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Bornstein R, Mulholland MT, Sedensky M, Morgan P, Johnson SC. Glutamine metabolism in diseases associated with mitochondrial dysfunction. Mol Cell Neurosci 2023; 126:103887. [PMID: 37586651 PMCID: PMC10773532 DOI: 10.1016/j.mcn.2023.103887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/10/2023] [Accepted: 08/13/2023] [Indexed: 08/18/2023] Open
Abstract
Mitochondrial dysfunction can arise from genetic defects or environmental exposures and impact a wide range of biological processes. Among these are metabolic pathways involved in glutamine catabolism, anabolism, and glutamine-glutamate cycling. In recent years, altered glutamine metabolism has been found to play important roles in the pathologic consequences of mitochondrial dysfunction. Glutamine is a pleiotropic molecule, not only providing an alternate carbon source to glucose in certain conditions, but also playing unique roles in cellular communication in neurons and astrocytes. Glutamine consumption and catabolic flux can be significantly altered in settings of genetic mitochondrial defects or exposure to mitochondrial toxins, and alterations to glutamine metabolism appears to play a particularly significant role in neurodegenerative diseases. These include primary mitochondrial diseases like Leigh syndrome (subacute necrotizing encephalopathy) and MELAS (mitochondrial myopathy with encephalopathy, lactic acidosis, and stroke-like episodes), as well as complex age-related neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Pharmacologic interventions targeting glutamine metabolizing and catabolizing pathways appear to provide some benefits in cell and animal models of these diseases, indicating glutamine metabolism may be a clinically relevant target. In this review, we discuss glutamine metabolism, mitochondrial disease, the impact of mitochondrial dysfunction on glutamine metabolic processes, glutamine in neurodegeneration, and candidate targets for therapeutic intervention.
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Affiliation(s)
- Rebecca Bornstein
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA
| | - Michael T Mulholland
- Department of Applied Sciences, Translational Bioscience, Northumbria University, Newcastle, UK
| | - Margaret Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, USA
| | - Phil Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, USA
| | - Simon C Johnson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, USA; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, USA; Department of Neurology, University of Washington, Seattle, USA; Department of Applied Sciences, Translational Bioscience, Northumbria University, Newcastle, UK.
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Huisman TAGM, Kralik SF, Desai NK, Serrallach BL, Orman G. Neuroimaging of primary mitochondrial disorders in children: A review. J Neuroimaging 2022; 32:191-200. [PMID: 35107193 DOI: 10.1111/jon.12976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/19/2022] [Accepted: 01/22/2022] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial disorders represent a diverse and complex group of entities typified by defective energy metabolism. The mitochondrial oxidative phosphorylation system is typically impaired, which is the predominant source of energy production. Because mitochondria are present in nearly all organs, multiple systems may be affected including the central nervous system, skeletal muscles, kidneys, and liver. In particular, those organs that are metabolically active with high energy demands are explicitly vulnerable. Initial diagnostic work up relies on a detailed evaluation of clinical symptoms including physical examination as well as a comprehensive review of the evolution of symptoms over time, relation to possible "triggering" events (eg, fever, infection), blood workup, and family history. High-end neuroimaging plays a pivotal role in establishing diagnosis, narrowing differential diagnosis, monitoring disease progression, and predicting prognosis. The pattern and characteristics of the neuroimaging findings are often highly suggestive of a mitochondrial disorder; unfortunately, in many cases the wide variability of involved metabolic processes prevents a more specific subclassification. Consequently, additional diagnostic steps including muscle biopsy, metabolic workup, and genetic tests are necessary. In the current manuscript, basic concepts of energy production, genetics, and inheritance patterns are reviewed. In addition, the imaging findings of several illustrative mitochondrial disorders are presented to familiarize the involved physicians with pediatric mitochondrial disorders. In addition, the significance of spinal cord imaging and the value of "reversed image-based discovery" for the recognition and correct (re-)classification of mitochondrial disorders is discussed.
