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A high mutation load of m.14597A>G in MT-ND6 causes Leigh syndrome. Sci Rep 2021; 11:11123. [PMID: 34045482 PMCID: PMC8160132 DOI: 10.1038/s41598-021-90196-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/06/2021] [Indexed: 01/13/2023] Open
Abstract
Leigh syndrome (LS) is an early-onset progressive neurodegenerative disorder associated with mitochondrial deficiency. m.14597A>G (p.Ile26Thr) in the MT-ND6 gene was reported to cause Leberʼs hereditary optic neuropathy (LHON) or dementia/dysarthria. In previous reports, less than 90% heteroplasmy was shown to result in adult-onset disease. Here, by whole mitochondrial sequencing, we identified m.14597A>G mutation of a patient with LS. PCR–RFLP analysis on fibroblasts from the patient revealed a high mutation load (> 90% heteroplasmy). We performed functional assays using cybrid cell models generated by fusing mtDNA-less rho0 HeLa cells with enucleated cells from patient fibroblasts carrying the m.14597A>G variant. Cybrid cell lines bearing the m.14597A>G variant exhibited severe effects on mitochondrial complex I activity. Additionally, impairment of cell proliferation, decreased ATP production and reduced oxygen consumption rate were observed in the cybrid cell lines bearing the m.14597A>G variant when the cells were metabolically stressed in medium containing galactose, indicating mitochondrial respiratory chain defects. These results suggest that a high mutation load of m.14597A>G leads to LS via a mitochondrial complex I defect, rather than LHON or dementia/dysarthria.
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Garlid AO, Schaffer CT, Kim J, Bhatt H, Guevara-Gonzalez V, Ping P. TAZ encodes tafazzin, a transacylase essential for cardiolipin formation and central to the etiology of Barth syndrome. Gene 2019; 726:144148. [PMID: 31647997 DOI: 10.1016/j.gene.2019.144148] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 09/12/2019] [Accepted: 09/27/2019] [Indexed: 12/31/2022]
Abstract
Tafazzin, which is encoded by the TAZ gene, catalyzes transacylation to form mature cardiolipin and shows preference for the transfer of a linoleic acid (LA) group from phosphatidylcholine (PC) to monolysocardiolipin (MLCL) with influence from mitochondrial membrane curvature. The protein contains domains and motifs involved in targeting, anchoring, and an active site for transacylase activity. Tafazzin activity affects many aspects of mitochondrial structure and function, including that of the electron transport chain, fission-fusion, as well as apoptotic signaling. TAZ mutations are implicated in Barth syndrome, an underdiagnosed and devastating disease that primarily affects male pediatric patients with a broad spectrum of disease pathologies that impact the cardiovascular, neuromuscular, metabolic, and hematologic systems.
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Affiliation(s)
- Anders O Garlid
- Cardiovascular Data Science Training Program at UCLA, University of California at Los Angeles, CA 90095, USA; Department of Physiology, University of California at Los Angeles, CA 90095, USA.
| | - Calvin T Schaffer
- Cardiovascular Data Science Training Program at UCLA, University of California at Los Angeles, CA 90095, USA; Department of Physiology, University of California at Los Angeles, CA 90095, USA
| | - Jaewoo Kim
- Cardiovascular Data Science Training Program at UCLA, University of California at Los Angeles, CA 90095, USA; Department of Physiology, University of California at Los Angeles, CA 90095, USA
| | - Hirsh Bhatt
- Cardiovascular Data Science Training Program at UCLA, University of California at Los Angeles, CA 90095, USA; Department of Physiology, University of California at Los Angeles, CA 90095, USA
| | - Vladimir Guevara-Gonzalez
- Cardiovascular Data Science Training Program at UCLA, University of California at Los Angeles, CA 90095, USA; Department of Mathematics, University of California at Los Angeles, CA 90095, USA
| | - Peipei Ping
- Cardiovascular Data Science Training Program at UCLA, University of California at Los Angeles, CA 90095, USA; Department of Physiology, University of California at Los Angeles, CA 90095, USA; Department of Medicine/Cardiology, University of California at Los Angeles, CA 90095, USA; Department of Bioinformatics, University of California at Los Angeles, CA 90095, USA; Scalable Analytics Institute (ScAi), University of California at Los Angeles, CA 90095, USA.
