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Jing J, Zhang C, Du S, Tan X, Yue X, Qiao D. Sudden death with cardiac involvement in a neonate with carnitine-acylcarnitine translocase deficiency. Cardiovasc Pathol 2024; 70:107630. [PMID: 38490313 DOI: 10.1016/j.carpath.2024.107630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/22/2024] [Accepted: 03/05/2024] [Indexed: 03/17/2024] Open
Abstract
A female neonate born with normal Apgar scores at 38+2 weeks of gestational age unexpectedly passed away within less than 30 hours after birth. The situation mirrored her brother's earlier demise within 24 hours post-delivery, suggesting a possible genetic disorder. Gross examination revealed widespread cyanosis and distinct yellowish changes on the cardiac ventricles. Histopathological examination disclosed lipid accumulation in the liver, heart, and kidneys. Tandem mass spectrometry detected elevated levels of 10 amino acids and 14 carnitines in cardiac blood. Trio-whole genome sequencing (Trio-WGS) identified the SLC25A20 c.199-10T>G mutation associated with carnitine-acylcarnitine translocase disease (CACTD), a type of fatty acid oxidation disorders (FAODs) with a potential for sudden death. Further validation of gene expression confirmed the functional deficiency of SLC25A20, ultimately diagnosing CACTD as the underlying cause of the neonate's demise. This case highlights the importance of prenatal metabolic and genetic screening for prospective parents and emphasizes the need for forensic doctors to integrate metabolomic and genomic investigations into autopsies for suspected inherited metabolic diseases.
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Affiliation(s)
- Jiayu Jing
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Cui Zhang
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Sihao Du
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Xiaohui Tan
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Xia Yue
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Dongfang Qiao
- School of Forensic Medicine, Southern Medical University, Guangzhou, China.
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Zhang Q, Feng X, Wang X, Liu F, Zhou B, Zhang C, Wang Y, Shi J, Hao S, Hui L, Yi B. [Clinical and genetic analysis of two pedigrees affected with Carnitine-acylcarnitine translocase deficiency due to variant of SLC25A20 gene]. Zhonghua Yi Xue Yi Chuan Xue Za Zhi 2024; 41:467-472. [PMID: 38565514 DOI: 10.3760/cma.j.cn511374-20220721-00482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
OBJECTIVE To analyze the clinical phenotype and genotypes of two children with Carnitine-acylcarnitine translocase deficiency (CACTD). METHODS Two children diagnosed with CACTD at the Gansu Provincial Maternal and Child Health Care Hospital respectively on January 3 and November 19, 2018 were selected as the study subjects. Trio-whole exome sequencing (trio-WES) was carried out, and candidate variants were validated through Sanger sequencing and pathogenicity analysis. RESULTS Both children were males and had manifested mainly with hypoglycemia. Trio-WES and Sanger sequencing showed that child 1 had harbored compound heterozygous variants of the SLC25A20 gene, namely c.49G>C (p.Gly17Arg) and c.106-2A>G, which were inherited from his father and mother, respectively. Child 2 had harbored homozygous c.199-10T>G variants of the SLC25A20 gene, which were inherited from both of his parents. Among these, the c.106-2A>G and c.49G>C variants were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.49G>C (p.Gly17Arg), c.106-2A>G, and c.199-10T>G variants were classified as likely pathogenic (PM2_supporting+PP3+PM3_strong+PP4), pathogenic (PVS1+PM2_supporting+PM5+PP3), and pathogenic (PVS1+PM2_supporting+PP3+PP5), respectively. CONCLUSION Combined with their clinical phenotype and genetic analysis, both children were diagnosed with CACTD. Above finding has provided a basis for their treatment as well as genetic counseling and prenatal diagnosis for their families.
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Affiliation(s)
- Qinghua Zhang
- Medical Genetic Center, Gansu Provincial Maternal and Child Health Care Hospital (Gansu Province Central Hospital), Lanzhou, Gansu 730050, China.
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Ryder B, Inbar-Feigenberg M, Glamuzina E, Halligan R, Vara R, Elliot A, Coman D, Minto T, Lewis K, Schiff M, Vijay S, Akroyd R, Thompson S, MacDonald A, Woodward AJM, Gribben JEL, Grunewald S, Belaramani K, Hall M, van der Haak N, Devanapalli B, Tolun AA, Wilson C, Bhattacharya K. New insights into carnitine-acylcarnitine translocase deficiency from 23 cases: Management challenges and potential therapeutic approaches. J Inherit Metab Dis 2021; 44:903-915. [PMID: 33634872 DOI: 10.1002/jimd.12371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 12/22/2022]
Abstract
Carnitine acyl-carnitine translocase deficiency (CACTD) is a rare autosomal recessive disorder of mitochondrial long-chain fatty-acid transport. Most patients present in the first 2 days of life, with hypoketotic hypoglycaemia, hyperammonaemia, cardiomyopathy or arrhythmia, hepatomegaly and elevated liver enzymes. Multi-centre international retrospective chart review of clinical presentation, biochemistry, treatment modalities including diet, subsequent complications, and mode of death of all patients. Twenty-three patients from nine tertiary metabolic units were identified. Seven attenuated patients of Pakistani heritage, six of these homozygous c.82G>T, had later onset manifestations and long-term survival without chronic hyperammonemia. Of the 16 classical cases, 15 had cardiac involvement at presentation comprising cardiac arrhythmias (9/15), cardiac arrest (7/15), and cardiac hypertrophy (9/15). Where recorded, ammonia levels were elevated in all but one severe case (13/14 measured) and 14/16 had hypoglycaemia. Nine classical patients survived longer-term-most with feeding difficulties and cognitive delay. Hyperammonaemia appears refractory to ammonia scavenger treatment and carglumic acid, but responds well to high glucose delivery during acute metabolic crises. High-energy intake seems necessary to prevent decompensation. Anaplerosis utilising therapeutic d,l-3-hydroxybutyrate, Triheptanoin and increased protein intake, appeared to improve chronic hyperammonemia and metabolic stability where trialled in individual cases. CACTD is a rare disorder of fatty acid oxidation with a preponderance to severe cardiac dysfunction. Long-term survival is possible in classical early-onset cases with long-chain fat restriction, judicious use of glucose infusions, and medium chain triglyceride supplementation. Adjunctive therapies supporting anaplerosis may improve longer-term outcomes.
