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Larson AA, Balasubramaniam S, Christodoulou J, Burrage LC, Marom R, Graham BH, Diaz GA, Glamuzina E, Hauser N, Heese B, Horvath G, Mattman A, van Karnebeek C, Lane Rutledge S, Williamson A, Estrella L, Van Hove JKL, Weisfeld-Adams JD. Biochemical signatures mimicking multiple carboxylase deficiency in children with mutations in MT-ATP6. Mitochondrion 2018; 44:58-64. [PMID: 29307858 DOI: 10.1016/j.mito.2018.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 11/21/2017] [Accepted: 01/03/2018] [Indexed: 12/13/2022]
Abstract
Elevations of specific acylcarnitines in blood reflect carboxylase deficiencies, and have utility in newborn screening for life-threatening organic acidemias and other inherited metabolic diseases. In this report, we describe a newly-identified association of biochemical features of multiple carboxylase deficiency in individuals harboring mitochondrial DNA (mtDNA) mutations in MT-ATP6 and in whom organic acidemias and multiple carboxylase deficiencies were excluded. Using retrospective chart review, we identified eleven individuals with abnormally elevated propionylcarnitine (C3) or hydroxyisovalerylcarnitine (C5OH) with mutations in MT-ATP6, most commonly m.8993T>G in high heteroplasmy or homoplasmy. Most patients were ascertained on newborn screening; most had normal enzymatic or molecular genetic testing to exclude biotinidase and holocarboxylase synthetase deficiencies. MT-ATP6 is associated with some cases of Leigh disease; clinical outcomes in our cohort ranged from death from neurodegenerative disease in early childhood to clinically and developmentally normal after several years of follow-up. These cases expand the biochemical phenotype associated with MT-ATP6 mutations, especially m.8993T>G, to include acylcarnitine abnormalities mimicking carboxylase deficiency states. Clinicians should be aware of this association and its implications for newborn screening, and consider mtDNA sequencing in patients exhibiting similar acylcarnitine abnormalities that are biotin-unresponsive and in whom other enzymatic deficiencies have been excluded.
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Affiliation(s)
- Austin A Larson
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA; Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, CO, USA.
| | - Shanti Balasubramaniam
- Princess Margaret Hospital for Children, Perth, Australia; Children's Hospital at Westmead, Sydney, Australia
| | - John Christodoulou
- Neurodevelopmental Genomics Research Group, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - George A Diaz
- Program for Inherited Metabolic Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Emma Glamuzina
- Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
| | - Natalie Hauser
- Inherited Metabolic Diseases Clinic, Valley Children's Hospital, Madera, CA, USA
| | - Bryce Heese
- Children's Mercy Hospitals and Clinics, Kansas City, MO, USA
| | - Gabriella Horvath
- Inherited Metabolic Diseases Clinic, University of British Columbia, Vancouver, Canada
| | - Andre Mattman
- Inherited Metabolic Diseases Clinic, University of British Columbia, Vancouver, Canada
| | - Clara van Karnebeek
- Inherited Metabolic Diseases Clinic, University of British Columbia, Vancouver, Canada; Centre for Molecular Medicine and Therapeutics, Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - S Lane Rutledge
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Amy Williamson
- Program for Inherited Metabolic Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lissette Estrella
- Program for Inherited Metabolic Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Johan K L Van Hove
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA; Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, CO, USA
| | - James D Weisfeld-Adams
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA; Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, CO, USA
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van Karnebeek CDM, Stockler-Ipsiroglu S, Jaggumantri S, Assmann B, Baxter P, Buhas D, Bok LA, Cheng B, Coughlin CR, Das AM, Giezen A, Al-Hertani W, Ho G, Meyer U, Mills P, Plecko B, Struys E, Ueda K, Albersen M, Verhoeven N, Gospe SM, Gallagher RC, Van Hove JKL, Hartmann H. Lysine-Restricted Diet as Adjunct Therapy for Pyridoxine-Dependent Epilepsy: The PDE Consortium Consensus Recommendations. JIMD Rep 2014; 15:1-11. [PMID: 24748525 DOI: 10.1007/8904_2014_296] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/21/2014] [Accepted: 01/28/2014] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Seventy-five percent of patients with pyridoxine-dependent epilepsy (PDE) due to Antiquitin (ATQ) deficiency suffer from developmental delay and/or intellectual disability (IQ < 70) despite seizure control. An observational study showed that adjunct treatment with a lysine-restricted diet is safe, results in partial normalization of lysine intermediates in body fluids, and may have beneficial effects on seizure control and psychomotor development. METHODS In analogy to the NICE guideline process, the international PDE Consortium, an open platform uniting scientists and clinicians working in the field of this metabolic epilepsy, during four workshops (2010-2013) developed a recommendation for a lysine-restricted diet in PDE, with the aim of standardizing its implementation and monitoring of patients. Additionally, a proposal for a further observational study is suggested. RESULTS (1) All patients with confirmed ATQ deficiency are eligible for adjunct treatment with lysine-restricted diet, unless treatment with pyridoxine alone has resulted in complete symptom resolution, including normal behavior and development. (2) Lysine restriction should be started as early as possible; the optimal duration remains undetermined. (3) The diet should be implemented and the patient be monitored according to these recommendations in order to assure best possible quality of care and safety. DISCUSSION The implementation of this recommendation will provide a unique and a much needed opportunity to gather data with which to refine the recommendation as well as improve our understanding of outcomes of individuals affected by this rare disease. We therefore propose an international observational study that would utilize freely accessible, online data sharing technologies to generate more evidence.
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Affiliation(s)
- Clara D M van Karnebeek
- Centre for Molecular Medicine and Therapeutics, 3091-950 West 28th Avenue, Vancouver, Canada, V5Z 4H4,
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