1
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Yano N, Chong PF, Kojima KK, Miyoshi T, Luqmen-Fatah A, Kimura Y, Kora K, Kayaki T, Maizuru K, Hayashi T, Yokoyama A, Ajiro M, Hagiwara M, Kondo T, Kira R, Takita J, Yoshida T. Long-read sequencing identifies an SVA_D retrotransposon insertion deep within the intron of ATP7A as a novel cause of occipital horn syndrome. J Med Genet 2024:jmg-2024-110056. [PMID: 38960580 DOI: 10.1136/jmg-2024-110056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 06/25/2024] [Indexed: 07/05/2024]
Abstract
BACKGROUND SINE-VNTR-Alu (SVA) retrotransposons move from one genomic location to another in a 'copy-and-paste' manner. They continue to move actively and cause monogenic diseases through various mechanisms. Currently, disease-causing SVA retrotransposons are classified into human-specific young SVA_E or SVA_F subfamilies. In this study, we identified an evolutionarily old SVA_D retrotransposon as a novel cause of occipital horn syndrome (OHS). OHS is an X-linked, copper metabolism disorder caused by dysfunction of the copper transporter, ATP7A. METHODS We investigated a 16-year-old boy with OHS whose pathogenic variant could not be detected via routine molecular genetic analyses. RESULTS A 2.8 kb insertion was detected deep within the intron of the patient's ATP7A gene. This insertion caused aberrant mRNA splicing activated by a new donor splice site located within it. Long-read circular consensus sequencing enabled us to accurately read the entire insertion sequence, which contained highly repetitive and GC-rich segments. Consequently, the insertion was identified as an SVA_D retrotransposon. Antisense oligonucleotides (AOs) targeting the new splice site restored the expression of normal transcripts and functional ATP7A proteins. AO treatment alleviated excessive accumulation of copper in patient fibroblasts in a dose-dependent manner. Pedigree analysis revealed that the retrotransposon had moved into the OHS-causing position two generations ago. CONCLUSION This is the first report of a human monogenic disease caused by the SVA_D retrotransposon. The fact that the evolutionarily old SVA_D is still actively transposed, leading to increased copy numbers may make a notable impact on rare genetic disease research.
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Affiliation(s)
- Naoko Yano
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Pin Fee Chong
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kenji K Kojima
- Genetic Information Research Institute, Cupertino, CA, USA
| | - Tomoichiro Miyoshi
- Laboratory for Retrotransposon Dynamics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Department of Gene Mechanisms, Kyoto University Graduate School of Biostudies, Kyoto, Japan
| | - Ahmad Luqmen-Fatah
- Laboratory for Retrotransposon Dynamics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Yu Kimura
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Kengo Kora
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Taisei Kayaki
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kanako Maizuru
- Department of Pediatrics, Tenri Yorozu Hospital, Tenri, Japan
| | - Takahiro Hayashi
- Department of Pediatrics, Kurashiki Central Hospital, Kurashiki, Japan
| | - Atsushi Yokoyama
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masahiko Ajiro
- Division of Cancer RNA Research, National Cancer Center Research Institute, Tokyo, Japan
| | - Masatoshi Hagiwara
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Teruyuki Kondo
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Ryutaro Kira
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Junko Takita
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeshi Yoshida
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
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2
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Chu C, Lin EW, Tran A, Jin H, Ho NI, Veit A, Cortes-Ciriano I, Burns KH, Ting DT, Park PJ. The landscape of human SVA retrotransposons. Nucleic Acids Res 2023; 51:11453-11465. [PMID: 37823611 PMCID: PMC10681720 DOI: 10.1093/nar/gkad821] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 09/12/2023] [Accepted: 09/20/2023] [Indexed: 10/13/2023] Open
Abstract
SINE-VNTR-Alu (SVA) retrotransposons are evolutionarily young and still-active transposable elements (TEs) in the human genome. Several pathogenic SVA insertions have been identified that directly mutate host genes to cause neurodegenerative and other types of diseases. However, due to their sequence heterogeneity and complex structures as well as limitations in sequencing techniques and analysis, SVA insertions have been less well studied compared to other mobile element insertions. Here, we identified polymorphic SVA insertions from 3646 whole-genome sequencing (WGS) samples of >150 diverse populations and constructed a polymorphic SVA insertion reference catalog. Using 20 long-read samples, we also assembled reference and polymorphic SVA sequences and characterized the internal hexamer/variable-number-tandem-repeat (VNTR) expansions as well as differing SVA activity for SVA subfamilies and human populations. In addition, we developed a module to annotate both reference and polymorphic SVA copies. By characterizing the landscape of both reference and polymorphic SVA retrotransposons, our study enables more accurate genotyping of these elements and facilitate the discovery of pathogenic SVA insertions.
