) and FASTKD2 (c.496_497del; p.Leu166GlufsTer2) associated with a severe clinical form of Leigh and Leigh-like syndromes, respectively. Our results further disclosed two variants unreported in North Africa, in GFM2 (c.569G>A; p.Arg190Gln) and FOXRED1 (c.1261G>A; p.Val421Met) genes, and we described the first case of fumaric aciduria in a Tunisian patient harboring the c.1358T>C; p.Leu453Pro FH variant. Conclusion: Our study expands the mutational and phenotypic spectrum of mitochondrial diseases in Tunisia and highlights the importance of next-generation sequencing to decipher the pathomolecular mechanisms responsible for these disorders in an admixed population.
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Affiliation(s)
- Ismail Gouiza
- University of Angers, MitoLab Team, Unité MitoVasc, UMR CNRS (Unité mixte de recherche Centre national de la recherche scientifique) 6015 INSERM (Institut national de la santé et de la recherche médicale) U1083, SFR ICAT, University of Angers, Angers, France
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Tunis, Tunisia
- Tunis El Manar University, Tunis, Tunisia
- Faculty of Medicine of Tunis, Tunis, Tunisia
| | - Meriem Hechmi
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Tunis, Tunisia
- Tunis El Manar University, Tunis, Tunisia
| | - Abir Zioudi
- Tunis El Manar University, Tunis, Tunisia
- Faculty of Medicine of Tunis, Tunis, Tunisia
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia
| | - Hamza Dallali
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Tunis, Tunisia
- Tunis El Manar University, Tunis, Tunisia
| | - Nadia Kheriji
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Tunis, Tunisia
- Tunis El Manar University, Tunis, Tunisia
- Faculty of Medicine of Tunis, Tunis, Tunisia
| | - Majida Charif
- Genetics and Immuno-Cell Therapy Team, Mohammed First University, Oujda, Morocco
| | - Morgane Le Mao
- University of Angers, MitoLab Team, Unité MitoVasc, UMR CNRS (Unité mixte de recherche Centre national de la recherche scientifique) 6015 INSERM (Institut national de la santé et de la recherche médicale) U1083, SFR ICAT, University of Angers, Angers, France
| | - Said Galai
- Faculty of Medicine of Tunis, Tunis, Tunisia
- Department of Clinical Biology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia
| | - Lilia Kraoua
- Tunis El Manar University, Tunis, Tunisia
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
| | - Ilhem Ben Youssef-Turki
- Tunis El Manar University, Tunis, Tunisia
- Faculty of Medicine of Tunis, Tunis, Tunisia
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia
| | - Ichraf Kraoua
- Tunis El Manar University, Tunis, Tunisia
- Faculty of Medicine of Tunis, Tunis, Tunisia
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia
| | - Guy Lenaers
- University of Angers, MitoLab Team, Unité MitoVasc, UMR CNRS (Unité mixte de recherche Centre national de la recherche scientifique) 6015 INSERM (Institut national de la santé et de la recherche médicale) U1083, SFR ICAT, University of Angers, Angers, France
- Department of Neurology, CHU d’Angers, Angers, France
| | - Rym Kefi
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Tunis, Tunisia
- Tunis El Manar University, Tunis, Tunisia
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2
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Vieira P, Nagy II, Rahikkala E, Väisänen ML, Latva K, Kaunisto K, Valmari P, Keski-Filppula R, Haanpää MK, Sidoroff V, Miettinen PJ, Arkkola T, Ojaniemi M, Nuutinen M, Uusimaa J, Myllynen P. Cytosolic phosphoenolpyruvate carboxykinase deficiency: Expanding the clinical phenotype and novel laboratory findings. J Inherit Metab Dis 2022; 45:223-234. [PMID: 34622459 DOI: 10.1002/jimd.12446] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 10/04/2021] [Accepted: 10/06/2021] [Indexed: 11/11/2022]
Abstract
Cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) deficiency due to the homozygous PCK1 variant has recently been associated with childhood-onset hypoglycemia with a recognizable pattern of abnormal urine organic acids. In this study, 21 children and 3 adult patients with genetically confirmed PEPCK-C deficiency were diagnosed during the years 2016 to 2019 and the available biochemical and clinical data were collected. All patients were ethnic Finns. Most patients (22 out of 24) had a previously published homozygous PCK1 variant c.925G>A. Two patients had a novel compound heterozygous PCK1 variant c.925G>A and c.716C>T. The laboratory results showed abnormal urine organic acid profile with increased tricarboxylic acid cycle intermediates and inadequate ketone body production during hypoglycemia. The hypoglycemic episodes manifested predominantly in the morning. Infections, fasting or poor food intake, heavy exercise, alcohol consumption, and breastfeeding were identified as triggering factors. Five patients presented with neonatal hypoglycemia. Hypoglycemic seizures occurred in half of the patients (12 out of 24). The first hypoglycemic episode often occurred at the age of 1-2 years, but it sometimes presented at a later age, and could re-occur during school age or adulthood. This study adds to the laboratory data on PEPCK-C deficiency, confirming the recognizable urine organic acid pattern and identifying deficient ketogenesis as a novel laboratory finding. The phenotype is expanded suggesting that the risk of hypoglycemia may continue into adulthood if predisposing factors are present.