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Affiliation(s)
- Thierry A G M Huisman
- Edward B. Singleton Department of Radiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
| | - Stephen F Kralik
- Edward B. Singleton Department of Radiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
| | - Nilesh K Desai
- Edward B. Singleton Department of Radiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
| | - Bettina L Serrallach
- Edward B. Singleton Department of Radiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
| | - Gunes Orman
- Edward B. Singleton Department of Radiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
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Gayathri N, Deepha S, Sharma S. Diagnosis of primary mitochondrial disorders -Emphasis on myopathological aspects. Mitochondrion 2021; 61:69-84. [PMID: 34592422 DOI: 10.1016/j.mito.2021.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/03/2021] [Accepted: 09/22/2021] [Indexed: 12/29/2022]
Abstract
Mitochondrial disorders are one of the most common neurometabolic disorders affecting all age groups. The phenotype-genotype heterogeneity in these disorders can be attributed to the dual genetic control on mitochondrial functions, posing a challenge for diagnosis. Though the advancement in the high-throughput sequencing and other omics platforms resulted in a "genetics-first" approach, the muscle biopsy remains the benchmark in most of the mitochondrial disorders. This review focuses on the myopathological aspects of primary mitochondrial disorders. The utility of muscle biopsy is not limited to analyse the structural abnormalities; rather it also proves to be a potential tool to understand the deranged sub-cellular functions.
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Affiliation(s)
- Narayanappa Gayathri
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India.
| | - Sekar Deepha
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
| | - Shivani Sharma
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
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de Beaurepaire I, Grévent D, Rio M, Desguerre I, de Lonlay P, Levy R, Dangouloff-Ros V, Bonnefont JP, Barcia G, Funalot B, Besmond C, Metodiev MD, Ruzzenente B, Assouline Z, Munnich A, Rötig A, Boddaert N. High predictive value of brain MRI imaging in primary mitochondrial respiratory chain deficiency. J Med Genet 2018; 55:378-383. [DOI: 10.1136/jmedgenet-2017-105094] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/12/2017] [Accepted: 12/29/2017] [Indexed: 01/09/2023]
Abstract
BackgroundBecause the mitochondrial respiratory chain (RC) is ubiquitous, its deficiency can theoretically give rise to any symptom in any organ or tissue at any age with any mode of inheritance, owing to the twofold genetic origin of respiratory enzyme machinery, that is, nuclear and mitochondrial. Not all respiratory enzyme deficiencies are primary and secondary or artefactual deficiency is frequently observed, leading to a number of misleading conclusions and inappropriate investigations in clinical practice. This study is aimed at investigating the potential role of brain MRI in distinguishing primary RC deficiency from phenocopies and other aetiologies.MethodsStarting from a large series of 189 patients (median age: 3.5 years (8 days–56 years), 58% males) showing signs of RC enzyme deficiency, for whom both brain MRIs and disease-causing mutations were available, we retrospectively studied the positive predictive value (PPV) and the positive likelihood ratio (LR+) of brain MRI imaging and its ability to discriminate between two groups: primary deficiency of the mitochondrial RC machinery and phenocopies.ResultsDetection of (1) brainstem hyperintensity with basal ganglia involvement (P≤0.001) and (2) lactate peak with either brainstem or basal ganglia hyperintensity was highly suggestive of primary RC deficiency (P≤0.01). Fourteen items had a PPV>95% and LR+ was greater than 9 for seven signs. Biallelic SLC19A3 mutations represented the main differential diagnosis. Non-significant differences between the two groups were found for cortical/subcortical atrophy, leucoencephalopathy and involvement of caudate nuclei, spinothalamic tract and corpus callosum.ConclusionBased on these results and owing to invasiveness of skeletal muscle biopsies and cost of high-throughput DNA sequencing, we suggest giving consideration to brain MRI imaging as a diagnostic marker and an informative investigation to be performed in patients showing signs of RC enzyme deficiency.