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Affiliation(s)
- Bryony Ryder
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
- National Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
| | - Michal Inbar-Feigenberg
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Emma Glamuzina
- National Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
| | - Rebecca Halligan
- Department of Inherited Metabolic Disorders, Birmingham Women's and Children's Hospital Foundation Trust, Birmingham, UK
- Department of Metabolic Medicine, Evelina Children's Hospital, London, UK
| | - Roshni Vara
- Department of Metabolic Medicine, Evelina Children's Hospital, London, UK
| | - Aoife Elliot
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, Brisbane, QLD, Australia
| | - David Coman
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, Brisbane, QLD, Australia
- School of Medicine University of Queensland and Griffith University, Brisbane, Queensland, Australia
| | - Tahlee Minto
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, Brisbane, QLD, Australia
| | - Katherine Lewis
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, Brisbane, QLD, Australia
| | - Manuel Schiff
- Reference Centre for Inherited Metabolic Diseases, AP-HP, Necker University Hospital, University of Paris, Paris, France
- INSERM U1163, Institut Imagine, Paris, France
| | - Suresh Vijay
- Department of Inherited Metabolic Disorders, Birmingham Women's and Children's Hospital Foundation Trust, Birmingham, UK
| | - Rhonda Akroyd
- National Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
| | - Sue Thompson
- Department of Metabolic Genetics, Sydney Children's Hospitals' Network NSW, Sydney, New South Wales, Australia
- Faculty of Health and Medical Science, University of Sydney, Sydney, New South Wales, Australia
| | - Anita MacDonald
- Department of Inherited Metabolic Disorders, Birmingham Women's and Children's Hospital Foundation Trust, Birmingham, UK
| | - Abigail J M Woodward
- Department of Nutrition & Dietetics, Evelina London Children's Hospital, London, UK
| | - Joanne E L Gribben
- Department of Nutrition & Dietetics, Evelina London Children's Hospital, London, UK
| | - Stephanie Grunewald
- Metabolic Medicine Department, Great Ormond Street Hospital, Institute of Child Health University College London, NIHR Biomedical Research Centre, London, UK
| | - Kiran Belaramani
- Department of Metabolic Medicine, Hong Kong Children's Hospital, Ngau Tau Kok, Hong Kong
| | - Madeleine Hall
- Departments of Metabolic Medicine & Nutrition, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Natalie van der Haak
- Departments of Metabolic Medicine & Nutrition, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Beena Devanapalli
- Department of Metabolic Genetics, Sydney Children's Hospitals' Network NSW, Sydney, New South Wales, Australia
| | - Adviye Ayper Tolun
- Department of Metabolic Genetics, Sydney Children's Hospitals' Network NSW, Sydney, New South Wales, Australia
| | - Callum Wilson
- National Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
| | - Kaustuv Bhattacharya
- Department of Metabolic Genetics, Sydney Children's Hospitals' Network NSW, Sydney, New South Wales, Australia
- Faculty of Health and Medical Science, University of Sydney, Sydney, New South Wales, Australia
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Yan HM, Hu H, Ahmed A, Feng BB, Liu J, Jia ZJ, Wang H. Carnitine-acylcarnitine translocase deficiency with c.199-10 T>G and novel c.1A>G mutation: Two case reports and brief literature review. Medicine (Baltimore) 2017; 96:e8549. [PMID: 29137068 PMCID: PMC5690761 DOI: 10.1097/md.0000000000008549] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
RATIONALE Carnitine-acylcarnitine translocate deficiency (CACTD) is a rare and life-threatening, autosomal recessive disorder of fatty acid β-oxidation characterized by hypoketotic hypoglycemia, hyperammonemia, cardiomyopathy, liver dysfunction, and muscle weakness; culminating in early death. To date, CACTD cases screened from the Chinese mainland population, especially patient with compound heterozygote with c.199-10T>G and a novel c.1A>G mutation in the SLC25A20 gene has never been described. PATIENT CONCERNS Herein, we report 2 neonatal cases of CACTD identified from the mainland China. These 2 patients were presented with severe metabolic crisis and their clinical conditions deteriorate rapidly and both died of cardiorespiratory collapse in the first week of life. We present the clinical and biochemical features of 2 probands and a brief literature review of previously reported CACTD cases with the c.199-10T>G mutation. DIAGNOSES The acylcarnitine profiles by tandem-mass-spectrometry and the mutation analysis of SLC25A20 gene confirmed the diagnosis of CACTD in both patients. Mutation analysis demonstrated that patient No. 1 was homozygous for c.199-10T>G mutation, while patient No. 2 was a compound heterozygote for 2 mutations, a maternally-inherited c.199-10T>G and a paternally-inherited, novel c.1A>G mutation. INTERVENTIONS Both patients were treated with an aggressive treatment regimen include high glucose and arginine infusion, respiratory, and circulatory support. OUTCOMES The first proband died 3 days after delivery due to sudden cardiac arrest. The second patient's clinical condition, at one time, was improved by high glucose infusion, intravenous arginine, and circulatory support. However, the patient failed to wean from mechanical ventilation. Unfortunately, her parents refused further treatment due to fear of financial burdens. The patient died of congestive heart failure in the 6th day of life. LESSONS We report the first 2 cases of CACTD identified from the mainland China. Apart from a founder mutation c.199-10T>G, we identified a novel c.1A>G mutation. Patients with CACTD with a genotype of c.199-10T>G mutation usually presents with a severe clinical phenotype. Early recognition and appropriate treatment is crucial in this highly lethal disorder. This case series highlights the importance of screening for metabolic diseases including CACTD in cases of sudden infant death and unexplained abrupt clinical deterioration in the early neonatal period.
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Affiliation(s)
- Hui-ming Yan
- Newborn Screening Center of Hunan Province, The Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan, China
| | - Hao Hu
- Newborn Screening Center of Hunan Province, The Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan, China
| | - Aisha Ahmed
- Minneapolis Heart Institute Foundation, Minneapolis, Minnesota, USA
| | - Bing-bing Feng
- Newborn Screening Center of Hunan Province, The Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan, China
| | - Jing Liu
- Newborn Screening Center of Hunan Province, The Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan, China
| | - Zheng-jun Jia
- Newborn Screening Center of Hunan Province, The Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan, China
| | - Hua Wang
- Newborn Screening Center of Hunan Province, The Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan, China
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Morita M, Matsumoto S, Okazaki A, Tomita K, Watanabe S, Kawaguchi K, Minato D, Matsuya Y, Shimozawa N, Imanaka T. A novel method for determining peroxisomal fatty acid β-oxidation. J Inherit Metab Dis 2016; 39:725-731. [PMID: 27324171 DOI: 10.1007/s10545-016-9952-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/23/2016] [Accepted: 06/01/2016] [Indexed: 10/21/2022]
Abstract
The purpose of this study is to establish an assay method to screen for chemical compounds that stimulate peroxisomal fatty acid β-oxidation activity in X-linked adrenoleukodystropy (X-ALD) fibroblasts. In this investigation, we used 12-(1-pyrene)dodecanoic acid (pyrene-C12:0), a fluorescent fatty acid analog, as a substrate for fatty acid β-oxidation. When human skin fibroblasts were incubated with pyrene-C12:0, β-oxidation products such as pyrene-C10:0 and pyrene-C8:0 were generated time-dependently. These β-oxidation products were scarcely detected in the fibroblasts from patients with Zellweger syndrome, a peroxisomal biogenesis disorder. In contrast, in fibroblasts with mitochondrial carnitine-acylcarnitine translocase deficiency, the β-oxidation products were detected at a level similar to control fibroblasts. These results indicate that the β-oxidation of pyrene-C12:0 takes place in peroxisomes, but not mitochondria, so pyrene-C12:0 is useful for measuring peroxisomal fatty acid β-oxidation activity. In X-ALD fibroblasts, the β-oxidation activity for pyrene-C12:0 was approximately 40 % of control fibroblasts, which is consistent with previous results using [1-(14)C]lignoceric acid as the substrate. The present study provides a convenient procedure for screening chemical compounds that stimulate the peroxisomal fatty acid β-oxidation in X-ALD fibroblasts.
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Affiliation(s)
- Masashi Morita
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Shun Matsumoto
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Airi Okazaki
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Kaito Tomita
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Shiro Watanabe
- Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Kosuke Kawaguchi
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Daishiro Minato
- Laboratory of Synthetic and Medicinal Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yuji Matsuya
- Laboratory of Synthetic and Medicinal Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Nobuyuki Shimozawa
- Division of Genomic Research, Life Science Research Center, Gifu University, Gifu, 501-1193, Japan
| | - Tsuneo Imanaka
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
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Wang GL, Wang J, Douglas G, Browning M, Hahn S, Ganesh J, Cox S, Aleck K, Schmitt ES, Zhang W, Wong LJC. Expanded molecular features of carnitine acyl-carnitine translocase (CACT) deficiency by comprehensive molecular analysis. Mol Genet Metab 2011; 103:349-57. [PMID: 21605995 DOI: 10.1016/j.ymgme.2011.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/02/2011] [Accepted: 05/02/2011] [Indexed: 11/23/2022]
Abstract
Carnitine-acylcarnitine translocase (CACT) deficiency is a rare autosomal recessive disease of fatty acid oxidation, mainly affecting long chain fatty acid utilization. The disease usually presents at neonatal period with severe hypoketotic hypoglycemia, hyperammonemia, cardiomyopathy and/or arrhythmia, hepatic dysfunction, skeletal muscle weakness, and encephalopathy. Definitive diagnosis of CACT deficiency by molecular analysis of the SLC25A20 gene has recently become clinically available. In contrast to biochemical analysis, sequence analysis is a more rapid and reliable method for diagnosis of CACT deficiency. In this study, we used Sanger sequencing and target array CGH to identify molecular defects in the SLC25A20 gene of patients with clinical features and an acylcarnitine profile consistent with CACT deficiency. Eight novel mutations, including a large 25.9 kb deletion encompassing exons 5 to 9 of SLC25A20 were found. Review of the published cases revealed that CACT deficiency is a pan-ethnic disorder with a broad mutation spectrum. Mutations are distributed along the entire gene without a hot spot. Two thirds of them are nonsense, frame-shift, or splice site mutations resulting in premature stop codons. This study underscores the importance of comprehensive molecular analysis, including sequencing and targeted array CGH of the SLC25A20 gene when CACT deficiency is suspected.
