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Gupta V, Jolly B, Bhoyar RC, Divakar MK, Jain A, Mishra A, Senthivel V, Imran M, Scaria V, Sivasubbu S. Spectrum of rare and common mitochondrial DNA variations from 1029 whole genomes of self-declared healthy individuals from India. Comput Biol Chem 2024; 112:108118. [PMID: 38878606 DOI: 10.1016/j.compbiolchem.2024.108118] [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: 09/08/2023] [Revised: 05/21/2024] [Accepted: 06/04/2024] [Indexed: 09/13/2024]
Abstract
Mitochondrial disorders are a class of heterogeneous disorders caused by genetic variations in the mitochondrial genome (mtDNA) as well as the nuclear genome. The spectrum of mtDNA variants remains unexplored in the Indian population. In the present study, we have cataloged 2689 high confidence single nucleotide variants, small insertions and deletions in mtDNA in 1029 healthy Indian individuals. We found a major proportion (76.5 %) of the variants being rare (AF<=0.005) in the studied population. Intriguingly, we found two 'confirmed' pathogenic variants (m.1555 A>G and m.14484 T>C) with a frequency of ∼1 in 250 individuals in our dataset. The high carrier frequency underscores the need for screening of the mtDNA pathogenic mutations in newborns in India. Interestingly, our analysis also revealed 202 variants in our dataset which have been 'reported' in disease cases as per the MITOMAP database. Additionally, we found the frequency of haplogroup M (52.2 %) to be the highest among all the 18 top-level haplogroups found in our dataset. In comparison to the global population datasets, 20 unique mtDNA variants are found in the Indian population. We hope the whole genome sequencing based compendium of mtDNA variants along with their allele frequencies and heteroplasmy levels in the Indian population will drive additional genome scale studies for mtDNA. Furthermore, the identification of clinically relevant variants in our dataset will aid in better clinical interpretation of the variants in mitochondrial disorders.
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Affiliation(s)
- Vishu Gupta
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Bani Jolly
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rahul C Bhoyar
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | - Mohit Kumar Divakar
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Abhinav Jain
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Anushree Mishra
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | - Vigneshwar Senthivel
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Mohamed Imran
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Vinod Scaria
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
| | - Sridhar Sivasubbu
- CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Tsai NC, Liou CW, Cheng YH, Lien HT, Lin TL, Lin TK, Lan MY, Hung PL, Wang TJ, Lee CH, Liang YC, Lan KC. The establishment of a molecular diagnostic platform for mitochondrial diseases: from conventional to next-generation sequencing. Biomed J 2024:100770. [PMID: 39048080 DOI: 10.1016/j.bj.2024.100770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 06/14/2024] [Accepted: 07/18/2024] [Indexed: 07/27/2024] Open
Abstract
BACKGROUND The aim of this study was to create a molecular diagnostic platform and establish a diagnostic pipeline for patients highly suspected of mitochondrial disorders. The effectiveness of three methods, namely, traditional restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR), Sanger sequencing for hotspot detection and whole mitochondrial DNA (mtDNA), and third-generation (Nanopore) whole mtDNA sequencing, will be compared in diagnosing patients with suspected primary mitochondrial diseases (PMDs). The strengths and limitations of different methods are also discussed. MATERIAL AND METHODS A single-center prospective cohort study was conducted to validate the diagnostic pipeline for suspected mitochondrial diseases. In the first stage, a PCR-based method with five sets of primers was used to screen for eight hotspots (m.3243A>G, m.3460G>A, m.8344A>G, m.8993T>G, m.9185T>C, m.11778G>A, m.13513G>A, and m.4977deletion) using either RFLP or direct Sanger sequencing. Sanger sequencing was also used to confirm the RFLP-positive samples. In the second stage, for samples with negative screening results for the eight hotspots, mitochondrial whole-genome sequencing was performed using Sanger sequencing or third-generation nanopore sequencing. RESULTS Between June 2020 and May 2023, 30 patients from ages 0 to 63 with clinically suspected mitochondrial disease were enrolled. The positive yield for the diagnosis of PMDs was 8/30=26.7%, and the sensitivity of the heteroplasmy level for the RFLP-based method was approximately 5%. The remaining 22 patients who tested negative at the first stage were tested using Sanger sequencing or the third-generation sequencing Nanopore, and all tested negative for pathological mtDNA mutations. Compared to the Sanger sequencing method, the results of RFLP-PCR were compromised by the limitations of incomplete RFLP enzyme digestion. For whole-genome sequencing of mtDNA, Sanger sequencing, instead of nanopore sequencing, is preferred at our institution because of its cost-effectiveness. CONCLUSIONS In our highly selective cohort, most tested positive in the first stage of the 8 hot spots screen. Sanger sequencing is a conventional and accurate method for mitochondrial disease screening, at least for the most common hot spots in the region. The results revealed that Sanger sequencing is an accurate method with the benefit of being more cost-effective. This integral platform of molecular diagnosis bears the advantages of being relatively low cost and having a shorter reporting time, facilitating crucial identification of patients with clinical evidence of such disorders. This diagnostic flowchart has also been translated into routine clinical use in the tertiary hospital.
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Affiliation(s)
- Ni-Chin Tsai
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung, 80708, Taiwan; Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Menopause and Reproductive Medicine Research, Kaohsiung Chang Gung Memorial Hospital
| | - Chai-Wai Liou
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yin-Hua Cheng
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Menopause and Reproductive Medicine Research, Kaohsiung Chang Gung Memorial Hospital
| | - Hao-Ting Lien
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tzu-Ling Lin
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Center for Menopause and Reproductive Medicine Research, Kaohsiung Chang Gung Memorial Hospital
| | - Tsu-Kung Lin
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Min-Yu Lan
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Pi-Lien Hung
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tzu-Jou Wang
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chen-Hao Lee
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yi-Chih Liang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Kuo-Chung Lan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung, 80708, Taiwan; Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Menopause and Reproductive Medicine Research, Kaohsiung Chang Gung Memorial Hospital; Department of Obstetrics and Gynecology, Jen-Ai Hospital, Taichung 412, Taiwan.
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Chin HL, Lai PS, Tay SKH. A clinical approach to diagnosis and management of mitochondrial myopathies. Neurotherapeutics 2024; 21:e00304. [PMID: 38241155 PMCID: PMC10903095 DOI: 10.1016/j.neurot.2023.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/11/2023] [Indexed: 01/21/2024] Open
Abstract
This paper provides an overview of the different types of mitochondrial myopathies (MM), associated phenotypes, genotypes as well as a practical clinical approach towards disease diagnosis, surveillance, and management. nDNA-related MM are more common in pediatric-onset disease whilst mtDNA-related MMs are more frequent in adults. Genotype-phenotype correlation in MM is challenging due to clinical and genetic heterogeneity. The multisystemic nature of many MMs adds to the diagnostic challenge. Diagnostic approaches utilizing genetic sequencing with next generation sequencing approaches such as gene panel, exome and genome sequencing are available. This aids molecular diagnosis, heteroplasmy detection in MM patients and furthers knowledge of known mitochondrial genes. Precise disease diagnosis can end the diagnostic odyssey for patients, avoid unnecessary testing, provide prognosis, facilitate anticipatory management, and enable access to available therapies or clinical trials. Adjunctive tests such as functional and exercise testing could aid surveillance of MM patients. Management requires a multi-disciplinary approach, systemic screening for comorbidities, cofactor supplementation, avoidance of substances that inhibit the respiratory chain and exercise training. This update of the current understanding on MMs provides practical perspectives on current diagnostic and management approaches for this complex group of disorders.
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Affiliation(s)
- Hui-Lin Chin
- Division of Genetics and Metabolism, Department of Paediatrics, Khoo Teck Puat-National University Children's Medical Institute, National University Hospital, Singapore; Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Stacey Kiat Hong Tay
- Division of Genetics and Metabolism, Department of Paediatrics, Khoo Teck Puat-National University Children's Medical Institute, National University Hospital, Singapore; Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Division of Neurology, Department of Paediatrics, Khoo Teck Puat-National University Children's Medical Institute, National University Hospital, Singapore.
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Ibrahim AH, Rahman NNA, Saifuddeen SM. Mitochondrial Replacement Therapy: An Islamic Perspective. JOURNAL OF BIOETHICAL INQUIRY 2023; 20:485-495. [PMID: 37440155 DOI: 10.1007/s11673-023-10279-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/19/2023] [Indexed: 07/14/2023]
Abstract
Mitochondrial replacement technology (MRT) is an emerging and complex bioethical issue. This treatment aims to eliminate maternal inherited mitochondrial DNA (mtDNA) disorders. For Muslims, its introduction affects every aspect of human life, especially the five essential interests of human beings-namely, religion, life, lineage, intellect, and property. Thus, this technology must be assessed using a comprehensive and holistic approach addressing these human essential interests. Consequently, this article analyses and assesses tri-parent baby technology from the perspective of Maqasidic bioethics-that is, Islamic bioethics based on the framework of Maqasid al-Shariah. Using this analysis, this article suggests that tri-parent baby technology should not be permitted for Muslims due to the existence of third-party cell gametes which lead to lineage mixing and due to the uncertain safety of the therapy itself and because the major aim of the technology is to fulfil the affected couples interest to conceive their own genetically healthy child, not to treat and cure mtDNA disorders sufferers.
