scholarly journals Case Report: Mitochondrial Encephalomyopathy Presents as Epilepsy, Ataxia, and Dystonia With a Rare Mutation in MT-TW

2021 ◽  
Vol 12 ◽  
Author(s):  
Shuang Wang ◽  
Jing Miao ◽  
Jiachun Feng
Keyword(s):  
Muscle Biopsy ◽  
Nuclear Dna ◽  
Genetic Test ◽  
Mitochondrial Diseases ◽  
Internal Capsule ◽  
Mitochondrial Encephalomyopathy ◽  
Normal Brain ◽  
Inherited Disorders ◽  
Rare Mutation ◽  
Test Result

Mitochondrial diseases are a group of common inherited disorders caused by mutations in nuclear DNA or mitochondrial DNA (mtDNA); the clinical phenotype of diseases caused by mutant mtDNA is challenging owing to heteroplasmy of mtDNA and may delay diagnosis and treatment. Herein, we report the case of an adult male who slowly developed epilepsy, ataxia, dystonia, impaired cognition, and hearing impairment over 14 years in the absence of clinical myopathy. His lactate level was normal. Brain computed tomography showed calcifications of the bilateral basal ganglia, thalamus, and cerebellar dentate nuclei. Magnetic resonance imaging revealed multiple lesions in the bilateral internal capsule and periventricular areas, which were hypointense on T1-weighted images and hyperintense on T2-weighted images. The first blood genetic test result was negative. Two years later, a muscle biopsy was performed. Succinate dehydrogenase (SDH) staining showed several ragged blue fibers and atypical strongly SDH-reactive vessels. Cytochrome C oxidase (COX) staining revealed abundant COX-deficient fibers. mtDNA testing of blood and muscle revealed a rare m.5549G>A mutation in the MT-TW gene. It was heteroplasmic, with 5.4% mutant mtDNA in the blood and 61.5% in the muscle. The patient was diagnosed with mitochondrial encephalomyopathy and treated with levetiracetam instead of valproate to reduce possible mitochondrial toxicity. After receiving anti-epileptic drugs and mitochondrial supplements, the patient remained clinically stable. For mitochondrial disease, when mutant mtDNA is not detected in blood, muscle biopsy should be performed in routine analysis, and it should be genetically tested, even if there are no manifestations of myopathy.

scholarly journals Mitochondrial Genetic Drift after Nuclear Transfer in Oocytes

2020 ◽  
Vol 21 (16) ◽  
pp. 5880
Author(s):  
Mitsutoshi Yamada ◽  
Kazuhiro Akashi ◽  
Reina Ooka ◽  
Kenji Miyado ◽  
Hidenori Akutsu
Keyword(s):  
Genetic Drift ◽  
Nuclear Transfer ◽  
Nuclear Dna ◽  
Genetic Material ◽  
Mitochondrial Diseases ◽  
Nuclear Transplantation ◽  
Inherited Disorders ◽  
Mtdna Mutations ◽  
Current State ◽  
A Genome

Mitochondria are energy-producing intracellular organelles containing their own genetic material in the form of mitochondrial DNA (mtDNA), which codes for proteins and RNAs essential for mitochondrial function. Some mtDNA mutations can cause mitochondria-related diseases. Mitochondrial diseases are a heterogeneous group of inherited disorders with no cure, in which mutated mtDNA is passed from mothers to offspring via maternal egg cytoplasm. Mitochondrial replacement (MR) is a genome transfer technology in which mtDNA carrying disease-related mutations is replaced by presumably disease-free mtDNA. This therapy aims at preventing the transmission of known disease-causing mitochondria to the next generation. Here, a proof of concept for the specific removal or editing of mtDNA disease-related mutations by genome editing is introduced. Although the amount of mtDNA carryover introduced into human oocytes during nuclear transfer is low, the safety of mtDNA heteroplasmy remains a concern. This is particularly true regarding donor-recipient mtDNA mismatch (mtDNA–mtDNA), mtDNA-nuclear DNA (nDNA) mismatch caused by mixing recipient nDNA with donor mtDNA, and mtDNA replicative segregation. These conditions can lead to mtDNA genetic drift and reversion to the original genotype. In this review, we address the current state of knowledge regarding nuclear transplantation for preventing the inheritance of mitochondrial diseases.

scholarly journals Treatment for mitochondrial diseases

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tongling Liufu ◽  
Zhaoxia Wang
Keyword(s):  
Clinical Trials ◽  
Nuclear Dna ◽  
Mitochondrial Diseases ◽  
Cochrane Collaboration ◽  
Potential Bias ◽  
Leber Hereditary Optic Neuropathy ◽  
Pharmacological Agents ◽  
Unpublished Studies ◽  
New Treatment ◽  
Allotopic Expression