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Affiliation(s)
- Guo-li Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, NAB2015, Houston, TX 77030, USA
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Al-Mendalawi MD. Carnitine-acylcarnitine translocase deficiency. Clinical course of 3 Saudi children with a severe phenotype. Saudi Med J 2011; 32:203; author reply 203. [PMID: 21301774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
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Al-Sannaa NA, Cheriyan GM. Carnitine-acylcarnitine translocase deficiency. Clinical course of three Saudi children with a severe phenotype. Saudi Med J 2010; 31:931-934. [PMID: 20714679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
Carnitine-acylcarnitine translocase (CACT) deficiency (McKusick 212138) is a rare life threatening disorder characterized by hypoketotic hypoglycemia, hyperammonemia, encephalopathy, cardiomyopathy hepatopathy, and myopathy. Here, we present a detailed clinical course of 3 Saudi siblings with a severe phenotype. The third patient was described in more detail. Early medical intervention in the form of 25% dextrose intravenous infusion and carnitine supplement followed by a gradual introduction of a high carbohydrate low fat special formula resulted in a good clinical and biochemical response to the treatment in our patient. However, early nephrocalcinosis, severe hypotonia, and subsequently intravascular cerebral accident could not be prevented. He died at 18 months of age as a result of metabolic decompensation. This suggests that CACT deficiency is still a lethal disorder even with an early and aggressive medical intervention.
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Affiliation(s)
- Nouriya A Al-Sannaa
- Dhahran Health Center, Pediatrics Services Division, Saudi Aramco, Dhahran, Kingdom of Saudi Arabia.
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Morita M, Kanai M, Mizuno S, Iwashima M, Hayashi T, Shimozawa N, Suzuki Y, Imanaka T. Baicalein 5,6,7-trimethyl ether activates peroxisomal but not mitochondrial fatty acid beta-oxidation. J Inherit Metab Dis 2008; 31:442-9. [PMID: 18470630 DOI: 10.1007/s10545-008-0857-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Revised: 02/26/2008] [Accepted: 03/31/2008] [Indexed: 11/28/2022]
Abstract
Recently, we reported that baicalein 5,6,7-trimethyl ether (BTM), a flavonoid, is capable of activating fatty acid beta-oxidation in X-linked adrenoleukodystrophy (X-ALD) fibroblasts (FEBS Lett. 2005; 579: 409-414). The objective of this study was to clarify whether BTM activates peroxisomal and/or mitochondrial fatty acid beta-oxidation. We first analysed the effect of BTM on fatty acid beta-oxidation in fibroblasts derived from healthy controls as well as patients with X-ALD, mitochondrial carnitine-acylcarnitine translocase (CACT) deficiency, and peroxisome biogenesis disorder, Zellweger syndrome. Lignoceric acid (C(24:0)) beta-oxidation in the fibroblasts was stimulated by treatment with BTM, except for Zellweger fibroblasts. In contrasts, palmitic acid (C(16:0)) beta-oxidation was increased (2.8-fold) only in CACT-deficient fibroblasts. In U87 glioblastoma cells, C(24:0) beta-oxidation was also activated by treatment with BTM but C(16:0) beta-oxidation was not. The C(16:0) beta-oxidation was, however, significantly increased in the presence of 2-[5-(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA), a carnitine palmitoyltransferase I inhibitor. These results indicate that BTM activates peroxisomal but not mitochondrial fatty acid beta-oxidation. In addition, we found that BTM did not upregulate the expression of ABCD2/ALDR, ABCD3/PMP70, ACOX1 and FATP4 genes but slightly increased ACSVL1 gene expression.
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Affiliation(s)
- M Morita
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
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Chegary M, Te Brinke H, Doolaard M, Ijlst L, Wijburg FA, Wanders RJA, Houten SM. Characterization of L-aminocarnitine, an inhibitor of fatty acid oxidation. Mol Genet Metab 2008; 93:403-10. [PMID: 18077198 DOI: 10.1016/j.ymgme.2007.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 11/01/2007] [Accepted: 11/01/2007] [Indexed: 11/20/2022]
Abstract
The pathogenesis of hypoketotic hypoglycemia and cardiomyopathy in patients with fatty acid oxidation (FAO) disorders is still poorly understood. In vitro studies are hampered by the lack of natural mutants to asses the effect of FAO inhibition. In addition, only a few inhibitors of FAO are known. Furthermore, most inhibitors of FAO are activating ligands of peroxisome proliferator-activated receptors (PPARs). We show that l-aminocarnitine (L-AC), a carnitine analog, inhibits FAO efficiently, but does not activate PPAR. L-AC inhibits carnitine palmitoyltransferase (CPT) with different sensitivities towards CPT1 and CPT2, as well as carnitine acylcarnitine translocase (CACT). We further characterized L-AC using fibroblasts cell lines from controls and patients with different FAO defects. In these cell lines acylcarnitine profiles were determined in culture medium after loading with [U-(13)C]palmitic acid. In control fibroblasts, L-AC inhibits FAO leading to a reduction of C2-acylcarnitine and elevation of C16-acylcarnitine. In very long-chain acyl-CoA dehydrogenase (VLCAD)-deficient fibroblasts, L-AC decreased the elevated C14-acylcarnitine and increased C16-acylcarnitine. In CACT and CPT2-deficient cell lines, L-AC did not change the already elevated C16-acylcarnitine level, showing that CPT1 is not inhibited. Oxidation of pristanic acid was only partly inhibited at high L-AC concentrations, indicating minimal CACT inhibition. Therefore, we conclude that in intact cells L-AC inhibits CPT2. Combined with our observation that l-AC does not activate PPAR, we suggest that L-AC is useful to simulate a FAO defect in cells from different origin.
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Affiliation(s)
- Malika Chegary
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases (F0-222), Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Pierre G, Macdonald A, Gray G, Hendriksz C, Preece MA, Chakrapani A. Prospective treatment in carnitine-acylcarnitine translocase deficiency. J Inherit Metab Dis 2007; 30:815. [PMID: 17508264 DOI: 10.1007/s10545-007-0518-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 04/05/2007] [Accepted: 04/12/2007] [Indexed: 10/23/2022]
Abstract
Carnitine-acylcarnitine translocase (CACT) deficiency is a rare disorder that results in long-chain fatty acids being unavailable for mitochondrial beta-oxidation and ketogenesis. It can present in the neonatal period or infancy with a severe clinical form, typically with convulsions, hypothermia, encephalopathy, cardiomyopathy and liver dysfunction, or with a milder phenotype with episodes of hypoglycaemia and hyperammonaemia during intercurrent illness. Investigations show hypoketonaemia, intermittent dicarboxyluria and hypocarnitinaemia with grossly elevated acylcarnitines. Enzyme assay or DNA analysis confirms the diagnosis. The severe phenotype results in severe disability or death. The less severe phenotype can also cause significant disability secondary to hypoglycaemia and/or hyperammonaemia at presentation. We report the outcome of two siblings with CACT deficiency. The index patient presented at the age of 2 months during a respiratory illness with hypoglycaemia, hyperammonaemia and cardiorespiratory collapse. Acylcarnitine profiles showed decreased free carnitine but striking elevations of long-chain acylcarnitines. Urine organic acids showed dicarboxylic aciduria. Fatty acid oxidation studies showed reduced oleate and myristate oxidation. His acylcarnitine profile normalized after he was started on a medium-chain triglyceride (MCT) low-fat diet and carnitine supplementation. Low CACT activity on enzyme assay confirmed the diagnosis. He has resulting profound developmental delay and epilepsy. The sibling was prospectively treated with a low-fat MCT diet and carnitine supplementation. Acylcarnitine profile at birth also showed elevated long-chain acylcarnitines. Fatty acid oxidation studies confirmed the diagnosis. To date he has normal development and has not had any significant periods of hypoglycaemia or hyperammonaemia.
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Affiliation(s)
- G Pierre
- Department of Inherited Metabolic Disorders, Birmingham Children's Hospital, Steelhouse Lane, Birmingham, B4 6NH, UK.
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12
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Geven WB, Niezen-Koning KE, Timmer A, van Loon AJ, Wanders RJA, van Spronsen FJ. Pre-eclampsia in a woman whose child suffered from lethal carnitine-acylcarnitine translocase deficiency. BJOG 2007; 114:1028-30. [PMID: 17578469 DOI: 10.1111/j.1471-0528.2007.01411.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- W B Geven
- Department of Pediatrics, Martini Hospital, Groningen, The Netherlands.
