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Thompson WR, Manuel R, Abbruscato A, Carr J, Campbell J, Hornby B, Vaz FM, Vernon HJ. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. Genet Med 2024; 26:101138. [PMID: 38602181 DOI: 10.1016/j.gim.2024.101138] [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: 12/24/2023] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/12/2024] Open
Abstract
PURPOSE Evaluate long-term efficacy and safety of elamipretide during the open-label extension (OLE) of the TAZPOWER trial in individuals with Barth syndrome (BTHS). METHODS TAZPOWER was a 28-week randomized, double-blind, and placebo-controlled trial followed by a 168-week OLE. Patients entering the OLE continued elamipretide 40 mg subcutaneous daily. OLE primary endpoints were safety and tolerability; secondary endpoints included change from baseline in the 6-minute walk test (6MWT) and BarTH Syndrome Symptom Assessment (BTHS-SA) Total Fatigue score. Muscle strength, physician- and patient-assessed outcomes, echocardiographic parameters, and biomarkers, including cardiolipin (CL) and monolysocardiolipin (MLCL), were assessed. RESULTS Ten patients entered the OLE; 8 reached the week 168 visit. Elamipretide was well tolerated, with injection-site reactions being the most common adverse events. Significant improvements from OLE baseline on 6MWT occurred at all OLE time points (cumulative 96.1 m of improvement [week 168, P = .003]). Mean BTHS-SA Total Fatigue scores were below baseline (improved) at all OLE time points. Three-dimensional (3D) left ventricular stroke, end-diastolic, and end-systolic volumes improved, showing significant trends for improvement from baseline to week 168. MLCL/CL values showed improvement, correlating to important clinical outcomes. CONCLUSION Elamipretide was associated with sustained long-term tolerability and efficacy, with improvements in functional assessments and cardiac function in BTHS.
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Affiliation(s)
- William R Thompson
- The Blalock-Taussig-Thomas Pediatric and Congenital Heart Center, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ryan Manuel
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | | | - Jim Carr
- Stealth BioTherapeutics, Inc., Newton, MA
| | | | - Brittany Hornby
- Department of Physical Therapy, Kennedy Krieger, Baltimore, MD
| | - Frédéric M Vaz
- Amsterdam UMC Location University of Amsterdam, Department of Clinical Chemistry and Pediatrics, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Meibergdreef 9, Amsterdam, The Netherlands; Amsterdam Gastroenterology Endocrinology Metabolism, Inborn Errors of Metabolism, Amsterdam, The Netherlands; Core Facility Metabolomics, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
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2
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Lim Y, Hong I, Han A. The Impact of Raising Children with Barth Syndrome on Parental Health-Related Quality of Life and Family Functioning: Preliminary Reliability and Validity of the PedsQL™ Family Impact Module. Occup Ther Int 2023; 2023:5588935. [PMID: 38187035 PMCID: PMC10771332 DOI: 10.1155/2023/5588935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/02/2023] [Accepted: 12/21/2023] [Indexed: 01/09/2024] Open
Abstract
Objective This study examined the preliminary reliability and validity of the PedsQL™ Family Impact Module (PedsQL FIM) in families of children with Barth syndrome (BTHS). Method A total of 72 parents with children or youth between the ages of 5 and 19 participated in this study. Thirty-three parents of children with BTHS and 39 parents of unaffected children completed the PedsQL FIM and a demographic information form. Internal consistency reliability and item-total correlations were calculated to test the reliability of the PedsQL FIM. Construct validity was examined using the known-groups method. We estimated the mean score differences of the PedsQL FIM between the two groups using three different models, including unadjusted, multivariate regression, and propensity score matching with inverse probability of treatment weighting (PS-IPTW) models. Results The Cronbach's alpha coefficients were greater than 0.70 for all scales of the PedsQL FIM, except for the communication scale. The item-total correlations were significant for all scales with moderate to high correlations (p < .05). In construct validity, the mean scores of the PedsQL FIM between the two groups were significantly different (p < .05) for all scales and total score in the unadjusted and PS-IPTW models. However, in the multivariate regression model, the family relationships scale was not significant between the two groups. Conclusion The PedsQL FIM demonstrated adequate measurement properties of preliminary reliability and validity in assessing the impact of children with BTHS on parental health-related quality of life (HRQoL) and family functioning. Further research needs to be conducted to examine the psychometric properties of the PedsQL FIM with a large sample of BTHS and with other pediatric rare diseases.
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Affiliation(s)
- Yoonjeong Lim
- Division of Occupational Therapy, Binghamton University, Johnson City, NY 13790, USA
| | - Ickpyo Hong
- Department of Occupational Therapy, Yonsei University, Wonju 26493, Republic of Korea
| | - Areum Han
- Department of Occupational Therapy, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Liu O, Chinni BK, Manlhiot C, Vernon HJ. FGF21 and GDF15 are elevated in Barth Syndrome and are correlated to important clinical measures. Mol Genet Metab 2023; 140:107676. [PMID: 37549445 DOI: 10.1016/j.ymgme.2023.107676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/09/2023]
Abstract
Barth Syndrome (BTHS) is a rare X-linked disorder that is caused by defects TAFAZZIN, which leads to an abnormal cardiolipin (CL) profile of the inner mitochondrial membrane and clinical features including cardiomyopathy, neutropenia and skeletal myopathy. The ratio of monolysocardiolipin (MLCL, the remodeling intermediate of cardiolipin) to remodeled CL is always abnormal in Barth Syndrome and 3-methylglutaconic acid is often elevated affected patients, however neither of these biomarkers has been shown to temporally correlate to clinical status. In this study, we measured plasma FGF21 and GDF15 levels in 16 individuals with Barth Syndrome and evaluated whether these biomarkers were correlated to the MLCL/CL ratio in patient bloodspots and clinical laboratory parameters indicative of organ involvement in Barth Syndrome including: neutrophil and monocyte counts, liver function, and cardiac function (NT-proBNP). We found that FGF21 and GDF15 were elevated in all 16 patients and that FGF21 was significantly correlated to AST, ALT GGT, percentage of neutrophils comprising total white blood cells, percent monocytes comprising total white blood cells, and NT-proBNP levels. GDF-15 was significantly positively associated with NT-proBNP. We conclude that clinical measurements of FGF21 and GDF-15 may be relevant in the monitoring multi-organ system involvement in Barth Syndrome.
