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Burda P, Hlavackova A, Polivkova V, Curik N, Laznicka A, Krizkova J, Suttnar J, Klener P, Polakova KM. Imatinib therapy of chronic myeloid leukemia significantly reduces carnitine cell intake, resulting in adverse events. Mol Metab 2024; 88:102016. [PMID: 39182842 PMCID: PMC11403060 DOI: 10.1016/j.molmet.2024.102016] [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: 06/18/2024] [Revised: 08/08/2024] [Accepted: 08/19/2024] [Indexed: 08/27/2024] Open
Abstract
OBJECTIVE A prominent, safe and efficient therapy for patients with chronic myeloid leukemia (CML) is inhibiting oncogenic protein BCR::ABL1 in a targeted manner with imatinib, a tyrosine kinase inhibitor. A substantial part of patients treated with imatinib report skeletomuscular adverse events affecting their quality of life. OCTN2 membrane transporter is involved in imatinib transportation into the cells. At the same time, the crucial physiological role of OCTN2 is cellular uptake of carnitine which is an essential co-factor for the mitochondrial β-oxidation pathway. This work investigates the impact of imatinib treatment on carnitine intake and energy metabolism of muscle cells. METHODS HTB-153 (human rhabdomyosarcoma) cell line and KCL-22 (CML cell line) were used to study the impact of imatinib treatment on intracellular levels of carnitine and vice versa. The energy metabolism changes in cells treated by imatinib were quantified and compared to changes in cells exposed to highly specific OCTN2 inhibitor vinorelbine. Mouse models were used to test whether in vitro observations are also achieved in vivo in thigh muscle tissue. The analytes of interest were quantified using a Prominence HPLC system coupled with a tandem mass spectrometer. RESULTS This work showed that through the carnitine-specific transporter OCTN2, imatinib and carnitine intake competed unequally and intracellular carnitine concentrations were significantly reduced. In contrast, carnitine preincubation did not influence imatinib cell intake or interfere with leukemia cell targeting. Blocking the intracellular supply of carnitine with imatinib significantly reduced the production of most Krebs cycle metabolites and ATP. However, subsequent carnitine supplementation rescued mitochondrial energy production. Due to specific inhibition of OCTN2 activity, the influx of carnitine was blocked and mitochondrial energy metabolism was impaired in muscle cells in vitro and in thigh muscle tissue in a mouse model. CONCLUSIONS This preclinical experimental study revealed detrimental effect of imatinib on carnitine-mediated energy metabolism of muscle cells providing a possible molecular background of the frequently occurred side effects during imatinib therapy such as fatigue, muscle pain and cramps.
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Affiliation(s)
- Pavel Burda
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic; Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Vendula Polivkova
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic
| | - Nikola Curik
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic; Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Adam Laznicka
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic; Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jitka Krizkova
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic
| | - Jiri Suttnar
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic
| | - Pavel Klener
- Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic; First Medical Department- Dept. of Hematology, First Faculty of Medicine and General University Hospital, Charles University, Prague, Czech Republic
| | - Katerina Machova Polakova
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic; Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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2
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Pochini L, Galluccio M, Console L, Scalise M, Eberini I, Indiveri C. Inflammation and Organic Cation Transporters Novel (OCTNs). Biomolecules 2024; 14:392. [PMID: 38672410 PMCID: PMC11048549 DOI: 10.3390/biom14040392] [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: 02/15/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/28/2024] Open
Abstract
Inflammation is a physiological condition characterized by a complex interplay between different cells handled by metabolites and specific inflammatory-related molecules. In some pathological situations, inflammation persists underlying and worsening the pathological state. Over the years, two membrane transporters namely OCTN1 (SLC22A4) and OCTN2 (SLC22A5) have been shown to play specific roles in inflammation. These transporters form the OCTN subfamily within the larger SLC22 family. The link between these proteins and inflammation has been proposed based on their link to some chronic inflammatory diseases such as asthma, Crohn's disease (CD), and rheumatoid arthritis (RA). Moreover, the two transporters show the ability to mediate the transport of several compounds including carnitine, carnitine derivatives, acetylcholine, ergothioneine, and gut microbiota by-products, which have been specifically associated with inflammation for their anti- or proinflammatory action. Therefore, the absorption and distribution of these molecules rely on the presence of OCTN1 and OCTN2, whose expression is modulated by inflammatory cytokines and transcription factors typically activated by inflammation. In the present review, we wish to provide a state of the art on OCTN1 and OCTN2 transport function and regulation in relationships with inflammation and inflammatory diseases focusing on the metabolic signature collected in different body districts and gene polymorphisms related to inflammatory diseases.
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Affiliation(s)
- Lorena Pochini
- Laboratory of Biochemistry, Molecular Biotechnology and Molecular Biology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (M.G.); (L.C.); (M.S.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Michele Galluccio
- Laboratory of Biochemistry, Molecular Biotechnology and Molecular Biology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (M.G.); (L.C.); (M.S.)
| | - Lara Console
- Laboratory of Biochemistry, Molecular Biotechnology and Molecular Biology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (M.G.); (L.C.); (M.S.)
| | - Mariafrancesca Scalise
- Laboratory of Biochemistry, Molecular Biotechnology and Molecular Biology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (M.G.); (L.C.); (M.S.)
| | - Ivano Eberini
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy;
| | - Cesare Indiveri
- Laboratory of Biochemistry, Molecular Biotechnology and Molecular Biology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; (M.G.); (L.C.); (M.S.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
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3
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Jolfayi AG, Naderi N, Ghasemi S, Salmanipour A, Adimi S, Maleki M, Kalayinia S. A novel pathogenic variant in the carnitine transporter gene, SLC22A5, in association with metabolic carnitine deficiency and cardiomyopathy features. BMC Cardiovasc Disord 2024; 24:1. [PMID: 38166572 PMCID: PMC10763261 DOI: 10.1186/s12872-023-03676-z] [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: 04/26/2023] [Accepted: 12/15/2023] [Indexed: 01/04/2024] Open
Abstract
BACKGROUND Primary carnitine deficiency (PCD) denotes low carnitine levels with an autosomal recessive pattern of inheritance. Cardiomyopathy is the most common cardiac symptom in patients with PCD, and early diagnosis can prevent complications. Next-generation sequencing can identify genetic variants attributable to PCD efficiently. OBJECTIVE We aimed to detect the genetic cause of the early manifestations of hypertrophic cardiomyopathy and metabolic abnormalities in an Iranian family. METHODS We herein describe an 8-year-old boy with symptoms of weakness and lethargy diagnosed with PCD through clinical evaluations, lab tests, echocardiography, and cardiac magnetic resonance imaging. The candidate variant was confirmed through whole-exome sequencing, polymerase chain reaction, and direct Sanger sequencing. The binding efficacy of normal and mutant protein-ligand complexes were evaluated via structural modeling and docking studies. RESULTS Clinical evaluations, echocardiography, and cardiac magnetic resonance imaging findings revealed hypertrophic cardiomyopathy as a clinical presentation of PCD. Whole-exome sequencing identified a new homozygous variant, SLC22A5 (NM_003060.4), c.821G > A: p.Trp274Ter, associated with carnitine transport. Docking analysis highlighted the impact of the variant on carnitine transport, further indicating its potential role in PCD development. CONCLUSIONS The c.821G > A: p.Trp274Ter variant in SLC22A5 potentially acted as a pathogenic factor by reducing the binding affinity of organic carnitine transporter type 2 proteins for carnitine. So, the c.821G > A variant may be associated with carnitine deficiency, metabolic abnormalities, and cardiomyopathic characteristics.
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Affiliation(s)
- Amir Ghaffari Jolfayi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Niloofar Naderi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Serwa Ghasemi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Alireza Salmanipour
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Sara Adimi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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4
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Ji X, Ge Y, Ni Q, Xu S, Xiong Z, Yang L, Hu L, Cao Y, Lu Y, Wei Q, Kang W, Zhuang D, Zhou W, Dong X. Primary carnitine deficiency: Estimation of prevalence in Chinese population and insights into newborn screening. Front Genet 2023; 14:1304458. [PMID: 38125748 PMCID: PMC10730660 DOI: 10.3389/fgene.2023.1304458] [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: 09/29/2023] [Accepted: 11/17/2023] [Indexed: 12/23/2023] Open
Abstract
Primary carnitine deficiency (PCD) caused by pathogenic variants in the solute carrier family 22 member 5 (SLC22A5) gene is a rare autosomal recessive disease that results in defective fatty acid oxidation. PCD can be detected through tandem mass spectrometry (MS/MS), but transplacental transport of free carnitine from mothers may cause false negatives or positives during newborn screening (NBS). This study aimed to analyze the genetic characteristics of SLC22A5 and estimate the prevalence of PCD in the Chinese population, providing useful information for NBS and genetic counseling. We manually curated SLC22A5 pathogenic or likely pathogenic (P/LP) variants according to the American College of Medical Genetics and Genomics (ACMG) guidelines and identified 128 P/LP variants. Based on the China Neonatal Genomes Project (CNGP), the estimated PCD prevalence was 1:17,456, which was higher than that in other populations. The genotype-phenotype association analysis showed that patients carrying homozygous c.760C>T and c.844C>T were more likely to present cardiomyopathy, whereas those carrying homozygous c.1400C>G were more likely to be asymptomatic (all p-values < 0.05). We found that there was no significant difference in initial C0 concentrations between patients and carriers, but there was a significant difference in the second-tier screening of C0 concentration between them (p-value < 0.05). We established a cost-effective variant panel containing 10 high-frequency sites and developed a screening algorithm incorporating gene panels with MS/MS, which could rescue one more patient who was undetected from MS/MS. In conclusion, the prevalence of PCD in the Chinese population is relatively high. The combination of conventional NBS with genetic sequencing is suggested for early diagnosis of PCD.
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Affiliation(s)
- Xiaoshan Ji
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
- Division of Neonatology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
| | - Yanzhuang Ge
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Qi Ni
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Suhua Xu
- Children’s Hospital of Shanghai, Shanghai, China
| | - Zhongmeng Xiong
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
- Division of Neonatology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
| | - Lin Yang
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Liyuan Hu
- Division of Neonatology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
| | - Yun Cao
- Division of Neonatology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
| | - Yulan Lu
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Qiufen Wei
- Division of Neonatology, Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Wenqing Kang
- Division of Neonatology, Children’s Hospital Affiliated to Zhengzhou University, Zhengzhou, China
| | - Deyi Zhuang
- Division of Pediatrics, Xiamen Children’s Hospital, Xiamen, China
| | - Wenhao Zhou
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
- Division of Neonatology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Xinran Dong
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
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Crefcoeur L, Ferdinandusse S, van der Crabben SN, Dekkers E, Fuchs SA, Huidekoper H, Janssen M, Langendonk J, Maase R, de Sain M, Rubio E, van Spronsen FJ, Vaz FM, Verschoof R, de Vries M, Wijburg F, Visser G, Langeveld M. Newborn screening for primary carnitine deficiency: who will benefit? - a retrospective cohort study. J Med Genet 2023; 60:1177-1185. [PMID: 37487700 DOI: 10.1136/jmg-2023-109206] [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: 02/26/2023] [Accepted: 06/17/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND Newborn screening (NBS) programmes identify a wide range of disease phenotypes, which raises the question whether early identification and treatment is beneficial for all. This study aims to answer this question for primary carnitine deficiency (PCD) taking into account that NBS for PCD identifies newborns with PCD and also until then undiagnosed mothers. METHODS We investigated clinical, genetic (variants in SLC22A5 gene) and functional (carnitine transport activity in fibroblasts) characteristics of all referred individuals through NBS (newborns and mothers) and clinically diagnosed patients with PCD (not through NBS). Disease phenotype in newborns was predicted using data from PCD mothers and cases published in literature with identical SLC22A5 variants. RESULTS PCD was confirmed in 19/131 referred newborns, 37/82 referred mothers and 5 clinically diagnosed patients. Severe symptoms were observed in all clinically diagnosed patients, 1 newborn and none of the mothers identified by NBS. PCD was classified as severe in all 5 clinically diagnosed patients, 3/19 newborns and 1/37 mothers; as benign in 8/19 newborns and 36/37 mothers and as unknown in 8/19 newborns. Carnitine transport activity completely separated severe phenotype from benign phenotype (median (range): 4.0% (3.5-5.0)] vs 26% (9.5-42.5), respectively). CONCLUSION The majority of mothers and a significant proportion of newborns with PCD identified through NBS are likely to remain asymptomatic without early treatment. Conversely, a small proportion of newborns with predicted severe PCD could greatly benefit from early treatment. Genetic variants and carnitine transport activity can be used to distinguish between these groups.
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Affiliation(s)
- Loek Crefcoeur
- Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
- Department of Pediatrics, Division of Metabolic Disorders, Amsterdam UMC Locatie AMC, Amsterdam, The Netherlands
- Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam UMC Locatie Meibergdreef, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Department of Pediatrics, Division of Metabolic Disorders, Amsterdam UMC Locatie AMC, Amsterdam, The Netherlands
- Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam UMC Locatie Meibergdreef, Amsterdam, The Netherlands
| | - Saskia N van der Crabben
- Human Genetics, Amsterdam UMC Locatie Meibergdreef, Amsterdam, The Netherlands
- United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Eugènie Dekkers
- Centre for Population Screening, RIVM, Bilthoven, The Netherlands
| | - Sabine A Fuchs
- Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
| | - Hidde Huidekoper
- Department of Pediatrics, Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Mirian Janssen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Janneke Langendonk
- Department of Internal Medicine, Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Rose Maase
- Department of Biologicals, Screening and Innovation, RIVM, Bilthoven, The Netherlands
| | - Monique de Sain
- Section Metabolic Diagnostics, Department of Genetics, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
| | - Estela Rubio
- Department of Pediatrics/Laboratory of Clinical Genetics, Maastricht UMC+, Maastricht, The Netherlands
| | - Francjan J van Spronsen
- Section of Metabolic Diseases, University Medical Centre Groningen, Beatrix Children's Hospital, Groningen, The Netherlands
| | - Frédéric Maxime Vaz
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Departments of Clinical Chemistry and Pediatrics, Core Facility Metabolomics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam UMC Locatie Meibergdreef, Amsterdam, The Netherlands
| | - Rendelien Verschoof
- Department for Vaccine Supply and Prevention Programs, RIVM, Bilthoven, The Netherlands
| | - Maaike de Vries
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frits Wijburg
- Department of Pediatrics, Division of Metabolic Disorders, Amsterdam UMC Locatie AMC, Amsterdam, The Netherlands
| | - Gepke Visser
- Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
- Department of Pediatrics, Division of Metabolic Disorders, Amsterdam UMC Locatie AMC, Amsterdam, The Netherlands
| | - Mirjam Langeveld
- Department of Endocrinology and Metabolism, Amsterdam UMC Locatie Meibergdreef, Amsterdam, The Netherlands
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6
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Hanington OP, Armstrong C, Pierre G, Stuart G, Hancox JC. Left ventricular noncompaction cardiomyopathy and short QT syndrome due to primary carnitine deficiency. Ann Noninvasive Electrocardiol 2023; 28:e13077. [PMID: 37658577 PMCID: PMC10646383 DOI: 10.1111/anec.13077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/06/2023] [Accepted: 07/26/2023] [Indexed: 09/03/2023] Open
Abstract
We report the case of a 13-year-old female patient presenting with presyncope and palpitations. Her electrocardiogram revealed an abbreviation of the rate-corrected QT interval with imaging showing significant left ventricular dysfunction. Carnitine levels were measured as part of her diagnostic workup, discovering a rare, reversible cause of short QT syndrome (SQTS) and associated cardiomyopathy-primary carnitine deficiency (PCD) caused by a homozygous mutation in the SLC22A5 gene, leading to an in-frame deletion mutation (NP_003051.1:p.Phe23del) affecting the organic cation transporter 2 (OCTN2) protein. Following the treatment with oral carnitine supplementation, her QT interval returned to within the normal range with significant improvement in left ventricular function.
