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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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Borna NN, Kishita Y, Ishikawa K, Nakada K, Hayashi JI, Tokuzawa Y, Kohda M, Nyuzuki H, Yamashita-Sugahara Y, Nasu T, Takeda A, Murayama K, Ohtake A, Okazaki Y. A novel mutation in TAZ causes mitochondrial respiratory chain disorder without cardiomyopathy. J Hum Genet 2017; 62:539-547. [PMID: 28123175 DOI: 10.1038/jhg.2016.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 11/17/2016] [Accepted: 12/08/2016] [Indexed: 12/15/2022]
Abstract
Tafazzin, encoded by the TAZ gene, is a mitochondrial membrane-associated protein that remodels cardiolipin (CL), an important mitochondrial phospholipid. TAZ mutations are associated with Barth syndrome (BTHS). BTHS is an X-linked multisystemic disorder affecting usually male patients. Through sequence analysis of TAZ, we found one novel mutation c.39_60del p.(Pro14Alafs*19) by whole-exome sequencing and a reported missense mutation c.280C>T p.(Arg94Cys) by Sanger sequencing in two male patients (Pt1 and Pt2). Patient with c.280C>T mutation had dilated cardiomyopathy, while another patient with c.39_60del mutation had no feature of cardiomyopathy. A reported m.1555A>G homoplasmic variant was also identified in the patient having mutation c.39_60del by whole mitochondrial DNA sequencing method. This variant was not considered to be the main cause of mitochondrial dysfunction based on a cytoplasmic hybrid (cybrid) assay. Tafazzin expression was absent in both patient-derived fibroblast cells. Complementation of TAZ expression in fibroblasts from the patient with the novel mutation c.39_60del restored mitochondrial respiratory complex assembly. High-performance liquid chromatography-tandem mass spectrometry-based metabolic analysis revealed the decline of CL and the accumulation of monolysocardiolipin, indicating the loss of tafazzin activity. Owing to phenotypic variability, it is difficult to diagnose BTHS based on clinical features only. We conclude that genetic analysis should be performed to avoid underdiagnosis of this potentially life-threatening inborn error of metabolism.
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Affiliation(s)
- Nurun N Borna
- Division of Functional Genomics & Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Yoshihito Kishita
- Division of Functional Genomics & Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Kaori Ishikawa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kazuto Nakada
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Jun-Ichi Hayashi
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yoshimi Tokuzawa
- Division of Functional Genomics & 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
| | - Hiromi Nyuzuki
- Division of Functional Genomics & Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Yzumi Yamashita-Sugahara
- Division of Functional Genomics & Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
| | - Takashi Nasu
- Department of Pediatrics, Obihiro Kosei General Hospital, Obihiro, Japan
| | - Atsuhito Takeda
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Hokkaido, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Akira Ohtake
- Department of Pediatrics, Saitama Medical University, Saitama, Japan
| | - Yasushi Okazaki
- Division of Functional Genomics & 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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Ferri L, Cavicchi C, Fiumara A, Parini R, Guerrini R, Morrone A. Pitfalls in the detection of gross gene rearrangements using MLPA in Fabry disease. Clin Chim Acta 2015; 452:82-6. [PMID: 26528637 DOI: 10.1016/j.cca.2015.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/26/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022]
Abstract
MLPA (Multiplex Ligation-dependent Probe Amplification) is a semiquantitative molecular technique developed to uncover gross gene rearrangements in several monogenic diseases, including the X-linked Fabry disease (FD) caused by mutations in the GLA gene. Heterozygosity of the X chromosome in females makes it important to combine routine sequencing analysis with at least one allelic dosage assay (i.e. MLPA). We identified two new gross GLA gene rearrangements, which were not properly detected by MLPA in male patients with FD. In Patient 1, routine sequencing did not amplify GLA exon 7. MLPA failed to confirm such deletion. An alternative allele dosage, based on the Quantitative Fluorescent Multiplex-PCR (QFM-PCR), confirmed the mutation in the proband and excluded it in the mother, revealing that the mutation was de novo in the proband. Patient 2 harboured a gross GLA gene deletion encompassing almost the entire exon 5, the entire intron 5 and part of exon 6. MLPA confirmed the deletion of exon 5 but missed the partial deletion of exon 6. We characterised the breakpoint (c.652_886del452) and carried out screening for possible heterozygosity among at risk female family members. MLPA can miss some gross GLA gene rearrangements making the combination with other allele dosage assays mandatory to confirm or exclude FD at the molecular level.
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Affiliation(s)
- Lorenzo Ferri
- Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, viale Pieraccini 24, 50139 Firenze, Italy; Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, viale Pieraccini 24, 50139 Firenze, Italy
| | - Catia Cavicchi
- Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, viale Pieraccini 24, 50139 Firenze, Italy
| | - Agata Fiumara
- Center for Inborn Errors of Metabolism, Department of Pediatrics, University of Catania, via S. Sofia 78, 95123 Catania, Italy
| | - Rossella Parini
- Rare Metabolic Diseases Unit, San Gerardo Hospital, via Pergolesi 33, 20900 Monza, Italy
| | - Renzo Guerrini
- Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, viale Pieraccini 24, 50139 Firenze, Italy; Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, viale Pieraccini 24, 50139 Firenze, Italy
| | - Amelia Morrone
- Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, viale Pieraccini 24, 50139 Firenze, Italy; Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, viale Pieraccini 24, 50139 Firenze, Italy.
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