1
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Bernardino Gomes TM, Vincent AE, Menger KE, Stewart JB, Nicholls TJ. Mechanisms and pathologies of human mitochondrial DNA replication and deletion formation. Biochem J 2024; 481:683-715. [PMID: 38804971 PMCID: PMC11346376 DOI: 10.1042/bcj20230262] [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: 03/22/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Human mitochondria possess a multi-copy circular genome, mitochondrial DNA (mtDNA), that is essential for cellular energy metabolism. The number of copies of mtDNA per cell, and their integrity, are maintained by nuclear-encoded mtDNA replication and repair machineries. Aberrant mtDNA replication and mtDNA breakage are believed to cause deletions within mtDNA. The genomic location and breakpoint sequences of these deletions show similar patterns across various inherited and acquired diseases, and are also observed during normal ageing, suggesting a common mechanism of deletion formation. However, an ongoing debate over the mechanism by which mtDNA replicates has made it difficult to develop clear and testable models for how mtDNA rearrangements arise and propagate at a molecular and cellular level. These deletions may impair energy metabolism if present in a high proportion of the mtDNA copies within the cell, and can be seen in primary mitochondrial diseases, either in sporadic cases or caused by autosomal variants in nuclear-encoded mtDNA maintenance genes. These mitochondrial diseases have diverse genetic causes and multiple modes of inheritance, and show notoriously broad clinical heterogeneity with complex tissue specificities, which further makes establishing genotype-phenotype relationships challenging. In this review, we aim to cover our current understanding of how the human mitochondrial genome is replicated, the mechanisms by which mtDNA replication and repair can lead to mtDNA instability in the form of large-scale rearrangements, how rearranged mtDNAs subsequently accumulate within cells, and the pathological consequences when this occurs.
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Affiliation(s)
- Tiago M. Bernardino Gomes
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- NHS England Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, U.K
| | - Amy E. Vincent
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Katja E. Menger
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - James B. Stewart
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Thomas J. Nicholls
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
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2
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Abduljalil R, Ben Turkia H, Fakhroo A, Skrypnyk C. Fulminant Neonatal Liver Failure in MPV 17-Related Mitochondrial DNA Depletion Syndrome. Case Reports Hepatol 2023; 2023:4514552. [PMID: 37384111 PMCID: PMC10299873 DOI: 10.1155/2023/4514552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 05/03/2023] [Accepted: 05/10/2023] [Indexed: 06/30/2023] Open
Abstract
Mitochondrial depletion syndromes are well established causes of liver failure in infants. Hepatocerebral variant related to MPV17 gene defect is characterized by infantile onset of progressive liver failure, developmental delay, neurological manifestations, lactic acidosis, hypoglycemia, and mtDNA depletion in liver tissue. We report a hepatocerebral variant of mitochondrial DNA depletion syndrome in a neonate who presented with septic shock picture, hypoglycemia, jaundice, hypotonia, and rotatory nystagmus. Family history was significant for consanguinity and a brother who died at the age of 4 months. Investigations showed mild liver function derangement contrasting with severe coagulopathy, hyperlactatemia, and generalized aminoaciduria. The brain MRI was normal. Next generation sequencing (NGS) panel identified a MPV17 gene missense homozygous pathogenic variant. The infant expired at the age of 2 weeks with refractory ascites. This case illustrates a challenging diagnosis causing liver failure and death in neonatal period. Genetic testing of mitochondrial DNA depletion syndromes should be a part of liver failure workup in addition to other treatable disorders presenting with encephalo-hepatopathy in infancy.
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Affiliation(s)
- Razan Abduljalil
- Department of Pediatrics, King Hamad University Hospital, Manama, Bahrain
| | - Hadhami Ben Turkia
- Department of Pediatrics, King Hamad University Hospital, Manama, Bahrain
| | - Aysha Fakhroo
- Department of Pediatrics, King Hamad University Hospital, Manama, Bahrain
| | - Cristina Skrypnyk
- Department of Molecular Medicine, Al‐Jawhara Centre for Molecular Medicine, Arabian Gulf University, Manama, Bahrain
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3
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Uusimaa J, Kettunen J, Varilo T, Järvelä I, Kallijärvi J, Kääriäinen H, Laine M, Lapatto R, Myllynen P, Niinikoski H, Rahikkala E, Suomalainen A, Tikkanen R, Tyynismaa H, Vieira P, Zarybnicky T, Sipilä P, Kuure S, Hinttala R. The Finnish genetic heritage in 2022 – from diagnosis to translational research. Dis Model Mech 2022; 15:278566. [PMID: 36285626 PMCID: PMC9637267 DOI: 10.1242/dmm.049490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Isolated populations have been valuable for the discovery of rare monogenic diseases and their causative genetic variants. Finnish disease heritage (FDH) is an example of a group of hereditary monogenic disorders caused by single major, usually autosomal-recessive, variants enriched in the population due to several past genetic drift events. Interestingly, distinct subpopulations have remained in Finland and have maintained their unique genetic repertoire. Thus, FDH diseases have persisted, facilitating vigorous research on the underlying molecular mechanisms and development of treatment options. This Review summarizes the current status of FDH, including the most recently discovered FDH disorders, and introduces a set of other recently identified diseases that share common features with the traditional FDH diseases. The Review also discusses a new era for population-based studies, which combine various forms of big data to identify novel genotype–phenotype associations behind more complex conditions, as exemplified here by the FinnGen project. In addition to the pathogenic variants with an unequivocal causative role in the disease phenotype, several risk alleles that correlate with certain phenotypic features have been identified among the Finns, further emphasizing the broad value of studying genetically isolated populations.
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Affiliation(s)
- Johanna Uusimaa
- Children and Adolescents, Oulu University Hospital 1 , 90029 Oulu , Finland
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
| | - Johannes Kettunen
- Computational Medicine, Center for Life Course Health Research, University of Oulu 3 , 90014 Oulu , Finland
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare 4 , 00271 Helsinki
- Finland 4 , 00271 Helsinki
- Biocenter Oulu, University of Oulu 5 , 90014 Oulu , Finland
| | - Teppo Varilo
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare 4 , 00271 Helsinki
- Finland 4 , 00271 Helsinki
- Department of Medical Genetics, University of Helsinki 6 , 00251 Helsinki , Finland
| | - Irma Järvelä
- Department of Medical Genetics, University of Helsinki 6 , 00251 Helsinki , Finland
| | - Jukka Kallijärvi
- Folkhälsan Institute of Genetics, Folkhälsan Research Center 7 , 00014 Helsinki , Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
| | - Helena Kääriäinen
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare 4 , 00271 Helsinki
- Finland 4 , 00271 Helsinki
| | - Minna Laine
- Department of Pediatric Neurology, Helsinki University Hospital and University of Helsinki 9 , 00029 Helsinki , Finland
| | - Risto Lapatto
- Children's Hospital, University of Helsinki and Helsinki University Central Hospital 10 , 00029 Helsinki , 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 11 , 90029 Oulu , Finland
| | - Harri Niinikoski
- Research Centre for Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku 12 , 20014 Turku , Finland
- Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku 13 , 20014 Turku , Finland
- Centre for Population Health Research, University of Turku and Turku University Hospital 14 , 20014 Turku , Finland
- Department of Pediatrics, Turku University Hospital 15 , 20014 Turku , Finland
| | - Elisa Rahikkala
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
- Department of Clinical Genetics, Oulu University Hospital 16 , 90029 Oulu , Finland
| | - Anu Suomalainen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- HUS Diagnostics, Helsinki University Hospital 17 , 00014 Helsinki , Finland
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen 18 , D-35392 Giessen , Germany
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki 19 , 00014 Helsinki , Finland
| | - Päivi Vieira
- Children and Adolescents, Oulu University Hospital 1 , 90029 Oulu , Finland
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
| | - Tomas Zarybnicky
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki 20 , 00014 Helsinki , Finland
| | - Petra Sipilä
- Research Centre for Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku 12 , 20014 Turku , Finland
- Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku 21 , 20014 Turku , Finland
| | - Satu Kuure
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- GM-Unit, Laboratory Animal Center, Helsinki Institute of Life Science, University of Helsinki 22 , 00014 Helsinki , Finland
| | - Reetta Hinttala
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
- Biocenter Oulu, University of Oulu 5 , 90014 Oulu , Finland
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4
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Squires JE, Horslen SP. CAQ Corner: Genetic liver disease. Liver Transpl 2022; 28:1231-1244. [PMID: 35377526 DOI: 10.1002/lt.26467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/25/2022] [Accepted: 03/01/2022] [Indexed: 01/13/2023]
Affiliation(s)
- James E Squires
- Division of Gastroenterology, Hepatology and Nutrition, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Simon P Horslen
- Division of Gastroenterology, Hepatology and Nutrition, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
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5
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Peng J, Ramatchandirin B, Pearah A, Maheshwari A, He L. Development and Functions of Mitochondria in Early Life. NEWBORN (CLARKSVILLE, MD.) 2022; 1:131-141. [PMID: 37206110 PMCID: PMC10193534 DOI: 10.5005/jp-journals-11002-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mitochondria are highly dynamic organelles of bacterial origin in eukaryotic cells. These play a central role in metabolism and adenosine triphosphate (ATP) synthesis and in the production and regulation of reactive oxygen species (ROS). In addition to the generation of energy, mitochondria perform numerous other functions to support key developmental events such as fertilization during reproduction, oocyte maturation, and the development of the embryo. During embryonic and neonatal development, mitochondria may have important effects on metabolic, energetic, and epigenetic regulation, which may have significant short- and long-term effects on embryonic and offspring health. Hence, the environment, epigenome, and early-life regulation are all linked by mitochondrial integrity, communication, and metabolism.