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Affiliation(s)
- Abdul Halim Ibrahim
- Programme of Applied Science with Islamic Studies, Academy of Islamic Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Noor Naemah Abdul Rahman
- Department of Fiqh and Usul, Academy of Islamic Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Shaikh Mohd Saifuddeen
- Centre for Science and Environment Studies, Institute of Islamic Understanding Malaysia, 2 Langgak Tunku Off Jalan Tuanku Abdul Halim, 50480, Kuala Lumpur, Malaysia
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5
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Staicu A, Popa-Stanila R, Albu C, Chira A, Constantin R, Boitor-Borza D, Surcel M, Rotar IC, Cruciat G, Muresan D. Neonatal Hemochromatosis: Systematic Review of Prenatal Ultrasound Findings—Is There a Place for MRI in the Diagnostic Process? J Clin Med 2023; 12:jcm12072679. [PMID: 37048762 PMCID: PMC10094906 DOI: 10.3390/jcm12072679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/24/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
Neonatal hemochromatosis (NH) is an uncommon, severe disorder that results in fetal loss or neonatal death due to liver failure. NH is currently regarded as the phenotypic expression of gestational alloimmune liver disease (GALD). The diagnosis of NH-GALD is rarely prenatally established. In addition to providing a systematic review of the prenatal features that are identifiable using ultrasound (US) and MRI, we suggest a prenatal diagnosis algorithm for use in suspected NH during the first affected pregnancy. From a total of 586 database entries identified in PubMed, Google Scholar, and ResearchGate, we selected 18 studies published from 1993 to 2021 that reported maternal medical and obstetric history, prenatal ultrasound findings, and postpartum outcomes. We investigated the ultrasound and MRI features of these studies, along with the outcome due to this condition. A total of 74 cases were identified. The main reported prenatal US finding was fetal growth restriction (FGR) (33%), followed by oligohydramnios (13%) and hydrops fetalis (13%), with 13% cases described as uneventful. Other rare prenatal findings were fetal anemia, ascites, and abnormal fetal liver and spleen. Most pregnancies ended with fetal/perinatal death or therapeutic interruption of pregnancy. Favorable evolution with treatment (ensanguine transfusion and intravenous immunoglobulin (IVIG)) was reported for only 7% of fetuses. Using T2-weighted MRI, fetal extrahepatic siderosis confirmed prenatally in two cases and postnatally in 11 cases. IVIG treatment throughout subsequent pregnancies was found to significantly improve fetal prognosis. MRI should be indicated in selected cases of oligohydramnios, fetal hydrops, fetal hepatomegaly, ascites, or unexplained FGR or anemia after ruling out all other more frequently encountered conditions. MRI can be used to detect iron overload in the liver and extrahepatic siderosis.
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Affiliation(s)
- Adelina Staicu
- 1st Department of Obstetrics and Gynecology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Roxana Popa-Stanila
- Department of Radiology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- Centre of Advanced Research Studies, Emergency County Hospital, IMOGEN, 400006 Cluj-Napoca, Romania
| | - Camelia Albu
- Centre of Advanced Research Studies, Emergency County Hospital, IMOGEN, 400006 Cluj-Napoca, Romania
- Department of Pathology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Alexandra Chira
- Department of Internal Medicine, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 2nd Medical Clinic, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Roxana Constantin
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Dan Boitor-Borza
- 1st Department of Obstetrics and Gynecology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Mihai Surcel
- 1st Department of Obstetrics and Gynecology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Ioana Cristina Rotar
- 1st Department of Obstetrics and Gynecology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Gheorghe Cruciat
- 1st Department of Obstetrics and Gynecology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
| | - Daniel Muresan
- 1st Department of Obstetrics and Gynecology, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- 1st Clinics of Obstetrics and Gynecology Cluj-Napoca, Emergency County Clinical Hospital, 400006 Cluj-Napoca, Romania
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6
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Ng YS, Gorman GS. Stroke-like episodes in adult mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:65-78. [PMID: 36813321 DOI: 10.1016/b978-0-12-821751-1.00005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Stroke-like episode is a paroxysmal neurological manifestation which affects a specific group of patients with mitochondrial disease. Focal-onset seizures, encephalopathy, and visual disturbances are prominent findings associated with stroke-like episodes, with a predilection for the posterior cerebral cortex. The most common cause of stroke-like episodes is the m.3243A>G variant in MT-TL1 gene followed by recessive POLG variants. This chapter aims to review the definition of stroke-like episode and delineate the clinical phenomenology, neuroimaging and EEG findings typically seen in patients. In addition, several lines of evidence supporting neuronal hyper-excitability as the key mechanism of stroke-like episodes are discussed. The management of stroke-like episodes should focus on aggressive seizure management and treatment for concomitant complications such as intestinal pseudo-obstruction. There is no robust evidence to prove the efficacy of l-arginine for both acute and prophylactic settings. Progressive brain atrophy and dementia are the sequalae of recurrent stroke-like episode, and the underlying genotype in part predicts prognosis.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
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7
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Mavraki E, Labrum R, Sergeant K, Alston CL, Woodward C, Smith C, Knowles CVY, Patel Y, Hodsdon P, Baines JP, Blakely EL, Polke J, Taylor RW, Fratter C. Genetic testing for mitochondrial disease: the United Kingdom best practice guidelines. Eur J Hum Genet 2023; 31:148-163. [PMID: 36513735 PMCID: PMC9905091 DOI: 10.1038/s41431-022-01249-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/12/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
Primary mitochondrial disease describes a diverse group of neuro-metabolic disorders characterised by impaired oxidative phosphorylation. Diagnosis is challenging; >350 genes, both nuclear and mitochondrial DNA (mtDNA) encoded, are known to cause mitochondrial disease, leading to all possible inheritance patterns and further complicated by heteroplasmy of the multicopy mitochondrial genome. Technological advances, particularly next-generation sequencing, have driven a shift in diagnostic practice from 'biopsy first' to genome-wide analyses of blood and/or urine DNA. This has led to the need for a reference framework for laboratories involved in mitochondrial genetic testing to facilitate a consistent high-quality service. In the United Kingdom, consensus guidelines have been prepared by a working group of Clinical Scientists from the NHS Highly Specialised Service followed by national laboratory consultation. These guidelines summarise current recommended technologies and methodologies for the analysis of mtDNA and nuclear-encoded genes in patients with suspected mitochondrial disease. Genetic testing strategies for diagnosis, family testing and reproductive options including prenatal diagnosis are outlined. Importantly, recommendations for the minimum levels of mtDNA testing for the most common referral reasons are included, as well as guidance on appropriate referrals and information on the minimal appropriate gene content of panels when analysing nuclear mitochondrial genes. Finally, variant interpretation and recommendations for reporting of results are discussed, focussing particularly on the challenges of interpreting and reporting mtDNA variants.
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Affiliation(s)
- Eleni Mavraki
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Robyn Labrum
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Kate Sergeant
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Charlotte L Alston
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Cathy Woodward
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Conrad Smith
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Charlotte V Y Knowles
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Yogen Patel
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Philip Hodsdon
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Jack P Baines
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Emma L Blakely
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - James Polke
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Robert W Taylor
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Carl Fratter
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
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8
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Ng YS, Lim AZ, Panagiotou G, Turnbull DM, Walker M. Endocrine Manifestations and New Developments in Mitochondrial Disease. Endocr Rev 2022; 43:583-609. [PMID: 35552684 PMCID: PMC9113134 DOI: 10.1210/endrev/bnab036] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Indexed: 11/19/2022]
Abstract
Mitochondrial diseases are a group of common inherited diseases causing disruption of oxidative phosphorylation. Some patients with mitochondrial disease have endocrine manifestations, with diabetes mellitus being predominant but also include hypogonadism, hypoadrenalism, and hypoparathyroidism. There have been major developments in mitochondrial disease over the past decade that have major implications for all patients. The collection of large cohorts of patients has better defined the phenotype of mitochondrial diseases and the majority of patients with endocrine abnormalities have involvement of several other systems. This means that patients with mitochondrial disease and endocrine manifestations need specialist follow-up because some of the other manifestations, such as stroke-like episodes and cardiomyopathy, are potentially life threatening. Also, the development and follow-up of large cohorts of patients means that there are clinical guidelines for the management of patients with mitochondrial disease. There is also considerable research activity to identify novel therapies for the treatment of mitochondrial disease. The revolution in genetics, with the introduction of next-generation sequencing, has made genetic testing more available and establishing a precise genetic diagnosis is important because it will affect the risk for involvement for different organ systems. Establishing a genetic diagnosis is also crucial because important reproductive options have been developed that will prevent the transmission of mitochondrial disease because of mitochondrial DNA variants to the next generation.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Albert Zishen Lim
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Grigorios Panagiotou
- Department of Diabetes and Endocrinology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Mark Walker
- Department of Diabetes and Endocrinology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
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9
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Liu P, Vossaert L. Emerging technologies for prenatal diagnosis: The application of whole genome and RNA sequencing. Prenat Diagn 2022; 42:686-696. [PMID: 35416301 PMCID: PMC10014115 DOI: 10.1002/pd.6146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/10/2022]
Abstract
DNA sequencing technologies for clinical genetic testing have been rapidly evolving in recent years, and steadily become more important within the field of prenatal diagnostics. This review aims to give an overview of recent developments and to describe how they have the potential to fill the gaps of the currently clinically implemented methods for prenatal diagnosis of various genetic disorders. It has been shown for postnatal testing that whole genome sequencing provides a set of added benefits compared to exome sequencing, and it is to be expected that this will be the case for prenatal testing as well. RNA-sequencing, already used postnatally, can provide valuable complementary data to DNA-based testing, and aid in variant interpretation. While not ready for clinical implementation, emerging technologies such as long-read and Hi-C sequencing analyses might add to the toolbox for interpreting the expanding genetic data sets generated by genome-wide sequencing. Lastly, we also discuss some more practical implications of introducing these emerging technologies, which generate larger and larger genomic data sets, in the prenatal field.