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Affiliation(s)
- Päivi Vieira
- Clinic for Children and Adolescents, Oulu University Hospital, Oulu, Finland
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Irina I Nagy
- Department of Clinical Chemistry, Cancer and Translational Medicine Research Unit, Medical Research Center, University of Oulu and Northern Finland Laboratory Centre NordLab, Oulu University Hospital, Oulu, Finland
| | - Elisa Rahikkala
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
- Department of Clinical Genetics, Oulu University Hospital, Oulu, Finland
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Marja-Leena Väisänen
- Department of Clinical Chemistry, Cancer and Translational Medicine Research Unit, Medical Research Center, University of Oulu and Northern Finland Laboratory Centre NordLab, Oulu University Hospital, Oulu, Finland
| | - Katariina Latva
- Department of Pediatrics, Päijät-Häme Central Hospital, Lahti, Finland
| | - Kari Kaunisto
- Clinic for Children and Adolescents, Oulu University Hospital, Oulu, Finland
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Pekka Valmari
- Department of Pediatrics, Lapland Central Hospital, Rovaniemi, Finland
| | - Riikka Keski-Filppula
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
- Department of Clinical Genetics, Oulu University Hospital, Oulu, Finland
| | - Maria K Haanpää
- Institute of Biomedicine, University of Turku, Turku, Finland
- Department of Clinical Genetics, Turku University Hospital and University of Turku, Turku, Finland
| | - Virpi Sidoroff
- Department of Pediatrics, North Karelia Central Hospital, Joensuu, Finland
| | - Päivi J Miettinen
- New Children's Hospital, Helsinki University Hospital, Pediatric Research Center, Helsinki, Finland
| | - Tuula Arkkola
- Clinic for Children and Adolescents, Oulu University Hospital, Oulu, Finland
| | - Marja Ojaniemi
- Clinic for Children and Adolescents, Oulu University Hospital, Oulu, Finland
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Matti Nuutinen
- Clinic for Children and Adolescents, Oulu University Hospital, Oulu, Finland
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Johanna Uusimaa
- Clinic for Children and Adolescents, Oulu University Hospital, Oulu, Finland
- PEDEGO Research Unit and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Päivi Myllynen
- Department of Clinical Chemistry, Cancer and Translational Medicine Research Unit, Medical Research Center, University of Oulu and Northern Finland Laboratory Centre NordLab, Oulu University Hospital, Oulu, Finland
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3
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Kamihara J, Horton C, Tian Y, Zhou J, Richardson M, LaDuca H, Rana HQ. Different Fumarate Hydratase Gene Variants Are Associated With Distinct Cancer Phenotypes. JCO Precis Oncol 2022; 5:1568-1578. [PMID: 34994643 DOI: 10.1200/po.21.00263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Whether individuals with monoallelic FH pathogenic variants (PVs) associated with autosomal recessive fumarate hydratase (FH) deficiency are also at risk of autosomal dominant FH-associated tumors is of paramount clinical importance. METHODS A retrospective study of individuals with a PV in the FH gene identified via multigene panel testing from 2012 to 2019 through a single testing laboratory was performed. Cancer histories of individuals with PVs in FH (FH PV) were compared to those with PVs associated only with autosomal recessive FH deficiency (FH-d PV) and to FH-negative controls. Cancer histories of individuals with truncating versus nontruncating FH PV were also compared. RESULTS Individuals with FH PV were more likely to have kidney cancer than those with FH-d PV (odds ratio, 9.0; 95% CI, 4.4 to 20.0; P < .001) or FH-negative controls (odds ratio, 7.6; 95% CI, 5.2 to 11.2; P value < .001). The FH PV cohort had kidney cancer at a significantly younger age (median age: 35.0 years; interquartile range, 26.0-45.0 years) than the FH-d PV cohort (median age: 44.5 years; interquartile range, 43.5-53.5 years; P = .011). Within the FH PV cohort, there were no differences in the frequency or age at kidney cancer between those with truncating versus nontruncating PV. CONCLUSION Unlike FH PV, FH-d PV are not associated with kidney cancers at early ages of onset. The FH-d PV cohort had a cancer phenotype that resembled FH-negative controls. These data may inform genetic counseling and risk assessment of individuals with FH-d PV.