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Affiliation(s)
- Jinghua Peng
- Institute of Liver Diseases, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Balamurugan Ramatchandirin
- Department of Pediatrics and Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alexia Pearah
- Department of Pediatrics and Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Akhil Maheshwari
- Global Newborn Society, Clarksville, Maryland, United States of America
| | - Ling He
- Department of Pediatrics and Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Abstract
Neonatal acute liver failure (NALF) is a rare disease with a few known primary causes: gestational alloimmune liver disease (GALD), viral infections, metabolic diseases, and ischemic injury. Many cases still do not have a known cause. Laboratory evaluation may suggest a diagnosis. Most of the known causes have disease-specific treatments that improve outcomes. Survival is improving with better knowledge about and treatment options for GALD; however, overall mortality for NALF is still 24%. Liver transplant remains an important option for neonates with an indeterminate cause of NALF and those who do not respond to established treatments.
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Affiliation(s)
- Catherine Larson-Nath
- Pediatric Gastroenterology, Hepatology & Nutrition, University of Minnesota, 2450 Riverside Avenue, Minneapolis, MN 55454, USA
| | - Bernadette E Vitola
- Pediatric Gastroenterology, Hepatology & Nutrition, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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Wild KT, Goldstein AC, Muraresku C, Ganetzky RD. Broadening the phenotypic spectrum of Pearson syndrome: Five new cases and a review of the literature. Am J Med Genet A 2019; 182:365-373. [PMID: 31825167 DOI: 10.1002/ajmg.a.61433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 11/05/2022]
Abstract
Pearson syndrome (PS) is a multisystem mitochondrial respiratory chain disorder typically characterized by sideroblastic anemia and exocrine pancreatic insufficiency. PS is caused by a single large-scale mitochondrial DNA (mtDNA) deletion. PS classically presents in the first year of life and may be fatal in infancy. Children who survive PS may progress to develop Kearns-Sayre syndrome later in life. The full phenotypic spectrum and prognosis of the condition continue to evolve. Here we report five new patients with PS with unique clinical presentations, including four patients with onset later than previously reported in the literature, and one patient with prenatal onset of symptoms. The timing and unique features of these presentations support an expanded phenotypic spectrum of single large-scale mtDNA deletion syndromes (SLSMDS) and reinforce the importance of including SLSMDS in the differential for children with complex multisystem presentations.
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Affiliation(s)
- K Taylor Wild
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Division of Neonatology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Amy C Goldstein
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Mitochondrial Medicine Frontier Program, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Colleen Muraresku
- Mitochondrial Medicine Frontier Program, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Rebecca D Ganetzky
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Mitochondrial Medicine Frontier Program, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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8
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Tomašić N, Kotarsky H, de Oliveira Figueiredo R, Hansson E, Mörgelin M, Tomašić I, Kallijärvi J, Elmér E, Jauhiainen M, Eklund EA, Fellman V. Fasting reveals largely intact systemic lipid mobilization mechanisms in respiratory chain complex III deficient mice. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165573. [PMID: 31672551 DOI: 10.1016/j.bbadis.2019.165573] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 02/06/2023]
Abstract
Mice homozygous for the human GRACILE syndrome mutation (Bcs1lc.A232G) display decreased respiratory chain complex III activity, liver dysfunction, hypoglycemia, rapid loss of white adipose tissue and early death. To assess the underlying mechanism of the lipodystrophy in homozygous mice (Bcs1lp.S78G), these and wild-type control mice were subjected to a short 4-hour fast. The homozygotes had low baseline blood glucose values, but a similar decrease in response to fasting as in wild-type mice, resulting in hypoglycemia in the majority. Despite the already depleted glycogen and increased triacylglycerol content in the mutant livers, the mice responded to fasting by further depletion and increase, respectively. Increased plasma free fatty acids (FAs) upon fasting suggested normal capacity for mobilization of lipids from white adipose tissue into circulation. Strikingly, however, serum glycerol concentration was not increased concomitantly with free FAs, suggesting its rapid uptake into the liver and utilization for fuel or gluconeogenesis in the mutants. The mutant hepatocyte mitochondria were capable of responding to fasting by appropriate morphological changes, as analyzed by electron microscopy, and by increasing respiration. Mutants showed increased hepatic gene expression of major metabolic controllers typically associated with fasting response (Ppargc1a, Fgf21, Cd36) already in the fed state, suggesting a chronic starvation-like metabolic condition. Despite this, the mutant mice responded largely normally to fasting by increasing hepatic respiration and switching to FA utilization, indicating that the mechanisms driving these adaptations are not compromised by the CIII dysfunction. SUMMARY STATEMENT: Bcs1l mutant mice with severe CIII deficiency, energy deprivation and post-weaning lipolysis respond to fasting similarly to wild-type mice, suggesting largely normal systemic lipid mobilization and utilization mechanisms.
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Affiliation(s)
- Nikica Tomašić
- Lund University, Department of Clinical Sciences, Lund, Pediatrics, Lund, Sweden; Karolinska University Hospital, Department of Neonatology, Stockholm, Sweden; Faculty of Science, Department of Biology, University of Zagreb, Croatia.
| | - Heike Kotarsky
- Department of Pathology, Region Skåne, Lund University, Sweden
| | | | - Eva Hansson
- Lund University, Department of Clinical Sciences, Lund, Pediatrics, Lund, Sweden.
| | - Matthias Mörgelin
- Lund University, Department of Clinical Sciences, Lund, Lund, Sweden.
| | - Ivan Tomašić
- Mälardalen University, Division of Intelligent Future Technologies, Västerås, Sweden.
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Eskil Elmér
- Department of Clinical Sciences, Lund, Mitochondrial Medicine, Lund University, Lund, Sweden.
| | - Matti Jauhiainen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, National Institute for Health and Welfare, Helsinki, Finland.
| | - Erik A Eklund
- Lund University, Department of Clinical Sciences, Lund, Pediatrics, Lund, Sweden.
| | - Vineta Fellman
- Lund University, Department of Clinical Sciences, Lund, Pediatrics, Lund, Sweden; Folkhälsan Research Center, Helsinki, Finland; Children's Hospital, University of Helsinki, Helsinki. Finland.
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9
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Leukocyte mitochondrial DNA copy number as a potential biomarker indicating poor outcome in biliary atresia and its association with oxidative DNA damage and telomere length. Mitochondrion 2019; 47:1-9. [DOI: 10.1016/j.mito.2019.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/11/2019] [Accepted: 04/17/2019] [Indexed: 12/12/2022]
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10
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Cardiovascular Manifestations of Mitochondrial Disease. BIOLOGY 2019; 8:biology8020034. [PMID: 31083569 PMCID: PMC6628328 DOI: 10.3390/biology8020034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/13/2019] [Accepted: 04/22/2019] [Indexed: 02/06/2023]
Abstract
Genetic mitochondrial cardiomyopathies are uncommon causes of heart failure that may not be seen by most physicians. However, the prevalence of mitochondrial DNA mutations and somatic mutations affecting mitochondrial function are more common than previously thought. In this review, the pathogenesis of genetic mitochondrial disorders causing cardiovascular disease is reviewed. Treatment options are presently limited to mostly symptomatic support, but preclinical research is starting to reveal novel approaches that may lead to better and more targeted therapies in the future. With better understanding and clinician education, we hope to improve clinician recognition and diagnosis of these rare disorders in order to improve ongoing care of patients with these diseases and advance research towards discovering new therapeutic strategies to help treat these diseases.