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Affiliation(s)
- Chong Chu
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Eric W Lin
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
- Department of Medicine, Massachusetts General Hospital Harvard Medical School, Boston, MA 02114, USA
| | - Antuan Tran
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Hu Jin
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Natalie I Ho
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
- Department of Medicine, Massachusetts General Hospital Harvard Medical School, Boston, MA 02114, USA
| | - Alexander Veit
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Isidro Cortes-Ciriano
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge, UK
| | - Kathleen H Burns
- Department of Pathology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - David T Ting
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
- Department of Medicine, Massachusetts General Hospital Harvard Medical School, Boston, MA 02114, USA
| | - Peter J Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
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3
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Fu X, Yang X, Wang X, Jia B, Ma W, Xiong H, Fang F, Ren X, Lv J. HyperCKemia: An early sign of childhood-onset neutral lipid storage disease with myopathy. Neuromuscul Disord 2023; 33:81-89. [PMID: 37620213 DOI: 10.1016/j.nmd.2023.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 08/26/2023]
Abstract
Neutral lipid-storage disease with myopathy (NLSDM) is an autosomal recessive neuromuscular disorder caused by mutations in PNPLA2, and the average age at onset is 30 years. To date, only eight patients with childhood-onset NLSDM have been reported in detail. We investigated 3 unreported patients with NLSDM detected in childhood and reviewed 8 childhood-onset and 82 adult-onset patients with NLSDM documented in the literature. In the childhood-onset cohort, NLSDM presented initially as asymptomatic or paucisymptomatic hyperCKemia in 6/11 patients, and follow-up data showed onset of muscle weakness in 6/11 childhood-onset patients. In the adult-onset cohort, 95.1% (78/82) of patients showed muscle weakness. Cardiac involvement developed in 6/11 childhood-onset patients. Hepatomegaly was observed in 3/11 childhood-onset patients. Serum creatine kinase levels were elevated greater than five-fold of the upper limit of normal (ULN) in most childhood-onset patients and were elevated to less than ten-fold of the ULN in most adult-onset patients. Peripheral blood smears and muscle biopsies showed cytoplasmic lipid droplets in leukocytes and myocytes. NLSDM can present in children with asymptomatic or paucisymptomatic hyperCKemia before the onset of muscle weakness. The presence of lipid droplets in leucocytes (Jordans' anomaly) aids in diagnosing and confirming the pathogenicity of PNPLA2 variants of uncertain significance. There were no clear genotype-phenotype correlations in patients with NLSDM.
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Affiliation(s)
- Xiaona Fu
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Xinying Yang
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Xiaofei Wang
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Bingbing Jia
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Wenna Ma
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Fang Fang
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Xiaotun Ren
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China.
| | - Junlan Lv
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China.
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4
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Effects of Triheptanoin on Mitochondrial Respiration and Glycolysis in Cultured Fibroblasts from Neutral Lipid Storage Disease Type M (NLSD-M) Patients. Biomolecules 2023; 13:biom13030452. [PMID: 36979387 PMCID: PMC10046759 DOI: 10.3390/biom13030452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
Neutral lipid storage disease type M (NLSD-M) is an ultra-rare, autosomal recessive disorder that causes severe skeletal and cardiac muscle damage and lipid accumulation in all body tissues. In this hereditary pathology, the defective action of the adipose triglyceride lipase (ATGL) enzyme induces the enlargement of cytoplasmic lipid droplets and reduction in the detachment of mono- (MG) and diglycerides (DG). Although the pathogenesis of muscle fiber necrosis is unknown, some studies have shown alterations in cellular energy production, probably because MG and DG, the substrates of Krebs cycle, are less available. No tests have been tried with medium-chain fatty acid molecules to evaluate the anaplerotic effect in NLSD cells. In this study, we evaluated the in vitro effect of triheptanoin (Dojolvi®), a highly purified chemical triglyceride with seven carbon atoms, in fibroblasts obtained from five NLSD-M patients. Glycolytic and mitochondrial functions were determined by Seahorse XF Agylent Technology, and cellular viability and triglyceride content were measured through colorimetric assays. After the addition of triheptanoin, we observed an increase in glycolysis and mitochondrial respiration in all patients compared with healthy controls. These preliminary results show that triheptanoin is able to induce an anaplerotic effect in NLSD-M fibroblasts, paving the way towards new therapeutic strategies.
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5
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Vezain M, Thauvin-Robinet C, Vial Y, Coutant S, Drunat S, Urtizberea JA, Rolland A, Jacquin-Piques A, Fehrenbach S, Nicolas G, Lecoquierre F, Saugier-Veber P. Retrotransposon insertion as a novel mutational cause of spinal muscular atrophy. Hum Genet 2023; 142:125-138. [PMID: 36138164 DOI: 10.1007/s00439-022-02473-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/15/2022] [Indexed: 01/18/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder resulting from biallelic alterations of the SMN1 gene: deletion, gene conversion or, in rare cases, intragenic variants. The disease severity is mainly influenced by the copy number of SMN2, a nearly identical gene, which produces only low amounts of full-length (FL) mRNA. Here we describe the first example of retrotransposon insertion as a pathogenic SMN1 mutational event. The 50-year-old patient is clinically affected by SMA type III with a diagnostic odyssey spanning nearly 30 years. Despite a mild disease course, he carries a single SMN2 copy. Using Exome Sequencing and Sanger sequencing, we characterized a SINE-VNTR-Alu (SVA) type F retrotransposon inserted in SMN1 intron 7. Using RT-PCR and RNASeq experiments on lymphoblastoid cell lines, we documented the dramatic decrease of FL transcript production in the patient compared to subjects with the same SMN1 and SMN2 copy number, thus validating the pathogenicity of this SVA insertion. We described the mutant FL-SMN1-SVA transcript characterized by exon extension and showed that it is subject to degradation by nonsense-mediated mRNA decay. The stability of the SMN-SVA protein may explain the mild course of the disease. This observation exemplifies the role of retrotransposons in human genetic disorders.