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Affiliation(s)
- Olivia Liu
- The Blalock-Taussig-Thomas Pediatric and Congenital Heart Center, Department of Pediatrics, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Bhargava Kumar Chinni
- The Blalock-Taussig-Thomas Pediatric and Congenital Heart Center, Department of Pediatrics, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Cedric Manlhiot
- The Blalock-Taussig-Thomas Pediatric and Congenital Heart Center, Department of Pediatrics, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA..
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4
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Joshi A, Richard TH, Gohil VM. Mitochondrial phospholipid metabolism in health and disease. J Cell Sci 2023; 136:jcs260857. [PMID: 37655851 PMCID: PMC10482392 DOI: 10.1242/jcs.260857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
Abstract
Studies of rare human genetic disorders of mitochondrial phospholipid metabolism have highlighted the crucial role that membrane phospholipids play in mitochondrial bioenergetics and human health. The phospholipid composition of mitochondrial membranes is highly conserved from yeast to humans, with each class of phospholipid performing a specific function in the assembly and activity of various mitochondrial membrane proteins, including the oxidative phosphorylation complexes. Recent studies have uncovered novel roles of cardiolipin and phosphatidylethanolamine, two crucial mitochondrial phospholipids, in organismal physiology. Studies on inter-organellar and intramitochondrial phospholipid transport have significantly advanced our understanding of the mechanisms that maintain mitochondrial phospholipid homeostasis. Here, we discuss these recent advances in the function and transport of mitochondrial phospholipids while describing their biochemical and biophysical properties and biosynthetic pathways. Additionally, we highlight the roles of mitochondrial phospholipids in human health by describing the various genetic diseases caused by disruptions in their biosynthesis and discuss advances in therapeutic strategies for Barth syndrome, the best-studied disorder of mitochondrial phospholipid metabolism.
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Affiliation(s)
- Alaumy Joshi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Travis H. Richard
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Vishal M. Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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5
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Tovaglieri N, Russo S, Micaglio E, Corcelli A, Lobasso S. Case report: Variability in clinical features as a potential pitfall for the diagnosis of Barth syndrome. Front Pediatr 2023; 11:1250772. [PMID: 37654687 PMCID: PMC10467424 DOI: 10.3389/fped.2023.1250772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023] Open
Abstract
Background Barth syndrome is a rare genetic disease characterized by cardiomyopathy, skeletal muscle weakness, neutropenia, growth retardation and organic aciduria. This variable phenotype is caused by pathogenic hemizygous variants of the TAFAZZIN gene on the X chromosome, which impair metabolism of the mitochondrial phospholipid cardiolipin. Although most patients are usually diagnosed in the first years of life, the extremely variable clinical picture and the wide range of clinical presentations may both delay diagnosis. This is the case reported here of a man affected with severe neutropenia, who was not diagnosed with Barth syndrome until adulthood. Case presentation We describe herein a family case, specifically two Caucasian male cousins sharing the same mutation in the TAFAZZIN gene with a wide phenotypic variability: an infant who was early diagnosed with Barth syndrome due to heart failure, and his maternal cousin with milder and extremely different clinical features who has received the same diagnosis only at 33 years of age. Conclusions Our report supports the underestimation of the prevalence of Barth syndrome, which should be always considered in the differential diagnosis of male patients with recurrent neutropenia with or without signs and symptoms of cardiomyopathy.
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Affiliation(s)
| | - Silvia Russo
- Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
| | - Emanuele Micaglio
- Department of Arrhythmology and Clinical Electrophysiology, Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinic San Donato, Milan, Italy
| | - Angela Corcelli
- Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
| | - Simona Lobasso
- Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
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6
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Olivar-Villanueva M, Ren M, Schlame M, Phoon CK. The critical role of cardiolipin in metazoan differentiation, development, and maturation. Dev Dyn 2023; 252:691-712. [PMID: 36692477 PMCID: PMC10238668 DOI: 10.1002/dvdy.567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 12/27/2022] [Accepted: 01/13/2023] [Indexed: 01/25/2023] Open
Abstract
Cardiolipins are phospholipids that are central to proper mitochondrial functioning. Because mitochondria play crucial roles in differentiation, development, and maturation, we would also expect cardiolipin to play major roles in these processes. Indeed, cardiolipin has been implicated in the mechanism of three human diseases that affect young infants, implying developmental abnormalities. In this review, we will: (1) Review the biology of cardiolipin; (2) Outline the evidence for essential roles of cardiolipin during organismal development, including embryogenesis and cell maturation in vertebrate organisms; (3) Place the role(s) of cardiolipin during embryogenesis within the larger context of the roles of mitochondria in development; and (4) Suggest avenues for future research.
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Affiliation(s)
| | - Mindong Ren
- Department of Anesthesiology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York, USA
| | - Michael Schlame
- Department of Anesthesiology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York, USA
| | - Colin K.L. Phoon
- Department of Pediatrics, New York University Grossman School of Medicine, New York, New York, USA
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7
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Sabbah HN, Taylor C, Vernon HJ. Temporal evolution of the heart failure phenotype in Barth syndrome and treatment with elamipretide. Future Cardiol 2023; 19:211-225. [PMID: 37325898 DOI: 10.2217/fca-2023-0008] [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: 01/17/2023] [Accepted: 04/19/2023] [Indexed: 06/17/2023] Open
Abstract
Barth syndrome (BTHS) is a rare genetic disorder caused by pathogenic variants in TAFAZZIN leading to reduced remodeled cardiolipin (CL), a phospholipid essential to mitochondrial function and structure. Cardiomyopathy presents in most patients with BTHS, typically appearing as dilated cardiomyopathy (DCM) in infancy and evolving to hypertrophic cardiomyopathy (HCM) resembling heart failure (HF) with preserved ejection fraction (HFpEF) in some patients ≥12 years. Elamipretide localizes to the inner mitochondrial membrane where it associates with CL, improving mitochondrial function, structure and bioenergetics, including ATP synthesis. Numerous preclinical and clinical studies in BTHS and other forms of HF have demonstrated that elamipretide improves left ventricular relaxation by ameliorating mitochondrial dysfunction, making it well suited for therapeutic use in adolescent and adult patients with BTHS.