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13
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Lee RSY, Lam CW, Lai CK, Yuen YP, Chan KY, Shek CC, Chan AYW, Chow CB. Carnitine-acylcarnitine translocase deficiency in three neonates presenting with rapid deterioration and cardiac arrest. Hong Kong Med J 2007; 13:66-8. [PMID: 17277394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
We report on three Chinese neonates with carnitine-acylcarnitine translocase deficiency. They presented within the first 48 hours of life. Two neonates were found in cardiac arrest; one of them survived after resuscitation. The third neonate suddenly developed cardiorespiratory insufficiency and succumbed eventually. The clustering of three cases in 5 years suggests that carnitine-acylcarnitine translocase deficiency is not rare in our Chinese population. We advocate that investigation for metabolic diseases including carnitine-acylcarnitine translocase deficiency should be performed in cases of sudden infant death and unexplained abrupt clinical deterioration in the early neonatal period. Non-ketotic hypoglycaemia is an early clue. The mainstay of initial treatment is glucose infusion at a rate greater than 7 mg/kg/minute, which inhibits beta-oxidation of fatty acids (the defective enzymatic steps in carnitine-acylcarnitine translocase deficiency) and thus prevents the accumulation of toxic long-chain acylcarnitines.
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Affiliation(s)
- Robert S Y Lee
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong.
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14
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Lamhonwah AM, Tein I. Novel localization of OCTN1, an organic cation/carnitine transporter, to mammalian mitochondria. Biochem Biophys Res Commun 2006; 345:1315-25. [PMID: 16729965 DOI: 10.1016/j.bbrc.2006.05.026] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2006] [Accepted: 05/01/2006] [Indexed: 12/22/2022]
Abstract
Carnitine is a zwitterion essential for the beta-oxidation of fatty acids. We report novel localization of the organic cation/carnitine transporter, OCTN1, to mitochondria. We made GFP- and RFP-human OCTN1 cDNA constructs and showed expression of hOCTN1 in several transfected mammalian cell lines. Immunostaining of GFP-hOCTN1 transfected cells with different intracellular markers and confocal fluorescent microscopy demonstrated mitochondrial expression of OCTN1. There was striking co-localization of an RFP-hOCTN1 fusion protein and a mitochondrial-GFP marker construct in transfected MEF-3T3 and no co-localization of GFP-hOCTN1 in transfected human skin fibroblasts with other intracellular markers. L-[(3)H]Carnitine uptake in freshly isolated mitochondria of GFP-hOCTN1 transfected HepG2 demonstrated a K(m) of 422 microM and Western blot with an anti-GFP antibody identified the expected GFP-hOCTN1 fusion protein (90 kDa). We showed endogenous expression of native OCTN1 in HepG2 mitochondria with anti-GST-hOCTN1 antibody. Further, we definitively confirmed intact L-[(3)H]carnitine uptake (K(m) 1324 microM), solely attributable to OCTN1, in isolated mitochondria of mutant human skin fibroblasts having <1% of carnitine acylcarnitine translocase activity (alternate mitochondrial carnitine transporter). This mitochondrial localization was confirmed by TEM of murine heart incubated with highly specific rabbit anti-GST-hOCTN1 antibody and immunogold labeled goat anti-rabbit antibody. This suggests an important yet different role for OCTN1 from other OCTN family members in intracellular carnitine homeostasis.
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Affiliation(s)
- Anne-Marie Lamhonwah
- Division of Neurology, Department of Pediatrics, University of Toronto, Ont., Canada
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15
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Abstract
The carnitine-acylcarnitine translocase (CACT) is one of the components of the carnitine cycle. The carnitine cycle is necessary to shuttle long-chain fatty acids from the cytosol into the intramitochondrial space where mitochondrial beta-oxidation of fatty acids takes place. The oxidation of fatty acids yields acetyl-coenzyme A (CoA) units, which may either be degraded to CO(2) and H(2)O in the citric acid cycle to produce ATP or converted into ketone bodies which occurs in liver and kidneys. Metabolic consequences of a defective CACT are hypoketotic hypoglycaemia under fasting conditions, hyperammonemia, elevated creatine kinase and transaminases, dicarboxylic aciduria, very low free carnitine and an abnormal acylcarnitine profile with marked elevation of the long-chain acylcarnitines. Clinical signs and symptoms in CACT deficient patients, are a combination of energy depletion and endogenous toxicity. The predominantly affected organs are brain, heart and skeletal muscle, and liver, leading to neurological abnormalities, cardiomyopathy and arrythmias, skeletal muscle damage and liver dysfunction. Most patients become symptomatic in the neonatal period with a rapidly progressive deterioration and a high mortality rate. However, presentations at a later age with a milder phenotype have also been reported. The therapeutic approach is the same as in other long-chain fatty acid disorders and includes intravenous glucose (+/- insulin) administration to maximally inhibit lipolysis and subsequent fatty acid oxidation during the acute deterioration, along with other measures such as ammonia detoxification, depending on the clinical features. Long-term strategy consists of avoidance of fasting with frequent meals and a special diet with restriction of long-chain fatty acids. Due to the extremely low free carnitine concentrations, carnitine supplementation is often needed. Acylcarnitine profiling in plasma is the assay of choice for the diagnosis at a metabolite level. However, since the acylcarnitine profile observed in CACT-deficient patients is identical to that in CPT2-deficient patients, definitive identification of CACT-deficiency in a certain patient requires determination of the activity of CACT. Subsequently, mutational analysis of the CACT gene can be performed. So far, 9 different mutations have been identified in the CACT gene.
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Affiliation(s)
- M E Rubio-Gozalbo
- Department of Pediatrics, University Hospital Maastricht, Maastricht, The Netherlands.
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16
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Iacobazzi V, Invernizzi F, Baratta S, Pons R, Chung W, Garavaglia B, Dionisi-Vici C, Ribes A, Parini R, Huertas MD, Roldan S, Lauria G, Palmieri F, Taroni F. Molecular and functional analysis of SLC25A20 mutations causing carnitine-acylcarnitine translocase deficiency. Hum Mutat 2005; 24:312-20. [PMID: 15365988 DOI: 10.1002/humu.20085] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The enzyme carnitine-acylcarnitine translocase (CACT) is involved in the transport of long-chain fatty acids into mitochondria. CACT deficiency is a life-threatening, recessively inherited disorder of lipid beta-oxidation which manifests in early infancy with hypoketotic hypoglycemia, cardiomyopathy, liver failure, and muscle weakness. We report here the clinical, biochemical, and molecular features of six CACT-deficient patients from Italy, Spain, and North America who exhibited significant clinical heterogeneity. In five patients (Patients 1, 2, 4, 5, and 6) the disease manifested in the neonatal period, while the remaining patient (Patient 3), the younger sibling of an infant who had died with clinical suspicion of fatty acid oxidation defect, has been treated since birth and was clinically asymptomatic at 4.5 years of age. Patients 1 and 4 were deceased within 6 months from the onset of this study, while the remaining four are still alive at 8, 4.5, 3.5, and 2 years, respectively. Sequence analysis of the CACT gene (SLC25A20) disclosed five novel mutations and three previously reported mutations. Three patients were homozygous for the identified mutations. Two of the novel mutations (c.718+1G>C and c.843+4_843+50del) altered the donor splice site of introns 7 and 8, respectively. The 47-nt deletion in intron 8 caused both skipping of exon 8 only and skipping of exons 6-8. Four mutations [[c.159dupT;c.163delA] ([p.Gly54Trp;p.Thr55Ala]) c.397C>T (p.Arg133Trp), c.691G>C (p.Asp231His), and c.842C>T (p.Ala281Val)] resulted in amino acid substitutions affecting evolutionarily conserved regions of the protein. Interestingly, one of these exonic mutations (p.Ala281Val) was associated with a splicing defect also characterized by skipping of exons 6-8. The deleterious effect of the p.Arg133Trp substitution was demonstrated by measuring CACT activity upon expression of the normal and the mutant protein in E. coli and functional reconstitution into liposomes. Combined analysis of clinical, biochemical, and molecular data failed to indicate a correlation between the phenotype and the genotype.