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Affiliation(s)
- Pengfei Liu
- Baylor College of Medicine and Baylor Genetics, Houston, Texas, USA
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10
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Hou Y, Zhao X, Xie Z, Yu M, Lv H, Zhang W, Yuan Y, Wang Z. Novel and recurrent nuclear gene variations in a cohort of Chinese progressive external ophthalmoplegia patients with multiple mtDNA deletions. Mol Genet Genomic Med 2022; 10:e1921. [PMID: 35289132 PMCID: PMC9034679 DOI: 10.1002/mgg3.1921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/30/2021] [Accepted: 02/25/2022] [Indexed: 11/07/2022] Open
Abstract
Objectives This study aimed to investigate the clinical and genetic spectrum in Chinese patients with multiple mtDNA deletions presenting with autosomal‐inherited mitochondrial progressive external ophthalmoplegia (PEO). Methods Long‐range polymerase chain reaction and massively parallel sequencing of the mitochondrial genome were performed to detect deletions in muscle mtDNA of 274 unrelated families. Then, targeted next generation sequencing was used to detect nuclear gene variations in patients with multiple mtDNA deletions. Results A total of 40 Chinese PEO patients (10 males and 30 females) from 20 families were found to have multiple mtDNA deletions in this study, and the median age at onset was 35 (1–70) years. PEO and positive family history were the two prominent features of these patients, and ataxia, neuropathy, and hypogonadism were also present as onset symptoms in some patients. Fifteen of 20 probands with multiple mtDNA deletions were identified to carry nuclear gene variants; eight (40.0%) probands had variants within POLG, two (10.0%) within TWNK, two (10.0%) within RRM2B, two (10.0%) within TK2, and one (5.0%) within POLG2. A total of 24 variants were found in these five nuclear genes, of which 19 were novel. The causal nuclear genetic factors in five pedigrees remain undetermined. Conclusions The POLG gene is the most common disease‐causing gene in this group of PEO patients with multiple mtDNA deletions. While inherited PEO is the most prominent symptoms in these patients, genotypic and phenotypic heterogeneity still exist, for example in onset age, initial symptoms, and accompanying manifestations.
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Affiliation(s)
- Yue Hou
- Department of Neurology, Peking University First Hospital, Beijing, China.,Department of Geriatrics, Peking University First Hospital, Beijing, China
| | - Xutong Zhao
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhiying Xie
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Meng Yu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - He Lv
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
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11
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Romero-Morales AI, Gama V. Revealing the Impact of Mitochondrial Fitness During Early Neural Development Using Human Brain Organoids. Front Mol Neurosci 2022; 15:840265. [PMID: 35571368 PMCID: PMC9102998 DOI: 10.3389/fnmol.2022.840265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial homeostasis -including function, morphology, and inter-organelle communication- provides guidance to the intrinsic developmental programs of corticogenesis, while also being responsive to environmental and intercellular signals. Two- and three-dimensional platforms have become useful tools to interrogate the capacity of cells to generate neuronal and glia progeny in a background of metabolic dysregulation, but the mechanistic underpinnings underlying the role of mitochondria during human neurogenesis remain unexplored. Here we provide a concise overview of cortical development and the use of pluripotent stem cell models that have contributed to our understanding of mitochondrial and metabolic regulation of early human brain development. We finally discuss the effects of mitochondrial fitness dysregulation seen under stress conditions such as metabolic dysregulation, absence of developmental apoptosis, and hypoxia; and the avenues of research that can be explored with the use of brain organoids.
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Affiliation(s)
| | - Vivian Gama
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, United States
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
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12
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Clinical and genetic analysis of combined oxidative phosphorylation defificiency-10 caused by MTO1 mutation. Clin Chim Acta 2022; 526:74-80. [PMID: 34990597 DOI: 10.1016/j.cca.2021.12.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 12/26/2021] [Indexed: 01/02/2023]
Abstract
The mitochondrial translation optimization factor 1(MTO1) gene mutations had been reported to be linked to combined oxidative phosphorylation defificiency-10 (COXPD10). In this study, we presented the detailed clinical features and genetic analysis of the patient with two variants in MTO1, and reviewed 42 different cases available in publications. Whole exome sequencing and bioinformatics analysis were employed to detect the genetic variants of a 6-month-old boy with metabolic disorder and multiple organ failure; Sanger sequencing was performed to confirm the origin of variants; and clinical data of the patients was retrospectively collected and analyzed. Variant classification was followed to ACMG guidline. The proband was diagnosed with multiple organ failure, severe pneumonia, sepsis, hyperlactatemia, metabolic acidosis, and moderate anemia. Compound heterozygous mutations in the coding region of MTO1 gene (c.1291C>T/p.Arg431Trp and c.1390C>T/p.Arg464Cys) were identified, and the results of family verification experiment showed that the mutations were inherited from the parents, respectively. Combined with clinical symptoms, the patient was diagnosed as COXPD10. In summary, hallmark features of MTO1 mutations were lactic acidosis and hypertrophic cardiomyopathy. Of note, patients with the same genetic mutation may not have the same clinical presentation. Additional MTO1 defificiency cases will help to make genotype-phenotype correlations clearer.
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13
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Two Cases of Leigh Syndrome in One Family: Diagnostic Challenges and Clinical Management Experience in Latvia. Case Rep Med 2021; 2021:5266820. [PMID: 34868319 PMCID: PMC8641989 DOI: 10.1155/2021/5266820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/12/2021] [Indexed: 11/17/2022] Open
Abstract
Leigh syndrome is a neurodegenerative disorder with an incidence of 1 : 40,000 live births. The clinical presentation of LS is highly variable with heterogeneity in the disease-associated symptoms of cerebellar, motor, and extrapyramidal dysfunction and common infections. There is no effective treatment for this condition; as such, the prognosis of this condition is very poor with death occurring within the first few years of life. In this study, we report the first LS case in Latvia with SURF1 pathogenic variants in two siblings. The difficulties encountered establishing a diagnosis for the first proband and the effective prenatal diagnosis for the second offspring that led to termination of the pregnancy are discussed.
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14
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Kuthethur R, Prasad K, Chakrabarty S, Kabekkodu SP, Singh KK, Thangaraj K, Satyamoorthy K. Advances in mitochondrial medicine and translational research. Mitochondrion 2021; 61:62-68. [PMID: 34363984 DOI: 10.1016/j.mito.2021.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 10/20/2022]
Abstract
Current knowledge of mitochondrial biology and function has provided tools and technologies that helped a better understanding of the molecular etiology of complex mitochondrial disorders. Dual genetic control of this subcellular organelle function regulates various signaling mechanisms which are essential for metabolism, bioenergetics, fatty acid biosynthesis, and DNA replication & repair. Understanding nuclear mitochondrial crosstalk through advanced genomics as well as clinical perspectives is the overall basis of mitochondrial research and medicine, also the sole objective of Society for Mitochondrial Medicine and Research (SMRM) - India. The eighth virtual international conference on 'Advances in Mitochondrial Medicine and Translational Research' was organized at the Manipal School of Life Sciences, MAHE, Manipal, India, during 6 - 7 November 2020. The aim of the virtual conference was to highlight the recent advances and future perspectives that represent comprehensive clinical and fundamental research interests in the area of mitochondrial biology of human diseases. To systematically present the various findings in mitochondrial biology, the meeting was themed with specific aspects comprising (a) mitochondrial disorders: clinical & genomic perspectives, (b) mitochondria in cancer, (c) mitochondrial metabolism & disorders, and (d) mitochondrial diseases & therapy. This report provides an overview of the recent advancements in the area of mitochondrial biology and medicine that was discussed at the conference.
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Affiliation(s)
- Raviprasad Kuthethur
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Keshava Prasad
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Shama Prasada Kabekkodu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Keshav K Singh
- Department of Genetics, School of Medicine, The University of Alabama at Birmingham, Kaul Genetics Building, Rm. 620, 720 20th St. South, Birmingham, AL, 35294, United States
| | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India; Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500 039, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India.
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15
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Kuthethur R, Prasad K, Chakrabarty S, Prasada Kabekkodu S, Singh KK, Thangaraj K, Satyamoorthy K. Advances in Mitochondrial Medicine and Translational Research. Mitochondrion 2021:S1567-7249(21)00102-1. [PMID: 34363984 DOI: 10.1016/j.mito.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Current knowledge of mitochondrial biology and function has provided with tools and technologies that helped a better understanding of the molecular etiology of complex mitochondrial disorders. Dual genetic control of this subcellular organelle function regulates various signaling mechanisms which are essential for metabolism, bioenergetics, fatty acid biosynthesis, and DNA replication & repair. Understanding nuclear mitochondrial crosstalk through advanced genomics as well as clinical perspectives is the overall basis of mitochondrial research and medicine, also the sole objective of Society for Mitochondrial Medicine and Research (SMRM) - India. The eighth virtual international conference on 'Advances in Mitochondrial Medicine and Translational Research' was organized at the Manipal School of Life Sciences, MAHE, Manipal, India, during 6 - 7 November 2020. The aim of the virtual conference was to highlight the recent advances and future perspectives that represent comprehensive clinical and fundamental research interests in the area of mitochondrial biology of human diseases. To systematically present the various findings in mitochondrial biology, the meeting was themed with specific aspects comprising (a) mitochondrial disorders: clinical & genomic perspectives, (b) mitochondria in cancer, (c) mitochondrial metabolism & disorders, and (d) mitochondrial diseases & therapy. This report provides an overview of the recent advancements in the area of mitochondrial biology and medicine that was discussed at the conference.