AbstractMitochondrial diseases are predominantly caused by mutations of mitochondrial or nuclear DNA, resulting in multisystem defects. Current treatments are largely supportive, and the disorders progress relentlessly. Nutritional supplements, pharmacological agents and physical therapies have been used in different clinical trials, but the efficacy of these interventions need to be further evaluated. Several recent reviews discussed some of the interventions but ignored bias in those trials. This review was conducted to discover new studies and grade the original studies for potential bias with revised Cochrane Collaboration guidelines. We focused on seven published studies and three unpublished studies; eight of these studies showed improvement in outcome measurements. In particular, two of the interventions have been tested in studies with strict design, which we believe deserve further clinical trials with a large sample. Additionally, allotopic expression of the ND4 subunit seemed to be an effective new treatment for patients with Leber hereditary optic neuropathy.

scholarly journals Mitochondrial DNA Replacement Techniques to Prevent Human Mitochondrial Diseases

2021 ◽  
Vol 22 (2) ◽  
pp. 551
Author(s):  
Luis Sendra ◽  
Alfredo García-Mares ◽  
María José Herrero ◽  
Salvador F. Aliño
Keyword(s):  
Mitochondrial Dna ◽  
Nuclear Dna ◽  
Genetic Disorders ◽  
Mitochondrial Diseases ◽  
Legal Regulation ◽  
Donor Oocyte ◽  
Legal Position ◽  
Ethical And Legal Issues ◽  
Mitochondrial Replacement Techniques ◽  
Do So

Background: Mitochondrial DNA (mtDNA) diseases are a group of maternally inherited genetic disorders caused by a lack of energy production. Currently, mtDNA diseases have a poor prognosis and no known cure. The chance to have unaffected offspring with a genetic link is important for the affected families, and mitochondrial replacement techniques (MRTs) allow them to do so. MRTs consist of transferring the nuclear DNA from an oocyte with pathogenic mtDNA to an enucleated donor oocyte without pathogenic mtDNA. This paper aims to determine the efficacy, associated risks, and main ethical and legal issues related to MRTs. Methods: A bibliographic review was performed on the MEDLINE and Web of Science databases, along with searches for related clinical trials and news. Results: A total of 48 publications were included for review. Five MRT procedures were identified and their efficacy was compared. Three main risks associated with MRTs were discussed, and the ethical views and legal position of MRTs were reviewed. Conclusions: MRTs are an effective approach to minimizing the risk of transmitting mtDNA diseases, but they do not remove it entirely. Global legal regulation of MRTs is required.

Patient recommendations for content and design for electronic return of genetic test results: An interview study among patients who accessed their genetic test results online (Preprint)

2021 ◽  
Author(s):  
Diane M Korngiebel ◽  
Kathleen McGlone West
Keyword(s):  
Patient Preferences ◽  
Genetic Test ◽  
Smartphone Application ◽  
Patient Portal ◽  
Genetic Test Result ◽  
Test Results ◽  
User Centered Design ◽  
Detailed Report ◽  
Genetic Test Results ◽  
Test Result

BACKGROUND Genetic test results will be increasingly made available electronically as more patient-facing tools are developed; however, little research has been done that collects patient preferences for content and design before creating results templates. OBJECTIVE This study identifies patient preferences for electronic return of genetic test results, including what considerations should be prioritized for content and design. METHODS Following User-Centered Design methods, 59 interviews were conducted using semi-structured protocols. The interviews explored content and design issues for patient portal results return for patients who received electronic results for specific types of genetic tests (pharmacogenomic, hereditary blood disorders, and positive and negative risk results for heritable cancers) or who had electronically received any type of genetic test result as well as a non-genetic test result. RESULTS In general, a majority of participants felt that there always needed to be some clinician involvement in electronic results return and that electronic coversheets with simple summaries would be helpful for facilitating that. Coversheet summaries could accompany, but not replace, the more detailed report. Participants had specific suggestions for those results summaries, such as only reporting the information that was most important for patients to understand, including next steps, and to do so using clear language free of medical jargon. Electronic results return should also include explicit encouragement for patients to contact providers with questions. Finally, many participants preferred to manage their care using their smartphones, particularly in instances where they needed to access health information on the go. CONCLUSIONS Participants recommended that a patient-friendly front section accompany the more detailed report and made suggestions for organization, content, and wording. Many used their smartphones regularly to access test results, therefore, health systems and patient portal software vendors should accommodate smartphone application design and web portal design concomitantly when developing results return platforms. CLINICALTRIAL N/A

scholarly journals Understanding mitochondrial myopathies: a review

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4790 ◽  
Author(s):  
Abhimanyu S. Ahuja
Keyword(s):  
Speech Therapy ◽  
Nuclear Dna ◽  
Severe Disease ◽  
Mitochondrial Diseases ◽  
The Body ◽  
Genetic Mutations ◽  
Mitochondrial Myopathies ◽  
Positive Side ◽  
Organ Systems ◽  
New Research