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Affiliation(s)
- Oliver P. Hanington
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | | | | | - Graham Stuart
- Bristol Heart InstituteBristolUK
- Bristol Royal Hospital for Sick ChildrenBristolUK
| | - Jules C. Hancox
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
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7
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Maier EM, Mütze U, Janzen N, Steuerwald U, Nennstiel U, Odenwald B, Schuhmann E, Lotz-Havla AS, Weiss KJ, Hammersen J, Weigel C, Thimm E, Grünert SC, Hennermann JB, Freisinger P, Krämer J, Das AM, Illsinger S, Gramer G, Fang-Hoffmann J, Garbade SF, Okun JG, Hoffmann GF, Kölker S, Röschinger W. Collaborative evaluation study on 18 candidate diseases for newborn screening in 1.77 million samples. J Inherit Metab Dis 2023; 46:1043-1062. [PMID: 37603033 DOI: 10.1002/jimd.12671] [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: 05/06/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 08/22/2023]
Abstract
Analytical and therapeutic innovations led to a continuous but variable extension of newborn screening (NBS) programmes worldwide. Every extension requires a careful evaluation of feasibility, diagnostic (process) quality and possible health benefits to balance benefits and limitations. The aim of this study was to evaluate the suitability of 18 candidate diseases for inclusion in NBS programmes. Utilising tandem mass spectrometry as well as establishing specific diagnostic pathways with second-tier analyses, three German NBS centres designed and conducted an evaluation study for 18 candidate diseases, all of them inherited metabolic diseases. In total, 1 777 264 NBS samples were analysed. Overall, 441 positive NBS results were reported resulting in 68 confirmed diagnoses, 373 false-positive cases and an estimated cumulative prevalence of approximately 1 in 26 000 newborns. The positive predictive value ranged from 0.07 (carnitine transporter defect) to 0.67 (HMG-CoA lyase deficiency). Three individuals were missed and 14 individuals (21%) developed symptoms before the positive NBS results were reported. The majority of tested candidate diseases were found to be suitable for inclusion in NBS programmes, while multiple acyl-CoA dehydrogenase deficiency, isolated methylmalonic acidurias, propionic acidemia and malonyl-CoA decarboxylase deficiency showed some and carnitine transporter defect significant limitations. Evaluation studies are an important tool to assess the potential benefits and limitations of expanding NBS programmes to new diseases.
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Affiliation(s)
- Esther M Maier
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Munich, Germany
| | - Ulrike Mütze
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Nils Janzen
- Screening-Labor Hanover, Hanover, Germany
- Department of Clinical Chemistry, Hanover Medical School, Hanover, Germany
- Division of Laboratory Medicine, Centre for Children and Adolescents, Kinder- und Jugendkrankenhaus Auf der Bult, Hanover, Germany
| | | | - Uta Nennstiel
- Bavarian Health and Food Safety Authority, Oberschleissheim, Germany
| | - Birgit Odenwald
- Bavarian Health and Food Safety Authority, Oberschleissheim, Germany
| | | | - Amelie S Lotz-Havla
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Munich, Germany
| | - Katharina J Weiss
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Munich, Germany
| | - Johanna Hammersen
- Department of Pediatrics, Division of Inborn Errors of Metabolism, University Hospital Erlangen, Erlangen, Germany
| | - Corina Weigel
- Department of Pediatrics, Division of Inborn Errors of Metabolism, University Hospital Erlangen, Erlangen, Germany
| | - Eva Thimm
- Department of General Pediatrics, University Children's Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sarah C Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Centre-University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Julia B Hennermann
- Villa Metabolica, Center for Pediatric and Adolescent Medicine, Mainz University Medical Center, Mainz, Germany
| | - Peter Freisinger
- Children's Hospital Reutlingen, Klinikum am Steinenberg, Reutlingen, Germany
| | - Johannes Krämer
- Department of Pediatric and Adolescent Medicine, Ulm University Medical School, Ulm, Germany
| | - Anibh M Das
- Hanover Medical School, Clinic for Pediatric Kidney-Liver- and Metabolic Diseases, Hanover, Germany
| | - Sabine Illsinger
- Hanover Medical School, Clinic for Pediatric Kidney-Liver- and Metabolic Diseases, Hanover, Germany
| | - Gwendolyn Gramer
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
- University Medical Center Hamburg-Eppendorf, University Children's Hospital, Hamburg, Germany
| | - Junmin Fang-Hoffmann
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Sven F Garbade
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Wulf Röschinger
- Laboratory Becker MVZ GbR, Newborn Screening Unit, Munich, Germany
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8
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Onuki T, Hiroshima S, Sawano K, Shibata N, Ogawa Y, Nagasaki K, Nyuzuki H. A Study of Maternal Patients Diagnosed with Inborn Errors of Metabolism Due to Positive Newborn Mass Screening in Their Newborns. CHILDREN (BASEL, SWITZERLAND) 2023; 10:1341. [PMID: 37628339 PMCID: PMC10452974 DOI: 10.3390/children10081341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/22/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023]
Abstract
BACKGROUND There are reports of mothers being diagnosed with inborn errors of metabolism (IEM) via positive newborn screening (NBS) of their newborns. Mothers with IEM are often considered to have mild cases of little pathological significance. Based in Niigata Prefecture, this study aimed to investigate mothers newly diagnosed with IEM via positive NBS in their newborns using tandem mass spectrometry, and to clarify the disease frequency and severity. METHODS This was a single-institution, population-based, retrospective study. The subjects were mothers whose newborns had false-positive NBS, among 80,410 newborns who underwent NBS between April 2016 and May 2021. RESULT there were 3 new mothers were diagnosed with IEM (2 with primary systemic carnitine deficiency (PCD) and 1 with 3-methylcrotonyl-CoA carboxylase deficiency) out of 5 who underwent examination among 18 false positives. The opportunity for diagnosis was low C0 and high C5-OH acylcarnitine levels in their newborn. Two novel SLC22A5 variants (c.1063T > C/c.1266A > G) were identified in patients with PCD. None of the patients had any complications at the time of diagnosis, but two patients showed improvement in fatigue and headache after taking oral carnitine. CONCLUSION New mothers with IEM cannot be considered as mild cases and need to be treated when necessary. The two novel SLC22A5 variants further expand the variant spectrum of PCD.
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Affiliation(s)
| | | | | | | | | | | | - Hiromi Nyuzuki
- Division of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medicine and Dental Sciences, Niigata 951-8510, Japan; (T.O.); (S.H.); (K.S.); (N.S.); (Y.O.); (K.N.)
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9
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Shi C, Ao Z, Liu B, Xiao X, Gu X, Yang Q, Hao H, Cai Y, Li S. Increased acylcarnitine ratio indices in newborn screening for carnitine-acylcarnitine translocase deficiency shows increased sensitivity and reduced false-positivity. Transl Pediatr 2023; 12:871-881. [PMID: 37305732 PMCID: PMC10248924 DOI: 10.21037/tp-22-468] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/15/2023] [Indexed: 06/13/2023] Open
Abstract
Background Carnitine-acylcarnitine translocase (CACT) deficiency is a rare autosomal recessive metabolic disorder of mitochondrial long-chain fatty acid oxidation. Newborn screening via tandem mass spectrometry (MS/MS) technology enables early diagnosis. However, previous analyses of MS/MS data of patients showed that some results were misdiagnosed because they did not show typical acylcarnitine profiles of CACT deficiency. This study aimed to identify additional indices to assist the diagnosis of CACT deficiency. Methods To evaluate the acylcarnitine profile and the acylcarnitine ratios of individuals with CACT deficiency, the MS/MS data of 15 patients diagnosed via genetic testing were retrospectively analysed. The sensitivity and false-positive rates of primary acylcarnitine markers and ratio indices were validated using the data from 28,261 newborns and 53 false-positive cases. Additionally, the MS/MS data of 20 newborns carrying the c.199-10T>G mutation in SLC25A20 and 40 normal controls were compared to verify whether the carriers had abnormal acylcarnitine concentrations. Results The acylcarnitine profiles from 15 patients were classified into three categories using C12, C14, C16, C18, C16:1, C18:1, and C18:2 as the primary diagnostic markers. The first category represented a typical profile (P1-P6). The second category for patients P7 and P8 showed a significant decrease in the C0 level and a normal concentration of long-chain acylcarnitines. The third category for patients P9-P15 showed the presence of interfering acylcarnitines. The second and third categories may have been misdiagnosed. An acylcarnitine ratio analysis showed that C14/C3, C16/C2, C16/C3, C18/C3, C16:1/C3, and C16:1-OH/C3 were significantly increased in all 15 patients. The verification of 28,261 newborn screening results showed that the false-positive rate of ratios, except for (C16 + C18)/C0, was lower than that of acylcarnitine indices (0.02-0.08% vs. 0.16-0.88%). None of the single long-chain acylcarnitines could separate patients from the false-positive cases; however, all ratios produced good discrimination between the two groups. Conclusions Based on the primary acylcarnitine markers alone, CACT deficiency can be misdiagnosed in newborn screening. The ratios of the primary markers (C16 + C18:1)/C2, C16/C2, C16:1/C3, and C16:1-OH/C3 can facilitate the diagnosis of CACT deficiency, thereby increasing sensitivity and reducing false-positivity.
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Affiliation(s)
- Congcong Shi
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhenzhen Ao
- Department of Neonatology, Maternal and Child Health Hospital of Heyuan City in Guangdong Province, Heyuan, China
| | - Bingqing Liu
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xin Xiao
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xia Gu
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Qiuping Yang
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hu Hao
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yao Cai
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Sitao Li
- Inborn Errors of Metabolism Laboratory, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Pediatrics, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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10
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Jia A, Lei Y, Liu DP, Pan L, Guan HZ, Yang B. A Retrospective Analysis of Clinically Focused Exome Sequencing Results of 372 Infants with Suspected Monogenic Disorders in China. Pharmgenomics Pers Med 2023; 16:81-97. [PMID: 36755623 PMCID: PMC9901461 DOI: 10.2147/pgpm.s387767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 01/12/2023] [Indexed: 02/04/2023] Open
Abstract
Objective The context was designed to optimize the diagnostic utility of clinically focused exome sequencing (CFES) and shorten the diagnostic odyssey among pediatric patients suspected of monogenic disorders (MDs). Methods Here, we retrospectively analyzed the clinical notes of 372 patients from different areas in the Jiangxi province that were referred for a diagnostic CFES and analysis from June 2018 to March 2022 with symptoms suggestive of MDs. In our study, preliminary tests using the proband-only clinical exome sequencing as a cost-effective first-tier diagnostic test for pediatric patients with unidentified MDs, supplemented by family segregation studies for targeted variants when indicated. Results Probands with confirmed diagnostic (CD) or likely diagnostic (LD) genetic influences accounted for 12% of all cases, whereas those with an uncertain diagnosis accounted for 48%. We also found that systemic primary carnitine deficiency (CDSP) (SLC22A5 gene) and phenylketonuria (PAH gene) were relatively more prevalent, and these patients with CDSP had the most frequent c.1400C > G variant (p.S467C) and c.51C > G variant (p. F17L) in this study. In addition, statistical analysis revealed that the estimates of diagnostic yields varied across certain phenotypic features of patients, and patients with specific phenotypic traits tended to benefit more from CFES. Conclusion The CFES may be a first-line genetic test for diagnosing young children with suspected genetic conditions, as it validates the identification of molecular genetics alterations and facilitates comprehensive medical management. Moreover, we found that infants exhibiting metabolism/homeostasis abnormalities, craniofacial /otolaryngology/ ophthalmologic abnormalities, and/or the integument were significantly more likely to receive a genetic diagnosis via CFES than infants without such features. However, due to the current study's low diagnostic yield and inherent limitations, high-quality clinical studies with larger sample sizes are still needed to provide more likely results and confirm our findings.
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Affiliation(s)
- An Jia
- Medical School, Huanghe Science and Technology College, Zhengzhou, People’s Republic of China
| | - Yi Lei
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, People’s Republic of China
| | - Dan-Ping Liu
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, People’s Republic of China
| | - Lu Pan
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, People’s Republic of China
| | - Hui-Zhen Guan
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, People’s Republic of China
| | - Bicheng Yang
- Medical School, Huanghe Science and Technology College, Zhengzhou, People’s Republic of China,Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, People’s Republic of China,Correspondence: Bicheng Yang, Jiangxi Provincial Key Laboratory of Birth Defect for Prevention and Control, Jiangxi Provincial Maternal and Child Health Hospital, Nanchang, 330006, People’s Republic of China, Tel +86 15350402147, Email
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11
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Lefèvre CR, Labarthe F, Dufour D, Moreau C, Faoucher M, Rollier P, Arnoux JB, Tardieu M, Damaj L, Bendavid C, Dessein AF, Acquaviva-Bourdain C, Cheillan D. Newborn Screening of Primary Carnitine Deficiency: An Overview of Worldwide Practices and Pitfalls to Define an Algorithm before Expansion of Newborn Screening in France. Int J Neonatal Screen 2023; 9:6. [PMID: 36810318 PMCID: PMC9944086 DOI: 10.3390/ijns9010006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/24/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Primary Carnitine Deficiency (PCD) is a fatty acid oxidation disorder that will be included in the expansion of the French newborn screening (NBS) program at the beginning of 2023. This disease is of high complexity to screen, due to its pathophysiology and wide clinical spectrum. To date, few countries screen newborns for PCD and struggle with high false positive rates. Some have even removed PCD from their screening programs. To understand the risks and pitfalls of implementing PCD to the newborn screening program, we reviewed and analyzed the literature to identify hurdles and benefits from the experiences of countries already screening this inborn error of metabolism. In this study, we therefore, present the main pitfalls encountered and a worldwide overview of current practices in PCD newborn screening. In addition, we address the optimized screening algorithm that has been determined in France for the implementation of this new condition.