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Affiliation(s)
- Raviprasad Kuthethur
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Keshava Prasad
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Shama Prasada Kabekkodu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India
| | - Keshav K Singh
- Department of Genetics, School of Medicine, The University of Alabama at Birmingham, Kaul Genetics Building, Rm. 620, 720 20th St. South, Birmingham, AL 35294, USA
| | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India; Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500 039, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, India.
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16
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Tinker RJ, Lim AZ, Stefanetti RJ, McFarland R. Current and Emerging Clinical Treatment in Mitochondrial Disease. Mol Diagn Ther 2021; 25:181-206. [PMID: 33646563 PMCID: PMC7919238 DOI: 10.1007/s40291-020-00510-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/27/2020] [Indexed: 12/11/2022]
Abstract
Primary mitochondrial disease (PMD) is a group of complex genetic disorders that arise due to pathogenic variants in nuclear or mitochondrial genomes. Although PMD is one of the most prevalent inborn errors of metabolism, it often exhibits marked phenotypic variation and can therefore be difficult to recognise. Current treatment for PMD revolves around supportive and preventive approaches, with few disease-specific therapies available. However, over the last decade there has been considerable progress in our understanding of both the genetics and pathophysiology of PMD. This has resulted in the development of a plethora of new pharmacological and non-pharmacological therapies at varying stages of development. Many of these therapies are currently undergoing clinical trials. This review summarises the latest emerging therapies that may become mainstream treatment in the coming years. It is distinct from other recent reviews in the field by comprehensively addressing both pharmacological non-pharmacological therapy from both a bench and a bedside perspective. We highlight the current and developing therapeutic landscape in novel pharmacological treatment, dietary supplementation, exercise training, device use, mitochondrial donation, tissue replacement gene therapy, hypoxic therapy and mitochondrial base editing.
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Affiliation(s)
- Rory J Tinker
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Albert Z Lim
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Renae J Stefanetti
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
- NHS Highly Specialised Service for Rare Mitochondrial Disorders for Adults and Children, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
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17
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Akiyama N, Shimura M, Yamazaki T, Harashima H, Fushimi T, Tsuruoka T, Ebihara T, Ichimoto K, Matsunaga A, Saito-Tsuruoka M, Yatsuka Y, Kishita Y, Kohda M, Namba A, Kamei Y, Okazaki Y, Kosugi S, Ohtake A, Murayama K. Prenatal diagnosis of severe mitochondrial diseases caused by nuclear gene defects: a study in Japan. Sci Rep 2021; 11:3531. [PMID: 33574353 PMCID: PMC7878886 DOI: 10.1038/s41598-021-81015-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/28/2020] [Indexed: 12/05/2022] Open
Abstract
Prenatal diagnoses of mitochondrial diseases caused by defects in nuclear DNA (nDNA) or mitochondrial DNA have been reported in several countries except for Japan. The present study aimed to clarify the status of prenatal genetic diagnosis of mitochondrial diseases caused by nDNA defects in Japan. A comprehensive genomic analysis was performed to diagnose more than 400 patients, of which, 13 families (16 cases) had requested prenatal diagnoses. Eight cases diagnosed with wild type homozygous or heterozygous variants same as either of the heterozygous parents continued the pregnancy and delivered healthy babies. Another eight cases were diagnosed with homozygous, compound heterozygous, or hemizygous variants same as the proband. Of these, seven families chose to terminate the pregnancy, while one decided to continue the pregnancy. Neonatal- or infantile-onset mitochondrial diseases show severe phenotypes and lead to lethality. Therefore, such diseases could be candidates for prenatal diagnosis with careful genetic counseling, and prenatal testing could be a viable option for families.
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Affiliation(s)
- Nana Akiyama
- Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan.,Department of Medical Genetics/Medical Ethics, Kyoto University School of Public Health, Kyoto, Japan
| | - Masaru Shimura
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Taro Yamazaki
- Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Hiroko Harashima
- Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Takuya Fushimi
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Tomoko Tsuruoka
- Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Tomohiro Ebihara
- Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Keiko Ichimoto
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Ayako Matsunaga
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Megumi Saito-Tsuruoka
- Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Yukiko Yatsuka
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Department of Life Science, Faculty of Science and Engineering, Kindai University, Osaka, Japan
| | - Masakazu Kohda
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Akira Namba
- Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan.,Department of Obstetrics and Gynecology, Saitama Medical University Hospital, Saitama, Japan
| | - Yoshimasa Kamei
- Department of Obstetrics and Gynecology, Saitama Medical University Hospital, Saitama, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Shinji Kosugi
- Department of Medical Genetics/Medical Ethics, Kyoto University School of Public Health, Kyoto, Japan
| | - Akira Ohtake
- Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan. .,Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan. .,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan.
| | - Kei Murayama
- Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan. .,Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan. .,Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.
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18
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Steffann J, Monnot S, Magen M, Assouline Z, Gigarel N, Ville Y, Salomon L, Bessiere B, Martinovic J, Rötig A, Bengoa J, Borghèse R, Munnich A, Barcia G, Bonnefont JP. A retrospective study on the efficacy of prenatal diagnosis for pregnancies at risk of mitochondrial DNA disorders. Genet Med 2020; 23:720-731. [PMID: 33303968 DOI: 10.1038/s41436-020-01043-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 11/11/2020] [Accepted: 11/11/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Prenatal diagnosis of mitochondrial DNA (mtDNA) disorders is challenging due to potential instability of fetal mutant loads and paucity of data connecting prenatal mutant loads to postnatal observations. Retrospective study of our prenatal cohort aims to examine the efficacy of prenatal diagnosis to improve counseling and reproductive options for those with pregnancies at risk of mtDNA disorders. METHODS We report on a retrospective review of 20 years of prenatal diagnosis of pathogenic mtDNA variants in 80 pregnant women and 120 fetuses. RESULTS Patients with undetectable pathogenic variants (n = 29) consistently had fetuses free of variants, while heteroplasmic women (n = 51) were very likely to transmit their variant (57/78 fetuses, 73%). In the latter case, 26 pregnancies were terminated because fetal mutant loads were >40%. Of the 84 children born, 27 were heteroplasmic (mutant load <65%). To date, no medical problems related to mitochondrial dysfunction have been reported. CONCLUSION Placental heterogeneity of mutant loads questioned the reliability of chorionic villous testing. Fetal mutant load stability, however, suggests the reliability of a single analysis of amniotic fluid at any stage of pregnancy for prenatal diagnosis of mtDNA disorders. Mutant loads under 40% reliably predict lack of symptoms in the progeny of heteroplasmic women.
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Affiliation(s)
- Julie Steffann
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France. .,Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France.
| | - Sophie Monnot
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Maryse Magen
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Zahra Assouline
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Nadine Gigarel
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Yves Ville
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service d'Obstétrique - Maternité, chirurgie médecine et imagerie fœtale, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Laurent Salomon
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service d'Obstétrique - Maternité, chirurgie médecine et imagerie fœtale, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Bettina Bessiere
- Service d'histo-embryologie et fœtopathologie, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Jelena Martinovic
- Unité de Foetopathologie, Hôpital Antoine Béclère, GHU Paris Saclay, AP-HP, Clamart, France
| | - Agnès Rötig
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France
| | - Joana Bengoa
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Roxana Borghèse
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Arnold Munnich
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Giulia Barcia
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Jean-Paul Bonnefont
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
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19
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Montano V, Gruosso F, Simoncini C, Siciliano G, Mancuso M. Clinical features of mtDNA-related syndromes in adulthood. Arch Biochem Biophys 2020; 697:108689. [PMID: 33227288 DOI: 10.1016/j.abb.2020.108689] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/06/2020] [Accepted: 11/15/2020] [Indexed: 01/26/2023]
Abstract
Mitochondrial diseases are the most common inheritable metabolic diseases, due to defects in oxidative phosphorylation. They are caused by mutations of nuclear or mitochondrial DNA in genes involved in mitochondrial function. The peculiarity of "mitochondrial DNA genetics rules" in part explains the marked phenotypic variability, the complexity of genotype-phenotype correlations and the challenge of genetic counseling. The new massive genetic sequencing technologies have changed the diagnostic approach, enhancing mitochondrial DNA-related syndromes diagnosis and often avoiding the need of a tissue biopsy. Here we present the most common phenotypes associated with a mitochondrial DNA mutation with the recent advances in diagnosis and in therapeutic perspectives.
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Affiliation(s)
- V Montano
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - F Gruosso
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - C Simoncini
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - G Siciliano
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - M Mancuso
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy.