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Affiliation(s)
- Myriam Vezain
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France.,Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France
| | - Christel Thauvin-Robinet
- INSERM UMR1231 GAD-Génétique des Anomalies du Développement, Bourgogne Franche-Comté University, F-21000 , Dijon, France.,Genetics Center, Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, F-21000, Dijon, France
| | - Yoann Vial
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France.,Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France.,Genetics Department, AP-HP, Robert-Debré University Hospital, 48 boulevard Sérurier, 75019 , Paris, France
| | - Sophie Coutant
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France.,Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France
| | - Séverine Drunat
- INSERM UMR 1141, PROTECT, Paris University, F-75019, Paris, France.,Genetics Department, AP-HP, Robert-Debré University Hospital, F-75019, Paris, France
| | - Jon Andoni Urtizberea
- Myology Institute, AP-HP Pitié-Salpêtrière University Hospital, F-75013, Paris, France
| | - Anne Rolland
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France.,Pediatrics Department, Valence Hospital, 179 boulevard du Maréchal Juin, 26000, Valence, France
| | - Agnès Jacquin-Piques
- Department of Neurology, Clinical Neurophysiology, Competence Center of Neuromuscular Diseases, Dijon-Burgundy University Hospital, F-21000, Dijon, France
| | - Séverine Fehrenbach
- Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France
| | - Gaël Nicolas
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France.,Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France
| | - François Lecoquierre
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France.,Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France
| | - Pascale Saugier-Veber
- INSERM UMR1245, UNIROUEN, Normandie Univ, F-76000, Rouen, France. .,Department of Genetics, FHU G4 Génomique, Rouen University Hospital, F-76000, Rouen, France. .,Laboratoire de Génétique Moléculaire, UFR-Santé, 22 boulevard Gambetta, 76183, Rouen, France.
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6
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Missaglia S, Tavian D, Angelini C. Neutral lipid storage disease with myopathy: A 10-year follow-up case report. Eur J Transl Myol 2022. [PMID: 35713537 DOI: 10.4081/ejtm.2022.10645.pmid:35713537;pmcid:pmc9295162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Mutations in PNPLA2 gene encoding for adipose triglyceride lipase (ATGL), involved in triglyceride degradation, lead to an inborn error of neutral lipid metabolism. The disorder that results in abnormal storage of neutral lipid is known as neutral lipid storage disease with myopathy (NLSDM). We report the follow-up of a 30-year-old woman with NLSDM, asymptomatic until age 23. At the age of 18, a high level of CPK and neutral lipid abnormal accumulation in muscle and skin cells suggested NLSDM diagnosis, afterwards confirmed by PNPLA2 analysis. After 5 years, she developed weakness in the upper and lower extremities. She was put on a low-fat diet with medium-chain triglycerides (MCT) oil supplementation but, although her CPK level decreased, myopathy continued to progress. At present, she presents severe skeletal myopathy without cardiac involvement. In this patient, no beneficial effects on progressive skeletal muscle weakness were detected after the MCT diet, probably due to complete loss of PNPLA2 expression.
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Affiliation(s)
- Sara Missaglia
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Università Cattolica del Sacro Cuore, Milan, Italy; Department of Psychology, Università Cattolica del Sacro Cuore, Milan.
| | - Daniela Tavian
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Università Cattolica del Sacro Cuore, Milan, Italy; Department of Psychology, Università Cattolica del Sacro Cuore, Milan.
| | - Corrado Angelini
- Neuromuscular Laboratory, Department of Neurosciences, University of Padova, Campus Biomedico Pietro d'Abano, Padua.
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7
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Missaglia S, Tavian D, Angelini C. Neutral lipid storage disease with myopathy: A 10-year follow-up case report. Eur J Transl Myol 2022; 32. [PMID: 35713537 PMCID: PMC9295162 DOI: 10.4081/ejtm.2022.10645] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/11/2022] [Indexed: 11/25/2022] Open
Abstract
Mutations in PNPLA2 gene encoding for adipose triglyceride lipase (ATGL), involved in triglyceride degradation, lead to an inborn error of neutral lipid metabolism. The disorder that results in abnormal storage of neutral lipid is known as neutral lipid storage disease with myopathy (NLSDM). We report the follow-up of a 30-year-old woman with NLSDM, asymptomatic until age 23. At the age of 18, a high level of CPK and neutral lipid abnormal accumulation in muscle and skin cells suggested NLSDM diagnosis, afterwards confirmed by PNPLA2 analysis. After 5 years, she developed weakness in the upper and lower extremities. She was put on a low-fat diet with medium-chain triglycerides (MCT) oil supplementation but, although her CPK level decreased, myopathy continued to progress. At present, she presents severe skeletal myopathy without cardiac involvement. In this patient, no beneficial effects on progressive skeletal muscle weakness were detected after the MCT diet, probably due to complete loss of PNPLA2 expression.