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Affiliation(s)
- Hani N Sabbah
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Hospital, Henry Ford Health, 2799 West Grand Boulevard, Detroit, MI 48202, USA
| | - Carolyn Taylor
- Department of Pediatrics, Division of Cardiology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Phenotypic Characterization of Male Tafazzin-Knockout Mice at 3, 6, and 12 Months of Age. Biomedicines 2023; 11:biomedicines11020638. [PMID: 36831174 PMCID: PMC9953241 DOI: 10.3390/biomedicines11020638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
Barth syndrome (BTHS) is an X-linked mitochondrial disease caused by mutations in the gene encoding for tafazzin (TAZ), a key enzyme in the remodeling of cardiolipin. Mice with a germline deficiency in Taz have been generated (Taz-KO) but not yet fully characterized. We performed physiological assessments of 3-, 6-, and 12-month-old male Taz-KO mice, including measures of perinatal survival, growth, lifespan, gross anatomy, whole-body energy and substrate metabolism, glucose homeostasis, and exercise capacity. Taz-KO mice displayed reduced viability, with lower-than-expected numbers of mice recorded at 4 weeks of age, and a shortened lifespan due to disease progression. At all ages, Taz-KO mice had lower body weights compared with wild-type (Wt) littermates despite similar absolute food intakes. This finding was attributed to reduced adiposity and diminutive organs and tissues, including heart and skeletal muscles. Although there were no differences in basal levels of locomotion between age-matched genotypes, indirect calorimetry studies showed higher energy expenditure measures and respiratory exchange ratios in Taz-KO mice. At the youngest age, Taz-KO mice had comparable glucose tolerance and insulin action to Wt mice, but while these measures indicated metabolic impairments in Wt mice with advancing age that were likely associated with increasing adiposity, Taz-KO mice were protected. Comparisons across the three age-cohorts revealed a significant and more severe deterioration of exercise capacity in Taz-KO mice than in their Wt littermate controls. The Taz-KO mouse model faithfully recapitulates important aspects of BTHS, and thus provides an important new tool to investigate pathophysiological mechanisms and potential therapies.
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9
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Russo S, De Rasmo D, Signorile A, Corcelli A, Lobasso S. Beneficial effects of SS-31 peptide on cardiac mitochondrial dysfunction in tafazzin knockdown mice. Sci Rep 2022; 12:19847. [PMID: 36400945 PMCID: PMC9674582 DOI: 10.1038/s41598-022-24231-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/11/2022] [Indexed: 11/19/2022] Open
Abstract
Barth Syndrome (BTHS), a genetic disease associated with early-onset cardioskeletal myopathy, is caused by loss-of-function mutations of the TAFAZZIN gene, which is responsible for remodeling the mitochondrial phospholipid cardiolipin (CL). Deregulation of CL biosynthesis and maturation in BTHS mitochondria result in a dramatically increased monolysocardiolipin (MLCL)/CL ratio associated with bioenergetic dysfunction. One of the most promising therapeutic approaches for BTHS includes the mitochondria-targeted tetrapeptide SS-31, which interacts with CL. Here, we used TAFAZZIN knockdown (TazKD) mice to investigate for the first time whether in vivo administration of SS-31 could affect phospholipid profiles and mitochondrial dysfunction. The CL fingerprinting of TazKD cardiac mitochondria obtained by MALDI-TOF/MS revealed the typical lipid changes associated with BTHS. TazKD mitochondria showed lower respiratory rates in state 3 and 4 together with a decreased in maximal respiratory rates. Treatment of TazKD mice with SS-31 improved mitochondrial respiratory capacity and promoted supercomplex organization, without affecting the MLCL/CL ratio. We hypothesize that SS-31 exerts its effect by influencing the function of the respiratory chain rather than affecting CL directly. In conclusion, our results indicate that SS-31 have beneficial effects on improving cardiac mitochondrial dysfunction in a BTHS animal model, suggesting the peptide as future pharmacologic agent for therapy.
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Affiliation(s)
- Silvia Russo
- grid.7644.10000 0001 0120 3326Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
| | - Domenico De Rasmo
- grid.503043.1CNR-Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
| | - Anna Signorile
- grid.7644.10000 0001 0120 3326Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
| | - Angela Corcelli
- grid.7644.10000 0001 0120 3326Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
| | - Simona Lobasso
- grid.7644.10000 0001 0120 3326Department of Translational Biomedicine and Neuroscience, University of Bari Aldo Moro, Bari, Italy
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10
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Hornby B, Thompson WR, Almuqbil M, Manuel R, Abbruscato A, Carr J, Vernon HJ. Natural history comparison study to assess the efficacy of elamipretide in patients with Barth syndrome. Orphanet J Rare Dis 2022; 17:336. [PMID: 36056411 PMCID: PMC9438322 DOI: 10.1186/s13023-022-02469-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 08/13/2022] [Indexed: 11/23/2022] Open
Abstract
Background Natural history studies are increasingly recognized as having an important role in drug development for rare diseases. A phase 3, observational, retrospective, and non-interventional study was designed to establish a natural history control (NHC) cohort of patients with Barth syndrome (BTHS) to provide further analysis of the efficacy of elamipretide observed in an open-label extension (OLE) phase of the TAZPOWER trial, a clinical trial that tested the efficacy of 40 mg daily of elamipretide in patients with BTHS. Methods This was a retrospective, non-interventional study. A propensity score model was used to compare elamipretide-treated patients and NHCs. The analysis included 8 patients from the TAZPOWER OLE and 19 untreated NHCs (including 12 with serial echocardiographic assessments). Results For the 6-min walk test (6MWT, primary endpoint), the least squares (LS) mean difference between groups was 79.7 m (P = 0.0004) at week 64 and 91.0 m (P = 0.0005) at week 76 in favor of elamipretide. Significant improvements in muscle strength (secondary endpoint), as assessed by handheld dynamometry (HHD) were also observed with elamipretide, with LS mean differences of 40.8 Newtons at 64 weeks (P = 0.0002) and 56.7 Newtons at 76 weeks (P = 0.0005). Patients continuously treated with elamipretide also experienced statistically significant improvements in other secondary endpoints (i.e., 5 times sit-to-stand [5XSST], multi-domain responder index [MDRI]). The functional improvements were robust to sensitivity analyses. Left ventricular stroke volume increased from baseline in patients with elamipretide but decreased in NHCs.