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Affiliation(s)
- Vito Iacobazzi
- Laboratory of Biochemistry and Molecular Biology, Department of Pharmaco-Biology, University of Bari, Bari, Italy
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17
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Iacobazzi V, Pasquali M, Singh R, Matern D, Rinaldo P, Amat di San Filippo C, Palmieri F, Longo N. Response to therapy in carnitine/acylcarnitine translocase (CACT) deficiency due to a novel missense mutation. Am J Med Genet A 2004; 126A:150-5. [PMID: 15057979 DOI: 10.1002/ajmg.a.20573] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Deficiency of carnitine/acylcarnitine translocase (CACT) is an autosomal recessive disorder of the carnitine cycle resulting in the inability to transfer fatty acids across the inner mitochondrial membrane. Only a limited number of affected patients have been reported and the effect of therapy on this condition is still not well defined. Here, we report a new patient with this disorder and follow the response to therapy. Our patient was the product of a consanguineous marriage. He presented shortly after birth with cardiac myopathy and arrhythmia coupled with severe non-ketotic hypoglycemia. Initial metabolic studies indicated severe non-ketotic C6-C10 dicarboxylic aciduria, plasma carnitine deficiency, and a characteristic elevation of plasma C:16:0, C18:1, and C18:2 acylcarnitine species. Enzyme assay confirmed deficiency of CACT activity. Molecular studies indicated that this child was homozygous, and both parents heterozygous, for a single bp change converting glutamine 238 to arginine (Q238R). Therapy with a formula providing most of the fat via medium chain triglycerides (MCT) and carnitine supplementation reduced the concentration of long-chain acylcarnitines and reversed cardiac symptoms and the hypoglycemia. These results suggest that carnitine and MCT may be effective in treating this defect of long-chain fatty acid oxidation.
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Affiliation(s)
- Vito Iacobazzi
- Dipartimento Farmaco-Biologico, University of Bari, Italy
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18
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Galron D, Birk OS, Kazanovitz A, Moses SW, Hershkovitz E. Carnitine-acylcarnitine translocase deficiency: identification of a novel molecular defect in a Bedouin patient. J Inherit Metab Dis 2004; 27:267-73. [PMID: 15159657 DOI: 10.1023/b:boli.0000028780.01670.61] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Carnitine-acylcarnitine translocase CACT deficiency is a very rare autosomal recessive disease. The neonatal phenotype of CACT deficiency is characterized by hypoketotic hypoglycaemia, hyperammonaemia, cardiomyopathy and skeletal muscle weakness culminating in early death. The disease is caused by mutations in the CACT gene, which encodes a protein transporting long-chain fatty acid carnitine esters into the mitochondrial matrix. In this report, we describe the first case of CACT deficiency in the Bedouin population in Israel. The patient, the first son of consanguineous parents, was born at term after uneventful delivery. During the second day of life, he developed clinical signs of an acute metabolic crisis with severe hypoglycaemia and hyperammonaemia. Biochemical investigation suggested the diagnosis of CACT deficiency. Genetic molecular analysis confirmed this diagnosis by demonstrating that the affected child was homozygous for a novel missense mutation 793A>G, substituting glutamine by arginine (Q238R) in exon 7 of the CACT gene. Despite medical treatment and adequate nutrition, the patient died at 6 months of age.
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Affiliation(s)
- D Galron
- Genetic Institute, Soroka University Medical Center, Beer-Sheva, Israel
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19
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Al Aqeel AI, Rashid MS, Ruiter JP, Ijlst L, Wanders RJ. A novel molecular defect of the carnitine acylcarnitine translocase gene in a Saudi patient. Clin Genet 2003; 64:163-5. [PMID: 12859414 DOI: 10.1034/j.1399-0004.2003.00117.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Lam CW, Lai CK, Chow CB, Tong SF, Yuen YP, Mak YF, Chan YW. Ethnic-specific splicing mutation of the carnitine-acylcarnitine translocase gene in a Chinese neonate presenting with sudden unexpected death. Chin Med J (Engl) 2003; 116:1110-2. [PMID: 12890396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Affiliation(s)
- Ching-Wan Lam
- Department of Chemical Pathology, the Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
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21
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Rubio-Gozalbo ME, Vos P, Forget PP, Van Der Meer SB, Wanders RJA, Waterham HR, Bakker JA. Carnitine-acylcarnitine translocase deficiency: case report and review of the literature. Acta Paediatr 2003; 92:501-4. [PMID: 12801121 DOI: 10.1111/j.1651-2227.2003.tb00586.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM Carnitine-acylcarnitine translocase (CACT) deficiency is an inborn error of metabolism involving the mitochondrial beta-oxidation of long-chain fatty acids. The aim of this study was to report on a new case (neonatal phenotype) and review the literature data on 24 previously reported cases. METHODS Clinical data of the new case are described and compared with the previous reports. RESULTS The patient with a novel mutation had clinical features and biochemical findings similar to those of the other reported patients. CONCLUSION CACT is an entity in which clinical encephalopathy, hepatomegaly and arrythmias are common. Hyperammonaemia and elevation of creatine kinase seem to be constant findings as in other disorders of mitochondrial beta-oxidation of long-chain fatty acids. The mortality rate is very high.
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Affiliation(s)
- M E Rubio-Gozalbo
- Departments of Pediatrics, University Hospital Maastricht, The Netherlands.
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22
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Costa C, Costa JM, Slama A, Boutron A, Vequaud C, Legrand A, Brivet M. Mutational spectrum and DNA-based prenatal diagnosis in carnitine-acylcarnitine translocase deficiency. Mol Genet Metab 2003; 78:68-73. [PMID: 12559850 DOI: 10.1016/s1096-7192(02)00205-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Carnitine-acylcarnitine translocase (CAC) deficiency is a rare autosomal recessive disorder of long-chain fatty acid oxidation with a severe outcome. We report mutation analysis in a cohort of 12 patients. Twelve mutations were identified of which 9 have not been reported so far (G28C, D32N, R178Q, P230R, D231H, 179delG, 802delG, 69-70insTGTGC, and 609-1g>a). Altogether, including our results, 22 mutations of the CAC gene have been published to date in 23 patients demonstrating the allelic heterogeneity of CAC deficiency. DNA-based prenatal diagnosis was performed for the first time in pregnancies at risk for CAC deficiency. Two fetuses were affected and one pregnancy was terminated by family decision. Two other fetuses had normal genotype and five others were heterozygotes. All the offspring of these seven pregnancies are alive and apparently healthy.
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Affiliation(s)
- C Costa
- Laboratoire de biochimie, AP-HP hôpital H Mondor, France
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23
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Kimura M, Yamaguchi S. [Carnitine acylcarnitine translocase deficiency]. Nihon Rinsho 2002; 60 Suppl 4:714-6. [PMID: 12013981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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24
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Kimura M, Yamaguchi S. [Mitochondrial carnitine acylcarnitine translocase]. Nihon Rinsho 2002; 60 Suppl 4:85-7. [PMID: 12014004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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25
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Yorifuji S. [Carnitine acylcarnitine translocase deficiency]. Ryoikibetsu Shokogun Shirizu 2002:57-9. [PMID: 11596450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- S Yorifuji
- Department of Laboratory Science, School of Allied Health Sciences, Faculty of Medicine, Osaka University
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26
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Ferdinandusse S, Denis S, Mooijer PA, Zhang Z, Reddy JK, Spector AA, Wanders RJ. Identification of the peroxisomal beta-oxidation enzymes involved in the biosynthesis of docosahexaenoic acid. J Lipid Res 2001; 42:1987-95. [PMID: 11734571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
DHA (C22:6n-3) is an important PUFA implicated in a number of (patho)physiological processes. For a long time, the exact mechanism of DHA formation has remained unclear, but now it is known that it involves the production of tetracosahexaenoic acid (C24:6n-3) from dietary linolenic acid (C18:3n-3) via a series of elongation and desaturation reactions, followed by beta-oxidation of C24:6n-3 to C22:6n-3. Although DHA is deficient in patients lacking peroxisomes, the intracellular site of retroconversion of C24:6n-3 has remained controversial. By making use of fibroblasts from patients with defined mitochondrial and peroxisomal fatty acid oxidation defects, we show in this article that peroxisomes, and not mitochondria, are involved in DHA formation by catalyzing the beta-oxidation of C24:6n-3 to C22:6n-3. Additional studies of fibroblasts from patients with X-linked adrenoleukodystrophy, straight-chain acyl-CoA oxidase (SCOX) deficiency, d-bifunctional protein (DBP) deficiency, and rhizomelic chondrodysplasia punctata type 1, and of fibroblasts from l-bifunctional protein and sterol carrier protein X (SCPx) knockout mice, show that the main enzymes involved in beta-oxidation of C24:6n-3 to C22:6n-3 are SCOX, DBP, and both 3-ketoacyl-CoA thiolase and SCPx. These findings are of importance for the treatment of patients with a defect in peroxisomal beta-oxidation.