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Affiliation(s)
- Sara Missaglia
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Università Cattolica del Sacro Cuore, Milan, Italy; Department of Psychology, Università Cattolica del Sacro Cuore, Milan.
| | - Daniela Tavian
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Università Cattolica del Sacro Cuore, Milan, Italy; Department of Psychology, Università Cattolica del Sacro Cuore, Milan.
| | - Corrado Angelini
- Neuromuscular Laboratory, Department of Neurosciences, University of Padova, Campus Biomedico Pietro d'Abano, Padua.
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8
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Pfaff AL, Singleton LM, Kõks S. Mechanisms of disease-associated SINE-VNTR-Alus. Exp Biol Med (Maywood) 2022; 247:756-764. [PMID: 35387528 DOI: 10.1177/15353702221082612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
SINE-VNTR-Alus (SVAs) are the youngest retrotransposon family in the human genome. Their ongoing mobilization has generated genetic variation within the human population. At least 24 insertions to date, detailed in this review, have been associated with disease. The predominant mechanisms through which this occurs are alterations to normal splicing patterns, exonic insertions causing loss-of-function mutations, and large genomic deletions. Dissecting the functional impact of these SVAs and the mechanism through which they cause disease provides insight into the consequences of their presence in the genome and how these elements could influence phenotypes. Many of these disease-associated SVAs have been difficult to characterize and would not have been identified through routine analyses. However, the number identified has increased in recent years as DNA and RNA sequencing data became more widely available. Therefore, as the search for complex structural variation in disease continues, it is likely to yield further disease-causing SVA insertions.
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Affiliation(s)
- Abigail L Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Lewis M Singleton
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
| | - Sulev Kõks
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
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9
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Tavian D, Maggi L, Mora M, Morandi L, Bragato C, Missaglia S. A novel PNPLA2 mutation causing total loss of RNA and protein expression in two NLSDM siblings with early onset but slowly progressive severe myopathy. Genes Dis 2021; 8:73-78. [PMID: 33569515 PMCID: PMC7859421 DOI: 10.1016/j.gendis.2019.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/12/2019] [Accepted: 07/22/2019] [Indexed: 12/21/2022] Open
Abstract
Neutral lipid storage disease with myopathy (NLSDM) is a rare autosomal recessive disorder, due to an enzymatic error of lipid metabolism. Patients present always with skeletal muscle myopathy and variable cardiac and hepatic involvement. NLSDM is caused by mutations in the PNPLA2 gene, which encodes the adipose triglyceride lipase (ATGL). Here we report the molecular characterization and clinical findings of two NLSDM siblings carrying the novel c.187+1G > C homozygous PNPLA2 mutation, localized in the splice site of intron 2. Molecular analyses revealed that neither aberrant PNPLA2 mRNA isoforms, nor ATGL mutated protein were detectable in patient's cells. Clinically, both patients presented early onset muscle weakness, in particular of proximal upper limb muscles. In almost 15 years, muscle damage affected also distal upper limbs. This is a NLSDM family, displaying a severe PNPLA2 mutation in two siblings with clinical presentation characterized by an early onset, but a slowly evolution of severe myopathy.
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Affiliation(s)
- Daniela Tavian
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Università Cattolica del Sacro Cuore, pz Buonarroti 30, Milan, 20145, Italy
- Department of Psychology, Università Cattolica del Sacro Cuore, Largo Gemelli 1, Milan, 20123, Italy
| | - Lorenzo Maggi
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Lucia Morandi
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Cinzia Bragato
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
- PhD program in Neuroscience, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Sara Missaglia
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Università Cattolica del Sacro Cuore, pz Buonarroti 30, Milan, 20145, Italy
- Department of Psychology, Università Cattolica del Sacro Cuore, Largo Gemelli 1, Milan, 20123, Italy
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10
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Early onset neutral lipid storage disease with myopathy presenting as congenital hypotonia and hepatomegaly. Neuromuscul Disord 2020; 31:52-55. [PMID: 33303358 DOI: 10.1016/j.nmd.2020.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/09/2020] [Accepted: 11/12/2020] [Indexed: 12/23/2022]
Abstract
Neutral lipid storage disease with myopathy is an ultra-rare, inherited autosomal recessive neuromuscular metabolic disorder caused by pathogenic variants in PNPLA2. It typically presents in adults as a progressive myopathy and is associated with myocardiopathy, hepatic involvement, and high creatine kinase levels. Only three children and adolescents with neutral lipid storage disease with myopathy have been reported. We report a female infant with congenital hypotonia born to consanguineous parents, whose mother presented with polyhydramnios during pregnancy. She demonstrated delayed acquisition of motor milestones, hepatomegaly, and elevated creatine kinase levels. Homozygous pathogenic variants in PNPLA2 were identified. Lipid accumulation was observed within the muscle fibers and Jordans' anomaly was observed in a blood smear. This is the first report to describe an infant with mildly symptomatic neutral lipid storage disease with myopathy and demonstrate hepatic involvement in a pediatric patient. Despite her mild symptoms, her ancillary test results were markedly abnormal.