Conclusions Overall, the study established a NHC for use in assessing the efficacy of therapeutic interventions in patients with BTHS and the results suggest that elamipretide may improve natural history of BTHS at least in part by attenuating the natural decline in heart function and provide meaningful improvements in heart function and functional capacity in patients with BTHS compared to NHCs. Highlights A matched Natural History Control (NHC) was used to evaluate elamipretide in BTHS Elamipretide may improve natural history of BTHS by attenuating natural decline in heart function Elamipretide was associated with meaningful clinical improvements in skeletal muscle and cardiovascular parameters that were not observed in NHCs The study established a NHC for use in assessing the efficacy of therapeutic interventions in BTHS
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Affiliation(s)
- Brittany Hornby
- Department of Physical Therapy, Kennedy Krieger, Baltimore, MD, USA
| | - William Reid Thompson
- Department of Pediatric Cardiology, Taussig Heart Center, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Mohammed Almuqbil
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS); King Abdullah Specialized Children's Hospital (KASCH), Riyadh, Saudi Arabia
| | - Ryan Manuel
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, 733 N Broadway, MRB 512, Baltimore, Maryland, 21205, USA
| | | | - Jim Carr
- Stealth BioTherapeutics, Inc, Needham, MA, USA
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, 733 N Broadway, MRB 512, Baltimore, Maryland, 21205, USA.
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Chowdhury S, Jackson L, Byrne BJ, Bryant RM, Cade WT, Churchill TL, Buchanan J, Taylor C. Longitudinal Observational Study of Cardiac Outcome Risk Factor Prediction in Children, Adolescents, and Adults with Barth Syndrome. Pediatr Cardiol 2022; 43:1251-1263. [PMID: 35238957 PMCID: PMC9462389 DOI: 10.1007/s00246-022-02846-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/04/2022] [Indexed: 12/01/2022]
Abstract
Barth Syndrome (BTHS) is an X-linked mitochondrial cardioskeletal myopathy caused by defects in TAFAZZIN, a gene responsible for cardiolipin remodeling. Altered mitochondrial levels of cardiolipin lead to cardiomyopathy (CM), muscle weakness, exercise intolerance, and mortality. Cardiac risk factors predicting outcome are unknown. Therefore, we conducted a longitudinal observational study to determine risk factors for outcome in BTHS. Subjects with minimum two evaluations (or one followed by death or transplant) were included. Cardiac size, function, and QTc data were measured by echocardiography and electrocardiography at 7 time points from 2002 to 2018. Analysis included baseline, continuous, and categorical variables. Categorical risk factors included prolonged QTc, abnormal right ventricle fractional area change (RV FAC), left ventricle (LV) or RV non-compaction, and restrictive CM phenotype. The association between variables and cardiac death or transplant (CD/TX) was assessed. Median enrollment age was 7 years (range 0.5-22; n = 44). Transplant-free survival (TFS) was 74.4% at 15 years from first evaluation. The cohort demonstrated longitudinal declines in LV size and stroke volume z-scores (end-diastolic volume, p = 0.0002; stroke volume p < 0.0001), worsening RV FAC (p = 0.0405), and global longitudinal strain (GLS) (p = 0.0001) with stable ejection (EF) and shortening (FS) fraction. CD/TX subjects (n = 9) displayed worsening LV dilation (p = 0.0066), EF (p ≤ 0.0001), FS (p = 0.0028), and RV FAC (p = .0032) versus stability in TFS. Having ≥ 2 categorical risk factors predicted CD/TX (p = 0.0073). Over 15 years, 25% of BTHS subjects progressed to CD/TX. Those with progressive LV enlargement, dysfunction, and multiple cardiac risk factors warrant increased surveillance and intense therapy.
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Affiliation(s)
| | - Lanier Jackson
- Medical University of South Carolina, Charleston, SC, USA
| | - Barry J. Byrne
- School of Medicine, University of Florida, Gainesville, FL, USA
| | | | - W. Todd Cade
- Duke University School of Medicine, Durham, NC, USA
| | | | - Julia Buchanan
- Medical University of South Carolina, Charleston, SC, USA
| | - Carolyn Taylor
- MUSC Children's Heart Program, Pediatric Echocardiography Lab, Pediatric Cardiology, Shawn Jenkins Children's Hospital, MSC 915, 10 McClennan Banks Dr., Charleston, SC, 29425-8905, USA.
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Jones DE, Jennings EA, Ryan RO. Diversion of Acetyl CoA to 3-Methylglutaconic Acid Caused by Discrete Inborn Errors of Metabolism. Metabolites 2022; 12:metabo12050377. [PMID: 35629880 PMCID: PMC9146172 DOI: 10.3390/metabo12050377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/16/2022] Open
Abstract
A growing number of inborn errors of metabolism (IEM) have been identified that manifest 3-methylglutaconic (3MGC) aciduria as a phenotypic feature. In primary 3MGC aciduria, IEM-dependent deficiencies in leucine pathway enzymes prevent catabolism of trans-3MGC CoA. Consequently, this metabolite is converted to 3MGC acid and excreted in urine. In secondary 3MGC aciduria, however, no leucine metabolism pathway enzyme deficiencies exist. These IEMs affect mitochondrial membrane structure, electron transport chain function or ATP synthase subunits. As a result, acetyl CoA oxidation via the TCA cycle slows and acetyl CoA is diverted to trans-3MGC CoA, and then to 3MGC acid. Whereas the trans diastereomer of 3MGC CoA is the only biologically relevant diastereomer, the urine of affected subjects contains both cis- and trans-3MGC acids. Studies have revealed that trans-3MGC CoA is susceptible to isomerization to cis-3MGC CoA. Once formed, cis-3MGC CoA undergoes intramolecular cyclization, forming an anhydride that, upon hydrolysis, yields cis-3MGC acid. Alternatively, cis-3MGC anhydride can acylate protein lysine side chains. Once formed, cis-3MGCylated proteins can be deacylated by the NAD+-dependent enzyme, sirtuin 4. Taken together, the excretion of 3MGC acid in secondary 3MGC aciduria represents a barometer of defective mitochondrial function.
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Pang J, Bao Y, Mitchell-Silbaugh K, Veevers J, Fang X. Barth Syndrome Cardiomyopathy: An Update. Genes (Basel) 2022; 13:genes13040656. [PMID: 35456462 PMCID: PMC9030331 DOI: 10.3390/genes13040656] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/23/2022] [Accepted: 04/02/2022] [Indexed: 12/28/2022] Open
Abstract
Barth syndrome (BTHS) is an X-linked mitochondrial lipid disorder caused by mutations in the TAFAZZIN (TAZ) gene, which encodes a mitochondrial acyltransferase/transacylase required for cardiolipin (CL) biosynthesis. Cardiomyopathy is a major clinical feature of BTHS. During the past four decades, we have witnessed many landmark discoveries that have led to a greater understanding of clinical features of BTHS cardiomyopathy and their molecular basis, as well as the therapeutic targets for this disease. Recently published Taz knockout mouse models provide useful experimental models for studying BTHS cardiomyopathy and testing potential therapeutic approaches. This review aims to summarize key findings of the clinical features, molecular mechanisms, and potential therapeutic approaches for BTHS cardiomyopathy, with particular emphasis on the most recent studies.