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Affiliation(s)
- Junne Kamihara
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, MA.,Division of Population Sciences, Dana-Farber Cancer Institute, Boston, MA.,Harvard Medical School, Boston, MA
| | | | | | | | | | | | - Huma Q Rana
- Division of Population Sciences, Dana-Farber Cancer Institute, Boston, MA.,Harvard Medical School, Boston, MA.,Division of Cancer Genetics and Prevention, Dana-Farber Cancer Institute, Boston, MA
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4
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Ticci C, Nesti C, Rubegni A, Doccini S, Baldacci J, Dal Canto F, Ragni L, Cordelli DM, Donati MA, Santorelli FM. Bi-allelic variants in MDH2: Expanding the clinical phenotype. Clin Genet 2021; 101:260-264. [PMID: 34766628 DOI: 10.1111/cge.14088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/29/2022]
Abstract
Bi-allelic alterations in the MDH2 gene have recently been reported in three unrelated toddlers with early-onset severe encephalopathy. Here, we describe a new case of a child carrying novel variants in MDH2. This child presented with early-onset encephalocardiopathy requiring heart transplant and showed cerebellar ataxia and drug-responsive epilepsy; his family history was significant for multiple cancers, a feature often associated with monoallelic variants in MDH2. Functional studies in cultured skin fibroblasts from the proband showed reduced protein levels and impaired enzyme activity, further corroborating the genetic results. The relatively mild neurological presentation and severe cardiac manifestations requiring heart transplant distinguish this case from previous reports. This patient thus expands the spectrum of clinical features associated with MDH2 variants.
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Affiliation(s)
- Chiara Ticci
- Metabolic Disease Unit, Meyer Children's Hospital, Florence, Italy
| | - Claudia Nesti
- IRCCS Stella Maris Foundation, Molecular Medicine for Neurodegenerative and Neuromuscular Disease Unit, Pisa, Italy
| | - Anna Rubegni
- IRCCS Stella Maris Foundation, Molecular Medicine for Neurodegenerative and Neuromuscular Disease Unit, Pisa, Italy
| | - Stefano Doccini
- IRCCS Stella Maris Foundation, Molecular Medicine for Neurodegenerative and Neuromuscular Disease Unit, Pisa, Italy
| | - Jacopo Baldacci
- IRCCS Stella Maris Foundation, Molecular Medicine for Neurodegenerative and Neuromuscular Disease Unit, Pisa, Italy
| | - Flavio Dal Canto
- IRCCS Stella Maris Foundation, Molecular Medicine for Neurodegenerative and Neuromuscular Disease Unit, Pisa, Italy
| | - Luca Ragni
- Paediatric Cardiology and ACHD Unit, S. Orsola Hospital, Bologna, Italy
| | - Duccio M Cordelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'età Pediatrica, Bologna, Italy
| | | | - Filippo M Santorelli
- IRCCS Stella Maris Foundation, Molecular Medicine for Neurodegenerative and Neuromuscular Disease Unit, Pisa, Italy
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5
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Jeong J, Lee J, Kim JH, Lim C. Metabolic flux from the Krebs cycle to glutamate transmission tunes a neural brake on seizure onset. PLoS Genet 2021; 17:e1009871. [PMID: 34714823 PMCID: PMC8555787 DOI: 10.1371/journal.pgen.1009871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 10/11/2021] [Indexed: 01/18/2023] Open
Abstract
Kohlschütter-Tönz syndrome (KTS) manifests as neurological dysfunctions, including early-onset seizures. Mutations in the citrate transporter SLC13A5 are associated with KTS, yet their underlying mechanisms remain elusive. Here, we report that a Drosophila SLC13A5 homolog, I'm not dead yet (Indy), constitutes a neurometabolic pathway that suppresses seizure. Loss of Indy function in glutamatergic neurons caused "bang-induced" seizure-like behaviors. In fact, glutamate biosynthesis from the citric acid cycle was limiting in Indy mutants for seizure-suppressing glutamate transmission. Oral administration of the rate-limiting α-ketoglutarate in the metabolic pathway rescued low glutamate levels in Indy mutants and ameliorated their seizure-like behaviors. This metabolic control of the seizure susceptibility was mapped to a pair of glutamatergic neurons, reversible by optogenetic controls of their activity, and further relayed onto fan-shaped body neurons via the ionotropic glutamate receptors. Accordingly, our findings reveal a micro-circuit that links neural metabolism to seizure, providing important clues to KTS-associated neurodevelopmental deficits.
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Affiliation(s)
- Jiwon Jeong
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jongbin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Ji-hyung Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
- * E-mail:
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6
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Peetsold M, Goorden S, Breuning M, Williams M, Bakker J, Jacobs E, Hussaarts-Odijk L, Peeters C. Fumarase Deficiency: A Case With a New Pathogenic Mutation and a Review of the Literature. J Child Neurol 2021; 36:310-323. [PMID: 33052056 DOI: 10.1177/0883073820962931] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fumarase deficiency (FD) is a rare and severe autosomal disorder, caused by inactivity of the enzyme fumarase, due to biallelic mutations of the fumarase hydratase (FH) gene. Several pathogenic mutations have been published. The article describes an infant with failure to thrive, microcephaly, axial hypotonia, and developmental retardation with increased excretion of fumarate, no activity of fumarase and a homozygous mutation of the FH gene, which was until recently only known as a variant of unknown significance. Carriers of pathogenic mutations in the FH gene are at risk for developing renal cell carcinoma and should therefore be screened. Both parents were healthy carriers of the mutation and had decreased levels of enzyme activity. In addition, the article presents an overview and analysis of all cases of FD reported thus far in the literature.