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11
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Friend or Foe: Lipid Droplets as Organelles for Protein and Lipid Storage in Cellular Stress Response, Aging and Disease. Molecules 2020; 25:molecules25215053. [PMID: 33143278 PMCID: PMC7663626 DOI: 10.3390/molecules25215053] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 02/06/2023] Open
Abstract
Lipid droplets (LDs) were considered as a mere lipid storage organelle for a long time. Recent evidence suggests that LDs are in fact distinct and dynamic organelles with a specialized proteome and functions in many cellular roles. As such, LDs contribute to cellular signaling, protein and lipid homeostasis, metabolic diseases and inflammation. In line with the multitude of functions, LDs interact with many cellular organelles including mitochondria, peroxisomes, lysosomes, the endoplasmic reticulum and the nucleus. LDs are highly mobile and dynamic organelles and impaired motility disrupts the interaction with other organelles. The reduction of interorganelle contacts results in a multitude of pathophysiologies and frequently in neurodegenerative diseases. Contacts not only supply lipids for β-oxidation in mitochondria and peroxisomes, but also may include the transfer of toxic lipids as well as misfolded and harmful proteins to LDs. Furthermore, LDs assist in the removal of protein aggregates when severe proteotoxic stress overwhelms the proteasomal system. During imbalance of cellular lipid homeostasis, LDs also support cellular detoxification. Fine-tuning of LD function is of crucial importance and many diseases are associated with dysfunctional LDs. We summarize the current understanding of LDs and their interactions with organelles, providing a storage site for harmful proteins and lipids during cellular stress, aging inflammation and various disease states.
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12
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Zhang W, Wen B, Lu J, Zhao Y, Hong D, Zhao Z, Zhang C, Luo Y, Qi X, Zhang Y, Song X, Zhao Y, Zhao C, Hu J, Yang H, Wang Z, Yan C, Yuan Y. Neutral lipid storage disease with myopathy in China: a large multicentric cohort study. Orphanet J Rare Dis 2019; 14:234. [PMID: 31655616 PMCID: PMC6815004 DOI: 10.1186/s13023-019-1209-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 09/24/2019] [Indexed: 06/18/2023] Open
Abstract
Background Neutral lipid storage disease with myopathy (NLSDM) is a rare clinical heterogeneous disorder caused by mutations in the patatin-like phospholipase domain-containing 2 (PNPLA2) gene. NLSDM usually presents skeletal myopathy, cardiomyopathy and the multiple organs dysfunction. Around 50 cases of NLSDM have been described worldwide, whereas the comprehensive understanding of this disease are still limited. We therefore recruit NLSDM patients from 10 centers across China, summarize the clinical, muscle imaging, pathological and genetic features, and analyze the genotype-phenotype relationship. Results A total of 45 NLSDM patients (18 men and 27 women) were recruited from 40 unrelated families. Thirteen patients were born from consanguineous parents. The phenotypes were classified as asymptomatic hyperCKemia (2/45), pure skeletal myopathy (18/45), pure cardiomyopathy (4/45), and the combination of skeletal myopathy and cardiomyopathy (21/45). Right upper limb weakness was the early and prominent feature in 61.5% of patients. On muscle MRI, the long head of the biceps femoris, semimembranosus and adductor magnus on thighs, the soleus and medial head of the gastrocnemius on lower legs showed the most severe fatty infiltration. Thirty-three families were carrying homozygous mutations, while seven families were carrying compound heterozygous mutations. A total of 23 mutations were identified including 11 (47.8%) point mutations, eight (34.8%) deletions and four (17.4%) insertions. c.757 + 1G > T, c.245G > A and c.187 + 1G > A were the three most frequent mutations. Among four groups of phenotypes, significant differences were shown in disease onset (< 20 years versus ≥20 years old, p = 0.003) and muscle pathology (with rimmed vacuoles versus without rimmed vacuoles, p = 0.001). PNPLA2 mutational type or functional defects did not show great impact on phenotypes. Conclusion We outline the clinical and genetic spectrum in a large cohort of NLSDM patients. Selective muscle fatty infiltration on posterior compartment of legs are characteristic of NLSDM. Chinese patients present with distinctive and relative hotspot PNPLA2 mutations. The disease onset age and pathological appearance of rimmed vacuoles are proved to be related with the clinical manifestations. The phenotypes are not strongly influenced by genetic defects, suggesting the multiple environmental risk factors in the development of NLSDM.
