1
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Hegarty R, Thompson RJ. Genetic aetiologies of acute liver failure. J Inherit Metab Dis 2024; 47:582-597. [PMID: 38499319 DOI: 10.1002/jimd.12733] [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: 12/01/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/20/2024]
Abstract
Acute liver failure (ALF) is a rare, rapidly evolving, clinical syndrome with devastating consequences where definitive treatment is by emergency liver transplantation. Establishing a diagnosis can be challenging and, historically, the cause of ALF was unidentified in up to half of children. However, recent technological and clinical advances in genomic medicine have led to an increasing proportion being diagnosed with monogenic aetiologies of ALF. The conditions encountered include a diverse group of inherited metabolic disorders each with prognostic and treatment implications. Often these disorders are clinically indistinguishable and may even mimic disorders of immune regulation or red cell disorders. Rapid genomic sequencing for children with ALF is, therefore, a key component in the diagnostic work up today. This review focuses on the monogenic aetiologies of ALF.
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Affiliation(s)
- Robert Hegarty
- Paediatric Liver, GI and Nutrition Centre, King's College Hospital, London, UK
- Institute of Liver Studies, King's College London, London, UK
| | - Richard J Thompson
- Paediatric Liver, GI and Nutrition Centre, King's College Hospital, London, UK
- Institute of Liver Studies, King's College London, London, UK
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2
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Zhao C, Song Y, Zhang G, Zhang K, Yin S, Ji J. Multi-omics analysis identifies sex-specific hepatic protein-metabolite networks in yellow catfish (Pelteobagrus fulvidraco) exposed to chronic hypoxia. Int J Biol Macromol 2024; 268:131892. [PMID: 38677698 DOI: 10.1016/j.ijbiomac.2024.131892] [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: 12/12/2023] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 04/29/2024]
Abstract
Hypoxia disrupts the endocrine system of teleosts. The liver plays important roles in the endocrine system, energy storage, and metabolic processes. The aim of this study was to investigate the sex-specific hepatic response of yellow catfish under chronic hypoxia at the multi-omics level. Common hepatic responses in both sexes included the HIF-1 signaling pathway, glycolysis/gluconeogenesis, and steroid biosynthesis. Hypoxia dysregulated primary bile acid biosynthesis, lipid metabolism, and vitellogenin levels in female fish. Endoplasmic reticulum function in females also tended to be disrupted by hypoxia, as evidenced by significantly enriched pathways, including ribosome, protein processing in the endoplasmic reticulum, and RNA degradation. Other pathways, including the TCA cycle, oxidative phosphorylation, and Parkinson's and Huntington's disease, were highly enriched by hypoxia in male fish, suggesting that mitochondrial function was dysregulated. In both sexes of yellow catfish, the cell cycle was arrested and apoptosis was inhibited under chronic hypoxia. Multi-omics suggested that SLC2A5, CD209, LGMN, and NEDD8 served as sex-specific markers in these fish under chronic hypoxia. Our results provide insights into hepatic adaptation to chronic hypoxia and facilitate our understanding of sex-specific responses in fish.
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Affiliation(s)
- Cheng Zhao
- College of Marine Science and Engineering, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, China; Co-Innovation Center for Marine Bio-Industry Technology, Lian Yungang, Jiangsu, China
| | - Yufeng Song
- College of Marine Science and Engineering, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Guosong Zhang
- School of Agriculture and Bioengineering, Heze University, Heze, Shandong, China
| | - Kai Zhang
- College of Marine Science and Engineering, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, China; Co-Innovation Center for Marine Bio-Industry Technology, Lian Yungang, Jiangsu, China
| | - Shaowu Yin
- College of Marine Science and Engineering, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, China; Co-Innovation Center for Marine Bio-Industry Technology, Lian Yungang, Jiangsu, China.
| | - Jie Ji
- College of Marine Science and Engineering, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, China; Co-Innovation Center for Marine Bio-Industry Technology, Lian Yungang, Jiangsu, China.
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3
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Kirchberg I, Lainka E, Gangfuß A, Kuechler A, Baertling F, Schlieben LD, Lenz D, Tschiedel E. Distinct neonatal hyperammonemia and liver synthesis dysfunction: case report of a severe MEGDHEL syndrome. Front Pediatr 2024; 12:1278047. [PMID: 38445077 PMCID: PMC10912554 DOI: 10.3389/fped.2024.1278047] [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: 08/15/2023] [Accepted: 02/05/2024] [Indexed: 03/07/2024] Open
Abstract
Background/purpose MEGDHEL syndrome is a rare autosomal recessive metabolic disorder, which is characterized by 3-methylglutaconic aciduria with deafness-dystonia, hepatopathy, encephalopathy and Leigh-like syndrome. It is caused by biallelic pathogenic variants in the SERAC1 gene. Due to the unspecific symptoms and the diverse manifestations of the clinical phenotype, the diagnosis is challenging. Infantile MEGDHEL syndrome often has a severe disease course with acute liver failure. Differentiation from other metabolic disorders is difficult and requires a multidisciplinary approach. Case presentation A two-day-old small for gestational age neonate was admitted to our pediatric intensive care unit (PICU) due to severe liver failure with distinct hyperammonemia and hypoglycemia without elevation of transaminases or cholestasis. Due to high ammonia level, continuous hemodialysis was established immediately after admission. In addition, protein intake was stopped, and the patient anabolized with intravenous glucose. Temporary stabilization could be achieved after four days. In the further course, severe neurological and cardiocirculatory complications occurred, which ultimately led to the infant's death. In the metabolic diagnostics, a pronounced lactate acidosis and in urine an increased excretion of 3-methylglutaconic acid as well as other metabolites of mitochondrial energy metabolism has been the leading findings besides the hyperammonemia. Post-mortem trio whole genome analysis detected a homozygous pathogenic variant in SERAC1 with evidence of SERAC1 deficiency leading to the diagnosis of infantile MEGDHEL syndrome. Conclusion When pediatricians are faced with hepatopathy or even acute liver failure without elevation of transaminases or cholestasis in newborns, SERAC1 deficiency should be considered as a potential differential diagnosis. The initial treatment is based on the recommended management of suspected metabolic disorders. Even while no cure is available yet, patients should be offered proper supportive management through a multidisciplinary team. In addition, genetic confirmation of the diagnosis is important for the families, especially regarding further family planning.If a newborn presents with hyperammonemia, hypoglycemia and impaired liver synthesis function without elevation of transaminases or cholestasis, the possible presence of MEGDHEL syndrome due to a SERAC1 mutation should be considered.
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Affiliation(s)
- Ina Kirchberg
- Department of Pediatric Intensive Care, Children’s Hospital, University of Duisburg-Essen, Essen, Germany
| | - Elke Lainka
- Department of Pediatric Gastroenterology, Hepatology, and Transplant Medicine, Children’s Hospital, University Duisburg-Essen, Essen, Germany
| | - Andrea Gangfuß
- Department of Paediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioural Sciences, University Duisburg-Essen, Essen, Germany
| | - Alma Kuechler
- Institute of Human Genetics, University Hospital Essen, Essen, Germany
| | - Fabian Baertling
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children’s Hospital Duesseldorf, Heinrich Heine University, Dusseldorf, Germany
| | - Lea D. Schlieben
- School of Medicine, Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Institute of Neurogenomics, Computational Health Centre, Helmholtz Zentrum Muenchen, Neuherberg, Germany
| | - Dominic Lenz
- Division of Pediatric Neurology and Metabolic Medicine, Centre for Child and Adolescent Medicine, Heidelberg University, Medical Faculty, University Hospital Heidelberg, Heidelberg, Germany
| | - Eva Tschiedel
- Department of Pediatric Intensive Care, Children’s Hospital, University of Duisburg-Essen, Essen, Germany
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4
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Sun H, Zhang J, Ye Q, Jiang T, Liu X, Zhang X, Zeng F, Li J, Zheng Y, Han X, Su C, Shi Y. LPGAT1 controls MEGDEL syndrome by coupling phosphatidylglycerol remodeling with mitochondrial transport. Cell Rep 2023; 42:113214. [PMID: 37917582 PMCID: PMC10729602 DOI: 10.1016/j.celrep.2023.113214] [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: 05/08/2023] [Revised: 08/21/2023] [Accepted: 09/19/2023] [Indexed: 11/04/2023] Open
Abstract
Phosphatidylglycerol (PG) is a mitochondrial phospholipid required for mitochondrial cristae structure and cardiolipin synthesis. PG must be remodeled to its mature form at the endoplasmic reticulum (ER) after mitochondrial biosynthesis to achieve its biological functions. Defective PG remodeling causes MEGDEL (non-alcohol fatty liver disease and 3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like) syndrome through poorly defined mechanisms. Here, we identify LPGAT1, an acyltransferase that catalyzes PG remodeling, as a candidate gene for MEGDEL syndrome. We show that PG remodeling by LPGAT1 at the ER is closely coordinated with mitochondrial transport through interaction with the prohibitin/TIMM14 mitochondrial import motor. Accordingly, ablation of LPGAT1 or TIMM14 not only causes aberrant fatty acyl compositions but also ER retention of newly remodeled PG, leading to profound loss in mitochondrial crista structure and respiration. Consequently, genetic deletion of the LPGAT1 in mice leads to cardinal features of MEGDEL syndrome, including 3-methylglutaconic aciduria, deafness, dilated cardiomyopathy, and premature death, which are highly reminiscent of those caused by TIMM14 mutations in humans.
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Affiliation(s)
- Haoran Sun
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Jun Zhang
- Sam and Ann Barshop Institute for Longevity and Aging Studies, Department of Pharmacology, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX 78229, USA
| | - Qianqian Ye
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China; Sam and Ann Barshop Institute for Longevity and Aging Studies, Department of Pharmacology, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX 78229, USA
| | - Ting Jiang
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Xueling Liu
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Xiaoyang Zhang
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Fanyu Zeng
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China; Sam and Ann Barshop Institute for Longevity and Aging Studies, Department of Pharmacology, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX 78229, USA
| | - Jie Li
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Yue Zheng
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Xianlin Han
- Sam and Ann Barshop Institute for Longevity and Aging Studies, Department of Pharmacology, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX 78229, USA
| | - Chuan Su
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 101 Longmian Avenue, Nanjing, Jiangsu Province 211166, China
| | - Yuguang Shi
- Sam and Ann Barshop Institute for Longevity and Aging Studies, Department of Pharmacology, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX 78229, USA.