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Affiliation(s)
- Marieke Peetsold
- Department of Pediatrics, 72471Alrijne Medical Center, Leiderdorp, the Netherlands
| | - Susan Goorden
- Laboratory Genetic Metabolic Disease, 26066Academic Medical Center, University of Amsterdam, the Netherlands
| | - Martijn Breuning
- Department of Clinical Genetics, 4501Leiden University Medical Center, Leiden, the Netherlands
| | - Monique Williams
- Department of Pediatrics, 4501Leiden University Medical Center, Leiden, the Netherlands
| | - Jaap Bakker
- Department of Pediatrics, Erasmus MC-Sophia Children's Hospital, 6984Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Ed Jacobs
- Department of Clinical Chemistry and Laboratory Medicine, 4501Leiden University Medical Center, Leiden, the Netherlands
| | - Lydia Hussaarts-Odijk
- Department of Pediatrics, Erasmus MC-Sophia Children's Hospital, Center of Lysosomal and Metabolic disorders, 6984Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Cacha Peeters
- Department of Neurology, 4501Leiden University Medical Center, Leiden, the Netherlands
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7
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Expanding the genotype-phenotype correlation of childhood sensory polyneuropathy of genetic origin. Sci Rep 2020; 10:16184. [PMID: 32999401 PMCID: PMC7528082 DOI: 10.1038/s41598-020-73219-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/14/2020] [Indexed: 01/02/2023] Open
Abstract
Pure sensory polyneuropathy of genetic origin is rare in childhood and hence important to document the clinical and genetic etiologies from single or multi-center studies. This study focuses on a retrospective chart-review of neurological examinations and genetic and electrodiagnostic data of confirmed sensory polyneuropathy in subjects at a tertiary-care Children's Hospital from 2013 to 2019. Twenty subjects were identified and included. Neurological examination and electrodiagnostic testing showed gait-difficulties, absent tendon reflexes, decreased joint-position, positive Romberg's test and large fiber sensory polyneuropathy on sensory nerve conduction studies in all patients associated with lower-extremity spasticity (6), cardiac abnormalities or cardiomyopathy (5), developmental delay (4), scoliosis (3), epilepsy (3) and hearing-difficulties (2). Confirmation of genetic diagnosis in correlation with clinical presentation was obtained in all cases (COX20 n = 2, HADHA n = 2, POLG n = 1, FXN n = 4, ATXN2 n = 3, ATM n = 3, GAN n = 2, SPG7 n = 1, ZFYVE26 n = 1, FH n = 1). Our single-center study shows genetic sensory polyneuropathies associated with progressive neurodegenerative disorders such as mitochondrial ataxia, Friedreich ataxia, spinocerebellar ataxia type 2, ataxia telangiectasia, spastic paraplegia, giant axonal neuropathy, and fumarate hydratase deficiency. We also present our cohort data in light of clinical features reported for each gene-specific disease subtype in the literature and highlight the importance of genetic testing in the relevant clinical context of electrophysiological findings of peripheral sensory polyneuropathy.
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8
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Sciacovelli M, Schmidt C, Maher ER, Frezza C. Metabolic Drivers in Hereditary Cancer Syndromes. ANNUAL REVIEW OF CANCER BIOLOGY-SERIES 2020. [DOI: 10.1146/annurev-cancerbio-030419-033612] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cancer is a multifaceted disease in which inherited genetic variants can be important drivers of tumorigenesis. The discovery that germline mutations of metabolic genes predispose to familial forms of cancer caused a shift in our understanding of how metabolism contributes to tumorigenesis, providing evidence that metabolic alterations can be oncogenic. In this review, we focus on mitochondrial enzymes whose mutations predispose to familial cancer, and we fully appraise their involvement in cancer formation and progression. Elucidating the molecular mechanisms that orchestrate transformation in these diverse tumors may answer key biological questions about tumor formation and evolution, leading to the identification of new therapeutic targets of intervention.