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Phadke R. Myopathology of Adult and Paediatric Mitochondrial Diseases. J Clin Med 2017; 6:jcm6070064. [PMID: 28677615 PMCID: PMC5532572 DOI: 10.3390/jcm6070064] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 06/21/2017] [Accepted: 06/28/2017] [Indexed: 01/09/2023] Open
Abstract
Mitochondria are dynamic organelles ubiquitously present in nucleated eukaryotic cells, subserving multiple metabolic functions, including cellular ATP generation by oxidative phosphorylation (OXPHOS). The OXPHOS machinery comprises five transmembrane respiratory chain enzyme complexes (RC). Defective OXPHOS gives rise to mitochondrial diseases (mtD). The incredible phenotypic and genetic diversity of mtD can be attributed at least in part to the RC dual genetic control (nuclear DNA (nDNA) and mitochondrial DNA (mtDNA)) and the complex interaction between the two genomes. Despite the increasing use of next-generation-sequencing (NGS) and various omics platforms in unravelling novel mtD genes and pathomechanisms, current clinical practice for investigating mtD essentially involves a multipronged approach including clinical assessment, metabolic screening, imaging, pathological, biochemical and functional testing to guide molecular genetic analysis. This review addresses the broad muscle pathology landscape including genotype–phenotype correlations in adult and paediatric mtD, the role of immunodiagnostics in understanding some of the pathomechanisms underpinning the canonical features of mtD, and recent diagnostic advances in the field.
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Affiliation(s)
- Rahul Phadke
- Division of Neuropathology, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London WC1N 3BG, UK.
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK.
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Cruz S, Taipa R, Nogueira C, Pereira C, Almeida LS, Neiva R, Geraldes T, Guimarães A, Melo‐Pires M, Vilarinho L. Clinical, biochemical, molecular, and histological features of 65 Portuguese patients with mitochondrial disorders. Muscle Nerve 2017; 56:868-872. [DOI: 10.1002/mus.25593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Simão Cruz
- Neurology DepartmentHospital Prof. Doutor Fernando FonsecaIC 19, 2720‐276, Amadora Portugal
| | - Ricardo Taipa
- Neuropathology UnitHospital Santo António / Centro Hospitalar do PortoPorto Portugal
| | - Célia Nogueira
- Newborn screening, Metabolism and Genetics Unit, Human Genetics DepartmentDr. Ricardo Jorge National Health InstitutePorto Portugal
| | - Cristina Pereira
- Newborn screening, Metabolism and Genetics Unit, Human Genetics DepartmentDr. Ricardo Jorge National Health InstitutePorto Portugal
| | - Lígia S. Almeida
- Newborn screening, Metabolism and Genetics Unit, Human Genetics DepartmentDr. Ricardo Jorge National Health InstitutePorto Portugal
| | - Raquel Neiva
- Newborn screening, Metabolism and Genetics Unit, Human Genetics DepartmentDr. Ricardo Jorge National Health InstitutePorto Portugal
| | - Tiago Geraldes
- Neurology DepartmentHospital Garcia de OrtaAlmada Portugal
| | - António Guimarães
- Neuropathology UnitHospital Santo António / Centro Hospitalar do PortoPorto Portugal
| | - Manuel Melo‐Pires
- Neuropathology UnitHospital Santo António / Centro Hospitalar do PortoPorto Portugal
| | - Laura Vilarinho
- Newborn screening, Metabolism and Genetics Unit, Human Genetics DepartmentDr. Ricardo Jorge National Health InstitutePorto Portugal
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Whitehead MT, Lee B, Gropman A. Lesional perfusion abnormalities in Leigh disease demonstrated by arterial spin labeling correlate with disease activity. Pediatr Radiol 2016; 46:1309-16. [PMID: 27043731 DOI: 10.1007/s00247-016-3616-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/04/2016] [Accepted: 03/18/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Leigh disease is a metabolic disorder of the mitochondrial respiratory chain culminating in symmetrical necrotizing lesions in the deep gray nuclei or brainstem. Apart from classic gliotic/necrotic lesions, small-vessel proliferation is also characteristic on histopathology. We have observed lesional hyperperfusion on arterial spin-labeling (ASL) sequence in children with Leigh disease. OBJECTIVE In this cross-sectional analysis, we evaluated lesional ASL perfusion characteristics in children with Leigh syndrome. MATERIALS AND METHODS We searched the imaging database from an academic children's hospital for "arterial spin labeling, perfusion, necrosis, lactate, and Leigh" to build a cohort of children for retrospective analysis. We reviewed each child's medical record to confirm a diagnosis of Leigh disease, excluding exams with artifact, technical limitations, and without ASL images. We evaluated the degree and extent of cerebral blood flow and relationship to brain lesions. Images were compared to normal exams from an aged-matche cohort. RESULTS The database search yielded 45 exams; 30 were excluded. We evaluated 15 exams from 8 children with Leigh disease and 15 age-matched normal exams. In general, Leigh brain perfusion ranged from hyperintense (n=10) to hypointense (n=5). Necrotic lesions appeared hypointense/hypoperfused. Active lesions with associated restricted diffusion demonstrated hyperperfusion. ASL perfusion patterns differed significantly from those on age-matched normal studies (P=<.0001). Disease activity positively correlated with cerebral deep gray nuclei hyperperfusion (P=0.0037) and lesion grade (P=0.0256). CONCLUSION Children with Leigh disease have abnormal perfusion of brain lesions. Hyperperfusion can be found in active brain lesions, possibly associated with small-vessel proliferation characteristic of the disease.