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Finsterer J. Barth syndrome: mechanisms and management. APPLICATION OF CLINICAL GENETICS 2019; 12:95-106. [PMID: 31239752 PMCID: PMC6558240 DOI: 10.2147/tacg.s171481] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/04/2019] [Indexed: 12/21/2022]
Abstract
Objectives: Barth syndrome is an ultra-rare, infantile-onset, X-linked recessive mitochondrial disorder, primarily affecting males, due to variants in TAZ encoding for the cardiolipin transacylase tafazzin. This review aimed to summarize and discuss recent and earlier findings concerning the etiology, pathogenesis, clinical presentation, diagnosis, treatment, and outcome of Barth syndrome. Method: A literature review was undertaken through a MEDLINE search. Results: The phenotype of Barth syndrome is highly variable but most frequently patients present with hypertrophic/dilated/non-compaction cardiomyopathy, fibroelastosis, arrhythmias, neutropenia, mitochondrial myopathy, growth retardation, dysmorphism, cognitive impairment, and other, rarer features. Lactic acid and creatine kinase, and blood and urine organic acids, particularly 3-methylglutaconic acid and monolysocardiolipin, are often elevated. Cardiolipin is decreased. Biochemical investigations may show decreased activity of various respiratory chain complexes. The diagnosis is confirmed by documentation of a causative TAZ variant. Treatment is symptomatic and directed toward treating heart failure, arrhythmias, neutropenia, and mitochondrial myopathy. Conclusions: Although Barth syndrome is still an orphan disease, with fewer than 200 cases described so far, there is extensive ongoing research with regard to its pathomechanism and new therapeutic approaches. Although most of these approaches are still experimental, it can be expected that causative strategies will be developed in the near future.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Messerli Institute, Vienna, Austria
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Imai-Okazaki A, Kishita Y, Kohda M, Mizuno Y, Fushimi T, Matsunaga A, Yatsuka Y, Hirata T, Harashima H, Takeda A, Nakaya A, Sakata Y, Kogaki S, Ohtake A, Murayama K, Okazaki Y. Cardiomyopathy in children with mitochondrial disease: Prognosis and genetic background. Int J Cardiol 2019; 279:115-121. [PMID: 30642647 DOI: 10.1016/j.ijcard.2019.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/30/2018] [Accepted: 01/03/2019] [Indexed: 01/27/2023]
Abstract
BACKGROUND Cardiomyopathy is a reported indicator of poor prognosis in children with mitochondrial disease. However, the association between prognosis and the genetic background of cardiomyopathy in children with mitochondrial disease has yet to be fully elucidated. METHODS AND RESULTS Of 137 children with mitochondrial disease whose genetic diagnosis was made between 2004 and 2018, 29 had mitochondrial cardiomyopathy (21%). After a median follow-up of 35 months, the overall survival rate was significantly lower in patients with cardiomyopathy than in those without (p < 0.001). Ten-year Kaplan-Meier estimates of overall survival were 18 and 67%, respectively. Among the 21 cardiomyopathy patients who died, two died within one month of birth (COQ4 in one patient, and COX10 in one patient), ten died within one year (BOLA3 in three patients, QRSL1 in two patients, large chromosomal deletions in two patients, MT-ATP6/8 in one patient, MT-TL1 in one patient, and TAZ gene in one patient), and nine died after one year (MT-ND5 in three patients, MT-TL1 in three patients, ACAD9 in one patient, KARS in one patient, and MT-TV in one patient). In the three patients with mitochondrial DNA mutations whose cardiac tissues were available, high heteroplasmy rates in the cardiac tissue were observed for m.8528T>C (90%, died at 2 months of age) and m.3243A>G (90 and 80%, died at 12 and 13 years of age, respectively). CONCLUSIONS In children with mitochondrial disease, cardiomyopathy was common (21%) and was associated with increased mortality. Genetic analysis coupled with detailed phenotyping could be useful for prognosis.
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Affiliation(s)
- Atsuko Imai-Okazaki
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan; Department of Genome Informatics, Osaka University Graduate School of Medicine, Osaka, Japan; Division of Genomic Medicine Research, Medical Genomics Center, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yoshihito Kishita
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Masakazu Kohda
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yosuke Mizuno
- Division of Analytical Science, Biomedical Research Center Hidaka Brunch, Saitama Medical University, Saitama, Japan
| | - Takuya Fushimi
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Ayako Matsunaga
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yukiko Yatsuka
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Tomoko Hirata
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan
| | - Hiroko Harashima
- Department of Pediatrics, Saitama Medical University, Saitama, Japan
| | - Atsuhito Takeda
- Department of Pediatrics, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Akihiro Nakaya
- Department of Genome Informatics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yasushi Sakata
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shigetoyo Kogaki
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Akira Ohtake
- Department of Pediatrics, Saitama Medical University, Saitama, Japan; Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yasushi Okazaki
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan; Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan.
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Imai-Okazaki A, Kishita Y, Kohda M, Yatsuka Y, Hirata T, Mizuno Y, Harashima H, Hirono K, Ichida F, Noguchi A, Yoshida M, Tokorodani C, Nishiuchi R, Takeda A, Nakaya A, Sakata Y, Murayama K, Ohtake A, Okazaki Y. Barth Syndrome: Different Approaches to Diagnosis. J Pediatr 2018; 193:256-260. [PMID: 29249525 DOI: 10.1016/j.jpeds.2017.09.075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/18/2017] [Accepted: 09/27/2017] [Indexed: 12/28/2022]
Abstract
The diagnosis of Barth syndrome is challenging owing to the wide phenotypic spectrum with allelic heterogeneity. Here we report 3 cases of Barth syndrome with phenotypic and allelic heterogeneity that were diagnosed by different approaches, including whole exome sequencing and final confirmation by reverse-transcription polymease chain reaction.
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Affiliation(s)
- Atsuko Imai-Okazaki
- Department of Genome Informatics, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan; Division of Genomic Medicine Research, Medical Genomics Center, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yoshihito Kishita
- Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Masakazu Kohda
- Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Yukiko Yatsuka
- Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Tomoko Hirata
- Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Yosuke Mizuno
- Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Hiroko Harashima
- Department of Pediatrics, Saitama Medical University, Saitama, Japan
| | - Keiichi Hirono
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Fukiko Ichida
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Atsuko Noguchi
- Department of Pediatrics, Graduate School of Medicine, Akita University, Akita, Japan
| | - Masayuki Yoshida
- Department of Molecular Pathology and Tumor Pathology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Chiho Tokorodani
- Department of Pediatrics, Kochi Health Sciences Center, Kochi, Japan
| | - Ritsuo Nishiuchi
- Department of Pediatrics, Kochi Health Sciences Center, Kochi, Japan
| | - Atsuhito Takeda
- Department of Pediatrics, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Akihiro Nakaya
- Department of Genome Informatics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yasushi Sakata
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Akira Ohtake
- Department of Pediatrics, Saitama Medical University, Saitama, Japan; Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Yasushi Okazaki
- Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan; Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan.
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