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11
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Moreira-Silva H, Maio I, Bandeira A, Gomes-Martins E, Santos-Silva E. Metabolic liver diseases presenting with neonatal cholestasis: at the crossroad between old and new paradigms. Eur J Pediatr 2019; 178:515-523. [PMID: 30693370 DOI: 10.1007/s00431-019-03328-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/15/2019] [Accepted: 01/17/2019] [Indexed: 12/18/2022]
Abstract
Metabolic liver diseases (MLD) are an important group of disorders presenting with neonatal cholestasis (NC). The spectrum of liver involvement is wide and the presumptive diagnosis is traditionally based on clinical and laboratory findings. Recently, next-generation sequencing (NGS) panels have emerged as an appealing tool to diagnose neonatal/infantile cholestatic disorders. The aim of this study was to identify clinical phenotypes of liver injury and contribute to find a diagnostic methodology that integrates new molecular diagnostic tools. We retrospectively analyzed the clinical and biochemical features of 16 patients with MLD and NC. Patients were categorized into three groups: A-NC with liver failure (N = 8): tyrosinemia type I (n = 2), classic galactosemia (n = 5), mitochondrial DNA depletion syndrome (n = 1); B-NC evolving with chronic liver disease (N = 5): argininemia (n = 2); mitochondrial cytopathy (n = 1); congenital disorders of glycosylation type Ia (n = 1); Zellweger syndrome (n = 1); and C-transient NC (N = 3): Niemann-Pick type C (n = 2), citrullinemia type II (n = 1).Conclusion: MLD presenting with NC can be categorized into three main clinical phenotypes of liver injury. We highlight transient NC as a clue for MLD that must be pursued. New molecular diagnostic tools can play a key role, but application criteria must be established to make them cost-effective. What is Known: • Metabolic liver diseases are an important group of disorders presenting with neonatal cholestasis. • The diagnostic approach is challenging and traditionally based on clinical and laboratory findings. Next-generation sequencing is a recent and rapidly developing tool in pediatric hepatology. What is New: • We provide a liver-targeted characterization of metabolic liver diseases presenting with neonatal cholestasis, categorizing them into three clinical phenotypes that may narrow the diagnostic possibilities. • A clinical decision-making algorithm is proposed, in which the NGS technology is integrated.
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Affiliation(s)
- Helena Moreira-Silva
- Pediatric Gastroenterology Unit, Centro Materno Infantil do Norte - CMIN, Centro Hospitalar Universitário do Porto, Largo da Maternidade de Júlio Dinis, 4050-651, Porto, Portugal
| | - Inês Maio
- Pediatric Gastroenterology Unit, Centro Materno Infantil do Norte - CMIN, Centro Hospitalar Universitário do Porto, Largo da Maternidade de Júlio Dinis, 4050-651, Porto, Portugal
| | - Anabela Bandeira
- Pediatric Metabolic Unit, Centro Materno Infantil do Norte - CMIN, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Esmeralda Gomes-Martins
- Pediatric Metabolic Unit, Centro Materno Infantil do Norte - CMIN, Centro Hospitalar Universitário do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar, Porto, Portugal
| | - Ermelinda Santos-Silva
- Pediatric Gastroenterology Unit, Centro Materno Infantil do Norte - CMIN, Centro Hospitalar Universitário do Porto, Largo da Maternidade de Júlio Dinis, 4050-651, Porto, Portugal. .,Instituto de Ciências Biomédicas Abel Salazar, Porto, Portugal.
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12
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Inbar-Feigenberg M, Blaser S, Hawkins C, Shannon P, Hewson S, Chitayat D. Mitochondrial POLG related disorder presenting prenatally with fetal cerebellar growth arrest. Metab Brain Dis 2018; 33:1369-1373. [PMID: 29574624 DOI: 10.1007/s11011-018-0218-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 03/12/2018] [Indexed: 11/27/2022]
Abstract
We report the prenatal findings of severe cerebellar growth arrest in two siblings with POLG1 mutations. The first presented with seizures and lactic acidosis immediately after premature birth and was diagnosed with mitochondrial disease on muscle biopsy. Molecular DNA analysis confirmed homozygous missense mutation in the POLG1 gene. The pregnancy of the second sibling was monitored closely by repeat fetal ultrasounds since the parents declined invasive testing. A detailed fetal ultrasound at 19 weeks gestation showed a small cerebellum with transcerebellar diameter (TCD) on axial cranial imaging, measuring below the 5th centile for gestational age. Molecular analysis confirmed the same homozygous familial mutation in the POLG1gene. This report further delineates the phenotypic features of the POLG related disorders and expands it to the prenatal era. Subsequent pregnancies were monitored by molecular analysis, using chorionic villus sampling (CVS).
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Affiliation(s)
- Michal Inbar-Feigenberg
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
| | - Susan Blaser
- Department of Diagnostic Imaging, Division of Neuroradiology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Cynthia Hawkins
- Department of Paediatric Laboratory Medicine, Division of Neuropathology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Patrick Shannon
- Department of Pathology & Lab Medicine, Division of Neuropathology, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | - Stacy Hewson
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - David Chitayat
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
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13
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Abstract
INTRODUCTION Pearson syndrome (PS) is a sporadic and very rare syndrome classically associated with single large-scale deletions of mitochondrial DNA and characterized by refractory sideroblastic anemia during infancy. Areas covered: This review presents an analysis and interpretation of the published data that forms the basis for our understanding of PS. PubMed, Google Scholarand Thompson ISI Web of Knowledge were searched for relevant data. Expert commentary: PS is a very rare mitochodrial disease that involves different organs and systems. Clinical phenotype is extremely variable and may change over the course of disease itself with the possibility both of worsenings and improvements. Outcome is invariably lethal and at the moment no cure is available. Accurate supportive treatment and follow up program in centres with experience in mitochondrial diseases and marrow failure may positively influence quality and duration of life.
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Affiliation(s)
- Piero Farruggia
- a Pediatric Hematology and Oncology Unit, Oncology Department , A.R.N.A.S. Ospedali Civico, Di Cristina e Benfratelli , Palermo , Italy
| | - Floriana Di Marco
- a Pediatric Hematology and Oncology Unit, Oncology Department , A.R.N.A.S. Ospedali Civico, Di Cristina e Benfratelli , Palermo , Italy
| | - Carlo Dufour
- b Clinical and Experimental Hematology Unit, G. Gaslini Children's Hospital , Genova , Italy
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14
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Affiliation(s)
- Debra H Pan
- Division of Pediatric Gastroenterology and Nutrition, The Children's Hospital at Montefiore, Bronx, NY
| | - Yolanda Rivas
- Division of Pediatric Gastroenterology and Nutrition, The Children's Hospital at Montefiore, Bronx, NY
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15
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Ünal Ö, Hişmi B, Kılıç M, Gülşen HH, Coşkun T, Sivri SH, Dursun A, Yüce A, Tokatlı A. Deoxyguanosine kinase deficiency: a report of four patients. J Pediatr Endocrinol Metab 2017; 30:697-702. [PMID: 28493820 DOI: 10.1515/jpem-2016-0268] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 04/03/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Hepatic involvement is a common feature in childhood mitochondrial disorders. Deoxyguanosine kinase (DGUOK) deficiency is one of the mitochondrial DNA depletion syndromes associated with hepatocerebral syndrome. Hepatic disease and neurologic dysfunction occurs within weeks after birth. Low birth weight is one of the common features. This study aims to describe the clinical and laboratory features of four infants carrying four different pathogenic variants in the DGUOK gene. CASE PRESENTATION Common clinical findings were progressive cholestatic liver failure, hypoglycemia, hypotonia and rotatory nystagmus in our DGUOK deficiency patients. Lactic acidosis, elevated serum tyrosine and ferritin levels were the striking laboratory features. Cholestasis, iron deposits, microvesicular steatosis and fibrosis were the histopathological findings seen in liver biopsies of two patients. All patients died with multi-organ failure between the ages of 42 days and 6 months. CONCLUSIONS While neurologic findings may occur later in the course of the disease, elevated serum tyrosine levels may alert the physicians to a DGUOK deficiency in a baby with hepatopathy in the presence of the mentioned signs. Early diagnosis is important not only for genetic counseling but also for a possible liver transplantation.
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16
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Purhonen J, Rajendran J, Mörgelin M, Uusi-Rauva K, Katayama S, Krjutskov K, Einarsdottir E, Velagapudi V, Kere J, Jauhiainen M, Fellman V, Kallijärvi J. Ketogenic diet attenuates hepatopathy in mouse model of respiratory chain complex III deficiency caused by a Bcs1l mutation. Sci Rep 2017; 7:957. [PMID: 28424480 PMCID: PMC5430426 DOI: 10.1038/s41598-017-01109-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/23/2017] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial disorders are among the most prevalent inborn errors of metabolism but largely lack treatments and have poor outcomes. High-fat, low-carbohydrate ketogenic diets (KDs) have shown beneficial effects in mouse models of mitochondrial myopathies, with induction of mitochondrial biogenesis as the suggested main mechanism. We fed KD to mice with respiratory chain complex III (CIII) deficiency and progressive hepatopathy due to mutated BCS1L, a CIII assembly factor. The mutant mice became persistently ketotic and tolerated the KD for up to 11 weeks. Liver disease progression was attenuated by KD as shown by delayed fibrosis, reduced cell death, inhibition of hepatic progenitor cell response and stellate cell activation, and normalization of liver enzyme activities. Despite no clear signs of increased mitochondrial biogenesis in the liver, CIII assembly and activity were improved and mitochondrial morphology in hepatocytes normalized. Induction of hepatic glutathione transferase genes and elevated total glutathione level were normalized by KD. Histological findings and transcriptome changes indicated modulation of liver macrophage populations by the mutation and the diet. These results reveal a striking beneficial hepatic response to KD in mice with mitochondrial hepatopathy and warrant further investigations of dietary modification in the management of these conditions in patients.