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Affiliation(s)
- Marco Sciacovelli
- MRC (Medical Research Council) Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, United Kingdom;,
| | - Christina Schmidt
- MRC (Medical Research Council) Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, United Kingdom;,
| | - Eamonn R. Maher
- Department of Medical Genetics, NIHR (National Institute of Health Research) Cambridge Biomedical Research Centre, and Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Christian Frezza
- MRC (Medical Research Council) Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, United Kingdom;,
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9
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Grocott O, Phanor SK, Fung F, Thibert RL, Berkmen MB. Clinical report and biochemical analysis of a patient with fumarate hydratase deficiency. Am J Med Genet A 2019; 182:504-507. [PMID: 31746132 DOI: 10.1002/ajmg.a.61415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/10/2019] [Accepted: 11/02/2019] [Indexed: 11/09/2022]
Abstract
Fumarate hydratase deficiency (FHD) is a rare metabolic disease caused by two defective copies of the FH gene, which encodes the Krebs cycle enzyme fumarase. FHD is associated with brain and developmental abnormalities, seizures, and high childhood mortality. We describe the symptoms and treatment of a patient with FHD. While infantile spasms are common in FHD, the patient presented with epileptic spasms later in childhood. Also unexpectedly, the patient responded excellently to lacosamide for her non-convulsive status epilepticus and epileptic spasms after three first-line medication trials failed. We biochemically analyzed the patient's two fumarase variants (E432Kfs*17 and D65G). While E432Kfs*17 was extremely enzymatically defective, D65G exhibited only a mild defect, possibly playing a role in the patient's longer survival.
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Affiliation(s)
- Olivia Grocott
- Angelman Syndrome Clinic, Massachusetts General Hospital, Boston, Massachusetts
| | - Sabrina K Phanor
- Department of Chemistry and Biochemistry, Suffolk University, Boston, Massachusetts
| | - France Fung
- Angelman Syndrome Clinic, Massachusetts General Hospital, Boston, Massachusetts
| | - Ronald L Thibert
- Angelman Syndrome Clinic, Massachusetts General Hospital, Boston, Massachusetts
| | - Melanie B Berkmen
- Department of Chemistry and Biochemistry, Suffolk University, Boston, Massachusetts
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10
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Ryder B, Moore F, Mitchell A, Thompson S, Christodoulou J, Balasubramaniam S. Fumarase Deficiency: A Safe and Potentially Disease Modifying Effect of High Fat/Low Carbohydrate Diet. JIMD Rep 2017; 40:77-83. [PMID: 29052812 DOI: 10.1007/8904_2017_65] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/24/2017] [Accepted: 10/04/2017] [Indexed: 11/25/2022] Open
Abstract
Fumarate hydratase deficiency (FHD) caused by biallelic alterations of the FH (fumarate hydratase) gene is a rare disorder of the tricarboxylic acid cycle, classically characterized by encephalopathy, profound psychomotor retardation, seizures, a spectrum of brain abnormalities and early death in childhood. Less common milder phenotypes with moderate cognitive impairment and long-term survival have been reported. In addition, heterozygous mutations of the FH gene are responsible for hereditary leiomyomatosis and renal cell cancer (HLRCC). There is currently no recommended disease modifying treatment for FHD and only isolated reports of unsuccessful dietary modifications. Herein, we describe the safe and possibly disease modifying effect of a high fat, low carbohydrate diet in a 14-year-old female with severe FHD.
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Affiliation(s)
- B Ryder
- Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - F Moore
- NSW Biochemical Genetics Service, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - A Mitchell
- Metabolic Dietetic Service, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - S Thompson
- Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
- Metabolic Dietetic Service, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - J Christodoulou
- Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Neurodevelopmental Genomics Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - S Balasubramaniam
- Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia.
- Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
- Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
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11
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Fumarase deficiency: a rare disorder on the crossroads of clinical and metabolic genetics, neurology and cancer. Clin Dysmorphol 2017; 26:117-120. [DOI: 10.1097/mcd.0000000000000148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ait-El-Mkadem S, Dayem-Quere M, Gusic M, Chaussenot A, Bannwarth S, François B, Genin EC, Fragaki K, Volker-Touw CL, Vasnier C, Serre V, van Gassen KL, Lespinasse F, Richter S, Eisenhofer G, Rouzier C, Mochel F, De Saint-Martin A, Abi Warde MT, de Sain-van der Velde MG, Jans JJ, Amiel J, Avsec Z, Mertes C, Haack TB, Strom T, Meitinger T, Bonnen PE, Taylor RW, Gagneur J, van Hasselt PM, Rötig A, Delahodde A, Prokisch H, Fuchs SA, Paquis-Flucklinger V. Mutations in MDH2, Encoding a Krebs Cycle Enzyme, Cause Early-Onset Severe Encephalopathy. Am J Hum Genet 2017; 100:151-159. [PMID: 27989324 PMCID: PMC5223029 DOI: 10.1016/j.ajhg.2016.11.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/16/2016] [Indexed: 01/09/2023] Open
Abstract
MDH2 encodes mitochondrial malate dehydrogenase (MDH), which is essential for the conversion of malate to oxaloacetate as part of the proper functioning of the Krebs cycle. We report bi-allelic pathogenic mutations in MDH2 in three unrelated subjects presenting with early-onset generalized hypotonia, psychomotor delay, refractory epilepsy, and elevated lactate in the blood and cerebrospinal fluid. Functional studies in fibroblasts from affected subjects showed both an apparently complete loss of MDH2 levels and MDH2 enzymatic activity close to null. Metabolomics analyses demonstrated a significant concomitant accumulation of the MDH substrate, malate, and fumarate, its immediate precursor in the Krebs cycle, in affected subjects’ fibroblasts. Lentiviral complementation with wild-type MDH2 cDNA restored MDH2 levels and mitochondrial MDH activity. Additionally, introduction of the three missense mutations from the affected subjects into Saccharomyces cerevisiae provided functional evidence to support their pathogenicity. Disruption of the Krebs cycle is a hallmark of cancer, and MDH2 has been recently identified as a novel pheochromocytoma and paraganglioma susceptibility gene. We show that loss-of-function mutations in MDH2 are also associated with severe neurological clinical presentations in children.