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Affiliation(s)
| | - François Labarthe
- Reference Center of Inherited Metabolic Disorders, Clocheville Hospital, 37000 Tours, France
| | - Diane Dufour
- Reference Center of Inherited Metabolic Disorders, Clocheville Hospital, 37000 Tours, France
| | | | | | - Paul Rollier
- Rennes University Hospital Center, 35033 Rennes, France
| | - Jean-Baptiste Arnoux
- Reference Center for Inborn Error of Metabolism, Department of Pediatrics, Necker-Enfants Malades Hospital, APHP, 75015 Paris, France
| | - Marine Tardieu
- Reference Center of Inherited Metabolic Disorders, Clocheville Hospital, 37000 Tours, France
| | - Léna Damaj
- Rennes University Hospital Center, 35033 Rennes, France
| | | | - Anne-Frédérique Dessein
- Metabolism and Rare Disease Unit, Department of Biochemistry and Molecular Biology, Center of Biology and Pathology, Lille University Hospital Center, 59000 Lille, France
| | - Cécile Acquaviva-Bourdain
- Center for Inherited Metabolic Disorders and Neonatal Screening, East Biology and Pathology Department, Groupement Hospitalier Est (GHE), Hospices Civils de Lyon, 69500 Bron, France
| | - David Cheillan
- Center for Inherited Metabolic Disorders and Neonatal Screening, East Biology and Pathology Department, Groupement Hospitalier Est (GHE), Hospices Civils de Lyon, 69500 Bron, France
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12
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Louis L, Margaux G, Claire G, Delphine L, Sandrine R, Emmanuel R, Cécile G, Samir M, Isabelle R. Infantile primary carnitine deficiency: A severe cardiac presentation unresponsive to carnitine supplementation. JIMD Rep 2023; 64:35-41. [PMID: 36636599 PMCID: PMC9830015 DOI: 10.1002/jmd2.12346] [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: 07/21/2022] [Revised: 10/11/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022] Open
Abstract
Primary carnitine deficiency (PCD) is an inherited disease of fatty acid beta-oxidation with autosomal recessive inheritance. The disease manifests as metabolic decompensation with hypoketotic hypoglycaemia associated with cardiomyopathy, hepatomegaly, rhabdomyolysis, and seizures. Various outcomes are described from asymptomatic adults to dramatic sudden infant death syndrome cases. We present a severe case of PCD decompensation in an 18-week-old female. She presented with hypotonia, moaning, diarrhea, and vomiting at the pediatric emergency. Initially suspected as intracranial hypertension, the clinical condition evolved rapidly and caused a reversible cardiac arrest with profound hypoglycemia. Despite carnitine supplementation, she succumbed from cardiac arrhythmia and multivisceral failure 4 days after admission. The genetic analyses showed a PCD with biallelic pathogenic variants of SLC22A5 gene. The case report is notable for the severity of the cardiac damage possibly favored by maternal carnitine deficiency during pregnancy. The analysis of previously published PCD cases highlights (i) the importance of having large access to emergency biochemical tests for early therapeutic care although the disease has unpredictable severity and (ii) the fact that the clinical outcome remains unpredictable if carnitine treatment is initiated late.
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Affiliation(s)
- Lebreton Louis
- Laboratoire de BiochimiePôle de Biologie et Pathologie, CHU de BordeauxBordeauxFrance
| | | | - Guibet Claire
- Laboratoire de BiochimiePôle de Biologie et Pathologie, CHU de BordeauxBordeauxFrance
| | - Lamireau Delphine
- Hôpital Pédiatrique, Pôle Pédiatrique, CHU de BordeauxBordeauxFrance
| | - Roche Sandrine
- Hôpital Pédiatrique, Pôle Pédiatrique, CHU de BordeauxBordeauxFrance
| | - Richard Emmanuel
- Laboratoire de BiochimiePôle de Biologie et Pathologie, CHU de BordeauxBordeauxFrance
- INSERM BRIC U1312Université de BordeauxBordeauxFrance
| | - Ged Cécile
- Laboratoire de BiochimiePôle de Biologie et Pathologie, CHU de BordeauxBordeauxFrance
- INSERM BRIC U1312Université de BordeauxBordeauxFrance
| | - Mesli Samir
- Laboratoire de BiochimiePôle de Biologie et Pathologie, CHU de BordeauxBordeauxFrance
| | - Redonnet‐Vernhet Isabelle
- Laboratoire de BiochimiePôle de Biologie et Pathologie, CHU de BordeauxBordeauxFrance
- lNSERM MRGM U1211Université de BordeauxBordeauxFrance
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13
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Liammongkolkul S, Boonyawat B, Vijarnsorn C, Tim-Aroon T, Wasant P, Vatanavicharn N. Phenotypic and molecular features of Thai patients with primary carnitine deficiency. Pediatr Int 2023; 65:e15404. [PMID: 36321377 DOI: 10.1111/ped.15404] [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: 05/08/2022] [Revised: 09/13/2022] [Accepted: 09/22/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND Primary carnitine deficiency (PCD) is screened by expanded newborn screening (NBS) using tandem mass spectrometry (MS/MS) that can detect both affected neonates and mothers. This study aimed to delineate the clinical, biochemical, and molecular findings of Thai PCD patients. METHODS Expanded NBS using MS/MS was implemented in Bangkok and 146,757 neonates were screened between 2014 and 2018. PCD was screened by low free carnitine (C0) levels in dried blood spots. Plasma C0 levels and C0 clearance values were measured in neonates and their mothers with positive screening results. Clinically diagnosed cases were described. The coding regions and intron-exon boundaries of the SLC22A5 gene were sequenced in all cases with low plasma C0 levels. RESULTS There were 14 cases with confirmed PCD: two clinically diagnosed cases, and 12 cases identified through NBS including five newborns, six mothers, and one older sibling. Thus, the incidence of PCD in neonates was 1:29,351. All affected neonates and mothers were asymptomatic except one mother with dilated cardiomyopathy. SLC22A5 gene sequencing identified biallelic causative variants in all cases, comprising 10 different variants of which four were novel. c.51C > G (p.Phe17Leu) and c.760C > T (p.Arg254Ter) were the most prevalent variants in this study. Cases with significant clinical features tended to have higher C0 clearance values. CONCLUSIONS Primary carnitine deficiency is a common inherited metabolic disorder (IMD) in Thailand. Our findings broaden the spectrum of SLC22A5 variants. The future national NBS program will shed more light on PCD and other IMDs in Thailand.
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Affiliation(s)
- Somporn Liammongkolkul
- Division of Medical Genetics, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Boonchai Boonyawat
- Division of Medical Genetics, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Chodchanok Vijarnsorn
- Division of Cardiology, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Thipwimol Tim-Aroon
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Ramathbodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pornswan Wasant
- Division of Medical Genetics, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nithiwat Vatanavicharn
- Division of Medical Genetics, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
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14
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Khries M, Lim A, Mitra D, Anderson M, Bengtsson J, Bowron A, Harris E, Blickwedel J, Wood K, Basu AP. Broadening the Spectrum of SLC22A5 Phenotype: Primary Carnitine Deficiency Presenting with Focal Myoclonus. Child Neurol Open 2023; 10:2329048X231184183. [PMID: 37475835 PMCID: PMC10354736 DOI: 10.1177/2329048x231184183] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 06/07/2023] [Indexed: 07/22/2023] Open
Abstract
Primary carnitine deficiency (PCD) is caused by pathogenic variants of the SLC22A5 gene, which encodes a transmembrane protein that functions as a high affinity carnitine transporter. Carnitine is essential for the transport of acyl-CoA, produced from fatty acids, into the mitochondria where they are oxidised to produce energy. We present the case history of an 8-year-old boy who presented with fever, lethargy, focal rhythmic (3 Hz) left wrist twitching, and severe encephalopathy. MRI brain showed basal ganglia involvement. Metabolic investigations revealed low serum carnitine; whole genome sequencing confirmed compound heterozygous SLC22A5 mutations. With carnitine replacement, intensive care support, and neurorehabilitation, he made a remarkable recovery, regaining independent breathing, speech, mobility, and hand use. Seizure presentation in PCD is rare and presentation with sustained focal myoclonus has not been previously reported. This case expands the known phenotype of PCD. Prompt carnitine replacement is imperative.
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Affiliation(s)
- Maymunah Khries
- Paediatric Neurology, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Albert Lim
- Paediatric Neurology, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Dipayan Mitra
- Neuroradiology, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Mark Anderson
- Paediatrics, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Jan Bengtsson
- Paediatric Intensive Care Unit, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Ann Bowron
- Metabolic Biochemistry, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Elizabeth Harris
- Northern Genetics Service, Centre for Life, Newcastle upon Tyne, UK
| | - Jessica Blickwedel
- Paediatric Neurology, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Karen Wood
- Paediatric Neurology, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Anna P. Basu
- Paediatric Neurology, Great North Children's Hospital, Newcastle upon Tyne, UK
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK
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15
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Crefcoeur LL, Heiner‐Fokkema MR, Maase RE, Visser G, de Sain‐van der Velden MGM. Assessment of carnitine excretion and its ratio to plasma free carnitine as a biomarker for primary carnitine deficiency in newborns. JIMD Rep 2023; 64:57-64. [PMID: 36636597 PMCID: PMC9830017 DOI: 10.1002/jmd2.12334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 08/31/2022] [Indexed: 01/16/2023] Open
Abstract
In the Netherlands, newborns are referred by the newborn screening (NBS) Program when a low free carnitine (C0) concentration (<5 μmol/l) is detected in their NBS dried blood spot. This leads to ~85% false positive referrals who all need an invasive, expensive and lengthy evaluation. We investigated whether a ratio of urine C0 / plasma C0 (RatioU:P) can improve the follow-up protocol for primary carnitine deficiency (PCD). A retrospective study was performed in all Dutch metabolic centres, using samples from newborns and mothers referred by NBS due to low C0 concentration. Samples were included when C0 excretion and plasma C0 concentration were sampled on the same day. RatioU:P was calculated as (urine C0 [μmol/mmol creatinine])/(plasma C0 [μmol/l]). Data were available for 59 patients with genetically confirmed PCD and 68 individuals without PCD. The RatioU:P in PCD patients was significantly higher (p value < 0.001) than in those without PCD, median [IQR], respectively: 3.4 [1.2-9.5], 0.4 [0.3-0.8], area under the curve (AUC) 0.837. Classified for age (up to 1 month) and without carnitine suppletion (PCD; N = 12, Non-PCD; N = 40), medians were 6.20 [4.4-8.8] and 0.37 [0.24-0.56], respectively. The AUC for RatioU:P was 0.996 with a cut-off required for 100% sensitivity at 1.7 (yielding one false positive case). RatioU:P accurately discriminates between positive and false positive newborn referrals for PCD by NBS. RatioU:P is less effective as a discriminative tool for PCD in adults and for individuals that receive carnitine suppletion.
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Affiliation(s)
- Loek L. Crefcoeur
- Department of Metabolic Diseases, Wilhelmina Children's HospitalUniversity Medical Center UtrechtUtrechtThe Netherlands
- Division of Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Emma Children's HospitalAmsterdam UMC, Location University of AmsterdamAmsterdamThe Netherlands
| | - M. Rebecca Heiner‐Fokkema
- Department of Laboratory MedicineUniversity of Groningen, University Medical Center GroningenGroningenThe Netherlands
| | - Rose E. Maase
- Department Biologicals, Screening and InnovationDutch National Institute for Public Health and the EnvironmentBilthovenThe Netherlands
| | - Gepke Visser
- Department of Metabolic Diseases, Wilhelmina Children's HospitalUniversity Medical Center UtrechtUtrechtThe Netherlands
- Division of Metabolic Diseases, Amsterdam Gastroenterology and Metabolism, Emma Children's HospitalAmsterdam UMC, Location University of AmsterdamAmsterdamThe Netherlands
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16
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Gao W, Wu L, Jin S, Li J, Liu X, Xu J, Zhang W, Gong Q, Sun C, Wang W, Wang Z, Shao YW, Yin JC, Shen L, Chen L, Wang Q, Guo R. Rechallenge of immune checkpoint inhibitors in a case with adverse events inducing myasthenia gravis. J Immunother Cancer 2022; 10:jitc-2022-005970. [PMID: 36450378 PMCID: PMC9716945 DOI: 10.1136/jitc-2022-005970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2022] [Indexed: 12/02/2022] Open
Abstract
The mechanism(s) of immune checkpoint inhibitor (ICI)-induced myasthenia gravis (MG), an immune-related adverse event (irAE) that is fatal and limits subsequent ICI use, remain unexplored. Here, through comparative genomic analysis, we identified a pathogenic p.S467C germline variant in SLC22A5 in a thymoma case with ICI-induced MG, which was found to be associated with fatty acid oxidation through its regulation on L-carnitine levels. Remarkably, ICI rechallenge with L-carnitine pretreatment led to durable response without MG-related symptoms. Thus, we provide the first clinical evidence of genetic test-directed irAE management, which integrates individualized ICI treatment into the evolving paradigm of cancer management.