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Affiliation(s)
- Janne Purhonen
- Folkhälsan Research Center, Helsinki, Finland.,Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jayasimman Rajendran
- Folkhälsan Research Center, Helsinki, Finland.,Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Matthias Mörgelin
- Division of Infection Medicine, Clinical Sciences, Lund University, Lund, Sweden
| | | | - Shintaro Katayama
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Kaarel Krjutskov
- Folkhälsan Research Center, Helsinki, Finland.,Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Competence Centre on Health Technologies, Tartu, Estonia.,Molecular Neurology Research Program, University of Helsinki, Helsinki, Finland
| | - Elisabet Einarsdottir
- Folkhälsan Research Center, Helsinki, Finland.,Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Molecular Neurology Research Program, University of Helsinki, Helsinki, Finland
| | - Vidya Velagapudi
- Metabolomics Unit, Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland
| | - Juha Kere
- Folkhälsan Research Center, Helsinki, Finland.,Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Molecular Neurology Research Program, University of Helsinki, Helsinki, Finland.,Department of Genetics and Molecular Medicine, King's College London, England, UK
| | | | - Vineta Fellman
- Folkhälsan Research Center, Helsinki, Finland.,Department of Clinical Sciences, Lund, Pediatrics, Lund University, Lund, Sweden.,Children's Hospital, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
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17
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Abstract
Liver transplantation originated in children more than 50 years ago, and these youngest patients, while comprising the minority of liver transplant recipients nationwide, can have some of the best and most rewarding outcomes. The indications for liver transplantation in children are generally more diverse than those seen in adult patients. This diversity in underlying cause of disease brings with it increased complexity for all who care for these patients. Children, still being completely dependent on others for survival, also require a care team that is able and ready to work with parents and family in addition to the patient at the center of the process. In this review, we aim to discuss diagnoses of particular uniqueness or importance to pediatric liver transplantation. We also discuss the evaluation of a pediatric patient for liver transplant, the system for allocating them a new liver, and also touch on postoperative concerns that are unique to the pediatric population.
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18
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Rajendran J, Tomašić N, Kotarsky H, Hansson E, Velagapudi V, Kallijärvi J, Fellman V. Effect of High-Carbohydrate Diet on Plasma Metabolome in Mice with Mitochondrial Respiratory Chain Complex III Deficiency. Int J Mol Sci 2016; 17:E1824. [PMID: 27809283 PMCID: PMC5133825 DOI: 10.3390/ijms17111824] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/24/2016] [Accepted: 10/24/2016] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial disorders cause energy failure and metabolic derangements. Metabolome profiling in patients and animal models may identify affected metabolic pathways and reveal new biomarkers of disease progression. Using liver metabolomics we have shown a starvation-like condition in a knock-in (Bcs1lc.232A>G) mouse model of GRACILE syndrome, a neonatal lethal respiratory chain complex III dysfunction with hepatopathy. Here, we hypothesized that a high-carbohydrate diet (HCD, 60% dextrose) will alleviate the hypoglycemia and promote survival of the sick mice. However, when fed HCD the homozygotes had shorter survival (mean ± SD, 29 ± 2.5 days, n = 21) than those on standard diet (33 ± 3.8 days, n = 30), and no improvement in hypoglycemia or liver glycogen depletion. We investigated the plasma metabolome of the HCD- and control diet-fed mice and found that several amino acids and urea cycle intermediates were increased, and arginine, carnitines, succinate, and purine catabolites decreased in the homozygotes. Despite reduced survival the increase in aromatic amino acids, an indicator of liver mitochondrial dysfunction, was normalized on HCD. Quantitative enrichment analysis revealed that glycine, serine and threonine metabolism, phenylalanine and tyrosine metabolism, and urea cycle were also partly normalized on HCD. This dietary intervention revealed an unexpected adverse effect of high-glucose diet in complex III deficiency, and suggests that plasma metabolomics is a valuable tool in evaluation of therapies in mitochondrial disorders.
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Affiliation(s)
- Jayasimman Rajendran
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00014 Helsinki, Finland.
- Institute of Clinical Medicine, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland.
| | - Nikica Tomašić
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, 22185 Lund, Sweden.
- Department of Neonatology, Karolinska University Hospital, 17176 Solna, Sweden.
| | - Heike Kotarsky
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, 22185 Lund, Sweden.
| | - Eva Hansson
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, 22185 Lund, Sweden.
| | - Vidya Velagapudi
- Finnish Institute of Molecular Medicine, University of Helsinki, 00290 Helsinki, Finland.
| | - Jukka Kallijärvi
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00014 Helsinki, Finland.
| | - Vineta Fellman
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00014 Helsinki, Finland.
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, 22185 Lund, Sweden.
- Institute of Clinical medicine, Children's Hospital, Helsinki University Hospital and University of Helsinki, 00029 Helsinki, Finland.
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19
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Stiles AR, Simon MT, Stover A, Eftekharian S, Khanlou N, Wang HL, Magaki S, Lee H, Partynski K, Dorrani N, Chang R, Martinez-Agosto JA, Abdenur JE. Mutations in TFAM, encoding mitochondrial transcription factor A, cause neonatal liver failure associated with mtDNA depletion. Mol Genet Metab 2016; 119:91-9. [PMID: 27448789 DOI: 10.1016/j.ymgme.2016.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/01/2016] [Accepted: 07/02/2016] [Indexed: 10/21/2022]
Abstract
In humans, mitochondrial DNA (mtDNA) depletion syndromes are a group of genetically and clinically heterogeneous autosomal recessive disorders that arise as a consequence of defects in mtDNA replication or nucleotide synthesis. Clinical manifestations are variable and include myopathic, encephalomyopathic, neurogastrointestinal or hepatocerebral phenotypes. Through clinical exome sequencing, we identified a homozygous missense variant (c.533C>T; p.Pro178Leu) in mitochondrial transcription factor A (TFAM) segregating in a consanguineous kindred of Colombian-Basque descent in which two siblings presented with IUGR, elevated transaminases, conjugated hyperbilirubinemia and hypoglycemia with progression to liver failure and death in early infancy. Results of the liver biopsy in the proband revealed cirrhosis, micro- and macrovesicular steatosis, cholestasis and mitochondrial pleomorphism. Electron microscopy of muscle revealed abnormal mitochondrial morphology and distribution while enzyme histochemistry was underwhelming. Electron transport chain testing in muscle showed increased citrate synthase activity suggesting mitochondrial proliferation, while respiratory chain activities were at the lower end of normal. mtDNA content was reduced in liver and muscle (11% and 21% of normal controls respectively). While Tfam mRNA expression was upregulated in primary fibroblasts, Tfam protein level was significantly reduced. Furthermore, functional investigations of the mitochondria revealed reduced basal respiration and spare respiratory capacity, decreased mtDNA copy number and markedly reduced nucleoids. TFAM is essential for transcription, replication and packaging of mtDNA into nucleoids. Tfam knockout mice display embryonic lethality secondary to severe mtDNA depletion. In this report, for the first time, we associate a homozygous variant in TFAM with a novel mtDNA depletion syndrome.
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Affiliation(s)
- Ashlee R Stiles
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA; UCLA Clinical Genomics Center, Los Angeles, CA 90095, USA
| | - Mariella T Simon
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA; Department of Developmental and Cellular Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Alexander Stover
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Shaya Eftekharian
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Negar Khanlou
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Hanlin L Wang
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Shino Magaki
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Hane Lee
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA; UCLA Clinical Genomics Center, Los Angeles, CA 90095, USA
| | - Kate Partynski
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Nagmeh Dorrani
- Department of Pediatrics, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Richard Chang
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Julian A Martinez-Agosto
- UCLA Clinical Genomics Center, Los Angeles, CA 90095, USA; Department of Pediatrics, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Jose E Abdenur
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA; Department of Pediatrics, University of California Irvine, Orange, CA 92868, USA.