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5
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Joshi A, Richard TH, Gohil VM. Mitochondrial phospholipid metabolism in health and disease. J Cell Sci 2023; 136:jcs260857. [PMID: 37655851 PMCID: PMC10482392 DOI: 10.1242/jcs.260857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
Abstract
Studies of rare human genetic disorders of mitochondrial phospholipid metabolism have highlighted the crucial role that membrane phospholipids play in mitochondrial bioenergetics and human health. The phospholipid composition of mitochondrial membranes is highly conserved from yeast to humans, with each class of phospholipid performing a specific function in the assembly and activity of various mitochondrial membrane proteins, including the oxidative phosphorylation complexes. Recent studies have uncovered novel roles of cardiolipin and phosphatidylethanolamine, two crucial mitochondrial phospholipids, in organismal physiology. Studies on inter-organellar and intramitochondrial phospholipid transport have significantly advanced our understanding of the mechanisms that maintain mitochondrial phospholipid homeostasis. Here, we discuss these recent advances in the function and transport of mitochondrial phospholipids while describing their biochemical and biophysical properties and biosynthetic pathways. Additionally, we highlight the roles of mitochondrial phospholipids in human health by describing the various genetic diseases caused by disruptions in their biosynthesis and discuss advances in therapeutic strategies for Barth syndrome, the best-studied disorder of mitochondrial phospholipid metabolism.
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Affiliation(s)
- Alaumy Joshi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Travis H. Richard
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Vishal M. Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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6
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Baker MJ, Crameri JJ, Thorburn DR, Frazier AE, Stojanovski D. Mitochondrial biology and dysfunction in secondary mitochondrial disease. Open Biol 2022; 12:220274. [PMID: 36475414 PMCID: PMC9727669 DOI: 10.1098/rsob.220274] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial diseases are a broad, genetically heterogeneous class of metabolic disorders characterized by deficits in oxidative phosphorylation (OXPHOS). Primary mitochondrial disease (PMD) defines pathologies resulting from mutation of mitochondrial DNA (mtDNA) or nuclear genes affecting either mtDNA expression or the biogenesis and function of the respiratory chain. Secondary mitochondrial disease (SMD) arises due to mutation of nuclear-encoded genes independent of, or indirectly influencing OXPHOS assembly and operation. Despite instances of novel SMD increasing year-on-year, PMD is much more widely discussed in the literature. Indeed, since the implementation of next generation sequencing (NGS) techniques in 2010, many novel mitochondrial disease genes have been identified, approximately half of which are linked to SMD. This review will consolidate existing knowledge of SMDs and outline discrete categories within which to better understand the diversity of SMD phenotypes. By providing context to the biochemical and molecular pathways perturbed in SMD, we hope to further demonstrate the intricacies of SMD pathologies outside of their indirect contribution to mitochondrial energy generation.
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Affiliation(s)
- Megan J. Baker
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Jordan J. Crameri
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3052, Australia
| | - David R. Thorburn
- Murdoch Children's Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia,Victorian Clinical Genetics Services, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Ann E. Frazier
- Murdoch Children's Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Diana Stojanovski
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3052, Australia
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7
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Yuen L, Sahai I, O'Grady L, Selig M, Walker MA, Shah U, Misdraji J. Hepatic histologic findings in a case of MEGDHEL syndrome due to SERAC1 deficiency. Am J Med Genet A 2022; 188:2760-2765. [PMID: 35781780 DOI: 10.1002/ajmg.a.62886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 05/20/2022] [Accepted: 06/13/2022] [Indexed: 01/25/2023]
Abstract
MEGD(H)EL syndrome is a rare autosomal recessive disorder caused by mutations in SERAC1, a protein necessary for phosphatidylglycerol remodeling. It is characterized by 3-methylglutaconic aciduria, deafness-dystonia, (hepatopathy), encephalopathy, and Leigh-like syndrome, but has a wide spectrum of severity. Here, we present a case of a child with MEGD(H)EL syndrome with infantile hepatopathy, neurodevelopmental delays, characteristic biochemical abnormalities, and biallelic novel SERAC1 mutations: (1) deletion of (at least) exons 2-4, pathogenic; and (2) c.1601A>T (p.H534L), likely pathogenic. Her initial clinical presentation was notable for persistently elevated transaminases, speech delay, delayed motor milestones, and sensorineural hearing loss. However, her verbal and motor development has progressively improved and now, at 4 years of age, she has only speech and mild gross motor delays as compared to her unaffected peers and is exceeding clinical expectations. The histologic features of a liver biopsy are described, which has not previously been published in detail for this syndrome. Hepatocytes showed granular cytoplasm and fine intracytoplasmic lipid droplets. The ultrastructural findings included abnormal circular mitochondrial cristae. These findings are consistent with a mitochondrial disorder.
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Affiliation(s)
- Lisa Yuen
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Inderneel Sahai
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Medical Genetics and Metabolism, Massachusetts General Hospital for Children, Boston, Massachusetts, USA
| | - Lauren O'Grady
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Medical Genetics and Metabolism, Massachusetts General Hospital for Children, Boston, Massachusetts, USA
| | - Martin Selig
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Melissa Anne Walker
- Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Uzma Shah
- Harvard Medical School, Boston, Massachusetts, USA.,Department of Pediatric Gastroenterology, Massachusetts General Hospital for Children, Boston, Massachusetts, USA
| | - Joseph Misdraji
- Department of Pathology, Yale University, New Haven, Connecticut, USA
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8
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Du M, Li X, Xiao F, Fu Y, Shi Y, Guo S, Chen L, Shen L, Wang L, Cheng H, Li H, Xie A, Zhou Y, Yang K, Fang H, Lyu J, Zhao Q. Serine active site containing protein 1 depletion alters lipid metabolism and protects against high fat diet-induced obesity in mice. Metabolism 2022; 134:155244. [PMID: 35760118 DOI: 10.1016/j.metabol.2022.155244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/27/2022] [Accepted: 06/16/2022] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Although the serine active site containing 1 (SERAC1) protein is essential for cardiolipin remodeling and cholesterol transfer, its physiological role in whole-body energy metabolism remains unclear. Thus, we investigated the role of SERAC1 in lipid distribution and metabolism in mice. METHODS CRISPR/Cas9 was used to create homozygous Serac1 knockout mice. A range of methods, including electron microscopy, histological analysis, DNA sequencing, glucose and insulin tolerance tests, and biochemical analysis of serum lipid levels, were used to assess lipid distribution and rates of lipid synthesis in mice. RESULTS We found that Serac1 depletion in mice prevented high-fat diet-induced obesity but did not affect energy expenditure. The liver was affected by Serac1 depletion, but adipose tissues were not. Serac1 depletion was shown to impair cholesterol transfer from the liver to the serum and led to an imbalance in cholesterol distribution. The livers from mice with Serac1 depletion showed increased cholesterol synthesis because the levels of cholesterol synthesis enzymes were upregulated. Moreover, the accumulation of hepatic lipid droplets in mice with Serac1 depletion were decreased, suggesting that SERAC1 depletion may decrease the risk for hepatic steatosis in high fat diet-induced mice. CONCLUSION Our findings demonstrate that SERAC1 can serve as a potential target for the treatment or prevention of diet-induced hepatic lipid metabolic disorders.
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Affiliation(s)
- Miaomiao Du
- School of Laboratory Medicine and Bioengineering, Hangzhou Medical College, Hangzhou, Zhejiang 311399, China; Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province, Hangzhou, Zhejiang 310063, China; Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Xueyun Li
- Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University, Taizhou, Zhejiang 318000, China
| | - Fangyi Xiao
- Department of Cardiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325015, China
| | - Yinxu Fu
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yu Shi
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Sihan Guo
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Lifang Chen
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Lu Shen
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Lan Wang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Huang Cheng
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Hao Li
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Anran Xie
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yaping Zhou
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Kaiqiang Yang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Hezhi Fang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Jianxin Lyu
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China; Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, China.
| | - Qiongya Zhao
- School of Laboratory Medicine and Bioengineering, Hangzhou Medical College, Hangzhou, Zhejiang 311399, China; Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province, Hangzhou, Zhejiang 310063, China; Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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9
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Saneto RP, Perez FA. Mitochondria-Associated Membrane Scaffolding with Endoplasmic Reticulum: A Dynamic Pathway of Developmental Disease. Front Mol Biosci 2022; 9:908721. [PMID: 35775081 PMCID: PMC9237565 DOI: 10.3389/fmolb.2022.908721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Communication between intracellular organelles is essential for overall cellular function. How this communication occurs and under what circumstances alterations transpire are only the beginning to be elucidated. The pathways of calcium homeostasis, lipid transfer, mitochondrial dynamics, and mitophagy/apoptosis have been linked to the endoplasmic reticulum and tethering sites on the outer and/or inner mitochondrial membrane called mitochondria-associated endoplasmic reticulum membranes (MAM). Sensitive visualization by high-powered microscopy coupled with the advent of massive parallel sequencing has elaborated the structure, while patient’s diseases have uncovered the physiological function of these networks. Using specific patient examples from our pediatric mitochondrial center, we expand how specific genetic pathological variants in certain MAM structures induce disease. Genetic variants in MICU1, PASC-2, CYP2U1, SERAC1, and TANGO2 can induce early development abnormalities in the areas of cognition, motor, and central nervous system structures across multiple MAM pathways and implicate mitochondrial dysregulation.