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Affiliation(s)
- Wen Gao
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Lingxiang Wu
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Medicine, Nanjing Medical University, Nanjing, Jiangsu, China,Department of Bioinformatics, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shidai Jin
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jun Li
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xinyin Liu
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiali Xu
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wei Zhang
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qixing Gong
- Department of Pathology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Chunxiao Sun
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wei Wang
- Department of Neurology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zidun Wang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yang W Shao
- Geneseeq Research Institute, Nanjing Geneseeq Technology Inc, Nanjing, Jiangsu, China,School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiani C Yin
- Geneseeq Research Institute, Nanjing Geneseeq Technology Inc, Nanjing, Jiangsu, China
| | - Lu Shen
- Geneseeq Research Institute, Nanjing Geneseeq Technology Inc, Nanjing, Jiangsu, China
| | - Liang Chen
- Department of Thoracic Surgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qianghu Wang
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Medicine, Nanjing Medical University, Nanjing, Jiangsu, China,Department of Bioinformatics, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Renhua Guo
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
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17
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Koleske ML, McInnes G, Brown JEH, Thomas N, Hutchinson K, Chin MY, Koehl A, Arkin MR, Schlessinger A, Gallagher RC, Song YS, Altman RB, Giacomini KM. Functional genomics of OCTN2 variants informs protein-specific variant effect predictor for Carnitine Transporter Deficiency. Proc Natl Acad Sci U S A 2022; 119:e2210247119. [PMID: 36343260 PMCID: PMC9674959 DOI: 10.1073/pnas.2210247119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/16/2022] [Indexed: 11/09/2022] Open
Abstract
Genetic variants in SLC22A5, encoding the membrane carnitine transporter OCTN2, cause the rare metabolic disorder Carnitine Transporter Deficiency (CTD). CTD is potentially lethal but actionable if detected early, with confirmatory diagnosis involving sequencing of SLC22A5. Interpretation of missense variants of uncertain significance (VUSs) is a major challenge. In this study, we sought to characterize the largest set to date (n = 150) of OCTN2 variants identified in diverse ancestral populations, with the goals of furthering our understanding of the mechanisms leading to OCTN2 loss-of-function (LOF) and creating a protein-specific variant effect prediction model for OCTN2 function. Uptake assays with 14C-carnitine revealed that 105 variants (70%) significantly reduced transport of carnitine compared to wild-type OCTN2, and 37 variants (25%) severely reduced function to less than 20%. All ancestral populations harbored LOF variants; 62% of green fluorescent protein (GFP)-tagged variants impaired OCTN2 localization to the plasma membrane of human embryonic kidney (HEK293T) cells, and subcellular localization significantly associated with function, revealing a major LOF mechanism of interest for CTD. With these data, we trained a model to classify variants as functional (>20% function) or LOF (<20% function). Our model outperformed existing state-of-the-art methods as evaluated by multiple performance metrics, with mean area under the receiver operating characteristic curve (AUROC) of 0.895 ± 0.025. In summary, in this study we generated a rich dataset of OCTN2 variant function and localization, revealed important disease-causing mechanisms, and improved upon machine learning-based prediction of OCTN2 variant function to aid in variant interpretation in the diagnosis and treatment of CTD.
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Affiliation(s)
- Megan L. Koleske
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143
| | - Gregory McInnes
- Biomedical Informatics Training Program, Stanford University, Stanford, CA 94305
- Empirico Inc., San Diego, CA 92122
| | - Julia E. H. Brown
- Program in Bioethics, University of California, San Francisco, CA 94143
- Institute for Health & Aging, University of California, San Francisco, CA 94143
| | - Neil Thomas
- Computer Science Division, University of California, Berkeley, CA 94720
| | - Keino Hutchinson
- Department of Pharmacological Sciences, Icahn School of Medicine at Mt. Sinai, New York, NY 10029
| | - Marcus Y. Chin
- Small Molecule Discovery Center, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143
| | - Antoine Koehl
- Department of Statistics, University of California, Berkeley, CA 94720
| | - Michelle R. Arkin
- Small Molecule Discovery Center, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mt. Sinai, New York, NY 10029
| | - Renata C. Gallagher
- Institute for Human Genetics, University of California, San Francisco, CA 94143
- Department of Pediatrics, University of California, San Francisco, CA 94143
| | - Yun S. Song
- Computer Science Division, University of California, Berkeley, CA 94720
- Department of Statistics, University of California, Berkeley, CA 94720
| | - Russ B. Altman
- Department of Bioengineering, Stanford University, Stanford, CA 94305
- Department of Genetics, Stanford University, Stanford, CA 94305
| | - Kathleen M. Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143
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18
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Crefcoeur LL, Melles MC, Bruning TA, Pereira RR, Langendonk JG. Primary carnitine deficiency is a life-long disease. JIMD Rep 2022; 63:524-528. [PMID: 36341172 PMCID: PMC9626665 DOI: 10.1002/jmd2.12319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/08/2022] [Accepted: 07/12/2022] [Indexed: 11/24/2022] Open
Abstract
Primary carnitine deficiency is a rare autosomal recessive disease associated with acute hypoketotic hypoglycaemia, cardiomyopathy and sudden cardiac death. Effective treatment with carnitine supplementation is available. An 18 months old boy, who presented with cardiomyopathy was diagnosed with primary carnitine deficiency, and carnitine supplementation resulted in a full recovery. At age 13 years, he discontinued his medication and at 20 years, he discontinued clinical monitoring. Nine years later, age 29, he presented with heart failure and atrial fibrillation and was admitted to an intensive care unit, where he was treated with furosemide, enoximone and intravenous carnitine supplementation, this lead to improved cardiac function within 2 weeks, and with continued oral carnitine supplements, his left ventricular ejection fraction normalised. The last 8 years were uneventful and he continued to attend his regular follow-up visits at a specialised metabolic outpatient clinic. We report recurrent reversible severe heart failure in a patient with primary carnitine deficiency; it was directly related to non-compliance to carnitine supplementation (and monitoring). This case report emphasises first, the importance of continued monitoring of metabolic disease patients, second, the potential reversibility of cardiomyopathy in an adult patient, and third, the potential risks in the period of transition from the paediatric to adult care. This is an age where young adults desire to be healthy and ignore the need for ongoing medical treatment, even as simple as oral suppletion. Before they reach this age, adequate disease insight and self-management of the disease should be promoted.
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Affiliation(s)
- Loek L. Crefcoeur
- Department of Metabolic DiseasesWilhelmina Children's Hospital, University Medical Center UtrechtUtrechtNetherlands
- Laboratory Genetic Metabolic DiseasesAmsterdam UMC location Academic Medical Center, University of Amsterdam, Amsterdam Gastroenterology and MetabolismAmsterdamNetherlands
| | | | | | | | - Janneke G. Langendonk
- Department of Internal Medicine, Center for Lysosomal and Metabolic DiseasesErasmus MC, University Medical Centre RotterdamRotterdamNetherlands
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19
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Yin K, Zhang K, Zhao Q, Wu Q, Zheng J, Zhou N, Tang S, Makielski JC, Cheng J. Electrocardiographic and Echocardiographic Features of Carnitine-Deficient Animal Model. J Biomed Nanotechnol 2022. [DOI: 10.1166/jbn.2022.3429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Primary systemic carnitine deficiency (CDSP) is a rare disease that can lead to sudden cardiac death (SCD). Meanwhile, cardiac manifestations had been widely reported in CDSP cases. Researches on phenotype and mechanism are needed imperatively to evaluate the influence of carnitine
deficiency on cardiovascular system. We induce an intraperitonealinjected carnitine deficiency mouse model and a transgenic mouse model created by CRISPR/Cas-mediated genome engineering to observe the ECG and echocardiography parameters to explore the cardiac pathophysiological features in
carnitine deficiency. In female drug-induced carnitine-deficient mice, the tendency of shortened QTc interval existed in experimental groups compared with the control group (P<0 05). Statistically significant differences in QTc interval existed in low-dose as well as high-dose groups
and control (P<0 05). The same rule appeared in heart rate (HR) and T wave duration (P<0 05). After 8 weeks of continuous injection, HR, left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS) in low-dose group, HR as well as LVPWd in high-dose
group increased significantly compared with the control (all P<0 05). In male drug-induced carnitine deficient mice, the tendency of shortened QTc interval also existed in experimental groups compared with the control group (P<0 05). Statistically significant differences in QTc
interval existed in low-dose group and control (P<0 05). Compared with the control, PR interval declined significantly in high-dose group (P<0 05). After 8 weeks of continuous injection, no cardiac functional indexes in experimental groups altered significantly compared
with the control (all P>0 05) were found. In transgenic mice, free carnitine (C0) level statistically decreased (P<0 05) compared with the wild-type (WT) mice. There was no statistical difference between mice carried two single heterozygote (P>0 05). However, C0 level
between compound heterozygote and single heterozygote was statistically significant (P>0 05). Moreover, there were no significant differences recorded compared with WT in ECG and echocardiography (P>0 05). This study suggested that carnitine deficiency had impact on cardiac
function and structure in some situations. We summarized the ECG and echocardiography features of carnitine-deficient mice model and build the first transgenic animal model imitating the pathogenic genotype in human CDSP patients, which provide a foundation for further research on pathophysiological
and molecular mechanism.
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Affiliation(s)
- Kun Yin
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Kai Zhang
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Qianhao Zhao
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Qiuping Wu
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Jingjing Zheng
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Nan Zhou
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Shuangbo Tang
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Jonathan C. Makielski
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, 53792, WI, USA
| | - Jianding Cheng
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
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20
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Crefcoeur LL, Visser G, Ferdinandusse S, Wijburg FA, Langeveld M, Sjouke B. Clinical characteristics of primary carnitine deficiency: A structured review using a case-by-case approach. J Inherit Metab Dis 2022; 45:386-405. [PMID: 34997761 PMCID: PMC9305179 DOI: 10.1002/jimd.12475] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 11/24/2022]
Abstract
A broad spectrum of signs and symptoms has been attributed to primary carnitine deficiency (PCD) since its first description in 1973. Advances in diagnostic procedures have improved diagnostic accuracy and the introduction of PCD in newborn screening (NBS) programs has led to the identification of an increasing number of PCD patients, including mothers of screened newborns, who may show a different phenotype compared to clinically diagnosed patients. To elucidate the spectrum of signs and symptoms in PCD patients, we performed a structured literature review. Using a case-by-case approach, clinical characteristics, diagnostic data, and mode of patient identification were recorded. Signs and symptoms were categorized by organ involvement. In total, 166 articles were included, reporting data on 757 individual patients. In almost 20% (N = 136) of the cases, the diagnosis was based solely on low carnitine concentration which we considered an uncertain diagnosis of PCD. The remaining 621 cases had a diagnosis based on genetic and/or functional (ie, carnitine transporter activity) test results. In these 621 cases, cardiac symptoms (predominantly cardiomyopathy) were the most prevalent (23.8%). Neurological (7.1%), hepatic (8.4%), and metabolic (9.2%) symptoms occurred mainly in early childhood. Adult onset of symptoms occurred in 16 of 194 adult patients, of whom 6 (3.1%) patients suffered a severe event without any preceding symptom (five cardiac events and one coma). In conclusion, symptoms in PCD predominantly develop in early childhood. Most newborns and mothers of newborns detected through NBS remain asymptomatic. However, though rarely, severe complications do occur in both groups.
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Affiliation(s)
- Loek L. Crefcoeur
- Department of Metabolic Diseases, Wilhelmina Children's HospitalUniversity Medical Center UtrechtUtrechtThe Netherlands
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC location Academic Medical CenterUniversity of Amsterdam, Amsterdam Gastroenterology and MetabolismAmsterdamThe Netherlands
| | - Gepke Visser
- Department of Metabolic Diseases, Wilhelmina Children's HospitalUniversity Medical Center UtrechtUtrechtThe Netherlands
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC location Academic Medical CenterUniversity of Amsterdam, Amsterdam Gastroenterology and MetabolismAmsterdamThe Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC location Academic Medical CenterUniversity of Amsterdam, Amsterdam Gastroenterology and MetabolismAmsterdamThe Netherlands
| | - Frits A. Wijburg
- Emma's Children's Hospital, Amsterdam UMC location Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Mirjam Langeveld
- Department of Endocrinology and Metabolism, Amsterdam UMC location Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Barbara Sjouke
- Department of Endocrinology and Metabolism, Amsterdam UMC location Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
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21
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Stenlid R, Olsson D, Cen J, Manell H, Haglind C, Chowdhury AI, Bergsten P, Nordenström A, Halldin M. Altered mitochondrial metabolism in peripheral blood cells from patients with inborn errors of β-oxidation. Clin Transl Sci 2021; 15:182-194. [PMID: 34437764 PMCID: PMC8742636 DOI: 10.1111/cts.13133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/18/2021] [Accepted: 07/22/2021] [Indexed: 12/15/2022] Open
Abstract
Inborn errors of mitochondrial fatty acid oxidation (FAO), such as medium-chain acyl-CoA dehydrogenase deficiency (MCAD) and very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) affects cellular function and whole-body metabolism. Carnitine uptake deficiency (CUD) disturbs the transportation of fatty acids into the mitochondria, but when treated is a mild disease without significant effects on FAO. For improved clinical care of VLCAD in particular, estimation of FAO severity could be important. We have investigated whether the oxygen consumption rate (OCR) of peripheral blood mononuclear cells (PBMCs) obtained from patients with MCAD, VLCAD, and CUD can be used to study cellular metabolism in patients with FAO defects and to determine the severity of FAO impairment. PBMCs were isolated from patients with VLCAD (n = 9), MCAD (n = 5-7), and CUD (n = 5). OCR was measured within 6-hours of venous puncture using the Seahorse XFe96. The PBMCs were exposed to glucose alone or with caprylic acid (C8:0) or palmitic acid (C16:0). OCR was significantly lower in cells from patients with β-oxidation deficiencies (MCAD and VLCAD) compared to CUD at basal conditions. When exposed to C16:0, OCR in VLCAD cells was unchanged, whereas OCR in MCAD cells increased but not to the levels observed in CUD. However, C8:0 did not increase OCR, as would be expected, in VLCAD cells. There was no clear relationship between clinical severity level and OCR. In patients with β-oxidation deficiencies, changes of mitochondrial respiration in PBMCs are detectable, which indicate that PBMCs have translational potential for studies of β-oxidation defects. However, further studies are warranted.