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Affiliation(s)
- Matthew T Whitehead
- Department of Radiology, Children's National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010, USA. .,The George Washington University School of Medicine, Washington, DC, USA.
| | - Bonmyong Lee
- Department of Radiology, The Johns Hopkins Medical Institute, Baltimore, MD, USA
| | - Andrea Gropman
- The George Washington University School of Medicine, Washington, DC, USA.,Department of Neurology, Children's National Medical Center, Washington, DC, USA
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Finsterer J, Zarrouk-Mahjoub S. Is chronic fatigue syndrome truly associated with haplogroups or mtDNA single nucleotide polymorphisms? J Transl Med 2016; 14:182. [PMID: 27317438 PMCID: PMC4912808 DOI: 10.1186/s12967-016-0939-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/03/2016] [Indexed: 11/30/2022] Open
Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180, Vienna, Austria.
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Koch J, Feichtinger RG, Freisinger P, Pies M, Schrödl F, Iuso A, Sperl W, Mayr JA, Prokisch H, Haack TB. Disturbed mitochondrial and peroxisomal dynamics due to loss of MFF causes Leigh-like encephalopathy, optic atrophy and peripheral neuropathy. J Med Genet 2016; 53:270-8. [PMID: 26783368 DOI: 10.1136/jmedgenet-2015-103500] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/12/2015] [Indexed: 11/03/2022]
Abstract
BACKGROUND Mitochondria are dynamic organelles which undergo continuous fission and fusion to maintain their diverse cellular functions. Components of the fission machinery are partly shared between mitochondria and peroxisomes, and inherited defects in two such components (dynamin-related protein (DRP1) and ganglioside-induced differentiation-associated protein 1 (GDAP1)) have been associated with human disease. Deficiency of a third component (mitochondrial fission factor, MFF) was recently reported in one index patient, rendering MFF another candidate disease gene within the expanding field of mitochondrial and peroxisomal dynamics. Here we investigated three new patients from two families with pathogenic mutations in MFF. METHODS The patients underwent clinical examination, brain MRI, and biochemical, cytological and molecular analyses, including exome sequencing. RESULTS The patients became symptomatic within the first year of life, exhibiting seizures, developmental delay and acquired microcephaly. Dysphagia, spasticity and optic and peripheral neuropathy developed subsequently. Brain MRI showed Leigh-like patterns with bilateral changes of the basal ganglia and subthalamic nucleus, suggestive of impaired mitochondrial energy metabolism. However, activities of mitochondrial respiratory chain complexes were found to be normal in skeletal muscle. Exome sequencing revealed three different biallelic loss-of-function variants in MFF in both index cases. Western blot studies of patient-derived fibroblasts indicated normal content of mitochondria and peroxisomes, whereas immunofluorescence staining revealed elongated mitochondria and peroxisomes. Furthermore, increased mitochondrial branching and an abnormal distribution of fission-mediating DRP1 were observed. CONCLUSIONS Our findings establish MFF loss of function as a cause of disturbed mitochondrial and peroxisomal dynamics associated with early-onset Leigh-like basal ganglia disease. We suggest that, even if laboratory findings are not indicative of mitochondrial or peroxisomal dysfunction, the co-occurrence of optic and/or peripheral neuropathy with seizures warrants genetic testing for MFF mutations.