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Affiliation(s)
- S Ferdinandusse
- Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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27
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Hsu BY, Iacobazzi V, Wang Z, Harvie H, Chalmers RA, Saudubray JM, Palmieri F, Ganguly A, Stanley CA. Aberrant mRNA splicing associated with coding region mutations in children with carnitine-acylcarnitine translocase deficiency. Mol Genet Metab 2001; 74:248-55. [PMID: 11592821 DOI: 10.1006/mgme.2001.3235] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This report describes three infants with genetic defects of carnitine-acylcarnitine translocase (CACT), an inner mitochondrial membrane carrier that is essential for long-chain fatty acid oxidation. Two of the patients were of European and Chinese origin; the third was from consanguineous Turkish parents. CACT activity was totally deficient in cultured skin fibroblasts from all three patients. Patient 1 was heterozygous for a paternal frameshift mutation (120 del T in exon 1) and a maternal lariat branch point mutation (-10 T --> G in intron 2). Patient 2 was heterozygous for the same lariat branch point (-10T --> G intron 2) mutation, derived from the father, and a maternal frameshift mutation (362 del G in exon 3). Patient 3 was homozygous for a frameshift mutation (306 del C in exon 3). All of the three frameshift mutations give rise to the same stop codon at amino acid residue 127 which is predicted to cause premature protein truncation. In addition, cDNA transcript analysis showed that these coding sequence mutations also increase the amount of aberrant mRNA splicing and exon skipping at distances up to 7.7 kb nucleotides from mutation sites. The data suggest that the stability of mRNA transcripts is decreased or the frequency of aberrant splicing is increased in the presence of CACT coding sequence mutations. These results confirm that CACT is the genetic locus of the recessive mutations responsible for the fatal defects of fatty acid metabolism previously associated with deficiency of translocase activity in these three cases.
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Affiliation(s)
- B Y Hsu
- Division of Endocrinology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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28
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Wasant P, Naylor EW, Liammongkolkul S. Detection of inherited metabolic disorders via tandem mass spectrometry in Thai infants. Southeast Asian J Trop Med Public Health 2001; 30 Suppl 2:154-9. [PMID: 11400758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
From a retrospective study in Medical Genetics Unit, Department of Pediatrics, Siriraj Hospital Faculty of Medicine, Mahidol University in Bangkok (1983-1988), the estimated pediatric patients with clinically suspected IEM are approximately 2-4% of total annual pediatrics admission of 5,000 or more. This is, a low estimation since survey from all teaching hospitals in the country including the largest Children's Hospital in Bangkok indicated the presence of numerous IEM. However, most IEM were clinically diagnosed with limited laboratory facilities. We started a collaboration with Magee Womens Hospital of Pittsburgh and NeoGen Screening, USA; using tandem mass spectrometry to diagnose high risk infants and children for IEM from July 1993 to March 1998. Of total 146 samples sent, we detected numerous metabolic disorders (11.2%) eg phenylketonuria, organic acidemia, maple syrup urine disease, isovaleric acidemia, methylmalonic acidemia, albinism, translocase/carnitine palmitoyltransferase type II, G6PD deficiency and lysinuric protein intolerance.
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Affiliation(s)
- P Wasant
- Department of Pediatrics, Siriraj Hospital Faculty of Medicine Mahidol University, Bangkok, Thailand
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29
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Yang BZ, Mallory JM, Roe DS, Brivet M, Strobel GD, Jones KM, Ding JH, Roe CR. Carnitine/acylcarnitine translocase deficiency (neonatal phenotype): successful prenatal and postmortem diagnosis associated with a novel mutation in a single family. Mol Genet Metab 2001; 73:64-70. [PMID: 11350184 DOI: 10.1006/mgme.2001.3162] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neonatal phenotype of carnitine-acylcarnitine translocase (CACT) deficiency is one of the most severe and usually lethal mitochondrial fat oxidation disorders characterized by hypoketotic hypoglycemia, hyperammonemia, cardiac abnormalities, and early death. In this study, the proband was the daughter of consanguineous Hispanic parents. At 36 h of life, she had bradycardia and died at 4 days of age without a specific diagnosis. In a subsequent pregnancy, prenatal counseling and amniocentesis were provided. Incubation of the amniocytes from this pregnancy and fibroblasts (from the dead proband) with [16-(2)H(3)]palmitic acid and analysis by tandem mass spectrometry revealed an increasedconcentration of [16-(2)H(3)]palmitoylcarnitine, suggesting the diagnoses of either CACT or carnitine palmitoyltransferase II (CPT-II) deficiency. CACT enzyme activity was absent in both cell lines. Molecular investigation of cDNA from the dead proband and her affected sibling revealed aberrant CACT cDNA species, including exon 3 skipping, both exon 3 and 4 skipping, and a 13-bp insertion at cDNA position 388. Investigation of these cell lines for mutations affecting CACT RNA processing by analysis of CACT gene sequences, including intron and exon boundaries, revealed a single nucleotide G deletion at the donor site in intron 3 which resulted in exon skipping and a 13-bp insertion. The proband and her affected sibling were homozygous for this deletion.
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Affiliation(s)
- B Z Yang
- Kimberly H. Courtwright and Joseph W. Summers Institute of Metabolic Disease, Baylor University Medical Center, 3812 Elm Street, Dallas, TX 7522, USA.
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30
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Lopriore E, Gemke RJ, Verhoeven NM, Jakobs C, Wanders RJ, Roeleveld-Versteeg AB, Poll-The BT. Carnitine-acylcarnitine translocase deficiency: phenotype, residual enzyme activity and outcome. Eur J Pediatr 2001; 160:101-4. [PMID: 11271379 DOI: 10.1007/s004310000644] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED Carnitine-acylcarnitine translocase deficiency is a rare and life-threatening mitochondrial fatty acid beta-oxidation disorder. We describe a patient who, despite a severe clinical course and an extremely low carnitine-acylcarnitine translocase activity, is currently alive and in good health. We performed an extensive analysis of all previously published cases in order to evaluate the clinical features and prognostic factors. Reports on 21 patients with carnitine-acylcarnitine translocase deficiency were obtained. Only 5 out of the 21 patients survived early childhood. At least 20 siblings are reported to have died of sudden unexplained death in the neonatal period. Although phenotype and residual enzyme activity have been suggested to be related to outcome, we were not able to establish such a relationship. CONCLUSION Phenotype and residual enzyme activity do not appear to be major prognostic factors. Vigorous work-up in order to reach an expedite diagnosis and prompt medical intervention during acute episodes, especially in the neonatal period, may prevent fatal complications.
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Affiliation(s)
- E Lopriore
- Department of Paediatrics, Academic Hospital Free University, Amsterdam, The Netherlands.
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31
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IJlst L, van Roermund CW, Iacobazzi V, Oostheim W, Ruiter JP, Williams JC, Palmieri F, Wanders RJ. Functional analysis of mutant human carnitine acylcarnitine translocases in yeast. Biochem Biophys Res Commun 2001; 280:700-6. [PMID: 11162577 DOI: 10.1006/bbrc.2000.4178] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long chain fatty acids are translocated as carnitine esters across the mitochondrial inner membrane by carnitine acylcarnitine translocase (CACT). We report functional studies on the mutant CACT proteins from a severe and a mild patient with CACT deficiency. CACT activities in fibroblasts of both patients were markedly deficient with some residual activity (<1%) in the milder patient. Palmitate oxidation activity in cells from the severe patient was less than 5% but in the milder patient approximately 27% residual activity was found. Sequencing of the CACT cDNAs revealed a c.241G>A (G81R) in the severe and a c.955insC mutation (C-terminal extension of 21 amino acids (CACT(+21aa)) in the milder patient. The effect of both mutations on the protein was studied in a sensitive expression system based on the ability of human CACT to functionally complement a CACT-deletion strain of yeast. Expression in this strain revealed significant residual activity for CACT(+21aa), while the CACT(G81R) was inactive.
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Affiliation(s)
- L IJlst
- Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, 1100 DE Amsterdam, The Netherlands
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32
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Röschinger W, Muntau AC, Duran M, Dorland L, IJlst L, Wanders RJ, Roscher AA. Carnitine-acylcarnitine translocase deficiency: metabolic consequences of an impaired mitochondrial carnitine cycle. Clin Chim Acta 2000; 298:55-68. [PMID: 10876004 DOI: 10.1016/s0009-8981(00)00268-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We describe a patient with carnitine-acylcarnitine translocase deficiency (MIM 212138), who presented with neonatal generalized seizures, heart failure, and coma. Laboratory evaluation revealed hypoglycemia, hyperammonemia, lactic acidemia, hyperuricemia, and mild dicarboxylic aciduria. The fact that total plasma carnitine (7.1 micromol/l [20-30]) and free carnitine (1.9 micromol/l [12-18]) were low together with a high acylcarnitine/free carnitine ratio of 2.7 [0.4-1.0] prompted acylcarnitine analysis. This revealed the presence of large amounts of long-chain derivatives including C(16:0), C(16:1), C(18:1), C(18:2). Based on these findings carnitine-acylcarnitine translocase deficiency was suspected which was confirmed by enzyme studies in fibroblasts. The underlying complex metabolic consequences of this defect are reviewed. Prenatal diagnosis was performed in a subsequent pregnancy and a defect ruled out by measurement of carnitine-acylcarnitine translocase activity in cultured chorionic villi cells. As the clinical recognition of a life-threatening fatty acid oxidation disorder may be difficult, defects in this pathway should be considered in any child with coma, an episode of a Reye-like syndrome, and cardiomyopathy. Since routine laboratory tests often do not provide clues about potential disorders and profiles of urinary organic acids may not be characteristic, we recommend to measure free carnitine and acylcarnitines in plasma in any child with hyperammonemia, hypo/hyperketotic hypoglycemia or lactic acidemia for prompt treatment, proper genetic counseling, and potential prenatal diagnosis.