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20
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Deep Sequencing Reveals Novel Genetic Variants in Children with Acute Liver Failure and Tissue Evidence of Impaired Energy Metabolism. PLoS One 2016; 11:e0156738. [PMID: 27483465 PMCID: PMC4970743 DOI: 10.1371/journal.pone.0156738] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 05/10/2016] [Indexed: 01/21/2023] Open
Abstract
Background & Aims The etiology of acute liver failure (ALF) remains elusive in almost half of affected children. We hypothesized that inherited mitochondrial and fatty acid oxidation disorders were occult etiological factors in patients with idiopathic ALF and impaired energy metabolism. Methods Twelve patients with elevated blood molar lactate/pyruvate ratio and indeterminate etiology were selected from a retrospective cohort of 74 subjects with ALF because their fixed and frozen liver samples were available for histological, ultrastructural, molecular and biochemical analysis. Results A customized next-generation sequencing panel for 26 genes associated with mitochondrial and fatty acid oxidation defects revealed mutations and sequence variants in five subjects. Variants involved the genes ACAD9, POLG, POLG2, DGUOK, and RRM2B; the latter not previously reported in subjects with ALF. The explanted livers of the patients with heterozygous, truncating insertion mutations in RRM2B showed patchy micro- and macrovesicular steatosis, decreased mitochondrial DNA (mtDNA) content <30% of controls, and reduced respiratory chain complex activity; both patients had good post-transplant outcome. One infant with severe lactic acidosis was found to carry two heterozygous variants in ACAD9, which was associated with isolated complex I deficiency and diffuse hypergranular hepatocytes. The two subjects with heterozygous variants of unknown clinical significance in POLG and DGUOK developed ALF following drug exposure. Their hepatocytes displayed abnormal mitochondria by electron microscopy. Conclusion Targeted next generation sequencing and correlation with histological, ultrastructural and functional studies on liver tissue in children with elevated lactate/pyruvate ratio expand the spectrum of genes associated with pediatric ALF.
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21
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Saneto RP. Alpers-Huttenlocher syndrome: the role of a multidisciplinary health care team. J Multidiscip Healthc 2016; 9:323-33. [PMID: 27555780 PMCID: PMC4968991 DOI: 10.2147/jmdh.s84900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Alpers–Huttenlocher syndrome (AHS) is a mitochondrial DNA-depletion syndrome. Age of onset is bimodal: early onset at 2–4 years and later adolescent onset at 17–24 years of age. Early development is usually normal, with epilepsy heralding the disorder in ~50% of patients. The onset of seizures is coupled with progressive cognitive decline. Hepatopathy is variable, and when present is a progressive dysfunction leading to liver failure in many cases. These features of seizures, cognitive degeneration, and hepatopathy represent the “classic triad” of AHS. However, most patients develop other system involvement. Therefore, although AHS is ultimately a lethal disorder, medical care is required for sustained quality of life. Frequently, additional organ systems – gastrointestinal, respiratory, nutritional, and psychiatric – abnormalities appear and need treatment. Rarely, cardiovascular dysfunction and even pregnancy complicate medical treatment. Optimal care requires a team of physicians and caretakers to make sure quality of life is optimized. The care team, together with the family and palliative care specialists, need to be in communication as the disease progresses and medical changes occur. Although the unpredictable losses of function challenge medical care, the team approach can foster the individual quality-of-life care needed for the patient and family.
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Affiliation(s)
- Russell P Saneto
- Department of Neurology, University of Washington; Division of Pediatric Neurology, Seattle Children's Hospital, Seattle, WA, USA
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22
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Lane M, Boczonadi V, Bachtari S, Gomez-Duran A, Langer T, Griffiths A, Kleinle S, Dineiger C, Abicht A, Holinski-Feder E, Schara U, Gerner P, Horvath R. Mitochondrial dysfunction in liver failure requiring transplantation. J Inherit Metab Dis 2016; 39:427-436. [PMID: 27053192 PMCID: PMC4851707 DOI: 10.1007/s10545-016-9927-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/10/2016] [Accepted: 03/10/2016] [Indexed: 01/14/2023]
Abstract
Liver failure is a heterogeneous condition which may be fatal and the primary cause is frequently unknown. We investigated mitochondrial oxidative phosphorylation in patients undergoing liver transplantation. We studied 45 patients who had liver transplantation due to a variety of clinical presentations. Blue native polyacrylamide gel electrophoresis with immunodetection of respiratory chain complexes I-V, biochemical activity of respiratory chain complexes II and IV and quantification of mitochondrial DNA (mtDNA) copy number were investigated in liver tissue collected from the explanted liver during transplantation. Abnormal mitochondrial function was frequently present in this cohort: ten of 40 patients (25 %) had a defect of one or more respiratory chain enzyme complexes on blue native gels, 20 patients (44 %) had low activity of complex II and/or IV and ten (22 %) had a reduced mtDNA copy number. Combined respiratory chain deficiency and reduced numbers of mitochondria were detected in all three patients with acute liver failure. Low complex IV activity in biliary atresia and complex II defects in cirrhosis were common findings. All six patients diagnosed with liver tumours showed variable alterations in mitochondrial function, probably due to the heterogeneity of the presenting tumour. In conclusion, mitochondrial dysfunction is common in severe liver failure in non-mitochondrial conditions. Therefore, in contrast to the common practice detection of respiratory chain abnormalities in liver should not restrict the inclusion of patients for liver transplantation. Furthermore, improving mitochondrial function may be targeted as part of a complex therapy approach in different forms of liver diseases.
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Affiliation(s)
- Maria Lane
- Institute of Genetic Medicine, John Walton Muscular Dystrophy Research Centre and Wellcome Trust Centre for Mitochondrial Research, Central Parkway, NE1 3BZ, Newcastle upon Tyne, UK
| | - Veronika Boczonadi
- Institute of Genetic Medicine, John Walton Muscular Dystrophy Research Centre and Wellcome Trust Centre for Mitochondrial Research, Central Parkway, NE1 3BZ, Newcastle upon Tyne, UK
| | - Sahar Bachtari
- Department of Paediatric Gastroenterology, University of Duisburg-Essen, Essen, Germany
| | - Aurora Gomez-Duran
- Institute of Genetic Medicine, John Walton Muscular Dystrophy Research Centre and Wellcome Trust Centre for Mitochondrial Research, Central Parkway, NE1 3BZ, Newcastle upon Tyne, UK
| | - Thorsten Langer
- Department for Neuropediatrics and Muscular Diseases, Center for Pediatrics and Adolescent Medicine University Medical Center Freiburg, Freiburg, Germany
| | - Alexandra Griffiths
- Institute of Genetic Medicine, John Walton Muscular Dystrophy Research Centre and Wellcome Trust Centre for Mitochondrial Research, Central Parkway, NE1 3BZ, Newcastle upon Tyne, UK
| | | | | | | | | | - Ulrike Schara
- Department of Paediatric Neurology, University of Duisburg-Essen, Essen, Germany
| | - Patrick Gerner
- Department of Paediatric Gastroenterology, University of Duisburg-Essen, Essen, Germany
- Paediatric Gastroenterology/Hepatology, University of Freiburg, Freiburg, Germany
| | - Rita Horvath
- Institute of Genetic Medicine, John Walton Muscular Dystrophy Research Centre and Wellcome Trust Centre for Mitochondrial Research, Central Parkway, NE1 3BZ, Newcastle upon Tyne, UK.
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23
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Crippa BL, Leon E, Calhoun A, Lowichik A, Pasquali M, Longo N. Biochemical abnormalities in Pearson syndrome. Am J Med Genet A 2016; 167A:621-8. [PMID: 25691415 DOI: 10.1002/ajmg.a.36939] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/15/2014] [Indexed: 01/10/2023]
Abstract
Pearson marrow-pancreas syndrome is a multisystem mitochondrial disorder characterized by bone marrow failure and pancreatic insufficiency. Children who survive the severe bone marrow dysfunction in childhood develop Kearns-Sayre syndrome later in life. Here we report on four new cases with this condition and define their biochemical abnormalities. Three out of four patients presented with failure to thrive, with most of them having normal development and head size. All patients had evidence of bone marrow involvement that spontaneously improved in three out of four patients. Unique findings in our patients were acute pancreatitis (one out of four), renal Fanconi syndrome (present in all patients, but symptomatic only in one), and an unusual organic aciduria with 3-hydroxyisobutyric aciduria in one patient. Biochemical analysis indicated low levels of plasma citrulline and arginine, despite low-normal ammonia levels. Regression analysis indicated a significant correlation between each intermediate of the urea cycle and the next, except between ornithine and citrulline. This suggested that the reaction catalyzed by ornithine transcarbamylase (that converts ornithine to citrulline) might not be very efficient in patients with Pearson syndrome. In view of low-normal ammonia levels, we hypothesize that ammonia and carbamylphosphate could be diverted from the urea cycle to the synthesis of nucleotides in patients with Pearson syndrome and possibly other mitochondrial disorders.