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Vianey-Saban C, Acquaviva C, Cheillan D, Collardeau-Frachon S, Guibaud L, Pagan C, Pettazzoni M, Piraud M, Lamazière A, Froissart R. Antenatal manifestations of inborn errors of metabolism: biological diagnosis. J Inherit Metab Dis 2016; 39:611-624. [PMID: 27393412 DOI: 10.1007/s10545-016-9947-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/03/2016] [Accepted: 05/06/2016] [Indexed: 12/30/2022]
Abstract
Inborn errors of metabolism (IEMs) that present with abnormal imaging findings in the second half of pregnancy are mainly lysosomal storage disorders (LSDs), cholesterol synthesis disorders (CSDs), glycogen storage disorder type IV (GSD IV), peroxisomal disorders, mitochondrial fatty acid oxidation defects (FAODs), organic acidurias, aminoacidopathies, congenital disorders of glycosylation (CDGs), and transaldolase deficiency. Their biological investigation requires fetal material. The supernatant of amniotic fluid (AF) is useful for the analysis of mucopolysaccharides, oligosaccharides, sialic acid, lysosphingolipids and some enzyme activities for LSDs, 7- and 8-dehydrocholesterol, desmosterol and lathosterol for CSDs, acylcarnitines for FAODs, organic acids for organic acidurias, and polyols for transaldolase deficiency. Cultured AF or fetal cells allow the measurement of enzyme activities for most IEMs, whole-cell assays, or metabolite measurements. The cultured cells or tissue samples taken after fetal death can be used for metabolic profiling, enzyme activities, and DNA extraction. Fetal blood can also be helpful. The identification of vacuolated cells orients toward an LSD, and plasma is useful for diagnosing peroxisomal disorders, FAODs, CSDs, some LSDs, and possibly CDGs and aminoacidopathies. We investigated AF of 1700 pregnancies after exclusion of frequent etiologies of nonimmune hydrops fetalis and identified 108 fetuses affected with LSDs (6.3 %), 29 of them with mucopolysaccharidosis type VII (MPS VII), and six with GSD IV (0.3 %). In the AF of 873 pregnancies, investigated because of intrauterine growth restriction and/or abnormal genitalia, we diagnosed 32 fetuses affected with Smith-Lemli-Opitz syndrome (3.7 %).
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Affiliation(s)
- Christine Vianey-Saban
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France.
- Unité INSERM U1060 CarMeN Laboratory, University Lyon-1, Lyon, France.
| | - Cécile Acquaviva
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
- UMR 5305 CNRS/UCBL, Lyon, France
| | - David Cheillan
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
- Unité INSERM U1060 CarMeN Laboratory, University Lyon-1, Lyon, France
| | - Sophie Collardeau-Frachon
- Unité INSERM U1060 CarMeN Laboratory, University Lyon-1, Lyon, France
- Département de Pathologie, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
| | - Laurent Guibaud
- Département d'Imagerie Pédiatrique et Fœtale, Hôpital Femme Mère Enfant CHU de Lyon, Lyon, France
| | - Cécile Pagan
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
- Lyon Neuroscience Research Center, CNRS UMR5292; INSERM U1028, Université Claude Bernard Lyon 1, Lyon, France
| | - Magali Pettazzoni
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
| | - Monique Piraud
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
| | - Antonin Lamazière
- Département PM2, Plateforme de Métabolomique, Peptidomique et dosage de Médicaments, APHP, Hôpital Saint Antoine, Paris, France, Laboratoire de spectrométrie de masse, INSERM ERL 1157, CNRS UMR 7203 LBM, Sorbonne Universités-UPMC, Paris, France
| | - Roseline Froissart
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et de Pathologie Est CHU de Lyon, Lyon, France
- UMR 5305 CNRS/UCBL, Lyon, France
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Chaturvedi S, Singh AK, Keshari AK, Maity S, Sarkar S, Saha S. Human Metabolic Enzymes Deficiency: A Genetic Mutation Based Approach. SCIENTIFICA 2016; 2016:9828672. [PMID: 27051561 PMCID: PMC4804091 DOI: 10.1155/2016/9828672] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 01/21/2016] [Accepted: 01/31/2016] [Indexed: 05/30/2023]
Abstract
One of the extreme challenges in biology is to ameliorate the understanding of the mechanisms which emphasize metabolic enzyme deficiency (MED) and how these pretend to have influence on human health. However, it has been manifested that MED could be either inherited as inborn error of metabolism (IEM) or acquired, which carries a high risk of interrupted biochemical reactions. Enzyme deficiency results in accumulation of toxic compounds that may disrupt normal organ functions and cause failure in producing crucial biological compounds and other intermediates. The MED related disorders cover widespread clinical presentations and can involve almost any organ system. To sum up the causal factors of almost all the MED-associated disorders, we decided to embark on a less traveled but nonetheless relevant direction, by focusing our attention on associated gene family products, regulation of their expression, genetic mutation, and mutation types. In addition, the review also outlines the clinical presentations as well as diagnostic and therapeutic approaches.