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Affiliation(s)
- Rasmus Stenlid
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - David Olsson
- Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden.,Department of Paediatric Endocrinology and Metabolic Disorders, Astrid Lindgren Children Hospital, Karolinska University Hospital, Solna, Sweden
| | - Jing Cen
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Hannes Manell
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Charlotte Haglind
- Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden
| | | | - Peter Bergsten
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Anna Nordenström
- Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden.,Department of Paediatric Endocrinology and Metabolic Disorders, Astrid Lindgren Children Hospital, Karolinska University Hospital, Solna, Sweden
| | - Maria Halldin
- Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden.,Department of Paediatric Endocrinology and Metabolic Disorders, Astrid Lindgren Children Hospital, Karolinska University Hospital, Solna, Sweden
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22
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Yang X, Li Q, Wang F, Yan L, Zhuang D, Qiu H, Li H, Chen L. Newborn Screening and Genetic Analysis Identify Six Novel Genetic Variants for Primary Carnitine Deficiency in Ningbo Area, China. Front Genet 2021; 12:686137. [PMID: 34249102 PMCID: PMC8264545 DOI: 10.3389/fgene.2021.686137] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/03/2021] [Indexed: 12/30/2022] Open
Abstract
Primary carnitine deficiency (PCD) is an autosomal recessive disorder that could result in sudden death. It is caused by a defect in the carnitine transporter encoded by SLC22A5 (Solute Carrier Family 22 Member 5, MIM:603377). Currently, a number of variants in SLC22A5 have been identified, however, the PCD prevalence and its variants in Ningbo area are unclear. In this study, we screened 265,524 newborns by using tandem mass spectrometry. Variants in SLC22A5 were further detected by next-generation sequencing in individuals with abnormal free carnitine levels (C0). We identified 53 newborns with abnormal C0 levels and 26 with variants in SLC22A5. Among them, 16 with compound heterozygous or homozygous variants in SLC22A5 were diagnosed with PCD, suggesting the PCD birth prevalence in Ningbo city was 1/16,595. Moreover, the C0 level was significantly (P = 0.013) higher in PCD patients than in those with one variant. Besides, the c.1400C > G (p. S467C) and c.51C > G (p. F17L) variants were the most frequent and six novel variants are all predicted to be damaging. This study reports the largest PCD patients in Ningbo area by newborn screening and expands the variant spectrum of SLC22A5. Our findings demonstrate the clinical value of combining NBS program results with DNA analysis for the diagnosis of PCD.
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Affiliation(s)
- Xiangchun Yang
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, China
| | - Qiong Li
- Neonatal Screening Center, Ningbo Women and Children's Hospital, Ningbo, China
| | - Fei Wang
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, China
| | - Lulu Yan
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, China
| | - Danyan Zhuang
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, China
| | - Haiyan Qiu
- Department of Pediatrics, Ningbo Women and Children's Hospital, Ningbo, China
| | - Haibo Li
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, China
| | - Liang Chen
- Department of Gynaecology, Ningbo Women and Children's Hospital, Ningbo, China
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23
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Schiergens KA, Weiss KJ, Röschinger W, Lotz-Havla AS, Schmitt J, Dalla Pozza R, Ulrich S, Odenwald B, Kreuder J, Maier EM. Newborn screening for carnitine transporter defect in Bavaria and the long-term follow-up of the identified newborns and mothers: Assessing the benefit and possible harm based on 19 ½ years of experience. Mol Genet Metab Rep 2021; 28:100776. [PMID: 34178604 PMCID: PMC8214137 DOI: 10.1016/j.ymgmr.2021.100776] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 12/30/2022] Open
Abstract
Carnitine transporter defect (CTD) is a potentially life-threatening disorder causing acute metabolic decompensation, cardiac arrhythmia, and cardiac and skeletal myopathies. CTD is included in many newborn screening (NBS) programs. The screening parameter free carnitine, however, is influenced by maternal conditions due to placental transfer. This study reviewed the NBS results for CTD as part of a pilot study in Bavaria, Germany, and the long-term follow-up of the identified patients treated in our center between January 1999 and June 2018. Among 1,816,000 Bavarian NBS samples, six newborns were diagnosed with CTD (incidence of 1:302,667; positive predictive value (PPV) of 1.63% from 2008 to 2018). In the 24 newborns presented to our center for confirmatory testing, we detected four newborns and six mothers with CTD, one newborn and three mothers in whom CTD was presumed but not genetically confirmed, and one mother with glutaric aciduria type I. In 11 newborns, no indication for an inborn error of metabolism was found. The newborns and mothers with CTD had no serious cardiac adverse events or relevant muscular symptoms at diagnosis and during treatment for up to 14 years. Three mothers were lost to follow-up. Revealing a lower incidence than expected, our data confirm that NBS for CTD most likely misses newborns with CTD. It rather produces high numbers of false-positives and a low PPV picking up asymptomatic mothers with a diagnosis of uncertain clinical significance. Our data add to the growing evidence that argues against an implementation of CTD in NBS programs. Newborn screening (NBS) aims at early detection and treatment of relevant disorders. High numbers of false-positives burden the healthy population and health care systems. NBS for carnitine transporter defect produces high numbers of false-positives. NBS for carnitine transporter defect picks up asymptomatic mothers. Selective screening at clinical suspicion more suitable than population screening.
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Affiliation(s)
- Katharina A Schiergens
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Lindwurmstr. 4, 80337, Munich, Germany
| | - Katharina J Weiss
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Lindwurmstr. 4, 80337, Munich, Germany
| | - Wulf Röschinger
- Newborn Screening Unit, Becker and colleagues laboratory, Ottobrunner Str. 6, 81737, Munich, Germany
| | - Amelie S Lotz-Havla
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Lindwurmstr. 4, 80337, Munich, Germany
| | - Joachim Schmitt
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Lindwurmstr. 4, 80337, Munich, Germany
| | - Robert Dalla Pozza
- Department of Pediatric Cardiology, Munich University Hospital, Marchioninistr. 15, 81377 Munich, Germany
| | - Sarah Ulrich
- Department of Pediatric Cardiology, Munich University Hospital, Marchioninistr. 15, 81377 Munich, Germany
| | - Birgit Odenwald
- Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany
| | - Joachim Kreuder
- Pediatric Heart Center, Justus-Liebig-University, Feulgenstr. 10-12, 35392 Giessen, Germany
| | - Esther M Maier
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Lindwurmstr. 4, 80337, Munich, Germany
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24
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Jakoby M, Jaju A, Marsh A, Wilber A. Maternal Primary Carnitine Deficiency and a Novel Solute Carrier Family 22 Member 5 (SLC22A5) Mutation. J Investig Med High Impact Case Rep 2021; 9:23247096211019543. [PMID: 34032155 PMCID: PMC8155745 DOI: 10.1177/23247096211019543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Primary carnitine deficiency (PCD) is a rare autosomal recessive disorder caused
by loss of function mutations in the solute carrier family 22 member 5
(SLC22A5) gene that encodes a high-affinity
sodium-ion–dependent organic cation transporter protein (OCTN2). Reduced
carnitine transport results in diminished fatty acid oxidation in heart and
skeletal muscle and carnitine wasting in urine. We present a case of PCD
diagnosed in an adult female after a positive newborn screen (NBS) for PCD that
was not confirmed on follow-up testing. The mother was referred for evaluation
of persistent fatigue and possible hypothyroidism even though all measurements
of thyroid-stimulating hormone were well within the range of 0.4 to 2.5 mIU/L
expected for reproductive-age women. She was found to have unequivocally low
levels of both total carnitine and carnitine esters, and genetic testing
revealed compound heterozygosity for 2 SLC22A5 mutations. One mutation
(c.34G>A [p.Gly12Ser]) is a known missense mutation with partial OCTN2
activity, but the other mutation (c.41G>A [p.Trp14Ter]) is previously
unreported and results in a premature stop codon and truncated OCTN2. This case
illustrates that some maternal inborn errors of metabolism can be identified by
NBS and that maternal carnitine levels should be checked after a positive NBS
test for PCD.
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Affiliation(s)
| | - Amruta Jaju
- Southern Illinois University, Springfield, IL, USA
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25
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Tonazzi A, Giangregorio N, Console L, Palmieri F, Indiveri C. The Mitochondrial Carnitine Acyl-carnitine Carrier (SLC25A20): Molecular Mechanisms of Transport, Role in Redox Sensing and Interaction with Drugs. Biomolecules 2021; 11:biom11040521. [PMID: 33807231 PMCID: PMC8066319 DOI: 10.3390/biom11040521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 12/22/2022] Open
Abstract
The SLC25A20 transporter, also known as carnitine acyl-carnitine carrier (CAC), catalyzes the transport of short, medium and long carbon chain acyl-carnitines across the mitochondrial inner membrane in exchange for carnitine. The 30-year story of the protein responsible for this function started with its purification from rat liver mitochondria. Even though its 3D structure is not yet available, CAC is one of the most deeply characterized transport proteins of the inner mitochondrial membrane. Other than functional, kinetic and mechanistic data, post-translational modifications regulating the transport activity of CAC have been revealed. CAC interactions with drugs or xenobiotics relevant to human health and toxicology and the response of the carrier function to dietary compounds have been discovered. Exploiting combined approaches of site-directed mutagenesis with chemical targeting and bioinformatics, a large set of data on structure/function relationships have been obtained, giving novel information on the molecular mechanism of the transport catalyzed by this protein.
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Affiliation(s)
- Annamaria Tonazzi
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
| | - Nicola Giangregorio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
| | - Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy;
| | - Ferdinando Palmieri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
- Correspondence: (F.P.); (C.I.); Tel.: +39-080-544-3323 (F.P.); Tel.: +39-0984-492939 (C.I.)
| | - Cesare Indiveri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy;
- Correspondence: (F.P.); (C.I.); Tel.: +39-080-544-3323 (F.P.); Tel.: +39-0984-492939 (C.I.)
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Inherited Neuromuscular Disorders: Which Role for Serum Biomarkers? Brain Sci 2021; 11:brainsci11030398. [PMID: 33801069 PMCID: PMC8004068 DOI: 10.3390/brainsci11030398] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/08/2021] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited neuromuscular disorders (INMD) are a heterogeneous group of rare diseases that involve muscles, motor neurons, peripheral nerves or the neuromuscular junction. Several different lab abnormalities have been linked to INMD: sometimes they are typical of the disorder, but they usually appear to be less specific. Sometimes serum biomarkers can point out abnormalities in presymtomatic or otherwise asymptomatic patients (e.g., carriers). More often a biomarker of INMD is evaluated by multiple clinicians other than expert in NMD before the diagnosis, because of the multisystemic involvement in INMD. The authors performed a literature search on biomarkers in inherited neuromuscular disorders to provide a practical approach to the diagnosis and the correct management of INMD. A considerable number of biomarkers have been reported that support the diagnosis of INMD, but the role of an expert clinician is crucial. Hence, the complete knowledge of such abnormalities can accelerate the diagnostic workup supporting the referral to specialists in neuromuscular disorders.
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Lin W, Wang K, Zheng Z, Chen Y, Fu C, Lin Y, Chen D. Newborn screening for primary carnitine deficiency in Quanzhou, China. Clin Chim Acta 2020; 512:166-171. [PMID: 33181153 DOI: 10.1016/j.cca.2020.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS Primary carnitine deficiency (PCD) is an autosomal recessive disease caused by functional defects in the carnitine transporter OCTN2 due to mutations in SLC22A5. Here, we aimed to understand the incidence, clinical, biochemical, and molecular features of PCD in Quanzhou, China. MATERIALS AND METHODS Newborn screening (NBS) was performed through tandem mass spectrometry (MS/MS) to detect genetic metabolic diseases. Next-generation sequencing was used to detect SLC22A5 mutations in patients with suspected PCD. RESULTS From 364,545 newborns screened, 36 were diagnosed with PCD, in addition to five mothers. The incidence of PCD in children in the Quanzhou area was 1:10126. Eighteen SLC22A5 variants were found, with five novel ones. The most prevalent variant in neonatal and maternal patients was c.760C > T (p.R254*). Twenty-five neonatal patients received L-carnitine supplementation; however, one patient discontinued treatment and sudden death occurred. One sibling presented repeated fatigue, hypoglycemia, and coma, but the symptoms disappeared after treatment. Two mothers with PCD claimed to feel weak and easily fatigued. CONCLUSION The incidence of PCD is relatively high in the Quanzhou area. Five novel variants were found, broadening the mutation spectrum of SLC22A5. NBS is effective in identifying PCD, and sudden death may be prevented with timely treatment.
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Affiliation(s)
- Weihua Lin
- Department of Child Health Care, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Kunyi Wang
- Integrated Technical Service Center, Quanzhou Customs, Quanzhou, Fujian Province 362000, China
| | - Zhenzhu Zheng
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Yanru Chen
- Department of Child Health Care, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Caifeng Fu
- Department of Child Health Care, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Yiming Lin
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China.
| | - Dongmei Chen
- Newborn ICU, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China.
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Organic Cation Transporters in Human Physiology, Pharmacology, and Toxicology. Int J Mol Sci 2020; 21:ijms21217890. [PMID: 33114309 PMCID: PMC7660683 DOI: 10.3390/ijms21217890] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/13/2022] Open
Abstract
Individual cells and epithelia control the chemical exchange with the surrounding environment by the fine-tuned expression, localization, and function of an array of transmembrane proteins that dictate the selective permeability of the lipid bilayer to small molecules, as actual gatekeepers to the interface with the extracellular space. Among the variety of channels, transporters, and pumps that localize to cell membrane, organic cation transporters (OCTs) are considered to be extremely relevant in the transport across the plasma membrane of the majority of the endogenous substances and drugs that are positively charged near or at physiological pH. In humans, the following six organic cation transporters have been characterized in regards to their respective substrates, all belonging to the solute carrier 22 (SLC22) family: the organic cation transporters 1, 2, and 3 (OCT1–3); the organic cation/carnitine transporter novel 1 and 2 (OCTN1 and N2); and the organic cation transporter 6 (OCT6). OCTs are highly expressed on the plasma membrane of polarized epithelia, thus, playing a key role in intestinal absorption and renal reabsorption of nutrients (e.g., choline and carnitine), in the elimination of waste products (e.g., trimethylamine and trimethylamine N-oxide), and in the kinetic profile and therapeutic index of several drugs (e.g., metformin and platinum derivatives). As part of the Special Issue Physiology, Biochemistry, and Pharmacology of Transporters for Organic Cations, this article critically presents the physio-pathological, pharmacological, and toxicological roles of OCTs in the tissues in which they are primarily expressed.