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20
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Naeem MM, Maheshan R, Costford SR, Wahedi A, Trajkovski M, Plavec J, Yatsunyk LA, Ciesielski GL, Kaufman BA, Sondheimer N. G-quadruplex-mediated reduction of a pathogenic mitochondrial heteroplasmy. Hum Mol Genet 2020; 28:3163-3174. [PMID: 31261379 DOI: 10.1093/hmg/ddz153] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/28/2019] [Accepted: 06/21/2019] [Indexed: 12/18/2022] Open
Abstract
Disease-associated variants in mitochondrial DNA (mtDNA) are frequently heteroplasmic, a state of co-existence with the wild-type genome. Because heteroplasmy correlates with the severity and penetrance of disease, improvement in the ratio between these genomes in favor of the wild-type, known as heteroplasmy shifting, is potentially therapeutic. We evaluated known pathogenic mtDNA variants and identified those with the potential for allele-specific differences in the formation of non-Watson-Crick G-quadruplex (GQ) structures. We found that the Leigh syndrome (LS)-associated m.10191C variant promotes GQ formation within local sequence in vitro. Interaction of this sequence with a small molecule GQ-binding agent, berberine hydrochloride, further increased GQ stability. The GQ formed at m.10191C differentially impeded the processivity of the mitochondrial DNA polymerase gamma (Pol γ) in vitro, providing a potential means to favor replication of the wild-type allele. We tested the potential for shifting heteroplasmy through the cyclical application of two different mitochondria-targeted GQ binding compounds in primary fibroblasts from patients with m.10191T>C heteroplasmy. Treatment induced alternating mtDNA depletion and repopulation and was effective in shifting heteroplasmy towards the non-pathogenic allele. Similar treatment of pathogenic heteroplasmies that do not affect GQ formation did not induce heteroplasmy shift. Following treatment, heteroplasmic m.10191T>C cells had persistent improvements and heteroplasmy and a corresponding increase in maximal mitochondrial oxygen consumption. This study demonstrates the potential for using small-molecule GQ-binding agents to induce genetic and functional improvements in m.10191T>C heteroplasmy.
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Affiliation(s)
| | - Rathena Maheshan
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Sheila R Costford
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Azizia Wahedi
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Marko Trajkovski
- National Institute of Chemistry, Slovenian NMR Center, Ljubljana, Slovenia
| | - Janez Plavec
- National Institute of Chemistry, Slovenian NMR Center, Ljubljana, Slovenia
| | - Liliya A Yatsunyk
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore PA, USA
| | | | - Brett A Kaufman
- Center for Metabolism and Mitochondrial Medicine, Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Neal Sondheimer
- Institute of Medical Science.,Departments of Paediatrics and Molecular Genetics, The University of Toronto, Toronto, ON, Canada.,Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
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Schubert Baldo M, Vilarinho L. Molecular basis of Leigh syndrome: a current look. Orphanet J Rare Dis 2020; 15:31. [PMID: 31996241 PMCID: PMC6990539 DOI: 10.1186/s13023-020-1297-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/05/2020] [Indexed: 01/15/2023] Open
Abstract
Leigh Syndrome (OMIM 256000) is a heterogeneous neurologic disorder due to damage in mitochondrial energy production that usually starts in early childhood. The first description given by Leigh pointed out neurological symptoms in children under 2 years and premature death. Following cases brought some hypothesis to explain the cause due to similarity to other neurological diseases and led to further investigation for metabolic diseases. Biochemical evaluation and specific metabolic profile suggested impairment in energy production (OXPHOS) in mitochondria. As direct approach to involved tissues is not always possible or safe, molecular analysis is a great cost-effective option and, besides biochemical results, is required to confirm the underlying cause of this syndrome face to clinical suspicion. The Next Generation Sequencing (NGS) advance represented a breakthrough in molecular biology allowing simultaneous gene analysis giving short-time results and increasing the variants underlying this syndrome, counting over 75 monogenic causes related so far. NGS provided confirmation of emerging cases and brought up diagnosis in atypical presentations as late-onset cases, which turned Leigh into a heterogeneous syndrome with variable outcomes. This review highlights clinical presentation in both classic and atypical phenotypes, the investigation pathway throughout confirmation emphasizing the underlying genetic heterogeneity and increasing number of genes assigned to this syndrome as well as available treatment.
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Affiliation(s)
- Manuela Schubert Baldo
- Newborn screening, metabolism and genetics unit - human genetics department, Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA), Porto, Portugal.
| | - Laura Vilarinho
- Newborn screening, metabolism and genetics unit - human genetics department, Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA), Porto, Portugal
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22
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Unim B, Pitini E, Lagerberg T, Adamo G, De Vito C, Marzuillo C, Villari P. Current Genetic Service Delivery Models for the Provision of Genetic Testing in Europe: A Systematic Review of the Literature. Front Genet 2019; 10:552. [PMID: 31275354 PMCID: PMC6593087 DOI: 10.3389/fgene.2019.00552] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/24/2019] [Indexed: 11/13/2022] Open
Abstract
Background: The provision of genetic services, along with research in the fields of genomics and genetics, has evolved in recent years to meet the increasing demand of consumers interested in prediction of genetic diseases and various inherited traits. The aim of this study is to evaluate genetic services in order to identify and classify delivery models for the provision of genetic testing in European and in extra-European countries. Methods: A systematic review of the literature was conducted using five electronic resources. Inclusion criteria were that studies be published in English or Italian during the period 2000-2015 and carried out in European or extra-European countries (Canada, USA, Australia, or New Zealand). Results: 148 genetic programs were identified in 117 articles and were delivered mostly in the UK (59, 40%), USA (35, 24%) or Australia (16, 11%). The programs were available nationally (66; 45%), regionally (49; 33%) or in urban areas (21, 14%). Ninety-six (64%) of the programs were integrated into healthcare systems, 48 (32.21%) were pilot programs and five (3%) were direct-to-consumer genetic services. The genetic tests offered were mainly for BRCA1/2 (59, 40%), Lynch syndrome (23, 16%), and newborn screening (18, 12%). Healthcare professionals with different backgrounds are increasingly engaged in the provision of genetic services. Based on which healthcare professionals have prominent roles in the respective patient care pathways, genetic programs were classified into five models: (i) the geneticists model; (ii) the primary care model; (iii) the medical specialist model; (iv) the population screening programs model; and (v) the direct-to-consumer model. Conclusions: New models of genetic service delivery are currently under development worldwide to address the increasing demand for accessible and affordable services. These models require the integration of genetics into all medical specialties, collaboration among different healthcare professionals, and the redistribution of professional roles. An appropriate model for genetic service provision in a specific setting should ideally be defined according to the type of healthcare system, the genetic test provided within a genetic program, and the cost-effectiveness of the intervention. Only applications with proven efficacy and cost-effectiveness should be implemented in healthcare systems and made available to all citizens.
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Affiliation(s)
- Brigid Unim
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Erica Pitini
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | | | - Giovanna Adamo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Corrado De Vito
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Carolina Marzuillo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Paolo Villari
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
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23
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Ibrahim AH, Rahman NNA, Saifuddeen SM, Baharuddin M. Tri-parent Baby Technology and Preservation of Lineage: An Analysis from the Perspective of Maqasid al-Shari'ah Based Islamic Bioethics. SCIENCE AND ENGINEERING ETHICS 2019; 25:129-142. [PMID: 29071572 DOI: 10.1007/s11948-017-9980-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/19/2017] [Indexed: 06/07/2023]
Abstract
Tri-parent baby technology is an assisted reproductive treatment which aims to minimize or eliminate maternal inheritance of mutated mitochondrial DNA (mtDNA). The technology became popular following the move by the United Kingdom in granting license to a group of researchers from the Newcastle Fertility Centre, Newcastle University to conduct research on the symptoms of defective mtDNA. This technology differs from other assisted reproductive technology because it involves the use of gamete components retrieved from three different individuals. Indirectly, it affects the preservation of lineage which is important from an Islamic point of view. This paper aims to analyze and discuss the implications of the tri-parent technology on preservation of lineage from the perspective of Maqasid al-Shari'ah based the Islamic bioethics. The analysis shows that there are a few violations of the preservation of lineage, hence the tri-parent baby technology should not be permitted.
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Affiliation(s)
- Abdul Halim Ibrahim
- Programme of Applied Science with Islamic Studies, Academy of Islamic Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Noor Naemah Abdul Rahman
- Department of Fiqh and Usul, Academy of Islamic Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Shaikh Mohd Saifuddeen
- Programme of Applied Science with Islamic Studies, Academy of Islamic Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia
- Centre for Science and Environment Studies, Institute of Islamic Understanding Malaysia, 2 Langgak Tunku Off Jalan Tuanku Abdul Halim, 50480, Kuala Lumpur, Malaysia
| | - Madiha Baharuddin
- Programme of Applied Science with Islamic Studies, Academy of Islamic Studies, University of Malaya, 50603, Kuala Lumpur, Malaysia
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24
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Recent topics: the diagnosis, molecular genesis, and treatment of mitochondrial diseases. J Hum Genet 2018; 64:113-125. [PMID: 30459337 DOI: 10.1038/s10038-018-0528-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 12/30/2022]
Abstract
Mitochondrial diseases are inherited metabolic diseases based on disorders of energy production. The expansion of exome analyses has led to the discovery of many pathogenic nuclear genes associated with these diseases, and research into the pathogenesis of metabolic diseases has progressed. In cases of Leigh syndrome, it is desirable to perform both biochemical and genetic analyses, and pathogenic gene mutations have been identified in over half of the cases analyzed this way. Tandem mass screening and organic acid analyses of urine can sometimes provide important information that leads to the identification of pathogenic genes. Our comprehensive gene analyses have led to the discovery of several novel genes for mitochondrial diseases. Indeed, we reported that GTPBP3 and QRSL1 are involved in mitochondrial DNA maturation. In 2017, as a result of international collaboration, we also identified that mutations in ATAD3 and C1QBP cause mitochondrial disease. Given the varied pathogeneses, treatments for mitochondrial diseases should be specifically tailored to the mutated gene. Clinical trials of sodium pyruvate, 5-aminolevulinic acid with sodium ferrous citrate, and taurine as a treatment for mitochondrial disease have begun in Japan. Given that some mitochondrial diseases may respond well to certain treatments if the pathogenic gene can be identified, an early genetic diagnosis is crucial. Additionally, in Japan, prenatal diagnoses for mitochondrial diseases caused by nuclear genes have been achieved for genes shown to be pathogenic. Treatment and management approaches, including prenatal diagnoses, specifically tailored to the various phenotypes and pathologies of mitochondrial diseases are expected to become increasingly available.