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Affiliation(s)
- Jing Pang
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (J.P.); (Y.B.); (K.M.-S.); (J.V.)
- Department of Biological Science, University of California San Diego, La Jolla, CA 92093, USA
| | - Yutong Bao
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (J.P.); (Y.B.); (K.M.-S.); (J.V.)
- Department of Biological Science, University of California San Diego, La Jolla, CA 92093, USA
| | - Kalia Mitchell-Silbaugh
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (J.P.); (Y.B.); (K.M.-S.); (J.V.)
| | - Jennifer Veevers
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (J.P.); (Y.B.); (K.M.-S.); (J.V.)
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (J.P.); (Y.B.); (K.M.-S.); (J.V.)
- Correspondence: ; Tel.: +1-858-246-4637
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14
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Kim AY, Vernon H, Manuel R, Almuqbil M, Hornby B. Quality of life in Barth syndrome. THERAPEUTIC ADVANCES IN RARE DISEASE 2022; 3:26330040221093743. [PMID: 37180415 PMCID: PMC10032447 DOI: 10.1177/26330040221093743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/25/2022] [Indexed: 05/16/2023]
Abstract
Introduction Barth syndrome (BTHS) is a rare X-linked disorder characterized by cardiomyopathy, neutropenia, growth abnormalities, and skeletal myopathy. There have been few studies investigating health-related quality of life (HRQoL) in this population. This study investigated the impact of BTHS on HRQoL and select physiologic measures in affected boys and men. Methods In this study, we characterize HRQoL in boys and men with BTHS through cross-sectional analysis of a variety of outcome measures including the Pediatric Quality of Life Inventory (PedsQLTM) Version 4.0 Generic Core Scales, PedsQLTM Multidimensional Fatigue Scale, Barth Syndrome Symptom Assessment, the PROMISTM Fatigue Short Form, the EuroQol Group EQ-5DTM, the Patient Global Impression of Symptoms (PGIS), and the Caregiver Global Impression of Symptoms (CaGIS). For a specific subset of participants, physiologic data were available in addition to HRQoL data. Results For the PedsQLTM questionnaires, 18 unique child and parent reports were analyzed for children aged 5-18 years, and nine unique parent reports were analyzed for children aged 2-4 years. For the other HRQoL outcome measures and physiologic measurements, the data from 12 subjects (age range 12-35 years) were analyzed. Based on parent and child reports, HRQoL is significantly impaired in boys and men with BTHS, especially in school functioning and physical functioning. Parent and child reports of more severe fatigue are significantly correlated with more impaired HRQoL. When exploring the potential relationship between physiology and HRQoL, the CaGIS as a whole for pediatric subjects and individual questionnaire items from the PGIS and CaGIS for pediatric subjects assessing tiredness, muscle weakness, and muscle pain showed the strongest correlations. Conclusion This study provides a unique characterization of the HRQoL in boys and men with BTHS using a variety of outcome measures, and it highlights the negative impact of fatigue and muscle weakness on HRQoL in BTHS. Trial registry name A Trial to Evaluate Safety, Tolerability and Efficacy of Elamipretide in Subjects with Barth Syndrome (TAZPOWER). https://clinicaltrials.gov/ct2/show/NCT03098797.Registration Number: NCT03098797.
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Affiliation(s)
- Alexander Y. Kim
- Division of Genetics, Johns Hopkins All
Children’s Hospital, St. Petersburg, FL, USA
| | - Hilary Vernon
- Department of Genetic Medicine, Johns Hopkins
University School of Medicine, Baltimore, MD, USADepartment of
Neurogenetics, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Ryan Manuel
- Department of Genetic Medicine, Johns Hopkins
University School of Medicine, Baltimore, MD, USA
| | - Mohammed Almuqbil
- College of Medicine, King Saud Bin Abdulaziz
University for Health Sciences (KSAU-HS), Riyadh, Saudi ArabiaDivision of
Pediatric Neurology, King Abdullah Specialist Children’s Hospital (KASCH),
National Guard Health Affairs (NGHA), Riyadh, Saudi ArabiaKing Abdullah
International Medical Research Center (KAIMRC), Ministry of National Guard,
Riyadh, Saudi Arabia
| | - Brittany Hornby
- Physical Therapy Department, Kennedy Krieger
Institute, 801 N Broadway, Baltimore, MD 21205, USA
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15
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Taylor C, Rao ES, Pierre G, Chronopoulou E, Hornby B, Heyman A, Vernon HJ. Clinical presentation and natural history of Barth Syndrome: An overview. J Inherit Metab Dis 2022; 45:7-16. [PMID: 34355402 DOI: 10.1002/jimd.12422] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/23/2021] [Accepted: 08/04/2021] [Indexed: 01/25/2023]
Abstract
Barth Syndrome is a rare X-linked disorder caused by pathogenic variants in the gene TAFAZZIN, which encodes for an enzyme involved in the remodeling of cardiolipin, a phospholipid primarily localized to the inner mitochondrial membrane. Barth Syndrome is characterized by cardiomyopathy, skeletal myopathy, neutropenia, and growth abnormalities, among other features. In this review, we will discuss the clinical presentation and natural history of Barth Syndrome, review key features of this disease, and introduce less common clinical associations. Recognition and understanding of the natural history of Barth Syndrome are important for ongoing patient management and developing endpoints for the demonstration of efficacy of new and emerging therapies.