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Roman TS, Crowley SB, Roche MI, Foreman AKM, O'Daniel JM, Seifert BA, Lee K, Brandt A, Gustafson C, DeCristo DM, Strande NT, Ramkissoon L, Milko LV, Owen P, Roy S, Xiong M, Paquin RS, Butterfield RM, Lewis MA, Souris KJ, Bailey DB, Rini C, Booker JK, Powell BC, Weck KE, Powell CM, Berg JS. Genomic Sequencing for Newborn Screening: Results of the NC NEXUS Project. Am J Hum Genet 2020; 107:596-611. [PMID: 32853555 PMCID: PMC7536575 DOI: 10.1016/j.ajhg.2020.08.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/24/2020] [Indexed: 02/08/2023] Open
Abstract
Newborn screening (NBS) was established as a public health program in the 1960s and is crucial for facilitating detection of certain medical conditions in which early intervention can prevent serious, life-threatening health problems. Genomic sequencing can potentially expand the screening for rare hereditary disorders, but many questions surround its possible use for this purpose. We examined the use of exome sequencing (ES) for NBS in the North Carolina Newborn Exome Sequencing for Universal Screening (NC NEXUS) project, comparing the yield from ES used in a screening versus a diagnostic context. We enrolled healthy newborns and children with metabolic diseases or hearing loss (106 participants total). ES confirmed the participant's underlying diagnosis in 15 out of 17 (88%) children with metabolic disorders and in 5 out of 28 (∼18%) children with hearing loss. We discovered actionable findings in four participants that would not have been detected by standard NBS. A subset of parents was eligible to receive additional information for their child about childhood-onset conditions with low or no clinical actionability, clinically actionable adult-onset conditions, and carrier status for autosomal-recessive conditions. We found pathogenic variants associated with hereditary breast and/or ovarian cancer in two children, a likely pathogenic variant in the gene associated with Lowe syndrome in one child, and an average of 1.8 reportable variants per child for carrier results. These results highlight the benefits and limitations of using genomic sequencing for NBS and the challenges of using such technology in future precision medicine approaches.
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Affiliation(s)
- Tamara S Roman
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Stephanie B Crowley
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Myra I Roche
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pediatrics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Ann Katherine M Foreman
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Julianne M O'Daniel
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bryce A Seifert
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kristy Lee
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alicia Brandt
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Chelsea Gustafson
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniela M DeCristo
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Natasha T Strande
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lori Ramkissoon
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura V Milko
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Phillips Owen
- Renaissance Computing Institute, Chapel Hill, NC 27517, USA
| | - Sayanty Roy
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mai Xiong
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ryan S Paquin
- Center for Communication Science, RTI International, Research Triangle Park, NC 27709, USA
| | - Rita M Butterfield
- Department of Family Medicine and Community Health, Duke University School of Medicine, Durham, NC 27705, USA
| | - Megan A Lewis
- Center for Communication Science, RTI International, Research Triangle Park, NC 27709, USA
| | - Katherine J Souris
- Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Donald B Bailey
- Genomics, Bioinformatics and Translational Research Center, RTI International, Research Triangle Park, NC 27709, USA
| | - Christine Rini
- Feinberg School of Medicine, Department of Medical Social Sciences, and the Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Jessica K Booker
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bradford C Powell
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Karen E Weck
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Cynthia M Powell
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pediatrics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Jonathan S Berg
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Console L, Scalise M, Mazza T, Pochini L, Galluccio M, Giangregorio N, Tonazzi A, Indiveri C. Carnitine Traffic in Cells. Link With Cancer. Front Cell Dev Biol 2020; 8:583850. [PMID: 33072764 PMCID: PMC7530336 DOI: 10.3389/fcell.2020.583850] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/31/2020] [Indexed: 12/16/2022] Open
Abstract
Metabolic flexibility is a peculiar hallmark of cancer cells. A growing number of observations reveal that tumors can utilize a wide range of substrates to sustain cell survival and proliferation. The diversity of carbon sources is indicative of metabolic heterogeneity not only across different types of cancer but also within those sharing a common origin. Apart from the well-assessed alteration in glucose and amino acid metabolisms, there are pieces of evidence that cancer cells display alterations of lipid metabolism as well; indeed, some tumors use fatty acid oxidation (FAO) as the main source of energy and express high levels of FAO enzymes. In this metabolic pathway, the cofactor carnitine is crucial since it serves as a “shuttle-molecule” to allow fatty acid acyl moieties entering the mitochondrial matrix where these molecules are oxidized via the β-oxidation pathway. This role, together with others played by carnitine in cell metabolism, underlies the fine regulation of carnitine traffic among different tissues and, within a cell, among different subcellular compartments. Specific membrane transporters mediate carnitine and carnitine derivatives flux across the cell membranes. Among the SLCs, the plasma membrane transporters OCTN2 (Organic cation transport novel 2 or SLC22A5), CT2 (Carnitine transporter 2 or SLC22A16), MCT9 (Monocarboxylate transporter 9 or SLC16A9) and ATB0, + [Sodium- and chloride-dependent neutral and basic amino acid transporter B(0+) or SLC6A14] together with the mitochondrial membrane transporter CAC (Mitochondrial carnitine/acylcarnitine carrier or SLC25A20) are the most acknowledged to mediate the flux of carnitine. The concerted action of these proteins creates a carnitine network that becomes relevant in the context of cancer metabolic rewiring. Therefore, molecular mechanisms underlying modulation of function and expression of carnitine transporters are dealt with furnishing some perspective for cancer treatment.
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Affiliation(s)
- Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Tiziano Mazza
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Lorena Pochini
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Michele Galluccio
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy
| | - Nicola Giangregorio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Bari, Italy
| | - Annamaria Tonazzi
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Bari, Italy
| | - Cesare Indiveri
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Arcavacata di Rende, Italy.,Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Bari, Italy
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31
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Diagnosis, genetic characterization and clinical follow up of mitochondrial fatty acid oxidation disorders in the new era of expanded newborn screening: A single centre experience. Mol Genet Metab Rep 2020; 24:100632. [PMID: 32793418 PMCID: PMC7414009 DOI: 10.1016/j.ymgmr.2020.100632] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 02/07/2023] Open
Abstract
Introduction Mitochondrial fatty acid oxidation disorders (FAODs) are a heterogeneous group of hereditary autosomal recessive diseases included in newborn screening (NBS) program in Italy. The aim of this study was to analyse FAODs cases, identified either clinically or by NBS,for clinical and genetic characterization and to evaluate a five years' experience of NBS, in the attempt to figure out the complexity of genotype-phenotype correlation and to confirm the clinical impact of NBS in our centre experience. Materials and methods We analysed FAODs patients diagnosed either by NBS or clinically, followed since February 2014 to April 2019 at the Regional Screening Centre and Inherited Metabolic Diseases Unit of Verona. Diagnosis was confirmed by plasma acylcarnitines, urinary organic acids, enzymatic and genetic testing. For not clear genotypes due to the presence of variants of uncertain significance, in silico predictive tools have been used as well as enzymatic activity assays. Patients underwent clinical, nutritional and biochemical follow up. Results We diagnosed 30 patients with FAODs. 20 by NBS: 3 CUD, 6 SCADD, 5 MCADD, 4 VLCADD, 2 MADD. Overall incidence of FAODs diagnosed by NBS was 1:4316 newborns. No one reported complications during the follow up period. 10 patients were diagnosed clinically: 2 CUD, 2 CPT2D, 1 VLCADD, 5 MADD. Mean age at diagnosis was 29.3 years. Within this group, complications or symptoms were reported at diagnosis, but not during follow-up. 12 mutations not previously reported in literature were found, all predicted as pathogenic or likely pathogenic. Discussion and conclusions Our study highlighted the great phenotypic variability and molecular heterogeneity of FAODs and confirmed the importance of a tailored follow up and treatment. Despite the short duration of follow up, early identification by NBS prevented diseases related complications and resulted in normal growth and psycho-motor development as well. Early identification by newborn screening prevents disease related complications. Newborn screening is changing prevalence clinical and molecular heterogeneity of FAODs. Genotype-phenotype correlation helps to achieve personalized follow-up and treatment. Enzymatic assay may be pivotal in predicting phenotype and symptoms severity. Diagnosis on clinical grounds is anyway important to change disease course.
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Key Words
- ALT, Alanine aminotransferase
- AST, Aspartate aminotransferase
- CACTD, carnitine-acylcarnitine translocase deficiency
- CK, creatine kinase
- CPT1/2 D, carnitine palmitoyl-CoA transferase 1/2 deficiency
- CUD, carnitine uptake defect
- DBS, dried blood spots
- DNA, Deoxyribonucleic acid
- Enzymatic activity
- Expanded newborn screening
- FAODs, fatty acid oxidation disorders
- Fatty acid oxidation defects
- Hypoglycaemia
- LCHADD, Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency
- MADD, multiple acyl-CoA dehydrogenase deficiency
- MCADD, medium-chain acyl-CoA dehydrogenase deficiency
- Myopathy
- NBS, newborn screening
- NGS, next generation sequencing
- PCR, polymerase chain reaction
- SCADD, short chain acyl-CoA dehydrogenase deficiency
- Synergistic heterozygosity
- TFPD, trifunctional protein deficiency
- TMS, tandem mass spectrometry
- VLCADD, very-long-chain acyl-CoA dehydrogenase deficiency
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32
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Wang T, Ma J, Zhang Q, Gao A, Wang Q, Li H, Xiang J, Wang B. Expanded Newborn Screening for Inborn Errors of Metabolism by Tandem Mass Spectrometry in Suzhou, China: Disease Spectrum, Prevalence, Genetic Characteristics in a Chinese Population. Front Genet 2019; 10:1052. [PMID: 31737040 PMCID: PMC6828960 DOI: 10.3389/fgene.2019.01052] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 10/01/2019] [Indexed: 12/30/2022] Open
Abstract
Expanded newborn screening for inborn errors of metabolism (IEMs) by tandem mass spectrometry (MS/MS) could simultaneously analyze more than 40 metabolites and identify about 50 kinds of IEMs. Next generation sequencing (NGS) targeting hundreds of IMEs-associated genes as a follow-up test in expanded newborn screening has been used for genetic analysis of patients. The spectrum, prevalence, and genetic characteristic of IEMs vary dramatically in different populations. To determine the spectrum, prevalence, and gene mutations of IEMs in newborns in Suzhou, China, 401,660 newborns were screened by MS/MS and 138 patients were referred to genetic analysis by NGS. The spectrum of 22 IEMs were observed in Suzhou population of newborns, and the overall incidence (excluding short chain acyl-CoA dehydrogenase deficiency (SCADD) and 3-Methylcrotonyl-CoA carboxylase deficiency (3-MCCD)) was 1/3,163. The prevalence of each IEM ranged from 1/401,660 to 1/19,128, while phenylketonuria (PKU) (1/19,128) and Mild hyperphenylalaninemia (M-HPA) (1/19,128) were the most common IEMs, followed by primary carnitine uptake defect (PCUD) (1/26,777), SCADD (1/28,690), hypermethioninemia (H-MET) (1/30,893), 3-MCCD (1/33,412) and methylmalonic acidemia (MMA) (1/40,166). Moreover, 89 reported mutations and 51 novel mutations in 25 IMEs-associated genes were detected in 138 patients with one of 22 IEMs. Some hotspot mutations were observed for ten IEMs, including PAH gene c.728G > A, c.611A > G, and c.721C > T for Phenylketonuria, PAH gene c.158G > A, c.1238G > C, c.728G > A, and c.1315+6T > A for M-HPA, SLC22A5 gene c.1400C > G, c.51C > G, and c.760C > T for PCUD, ACADS gene c.1031A > G, c.164C > T, and c.1130C > T for SCAD deficiency, MAT1A gene c.791G > A for H-MET, MCCC1 gene c.639+2T > A and c.863A > G for 3-MCCD, MMUT gene c.1663G > A for MMA, SLC25A13 gene c.IVS16ins3Kb and c.852_855delTATG for cittrullinemia II, PTS gene c.259C > T and c.166G > A for Tetrahydrobiopterin deficiency, and ACAD8 gene c.1000C > T and c.286C > A for Isobutyryl coa dehydrogenase deficiency. All these hotspot mutations were reported to be pathogenic or likely pathogenic, except a novel mutation of ACAD8 gene c.286C > A. These mutational hotspots could be potential candidates for gene screening and these novel mutations expanded the mutational spectrum of IEMs. Therefore, our findings could be of value for genetic counseling and genetic diagnosis of IEMs.
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Affiliation(s)
- Ting Wang
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Jun Ma
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Qin Zhang
- Genetic Clinic, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Ang Gao
- Genetic Clinic, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Qi Wang
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Hong Li
- Infertility Clinic, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Jingjing Xiang
- Genetic Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Benjing Wang
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
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33
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Almannai M, Alfadhel M, El-Hattab AW. Carnitine Inborn Errors of Metabolism. Molecules 2019; 24:molecules24183251. [PMID: 31500110 PMCID: PMC6766900 DOI: 10.3390/molecules24183251] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 08/29/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022] Open
Abstract
Carnitine plays essential roles in intermediary metabolism. In non-vegetarians, most of carnitine sources (~75%) are obtained from diet whereas endogenous synthesis accounts for around 25%. Renal carnitine reabsorption along with dietary intake and endogenous production maintain carnitine homeostasis. The precursors for carnitine biosynthesis are lysine and methionine. The biosynthetic pathway involves four enzymes: 6-N-trimethyllysine dioxygenase (TMLD), 3-hydroxy-6-N-trimethyllysine aldolase (HTMLA), 4-N-trimethylaminobutyraldehyde dehydrogenase (TMABADH), and γ-butyrobetaine dioxygenase (BBD). OCTN2 (organic cation/carnitine transporter novel type 2) transports carnitine into the cells. One of the major functions of carnitine is shuttling long-chain fatty acids across the mitochondrial membrane from the cytosol into the mitochondrial matrix for β-oxidation. This transport is achieved by mitochondrial carnitine–acylcarnitine cycle, which consists of three enzymes: carnitine palmitoyltransferase I (CPT I), carnitine-acylcarnitine translocase (CACT), and carnitine palmitoyltransferase II (CPT II). Carnitine inborn errors of metabolism could result from defects in carnitine biosynthesis, carnitine transport, or mitochondrial carnitine–acylcarnitine cycle. The presentation of these disorders is variable but common findings include hypoketotic hypoglycemia, cardio(myopathy), and liver disease. In this review, the metabolism and homeostasis of carnitine are discussed. Then we present details of different inborn errors of carnitine metabolism, including clinical presentation, diagnosis, and treatment options. At the end, we discuss some of the causes of secondary carnitine deficiency.
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Affiliation(s)
- Mohammed Almannai
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh 11525, Saudi Arabia.
| | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh 11426, Saudi Arabia.
- King Abdullah International Medical Research Center (KAIMRC), Riyadh 11426, Saudi Arabia.
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia.
| | - Ayman W El-Hattab
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, UAE.