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Affiliation(s)
- Beatrice Letizia Crippa
- Department of Pediatrics, Division of Medical Genetics, University of Utah, Salt Lake City, Utah; University of Milano, Milan, Italy
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24
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Leslie N, Wang X, Peng Y, Valencia CA, Khuchua Z, Hata J, Witte D, Huang T, Bove KE. Neonatal multiorgan failure due to ACAD9 mutation and complex I deficiency with mitochondrial hyperplasia in liver, cardiac myocytes, skeletal muscle, and renal tubules. Hum Pathol 2016; 49:27-32. [DOI: 10.1016/j.humpath.2015.09.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/21/2015] [Accepted: 09/25/2015] [Indexed: 11/16/2022]
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25
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Roumiantsev S, Shah U, Westra SJ, Misdraji J. CASE RECORDS of the MASSACHUSETTS GENERAL HOSPITAL. Case 20-2015. A Newborn Girl with Hypotension, Coagulopathy, Anemia, and Hyperbilirubinemia. N Engl J Med 2015; 372:2542-53. [PMID: 26107055 DOI: 10.1056/nejmcpc1404334] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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26
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Hepatic Copper Accumulation: A Novel Feature in Transient Infantile Liver Failure Due to TRMU Mutations? JIMD Rep 2015; 21:109-13. [PMID: 25665837 DOI: 10.1007/8904_2014_402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 12/18/2014] [Accepted: 12/19/2014] [Indexed: 12/13/2022] Open
Abstract
Defects in the mitochondrial respiratory chain can induce a heterogeneous range of clinical and biochemical manifestations. Hepatic involvement includes acute fulminant hepatic failure, microvesicular steatosis, neonatal non-alloimmune haemochromatosis and cirrhosis. Recently pathogenic mutations in tRNA 5-methylaminomethyl-2-thiouridylate methyltransferase (TRMU) gene (OMIM 610230) have been demonstrated to cause transient infantile liver failure (OMIM 613070). The human TRMU gene encodes a mitochondrial protein, 5-methylaminomethyl-2-thiouridylate methyltransferase, whose molecular function is that of mitochondrial tRNA modification.We report an infant who presented with acute liver failure, in whom we observed hepatic copper intoxication and cirrhosis on liver biopsy. We postulate that the hepatic copper intoxication observed in our patient is most likely a secondary event associated with cholangiopathy. Periportal copper accumulation has been implicated in causing secondary mitochondrial dysfunction; the impact of copper accumulation in patients with TRMU mutations is unclear and warrants long-term clinical follow-up.
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27
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Götze T, Blessing H, Grillhösl C, Gerner P, Hoerning A. Neonatal Cholestasis - Differential Diagnoses, Current Diagnostic Procedures, and Treatment. Front Pediatr 2015; 3:43. [PMID: 26137452 PMCID: PMC4470262 DOI: 10.3389/fped.2015.00043] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 04/29/2015] [Indexed: 12/18/2022] Open
Abstract
Cholestatic jaundice in early infancy is a complex diagnostic problem. Misdiagnosis of cholestasis as physiologic jaundice delays the identification of severe liver diseases. In the majority of infants, prolonged physiologic jaundice represent benign cases of breast milk jaundice, but few among them are masked and caused by neonatal cholestasis (NC) that requires a prompt diagnosis and treatment. Therefore, a prolonged neonatal jaundice, longer than 2 weeks after birth, must always be investigated because an early diagnosis is essential for appropriate management. To rapidly identify the cases with cholestatic jaundice, the conjugated bilirubin needs to be determined in any infant presenting with prolonged jaundice at 14 days of age with or without depigmented stool. Once NC is confirmed, a systematic approach is the key to reliably achieve the diagnosis in order to promptly initiate the specific, and in many cases, life-saving therapy. This strategy is most important to promptly identify and treat infants with biliary atresia, the most common cause of NC, as this requires a hepatoportoenterostomy as soon as possible. Here, we provide a detailed work-up approach including initial treatment recommendations and a clinically oriented overview of possible differential diagnoses in order to facilitate the early recognition and a timely diagnosis of cholestasis. This approach warrants a broad spectrum of diagnostic procedures and investigations including new methods that are described in this review.
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Affiliation(s)
- Thomas Götze
- Department for Pediatric and Adolescent Medicine, Friedrich-Alexander University of Erlangen-Nuremberg , Erlangen , Germany
| | - Holger Blessing
- Department for Pediatric and Adolescent Medicine, Friedrich-Alexander University of Erlangen-Nuremberg , Erlangen , Germany
| | - Christian Grillhösl
- Department for Pediatric and Adolescent Medicine, Friedrich-Alexander University of Erlangen-Nuremberg , Erlangen , Germany
| | - Patrick Gerner
- Department for Pediatric and Adolescent Medicine, Albert-Ludwigs-University Freiburg , Freiburg , Germany
| | - André Hoerning
- Department for Pediatric and Adolescent Medicine, Friedrich-Alexander University of Erlangen-Nuremberg , Erlangen , Germany
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28
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Heissat S, Collardeau-Frachon S, Baruteau J, Dubruc E, Bouvier R, Fabre M, Cordier MP, Broué P, Guigonis V, Debray D. Neonatal hemochromatosis: diagnostic work-up based on a series of 56 cases of fetal death and neonatal liver failure. J Pediatr 2015; 166:66-73. [PMID: 25444000 DOI: 10.1016/j.jpeds.2014.09.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 08/14/2014] [Accepted: 09/18/2014] [Indexed: 01/02/2023]
Abstract
OBJECTIVE To define an algorithm to improve diagnosis of neonatal hemochromatosis (NH) related to gestational alloimmune liver disease (GALD), which is diagnosed by immunohistochemistry demonstrating activated complement at hepatocytes (IDACH). STUDY DESIGN We assessed 56 instances of fetal death or neonatal liver failure (NLF; 2006-2009), 29 (7 stillborns, 22 NLF) with NH, and 27 (5 stillborns, 22 NLF) without NH (non-NH). Immunohistochemistry was retrospectively performed in 21 cases. Cases were grouped as follows: (1) GALD as demonstrated by IDACH (n = 17); (2) indeterminate for GALD (n = 28); or (3) alternate diagnosis found (n = 11). We compared cases of immunohistochemically proven GALD with those with an alternate diagnosis. RESULTS Of the 12 stillborns, 7 had NH because of GALD (NH-GALD), one was undeterminate, and 4 had alternate diagnoses (GALD excluded). Of the 22 newborns with NH, 6 had NH-GALD, one had mitochondrial respiratory chain disorder (MRCD), and 15 were indeterminate for GALD. Of 22 non-NH newborns, extrahepatic siderosis (EHS) was not assessed in 13 (3 GALD, 1 alternate diagnosis [MRCD] and 9 indeterminate GALD) and excluded in 9 (5 alternate diagnoses and 4 indeterminate GALD). The only clinical features found to be associated with GALD were intrafamilial recurrence, prematurity, and EHS. CONCLUSIONS In unexplained fetal death or NLF, the diagnosis of subsets of NH requires tissue analysis (autopsy) to assess EHS. In patients with NH, if MRCD is ruled out, NH-GALD is likely. The rate of IDACH in the diagnosis of GALD in cases without NH requires further study.
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Affiliation(s)
- Sophie Heissat
- Department of Pediatric Gastroenterology and Hepatology, Hôpital Femme Mère Enfant, Hospices Civils de Lyon et Université Lyon 1, Lyon, France.
| | - Sophie Collardeau-Frachon
- Department of Pathology, Hôpital Femme Mère Enfant, Hospices Civils de Lyon et Université Lyon 1, Lyon, France
| | - Julien Baruteau
- Department of Pediatric Hepatology and Metabolic Diseases, CHU Toulouse, Toulouse, France
| | - Estelle Dubruc
- Department of Pathology, Hôpital Femme Mère Enfant, Hospices Civils de Lyon et Université Lyon 1, Lyon, France
| | - Raymonde Bouvier
- Department of Pathology, Hôpital Femme Mère Enfant, Hospices Civils de Lyon et Université Lyon 1, Lyon, France
| | | | | | - Pierre Broué
- Department of Pediatric Hepatology and Metabolic Diseases, CHU Toulouse, Toulouse, France
| | - Vincent Guigonis
- Department of Pediatrics, Hôpital Mère et Enfant, CHU Limoges, Limoges, France
| | - Dominique Debray
- Medical-Surgical Center, Hepatology, and Transplantation AP-HP, Hôpital Necker Enfants Malades, Paris, France
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Shen Z, Liu C, Liu P, Zhao J, Xu W. Sphingosine 1-phosphate (S1P) promotes mitochondrial biogenesis in Hep G2 cells by activating Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α). Cell Stress Chaperones 2014; 19:541-8. [PMID: 24293320 PMCID: PMC4041936 DOI: 10.1007/s12192-013-0480-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 11/18/2013] [Accepted: 11/19/2013] [Indexed: 12/24/2022] Open
Abstract
Sphingosine 1-phosphate (S1P), a potent bioactive phospholipid, has been reported to regulate a broad spectrum of biological processes. However, little is known regarding S1P's effects on mitochondrial function. In this study, we investigated the S1P's effects on the Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) signaling pathway and mitochondrial biogenesis in Hep G2 cells. Our results indicate that administration of S1P leads to a significant upregulation of mitochondrial DNA replication and transcription, increased mitochondrial mass, and elevated adenosine triphosphate synthesis. In addition, we found that treatment with S1P stimulates expression of PGC-1α, a master regulator of mitochondrial biogenesis, as well as its downstream targets: nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM). Moreover, our data demonstrate that S1P's effects on PGC-1α and mitochondrial biogenesis are mediated by the protein kinase A/cAMP response element-binding protein (PKA/CREB) pathway. Importantly, we also revealed that S1P's effects on mitochondrial biogenesis are dependent on its type 2 receptor (S1P2), though not on either its type 1 (S1P1) or type 3 (S1P3) receptors. Based on these observations, we concluded that S1P activates the PKA/CREB pathway through S1P2, which then promotes expression of PGC-1α/NRF1/TFAM and subsequent mitochondrial biogenesis in Hep G2 cells.