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Affiliation(s)
- Russell P. Saneto
- Division of Pediatric Neurology, Department of Neurology, Seattle Children’s Hospital/University of Washington, Seattle, WA, United States
- Neuroscience Institute, Center for Integrated Brain Research, Seattle Children’s Hospital, Seattle, WA, United States
- *Correspondence: Russell P. Saneto,
| | - Francisco A. Perez
- Department of Radiology, Seattle Children’s Hospital/University of Washington, Seattle, WA, United States
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10
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Fang H, Xie A, Du M, Li X, Yang K, Fu Y, Yuan X, Fan R, Yu W, Zhou Z, Sang T, Nie K, Li J, Zhao Q, Chen Z, Yang Y, Hong C, Lyu J. SERAC1 is a component of the mitochondrial serine transporter complex required for the maintenance of mitochondrial DNA. Sci Transl Med 2022; 14:eabl6992. [PMID: 35235340 DOI: 10.1126/scitranslmed.abl6992] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
SERAC1 deficiency is associated with the mitochondrial 3-methylglutaconic aciduria with deafness, (hepatopathy), encephalopathy, and Leigh-like disease [MEGD(H)EL] syndrome, but the role of SERAC1 in mitochondrial physiology remains unknown. Here, we generated Serac1-/- mice that mimic the major diagnostic clinical and biochemical phenotypes of the MEGD(H)EL syndrome. We found that SERAC1 localizes to the outer mitochondrial membrane and is a protein component of the one-carbon cycle. By interacting with the mitochondrial serine transporter protein SFXN1, SERAC1 facilitated and was required for SFXN1-mediated serine transport from the cytosol to the mitochondria. Loss of SERAC1 impaired the one-carbon cycle and disrupted the balance of the nucleotide pool, which led to primary mitochondrial DNA (mtDNA) depletion in mice, HEK293T cells, and patient-derived immortalized lymphocyte cells due to insufficient supply of nucleotides. Moreover, both in vitro and in vivo supplementation of nucleosides/nucleotides restored mtDNA content and mitochondrial function. Collectively, our findings suggest that MEGD(H)EL syndrome shares both clinical and molecular features with the mtDNA depletion syndrome, and nucleotide supplementation may be an effective therapeutic strategy for MEGD(H)EL syndrome.
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Affiliation(s)
- Hezhi Fang
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Anran Xie
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Miaomiao Du
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou 310000, China.,Zhejiang Provincial People's Hospital, Affiliated People's Hospital of Hangzhou Medical College, Hangzhou 310000, China
| | - Xueyun Li
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China.,Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University, Taizhou 318000, China
| | - Kaiqiang Yang
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yinxu Fu
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiangshu Yuan
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Runxiao Fan
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Weidong Yu
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Zhuohua Zhou
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Tiantian Sang
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Ke Nie
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Jin Li
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Qiongya Zhao
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou 310000, China
| | - Zhehui Chen
- Department of Pediatrics, Peking University First Hospital, Beijing 100000, China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing 100000, China
| | - Chaoyang Hong
- Zhejiang Provincial People's Hospital, Affiliated People's Hospital of Hangzhou Medical College, Hangzhou 310000, China
| | - Jianxin Lyu
- Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China.,School of Laboratory Medicine, Hangzhou Medical College, Hangzhou 310000, China.,Zhejiang Provincial People's Hospital, Affiliated People's Hospital of Hangzhou Medical College, Hangzhou 310000, China
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11
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Fellman V, Banerjee R, Lin KL, Pulli I, Cooper H, Tyynismaa H, Kallijärvi J. Severe neonatal MEGDHEL syndrome with a homozygous truncating mutation in SERAC1. Biochim Biophys Acta Mol Basis Dis 2021; 1868:166298. [PMID: 34751152 DOI: 10.1016/j.bbadis.2021.166298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/08/2021] [Accepted: 10/25/2021] [Indexed: 01/10/2023]
Abstract
In the diagnostic work-up of a newborn infant with a metabolic crisis, lethal multiorgan failure on day six of life, and increased excretion of 3-methylglutaconic acid, we found using whole genome sequencing a homozygous SERAC1 mutation indicating MEGDHEL syndrome (3-methylglutaconic aciduria with deafness-dystonia, hepatopathy, encephalopathy, and Leigh-like syndrome). The SERAC1 protein is located at the contact site between mitochondria and the endoplasmic reticulum (ER) and is crucial for cholesterol trafficking. Our aim was to investigate the effect of the homozygous truncating mutation on mitochondrial structure and function. In the patient fibroblasts, no SERAC1 protein was detected, the mitochondrial network was severely fragmented, and the cristae morphology was altered. Filipin staining showed uneven localization of unesterified cholesterol. The calcium buffer function between cytoplasm and mitochondria was deficient. In liver mitochondria, complexes I, III, and IV were clearly decreased. In transfected COS-1 cells the mutant protein with the a 45-amino acid C-terminal truncation was distributed throughout the cell, whereas wild-type SERAC1 partially colocalized with the mitochondrial marker MT-CO1. The structural and functional mitochondrial abnormalities, caused by the loss of SERAC1, suggest that the crucial disease mechanism is disrupted interplay between the ER and mitochondria leading to decreased influx of calcium to mitochondria and secondary respiratory chain deficiency.
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Affiliation(s)
- Vineta Fellman
- Folkhälsan Research Center, Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland; Department of Clinical Sciences, Lund, Pediatrics, Lund University, Sweden; Children's Hospital, University of Helsinki, Finland.
| | - Rishi Banerjee
- Folkhälsan Research Center, Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | - Kai-Lan Lin
- Åbo Akademi University, Faculty of Natural Sciences and Technology, Turku, Finland
| | - Ilari Pulli
- Åbo Akademi University, Faculty of Natural Sciences and Technology, Turku, Finland
| | - Helen Cooper
- Åbo Akademi University, Faculty of Natural Sciences and Technology, Turku, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland; Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
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12
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Yan D, Chen S, Cai F, Shu J, Zhi X, Zheng J, Zhang C, Li D, Cai C. Complicated Hereditary Spastic Paraplegia Caused by SERAC1 Variants in a Chinese Family. Front Pediatr 2021; 9:816265. [PMID: 35223715 PMCID: PMC8873186 DOI: 10.3389/fped.2021.816265] [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: 11/16/2021] [Accepted: 12/31/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The serine active site-containing protein 1 (SERAC1) biallelic variant usually causes MEGDEL syndrome, clinically characterized by increased excretion of 3-methylglutaconic in the urine, muscle hypotonia, sensorineural deafness, and Leigh-like lesions on brain MRI scans. In this study, we present a case from a Chinese family with disordered metabolism and dystonia owing to SERAC1 variants; the clinical phenotypes of the proband were different from those of MEGDEL syndrome but were similar to those juvenile-onset complicated hereditary spastic paraplegia. Thus, in this study, we aimed to confirm the relationship between SERAC1 variants and complicated hereditary spastic paraplegia. METHODS MRI and laboratory tests, including gas chromatography/mass spectrometry (GC/MS), were carried out for the proband. Whole-exome sequencing was used to detect the candidate SERAC1 variants. Variants were verified using Sanger sequencing. Various software programs (PolyPhen-2, MutationTaster, PROVEAN, and SIFT) were used to predict the pathogenicity of novel variants. RESULTS Brain MRI scans showed a symmetric flake abnormal signal shadow in the bilateral basal ganglia in T2-weighted image (T2WI) and fluid-attenuated inversion recovery (FLAIR) analyses. The excretion of 3-methylglutaconic acid was found to be increased in our GC/MS analysis. Whole-exome sequencing showed novel compound heterozygous variants, including a novel c.1495A>G (p.Met499Val) variant in exon 14 of SERAC1 inherited from the father and a novel c.721_722delAG (p.Leu242fs) variant in exon 8 inherited from the mother. The pathogenicity prediction results showed that these two variants were deleterious. CONCLUSIONS This study presented a patient with complicated hereditary spastic paraplegia caused by SERAC1 variants. These findings expand the number of known SERAC1 variants and the phenotypic spectrum associated with SERAC1 deficiency. This study may contribute to counseling and prevention of hereditary diseases through prenatal.
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Affiliation(s)
- Dandan Yan
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China.,Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin, China
| | - Shaopei Chen
- Department of Neurology, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China
| | - Fengying Cai
- Department of Physiology, Tianjin Medical College, Tianjin, China
| | - Jianbo Shu
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China.,Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin, China
| | - Xiufang Zhi
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China.,Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin, China
| | - Jie Zheng
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China.,Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin, China
| | - Chunhua Zhang
- Matsumoto Institute of Life Science (MILS) International, Yokohama, Japan
| | - Dong Li
- Department of Neurology, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China
| | - Chunquan Cai
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Tianjin University Children's Hospital), Tianjin, China.,Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin, China
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13
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Finsterer J, Scorza FA, Fiorini AC, Scorza CA. MEGDEL Syndrome. Pediatr Neurol 2020; 110:25-29. [PMID: 32684373 DOI: 10.1016/j.pediatrneurol.2020.03.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/29/2020] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
MEGDEL syndrome is an autosomal recessive disorder, clinically characterized by 3-methylglutaconic aciduria, psychomotor delay, muscle hypotonia, sensorineural deafness, and Leigh-like lesions on brain magnetic resonance imaging. MEGDEL syndrome is due to mutations in the serine active site-containing protein 1 (SERAC1) gene. The SERAC1 protein is localized at the interface between the mitochondria and the endoplasmic reticulum in the mitochondrion-associated membrane fraction, which is essential for phospholipid exchange. SERAC1 was identified as a key player in phosphatidylglycerol remodeling, which is essential for both mitochondrial function and intracellular cholesterol trafficking. Since the first description of MEGDEL syndrome in 2006, at least 102 patients have been reported. The phenotypic spectrum of MEGDEL syndrome is much broader than so far anticipated. In addition to the brain, ears, and gastrointestinal tract, the eyes, endocrine organs, heart, peripheral nerves, and the skeletal muscle may be affected. Diagnosing MEGDEL syndrome requires a multidisciplinary approach, including genetic confirmation of a SERAC1 mutation. Treatment is supportive, and the outcome is usually poor with early death, except for the juvenile-onset type.