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Affiliation(s)
- Swati Chaturvedi
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| | - Ashok K. Singh
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| | - Amit K. Keshari
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| | - Siddhartha Maity
- Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India
| | - Srimanta Sarkar
- Dr. Reddy's Laboratories Limited, Bachupally, Hyderabad, Telangana 502325, India
| | - Sudipta Saha
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
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15
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España A, Ornilla E, Zarate R, Gil-Bazo I, Briones P. Myopathy in hereditary leiomyomatosis and renal cell cancer in an extended family. Br J Dermatol 2015; 172:1442-5. [PMID: 25354562 DOI: 10.1111/bjd.13504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- A España
- Department of Dermatology, University Clinic of Navarra, School of Medicine, University of Navarra, PO Box 4209, Pamplona, 31080, Navarra, Spain.
| | - E Ornilla
- Department of Rheumatology, University Clinic of Navarra, School of Medicine, University of Navarra, PO Box 4209, Pamplona, 31080, Navarra, Spain
| | - R Zarate
- Department of Genetics, University Clinic of Navarra, School of Medicine, University of Navarra, PO Box 4209, Pamplona, 31080, Navarra, Spain
| | - I Gil-Bazo
- Department of Oncology, University Clinic of Navarra, School of Medicine, University of Navarra, PO Box 4209, Pamplona, 31080, Navarra, Spain
| | - P Briones
- IBC-Secció d'Errors Congènits del Metabolisme, Hospital Clínic, Consejo Superior de Investigaciones Científicas (CSIC) y Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
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17
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Haas NB, Nathanson KL. Hereditary kidney cancer syndromes. Adv Chronic Kidney Dis 2014; 21:81-90. [PMID: 24359990 DOI: 10.1053/j.ackd.2013.10.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/17/2013] [Accepted: 10/17/2013] [Indexed: 12/17/2022]
Abstract
Inherited susceptibility to kidney cancer is a fascinating and complex topic. Our knowledge about types of genetic syndromes associated with an increased risk of disease is continually expanding. Currently, there are 10 syndromes associated with an increased risk of all types of kidney cancer, which are reviewed herein. Clear cell kidney cancer is associated with von Hippel Lindau disease, chromosome 3 translocations, PTEN hamartomatous syndrome, and mutations in the BAP1 gene as well as several of the genes encoding the proteins comprising the succinate dehydrogenase complex (SDHB/C/D). Type 1 papillary kidney cancers arise in conjunction with germline mutations in MET and type 2 as part of hereditary leiomyomatosis and kidney cell cancer (fumarate hydratase [FH] mutations). Chromophone and oncocytic kidney cancers are predominantly associated with Birt-Hogg-Dubé syndrome. Patients with Tuberous Sclerosis Complex (TSC) commonly have angiomyolipomas and rarely their malignant counterpart epithelioid angiomyolipomas. The targeted therapeutic options for the kidney cancer associated with these diseases are just starting to expand and are an area of active clinical research.
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Abstract
Fumarase deficiency is a rare autosomal recessive inborn error of metabolism of the Krebs Tricarboxylic Acid cycle. A heavy neurological disease burden is imparted by fumarase deficiency, commonly manifesting as microcephaly, dystonia, global developmental delay, seizures, and lethality in the infantile period. Heterozygous carriers also carry an increased risk of developing hereditary leiomyomatosis and renal cell carcinoma. We describe a non-consanguineous family in whom a dichorionic diamniotic twin pregnancy resulted in twin boys with fumarase deficiency proven at the biochemical, enzymatic, and molecular levels. Their clinical phenotype included hepatic involvement. A novel mutation in the fumarate hydratase gene was identified in this family.