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Affiliation(s)
- Johannes Koch
- Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - René G Feichtinger
- Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Peter Freisinger
- Department of Pediatrics, Kreisklinken Reutlingen, Reutlingen, Germany
| | - Mechthild Pies
- Social Paediatric Center, Klinikum Frankfurt-Höchst, Frankfurt am Main, Germany
| | - Falk Schrödl
- Department of Ophthalmology and Optometry, Department of Anatomy, Department of Laboratory Medicine (HW), and First Department of Internal Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Arcangela Iuso
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Wolfgang Sperl
- Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Johannes A Mayr
- Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Tobias B Haack
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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Ahmed N, Ronchi D, Comi GP. Genes and Pathways Involved in Adult Onset Disorders Featuring Muscle Mitochondrial DNA Instability. Int J Mol Sci 2015; 16:18054-76. [PMID: 26251896 PMCID: PMC4581235 DOI: 10.3390/ijms160818054] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 12/31/2022] Open
Abstract
Replication and maintenance of mtDNA entirely relies on a set of proteins encoded by the nuclear genome, which include members of the core replicative machinery, proteins involved in the homeostasis of mitochondrial dNTPs pools or deputed to the control of mitochondrial dynamics and morphology. Mutations in their coding genes have been observed in familial and sporadic forms of pediatric and adult-onset clinical phenotypes featuring mtDNA instability. The list of defects involved in these disorders has recently expanded, including mutations in the exo-/endo-nuclease flap-processing proteins MGME1 and DNA2, supporting the notion that an enzymatic DNA repair system actively takes place in mitochondria. The results obtained in the last few years acknowledge the contribution of next-generation sequencing methods in the identification of new disease loci in small groups of patients and even single probands. Although heterogeneous, these genes can be conveniently classified according to the pathway to which they belong. The definition of the molecular and biochemical features of these pathways might be helpful for fundamental knowledge of these disorders, to accelerate genetic diagnosis of patients and the development of rational therapies. In this review, we discuss the molecular findings disclosed in adult patients with muscle pathology hallmarked by mtDNA instability.
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Affiliation(s)
- Naghia Ahmed
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
| | - Dario Ronchi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
| | - Giacomo Pietro Comi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
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Bhatnagar M, Shorvon S. Genetic mutations associated with status epilepticus. Epilepsy Behav 2015; 49:104-10. [PMID: 25982265 DOI: 10.1016/j.yebeh.2015.04.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/06/2015] [Accepted: 04/07/2015] [Indexed: 01/28/2023]
Abstract
This paper reports the results of a preliminary search of the literature aimed at identifying the genetic mutations reported to be strongly associated with status epilepticus. Genetic mutations were selected for inclusion if status epilepticus was specifically mentioned as a consequence of the mutation in standard genetic databases or in a case report or review article. Mutations in 122 genes were identified. The genetic mutations identified were found in only rare conditions (sometimes vanishingly rare) and mostly in infants and young children with multiple other handicaps. Most of the genetic mutations can be subdivided into those associated with cortical dysplasias, inborn errors of metabolism, mitochondrial disease, or epileptic encephalopathies and childhood syndromes. There are no identified 'pure status epilepticus genes'. The range of genes underpinning status epilepticus differs in many ways from the range of genes underpinning epilepsy, which suggests that the processes underpinning status epilepticus differ from those underpinning epilepsy. It has been frequently postulated that status epilepticus is the result of a failure of 'seizure termination mechanisms', but the wide variety of genes affecting very diverse biochemical pathways identified in this survey makes any unitary cause unlikely. The genetic influences in status epilepticus are likely to involve a wide range of mechanisms, some related to development, some to cerebral energy production, some to diverse altered biochemical pathways, some to transmitter and membrane function, and some to defects in networks or systems. The fact that many of the identified genes are involved with cerebral development suggests that status epilepticus might often be a system or network phenomenon. To date, there are very few genes identified which are associated with adult-onset status epilepticus (except in those with preexisting neurological damage), and this is disappointing as the cause of many adult-onset status epilepticus cases remains obscure. It has been suggested that idiopathic adult-onset status epilepticus might often have an immunological cause but no gene mutations which relate to immunological mechanisms were identified. Overall, the clinical utility of what is currently known about the genetics of status epilepticus is slight and the findings have had little impact on clinical treatment despite what has been a very large investment in money and time. New genetic technologies may result in the identification of further genes, but if the identified genetic defects confer only minor susceptibility, this is unlikely to influence therapy. It is also important to recognize that genetics has social implications in a way that other areas of science do not. This article is part of a Special Issue entitled "Status Epilepticus".