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Affiliation(s)
- W Röschinger
- Department of Pediatrics, Ludwig-Maximilians-University Munich, D-80337, Munich, Germany.
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33
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Ogawa A, Yamamoto S, Kanazawa M, Takayanagi M, Hasegawa S, Kohno Y. Identification of two novel mutations of the carnitine/acylcarnitine translocase (CACT) gene in a patient with CACT deficiency. J Hum Genet 2000; 45:52-5. [PMID: 10697964 DOI: 10.1007/s100380050010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Carnitine/acylcarnitine translocase (CACT) transports acylcarnitines into mitochondria in exchange for free carnitine, and is therefore an essential component within the fatty acid beta-oxidation pathway. CACT deficiency is an autosomal recessive disease caused by a mutation of the CACT gene. We have identified two novel mutations of the CACT gene in a patient with CACT deficiency. The first, a deletion mutation (146 del T), leads to premature termination and results in a very immature CACT protein. The second, a splicing mutation (261-10T > G), results in either skipping of exons 3 and 4, or of exon 3 alone, and leads to truncation of the protein. Each of these mutations is hypothesized to destroy the function of the CACT protein. We propose that each of these mutations of the CACT gene play a causative role in the disease.
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Affiliation(s)
- A Ogawa
- Department of Pediatrics, Chiba University School of Medicine, Japan.
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34
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Roe DS, Roe CR, Brivet M, Sweetman L. Evidence for a short-chain carnitine-acylcarnitine translocase in mitochondria specifically related to the metabolism of branched-chain amino acids. Mol Genet Metab 2000; 69:69-75. [PMID: 10655160 DOI: 10.1006/mgme.1999.2950] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carnitine-acylcarnitine translocase (CATR) deficiency is a severe defect in fatty acid oxidation which presents early in life most frequently with hypoglycemia, hyperammonemia, and severe cardiac abnormalities. CATR exchanges acylcarnitines of various chain lengths for free carnitine across the mitochondrial membrane. In vitro studies in intact fibroblasts from patients with documented deficiency of CATR were probed with stable-isotope-labeled precursors and the resulting acylcarnitines were analyzed by tandem mass spectrometry. After a 72-h incubation with l-[(2)H(3)]carnitine the translocase-deficient cells produced acylcarnitines in which the deuterium was incorporated into short-chain acylcarnitines, C2-C5. Experiments with simultaneous incubation of l-[(2)H(3)]carnitine and l-[(13)C(6)]isoleucine produced [(13)C(5)]2-methylbutyryl-[(2)H(3)]carnitine and [(13)C(3)]propionyl-[(2)H(3)]carnitine indicating exchange of labeled acylcarnitine from inside the mitochondrial matrix with labeled free carnitine. These studies support the possible existence of a "branched-chain" carnitine-acylcarnitine translocator in mitochondria.
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Affiliation(s)
- D S Roe
- Kimberly H. Courtwright & Joseph W. Summers, Institute of Metabolic Disease, Dallas, Texas, 75226, USA
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35
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Nuoffer JM, de Lonlay P, Costa C, Roe CR, Chamoles N, Brivet M, Saudubray JM. Familial neonatal SIDS revealing carnitine-acylcarnitine translocase deficiency. Eur J Pediatr 2000; 159:82-5. [PMID: 10653336 DOI: 10.1007/pl00013810] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED A patient with a severe phenotype of carnitine-acylcarnitine translocase deficiency (CATR)(McKusick 212138) is reported. Prior to birth, a defect in beta-oxidation was suspected because of neonatal death of six siblings. Dietary treatment during neonatal adaptation and the subsequent six months of life and a trial of carnitine supplementation are reported. The rapidity with which long chain fatty acid metabolites can accumulate and induce secondary carnitine deficiency within a few hours after birth in an infant with CATR is noteworthy. CONCLUSION High rates of glucose suppressed neonatal lipolysis in this infant, but did not seem sufficient to avoid secondary carnitine deficiency as in severe forms of CATR. Therefore simultaneous use of insulin and glucose may be necessary to control neonatal lipolysis. Carnitine supplementation and the possible adverse effects of MCT systematically administrated, should be further assessed in patients with CATR.
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Affiliation(s)
- J M Nuoffer
- Department of Metabolic Disease, Hôpital Necker-Enfants, Malades, Paris, France
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36
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Bonnet D, Martin D, Villain E, Jouvet P, Rabier D, Brivet M, Saudubray JM. Arrhythmias and conduction defects as presenting symptoms of fatty acid oxidation disorders in children. Circulation 1999; 100:2248-53. [PMID: 10577999 DOI: 10.1161/01.cir.100.22.2248] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND The clinical manifestations of inherited disorders of fatty acid oxidation vary according to the enzymatic defect. They may present as isolated cardiomyopathy, sudden death, progressive skeletal myopathy, or hepatic failure. Arrhythmia is an unusual presenting symptom of fatty acid oxidation deficiencies. METHODS AND RESULTS Over a period of 25 years, 107 patients were diagnosed with an inherited fatty acid oxidation disorder. Arrhythmia was the predominant presenting symptom in 24 cases. These 24 cases included 15 ventricular tachycardias, 4 atrial tachycardias, 4 sinus node dysfunctions with episodes of atrial tachycardia, 6 atrioventricular blocks, and 4 left bundle-branch blocks in newborn infants. Conduction disorders and atrial tachycardias were observed in patients with defects of long-chain fatty acid transport across the inner mitochondrial membrane (carnitine palmitoyl transferase type II deficiency and carnitine acylcarnitine translocase deficiency) and in patients with trifunctional protein deficiency. Ventricular tachycardias were observed in patients with any type of fatty acid oxidation deficiency. Arrhythmias were absent in patients with primary carnitine carrier, carnitine palmitoyl transferase I, and medium chain acyl coenzyme A dehydrogenase deficiencies. CONCLUSIONS The accumulation of arrhythmogenic intermediary metabolites of fatty acids, such as long-chain acylcarnitines, may be responsible for arrhythmias. Inborn errors of fatty acid oxidation should be considered in unexplained sudden death or near-miss in infants and in infants with conduction defects or ventricular tachycardia. Diagnosis can be easily ascertained by an acylcarnitine profile from blood spots on filter paper.
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Affiliation(s)
- D Bonnet
- Service de Cardiologie Pédiatrique, Hôpital Necker-Enfants Malades, Paris, France.
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37
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Parini R, Invernizzi F, Menni F, Garavaglia B, Melotti D, Rimoldi M, Salera S, Tosetto C, Taroni F. Medium-chain triglyceride loading test in carnitine-acylcarnitine translocase deficiency: insights on treatment. J Inherit Metab Dis 1999; 22:733-9. [PMID: 10472533 DOI: 10.1023/a:1005548201355] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The results of a medium-chain triglyceride loading test in a patient with severe carnitine-acylcarnitine translocase deficiency clearly demonstrated impaired in vivo utilization of medium-chain triglycerides. The loading test was performed at the ages of 7 and 36 months. The diet was adjusted accordingly. The clinical course has been favourable and the child is now in very good condition at age 4 years. We conclude that the utilization of medium-chain triglycerides is only partial in carnitine-acylcarnitine translocase deficiency and cannot reasonably be considered an optimal source of energy for these patients. Careful adjustment of dietetic treatment may help to improve prognosis.
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Affiliation(s)
- R Parini
- Laboratorio Analisi Cliniche, Istituti Clinici di Perfezionamento, Milan, Italy.