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Affiliation(s)
- Zhixin Shen
- />Clinical Hospital of Weifang Medical University, Weifang, China
| | - Chong Liu
- />The Affiliated Hospital of Weifang Medical University, No. 465 Yuhe Road, Kuiwen District, Weifang City, 261031 Shandong People’s Republic of China
| | - Pingping Liu
- />The Affiliated Hospital of Weifang Medical University, No. 465 Yuhe Road, Kuiwen District, Weifang City, 261031 Shandong People’s Republic of China
| | - Jiamin Zhao
- />The 89th Hospital of Chinese People’s Liberation Army, Weifang, China
| | - Wanpeng Xu
- />The Affiliated Hospital of Weifang Medical University, No. 465 Yuhe Road, Kuiwen District, Weifang City, 261031 Shandong People’s Republic of China
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Kasapkara ÇS, Tümer L, Ezgü FS, Küçükçongar A, Hasanoğlu A. BCS1L gene mutation causing GRACILE syndrome: case report. Ren Fail 2014; 36:953-4. [DOI: 10.3109/0886022x.2014.900422] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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31
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Davoudi M, Kallijärvi J, Marjavaara S, Kotarsky H, Hansson E, Levéen P, Fellman V. A mouse model of mitochondrial complex III dysfunction induced by myxothiazol. Biochem Biophys Res Commun 2014; 446:1079-84. [PMID: 24661880 DOI: 10.1016/j.bbrc.2014.03.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 03/15/2014] [Indexed: 11/17/2022]
Abstract
Myxothiazol is a respiratory chain complex III (CIII) inhibitor that binds to the ubiquinol oxidation site Qo of CIII. It blocks electron transfer from ubiquinol to cytochrome b and thus inhibits CIII activity. It has been utilized as a tool in studies of respiratory chain function in in vitro and cell culture models. We developed a mouse model of biochemically induced and reversible CIII inhibition using myxothiazol. We administered myxothiazol intraperitoneally at a dose of 0.56 mg/kg to C57Bl/J6 mice every 24 h and assessed CIII activity, histology, lipid content, supercomplex formation, and gene expression in the livers of the mice. A reversible CIII activity decrease to 50% of control value occurred at 2 h post-injection. At 74 h only minor histological changes in the liver were found, supercomplex formation was preserved and no significant changes in the expression of genes indicating hepatotoxicity or inflammation were found. Thus, myxothiazol-induced CIII inhibition can be induced in mice for four days in a row without overt hepatotoxicity or lethality. This model could be utilized in further studies of respiratory chain function and pharmacological approaches to mitochondrial hepatopathies.
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Affiliation(s)
- Mina Davoudi
- Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185, Sweden
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014, Finland
| | - Sanna Marjavaara
- Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014, Finland
| | - Heike Kotarsky
- Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185, Sweden
| | - Eva Hansson
- Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185, Sweden
| | - Per Levéen
- Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185, Sweden; Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014, Finland
| | - Vineta Fellman
- Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185, Sweden; Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014, Finland; Children's Hospital, Helsinki University Hospital, University of Helsinki, Helsinki 00029, Finland.
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Abstract
Molecular pathogenesis may be elucidated for inherited bone marrow failure syndromes (IBMFS). The study and presentation of the details of their molecular biology and biochemistry is warranted for appropriate diagnosis and management of afflicted patients and to identify the physiology of the normal hematopoiesis and mechanisms of carcinogenesis. Several themes have emerged within each subsection of IBMFS, including the ribosomopathies, which include ribosome assembly and ribosomal RNA processing. The Fanconi anemia pathway has become interdigitated with the familial breast cancer syndromes. In this article, the diseases that account for most IBMFS diagnoses are analyzed.
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Affiliation(s)
- S Deborah Chirnomas
- Section of Pediatric Hematology-Oncology, LMP 2073, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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Abstract
To highlight differences between early-onset and adult mitochondrial depletion syndromes (MDS) concerning etiology and genetic background, pathogenesis, phenotype, clinical presentation and their outcome. MDSs most frequently occur in neonates, infants, or juveniles and more rarely in adolescents or adults. Mutated genes phenotypically presenting with adult-onset MDS include POLG1, TK2, TyMP, RRM2B, or PEO1/twinkle. Adult MDS manifest similarly to early-onset MDS, as myopathy, encephalo-myopathy, hepato-cerebral syndrome, or with chronic progressive external ophthalmoplegia (CPEO), fatigue, or only minimal muscular manifestations. Diagnostic work-up or treatment is not at variance from early-onset cases. Histological examination of muscle may be normal but biochemical investigations may reveal multiple respiratory chain defects. The outcome appears to be more favorable in adult than in early-onset forms. Mitochondrial depletion syndromes is not only a condition of neonates, infants, or juveniles but rarely also occurs in adults, presenting with minimal manifestations or manifestations like in the early-onset forms. Outcome of adult-onset MDS appears more favorable than early-onset MDS.
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Hazard FK, Ficicioglu CH, Ganesh J, Ruchelli ED. Liver pathology in infantile mitochondrial DNA depletion syndrome. Pediatr Dev Pathol 2013; 16:415-24. [PMID: 24050659 DOI: 10.2350/12-07-1229-oa.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitochondrial DNA (mtDNA) depletion syndrome is a relatively novel cause of hepatic dysfunction in the pediatric population. It is caused by mutations in either mtDNA or nuclear DNA (nDNA) that result in a quantitative reduction in mtDNA and, in turn, dysfunctional oxidative phosphorylation. In infants, it results in the hepatocerebral phenotype, characterized by hyperbilirubinemia, coagulopathy, lactic acidosis, hypoglycemia, lethargy, encephalopathy, developmental delay, and hypotonia. Three infants diagnosed with mtDNA depletion syndrome at The Children's Hospital of Philadelphia were identified, and their clinical presentation, disease course, and histologic and ultrastructural features of liver samples (pre- and postmortem) were characterized. While a different mutant gene was identified in each child, they all showed clinical evidence of metabolic dysfunction soon after birth and expired by 1 year of age. Steatosis, cholestasis, and cytoplasmic crowding by atypical mitochondria were consistent pathologic liver findings. Other findings included hepatocyte hypereosinophilia, fibrosis, and hemosiderosis. This analysis provides insight into the important clinical signs/symptoms and histopathologic and ultrastructural features of mtDNA depletion syndrome in infants and young children. Knowledge of these characteristics will facilitate early recognition and appropriate treatment of this rare disorder. Additionally, ultrastructural evaluation of liver samples by electron microscopy is an important diagnostic component of hepatic dysfunction caused by metabolic abnormalities. This type of analysis should be routinely employed in the setting of unexplained cholestasis, especially when accompanied by steatosis and hepatocyte hypereosinophilia.
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Affiliation(s)
- Florette K Hazard
- 1 Departments of Pathology and Pediatrics, Stanford University School of Medicine, Stanford, CA 94305 USA
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35
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DGUOK-related mitochondrial DNA depletion syndrome in a child with an early diagnosis of glycogen storage disease. J Pediatr Gastroenterol Nutr 2013; 57:e28-9. [PMID: 22868686 DOI: 10.1097/mpg.0b013e31826bd4ed] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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36
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Lee WS, Sokol RJ. Mitochondrial hepatopathies: advances in genetics, therapeutic approaches, and outcomes. J Pediatr 2013; 163:942-8. [PMID: 23810725 PMCID: PMC3934633 DOI: 10.1016/j.jpeds.2013.05.036] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/24/2013] [Accepted: 05/14/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Way Seah Lee
- Department of Pediatrics, University of Malaya Medical Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO
- Pediatrics and Child Health Research Group, University of Malaya, Kuala Lumpur, Malaysia, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO
| | - Ronald J. Sokol
- Section of Pediatric Gastroenterology, Hepatology, and Nutrition and the Digestive Health Institute, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO
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37
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Enkai S, Koinuma S, Ito R, Igaki J, Hasegawa Y, Murayama K, Ohtake A. Case of an infant with hepatic cirrhosis caused by mitochondrial respiratory chain disorder. Pediatr Int 2013; 55:e103-6. [PMID: 23910810 DOI: 10.1111/ped.12098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 01/17/2013] [Accepted: 02/19/2013] [Indexed: 11/27/2022]
Abstract
The patient had hepatomegaly with liver dysfunction at the age of 1 month. Magnetic resonance imaging performed at the age of 1 year showed multiple nodules of varying size in his liver. We were able to examine the mitochondrial respiratory chain function in the liver biopsy samples because all other differential diagnoses for hepatic cirrhosis had been ruled out. Complex I and IV activities were below the normal level (<30%) of the citrate synthase (CS) ratio. Liver blue native polyacrylamide gel electrophoresis showed an extremely weak complex I and IV band. Liver respiratory chain complexes I and IV were found to be deficient in this patient. The histologic findings were highly suggestive of mitochondrial respiratory chain disorder. Findings of progressive liver cirrhosis changes were observed in magnetic resonance imaging at the age of 5 years. An examination of the mitochondrial respiratory chain function should be performed along with a liver biopsy if mitochondrial respiratory chain disorder is suspected as a possible differential diagnosis of idiopathic hepatitis.