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25
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Abstract
Mitochondrial myopathies are progressive muscle conditions caused primarily by the impairment of oxidative phosphorylation (OXPHOS) in the mitochondria. This causes a deficit in energy production in the form of adenosine triphosphate (ATP), particularly in skeletal muscle. The diagnosis of mitochondrial myopathy is reliant on the combination of numerous techniques including traditional histochemical, immunohistochemical, and biochemical testing combined with the fast-emerging molecular genetic techniques, namely next-generation sequencing (NGS). This has allowed for the diagnosis to become more effective in terms of determining causative or novel genes. However, there are currently no effective or disease-modifying treatments available for the vast majority of patients with mitochondrial myopathies. Existing therapeutic options focus on the symptomatic management of disease manifestations. An increasing number of clinical trials have investigated the therapeutic effects of various vitamins, cofactors, and small molecules, though these trials have failed to show definitive outcome measures for clinical practice thus far. In addition, new molecular strategies, specifically mtZFNs and mtTALENs, that cause beneficial heteroplasmic shifts in cell lines harboring varying pathogenic mtDNA mutations offer hope for the future. Moreover, recent developments in the reproductive options for patients with mitochondrial myopathies mean that for some families, the possibility of preventing transmission of the mutation to the next generation is now possible.
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Affiliation(s)
- Syeda T Ahmed
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Lyndsey Craven
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Oliver M Russell
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
- MRC Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
| | - Amy E Vincent
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
- MRC Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK.
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26
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Advances in methods for reducing mitochondrial DNA disease by replacing or manipulating the mitochondrial genome. Essays Biochem 2018; 62:455-465. [PMID: 29950320 PMCID: PMC6056713 DOI: 10.1042/ebc20170113] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/23/2018] [Accepted: 05/03/2018] [Indexed: 11/25/2022]
Abstract
Mitochondrial DNA (mtDNA) is a multi-copy genome whose cell copy number varies depending on tissue type. Mutations in mtDNA can cause a wide spectrum of diseases. Mutated mtDNA is often found as a subset of the total mtDNA population in a cell or tissue, a situation known as heteroplasmy. As mitochondrial dysfunction only presents after a certain level of heteroplasmy has been acquired, ways to artificially reduce or replace the mutated species have been attempted. This review addresses recent approaches and advances in this field, focusing on the prevention of pathogenic mtDNA transfer via mitochondrial donation techniques such as maternal spindle transfer and pronuclear transfer in which mutated mtDNA in the oocyte or fertilized embryo is substituted with normal copies of the mitochondrial genome. This review also discusses the molecular targeting and cleavage of pathogenic mtDNA to shift heteroplasmy using antigenomic therapy and genome engineering techniques including Zinc-finger nucleases and transcription activator-like effector nucleases. Finally, it considers CRISPR technology and the unique difficulties that mitochondrial genome editing presents.
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27
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Aravintha Siva M, Mahalakshmi R, Bhakta-Guha D, Guha G. Gene therapy for the mitochondrial genome: Purging mutations, pacifying ailments. Mitochondrion 2018; 46:195-208. [PMID: 29890303 DOI: 10.1016/j.mito.2018.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
In the recent years, the reported cases of mitochondrial disorders have reached a colossal number. These disorders spawn a sundry of pathological conditions, which lead to pernicious symptoms and even fatality. Due to the unpredictable etiologies, mitochondrial diseases are putatively referred to as "mystondria" (mysterious diseases of mitochondria). Although present-day research has greatly improved our understanding of mitochondrial disorders, effective therapeutic interventions are still at the precursory stage. The conundrum becomes further complicated because these pathologies might occur due to either mitochondrial DNA (mtDNA) mutations or due to mutations in the nuclear DNA (nDNA), or both. While correcting nDNA mutations by using gene therapy (replacement of defective genes by delivering wild-type (WT) ones into the host cell, or silencing a dominant mutant allele that is pathogenic) has emerged as a promising strategy to address some mitochondrial diseases, the complications in correcting the defects of mtDNA in order to renovate mitochondrial functions have remained a steep challenge. In this review, we focus specifically on the selective gene therapy strategies that have demonstrated prospects in targeting the pathological mutations in the mitochondrial genome, thereby treating mitochondrial ailments.
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Affiliation(s)
- M Aravintha Siva
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - R Mahalakshmi
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - Dipita Bhakta-Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
| | - Gunjan Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
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28
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Poulton J, Finsterer J, Yu-Wai-Man P. Genetic Counselling for Maternally Inherited Mitochondrial Disorders. Mol Diagn Ther 2018; 21:419-429. [PMID: 28536827 DOI: 10.1007/s40291-017-0279-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of this review was to provide an evidence-based approach to frequently asked questions relating to the risk of transmitting a maternally inherited mitochondrial disorder (MID). We do not address disorders linked with disturbed mitochondrial DNA (mtDNA) maintenance, causing mtDNA depletion or multiple mtDNA deletions, as these are autosomally inherited. The review addresses questions regarding prognosis, recurrence risks and the strategies available to prevent disease transmission. The clinical and genetic complexity of maternally inherited MIDs represent a major challenge for patients, their relatives and health professionals. Since many of the genetic and pathophysiological aspects of MIDs remain unknown, counselling of affected patients and at-risk family members remains difficult. MtDNA mutations are maternally transmitted or, more rarely, they are sporadic, occurring de novo (~25%). Females carrying homoplasmic mtDNA mutations will transmit the mutant species to all of their offspring, who may or may not exhibit a similar phenotype depending on modifying, secondary factors. Females carrying heteroplasmic mtDNA mutations will transmit a variable amount of mutant mtDNA to their offspring, which can result in considerable phenotypic heterogeneity among siblings. The majority of mtDNA rearrangements, such as single large-scale deletions, are sporadic, but there is a small risk of recurrence (~4%) among the offspring of affected women. The range and suitability of reproductive choices for prospective mothers is a complex area of mitochondrial medicine that needs to be managed by experienced healthcare professionals as part of a multidisciplinary team. Genetic counselling is facilitated by the identification of the underlying causative genetic defect. To provide more precise genetic counselling, further research is needed to clarify the secondary factors that account for the variable penetrance and the often marked differential expressivity of pathogenic mtDNA mutations both within and between families.
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Affiliation(s)
- Joanna Poulton
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford, UK
| | - Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180, Vienna, Austria.
| | - Patrick Yu-Wai-Man
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.,NIHR Biomedical Research Centre, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK.,Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
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29
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Complete elimination of a pathogenic homoplasmic mtDNA mutation in one generation. Mitochondrion 2018; 45:18-21. [PMID: 29408632 DOI: 10.1016/j.mito.2018.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/17/2018] [Accepted: 01/26/2018] [Indexed: 01/23/2023]
Abstract
Mitochondrial DNA (mtDNA) mutations have been implicated in a wide variety of neurological conditions and are maternally inherited through a complex process which is not fully understood. Genetic counselling for mitochondrial conditions secondary to a mtDNA mutation can be challenging as it is not currently possible to accurately predict the mutational load/heteroplasmy of the mutation which could be passed to the offspring. In general, one expects that the higher the level of heteroplasmy the more likely that the same mtDNA mutation will be seen in the offspring. We report here a family which places a caveat on genetic counselling for mtDNA disorders. The proband is a 63 year old woman with m.14459G>A associated dystonia/spasticity/ataxia. The m.14459G>A mutation was detected at homoplasmic/near homoplasmic levels in her muscle tissue and fibroblasts, but did not appear to have been passed on to any of her offspring. To our knowledge, this is the first report of complete selection against a homoplasmic variant within maternally transmitted mtDNA. It is not clear if this novel phenomenon occurred by random chance or by another method of mitochondrial selection.
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30
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Craven L, Tang MX, Gorman GS, De Sutter P, Heindryckx B. Novel reproductive technologies to prevent mitochondrial disease. Hum Reprod Update 2018. [PMID: 28651360 DOI: 10.1093/humupd/dmx018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The use of nuclear transfer (NT) has been proposed as a novel reproductive treatment to overcome the transmission of maternally-inherited mitochondrial DNA (mtDNA) mutations. Pathogenic mutations in mtDNA can cause a wide-spectrum of life-limiting disorders, collectively known as mtDNA disease, for which there are currently few effective treatments and no known cures. The many unique features of mtDNA make genetic counselling challenging for women harbouring pathogenic mtDNA mutations but reproductive options that involve medical intervention are available that will minimize the risk of mtDNA disease in their offspring. This includes PGD, which is currently offered as a clinical treatment but will not be suitable for all. The potential for NT to reduce transmission of mtDNA mutations has been demonstrated in both animal and human models, and has recently been clinically applied not only to prevent mtDNA disease but also for some infertility cases. In this review, we will interrogate the different NT techniques, including a discussion on the available safety and efficacy data of these technologies for mtDNA disease prevention. In addition, we appraise the evidence for the translational use of NT technologies in infertility. OBJECTIVE AND RATIONALE We propose to review the current scientific evidence regarding the clinical use of NT to prevent mitochondrial disease. SEARCH METHODS The scientific literature was investigated by searching PubMed database until Jan 2017. Relevant documents from Human Fertilisation and Embryology Authority as well as reports from both the scientific and popular media were also implemented. The above searches were based on the following key words: 'mitochondria', 'mitochondrial DNA'; 'mitochondrial DNA disease', 'fertility'; 'preimplantation genetic diagnosis', 'nuclear transfer', 'mitochondrial replacement' and 'mitochondrial donation'. OUTCOMES While NT techniques have been shown to effectively reduce the transmission of heteroplasmic mtDNA variants in animal models, and increasing evidence supports their use to prevent the transmission of human mtDNA disease, the need for robust, long-term evaluation is still warranted. Moreover, prenatal screening would still be strongly advocated in combination with the use of these IVF-based technologies. Scientific evidence to support the use of NT and other novel reproductive techniques for infertility is currently lacking. WIDER IMPLICATIONS It is mandatory that any new ART treatments are first adequately assessed in both animal and human models before the cautious implementation of these new therapeutic approaches is clinically undertaken. There is growing evidence to suggest that the translation of these innovative technologies into clinical practice should be cautiously adopted only in highly selected patients. Indeed, given the limited safety and efficacy data, close monitoring of any offspring remains paramount.