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Affiliation(s)
- Carolyn Taylor
- Department of Pediatrics, Division of Cardiology, Children's Hospital, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Emily S Rao
- Department of Pediatrics, Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Germaine Pierre
- Department of Inherited Metabolic Disease, Division of Women's and Children's Services, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Estathia Chronopoulou
- Department of Inherited Metabolic Disease, Division of Women's and Children's Services, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Brittany Hornby
- Department of Physical Therapy, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Andrea Heyman
- Department of Nutrition, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Hilary J Vernon
- Department of Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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16
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Xu Y, Phoon CKL, Ren M, Schlame M. A simple mechanistic explanation for Barth syndrome and cardiolipin remodeling. J Inherit Metab Dis 2022; 45:51-59. [PMID: 34611930 DOI: 10.1002/jimd.12445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/24/2021] [Accepted: 10/04/2021] [Indexed: 12/23/2022]
Abstract
Barth syndrome is a multisystem disorder caused by an abnormal metabolism of the mitochondrial lipid cardiolipin. In this review, we discuss physical properties, biosynthesis, membrane assembly, and function of cardiolipin. We hypothesize that cardiolipin reduces packing stress in the inner mitochondrial membrane, which arises as a result of protein crowding. According to this hypothesis, patients with Barth syndrome are unable to meet peak energy demands because they fail to concentrate the proteins of oxidative phosphorylation to a high surface density in the inner mitochondrial membrane.
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Affiliation(s)
- Yang Xu
- Department of Anesthesiology, New York University School of Medicine, New York, New York, USA
| | - Colin K L Phoon
- Department of Pediatrics, New York University School of Medicine, New York, New York, USA
| | - Mindong Ren
- Department of Anesthesiology, New York University School of Medicine, New York, New York, USA
| | - Michael Schlame
- Department of Anesthesiology, New York University School of Medicine, New York, New York, USA
- Department of Cell Biology, New York University School of Medicine, New York, New York, USA
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17
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Zhao X, Li X, Sun W, Jia JA, Yu M, Tian R. Prenatal case report of Barth syndrome caused by novel TAFAZZIN mutation: Clinical characteristics of fetal dilated cardiomyopathy with ascites. Front Pediatr 2022; 10:1004485. [PMID: 36440345 PMCID: PMC9682154 DOI: 10.3389/fped.2022.1004485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/24/2022] [Indexed: 11/10/2022] Open
Abstract
Barth syndrome (BTHS) is a rare X-linked recessive genetic disease, which appears in infancy with myocardial and skeletal muscle diseases, neutropenia, growth retardation, and other clinical features. TAFAZZIN is the pathogenic gene of BTHS, which encodes the tafazzin protein of the inner membrane of the mitochondria, a phosphatidyltransferase involved in cardiolipin remodeling and functional maturation. At present, BTHS has been widely reported, but prenatal cases are rare. We report a 24+4-week fetus with clinical manifestations including left ventricular insufficiency and ascites. After induced labor, whole exome sequencing detection of fetal skin tissue showed that TAFAZZIN had the mutation c.311A > C/p.His104Pro and that his mother was the carrier. This His104Pro mutation has hitherto not been reported, and it is rated as likely to be pathogenic according to the American College of Medical Genetics and Genetics guidelines. Molecular dynamics and protein expression experiments on the His104Pro mutation showed that the stability of the local protein structure and protein expression were reduced. In conclusion, the case presented in this study enriches our knowledge of the TAFAZZIN mutation spectrum and suggests that His104Pro may lead to cardiac structural abnormalities in the early embryo. The possibility of BTHS should be considered when an abnormal cardiac structure or ascites appear in a prenatal ultrasound.
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Affiliation(s)
- Xuliang Zhao
- Department of Laboratory, The 901th Hospital of the Joint Service of the People's Liberation Army, Hefei, China
| | - Xu Li
- Department of Radiology, Anhui Children's Hospital, Hefei, China
| | - Weiwei Sun
- Department of Medical, Beijing Chigene Translational Medicine Research Center, Beijing, China
| | - Jian-An Jia
- Department of Laboratory, The 901th Hospital of the Joint Service of the People's Liberation Army, Hefei, China
| | - Min Yu
- Department of Obstetrics and Gynecology, The 901th Hospital of the Joint Service of the People's Liberation Army, Hefei, China
| | - Ruixia Tian
- Department of Obstetrics and Gynecology, The 901th Hospital of the Joint Service of the People's Liberation Army, Hefei, China
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18
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Vaz FM, van Lenthe H, Vervaart MAT, Stet FS, Klinkspoor JH, Vernon HJ, Goorden SMI, Houtkooper RH, Kulik W, Wanders RJA. An improved functional assay in blood spot to diagnose Barth syndrome using the monolysocardiolipin/cardiolipin ratio. J Inherit Metab Dis 2022; 45:29-37. [PMID: 34382226 PMCID: PMC9291596 DOI: 10.1002/jimd.12425] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/03/2021] [Accepted: 08/09/2021] [Indexed: 12/29/2022]
Abstract
Barth syndrome is an X-linked disorder characterized by cardiomyopathy, skeletal myopathy, and neutropenia, caused by deleterious variants in TAFAZZIN. This gene encodes a phospholipid-lysophospholipid transacylase that is required for the remodeling of the mitochondrial phospholipid cardiolipin (CL). Biochemically, individuals with Barth syndrome have a deficiency of mature CL and accumulation of the remodeling intermediate monolysocardiolipin (MLCL). Diagnosis typically relies on mass spectrometric measurement of CL and MLCL in cells or tissues, and we previously described a method in blood spot that uses a specific MLCL/CL ratio as diagnostic biomarker. Here, we describe the evolution of our blood spot assay that is based on the implementation of reversed phase-UHPLC separation followed by full scan high resolution mass spectrometry. In addition to the MLCL/CL ratio, our improved method also generates a complete CL spectrum allowing the interrogation of the CL fatty acid composition, which considerably enhances the diagnostic reliability. This addition negates the need for a confirmatory test in lymphocytes thereby providing a shorter turn-around-time while achieving a more certain test result. As one of the few laboratories that offer this assay, we also evaluated the diagnostic yield and performance from 2006 to 2021 encompassing the use of both the original and improved assay. In this period, we performed 796 diagnostic analyses of which 117 (15%) were characteristic of Barth syndrome. In total, we diagnosed 93 unique individuals with Barth syndrome, including three females, which together amounts to about 40% of all reported individuals with Barth syndrome in the world.