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Affiliation(s)
- Wei Zhang
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, West District, Beijing, 100034, China
| | - Bing Wen
- Department of Neurology, Qilu Hospital of Shandong University, No. 107, West Wenhua Road, Jinan, 250012, Shandong, China
| | - Jun Lu
- Department of Neurology, Huashan Hospital of Fudan University, Shanghai, People's Republic of China
| | - Yawen Zhao
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, West District, Beijing, 100034, China
| | - Daojun Hong
- Department of Neurology, Peking University People's Hospital, Beijing, People's Republic of China
| | - Zhe Zhao
- Department of Neurology, the Third Hospital of Hebei Medical University, Shijiazhuang, Hebei province, People's Republic of China
| | - Cheng Zhang
- Department of Neurology, the First Affiliated Hospital of Sun yat-sen University, Guangzhou, Guangdong province, People's Republic of China
| | - Yuebei Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, People's Republic of China
| | - Xueliang Qi
- Department of Neurology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi province, People's Republic of China
| | - Yingshuang Zhang
- Department of Neurology, Third Hospital, Peking University, Beijing, People's Republic of China
| | - Xueqin Song
- Department of Neurology, the Second Hospital of Hebei Medical University, Shijiazhuang, Hebei province, People's Republic of China
| | - Yuying Zhao
- Department of Neurology, Qilu Hospital of Shandong University, No. 107, West Wenhua Road, Jinan, 250012, Shandong, China
| | - Chongbo Zhao
- Department of Neurology, Huashan Hospital of Fudan University, Shanghai, People's Republic of China
| | - Jing Hu
- Department of Neurology, the Third Hospital of Hebei Medical University, Shijiazhuang, Hebei province, People's Republic of China
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, People's Republic of China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, West District, Beijing, 100034, China
| | - Chuanzhu Yan
- Department of Neurology, Qilu Hospital of Shandong University, No. 107, West Wenhua Road, Jinan, 250012, Shandong, China.
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, No.8 Xishiku Street, West District, Beijing, 100034, China.
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Angelini C, Pennisi E, Missaglia S, Tavian D. Metabolic lipid muscle disorders: biomarkers and treatment. Ther Adv Neurol Disord 2019; 12:1756286419843359. [PMID: 31040882 PMCID: PMC6477769 DOI: 10.1177/1756286419843359] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 03/08/2019] [Indexed: 12/21/2022] Open
Abstract
Lipid storage myopathies (LSMs) are metabolic disorders of the utilization of fat in muscles due to several different defects. In this review, a molecular update of LSMs is presented and recent attempts of finding treatment options are discussed. The main topics discussed are: primary carnitine deficiency, riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency, neutral lipid storage disorders and carnitine palmitoyl transferase deficiency. The most frequent presentations and genetic abnormalities are summarized. We present their diagnosis utilizing biomedical and morphological biomarkers and possible therapeutic interventions. The treatment of these metabolic disorders is a subject of active translational research but appears, in some cases, still elusive.
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Affiliation(s)
- Corrado Angelini
- Fondazione Ospedale San Camillo IRCCS, Via Alberoni 70, Venezia 30126, Italia
| | - Elena Pennisi
- Division of Neurology, S Filippo Neri Hospital, Rome, Italy
| | - Sara Missaglia
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Catholic University of the Sacred Heart, Milan, Italy Psychology Department, Catholic University of the Sacred Heart, Milan, Italy
| | - Daniela Tavian
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Catholic University of the Sacred Heart, Milan, Italy Psychology Department, Catholic University of the Sacred Heart, Milan, Italy
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14
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Neutral Lipid Storage Diseases as Cellular Model to Study Lipid Droplet Function. Cells 2019; 8:cells8020187. [PMID: 30795549 PMCID: PMC6406896 DOI: 10.3390/cells8020187] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 01/10/2023] Open
Abstract
Neutral lipid storage disease with myopathy (NLSDM) and with ichthyosis (NLSDI) are rare autosomal recessive disorders caused by mutations in the PNPLA2 and in the ABHD5/CGI58 genes, respectively. These genes encode the adipose triglyceride lipase (ATGL) and α-β hydrolase domain 5 (ABHD5) proteins, which play key roles in the function of lipid droplets (LDs). LDs, the main cellular storage sites of triacylglycerols and sterol esters, are highly dynamic organelles. Indeed, LDs are critical for both lipid metabolism and energy homeostasis. Partial or total PNPLA2 or ABHD5/CGI58 knockdown is characteristic of the cells of NLSD patients; thus, these cells are natural models with which one can unravel LD function. In this review we firstly summarize genetic and clinical data collected from NLSD patients, focusing particularly on muscle, skin, heart, and liver damage due to impaired LD function. Then, we discuss how NLSD cells were used to investigate and expand the current structural and functional knowledge of LDs.