Mitochondria are small, energy-producing structures vital to the energy needs of the body. Genetic mutations cause mitochondria to fail to produce the energy needed by cells and organs which can cause severe disease and death. These genetic mutations are likely to be in the mitochondrial DNA (mtDNA), or possibly in the nuclear DNA (nDNA). The goal of this review is to assess the current understanding of mitochondrial diseases. This review focuses on the pathology, causes, risk factors, symptoms, prevalence data, symptomatic treatments, and new research aimed at possible preventions and/or treatments of mitochondrial diseases. Mitochondrial myopathies are mitochondrial diseases that cause prominent muscular symptoms such as muscle weakness and usually present with a multitude of symptoms and can affect virtually all organ systems. There is no cure for these diseases as of today. Treatment is generally supportive and emphasizes symptom management. Mitochondrial diseases occur infrequently and hence research funding levels tend to be low in comparison with more common diseases. On the positive side, quite a few genetic defects responsible for mitochondrial diseases have been identified, which are in turn being used to investigate potential treatments. Speech therapy, physical therapy, and respiratory therapy have been used in mitochondrial diseases with variable results. These therapies are not curative and at best help with maintaining a patient’s current abilities to move and function.

The heart in neuromuscular disease: primary mitochondrial diseases

ESC CardioMed ◽  
2018 ◽  
pp. 1528-1530
Author(s):  
Denis Duboc
Keyword(s):  
Neuromuscular Disease ◽  
Nuclear Dna ◽  
Single Cells ◽  
Mitochondrial Diseases ◽  
Respiratory Chain Complexes ◽  
Base Pairs ◽  
Daughter Cells ◽  
Dna Molecule ◽  
Chain Complexes ◽  
Genes Encoding

Mitochondria are responsible for energy production in most eukaryotic cells. Each cell contains at least one mitochondrion and every mitochondrion contains two to ten copies of a circular DNA molecule (mitochondrial DNA or mtDNA). Cardiomyocytes contain approximately 10,000 mtDNA copies. MtDNA is composed of around 16,500 base pairs and 37 genes encoding 13 subunits of the respiratory chain complexes I, III, IV, and V, 22 mitochondrial tRNAs and 2 rRNAs. With each cell division, mitochondria and mtDNA are randomly distributed to daughter cells. In humans, mitochondria are inherited exclusively from the mother. In healthy people mtDNA copies are usually identical at birth (homoplasmy) but with ageing, mtDNA is particularly prone to somatic mutation because, unlike nuclear DNA, it is continuously replicated, even in non-dividing tissues such as myocardium. This can lead to the propagation of somatic mutations within single cells by a process called clonal expansion. In addition, mtDNA lacks an extensive DNA repair mechanism.

scholarly journals Randomized comparison of phone versus in-person BRCA1/2 predisposition genetic test result disclosure counseling

2007 ◽  
Vol 9 (8) ◽  
pp. 487-495 ◽  
Author(s):  
Jean Jenkins ◽  
Kathleen A Calzone ◽  
Eileen Dimond ◽  
David J Liewehr ◽  
Seth M Steinberg ◽  
...  
Keyword(s):  
Genetic Test ◽  
Genetic Test Result ◽  
Test Result

Ethical aspects of a predictive test for Huntington’s Disease

2016 ◽  
Vol 23 (5) ◽  
pp. 565-575 ◽  
Author(s):  
Petra Lilja Andersson ◽  
Åsa Petersén ◽  
Caroline Graff ◽  
Anna-Karin Edberg
Keyword(s):  
Moral Responsibility ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Suicide Attempts ◽  
Genetic Test ◽  
Predictive Test ◽  
The Family ◽  
Long Term Consequences ◽  
Test Result

Background: A predictive genetic test for Huntington’s disease can be used before any symptoms are apparent, but there is only sparse knowledge about the long-term consequences of a positive test result. Such knowledge is important in order to gain a deeper understanding of families’ experiences. Objectives: The aim of the study was to describe a young couple’s long-term experiences and the consequences of a predictive test for Huntington’s disease. Research design: A descriptive case study design was used with a longitudinal narrative life history approach. Participants and research context: The study was based on 18 interviews with a young couple, covering a period of 2.5 years; starting 6 months after the disclosure of the test results showing the woman to be a carrier of the gene causing Huntington’s disease. Ethical considerations: Even though the study was extremely sensitive, where potential harm constantly had to be balanced against the benefits, the couple had a strong wish to contribute to increased knowledge about people in their situation. The study was approved by the ethics committee. Findings: The results show that the long-term consequences were devastating for the family. This 3-year period was characterized by anxiety, repeated suicide attempts, financial difficulties and eventually divorce. Discussion: By offering a predictive test, the healthcare system has an ethical and moral responsibility. Once the test result is disclosed, the individual and the family cannot live without the knowledge it brings. Support is needed in a long-term perspective and should involve counselling concerning the families’ everyday life involving important decision-making, reorientation towards a new outlook of the future and the meaning of life. Conclusion: As health professionals, our ethical and moral responsibility thus embraces not only the phase in direct connection to the actual genetic test but also a commitment to provide support to help the family deal with the long-term consequences of the test.

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