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Affiliation(s)
| | - Fulvio A Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina/Universidade Federal de São Paulo/, (EPM/UNIFESP), São Paulo, Brazil
| | - Ana C Fiorini
- Programa de Estudos Pós-Graduado em Fonoaudiologia, Pontifícia Universidade Católica de São Paulo (PUC-SP), Departamento de Fonoaudiologia, Escola Paulista de Medicina/Universidade Federal de São Paulo (EPM/UNIFESP), São Paulo, Brazil
| | - Carla A Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina/Universidade Federal de São Paulo/, (EPM/UNIFESP), São Paulo, Brazil
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14
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Alagoz M, Kherad N, Turkmen S, Bulut H, Yuksel A. A novel mutation in the SERAC1 gene correlates with the severe manifestation of the MEGDEL phenotype, as revealed by whole-exome sequencing. Exp Ther Med 2020; 19:3505-3512. [PMID: 32346411 PMCID: PMC7185166 DOI: 10.3892/etm.2020.8658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 01/10/2020] [Indexed: 11/05/2022] Open
Abstract
The condition 3-methylglutaconic aciduria (3-MGA) with deafness, encephalopathy and Leigh-like (MEGDEL) syndrome, also known as 3-MGA IV, is one of a group of five rare metabolic disorders characterized by mitochondrial dysfunction, resulting in a series of phenotypic abnormalities. It is a rare, recessive inherited disorder with a limited number of cases reported worldwide; hence, it is important to study each case to understand its genetic complexity. An impaired activity of serine active site-containing protein 1 (SERAC1), caused by mutations, leads to defects in phosphatidylglycerol remodelling, which is important for mitochondrial function and intracellular cholesterol trafficking. In the present study, the patients (two male siblings of consanguineous Turkish parents) were analysed, whose multisystem dysfunctions, including an elevated 3-MGA concentration in early age, hearing loss and Leigh-like syndrome as determined by MRI, were consistent with MEGDEL syndrome. A novel mutation in the SERAC1 gene, in the upstream lipase domain, c.1015G>C (p.Gly339Arg) mutation located on exon 10 of the SERAC1, was identified and predicted to cause protein dysfunction. Furthermore, the results pointed towards a possible association between this mutation and the severity of MEGDEL syndrome.
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Affiliation(s)
- Meryem Alagoz
- Department of Molecular Biology and Genetics, Genome Centre, Biruni University, Istanbul 34010, Turkey
| | - Nasim Kherad
- Department of Molecular Biology and Genetics, Genome Centre, Biruni University, Istanbul 34010, Turkey
| | - Selda Turkmen
- Department of Medical Biology, Istanbul Cerrahpasa University, Istanbul 34096, Turkey
| | - Hatice Bulut
- Faculty of Medicine, Biruni University Hospital, Istanbul 34010, Turkey
| | - Adnan Yuksel
- Faculty of Medicine, Biruni University Hospital, Istanbul 34010, Turkey
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15
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Vamecq J, Papegay B, Nuyens V, Boogaerts J, Leo O, Kruys V. Mitochondrial dysfunction, AMPK activation and peroxisomal metabolism: A coherent scenario for non-canonical 3-methylglutaconic acidurias. Biochimie 2019; 168:53-82. [PMID: 31626852 DOI: 10.1016/j.biochi.2019.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/10/2019] [Indexed: 12/13/2022]
Abstract
The occurrence of 3-methylglutaconic aciduria (3-MGA) is a well understood phenomenon in leucine oxidation and ketogenesis disorders (primary 3-MGAs). In contrast, its genesis in non-canonical (secondary) 3-MGAs, a growing-up group of disorders encompassing more than a dozen of inherited metabolic diseases, is a mystery still remaining unresolved for three decades. To puzzle out this anthologic problem of metabolism, three clues were considered: (i) the variety of disorders suggests a common cellular target at the cross-road of metabolic and signaling pathways, (ii) the response to leucine loading test only discriminative for primary but not secondary 3-MGAs suggests these latter are disorders of extramitochondrial HMG-CoA metabolism as also attested by their failure to increase 3-hydroxyisovalerate, a mitochondrial metabolite accumulating only in primary 3-MGAs, (iii) the peroxisome is an extramitochondrial site possessing its own pool and displaying metabolism of HMG-CoA, suggesting its possible involvement in producing extramitochondrial 3-methylglutaconate (3-MG). Following these clues provides a unifying common basis to non-canonical 3-MGAs: constitutive mitochondrial dysfunction induces AMPK activation which, by inhibiting early steps in cholesterol and fatty acid syntheses, pipelines cytoplasmic acetyl-CoA to peroxisomes where a rise in HMG-CoA followed by local dehydration and hydrolysis may lead to 3-MGA yield. Additional contributors are considered, notably for 3-MGAs associated with hyperammonemia, and to a lesser extent in CLPB deficiency. Metabolic and signaling itineraries followed by the proposed scenario are essentially sketched, being provided with compelling evidence from the literature coming in their support.
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Affiliation(s)
- Joseph Vamecq
- Inserm, CHU Lille, Univ Lille, Department of Biochemistry and Molecular Biology, Laboratory of Hormonology, Metabolism-Nutrition & Oncology (HMNO), Center of Biology and Pathology (CBP) Pierre-Marie Degand, CHRU Lille, EA 7364 RADEME, University of North France, Lille, France.
| | - Bérengère Papegay
- Laboratory of Experimental Medicine (ULB unit 222), University Hospital Center, Charleroi, (CHU Charleroi), Belgium
| | - Vincent Nuyens
- Laboratory of Experimental Medicine (ULB unit 222), University Hospital Center, Charleroi, (CHU Charleroi), Belgium
| | - Jean Boogaerts
- Laboratory of Experimental Medicine (ULB unit 222), University Hospital Center, Charleroi, (CHU Charleroi), Belgium
| | - Oberdan Leo
- Laboratory of Immunobiology, Department of Molecular Biology, ULB Immunology Research Center (UIRC), Free University of Brussels (ULB), Gosselies, Belgium
| | - Véronique Kruys
- Laboratory of Molecular Biology of the Gene, Department of Molecular Biology, ULB Immunology Research Center (UIRC), Free University of Brussels (ULB), Gosselies, Belgium
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16
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Snanoudj S, Mordel P, Dupas Q, Schanen C, Arion A, Gérard M, Read M, Nait Rabah D, Goux D, Chapon F, Jokic M, Allouche S. Identification of a novel splice site mutation in the SERAC1 gene responsible for the MEGDHEL syndrome. Mol Genet Genomic Med 2019; 7:e815. [PMID: 31251474 PMCID: PMC6687635 DOI: 10.1002/mgg3.815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/12/2019] [Accepted: 05/16/2019] [Indexed: 11/22/2022] Open
Abstract
Background MEGDHEL is an autosomal recessive syndrome defined as 3‐MEthylGlutaconic aciduria (3‐MGA) with Deafness, Hepatopathy, Encephalopathy, and Leigh‐like syndrome on magnetic resonance imaging, due to mutations in the SERAC1 (Serine Active Site Containing 1) gene, which plays a role in the mitochondrial cardiolipin metabolism. Methods We report the case of a young patient who presented with a convulsive encephalopathy, 3‐methylglutaconic aciduria, deafness, and bilateral T2 hypersignals of the putamen and the thalami, who passed away at 8 years of age. Results Analysis of nuclear genes using an ampliSeq™ targeted custom panel disclosed two compound heterozygous variants in the SERAC1 gene: a nonsense substitution in exon 4, c.202C>T, resulting in a premature stop codon (p.Arg68*), and a novel variant at a canonical splicing site upstream exon 4 (c.129‐1G>C). mRNAs sequencing from the fibroblasts of the patient showed that the splice site variant resulted in exon 3 skipping without frameshift while Western blot experiments showed the absence of SERAC1 expression compared to controls and abnormal filipin staining. Conclusion We showed that the loss of the putative transmembrane domain of SERAC1, due to a novel splice site variant, impairs the protein expression and is responsible for the MEGDHEL syndrome.
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Affiliation(s)
- Sarah Snanoudj
- Departments of BiochemistryUniversity Hospital of CaenCaenFrance
- Department of Medical geneticsUniversity Hospital of CaenCaenFrance
| | - Patrick Mordel
- Department of Signalisation, Électrophysiologie et Imagerie des Lésions d'Ischémie‐Reperfusion MyocardiqueNormandie Univ, UNICAENCaenFrance
| | - Quentin Dupas
- Department of Signalisation, Électrophysiologie et Imagerie des Lésions d'Ischémie‐Reperfusion MyocardiqueNormandie Univ, UNICAENCaenFrance
| | - Cécile Schanen
- Departments of BiochemistryUniversity Hospital of CaenCaenFrance
| | - Alina Arion
- Department of Medical pediatricsUniversity Hospital of CaenCaenFrance
| | - Marion Gérard
- Department of Medical geneticsUniversity Hospital of CaenCaenFrance
| | | | | | - Didier Goux
- CmaBio3, SF 4206 ICORE, Normandie Univ, UNICAENCaenFrance
| | | | - Mickael Jokic
- Department of Medico‐Surgical Pediatric Intensive Care UnitUniversity Hospital of CaenCaenFrance
| | - Stéphane Allouche
- Departments of BiochemistryUniversity Hospital of CaenCaenFrance
- Department of Signalisation, Électrophysiologie et Imagerie des Lésions d'Ischémie‐Reperfusion MyocardiqueNormandie Univ, UNICAENCaenFrance
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17
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Maas RR, Iwanicka‐Pronicka K, Kalkan Ucar S, Alhaddad B, AlSayed M, Al‐Owain MA, Al‐Zaidan HI, Balasubramaniam S, Barić I, Bubshait DK, Burlina A, Christodoulou J, Chung WK, Colombo R, Darin N, Freisinger P, Garcia Silva MT, Grunewald S, Haack TB, van Hasselt PM, Hikmat O, Hörster F, Isohanni P, Ramzan K, Kovacs‐Nagy R, Krumina Z, Martin‐Hernandez E, Mayr JA, McClean P, De Meirleir L, Naess K, Ngu LH, Pajdowska M, Rahman S, Riordan G, Riley L, Roeben B, Rutsch F, Santer R, Schiff M, Seders M, Sequeira S, Sperl W, Staufner C, Synofzik M, Taylor RW, Trubicka J, Tsiakas K, Unal O, Wassmer E, Wedatilake Y, Wolff T, Prokisch H, Morava E, Pronicka E, Wevers RA, de Brouwer AP, Wortmann SB. Progressive deafness-dystonia due to SERAC1 mutations: A study of 67 cases. Ann Neurol 2017; 82:1004-1015. [PMID: 29205472 PMCID: PMC5847115 DOI: 10.1002/ana.25110] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/13/2017] [Accepted: 11/26/2017] [Indexed: 11/12/2022]
Abstract
OBJECTIVE 3-Methylglutaconic aciduria, dystonia-deafness, hepatopathy, encephalopathy, Leigh-like syndrome (MEGDHEL) syndrome is caused by biallelic variants in SERAC1. METHODS This multicenter study addressed the course of disease for each organ system. Metabolic, neuroradiological, and genetic findings are reported. RESULTS Sixty-seven individuals (39 previously unreported) from 59 families were included (age range = 5 days-33.4 years, median age = 9 years). A total of 41 different SERAC1 variants were identified, including 20 that have not been reported before. With the exception of 2 families with a milder phenotype, all affected individuals showed a strikingly homogeneous phenotype and time course. Severe, reversible neonatal liver dysfunction and hypoglycemia were seen in >40% of all cases. Starting at a median age of 6 months, muscular hypotonia (91%) was seen, followed by progressive spasticity (82%, median onset = 15 months) and dystonia (82%, 18 months). The majority of affected individuals never learned to walk (68%). Seventy-nine percent suffered hearing loss, 58% never learned to speak, and nearly all had significant intellectual disability (88%). Magnetic resonance imaging features were accordingly homogenous, with bilateral basal ganglia involvement (98%); the characteristic "putaminal eye" was seen in 53%. The urinary marker 3-methylglutaconic aciduria was present in virtually all patients (98%). Supportive treatment focused on spasticity and drooling, and was effective in the individuals treated; hearing aids or cochlear implants did not improve communication skills. INTERPRETATION MEGDHEL syndrome is a progressive deafness-dystonia syndrome with frequent and reversible neonatal liver involvement and a strikingly homogenous course of disease. Ann Neurol 2017;82:1004-1015.