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15
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Zhou K, Yao P, He J, Zhao H. Lipophagy in nonliver tissues and some related diseases: Pathogenic and therapeutic implications. J Cell Physiol 2018; 234:7938-7947. [PMID: 30537019 DOI: 10.1002/jcp.27988] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 11/21/2018] [Indexed: 12/24/2022]
Abstract
Lipid autophagy (lipophagy) is defined as a selective autophagy process in which some intracellular lipid droplets are selectively degraded by autophagic lysosomes pathway. The occurrence of lipophagy was first discovered in liver tissues. Additionally, abundant evidence indicated that the occurrence of hepatic lipophagy has been implicated in many liver diseases including fatty liver diseases, nonalcoholic fatty liver diseases, liver fibrosis, and liver cirrhosis. However, recent studies suggested that hepatic lipophagy occurs not only in liver tissue but also in other nonliver tissues and cells. Furthermore, the occurrence of lipophagy plays a crucial role in nonliver tissues and some related diseases. For instance, lipophagy relieves insulin resistance in adipose tissue from obesity patient with type 2 diabetes. Additionally, lipophagy has the ability to remit neurodegenerative diseases by reducing activity-dependent neurodegeneration in nervous tissue. Lipophagy decreases muscle lipid accumulation and accordingly improves lipid storage myopathy in muscle tissue. Moreover, lipophagy alleviates the malignancy and metastasis of cancer in clear renal cell carcinoma tissue. Lipophagy is also involved in other processes, such as spermatogenesis, osteoblastogenesis, and mucosal ulceration. In conclusion, targeting lipophagy may be a critical regulator and a new therapeutic strategy for nonliver tissues and some related diseases.
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Affiliation(s)
- Kebing Zhou
- Department of Emergency Medicine, Affiliated Nanhua Hospital, University of South China, Hengyang, China
| | - Pingbo Yao
- Department of Emergency Medicine, Affiliated Nanhua Hospital, University of South China, Hengyang, China
| | - Jun He
- Department of Emergency Medicine, Affiliated Nanhua Hospital, University of South China, Hengyang, China
| | - Hong Zhao
- Department of Basic nursing, Nursing College, University of South China, Hengyang, China
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16
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Garcia MA, Rojas JA, Millán SP, Flórez AA. Neutral lipid storage disease with myopathy and dropped head syndrome. Report of a new variant susceptible of treatment with late diagnosis. J Clin Neurosci 2018; 58:207-209. [DOI: 10.1016/j.jocn.2018.10.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 10/07/2018] [Indexed: 10/28/2022]
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17
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Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
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Disease onset in X-linked dystonia-parkinsonism correlates with expansion of a hexameric repeat within an SVA retrotransposon in TAF1. Proc Natl Acad Sci U S A 2017; 114:E11020-E11028. [PMID: 29229810 PMCID: PMC5754783 DOI: 10.1073/pnas.1712526114] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The genetic basis of X-Linked dystonia-parkinsonism (XDP) has been difficult to unravel, in part because all patients inherit the same haplotype of seven sequence variants, none of which has ever been identified in control individuals. This study revealed that one of the haplotype markers, a retrotransposon insertion within an intron of TAF1, has a variable number of hexameric repeats among affected individuals with an increase in repeat number strongly correlated with earlier age at disease onset. These data support a contributing role for this sequence in disease pathogenesis while further suggesting that XDP may be part of a growing list of neurodegenerative disorders associated with unstable repeat expansions. X-linked dystonia-parkinsonism (XDP) is a neurodegenerative disease associated with an antisense insertion of a SINE-VNTR-Alu (SVA)-type retrotransposon within an intron of TAF1. This unique insertion coincides with six additional noncoding sequence changes in TAF1, the gene that encodes TATA-binding protein–associated factor-1, which appear to be inherited together as an identical haplotype in all reported cases. Here we examined the sequence of this SVA in XDP patients (n = 140) and detected polymorphic variation in the length of a hexanucleotide repeat domain, (CCCTCT)n. The number of repeats in these cases ranged from 35 to 52 and showed a highly significant inverse correlation with age at disease onset. Because other SVAs exhibit intrinsic promoter activity that depends in part on the hexameric domain, we assayed the transcriptional regulatory effects of varying hexameric lengths found in the unique XDP SVA retrotransposon using luciferase reporter constructs. When inserted sense or antisense to the luciferase reading frame, the XDP variants repressed or enhanced transcription, respectively, to an extent that appeared to vary with length of the hexamer. Further in silico analysis of this SVA sequence revealed multiple motifs predicted to form G-quadruplexes, with the greatest potential detected for the hexameric repeat domain. These data directly link sequence variation within the XDP-specific SVA sequence to phenotypic variability in clinical disease manifestation and provide insight into potential mechanisms by which this intronic retroelement may induce transcriptional interference in TAF1 expression.