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38
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Abstract
Carnitine-acylcarnitine translocase deficiency, like other defects of mitochondrial fatty acid oxidation, is an autosomal, recessively inherited disorder. When the deficiency is near total, it is usually fatal, affects life soon after birth, and constitutes one of the causes of skeletal muscle myopathy, cardiac and liver abnormalities, and childhood sudden death. The presenting features have included neonatal distress, convulsions, hypoglycemia, hyperammonemia, hypoketonemia, intermittent dicarboxyluria, hypothermia, apnea, neurological deterioration, and hypocarnitinemia with grossly elevated acylcarnitines. Two cases of partial translocase deficiency (4-6% residual activity) with milder symptoms and without cardiac involvement have also been identified. Evidence so far indicates that the translocase protein is the product of a single gene. In two cases of translocase deficiency, the accompanying mutations have been identified. The benefits of prenatal diagnosis have been provided to the affected families by assays of the translocase and/or fatty acid oxidation in cultured amniotic/villous cells. In one such case genetic counseling was made possible even when the only specimen available from a deceased sibling was the Guthrie card.
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Affiliation(s)
- S V Pande
- Laboratory of Intermediary Metabolism, Clinical Research Institute of Montreal, Quebec, Canada.
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39
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Affiliation(s)
- A I al Aqeel
- Department of Paediatrics, Riyadh Armed Forces Hospital, Kingdom of Saudi Arabia
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40
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Iacobazzi V, Naglieri MA, Stanley CA, Wanders RJ, Palmieri F. The structure and organization of the human carnitine/acylcarnitine translocase (CACT1) gene2. Biochem Biophys Res Commun 1998; 252:770-4. [PMID: 9837782 DOI: 10.1006/bbrc.1998.9738] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The carnitine/acylcarnitine translocase (CACT) transports acylcarnitines into mitochondria in exchange for free carnitine and it is, therefore, essential for the fatty acid beta-oxidation pathway. We have determined the exon-intron structure of the human CACT gene, which is responsible for a genetic disorder of fatty acid oxidation called CACT deficiency. The gene spans about 16.5 kb and consists of nine exons with the translation start site in exon 1. All the splice acceptor and donor sites conform to the AG/GT rules. All the introns except one are located at the level of the sequences coding for the extramembranous loops of CACT. We have designed a series of intronic oligonucleotide primers for amplifying each of the CACT exons together with their flanking intronic sequences, in segments well suited to detect mutations that would affect splicing of mRNA as well as the coding sequence itself.
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Affiliation(s)
- V Iacobazzi
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Italy
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41
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Yorifuji S. [Carnitine/acylcarnitine translocase deficiency]. Ryoikibetsu Shokogun Shirizu 1998:403-4. [PMID: 9590083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- S Yorifuji
- Department of Laboratory Science, School of Allied Health Sciences, Faculty of Medicine, Osaka University
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42
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Yorifuji S. [Carnitine transporter defect]. Ryoikibetsu Shokogun Shirizu 1998:398-400. [PMID: 9590081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- S Yorifuji
- Department of Laboratory Science, School of Allied Health Sciences, Faculty of Medicine, Osaka University
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43
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Abstract
Carnitine-acylcarnitine translocase deficiency, a rare beta-oxidation defect, is manifest in most cases by cardiomyopathy and death in early childhood. We report an affected patient, 3 years of age, who has had no serious complications. The residual enzyme activity in fibroblasts was higher than in previously reported patients, which may explain the benign clinical course.
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Affiliation(s)
- A A Morris
- Institute of Child Health, London, United Kingdom
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44
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45
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Verhoeven NM, Roe DS, Kok RM, Wanders RJ, Jakobs C, Roe CR. Phytanic acid and pristanic acid are oxidized by sequential peroxisomal and mitochondrial reactions in cultured fibroblasts. J Lipid Res 1998; 39:66-74. [PMID: 9469587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The relationship between peroxisomal and mitochondrial oxidation of the methyl branched fatty acids, phytanic acid and pristanic acid, was studied in normal and mutant human skin fibroblasts with established enzyme deficiencies. Tandem mass spectrometry was used for analysis of the acylcarnitine intermediates. In normal cells, 4,8-dimethylnonanoylcarnitine (C11:0) and 2,6-dimethylheptanoylcarnitine (C9:0) accumulated after incubation with either phytanic acid or pristanic acid. These intermediates were not observed when peroxisome-deficient cells from Zellweger patients were incubated with the same compounds, pointing to the involvement of peroxisomes in the formation of these acylcarnitine intermediates. Similar experiments with fibroblasts deficient in carnitine palmitoyltransferase I, carnitine-acylcarnitine translocase or carnitine palmitoyltransferase II revealed that mitochondrial carnitine palmitoyltransferase I is not required for the oxidation of phytanic acid or pristanic acid, whereas both carnitine-acylcarnitine translocase and carnitine palmitoyltransferase II are necessary. These studies demonstrate that both phytanic acid and pristanic acid are initially oxidized in peroxisomes to 4,8-dimethylnonanoyl-CoA, which is converted to the corresponding acylcarnitine (presumably by peroxisomal carnitine octanoyltransferase), and exported to the mitochondrion. After transport across the mitochondrial membrane and transfer of the acylgroup to coenzyme A, further oxidation to 2,6-dimethylheptanoyl-CoA occurs.
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Affiliation(s)
- N M Verhoeven
- Department of Clinical Chemistry, Free University Hospital, Amsterdam, The Netherlands
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46
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47
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Abstract
A breast-fed female infant died suddenly in the neonatal period at 31 hours of age with profound macrovesicular fatty infiltration of liver, kidney, and muscle on postmortem examination, suggestive of a defect in fatty acid beta-oxidation. Fatty acid and palmitoyl-carnitine oxidation studies and direct enzyme study of cultured skin fibroblasts suggested a deficiency in the oxidation of long-chain fatty acids distal to carnitine palmitoyl-transferase I and before long-chain acyl-coenzyme A dehydrogenases. Deficient activity of carnitine-acylcarnitine translocase was demonstrated with intermediate levels of activity in the infant's parents, consistent with autosomal recessive inheritance. Fatty acid oxidation studies showed deficient oxidation of fatty acids at all chain lengths from C10:0 to C24:0, with partially reduced oxidation of C26:0 fatty acid, indicating the occurrence of a single mitochondrial carnitine-acylcarnitine translocase and demonstrating the requirement in vivo for L-carnitine for mitochondrial transport of all medium- and long-chain fatty acyl moieties. The disorder may have been precipitated in this breast-fed infant by poor initial feeding, fasting stress, and the long-chain triglycerides of human milk. The severity of the disorder prompted prenatal diagnosis, and affected siblings were excluded in two subsequent pregnancies by fatty acid oxidation in cultured chorionic villus cells and amniocytes.
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Affiliation(s)
- R A Chalmers
- Department of Child Health, St. George's Hospital Medical School, London, United Kingdom
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48
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Abstract
A newborn infant died suddenly and unexpectedly on day 5 of life. Postmortem investigations led to a suspicion of carnitine transporter deficiency, a diagnosis supported by the finding that both parents are heterozygotes for this disorder. The fasting stress caused by poor breast-feeding with no formula supplements and, possibly, the vegetarian diet of the mother were likely the critical factors leading to neonatal death, an outcome previously not described in this disorder.
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Affiliation(s)
- P Rinaldo
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8005, USA
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49
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Abstract
We report the first attempt at prenatal diagnosis of the carnitine transporter defect in a fetus at high risk of having the disorder. Analysis of cultured CVS after prolonged culture predicted that the fetus was not affected but might be heterozygous for the carnitine transporter defect, but chromosome 15 satellite DNA markers showed no paternal contribution, suggesting that the CVS cells assayed were of predominantly maternal origin. Subsequent assay of cultured amniocytes predicted that the fetus would be affected, and this was confirmed in the newborn period. We conclude that prenatal diagnosis of the carnitine transporter defect is possible, but where results depend on extended culture of CVS, molecular studies should be performed to confirm genetic contributions from both parents.
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Affiliation(s)
- J Christodoulou
- Department of Paediatrics and Child Health, University of Sydney, N.S.W., Australia
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50
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Brivet M, Slama A, Millington DS, Roe CR, Demaugre F, Legrand A, Boutron A, Poggi F, Saudubray JM. Retrospective diagnosis of carnitine-acylcarnitine translocase deficiency by acylcarnitine analysis in the proband Guthrie card and enzymatic studies in the parents. J Inherit Metab Dis 1996; 19:181-4. [PMID: 8739960 DOI: 10.1007/bf01799424] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- M Brivet
- Laboratoire de Biochimie, Hopital de Bicêtre, Le Kremlin-Bicetre, France
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