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Affiliation(s)
- Roeltje R. Maas
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenthe Netherlands
| | | | - Sema Kalkan Ucar
- Division of Metabolic Disease, Ege University Medical Faculty, Department of PediatricsIzmirTurkey
| | - Bader Alhaddad
- Institute of Human GeneticsTechnische UniversitätMünchenMunichGermany
| | - Moeenaldeen AlSayed
- Department of GeneticsKing Faisal Specialist Hospital and Research CenterRiyadhSaudi Arabia
- Department of Anatomy and Cell BiologyCollege of Medicine, Alfaisal UniversityRiyadhSaudi Arabia
| | - Mohammed A. Al‐Owain
- Department of GeneticsKing Faisal Specialist Hospital and Research CenterRiyadhSaudi Arabia
- Department of Anatomy and Cell BiologyCollege of Medicine, Alfaisal UniversityRiyadhSaudi Arabia
| | - Hamad I. Al‐Zaidan
- Department of GeneticsKing Faisal Specialist Hospital and Research CenterRiyadhSaudi Arabia
- Department of Anatomy and Cell BiologyCollege of Medicine, Alfaisal UniversityRiyadhSaudi Arabia
| | - Shanti Balasubramaniam
- Western Sydney Genetics Program, Children's Hospital at Westmead, SydneyNew South WalesAustralia
- Discipline of Genetic Medicine & Paediatrics and Child Health, University of SydneySydneyNew South WalesAustralia
| | - Ivo Barić
- Department of PediatricsUniversity Hospital CenterZagrebCroatia
- School of Medicine, University of ZagrebZagrebCroatia
| | - Dalal K. Bubshait
- Department of Pediatrics, College of MedicineImam Abdulrahman Bin Faisal UniversityDammamSaudi Arabia
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Department of PediatricsUniversity Hospital of PaduaPaduaItaly
| | - John Christodoulou
- Neurodevelopmental Genomics Research Group, Murdoch Children's Research Institute, and Department of PaediatricsMelbourne Medical School, University of MelbourneMelbourneVictoriaAustralia
- Genetic Metabolic Disorders Research Unit and Western Sydney Genetics Program, Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of Child and Adolescent Health and Genetic Medicine, Sydney Medical School, University of SydneySydneyNew South WalesAustralia
| | - Wendy K. Chung
- Departments of Pediatrics and MedicineColumbia UniversityNew YorkNY
| | - Roberto Colombo
- Institute of Clinical Biochemistry, Faculty of Medicine, Catholic University of the Sacred HeartRomeItaly
- Center for the Study of Rare Hereditary Diseases, Niguarda Ca' Granda Metropolitan HospitalMilanItaly
| | - Niklas Darin
- Department of PediatricsInstitute of Clinical Sciences, University of Gothenburg, Queen Silvia's Children's HospitalGothenburgSweden
| | | | - Maria Teresa Garcia Silva
- Inborn Errors of Metabolism and Mitochondrial Disease Unit“12 de Octubre” University Hospital, Avenida de Cordoba sn, 28041 Madrid, Spain. Rare Diseases Biomedical Research Centre (CIBERER)MadridSpain
- Complutense UniversityMadridSpain
| | - Stephanie Grunewald
- Metabolic Medicine DepartmentGreat Ormond Street Hospital for Children National Health Service Foundation Trust, University College London Institute of Child HealthLondonUnited Kingdom
| | - Tobias B. Haack
- Institute of Human GeneticsTechnische UniversitätMünchenMunichGermany
- Institute of Medical Genetics and Applied GenomicsTübingenGermany
| | - Peter M. van Hasselt
- Wilhelmina Children's Hospital Utrecht, University Medical Center UtrechtUtrechtthe Netherlands
| | - Omar Hikmat
- Department of PediatricsHaukeland University HospitalBergenNorway
- Department of Clinical Medicine (K1)University of BergenBergenNorway
| | - Friederike Hörster
- Department of General Pediatrics, Division of Neuropediatrics and Pediatric Metabolic MedicineUniversity Hospital HeidelbergHeidelbergGermany
| | - Pirjo Isohanni
- Children's Hospital, University of Helsinki and Helsinki University HospitalHelsinkiFinland
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of HelsinkiHelsinkiFinland
| | - Khushnooda Ramzan
- Department of GeneticsKing Faisal Specialist Hospital and Research CenterRiyadhSaudi Arabia
- Department of Anatomy and Cell BiologyCollege of Medicine, Alfaisal UniversityRiyadhSaudi Arabia
| | - Reka Kovacs‐Nagy
- Institute of Human GeneticsTechnische UniversitätMünchenMunichGermany
| | - Zita Krumina
- Department of Biology and MicrobiologyRiga Stradin's UniversityRigaLatvia
| | - Elena Martin‐Hernandez
- Inborn Errors of Metabolism and Mitochondrial Disease Unit“12 de Octubre” University Hospital, Avenida de Cordoba sn, 28041 Madrid, Spain. Rare Diseases Biomedical Research Centre (CIBERER)MadridSpain
- Complutense UniversityMadridSpain
| | - Johannes A. Mayr
- Department of PediatricsSalzburg State Hospitals and Paracelsus Medical UniversitySalzburgAustria
| | - Patricia McClean
- Leeds Teaching Hospitals National Health Service TrustLeedsUnited Kingdom
| | | | - Karin Naess
- Department of Pediatric NeurologyKarolinska University HospitalStockholmSweden
| | - Lock H. Ngu
- Division of Clinical Genetics, Department of GeneticsKuala Lumpur HospitalKuala LumpurMalaysia
| | - Magdalena Pajdowska
- Department of Clinical Biochemistry, Radioimmunology, and Experimental MedicineChildren's Memorial Health InstituteWarsawPoland
| | - Shamima Rahman
- University College London Great Ormond Street Institute of Child HealthLondonUnited Kingdom
| | - Gillian Riordan
- Department of Pediatric NeurologyRed Cross War Memorial Children's HospitalCape TownSouth Africa
| | - Lisa Riley
- Genetic Metabolic Disorders Research Unit and Western Sydney Genetics Program, Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of Child and Adolescent Health and Genetic Medicine, Sydney Medical School, University of SydneySydneyNew South WalesAustralia
| | - Benjamin Roeben
- Department of NeurodegenerationHertie Institute for Clinical Brain Research, University of TübingenTübingenGermany
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
| | - Frank Rutsch
- Department of General PediatricsMünster University Children's HospitalMünsterGermany
| | - Rene Santer
- Department of PediatricsUniversity Medical Center EppendorfHamburgGermany
| | - Manuel Schiff
- Reference Center for Inherited Metabolic Diseases, AP‐HP, Robert Debré Hospital, University Paris Diderot‐Sorbonne Paris Cité, Paris, France AND INSERM U1141ParisFrance
| | - Martine Seders
- Department of Human GeneticsRadboud University Medical CenterNijmegenthe Netherlands
| | | | - Wolfgang Sperl
- Department of PediatricsSalzburg State Hospitals and Paracelsus Medical UniversitySalzburgAustria
| | - Christian Staufner
- Department of General Pediatrics, Division of Neuropediatrics and Pediatric Metabolic MedicineUniversity Hospital HeidelbergHeidelbergGermany
| | - Matthis Synofzik
- Department of NeurodegenerationHertie Institute for Clinical Brain Research, University of TübingenTübingenGermany
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial ResearchInstitute of Neuroscience, The Medical School, Newcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Joanna Trubicka
- Department of Medical GeneticsChildren's Memorial Health InstituteWarsawPoland
| | | | - Ozlem Unal
- Division of Metabolic DiseasesHacettepe University Children's HospitalAnkaraTurkey
| | | | - Yehani Wedatilake
- University College London Great Ormond Street Institute of Child HealthLondonUnited Kingdom
| | - Toni Wolff
- Nottingham University Hospitals National Health Service Trust, Nottingham Children's HospitalNottinghamUnited Kingdom
| | - Holger Prokisch
- Institute of Human GeneticsTechnische UniversitätMünchenMunichGermany
- Institute of Human Genetics, Helmholtz Center MunichNeuherbergGermany
| | - Eva Morava
- Hayward Genetics Center and Department of PediatricsTulane University Medical SchoolNew OrleansLA
| | - Ewa Pronicka
- Department of Pediatrics, Nutrition and Metabolic DiseasesChildren's Memorial Health InstituteWarsawPoland
| | - Ron A. Wevers
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenthe Netherlands
| | - Arjan P. de Brouwer
- Department of Human GeneticsRadboud University Medical CenterNijmegenthe Netherlands
- Donders Institute for Brain, Cognition, and Behavior, Radboud University Medical CenterNijmegenthe Netherlands
| | - Saskia B. Wortmann
- Institute of Human GeneticsTechnische UniversitätMünchenMunichGermany
- Department of PediatricsSalzburg State Hospitals and Paracelsus Medical UniversitySalzburgAustria
- Institute of Human Genetics, Helmholtz Center MunichNeuherbergGermany
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18
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Radha Rama Devi A, Lingappa L. Novel mutations in SERAC1 gene in two Indian patients presenting with dystonia and intellectual disability. Eur J Med Genet 2017; 61:100-103. [PMID: 28778788 DOI: 10.1016/j.ejmg.2017.07.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 07/06/2017] [Accepted: 07/30/2017] [Indexed: 11/18/2022]
Abstract
In this study we present the first two cases from India of a rare inborn error of metabolism manifesting as dystonia and 3-methylglutaconic aciduria and a Leigh like lesions in the brain MRI associated with SERAC1 gene mutation, a phenotype characteristic of MEGDEL syndrome. A four base pair duplication in exon 15 i.e.NM_032861.3 (SERAC1) c. 1643_1646 dup ATCT (p.(Leu550SerfsX19)) and another with a homozygous missense variation in exon 15 i.e. NM_032861.3 (SERAC1) c.1709 G > A (p.(Gly526Glu)) were detected and both were novel mutations. Hepatopathy was observed in the neonatal period with lactic acidosis in one child and at the age of 5yrs in the other. These cases add to the existing number of patients identified till today and additional mutations in the SERAC1 gene.