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Affiliation(s)
- Lyndsey Craven
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Mao-Xing Tang
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Petra De Sutter
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Björn Heindryckx
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
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31
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Vachin P, Adda-Herzog E, Chalouhi G, Elie C, Rio M, Rondeau S, Gigarel N, Jabot Hanin F, Monnot S, Borghese R, Bengoa J, Ville Y, Rotig A, Munnich A, Bonnefont JP, Steffann J. Segregation of mitochondrial DNA mutations in the human placenta: implication for prenatal diagnosis of mtDNA disorders. J Med Genet 2017; 55:131-136. [DOI: 10.1136/jmedgenet-2017-104615] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/08/2017] [Accepted: 06/11/2017] [Indexed: 11/03/2022]
Abstract
BackgroundMitochondrial DNA (mtDNA) disorders have a high clinical variability, mainly explained by variation of the mutant load across tissues. The high recurrence risk of these serious diseases commonly results in requests from at-risk couples for prenatal diagnosis (PND), based on determination of the mutant load on a chorionic villous sample (CVS). Such procedures are hampered by the lack of data regarding mtDNA segregation in the placenta.The objectives of this report were to determine whether mutant loads (1) are homogeneously distributed across the whole placentas, (2) correlate with those in amniocytes and cord blood cells and (3) correlate with the mtDNA copy number.MethodsWe collected 11 whole placentas carrying various mtDNA mutations (m.3243A>G, m.8344A>G, m.8993T>G, m.9185T>C and m.10197G>A) and, when possible, corresponding amniotic fluid samples (AFSs) and cord blood samples. We measured mutant loads in multiple samples from each placenta (n= 6–37), amniocytes and cord blood cells, as well as total mtDNA content in placenta samples.ResultsLoad distribution was homogeneous at the sample level when average mutant load was low (<20%) or high (>80%) at the whole placenta level. By contrast, a marked heterogeneity was observed (up to 43%) in the intermediate range (20%–80%), the closer it was to 40%–50% the mutant load, the wider the distribution. Mutant loads were found to be similar in amniocytes and cord blood cells, at variance with placenta samples. mtDNA content correlated to mutant load in m.3243A>G placentas only.ConclusionThese data indicate that (1) mutant load determined from CVS has to be interpreted with caution for PND of some mtDNA disorders and should be associated with/substituted by a mutant load measurement on amniocytes; (2) the m.3243A>G mutation behaves differently from other mtDNA mutations with respect to the impact on mtDNA copy number, as previously shown in human preimplantation embryogenesis.
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32
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Sallevelt SCEH, Dreesen JCFM, Coonen E, Paulussen ADC, Hellebrekers DMEI, de Die-Smulders CEM, Smeets HJM, Lindsey P. Preimplantation genetic diagnosis for mitochondrial DNA mutations: analysis of one blastomere suffices. J Med Genet 2017; 54:693-697. [PMID: 28668821 DOI: 10.1136/jmedgenet-2017-104633] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/26/2017] [Accepted: 05/31/2017] [Indexed: 11/03/2022]
Abstract
BACKGROUND Preimplantation genetic diagnosis (PGD) is a reproductive strategy for mitochondrial DNA (mtDNA) mutation carriers, strongly reducing their risk of affected offspring. Embryos either without the mutation or with mutation load below the phenotypic threshold are transferred to the uterus. Because of incidental heteroplasmy deviations in single blastomere and the relatively limited data available, we so far preferred relying on two blastomeres rather than one. Considering the negative effect of a two-blastomere biopsy protocol compared with a single-blastomere biopsy protocol on live birth delivery rate, we re-evaluated the error rate in our current dataset. METHODS For the m.3243A>G mutation, sufficient embryos/blastomeres were available for a powerful analysis. The diagnostic error rate, defined as a potential false-negative result, based on a threshold of 15%, was determined in 294 single blastomeres analysed in 73 embryos of 9 female m.3243A>G mutation carriers. RESULTS Only one out of 294 single blastomeres (0.34%) would have resulted in a false-negative diagnosis. False-positive diagnoses were not detected. CONCLUSION Our findings support a single-blastomere biopsy PGD protocol for the m.3243A>G mutation as the diagnostic error rate is very low. As in the early preimplantation embryo no mtDNA replication seems to occur and the mtDNA is divided randomly among the daughter cells, we conclude this result to be independent of the specific mutation and therefore applicable to all mtDNA mutations.
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Affiliation(s)
- Suzanne C E H Sallevelt
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands
| | - Joseph C F M Dreesen
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.,Research School for Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Edith Coonen
- Department of Obstetrics and Gynaecology, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands
| | - Aimee D C Paulussen
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.,Research School for Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Debby M E I Hellebrekers
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands
| | - Christine E M de Die-Smulders
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.,Research School for Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Hubert J M Smeets
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.,Research School for Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Maastricht University, Maastricht, The Netherlands
| | - Patrick Lindsey
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Maastricht University, Maastricht, The Netherlands
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Abstract
Mitochondrial disease is a challenging area of genetics because two distinct genomes can contribute to disease pathogenesis. It is also challenging clinically because of the myriad of different symptoms and, until recently, a lack of a genetic diagnosis in many patients. The last five years has brought remarkable progress in this area. We provide a brief overview of mitochondrial origin, function, and biology, which are key to understanding the genetic basis of mitochondrial disease. However, the primary purpose of this review is to describe the recent advances related to the diagnosis, genetic basis, and prevention of mitochondrial disease, highlighting the newly described disease genes and the evolving methodologies aimed at preventing mitochondrial DNA disease transmission.
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Affiliation(s)
- Lyndsey Craven
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom;
| | - Charlotte L Alston
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom;
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom;
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom;
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Bianco B, Montagna E. The advances and new technologies for the study of mitochondrial diseases. EINSTEIN-SAO PAULO 2017; 14:291-3. [PMID: 27462900 PMCID: PMC4943364 DOI: 10.1590/s1679-45082016md3561] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/21/2015] [Indexed: 11/29/2022] Open
Abstract
Genetic mitochondrial disorders are responsible for the most common inborn errors of metabolism, caused by mutations in either nuclear genes or in mitochondrial DNA. This article presents the prokaryotic origin of the organelle and the relation between nuclear and mitochondrial genomes, as well as current evolutionary models for such mechanisms. It also addresses the structure of mitochondrial genes, their expression pattern, clinical features of gene defects, risk of transmission and current techniques to avoid these events in assisted human reproduction. Finally, it discusses the ethical implications of these possibilities.
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Affiliation(s)
- Bianca Bianco
- Faculdade de Medicina do ABC, Santo André, SP, Brazil
| | - Erik Montagna
- Faculdade de Medicina do ABC, Santo André, SP, Brazil
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35
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Alston CL, Rocha MC, Lax NZ, Turnbull DM, Taylor RW. The genetics and pathology of mitochondrial disease. J Pathol 2016; 241:236-250. [PMID: 27659608 PMCID: PMC5215404 DOI: 10.1002/path.4809] [Citation(s) in RCA: 263] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/15/2016] [Accepted: 09/16/2016] [Indexed: 12/30/2022]
Abstract
Mitochondria are double-membrane-bound organelles that are present in all nucleated eukaryotic cells and are responsible for the production of cellular energy in the form of ATP. Mitochondrial function is under dual genetic control - the 16.6-kb mitochondrial genome, with only 37 genes, and the nuclear genome, which encodes the remaining ∼1300 proteins of the mitoproteome. Mitochondrial dysfunction can arise because of defects in either mitochondrial DNA or nuclear mitochondrial genes, and can present in childhood or adulthood in association with vast clinical heterogeneity, with symptoms affecting a single organ or tissue, or multisystem involvement. There is no cure for mitochondrial disease for the vast majority of mitochondrial disease patients, and a genetic diagnosis is therefore crucial for genetic counselling and recurrence risk calculation, and can impact on the clinical management of affected patients. Next-generation sequencing strategies are proving pivotal in the discovery of new disease genes and the diagnosis of clinically affected patients; mutations in >250 genes have now been shown to cause mitochondrial disease, and the biochemical, histochemical, immunocytochemical and neuropathological characterization of these patients has led to improved diagnostic testing strategies and novel diagnostic techniques. This review focuses on the current genetic landscape associated with mitochondrial disease, before focusing on advances in studying associated mitochondrial pathology in two, clinically relevant organs - skeletal muscle and brain. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Charlotte L Alston
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Mariana C Rocha
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Nichola Z Lax
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
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36
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Sallevelt SCEH, de Die-Smulders CEM, Hendrickx ATM, Hellebrekers DMEI, de Coo IFM, Alston CL, Knowles C, Taylor RW, McFarland R, Smeets HJM. De novo mtDNA point mutations are common and have a low recurrence risk. J Med Genet 2016; 54:73-83. [PMID: 27450679 PMCID: PMC5502310 DOI: 10.1136/jmedgenet-2016-103876] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/02/2016] [Accepted: 06/09/2016] [Indexed: 12/25/2022]
Abstract
Background Severe, disease-causing germline mitochondrial (mt)DNA mutations are maternally inherited or arise de novo. Strategies to prevent transmission are generally available, but depend on recurrence risks, ranging from high/unpredictable for many familial mtDNA point mutations to very low for sporadic, large-scale single mtDNA deletions. Comprehensive data are lacking for de novo mtDNA point mutations, often leading to misconceptions and incorrect counselling regarding recurrence risk and reproductive options. We aim to study the relevance and recurrence risk of apparently de novo mtDNA point mutations. Methods Systematic study of prenatal diagnosis (PND) and recurrence of mtDNA point mutations in families with de novo cases, including new and published data. ‘De novo’ based on the absence of the mutation in multiple (postmitotic) maternal tissues is preferred, but mutations absent in maternal blood only were also included. Results In our series of 105 index patients (33 children and 72 adults) with (likely) pathogenic mtDNA point mutations, the de novo frequency was 24.6%, the majority being paediatric. PND was performed in subsequent pregnancies of mothers of four de novo cases. A fifth mother opted for preimplantation genetic diagnosis because of a coexisting Mendelian genetic disorder. The mtDNA mutation was absent in all four prenatal samples and all 11 oocytes/embryos tested. A literature survey revealed 137 de novo cases, but PND was only performed for 9 (including 1 unpublished) mothers. In one, recurrence occurred in two subsequent pregnancies, presumably due to germline mosaicism. Conclusions De novo mtDNA point mutations are a common cause of mtDNA disease. Recurrence risk is low. This is relevant for genetic counselling, particularly for reproductive options. PND can be offered for reassurance.