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Affiliation(s)
- M Bhatnagar
- UCL Institute of Neurology, University College London, UK
| | - S Shorvon
- UCL Institute of Neurology, University College London, UK.
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12
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Gardner A, Åstrand D, Öberg J, Jacobsson H, Jonsson C, Larsson S, Pagani M. Towards mapping the brain connectome in depression: functional connectivity by perfusion SPECT. Psychiatry Res 2014; 223:171-7. [PMID: 24931481 DOI: 10.1016/j.pscychresns.2014.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 05/08/2014] [Accepted: 05/14/2014] [Indexed: 12/29/2022]
Abstract
Several studies have demonstrated altered brain functional connectivity in the resting state in depression. However, no study has investigated interregional networking in patients with persistent depressive disorder (PDD). The aim of this study was to assess differences in brain perfusion distribution and connectivity between large groups of patients and healthy controls. Participants comprised 91 patients with PDD and 65 age- and sex-matched healthy controls. Resting state perfusion was investigated by single photon emission computed tomography, and group differences were assessed by Statistical Parametric Mapping. Brain connectivity was explored through a voxel-wise interregional correlation analysis using as covariate of interest the normalized values of clusters of voxels in which perfusion differences were found in group analysis. Significantly increased regional brain perfusion distribution covering a large part of the cerebellum was observed in patients as compared with controls. Patients showed a significant negative functional connectivity between the cerebellar cluster and caudate, bilaterally. This study demonstrated inverse relative perfusion between the cerebellum and the caudate in PDD. Functional uncoupling may be associated with a dysregulation between the role of the cerebellum in action control and of the caudate in action selection, initiation and decision making in the patients. The potential impact of the resting state condition and the possibility of mitochondrial impairment are discussed.
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Affiliation(s)
- Ann Gardner
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Järva Psychiatric Out-patient Clinic, Stockholm, Sweden
| | - Disa Åstrand
- Section of Imaging Physics, Solna Nuclear Medicine, Department of Medical Physics, Karolinska University Hospital, Stockholm, Sweden
| | - Johanna Öberg
- Section of Imaging Physics, Department of Hospital Physics, Karolinska University Hospital, Stockholm, Sweden
| | - Hans Jacobsson
- Department of Nuclear Medicine, Karolinska Hospital, Stockholm, Sweden
| | - Cathrine Jonsson
- Section of Imaging Physics, Solna Nuclear Medicine, Department of Medical Physics, Karolinska University Hospital, Stockholm, Sweden
| | - Stig Larsson
- Department of Nuclear Medicine, Karolinska Hospital, Stockholm, Sweden
| | - Marco Pagani
- Department of Nuclear Medicine, Karolinska Hospital, Stockholm, Sweden; Institute of Cognitive Sciences and Technologies, Consiglio Nazionale delle Ricerche (CNR), Rome, Italy.