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Affiliation(s)
- A Radha Rama Devi
- Sandor Life Sciences & Rainbow Children Hospital, Perinatal Centre for Women and Children, Road No 3, Banjara Hills, Hyderabad, 500082, India.
| | - Lokesh Lingappa
- Paediatric Neurologist, Rainbow Children Hospital, Hyderabad, 500082, India
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19
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Rokicki D, Pajdowska M, Trubicka J, Thong MK, Ciara E, Piekutowska-Abramczuk D, Pronicki M, Sikora R, Haidar R, Ołtarzewski M, Jabłońska E, Muthukumarasamy P, Sthaneswar P, Gan CS, Krajewska-Walasek M, Carrozzo R, Verrigni D, Semeraro M, Rizzo C, Taurisano R, Alhaddad B, Kovacs-Nagy R, Haack TB, Dionisi-Vici C, Pronicka E, Wortmann SB. 3-Methylglutaconic aciduria, a frequent but underrecognized finding in carbamoyl phosphate synthetase I deficiency. Clin Chim Acta 2017; 471:95-100. [DOI: 10.1016/j.cca.2017.05.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 12/16/2022]
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20
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Theunissen TEJ, Sallevelt SCEH, Hellebrekers DMEI, de Koning B, Hendrickx ATM, van den Bosch BJC, Kamps R, Schoonderwoerd K, Szklarczyk R, Mulder-Den Hartog ENM, de Coo IFM, Smeets HJM. Rapid Resolution of Blended or Composite Multigenic Disease in Infants by Whole-Exome Sequencing. J Pediatr 2017; 182:371-374.e2. [PMID: 28081892 DOI: 10.1016/j.jpeds.2016.12.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/24/2016] [Accepted: 12/09/2016] [Indexed: 11/17/2022]
Abstract
Whole-exome sequencing identified multiple genetic causes in 2 infants with heterogeneous disease. Three gene defects in the first patient explained all symptoms, but manifestations were overlapping (blended phenotype). Two gene defects in the second patient explained nonoverlapping symptoms (composite phenotype). Whole-exome sequencing rapidly and comprehensively resolves heterogeneous genetic disease.
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Affiliation(s)
- Tom E J Theunissen
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Genetics and Cell Biology, School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Debby M E I Hellebrekers
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Bart de Koning
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Alexandra T M Hendrickx
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Bianca J C van den Bosch
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Rick Kamps
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Kees Schoonderwoerd
- Department of Clinical Genetics, Erasmus Medical Centre (MC), Rotterdam, The Netherlands
| | - Radek Szklarczyk
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | | | | | - Hubert J M Smeets
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Genetics and Cell Biology, School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.
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21
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Abstract
Mitochondrial disorders (MIDs) due to respiratory-chain defects or nonrespiratory chain defects are usually multisystem conditions [mitochondrial multiorgan disorder syndrome (MIMODS)] affecting the central nervous system (CNS), peripheral nervous system, eyes, ears, endocrine organs, heart, kidneys, bone marrow, lungs, arteries, and also the intestinal tract. Frequent gastrointestinal (GI) manifestations of MIDs include poor appetite, gastroesophageal sphincter dysfunction, constipation, dysphagia, vomiting, gastroparesis, GI pseudo-obstruction, diarrhea, or pancreatitis and hepatopathy. Rare GI manifestations of MIDs include dry mouth, paradontosis, tracheoesophageal fistula, stenosis of the duodeno-jejunal junction, atresia or imperforate anus, liver cysts, pancreas lipomatosis, pancreatic cysts, congenital stenosis or obstruction of the GI tract, recurrent bowel perforations with intra-abdominal abscesses, postprandial abdominal pain, diverticulosis, or pneumatosis coli. Diagnosing GI involvement in MIDs is not at variance from diagnosing GI disorders due to other causes. Treatment of mitochondrial GI disease includes noninvasive or invasive measures. Therapy is usually symptomatic. Only for myo-neuro-gastro-intestinal encephalopathy is a causal therapy with autologous stem-cell transplantation available. It is concluded that GI manifestations of MIDs are more widespread than so far anticipated and that they must be recognized as early as possible to initiate appropriate diagnostic work-up and avoid any mitochondrion-toxic treatment.
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Affiliation(s)
| | - Marlies Frank
- First Medical Department, Krankenanstalt Rudolfstiftung, Vienna, Austria
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22
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Nuebel E, Manganas P, Tokatlidis K. Orphan proteins of unknown function in the mitochondrial intermembrane space proteome: New pathways and metabolic cross-talk. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2613-2623. [PMID: 27425144 PMCID: PMC5404111 DOI: 10.1016/j.bbamcr.2016.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/07/2016] [Accepted: 07/12/2016] [Indexed: 12/14/2022]
Abstract
The mitochondrial intermembrane space (IMS) is involved in protein transport, lipid homeostasis and metal ion exchange, while further acting in signalling pathways such as apoptosis. Regulation of these processes involves protein modifications, as well as stress-induced import or release of proteins and other signalling molecules. Even though the IMS is the smallest sub-compartment of mitochondria, its redox state seems to be tightly regulated. However, the way in which this compartment participates in the cross-talk between the multiple organelles and the cytosol is far from understood. Here we focus on newly identified IMS proteins that may represent future challenges in mitochondrial research. We present an overview of the import pathways, the recently discovered new components of the IMS proteome and how these relate to key aspects of cell signalling and progress made in stem cell and cancer research. A brief overview of the classic mitochondrial import pathways is featured Recent studies assigning a number of new proteins to the mitochondrial IMS are discussed Analysis of the expanded IMS proteomes can provide insights into organelle cross-talk and signalling pathways
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Affiliation(s)
- Esther Nuebel
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Phanee Manganas
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Kostas Tokatlidis
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
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23
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Harbulot C, Paquay S, Dorboz I, Pichard S, Bourillon A, Benoist JF, Jardel C, Ogier de Baulny H, Boespflug-Tanguy O, Schiff M. Transient neonatal renal failure and massive polyuria in MEGDEL syndrome. Mol Genet Metab Rep 2016; 7:8-10. [PMID: 27331002 PMCID: PMC4908062 DOI: 10.1016/j.ymgmr.2016.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/03/2016] [Accepted: 03/03/2016] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND MEGDEL (3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like syndrome) syndrome is a mitochondrial disorder associated with recessive mutations in SERAC1. OBJECTIVES To report transient neonatal renal findings in MEGDEL syndrome. RESULTS This 7 year-old girl was the first child of consanguineous Turkish parents. She exhibited an acute neonatal deterioration with severe lactic acidosis and liver failure. Initial evaluation revealed massive polyuria and renal failure with 3-methylglutaconic aciduria. Symptoms and biological findings progressively improved with symptomatic treatment but lactic acidosis and high lactate to pyruvate ratio along with 3-methylglutaconic aciduria persisted. At 8 months of age, a subacute neurological degradation occurred with severe hypotonia, dystonia with extrapyramidal movements and failure to thrive. Brain MRI revealed basal ganglia lesions suggestive of Leigh syndrome. At 3 years of age, sensorineural deafness was documented. MEGDEL syndrome was further confirmed by the identification of an already reported homozygous mutation in SERAC1. CONCLUSION Transient neonatal polyuria and renal failure have not been reported to date in SERAC1 defective patients. Such neonatal kidney findings expand the clinical spectrum of MEGDEL syndrome.