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Ferdinandusse S, Te Brinke H, Ruiter JPN, Haasjes J, Oostheim W, van Lenthe H, IJlst L, Ebberink MS, Wanders RJA, Vaz FM, Waterham HR. A mutation creating an upstream translation initiation codon in SLC22A5 5'UTR is a frequent cause of primary carnitine deficiency. Hum Mutat 2019; 40:1899-1904. [PMID: 31187905 PMCID: PMC6790604 DOI: 10.1002/humu.23839] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/28/2019] [Accepted: 06/05/2019] [Indexed: 12/31/2022]
Abstract
Primary carnitine deficiency is caused by a defect in the active cellular uptake of carnitine by Na+ -dependent organic cation transporter novel 2 (OCTN2). Genetic diagnostic yield for this metabolic disorder has been relatively low, suggesting that disease-causing variants are missed. We Sanger sequenced the 5' untranslated region (UTR) of SLC22A5 in individuals with possible primary carnitine deficiency in whom no or only one mutant allele had been found. We identified a novel 5'-UTR c.-149G>A variant which we characterized by expression studies with reporter constructs in HeLa cells and by carnitine-transport measurements in fibroblasts using a newly developed sensitive assay based on tandem mass spectrometry. This variant, which we identified in 57 of 236 individuals of our cohort, introduces a functional upstream out-of-frame translation initiation codon. We show that the codon suppresses translation from the wild-type ATG of SLC22A5, resulting in reduced OCTN2 protein levels and concomitantly lower transport activity. With an allele frequency of 24.2% the c.-149G>A variant is the most frequent cause of primary carnitine deficiency in our cohort and may explain other reported cases with an incomplete genetic diagnosis. Individuals carrying this variant should be clinically re-evaluated and monitored to determine if this variant has clinical consequences.
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Affiliation(s)
- Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Heleen Te Brinke
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Jos P N Ruiter
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Janet Haasjes
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Wendy Oostheim
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Henk van Lenthe
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Lodewijk IJlst
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Merel S Ebberink
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Frédéric M Vaz
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology and Metabolism Research Institute, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
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Guevara-Campos J, González-Guevara L, Guevara-González J, Cauli O. First Case Report of Primary Carnitine Deficiency Manifested as Intellectual Disability and Autism Spectrum Disorder. Brain Sci 2019; 9:brainsci9060137. [PMID: 31200524 PMCID: PMC6628273 DOI: 10.3390/brainsci9060137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 12/26/2022] Open
Abstract
Systemic primary carnitine deficiency (PCD) is a genetic disorder caused by decreased or absent organic cation transporter type 2 (OCTN2) carnitine transporter activity, resulting in low serum carnitine levels and decreased carnitine accumulation inside cells. In early life, PCD is usually diagnosed as a metabolic decompensation, presenting as hypoketotic hypoglycemia, Reye syndrome, or sudden infant death; in childhood, PCD presents with skeletal or cardiac myopathy. However, the clinical presentation of PCD characterized by autism spectrum disorder (ASD) with intellectual disability (ID) has seldom been reported in the literature. In this report, we describe the clinical features of a seven-year-old girl diagnosed with PCD who presented atypical features of the disease, including a developmental delay involving language skills, concentration, and attention span, as well as autistic features and brain alterations apparent in magnetic resonance imaging. We aim to highlight the difficulties related to the diagnostic and therapeutic approaches used to diagnose such patients. The case reported here presented typical signs of PCD, including frequent episodes of hypoglycemia, generalized muscle weakness, decreased muscle mass, and physical growth deficits. A molecular genetic study confirmed the definitive diagnosis of the disease (c.1345T>G (p.Y449D)) in gene SLC22A5, located in exon 8. PCD can be accompanied by less common clinical signs, which may delay its diagnosis because the resulting global clinical picture can closely resemble other metabolic disorders. In this case, the patient was prescribed a carnitine-enriched diet, as well as oral carnitine at a dose of 100 mg/kg/day. PCD has a better prognosis if it is diagnosed and treated early; however, a high level of clinical suspicion is required for its timely and accurate diagnosis.
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Affiliation(s)
- José Guevara-Campos
- "Felipe Guevara Rojas" Hospital, Pediatrics Service, University of Oriente, El Tigre-Anzoátegui 6034, Venezuela.
| | - Lucía González-Guevara
- "Felipe Guevara Rojas" Hospital, Epilepsy and Encephalography Unit, El Tigre-Anzoátegui 6034, Venezuela.
| | | | - Omar Cauli
- Department of Nursing, University of Valencia, 46010 Valencia, Spain.
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Chen S, Hu Y, Huang Y, Nan Y, Zhou X, Chen S, Lin J, Lin Z. A newborn with seizures born to a mother diagnosed with primary carnitine deficiency. BMC Pediatr 2019; 19:79. [PMID: 30885166 PMCID: PMC6421665 DOI: 10.1186/s12887-019-1452-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 03/07/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Maternofetal carnitine transport through the placenta is the main route of fetal carnitine uptake. Decreased free carnitine levels discovered by newborn screening has identified many asymptomatic adult women with systemic primary carnitine deficiency (PCD). Here, we presented amplitude integrated electroencephalogram (aEEG) and magnetic resonance imaging (MRI) findings from a neonate with epilepsy whose mother was carnitine deficient. CASE PRESENTATION A one-day-old female newborn was admitted after experiencing seizures for half a day; status epilepticus was found on the continuous normal voltage background pattern with immature sleep-wake cycling during aEEG monitoring. On T1-weighted, T2-weighted, FLAIR, and DWI head MRI, there were various degrees of hyperintense signals and diffusion restrictions in the deep white matter of the right hemisphere. Tandem mass spectrometry discovered carnitine deficiency on the second day, which elevated to normal by the 9th day before L-carnitine supplementation was started. The patient was treated with phenobarbital after admission. No further seizures were noted by day 5. It was confirmed that the patient's mother had a low level of serum-free carnitine. Gene analyses revealed that the newborn had heterozygote mutations on c.1400C > G of the SLC22A5 gene, and her mother had homozygous mutations on c.1400C > G. The patient had a good outcome at the 8-month follow up. CONCLUSIONS Maternal carnitine deficiency that occurs during the perinatal period may manifest as secondary epilepsy with cerebral injury in neonates. The short-term neurodevelopmental outcomes were good. Early diagnosis of asymptomatic PCD in female patients can provide guidance for future pregnancies.
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Affiliation(s)
- Si Chen
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
| | - Yingying Hu
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
| | - Yumei Huang
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
| | - Yan Nan
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
| | - Xiaojian Zhou
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
| | - Shangqin Chen
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
| | - Jin Lin
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
- Kravis Children’s Hospital and Department of Pediatrics, The Icahn School of Medicine at Mount Sinai, New York, NY 10029 USA
| | - Zhenlang Lin
- Department of Neonatology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Zhejiang, 325027 Wenzhou China
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37
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Pennisi EM, Garibaldi M, Antonini G. Lipid Myopathies. J Clin Med 2018; 7:E472. [PMID: 30477112 PMCID: PMC6306737 DOI: 10.3390/jcm7120472] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 02/06/2023] Open
Abstract
Disorders of lipid metabolism affect several tissues, including skeletal and cardiac muscle tissues. Lipid myopathies (LM) are rare multi-systemic diseases, which most often are due to genetic defects. Clinically, LM can have acute or chronic clinical presentation. Disease onset can occur in all ages, from early stages of life to late-adult onset, showing with a wide spectrum of clinical symptoms. Muscular involvement can be fluctuant or stable and can manifest as fatigue, exercise intolerance and muscular weakness. Muscular atrophy is rarely present. Acute muscular exacerbations, resulting in rhabdomyolysis crisis are triggered by several factors. Several classifications of lipid myopathies have been proposed, based on clinical involvement, biochemical defect or histopathological findings. Herein, we propose a full revision of all the main clinical entities of lipid metabolism disorders with a muscle involvement, also including some those disorders of fatty acid oxidation (FAO) with muscular symptoms not included among previous lipid myopathies classifications.
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Affiliation(s)
- Elena Maria Pennisi
- Unit of Neuromuscular Disorders, Neurology, San Filippo Neri Hospital, 00135 Rome, Italy.
| | - Matteo Garibaldi
- Unit of Neuromuscular Diseases, Department of Neurology, Mental Health and Sensory Organs (NESMOS), SAPIENZA University of Rome, Sant' Andrea Hospital, 00189 Rome, Italy.
| | - Giovanni Antonini
- Unit of Neuromuscular Diseases, Department of Neurology, Mental Health and Sensory Organs (NESMOS), SAPIENZA University of Rome, Sant' Andrea Hospital, 00189 Rome, Italy.
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38
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Vasiljevski ER, Summers MA, Little DG, Schindeler A. Lipid storage myopathies: Current treatments and future directions. Prog Lipid Res 2018; 72:1-17. [PMID: 30099045 DOI: 10.1016/j.plipres.2018.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/20/2018] [Accepted: 08/06/2018] [Indexed: 10/28/2022]
Abstract
Lipid storage myopathies (LSMs) are a heterogeneous group of genetic disorders that present with abnormal lipid storage in multiple body organs, typically muscle. Patients can clinically present with cardiomyopathy, skeletal muscle weakness, myalgia, and extreme fatigue. An early diagnosis is crucial, as some LSMs can be managed by simple nutraceutical supplementation. For example, high dosage l-carnitine is an effective intervention for patients with Primary Carnitine Deficiency (PCD). This review discusses the clinical features and management practices of PCD as well as Neutral Lipid Storage Disease (NLSD) and Multiple Acyl-CoA Dehydrogenase Deficiency (MADD). We provide a detailed summary of current clinical management strategies, highlighting issues of high-risk contraindicated treatments with case study examples not previously reviewed. Additionally, we outline current preclinical studies providing disease mechanistic insight. Lastly, we propose that a number of other conditions involving lipid metabolic dysfunction that are not classified as LSMs may share common features. These include Neurofibromatosis Type 1 (NF1) and autoimmune myopathies, including Polymyositis (PM), Dermatomyositis (DM), and Inclusion Body Myositis (IBM).
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Affiliation(s)
- Emily R Vasiljevski
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Matthew A Summers
- Bone Biology Division, The Garvan Institute of Medical Research, Darlinghurst, NSW, Australia; St Vincent's Clinical School, University of New South Wales, Faculty of Medicine, Sydney, NSW, Australia
| | - David G Little
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Aaron Schindeler
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia.
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Kou L, Sun R, Ganapathy V, Yao Q, Chen R. Recent advances in drug delivery via the organic cation/carnitine transporter 2 (OCTN2/SLC22A5). Expert Opin Ther Targets 2018; 22:715-726. [PMID: 30016594 DOI: 10.1080/14728222.2018.1502273] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Transporters in the plasma membrane have been exploited successfully for the delivery of drugs in the form of prodrugs and nanoparticles. Organic cation/carnitine transporter 2 (OCTN2, SLC22A5) has emerged as a viable target for drug delivery. OCTN2 is a Na+-dependent high-affinity transporter for L-carnitine and a Na+-independent transporter for organic cations. OCTN2 is expressed in the blood-brain barrier, heart, liver, kidney, intestinal tract and placenta and plays an essential role in L-carnitine homeostasis in the body. Areas covered: In recent years, several studies have been reported in the literature describing the utility of OCTN2 to enhance the delivery of drugs, prodrugs and nanoparticles. Here we summarize the salient features of OCTN2 in terms of its role in the cellular uptake of its physiological substrate L-carnitine in physiological and pathological context; the structural requirements for recognition and the recent advances in OCTN2-targeted drug delivery systems, including prodrugs and nanoparticles, are discussed. Expert opinion: This transporter has great potential to be utilized as a target for drug delivery to improve oral absorption of drugs in the intestinal tract. It also has potential to facilitate the transfer of drugs across the biological barriers such as the blood-brain barrier, blood-retinal barrier, and maternal-fetal barrier.
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Affiliation(s)
- Longfa Kou
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Rui Sun
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Vadivel Ganapathy
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China.,b Department of Cell Biology and Biochemistry , School of Medicine, Texas Tech University Health Sciences Center , Lubbock , TX , USA
| | - Qing Yao
- c School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Ruijie Chen
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
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40
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Echaniz-Laguna A, Biancalana V, Gaignard P, Chanson JB. Primary carnitine deficiency in a 57-year-old patient with recurrent exertional rhabdomyolysis. BMJ Case Rep 2018; 2018:bcr-2018-224272. [PMID: 29895548 DOI: 10.1136/bcr-2018-224272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Rhabdomyolysis is an emergency requiring rapid diagnosis and suitable aetiological treatment. We describe the case of a 57-year-old man with recurrent exertional rhabdomyolysis who was diagnosed with systemic primary carnitine deficiency (SPCD). Clinical examination was normal, creatine kinase levels were elevated, plasma free carnitine concentration was mildly decreased, muscle biopsy demonstrated lipid accumulation, carnitine uptake in cultured fibroblasts was decreased and genetic analysis identified a homozygous pathologic c.1181_1183del in the SLC22A5 gene. Rhabdomyolysis did not recur after treatment with oral L-carnitine was introduced. SPCD is a rare autosomal recessive disorder of carnitine transportation usually manifesting as an infantile (hepatic) or a childhood myopathic (cardiac) condition and rarely affecting adults. Our case indicates that SPCD should be considered in the aetiological evaluation of adult patients with recurrent exertional rhabdomyolysis, even in the absence of myopathy and cardiomyopathy.
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Affiliation(s)
| | - Valérie Biancalana
- Laboratoire de Diagnostic Génétique, Hopitaux universitaires de Strasbourg, Strasbourg, France.,Physiopathologie des maladies neuromusculaires, Institut de Genetique et de Biologie Moleculaire et Cellulaire, Illkirch, France
| | - Pauline Gaignard
- Service de Biochimie, Hopital Bicetre, Le Kremlin-Bicetre, France
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41
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Alghamdi A, Almalki H, Shawli A, Waggass R, Hakami F. A case of atypical systemic primary carnitine deficiency in Saudi Arabia. Pediatr Rep 2018; 10:7705. [PMID: 30069296 PMCID: PMC6050471 DOI: 10.4081/pr.2018.7705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/24/2018] [Indexed: 11/23/2022] Open
Abstract
Systemic primary carnitine deficiency (SPCD) is an autosomal recessive inborn error of fatty acid metabolism caused by a defect in the transporter responsible for moving carnitine across plasma membrane. The clinical features of SPCD vary widely based on the age of onset and organs involved. During infancy, patients might show episodes of hypoketotic hypoglycemia, hepatomegaly, elevated transaminases, and hyperammonemia. Skeletal myopathy, elevated creatine kinase, and cardiomyopathy are the main manifestations in children with SPCD, while in adults, the disorder is usually manifested as cardiomyopathy, arrhythmias, or fatigability. Here, we report a 5-year-old boy with SPCD that presented as dilated cardiomyopathy with atypical features, such as anemia, respiratory distress, and proximal muscle weakness. This report supports considering carnitine deficiency treatment in the work-up of unexplained pediatric dilated cardiomyopathy.