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Platt J, Cox R, Enns GM. Points to consider in the clinical use of NGS panels for mitochondrial disease: an analysis of gene inclusion and consent forms. J Genet Couns 2014; 23:594-603. [PMID: 24399097 DOI: 10.1007/s10897-013-9683-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/12/2013] [Indexed: 12/21/2022]
Abstract
Mitochondrial next generation sequencing (NGS) panels offer single-step analysis of the numerous nuclear genes involved in the structure, function, and maintenance of mitochondria. However, the complexities of mitochondrial biology and genetics raise points for consideration in clinical use of these tests. To understand the current status of mitochondrial genetic testing, we assessed the gene offerings and consent forms of mitochondrial NGS panels available from seven US-based clinical laboratories. The NGS panels varied markedly in number of genes (101-1204 genes), and the proportion of genes causing "classic" mitochondrial diseases and their phenocopies ranged widely between labs (18 %-94 % of panel contents). All panels included genes not associated with classic mitochondrial diseases (6 %-28 % of panel contents), including genes causing adult-onset neurodegenerative disorders, cancer predisposition, and other genetic syndromes or inborn errors of metabolism. Five of the panels included genes that are not listed in OMIM to be associated with a disease phenotype (5 %-49 % of panel contents). None of the consent documents reviewed had options for patient preference regarding receipt of incidental findings. These findings raise points of discussion applicable to mitochondrial diagnostics, but also to the larger arenas of exome and genome sequencing, including the need to consider the boundaries between clinical and research testing, the necessity of appropriate informed consent, and the responsibilities of clinical laboratories and clinicians. Based on these findings, we recommend careful evaluation by laboratories of the genes offered on NGS panels, clear communication of the predicted phenotypes, and revised consent forms to allow patients to make choices about receiving incidental findings. We hope that our analysis and recommendations will help to maximize the considerable clinical utility of NGS panels for the diagnosis of mitochondrial disease.
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Affiliation(s)
- Julia Platt
- Department of Pediatrics, Lucile Packard Children's Hospital, Stanford University, 300 Pasteur Drive, H-315, Stanford, CA, 94305, USA,
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14
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Araujo B, Torres L, Stein M, Cabral FR, Herai R, Okamoto O, Cavalheiro E. Decreased expression of proteins involved in energy metabolism in the hippocampal granular layer of rats submitted to the pilocarpine epilepsy model. Neurosci Lett 2013; 561:46-51. [PMID: 24373985 DOI: 10.1016/j.neulet.2013.12.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 12/01/2013] [Accepted: 12/17/2013] [Indexed: 11/18/2022]
Abstract
Long-term structural and functional changes in the hippocampus have been identified as the primary physiopathological basis for temporal lobe epilepsy. These changes include reactive gliosis and granule cell axonal sprouting within the dentate gyrus. The intimate mechanisms of these changes are beginning to be revealed. Here, we show the possibility of using laser capture microdissection (LCM) to isolate the dentate granular cell layer of Wistar rats submitted to the pilocarpine model of epilepsy. Using two-dimensional gel electrophoresis (2-D PAGE) and mass spectrometry for laser-captured cells, we identified molecular events that could be altered as part of the epileptic pathogenic process. According to our results, eight proteins related to energy metabolism were differentially expressed between both the control and pilocarpine-treated animals. These results provide, for the first time, new molecular insights into the altered protein profile of the epileptogenic dentate gyrus and can contribute to a better understanding of the phenomena involved in the genesis and maintenance of the epileptic state.
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Affiliation(s)
- Bruno Araujo
- Neurologia Experimental - Escola Paulista de Medicina/Universidade Federal de São Paulo, São Paulo, SP, Brazil; University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA, USA.
| | - Laila Torres
- Neurologia Experimental - Escola Paulista de Medicina/Universidade Federal de São Paulo, São Paulo, SP, Brazil; Hospital Israelita Albert Einstein - Instituto do Cérebro, São Paulo, SP, Brazil; University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA, USA
| | - Mariana Stein
- Laboratório de Biologia Molecular de Parasitas - Escola Paulista de Medicina/Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Francisco Romero Cabral
- Hospital Israelita Albert Einstein - Instituto do Cérebro, São Paulo, SP, Brazil; Faculdade de Ciências Médicas da Santa Casa de São Paulo, São Paulo, SP, Brazil
| | - Roberto Herai
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA, USA
| | - Oswaldo Okamoto
- Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, USP, Instituto de Biociências, São Paulo, SP, Brazil
| | - Esper Cavalheiro
- Neurologia Experimental - Escola Paulista de Medicina/Universidade Federal de São Paulo, São Paulo, SP, Brazil
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