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Affiliation(s)
| | - Stéphanie Paquay
- Child Neurology, Hôpital Robert Debré, APHP, Paris, France; Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
| | - Imen Dorboz
- Inserm U1141 and Université Paris-Diderot, Sorbonne Paris Cité, site Robert Debré, Paris, France
| | - Samia Pichard
- Child Neurology, Hôpital Robert Debré, APHP, Paris, France; Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
| | | | | | - Claude Jardel
- Biochemistry, Hôpital de la Salpêtrière, APHP, Paris, France
| | - Hélène Ogier de Baulny
- Child Neurology, Hôpital Robert Debré, APHP, Paris, France; Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
| | - Odile Boespflug-Tanguy
- Child Neurology, Hôpital Robert Debré, APHP, Paris, France; Inserm U1141 and Université Paris-Diderot, Sorbonne Paris Cité, site Robert Debré, Paris, France
| | - Manuel Schiff
- Child Neurology, Hôpital Robert Debré, APHP, Paris, France; Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France; Inserm U1141 and Université Paris-Diderot, Sorbonne Paris Cité, site Robert Debré, Paris, France
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24
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Wedatilake Y, Plagnol V, Anderson G, Paine SML, Clayton PT, Jacques TS, Rahman S. Tubular aggregates caused by serine active site containing 1 (SERAC1) mutations in a patient with a mitochondrial encephalopathy. Neuropathol Appl Neurobiol 2015; 41:399-402. [PMID: 25345337 PMCID: PMC4964926 DOI: 10.1111/nan.12190] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 10/21/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Yehani Wedatilake
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
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25
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First missense mutation outside of SERAC1 lipase domain affecting intracellular cholesterol trafficking. Neurogenetics 2015; 17:51-6. [PMID: 26445863 DOI: 10.1007/s10048-015-0463-z] [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: 09/17/2015] [Accepted: 09/21/2015] [Indexed: 10/23/2022]
Abstract
We report the clinical and genetic findings in a Spanish boy who presented MEGDEL syndrome, a very rare inborn error of metabolism. Whole-exome sequencing uncovered a new homozygous mutation in the serine active site containing 1 (SERAC1) gene, which is essential for both mitochondrial function and intracellular cholesterol trafficking. Functional studies in patient fibroblasts showed that p.D224G mutation affects the intracellular cholesterol trafficking. Only three missense mutations in this gene have been described before, being p.D224G the first missense mutation outside of the SERAC1 serine-lipase domain. Therefore, we conclude that the defect in cholesterol trafficking is not limited to alterations in this specific part of the protein.
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26
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Dweikat IM, Abdelrazeq S, Ayesh S, Jundi T. MEGDEL Syndrome in a Child From Palestine: Report of a Novel Mutation in SERAC1 Gene. J Child Neurol 2015; 30:1053-6. [PMID: 25051967 DOI: 10.1177/0883073814541474] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 06/01/2014] [Indexed: 11/16/2022]
Abstract
We report the first Palestinian child manifesting with 3-methylglutaconic aciduria psychomotor delay, muscle hypotonia, sensori-neural deafness, and Leigh-like lesions on brain magnetic resonance imaging (MRI), a clinical phenotype that is characteristic of MEGDEL syndrome. MEGDEL syndrome was recently found to be caused by mutations in SERAC1, encoding a protein essential for mitochondrial function, phospholipid remodeling, and intracellular cholesterol trafficking. We identified a novel homozygous mutation in SERAC1 gene (c.1018delT) that generates frame shift and premature termination of protein translation. Plasma and cerebrospinal fluid lactate, plasma alanine, and respiratory chain complexes in fresh muscle were normal. This report further expands the genetic spectrum of MEGDEL syndrome and adds to the evidence that it is associated with variable patterns of respiratory chain abnormalities.
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Affiliation(s)
- Imad M Dweikat
- An-Najah National University, Metabolic. Faculty of Medicine and Health Sciences, Nablus
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27
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Lu YW, Claypool SM. Disorders of phospholipid metabolism: an emerging class of mitochondrial disease due to defects in nuclear genes. Front Genet 2015; 6:3. [PMID: 25691889 PMCID: PMC4315098 DOI: 10.3389/fgene.2015.00003] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/06/2015] [Indexed: 01/14/2023] Open
Abstract
The human nuclear and mitochondrial genomes co-exist within each cell. While the mitochondrial genome encodes for a limited number of proteins, transfer RNAs, and ribosomal RNAs, the vast majority of mitochondrial proteins are encoded in the nuclear genome. Of the multitude of mitochondrial disorders known to date, only a fifth are maternally inherited. The recent characterization of the mitochondrial proteome therefore serves as an important step toward delineating the nosology of a large spectrum of phenotypically heterogeneous diseases. Following the identification of the first nuclear gene defect to underlie a mitochondrial disorder, a plenitude of genetic variants that provoke mitochondrial pathophysiology have been molecularly elucidated and classified into six categories that impact: (1) oxidative phosphorylation (subunits and assembly factors); (2) mitochondrial DNA maintenance and expression; (3) mitochondrial protein import and assembly; (4) mitochondrial quality control (chaperones and proteases); (5) iron–sulfur cluster homeostasis; and (6) mitochondrial dynamics (fission and fusion). Here, we propose that an additional class of genetic variant be included in the classification schema to acknowledge the role of genetic defects in phospholipid biosynthesis, remodeling, and metabolism in mitochondrial pathophysiology. This seventh class includes a small but notable group of nuclear-encoded proteins whose dysfunction impacts normal mitochondrial phospholipid metabolism. The resulting human disorders present with a diverse array of pathologic consequences that reflect the variety of functions that phospholipids have in mitochondria and highlight the important role of proper membrane homeostasis in mitochondrial biology.
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Affiliation(s)
- Ya-Wen Lu
- Department of Physiology, School of Medicine, Johns Hopkins University Baltimore, MD, USA
| | - Steven M Claypool
- Department of Physiology, School of Medicine, Johns Hopkins University Baltimore, MD, USA
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28
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Garcia-Cazorla À, Mochel F, Lamari F, Saudubray JM. The clinical spectrum of inherited diseases involved in the synthesis and remodeling of complex lipids. A tentative overview. J Inherit Metab Dis 2015; 38:19-40. [PMID: 25413954 DOI: 10.1007/s10545-014-9776-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/16/2014] [Accepted: 09/23/2014] [Indexed: 12/19/2022]
Abstract
Over one hundred diseases related to inherited defects of complex lipids synthesis and remodeling are now reported. Most of them were described within the last 5 years. New descriptions and phenotypes are expanding rapidly. While the associated clinical phenotype is currently difficult to outline, with only a few patients identified, it appears that all organs and systems may be affected. The main clinical presentations can be divided into (1) Diseases affecting the central and peripheral nervous system. Complex lipid synthesis disorders produce prominent motor manifestations due to upper and/or lower motoneuron degeneration. Motor signs are often complex, associated with other neurological and extra-neurological signs. Three neurological phenotypes, spastic paraparesis, neurodegeneration with brain iron accumulation and peripheral neuropathies, deserve special attention. Many apparently well clinically defined syndromes are not distinct entities, but rather clusters on a continuous spectrum, like for the PNPLA6-associated diseases, extending from Boucher-Neuhauser syndrome via Gordon Holmes syndrome to spastic ataxia and pure hereditary spastic paraplegia; (2) Muscular/cardiac presentations; (3) Skin symptoms mostly represented by syndromic (neurocutaneous) and non syndromic ichthyosis; (4) Retinal dystrophies with syndromic and non syndromic retinitis pigmentosa, Leber congenital amaurosis, cone rod dystrophy, Stargardt disease; (5) Congenital bone dysplasia and segmental overgrowth disorders with congenital lipomatosis; (6) Liver presentations characterized mainly by transient neonatal cholestatic jaundice and non alcoholic liver steatosis with hypertriglyceridemia; and (7) Renal and immune presentations. Lipidomics and molecular functional studies could help to elucidate the mechanism(s) of dominant versus recessive inheritance observed for the same gene in a growing number of these disorders.
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Affiliation(s)
- Àngels Garcia-Cazorla
- Department of Neurology, Neurometabolic Unit, Hospital Sant Joan de Déu and CIBERER, ISCIII, Barcelona, Spain,
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29
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Lamari F, Mochel F, Saudubray JM. An overview of inborn errors of complex lipid biosynthesis and remodelling. J Inherit Metab Dis 2015; 38:3-18. [PMID: 25238787 DOI: 10.1007/s10545-014-9764-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/08/2014] [Accepted: 08/14/2014] [Indexed: 01/10/2023]
Abstract
In a review published in 2012, we delineated 14 inborn errors of metabolism (IEM) related to defects in biosynthesis of complex lipids, particularly phospholipids and sphingolipids (Lamari et al 2013). Given the numerous roles played by these molecules in membrane integrity, cell structure and function, this group of diseases is rapidly expanding as predicted. Almost 40 new diseases related to genetic defects in enzymes involved in the biosynthesis and remodelling of phospholipids, sphingolipids and complex fatty acids are now reported. While the clinical phenotype associated with these defects is currently difficult to outline, with only a few patients identified to date, it appears that all organs and systems may be affected - central and peripheral nervous system, eye, muscle, skin, bone, liver, immune system, etc. This chapter presents an introductive overview of this new group of IEM. More broadly, this special issue provides an update on other IEM involving complex lipids, namely dolichol and isoprenoids, glycolipids and congenital disorders of glycosylation, very long chain fatty acids and plasmalogens. Likewise, more than 100 IEM may actually lead to primary or secondary defects of complex lipids synthesis and remodelling. Because of the implication of several cellular compartments, this new group of disorders affecting the synthesis and remodelling of complex molecules challenges our current classification of IEM still largely based on cellular organelles--i.e. mitochondrial, lysosomal, peroxisomal disorders. While most of these new disorders have been identified by next generation sequencing, we wish to emphasize the promising role of lipidomics in deciphering their pathophysiology and identifying therapeutic targets.
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Affiliation(s)
- Foudil Lamari
- Bioclinic and Genetic Unit of Neurometabolic Diseases, Pitié-Salpêtrière Hospital, (APHP), Paris, 75013, France
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30
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Wortmann SB, Espeel M, Almeida L, Reimer A, Bosboom D, Roels F, de Brouwer APM, Wevers RA. Inborn errors of metabolism in the biosynthesis and remodelling of phospholipids. J Inherit Metab Dis 2015; 38:99-110. [PMID: 25178427 DOI: 10.1007/s10545-014-9759-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 11/24/2022]
Abstract
Since the proposal to define a separate subgroup of inborn errors of metabolism involved in the biosynthesis and remodelling of phospholipids, sphingolipids and long chain fatty acids in 2013, this group is rapidly expanding. This review focuses on the disorders involved in the biosynthesis of phospholipids. Phospholipids are involved in uncountable cellular processes, e.g. as structural components of membranes, by taking part in vesicle and mitochondrial fusion and fission or signal transduction. Here we provide an overview on both pathophysiology and the extremely heterogeneous clinical presentations of the disorders reported so far (Sengers syndrome (due to mutations in AGK), MEGDEL syndrome (or SERAC defect, SERAC1), Barth syndrome (or TAZ defect, TAZ), congenital muscular dystrophy due to CHKB deficiency (CHKB). Boucher-Neuhäuser/Gordon Holmes syndrome (PNPLA6), PHARC syndrome (ABHD12), hereditary spastic paraplegia type 28, 54 and 56 (HSP28, DDHD1; HSP54, DDHD2; HSP56, CYP2U1), Lenz Majewski syndrome (PTDSS1), spondylometaphyseal dysplasia with cone-rod dystrophy (PCYT1A), atypical haemolytic-uremic syndrome due to DGKE deficiency (DGKE).