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Mellot-Draznieks C, Valayannopoulos V, Chrétien D, Munnich A, de Lonlay P, Toulhoat H. Relative Enzymatic Activity Levels from In Silico Mutagenesis. ACS Catal 2012. [DOI: 10.1021/cs300538z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Caroline Mellot-Draznieks
- IFP Energies nouvelles, 1&4 Avenue de Bois-Préau, 92852, Rueil-Malmaison Cedex, France
- CNRS, Laboratoire de Chimie
des Processus Biologiques, Collège de France, Paris, France
| | - Vassili Valayannopoulos
- Centre de Référence
des Maladies Héréditaires du Métabolisme, Université de Paris Descartes, Hôpital
des Enfants-Malades, Paris, France
- Unité INSERM U-781, Hôpital des Enfants-Malades, Paris, France
| | | | - Arnold Munnich
- Centre de Référence
des Maladies Héréditaires du Métabolisme, Université de Paris Descartes, Hôpital
des Enfants-Malades, Paris, France
| | - Pascale de Lonlay
- Centre de Référence
des Maladies Héréditaires du Métabolisme, Université de Paris Descartes, Hôpital
des Enfants-Malades, Paris, France
- Unité INSERM U-781, Hôpital des Enfants-Malades, Paris, France
| | - Hervé Toulhoat
- IFP Energies nouvelles, 1&4 Avenue de Bois-Préau, 92852, Rueil-Malmaison Cedex, France
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Brassier A, Ottolenghi C, Boddaert N, Sonigo P, Attié-Bitach T, Millischer-Bellaiche AE, Baujat G, Cormier-Daire V, Valayannopoulos V, Seta N, Piraud M, Chadefaux-Vekemans B, Vianey-Saban C, Froissart R, de Lonlay P. Maladies héréditaires du métabolisme : signes anténatals et diagnostic biologique. Arch Pediatr 2012; 19:959-69. [DOI: 10.1016/j.arcped.2012.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/27/2012] [Indexed: 10/26/2022]
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21
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Spiegel R, Pines O, Ta-Shma A, Burak E, Shaag A, Halvardson J, Edvardson S, Mahajna M, Zenvirt S, Saada A, Shalev S, Feuk L, Elpeleg O. Infantile cerebellar-retinal degeneration associated with a mutation in mitochondrial aconitase, ACO2. Am J Hum Genet 2012; 90:518-23. [PMID: 22405087 DOI: 10.1016/j.ajhg.2012.01.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 12/16/2011] [Accepted: 01/09/2012] [Indexed: 01/11/2023] Open
Abstract
Degeneration of the cerebrum, cerebellum, and retina in infancy is part of the clinical spectrum of lysosomal storage disorders, mitochondrial respiratory chain defects, carbohydrate glycosylation defects, and infantile neuroaxonal dystrophy. We studied eight individuals from two unrelated families who presented at 2-6 months of age with truncal hypotonia and athetosis, seizure disorder, and ophthalmologic abnormalities. Their course was characterized by failure to acquire developmental milestones and culminated in profound psychomotor retardation and progressive visual loss, including optic nerve and retinal atrophy. Despite their debilitating state, the disease was compatible with survival of up to 18 years. Laboratory investigations were normal, but the oxidation of glutamate by muscle mitochondria was slightly reduced. Serial brain MRI displayed progressive, prominent cerebellar atrophy accompanied by thinning of the corpus callosum, dysmyelination, and frontal and temporal cortical atrophy. Homozygosity mapping followed by whole-exome sequencing disclosed a Ser112Arg mutation in ACO2, encoding mitochondrial aconitase, a component of the Krebs cycle. Specific aconitase activity in the individuals' lymphoblasts was severely reduced. Under restrictive conditions, the mutant human ACO2 failed to complement a yeast ACO1 deletion strain, whereas the wild-type human ACO2 succeeded, indicating that this mutation is pathogenic. Thus, a defect in mitochondrial aconitase is associated with an infantile neurodegenerative disorder affecting mainly the cerebellum and retina. In the absence of noninvasive biomarkers, determination of the ACO2 sequence or of aconitase activity in lymphoblasts are warranted in similarly affected individuals, based on clinical and neuroradiologic grounds.
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Raimundo N, Baysal BE, Shadel GS. Revisiting the TCA cycle: signaling to tumor formation. Trends Mol Med 2011; 17:641-9. [PMID: 21764377 DOI: 10.1016/j.molmed.2011.06.001] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 06/03/2011] [Accepted: 06/06/2011] [Indexed: 10/17/2022]
Abstract
A role for mitochondria in tumor formation is suggested by mutations in enzymes of the TCA cycle: isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH) and fumarate hydratase (FH). Although they are all components of the TCA cycle, the resulting clinical presentations do not overlap. Activation of the hypoxia pathway can explain SDH phenotypes, but recent data suggest that FH and IDH mutations lead to tumor formation by repressing cellular differentiation. In this review, we discuss recent findings in the context of both mitochondrial and cytoplasmic components of the TCA cycle, and we propose that extrametabolic roles of TCA cycle metabolites result in reduced cellular differentiation. Furthermore, activation of the pseudohypoxia pathway likely promotes the growth of these neoplasias into tumors.
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Affiliation(s)
- Nuno Raimundo
- Department of Pathology, Yale University School of Medicine, BML 369, 310 Cedar St, New Haven, CT 06520, USA.
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