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Affiliation(s)
- Frédéric M. Vaz
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
- Department of PediatricsEmma Children's Hospital, Amsterdam UMC, University of AmsterdamAmsterdamThe Netherlands
- Core Facility Metabolomics, Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Henk van Lenthe
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
- Core Facility Metabolomics, Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Martin A. T. Vervaart
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
- Core Facility Metabolomics, Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Femke S. Stet
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
- Core Facility Metabolomics, Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Johanne H. Klinkspoor
- Central Diagnostic Laboratory, Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Hilary J. Vernon
- Department of Medical GeneticsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Susan M. I. Goorden
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
| | - Riekelt H. Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
| | - Willem Kulik
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
- Core Facility Metabolomics, Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Ronald J. A. Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and PediatricsAmsterdam Gastroenterology Endocrinology MetabolismAmsterdamThe Netherlands
- Department of PediatricsEmma Children's Hospital, Amsterdam UMC, University of AmsterdamAmsterdamThe Netherlands
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19
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Thompson R, Jefferies J, Wang S, Pu WT, Takemoto C, Hornby B, Heyman A, Chin MT, Vernon HJ. Current and future treatment approaches for Barth syndrome. J Inherit Metab Dis 2022; 45:17-28. [PMID: 34713454 DOI: 10.1002/jimd.12453] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/18/2021] [Accepted: 10/26/2021] [Indexed: 12/17/2022]
Abstract
Barth Syndrome is an X-linked disorder of mitochondrial cardiolipin metabolism caused by pathogenic variants in TAFAZZIN with pleiotropic effects including cardiomyopathy, neutropenia, growth delay, and skeletal myopathy. Management requires a multidisciplinary approach to the organ-specific manifestations including specialists from cardiology, hematology, nutrition, physical therapy, genetics, and metabolism. Currently, treatment is centered on management of specific clinical features, and is not targeted toward remediating the underlying biochemical defect. However, two clinical trials have been recently undertaken which target the mitochondrial pathology of this disease: a study to examine the effects of elamipretide, a cardiolipin targeted agent, and a study to examine the effects of bezafibrate, a peroxisome proliferator-activated receptor (PPAR) agonist. Treatments to directly target the defective TAFAZZIN pathway are under development, including enzyme and gene therapies.
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Affiliation(s)
- Reid Thompson
- Department of Pediatric Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - John Jefferies
- The Cardiovascular Institute, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Suya Wang
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Clifford Takemoto
- Division of Clinical Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Brittany Hornby
- Department of Physical Therapy, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Andrea Heyman
- Department of Nutrition, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Michael T Chin
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Hilary J Vernon
- Department of Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, Maryland, USA
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20
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Collaco JM, Raraigh KS, Betz J, Aksit MA, Blau N, Brown J, Dietz HC, MacCarrick G, Nogee LM, Sheridan MB, Vernon HJ, Beaty TH, Louis TA, Cutting GR. Accurate assignment of disease liability to genetic variants using only population data. Genet Med 2021; 24:87-99. [PMID: 34906463 DOI: 10.1016/j.gim.2021.08.012] [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: 04/05/2021] [Revised: 07/23/2021] [Accepted: 08/17/2021] [Indexed: 10/19/2022] Open
Abstract
PURPOSE The growing size of public variant repositories prompted us to test the accuracy of pathogenicity prediction of DNA variants using population data alone. METHODS Under the a priori assumption that the ratio of the prevalence of variants in healthy population vs that in affected populations form 2 distinct distributions (pathogenic and benign), we used a Bayesian method to assign probability to a variant belonging to either distribution. RESULTS The approach, termed Bayesian prevalence ratio (BayPR), accurately parsed 300 of 313 expertly curated CFTR variants: 284 of 296 pathogenic/likely pathogenic variants in 1 distribution and 16 of 17 benign/likely benign variants in another. BayPR produced an area under the receiver operating characteristic curve of 0.99 for 103 functionally confirmed missense CFTR variants, which is equal to or exceeds 10 commonly used algorithms (area under the receiver operating characteristic curve range = 0.54-0.99). Application of BayPR to expertly curated variants in 8 genes associated with 7 Mendelian conditions led to the assignment of a disease-causing probability of ≥80% to 1350 of 1374 (98.3%) pathogenic/likely pathogenic variants and of ≤20% to 22 of 23 (95.7%) benign/likely benign variants. CONCLUSION Irrespective of the variant type or functional effect, the BayPR approach provides probabilities of pathogenicity for DNA variants responsible for Mendelian disorders using only the variant counts in affected and unaffected population samples.
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Affiliation(s)
- Joseph M Collaco
- Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Karen S Raraigh
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Joshua Betz
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Melis Atalar Aksit
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital Zürich, Zürich, Switzerland
| | - Jordan Brown
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Harry C Dietz
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Howard Hughes Medical Institute, Chevy Chase, MD
| | - Gretchen MacCarrick
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lawrence M Nogee
- Eudowood Neonatal Pulmonary Division, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Molly B Sheridan
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Hilary J Vernon
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Terri H Beaty
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Thomas A Louis
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Garry R Cutting
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
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21
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Byeon SK, Ramarajan MG, Madugundu AK, Oglesbee D, Vernon HJ, Pandey A. High-resolution mass spectrometric analysis of cardiolipin profiles in Barth syndrome. Mitochondrion 2021; 60:27-32. [PMID: 34273557 DOI: 10.1016/j.mito.2021.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/16/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022]
Abstract
Barth syndrome is an X-linked recessive disorder caused by pathogenic variants in TAZ, which leads to a reduction in cardiolipin with a concomitant elevation of monolysocardiolipins. There is a paucity of studies characterizing changes in individual species of monolysocardiolipins, dilysocardiolipins and cardiolipin in Barth syndrome using high resolution untargeted lipidomics that can accurately annotate and quantify diverse lipids. We confirmed the structural diversity monolysocardiolipins, dilysocardiolipins and cardiolipin and identified individual species that showed previously unreported alterations in BTHS. Development of mass spectrometry-based targeted assays for these lipid biomarkers should provide an important tool for clinical diagnosis of Barth syndrome.
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Affiliation(s)
- Seul Kee Byeon
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Madan Gopal Ramarajan
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States; Institute of Bioinformatics, International Technology Park, Bangalore, India; Manipal Academy of Higher Education, Manipal, India
| | - Anil K Madugundu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States; Institute of Bioinformatics, International Technology Park, Bangalore, India; Manipal Academy of Higher Education, Manipal, India; Center for Molecular Medicine, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Devin Oglesbee
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Akhilesh Pandey
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States; Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States.