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Affiliation(s)
- Suzanne C E H Sallevelt
- Department of Clinical Genetics, Maastricht University Medical Centre (MUMC), Maastricht, The Netherlands
| | - Christine E M de Die-Smulders
- Department of Clinical Genetics, Maastricht University Medical Centre (MUMC), Maastricht, The Netherlands.,Research School for Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Alexandra T M Hendrickx
- Department of Clinical Genetics, Maastricht University Medical Centre (MUMC), Maastricht, The Netherlands
| | - Debby M E I Hellebrekers
- Department of Clinical Genetics, Maastricht University Medical Centre (MUMC), Maastricht, The Netherlands
| | - Irenaeus F M de Coo
- Department of Neurology, Erasmus MC-Sophia Children's Hospital Rotterdam, Rotterdam, The Netherlands
| | - Charlotte L Alston
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Charlotte Knowles
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Hubert J M Smeets
- Department of Clinical Genetics, Maastricht University Medical Centre (MUMC), Maastricht, The Netherlands.,Research School for Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands.,Research School for Cardiovascular Diseases in Maastricht, CARIM, Maastricht University, Maastricht, The Netherlands
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37
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Mohanty K, Dada R, Dada T. Neurodegenerative Eye Disorders: Role of Mitochondrial Dynamics and Genomics. Asia Pac J Ophthalmol (Phila) 2016; 5:293-9. [PMID: 27101384 DOI: 10.1097/apo.0000000000000203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
As a major source of cellular energy, mitochondria are critical for optimal ocular function. They are also essential for cell differentiation and survival. Mitochondrial mutations and oxidative damage to the mitochondrial DNA are important factors underlying the pathology of many ocular disorders. With increasing age, mitochondrial DNA damage accumulates and results in several eye diseases. It is evident that the mitochondrial genome is more susceptible to stress and damage than the nuclear genome, as it lacks histone protection, a nucleotide excision repair system, and recombination repair, and it is the source and target of free radicals. Accumulation of mitochondrial mutations beyond a certain threshold explains the marked variations in phenotypes seen in mitochondrial diseases and the molecular mechanisms related to the pathogenesis of several chronic disorders in the eye. This review details the structure and function of mitochondria and the mitochondrial genome along with the mitochondrial involvement in various neurodegenerative ophthalmic disorders.
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Affiliation(s)
- Kuldeep Mohanty
- From the *Department of Ophthalmology, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India; and †Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, AIIMS, New Delhi, India
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38
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Ng YS, Turnbull DM. Mitochondrial disease: genetics and management. J Neurol 2016; 263:179-91. [PMID: 26315846 PMCID: PMC4723631 DOI: 10.1007/s00415-015-7884-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/14/2022]
Abstract
Mitochondrial disease is one of the most common groups of genetic diseases with a minimum prevalence of greater than 1 in 5000 in adults. Whilst multi-system involvement is often evident, neurological manifestation is the principal presentation in most cases. The multiple clinical phenotypes and the involvement of both the mitochondrial and nuclear genome make mitochondrial disease particularly challenging for the clinician. In this review article we cover mitochondrial genetics and common neurological presentations associated with adult mitochondrial disease. In addition, specific and supportive treatments are discussed.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
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39
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Lightowlers RN, Taylor RW, Turnbull DM. Mutations causing mitochondrial disease: What is new and what challenges remain? Science 2015; 349:1494-9. [PMID: 26404827 DOI: 10.1126/science.aac7516] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondrial diseases are among the most common and most complex of all inherited genetic diseases. The involvement of both the mitochondrial and nuclear genome presents unique challenges, but despite this there have been some remarkable advances in our knowledge of mitochondrial diseases over the past few years. A greater understanding of mitochondrial genetics has led to improved diagnosis as well as novel ways to prevent transmission of severe mitochondrial disease. These and other advances have had a major impact on patient care, but considerable challenges remain, particularly in the areas of therapies for those patients manifesting clinical symptoms associated with mitochondrial dysfunction and the tissue specificity seen in many mitochondrial disorders. This review highlights some important recent advances in mitochondrial disease but also stresses the areas where progress is essential.
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Affiliation(s)
- Robert N Lightowlers
- Wellcome Trust Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences and Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences and Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences and Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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40
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Abstract
INTRODUCTION OR BACKGROUND The UK is at the forefront of mitochondrial science and is currently the only country in the world to legalize germ-line technologies involving mitochondrial donation. However, concerns have been raised about genetic modification and the 'slippery slope' to designer babies. SOURCES OF DATA This review uses academic articles, newspaper reports and public documents. AREAS OF AGREEMENT Mitochondrial donation offers women with mitochondrial disease an opportunity to have healthy, genetically related children. AREAS OF CONTROVERSY Key areas of disagreement include safety, the creation of three-parent babies, impact on identity, implications for society, definitions of genetic modification and reproductive choice. GROWING POINTS The UK government legalized the techniques in March 2015. Scientific and medical communities across the world followed the developments with interest. AREAS TIMELY FOR DEVELOPING RESEARCH It is expected that the first cohort of 'three parent' babies will be born in the UK in 2016. Their health and progress will be closely monitored.
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Affiliation(s)
- Rebecca Dimond
- Cardiff School of Social Sciences, Cardiff University, Cardiff, UK
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41
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Ma J, Purcell H, Showalter L, Aagaard KM. Mitochondrial DNA sequence variation is largely conserved at birth with rare de novo mutations in neonates. Am J Obstet Gynecol 2015; 212:530.e1-8. [PMID: 25687567 DOI: 10.1016/j.ajog.2015.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/29/2015] [Accepted: 02/09/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Mitochondrial DNA (mtDNA) encodes the proteins of the electron transfer chain to produce adenosine triphosphate through oxidative phosphorylation, and is essential to sustain life. mtDNA is unique from the nuclear genome in so much as it is solely maternally inherited (non-mendelian patterning), and shows a relatively high rate of mutation due to the absence of error checking capacity. While it is generally assumed that most new mutations accumulate through the process of heteroplasmy, it is unknown whether mutations initiated in the mother are inherited, occur in utero, or occur and accumulate early in life. The purpose of this study is to examine the maternally heritable and de novo mutation rate in the fetal mtDNA through high-fidelity sequencing from a large population-based cohort. STUDY DESIGN Samples were obtained from 90 matched maternal (blood) and fetal (placental) pairs. In addition, a smaller cohort (n = 5) of maternal (blood), fetal (placental), and neonatal (cord blood) trios were subjected to DNA extraction and shotgun sequencing. The whole genome was sequenced on the Illumina HiSeq platform (Illumina Inc., San Diego, CA), and haplogroups and mtDNA variants were identified through mapping to reference mitochondrial genomes (NC_012920). RESULTS We observed 665 single nucleotide polymorphisms and 82 insertions-deletions variants identified in the cohort at large. We achieved high sequencing depth of the mtDNA to an average depth of 65X (range, 20-171X) coverage. The proportions of haplogroups identified in the cohort are consistent with the patient's self-identified ethnicity (>90% Hispanic), and all maternal-fetal pairs mapped to the identical haplogroup. Only variants from samples with average depth >20X and allele frequency >1% were included for further analysis. While the majority of the maternal-fetal pairs (>90%) demonstrated identical variants at the single nucleotide level, we observed rare mitochondrial single nucleotide polymorphism discordance between maternal and fetal mitochondrial genomes. CONCLUSION In this first in-depth sequencing analysis of mtDNA from maternal-fetal pairs at the time of birth, a low rate of de novo mutations appears in the fetal mitochondrial genome. This implies that these mutations likely arise from the maternal heteroplasmic pool (eg, in the oocyte), and accumulate later in the offspring's life. These findings have key implications for both the occurrence and screening for mitochondrial disorders.
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