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Affiliation(s)
- Abdulrahman Alghamdi
- King Abdullah International Medical Research Center
- King Saud bin Abdulaziz University for Health Sciences
| | - Hani Almalki
- King Abdullah International Medical Research Center
- King Saud bin Abdulaziz University for Health Sciences
| | - Aiman Shawli
- King Abdullah International Medical Research Center
- King Saud bin Abdulaziz University for Health Sciences
- Department of Pediatrics
| | - Rahaf Waggass
- King Abdullah International Medical Research Center
- King Saud bin Abdulaziz University for Health Sciences
- King Faisal Cardiac Center
| | - Fahad Hakami
- King Abdullah International Medical Research Center
- King Saud bin Abdulaziz University for Health Sciences
- Molecular Medicine Section, Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City-WR, Jeddah, Saudi Arabia
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42
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Knottnerus SJG, Bleeker JC, Wüst RCI, Ferdinandusse S, IJlst L, Wijburg FA, Wanders RJA, Visser G, Houtkooper RH. Disorders of mitochondrial long-chain fatty acid oxidation and the carnitine shuttle. Rev Endocr Metab Disord 2018; 19:93-106. [PMID: 29926323 PMCID: PMC6208583 DOI: 10.1007/s11154-018-9448-1] [Citation(s) in RCA: 196] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial fatty acid oxidation is an essential pathway for energy production, especially during prolonged fasting and sub-maximal exercise. Long-chain fatty acids are the most abundant fatty acids in the human diet and in body stores, and more than 15 enzymes are involved in long-chain fatty acid oxidation. Pathogenic mutations in genes encoding these enzymes result in a long-chain fatty acid oxidation disorder in which the energy homeostasis is compromised and long-chain acylcarnitines accumulate. Symptoms arise or exacerbate during catabolic situations, such as fasting, illness and (endurance) exercise. The clinical spectrum is very heterogeneous, ranging from hypoketotic hypoglycemia, liver dysfunction, rhabdomyolysis, cardiomyopathy and early demise. With the introduction of several of the long-chain fatty acid oxidation disorders (lcFAOD) in newborn screening panels, also asymptomatic individuals with a lcFAOD are identified. However, despite early diagnosis and dietary therapy, a significant number of patients still develop symptoms emphasizing the need for individualized treatment strategies. This review aims to function as a comprehensive reference for clinical and laboratory findings for clinicians who are confronted with pediatric and adult patients with a possible diagnosis of a lcFAOD.
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Affiliation(s)
- Suzan J G Knottnerus
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Jeannette C Bleeker
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Rob C I Wüst
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Lodewijk IJlst
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Frits A Wijburg
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Gepke Visser
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands.
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
| | - Riekelt H Houtkooper
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
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Frigeni M, Balakrishnan B, Yin X, Calderon FRO, Mao R, Pasquali M, Longo N. Functional and molecular studies in primary carnitine deficiency. Hum Mutat 2017; 38:1684-1699. [PMID: 28841266 DOI: 10.1002/humu.23315] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/13/2017] [Accepted: 08/17/2017] [Indexed: 12/30/2022]
Abstract
Primary carnitine deficiency is caused by a defect in the OCTN2 carnitine transporter encoded by the SLC22A5 gene. It can cause hypoketotic hypoglycemia or cardiomyopathy in children, and sudden death in children and adults. Fibroblasts from affected patients have reduced carnitine transport. We evaluated carnitine transport in fibroblasts from 358 subjects referred for possible carnitine deficiency. Carnitine transport was reduced to 20% or less of normal in fibroblasts of 140 out of 358 subjects. Sequencing of the 10 exons and flanking regions of the SLC22A5 gene in 95 out of 140 subjects identified causative variants in 84% of the alleles. The missense variants identified in our patients and others previously reported (n = 92) were expressed in CHO cells. Carnitine transport was impaired by 73 out of 92 variants expressed. Prediction algorithms (Polyphen-2, SIFT) correctly predicted the functional effects of expressed variants in about 80% of cases. These results indicate that mutations in the coding region of the SLC22A5 gene cannot be identified in about 16% of the alleles causing primary carnitine deficiency. Prediction algorithms failed to determine the functional effects of amino acid substitutions in this transmembrane protein in about 20% of cases. Therefore, functional studies in fibroblasts remain the best strategy to confirm or exclude a diagnosis of primary carnitine deficiency.
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Affiliation(s)
- Marta Frigeni
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, Utah
| | - Bijina Balakrishnan
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, Utah
| | - Xue Yin
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, Utah
| | - Fernanda R O Calderon
- ARUP Institute for Clinical and Experimental Pathology®, ARUP Laboratories, Salt Lake City, Utah.,Department of Pathology, University of Utah, Salt Lake City, Utah
| | - Rong Mao
- ARUP Institute for Clinical and Experimental Pathology®, ARUP Laboratories, Salt Lake City, Utah.,Department of Pathology, University of Utah, Salt Lake City, Utah
| | - Marzia Pasquali
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, Utah.,ARUP Institute for Clinical and Experimental Pathology®, ARUP Laboratories, Salt Lake City, Utah.,Department of Pathology, University of Utah, Salt Lake City, Utah
| | - Nicola Longo
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, Utah.,ARUP Institute for Clinical and Experimental Pathology®, ARUP Laboratories, Salt Lake City, Utah.,Department of Pathology, University of Utah, Salt Lake City, Utah
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44
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Tight junction protein ZO-1 controls organic cation/carnitine transporter OCTN2 (SLC22A5) in a protein kinase C-dependent way. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:797-805. [PMID: 28257821 DOI: 10.1016/j.bbamcr.2017.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/07/2017] [Accepted: 02/27/2017] [Indexed: 12/20/2022]
Abstract
OCTN2 (SLC22A5) is an organic cation/carnitine transporter belonging to the solute carrier transporters (SLC) family. OCTN2 is ubiquitously expressed and its presence was shown in various brain cells, including the endothelial cells forming blood-brain barrier, where it was mainly detected at abluminal membrane and in proximity of tight junctions (TJ). Since OCTN2 contains a PDZ-binding domain, the present study was focused on a possible role of transporter interaction with a TJ-associated protein ZO-1, containing PDZ domains and detected in rat Octn2 proteome. We showed previously that activation of protein kinase C (PKC) in rat astrocytes regulates Octn2 surface presence and activity. Regulation of a wild type Octn2 and its deletion mutant without a PDZ binding motif were studied in heterologous expression system in HEK293 cells. Plasma membrane presence of overexpressed Octn2 did not depend on either PKC activation or presence of PDZ-binding motif, anyhow, as assayed in proximity ligation assay, the truncation of PDZ binding motif resulted in a strongly diminished Octn2/ZO-1 interaction and in a decreased transporter activity. The same effects on Octn2 activity were detected upon PKC activation, what correlated with ZO-1 phosphorylation. It is postulated that ZO-1, when not phosphorylated by PKC, keeps Octn2 in an active state, while elimination of this binding in ΔPDZ mutant or after ZO-1 phosphorylation leads to diminution of Octn2 activity.
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45
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Frigeni M, Iacobazzi F, Yin X, Longo N. Wide tolerance to amino acids substitutions in the OCTN1 ergothioneine transporter. Biochim Biophys Acta Gen Subj 2016; 1860:1334-42. [PMID: 26994919 DOI: 10.1016/j.bbagen.2016.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 02/24/2016] [Accepted: 03/15/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Organic cation transporters transfer solutes with a positive charge across the plasma membrane. The novel organic cation transporter 1 (OCTN1) and 2 (OCTN2) transport ergothioneine and carnitine, respectively. Mutations in the SLC22A5 gene encoding OCTN2 cause primary carnitine deficiency, a recessive disorders resulting in low carnitine levels and defective fatty acid oxidation. Variations in the SLC22A4 gene encoding OCTN1 are associated with rheumatoid arthritis and Crohn disease. METHODS Here we evaluate the functional properties of the OCTN1 transporter using chimeric transporters constructed by fusing different portion of the OCTN1 and OCTN2 cDNAs. Their relative abundance and subcellular distribution was evaluated through western blot analysis and confocal microscopy. RESULTS Substitutions of the C-terminal portion of OCTN1 with the correspondent residues of OCTN2 generated chimeric OCTN transporters more active than wild-type OCTN1 in transporting ergothioneine. Additional single amino acid substitutions introduced in chimeric OCTN transporters further increased ergothioneine transport activity. Kinetic analysis indicated that increased transport activity was due to an increased V(max), with modest changes in K(m) toward ergothioneine. CONCLUSIONS Our results indicate that the OCTN1 transporter is tolerant to extensive amino acid substitutions. This is in sharp contrast to the OCTN2 carnitine transporter that has been selected for high functional activity through evolution, with almost all substitutions reducing carnitine transport activity. GENERAL SIGNIFICANCE The widespread tolerance of OCTN1 to amino acid substitutions suggests that the corresponding SLC22A4 gene may have derived from a recent duplication of the SLC22A5 gene and might not yet have a defined physiological role.
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Affiliation(s)
- Marta Frigeni
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States
| | - Francesco Iacobazzi
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States; Department of Basic Medical Sciences, University of Bari, Policlinico, I-70124 Bari, Italy
| | - Xue Yin
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States
| | - Nicola Longo
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States.
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Longo N, Frigeni M, Pasquali M. Carnitine transport and fatty acid oxidation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2422-35. [PMID: 26828774 DOI: 10.1016/j.bbamcr.2016.01.023] [Citation(s) in RCA: 480] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 12/14/2022]
Abstract
Carnitine is essential for the transfer of long-chain fatty acids across the inner mitochondrial membrane for subsequent β-oxidation. It can be synthesized by the body or assumed with the diet from meat and dairy products. Defects in carnitine biosynthesis do not routinely result in low plasma carnitine levels. Carnitine is accumulated by the cells and retained by kidneys using OCTN2, a high affinity organic cation transporter specific for carnitine. Defects in the OCTN2 carnitine transporter results in autosomal recessive primary carnitine deficiency characterized by decreased intracellular carnitine accumulation, increased losses of carnitine in the urine, and low serum carnitine levels. Patients can present early in life with hypoketotic hypoglycemia and hepatic encephalopathy, or later in life with skeletal and cardiac myopathy or sudden death from cardiac arrhythmia, usually triggered by fasting or catabolic state. This disease responds to oral carnitine that, in pharmacological doses, enters cells using the amino acid transporter B(0,+). Primary carnitine deficiency can be suspected from the clinical presentation or identified by low levels of free carnitine (C0) in the newborn screening. Some adult patients have been diagnosed following the birth of an unaffected child with very low carnitine levels in the newborn screening. The diagnosis is confirmed by measuring low carnitine uptake in the patients' fibroblasts or by DNA sequencing of the SLC22A5 gene encoding the OCTN2 carnitine transporter. Some mutations are specific for certain ethnic backgrounds, but the majority are private and identified only in individual families. Although the genotype usually does not correlate with metabolic or cardiac involvement in primary carnitine deficiency, patients presenting as adults tend to have at least one missense mutation retaining residual activity. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA; Department of Pathology, University of Utah, and ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT, USA.
| | - Marta Frigeni
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Marzia Pasquali
- Department of Pathology, University of Utah, and ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT, USA
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Abstract
Carnitine is essential for the transfer of long-chain fatty acids from the cytosol into mitochondria for subsequent β-oxidation. A lack of carnitine results in impaired energy production from long-chain fatty acids, especially during periods of fasting or stress. Primary carnitine deficiency (PCD) is an autosomal recessive disorder of mitochondrial β-oxidation resulting from defective carnitine transport and is one of the rare treatable etiologies of metabolic cardiomyopathies. Patients affected with the disease may present with acute metabolic decompensation during infancy or with severe cardiomyopathy in childhood. Early recognition of the disease and treatment with L-carnitine may be life-saving. In this review article, the pathophysiology, clinical presentation, diagnosis, treatment and prognosis of PCD are discussed, with a focus on cardiac involvements.
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Affiliation(s)
- Lijun Fu
- Department of Cardiology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Meirong Huang
- Department of Cardiology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Shubao Chen
- Department of Cardiology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Residual OCTN2 transporter activity, carnitine levels and symptoms correlate in patients with primary carnitine deficiency. Mol Genet Metab Rep 2014; 1:241-248. [PMID: 27896095 PMCID: PMC5121291 DOI: 10.1016/j.ymgmr.2014.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 04/25/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The prevalence of primary carnitine deficiency (PCD) in the Faroe Islands is the highest reported in the world (1:300). Serious symptoms related to PCD, e.g. sudden death, have previously only been associated to the c.95A > G/c.95A > G genotype in the Faroe Islands. We report and characterize novel mutations associated with PCD in the Faroese population and report and compare free carnitine levels and OCTN2 transport activities measured in fibroblasts from PCD patients with different genotypes. METHODS Genetic analyses were used to identify novel mutations, and carnitine uptake analyses in cultured skin fibroblasts from selected patients were used to examine residual OCTN2 transporter activities of the various genotypes. RESULTS Four different mutations, including the unpublished c.131C > T (p.A44V), the novel splice mutation c.825-52G > A and a novel risk-haplotype (RH) were identified in the Faroese population. The two most prevalent genotypes were c.95A > G/RH (1:600) and c.95A > G/c.95A > G (1:1300). Patients homozygous for the c.95A > G mutation had both the significantly (p < 0.01) lowest mean free carnitine level at 2.03 (SD 0.66) μmol/L and lowest residual OCTN2 transporter activity (4% of normal). There was a significant positive correlation between free carnitine levels and residual OCTN2 transporter activities in PCD patients (R2 = 0.430, p < 0.01). CONCLUSION There was a significant positive correlation between carnitine levels and OCTN2 transporter activities. The c.95A > G/c.95A > G genotype had the significantly lowest mean free carnitine level and residual OCTN2 transporter activity.
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Pasquali M, Longo N. Response to chen et Al.: carnitine uptake defect (primary carnitine deficiency): risk in genotype-phenotype correlation. Hum Mutat 2013; 34:656. [PMID: 23520116 DOI: 10.1002/humu.22285] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 01/22/2013] [Indexed: 11/09/2022]
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Chen YC, Chien YH, Chen PW, Leung-Sang Tang N, Chiu PC, Hwu WL, Lee NC. Carnitine uptake defect (primary carnitine deficiency): risk in genotype-phenotype correlation. Hum Mutat 2013; 34:655. [PMID: 23520115 DOI: 10.1002/humu.22286] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 12/11/2012] [Indexed: 11/11/2022]
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