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22
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Li Y, Godown J, Taylor CL, Dipchand AI, Bowen VM, Feingold B. Favorable outcomes after heart transplantation in Barth syndrome. J Heart Lung Transplant 2021; 40:1191-1198. [PMID: 34330606 DOI: 10.1016/j.healun.2021.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 05/26/2021] [Accepted: 06/30/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Barth Syndrome (BTHS) is a rare, X-linked disease characterized by cardioskeletal myopathy and neutropenia. Comparative outcomes after heart transplantation have not been reported. METHODS We identified BTHS recipients across 3 registries (Pediatric Heart Transplant Study Registry [PHTS], Barth Syndrome Research Registry and Repository, and Scientific Registry of Transplant Recipient-Pediatric Health Information System) and matched them 1:4 to non-BTHS, male heart transplant (HT) recipients listed with dilated cardiomyopathy in PHTS. Demographics and survival data were analyzed for all recipients, whereas post-HT infection, malignancy, allograft vasculopathy, and acute rejection were only available for analysis for individuals with PHTS data. RESULTS Forty-seven BTHS individuals with 51 listings and 43 HTs (including 2 re-transplants) were identified. Age at primary HT was 1.7 years (IQR: 0.6-4.5). Mechanical circulatory support at HT was common (ventricular assist device 29%, extracorporeal membrane oxygenation 5%). Over a median follow-up of 4.5 years (IQR 2.7-9.1), survival for BTHS HT recipients was no different than non-BTHS HT recipients (HR 0.91, 95% CI 0.40-2.12, p = 0.85). Among those with PHTS data (n = 28), BTHS HT recipients showed no difference in freedom from infection (HR 0.64, 0.34-1.22; p = 0.18), malignancy (HR 0.22, 0.02-2.01, p = 0.18), and allograft vasculopathy (HR 0.58, 0.16-2.1, p = 0.41). Freedom from acute rejection (HR 0.39, 0.17-0.86, p = 0.02) was greater for BTHS HT recipients despite similar use of induction (61 vs 73%, p = 0.20), steroids at 30-days (75 vs 62%, p = 0.27), and dual/triple drug immunosuppression at 1-year (80 vs 84%, p = 0.55). CONCLUSIONS In this largest cohort yet reported, individuals with BTHS have equivalent survival with less acute rejection and no difference in infection or malignancy after HT. When indicated, HT for individuals with BTHS is appropriate.
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Affiliation(s)
- Yu Li
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Justin Godown
- Division of Pediatric Cardiology, Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Carolyn L Taylor
- Division of Cardiology, Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina
| | - Anne I Dipchand
- Division of Cardiology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | | | - Brian Feingold
- Departments of Pediatrics and Clinical and Translational Science, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
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23
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Olivar-Villanueva M, Ren M, Phoon CKL. Neurological & psychological aspects of Barth syndrome: Clinical manifestations and potential pathogenic mechanisms. Mitochondrion 2021; 61:188-195. [PMID: 34197965 DOI: 10.1016/j.mito.2021.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023]
Abstract
Barth syndrome is a rare X-linked multisystem mitochondrial disease that is caused by variants in the tafazzin gene leading to deficient and abnormal cardiolipin. Previous research has focused on the cardiomyopathy and neutropenia in individuals with Barth syndrome, yet just as common are the least explored neurological aspects of Barth syndrome. This review focuses on the major neuropsychological and neurophysiological phenotypes that affect the quality of life of individuals with Barth syndrome, including difficulties in sensory perception and feeding, fatigue, and cognitive and psychological challenges. We propose selected pathogenetic mechanisms underlying these phenotypes and draw parallels to other relevant disorders. Finally, avenues for future research are also suggested.
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Affiliation(s)
- Melissa Olivar-Villanueva
- Departments of Pediatrics, New York University Grossman School of Medicine, New York, NY, United States
| | - Mindong Ren
- Departments of Anesthesiology, New York University Grossman School of Medicine, New York, NY, United States; Departments of Cell Biology, New York University Grossman School of Medicine, New York, NY, United States
| | - Colin K L Phoon
- Departments of Pediatrics, New York University Grossman School of Medicine, New York, NY, United States.
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Falabella M, Vernon HJ, Hanna MG, Claypool SM, Pitceathly RDS. Cardiolipin, Mitochondria, and Neurological Disease. Trends Endocrinol Metab 2021; 32:224-237. [PMID: 33640250 PMCID: PMC8277580 DOI: 10.1016/j.tem.2021.01.006] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 02/07/2023]
Abstract
Over the past decade, it has become clear that lipid homeostasis is central to cellular metabolism. Lipids are particularly abundant in the central nervous system (CNS) where they modulate membrane fluidity, electric signal transduction, and synaptic stabilization. Abnormal lipid profiles reported in Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and traumatic brain injury (TBI), are further support for the importance of lipid metablism in the nervous system. Cardiolipin (CL), a mitochondria-exclusive phospholipid, has recently emerged as a focus of neurodegenerative disease research. Aberrant CL content, structure, and localization are linked to impaired neurogenesis and neuronal dysfunction, contributing to aging and the pathogenesis of several neurodegenerative diseases, such as AD and PD. Furthermore, the highly tissue-specific acyl chain composition of CL confers it significant potential as a biomarker to diagnose and monitor the progression in several neurological diseases. CL also represents a potential target for pharmacological strategies aimed at treating neurodegeneration. Given the equipoise that currently exists between CL metabolism, mitochondrial function, and neurological disease, we review the role of CL in nervous system physiology and monogenic and neurodegenerative disease pathophysiology, in addition to its potential application as a biomarker and pharmacological target.
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Affiliation(s)
- Micol Falabella
- Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology, London, UK
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael G Hanna
- Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK.
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Abstract
PURPOSE OF REVIEW Human reproduction is remarkably inefficient; with pregnancy loss occurring in 10-30% of clinically recognized pregnancies. Of those, 3-5% of couples experience recurrent pregnancy loss (RPL), more than 50% of who never receive an underlying diagnosis. Herein, we review evidence that genetic changes, including pathogenic variant(s) in highly penetrant genes, may provide an explanation for a proportion of couples with pregnancy loss. RECENT FINDINGS Genetic abnormalities that may predispose to pregnancy loss include chromosomal aneuploidy, copy number variants, single-gene changes and others. Although previously limited by the need for hypothesis-driven assessment, advancement of various molecular technologies have sheparded in the opportunity to identify molecular cause of highly heterogeneous conditions, including RPL. The identification of causative genetic aberrations associated with RPL demonstrates a promising area of further research. SUMMARY The journey of human development from a single-cell zygote to a term infant is complex process. Early research into copy number variants and highly penetrant single-gene changes may provide diagnosis for a proportion of couples with RPL as well as inform genes critical for early human development.
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Affiliation(s)
- Christina G Tise
- Division of Medical Genetics, Department of Pediatrics, Stanford University, Stanford, California, USA
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