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Abstract
Alpers-Huttenlocher syndrome is an uncommon mitochondrial disease most often associated with mutations in the mitochondrial DNA replicase, polymerase-γ. Alterations in enzyme activity result in reduced levels or deletions in mitochondrial DNA. Phenotypic manifestations occur when the functional content of mitochondrial DNA reaches a critical nadir. The tempo of disease progression and onset varies among patients, even in identical genotypes. The classic clinical triad of seizures, liver degeneration, and progressive developmental regression helps define the disorder, but a wide range of clinical expression occurs. The majority of patients are healthy before disease onset, and seizures herald the disorder in most patients. Seizures can rapidly progress to medical intractability, with frequent episodes of epilepsia partialis continua or status epilepticus. Liver involvement may precede or occur after seizure onset. Regardless, eventual liver failure is common. Both the tempo of disease progression and range of organ involvement vary from patient to patient, and are only partly explained by pathogenic effects of genetic mutations. Diagnosis involves the constellation of organ involvement, not the sequence of signs. This disorder is relentlessly progressive and ultimately fatal.
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39
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Cotter DG, Schugar RC, Crawford PA. Ketone body metabolism and cardiovascular disease. Am J Physiol Heart Circ Physiol 2013; 304:H1060-76. [PMID: 23396451 DOI: 10.1152/ajpheart.00646.2012] [Citation(s) in RCA: 294] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ketone bodies are metabolized through evolutionarily conserved pathways that support bioenergetic homeostasis, particularly in brain, heart, and skeletal muscle when carbohydrates are in short supply. The metabolism of ketone bodies interfaces with the tricarboxylic acid cycle, β-oxidation of fatty acids, de novo lipogenesis, sterol biosynthesis, glucose metabolism, the mitochondrial electron transport chain, hormonal signaling, intracellular signal transduction pathways, and the microbiome. Here we review the mechanisms through which ketone bodies are metabolized and how their signals are transmitted. We focus on the roles this metabolic pathway may play in cardiovascular disease states, the bioenergetic benefits of myocardial ketone body oxidation, and prospective interactions among ketone body metabolism, obesity, metabolic syndrome, and atherosclerosis. Ketone body metabolism is noninvasively quantifiable in humans and is responsive to nutritional interventions. Therefore, further investigation of this pathway in disease models and in humans may ultimately yield tailored diagnostic strategies and therapies for specific pathological states.
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Affiliation(s)
- David G Cotter
- Department of Medicine, Center for Cardiovascular Research, Washington University, Saint Louis, Missouri 63110, USA
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40
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Kostrominova TY, Reiner DS, Haas RH, Ingermanson R, McDonough PM. Automated methods for the analysis of skeletal muscle fiber size and metabolic type. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:275-332. [PMID: 24016528 DOI: 10.1016/b978-0-12-407694-5.00007-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
It is of interest to quantify the size, shape, and metabolic subtype of skeletal muscle fibers in many areas of biomedical research. To do so, skeletal muscle samples are sectioned transversely to the length of the muscle and labeled for extracellular or membrane proteins to delineate the fiber boundaries and additionally for biomarkers related to function or metabolism. The samples are digitally photographed and the fibers "outlined" for quantification of fiber cross-sectional area (CSA) using pointing devices interfaced to a computer, which is tedious, prone to error, and can be nonobjective. Here, we review methods for characterizing skeletal muscle fibers and describe new automated techniques, which rapidly quantify CSA and biomarkers. We discuss the applications of these methods to the characterization of mitochondrial dysfunctions, which underlie a variety of human afflictions, and we present a novel approach, utilizing images from the online Human Protein Atlas to predict relationships between fiber-specific protein expression, function, and metabolism.
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Navarro-Sastre A, Tort F, Garcia-Villoria J, Pons MR, Nascimento A, Colomer J, Campistol J, Yoldi ME, López-Gallardo E, Montoya J, Unceta M, Martinez MJ, Briones P, Ribes A. Mitochondrial DNA depletion syndrome: new descriptions and the use of citrate synthase as a helpful tool to better characterise the patients. Mol Genet Metab 2012; 107:409-15. [PMID: 22980518 DOI: 10.1016/j.ymgme.2012.08.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 08/25/2012] [Indexed: 01/21/2023]
Abstract
Mitochondrial DNA depletion syndrome (MDS) is a clinically heterogeneous group of mitochondrial disorders characterised by a quantitative reduction of the mitochondrial DNA copy number. Three main clinical forms of MDS: myopathic, encephalomyopathic and hepatocerebral have been defined, although patients may present with other MDS associated clinical symptoms and signs that cover a wide spectrum of onset age and disease. We studied 52 paediatric individuals suspected to have MDS. These patients have been divided into three different groups, and the appropriate MDS genes have been screened according to their clinical and biochemical phenotypes. Mutational study of DGUOK, MPV17, SUCLA2, SUCLG1 and POLG allowed us to identify 3 novel mutations (c.1048G>A and c.1049G>T in SUCLA2 and c.531+4A>T in SUCLG1) and 7 already known mutations in 10 patients (8 families). Seventeen patients presented with mtDNA depletion in liver or muscle, but the cause of mtDNA depletion still remains unknown in 8 of them. When possible, we quantified mtDNA/nDNA and CS activity in the same tissue sample, providing an additional tool for the study of MDS. The ratio (mtDNA/nDNA)/CS has shed some light in the discrepant results between the mtDNA copy number and the enzymatic respiratory chain activities of some cases.
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Affiliation(s)
- Aleix Navarro-Sastre
- Division of Inborn Errors of Metabolism, Department of Biochemistry and Molecular Genetics, Hospital Clinic, Instituto de Investigación Biomédica Pi Sunyer, 08028 Barcelona, Spain
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Kotarsky H, Keller M, Davoudi M, Levéen P, Karikoski R, Enot DP, Fellman V. Metabolite profiles reveal energy failure and impaired beta-oxidation in liver of mice with complex III deficiency due to a BCS1L mutation. PLoS One 2012; 7:e41156. [PMID: 22829922 PMCID: PMC3400604 DOI: 10.1371/journal.pone.0041156] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/18/2012] [Indexed: 12/11/2022] Open
Abstract
Background & Aims Liver is a target organ in many mitochondrial disorders, especially if the complex III assembly factor BCS1L is mutated. To reveal disease mechanism due to such mutations, we have produced a transgenic mouse model with c.232A>G mutation in Bcs1l, the causative mutation for GRACILE syndrome. The homozygous mice develop mitochondrial hepatopathy with steatosis and fibrosis after weaning. Our aim was to assess cellular mechanisms for disease onset and progression using metabolomics. Methods With mass spectrometry we analyzed metabolite patterns in liver samples obtained from homozygotes and littermate controls of three ages. As oxidative stress might be a mechanism for mitochondrial hepatopathy, we also assessed H2O2 production and expression of antioxidants. Results Homozygotes had a similar metabolic profile at 14 days of age as controls, with the exception of slightly decreased AMP. At 24 days, when hepatocytes display first histopathological signs, increases in succinate, fumarate and AMP were found associated with impaired glucose turnover and beta-oxidation. At end stage disease after 30 days, these changes were pronounced with decreased carbohydrates, high levels of acylcarnitines and amino acids, and elevated biogenic amines, especially putrescine. Signs of oxidative stress were present in end-stage disease. Conclusions The findings suggest an early Krebs cycle defect with increases of its intermediates, which might play a role in disease onset. During disease progression, carbohydrate and fatty acid metabolism deteriorate leading to a starvation-like condition. The mouse model is valuable for further investigations on mechanisms in mitochondrial hepatopathy and for interventions.
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Affiliation(s)
- Heike Kotarsky
- Department of Pediatrics, Clinical Sciences, Lund University, Lund, Sweden
| | - Matthias Keller
- Neonatology, Department of Pediatrics, University Hospital, Essen, Germany
| | - Mina Davoudi
- Department of Pediatrics, Clinical Sciences, Lund University, Lund, Sweden
| | - Per Levéen
- Department of Pediatrics, Clinical Sciences, Lund University, Lund, Sweden
| | - Riitta Karikoski
- Central Pathology Laboratory, Helsinki University Hospital Laboratory Diagnostics, Helsinki, Finland
| | - David P. Enot
- Neonatology, Department of Pediatrics, University Hospital, Essen, Germany
| | - Vineta Fellman
- Department of Pediatrics, Clinical Sciences, Lund University, Lund, Sweden
- Children’s Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Folkhälsan Research Center, Helsinki, Finland
- * E-mail:
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