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Affiliation(s)
- Saskia B Wortmann
- Nijmegen Centre for Mitochondrial Disorders (NCMD) at the Amalia Children's Hospital, Radboudumc, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands,
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31
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Mitochondria in peroxisome-deficient hepatocytes exhibit impaired respiration, depleted DNA, and PGC-1α independent proliferation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:285-98. [PMID: 25450972 DOI: 10.1016/j.bbamcr.2014.11.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/04/2014] [Accepted: 11/13/2014] [Indexed: 02/01/2023]
Abstract
The tight interrelationship between peroxisomes and mitochondria is illustrated by their cooperation in lipid metabolism, antiviral innate immunity and shared use of proteins executing organellar fission. In addition, we previously reported that disruption of peroxisome biogenesis in hepatocytes severely impacts on mitochondrial integrity, primarily damaging the inner membrane. Here we investigated the molecular impairments of the dysfunctional mitochondria in hepatocyte selective Pex5 knockout mice. First, by using blue native electrophoresis and in-gel activity stainings we showed that the respiratory complexes were differentially affected with reduction of complexes I and III and incomplete assembly of complex V, whereas complexes II and IV were normally active. This resulted in impaired oxygen consumption in cultured Pex5(-/-) hepatocytes. Second, mitochondrial DNA was depleted causing an imbalance in the expression of mitochondrial- and nuclear-encoded subunits of the respiratory chain complexes. Third, mitochondrial membranes showed increased permeability and fluidity despite reduced content of the polyunsaturated fatty acid docosahexaenoic acid. Fourth, the affected mitochondria in peroxisome deficient hepatocytes displayed increased oxidative stress. Acute deletion of PEX5 in vivo using adeno-Cre virus phenocopied these effects, indicating that mitochondrial perturbations closely follow the loss of functional peroxisomes in time. Likely to compensate for the functional impairments, the volume of the mitochondrial compartment was increased several folds. This was not driven by PGC-1α but mediated by activation of PPARα, possibly through c-myc overexpression. In conclusion, loss of peroxisomal metabolism in hepatocytes perturbs the mitochondrial inner membrane, depletes mitochondrial DNA and causes mitochondrial biogenesis independent of PGC-1α.
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32
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Individual exome analysis in diagnosis and management of paediatric liver failure of indeterminate aetiology. J Hepatol 2014; 61:1056-63. [PMID: 25016221 PMCID: PMC4203706 DOI: 10.1016/j.jhep.2014.06.038] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/20/2014] [Accepted: 06/30/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS In children with liver failure, as many as half remain of indeterminate aetiology. This hinders timely consideration of optimal treatment options. We posit that a significant subset of these children harbour known inherited metabolic liver diseases with atypical presentation or novel inborn errors of metabolism. We investigated the utility of whole-exome sequencing in three children with advanced liver disease of indeterminate aetiology. METHODS Patient 1 was a 10 year-old female diagnosed with Wilson disease but no detectable ATP7B mutations, and decompensated liver cirrhosis who underwent liver transplant and subsequently developed onset of neurodegenerative disease. Patient 2 was a full-term 2 day-old male with fatal acute liver failure of indeterminate aetiology. Patient 3 was an 8 year-old female with progressive syndromic cholestasis of unknown aetiology since age 3 months. RESULTS Unbiased whole-exome sequencing of germline DNA revealed homozygous mutations in MPV17 and SERAC1 as the disease causing genes in patient 1 and 2, respectively. This is the first demonstration of SERAC1 loss-of-function associated fatal acute liver failure. Patient 1 expands the phenotypic spectrum of the MPV17-related hepatocerebral mitochondrial DNA depletion syndrome. Patient 3 was found to have syndromic cholestasis due to bi-allelic NOTCH2 mutations. CONCLUSIONS Our findings validate the application of whole-exome sequencing in the diagnosis and management of children with advanced liver disease of indeterminate aetiology, with the potential to enhance optimal selection of treatment options and adequate counselling of families. Moreover, whole-exome sequencing revealed a hitherto unrecognized phenotypic spectrum of inherited metabolic liver diseases.
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Lumish HS, Yang Y, Xia F, Wilson A, Chung WK. The Expanding MEGDEL Phenotype: Optic Nerve Atrophy, Microcephaly, and Myoclonic Epilepsy in a Child with SERAC1 Mutations. JIMD Rep 2014; 16:75-9. [PMID: 24997715 PMCID: PMC4221303 DOI: 10.1007/8904_2014_322] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/03/2014] [Accepted: 05/20/2014] [Indexed: 01/30/2023] Open
Abstract
The inborn errors of metabolism associated with 3-methylglutaconic aciduria are a diverse group of disorders characterized by the excretion of 3-methylglutaconic and 3-methylglutaric acids in the urine. Mutations in several genes have been identified in association with 3-methylglutaconic aciduria. We describe a patient of Saudi Arabian descent with 3-methylglutaconic aciduria, sensorineural hearing loss, encephalopathy, and Leigh-like pattern on MRI (MEGDEL syndrome), as well as developmental delay and developmental regression, bilateral optic nerve atrophy, microcephaly, and myoclonic epilepsy. The patient had an earlier age of onset of optic atrophy than previously described in other MEGDEL syndrome patients. Whole exome sequencing revealed two loss-of-function mutations in SERAC1 in trans: c.438delC (p.T147Rfs*22) and c.442C>T (p.R148X), confirmed by Sanger sequencing. One of these mutations is novel (c.438delC). This case contributes to refining the MEGDEL phenotype.
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Affiliation(s)
- Heidi S. Lumish
- />College of Physicians and Surgeons, Columbia University, New York, NY USA
| | - Yaping Yang
- />Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX USA
| | - Fan Xia
- />Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX USA
| | - Ashley Wilson
- />Division of Clinical Genetics, New York Presbyterian Hospital, New York, NY USA
| | - Wendy K. Chung
- />Department of Pediatrics and Medicine, Columbia University, New York, NY USA
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Fukuoh A, Cannino G, Gerards M, Buckley S, Kazancioglu S, Scialo F, Lihavainen E, Ribeiro A, Dufour E, Jacobs HT. Screen for mitochondrial DNA copy number maintenance genes reveals essential role for ATP synthase. Mol Syst Biol 2014; 10:734. [PMID: 24952591 PMCID: PMC4265055 DOI: 10.15252/msb.20145117] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The machinery of mitochondrial DNA (mtDNA) maintenance is only partially characterized and is of wide interest due to its involvement in disease. To identify novel components of this machinery, plus other cellular pathways required for mtDNA viability, we implemented a genome-wide RNAi screen in Drosophila S2 cells, assaying for loss of fluorescence of mtDNA nucleoids stained with the DNA-intercalating agent PicoGreen. In addition to previously characterized components of the mtDNA replication and transcription machineries, positives included many proteins of the cytosolic proteasome and ribosome (but not the mitoribosome), three proteins involved in vesicle transport, some other factors involved in mitochondrial biogenesis or nuclear gene expression, > 30 mainly uncharacterized proteins and most subunits of ATP synthase (but no other OXPHOS complex). ATP synthase knockdown precipitated a burst of mitochondrial ROS production, followed by copy number depletion involving increased mitochondrial turnover, not dependent on the canonical autophagy machinery. Our findings will inform future studies of the apparatus and regulation of mtDNA maintenance, and the role of mitochondrial bioenergetics and signaling in modulating mtDNA copy number.
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Affiliation(s)
- Atsushi Fukuoh
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Graduate school of Medical Sciences, Fukuoka, Japan Department of Medical Laboratory Science, Junshin Gakuen University, Fukuoka, Japan
| | - Giuseppe Cannino
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Mike Gerards
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Suzanne Buckley
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Selena Kazancioglu
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Filippo Scialo
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Eero Lihavainen
- Department of Signal Processing, Tampere University of Technology, Tampere, Finland
| | - Andre Ribeiro
- Department of Signal Processing, Tampere University of Technology, Tampere, Finland
| | - Eric Dufour
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Howard T Jacobs
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland Research Program of Molecular Neurology, University of Helsinki, Helsinki, Finland
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The usefulness of whole-exome sequencing in routine clinical practice. Genet Med 2014; 16:922-31. [PMID: 24901346 DOI: 10.1038/gim.2014.58] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/23/2014] [Indexed: 01/06/2023] Open
Abstract
PURPOSE Reports of the use of whole-exome sequencing in clinical practice are limited. We report our experience with whole-exome sequencing in 115 patients in a single center and evaluate its feasibility and clinical usefulness in clinical care. METHODS Whole-exome sequencing was utilized based on the judgment of three clinical geneticists. We describe age, gender, ethnicity, consanguinity, indication for testing, family history, insurance, laboratory results, clinician interpretation of results, and impact on patient care. RESULTS Most patients were children (78.9%). The most common indications for testing were birth defects (24.3%) and developmental delay (25.2%). We identified four new candidate human disease genes and possibly expanded the disease phenotypes associated with five different genes. Establishing a diagnosis led to discontinuation of additional planned testing in all patients, screening for additional manifestations in eight, altered management in fourteen, novel therapy in two, identification of other familial mutation carriers in five, and reproductive planning in six. CONCLUSION Our results show that whole-exome sequencing is feasible, has clinical usefulness, and allows timely medical interventions, informed reproductive choices, and avoidance of additional testing. Our results also suggest phenotype expansion and identification of new candidate disease genes that would have been impossible to diagnose by other targeted testing methods.
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