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19
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Pennisi EM, Arca M, Bertini E, Bruno C, Cassandrini D, D'amico A, Garibaldi M, Gragnani F, Maggi L, Massa R, Missaglia S, Morandi L, Musumeci O, Pegoraro E, Rastelli E, Santorelli FM, Tasca E, Tavian D, Toscano A, Angelini C. Neutral Lipid Storage Diseases: clinical/genetic features and natural history in a large cohort of Italian patients. Orphanet J Rare Dis 2017; 12:90. [PMID: 28499397 PMCID: PMC5427600 DOI: 10.1186/s13023-017-0646-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 05/03/2017] [Indexed: 12/20/2022] Open
Abstract
Background A small number of patients affected by Neutral Lipid Storage Diseases (NLSDs: NLSD type M with Myopathy and NLSD type I with Ichthyosis) have been described in various ethnic groups worldwide. However, relatively little is known about the progression and phenotypic variability of the disease in large specific populations. The aim of our study was to assess the natural history, disability and genotype-phenotype correlations in Italian patients with NLSDs. Twenty-one patients who satisfied the criteria for NLSDs were enrolled in a retrospective cross-sectional study to evaluate the genetic aspects, clinical signs at onset, disability progression and comorbidities associated with this group of diseases. Results During the clinical follow-up (range: 2–44 years, median: 17.8 years), two patients (9.5%, both with NLSD-I) died of hepatic failure, and a further five (24%) lost their ability to walk or needed help when walking after a mean period of 30.6 years of disease. None of the patients required mechanical ventilation. No patient required a heart transplant, one patient with NLSD-M was implanted with a cardioverter defibrillator for severe arrhythmias. Conclusion The genotype/phenotype correlation analysis in our population showed that the same gene mutations were associated with a varying clinical onset and course. This study highlights peculiar aspects of Italian NLSD patients that differ from those observed in Japanese patients, who were found to be affected by a marked hypertrophic cardiopathy. Owing to the varying phenotypic expression of the same mutations, it is conceivable that some additional genetic or epigenetic factors affect the symptoms and progression in this group of diseases.
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Affiliation(s)
- Elena Maria Pennisi
- UOC of Neurology, San Filippo Neri Hospital, via Martinotti 20, 00135, Rome, Italy.
| | - Marcello Arca
- Department of Internal Medicine and Allied Sciences, Atherosclerosis Unit, Sapienza University of Rome, Rome, Italy
| | | | | | | | | | | | | | - Lorenzo Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, Foundation IRCCS Neurological Institute "Carlo Besta", Milan, Italy
| | - Roberto Massa
- Department of Systems Medicine, Centre of Neuromuscular Disorders, Tor Vergata University, Rome, Italy
| | - Sara Missaglia
- CRIBENS, Catholic University of the Sacred Heart, Milan, Italy
| | - Lucia Morandi
- Neuroimmunology and Neuromuscular Diseases Unit, Foundation IRCCS Neurological Institute "Carlo Besta", Milan, Italy
| | - Olimpia Musumeci
- Department of Neurosciences, University of Messina, Messina, Italy
| | - Elena Pegoraro
- Department of Neurology, University of Padova, Padova, Italy
| | - Emanuele Rastelli
- Department of Systems Medicine, Centre of Neuromuscular Disorders, Tor Vergata University, Rome, Italy
| | | | | | - Daniela Tavian
- CRIBENS, Catholic University of the Sacred Heart, Milan, Italy
| | - Antonio Toscano
- Department of Neurosciences, University of Messina, Messina, Italy
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20
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Tavian D, Missaglia S, Castagnetta M, Degiorgio D, Pennisi EM, Coleman RA, Dell'Era P, Mora C, Angelini C, Coviello DA. Generation of induced Pluripotent Stem Cells as disease modelling of NLSDM. Mol Genet Metab 2017; 121:28-34. [PMID: 28391974 PMCID: PMC5434246 DOI: 10.1016/j.ymgme.2017.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 01/10/2023]
Abstract
Neutral Lipid Storage Disease with Myopathy (NLSDM) is a rare defect of triacylglycerol metabolism, characterized by the abnormal storage of neutral lipid in organelles known as lipid droplets (LDs). The main clinical features are progressive myopathy and cardiomyopathy. The onset of NLSDM is caused by autosomal recessive mutations in the PNPLA2 gene, which encodes adipose triglyceride lipase (ATGL). Despite its name, this enzyme is present in a wide variety of cell types and catalyzes the first step in triacylglycerol lipolysis and the release of fatty acids. Here, we report the derivation of NLSDM-induced pluripotent stem cells (NLSDM-iPSCs) from fibroblasts of two patients carrying different PNPLA2 mutations. The first patient was homozygous for the c.541delAC, while the second was homozygous for the c.662G>C mutation in the PNPLA2 gene. We verified that the two types of NLSDM-iPSCs possessed properties of embryonic-like stem cells and could differentiate into the three germ layers in vitro. Immunofluorescence analysis revealed that iPSCs had an abnormal accumulation of triglycerides in LDs, the hallmark of NLSDM. Furthermore, NLSDM-iPSCs were deficient in long chain fatty acid lipolysis, when subjected to a pulse chase experiment with oleic acid. Collectively, these results demonstrate that NLSDM-iPSCs are a promising in vitro model to investigate disease mechanisms and screen drug compounds for NLSDM, a rare disease with few therapeutic options.
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Affiliation(s)
- D Tavian
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Catholic University of the Sacred Heart, pz Buonarroti 30, Milan 20145, Italy; Psychology Department, Catholic University of the Sacred Heart, Largo Gemelli 1, Milan 20123, Italy.
| | - S Missaglia
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Catholic University of the Sacred Heart, pz Buonarroti 30, Milan 20145, Italy; Psychology Department, Catholic University of the Sacred Heart, Largo Gemelli 1, Milan 20123, Italy
| | - M Castagnetta
- Laboratory of Human Genetics, E.O. Ospedali Galliera, Via Volta 6, Genoa 16128, Italy
| | - D Degiorgio
- Laboratory of Human Genetics, E.O. Ospedali Galliera, Via Volta 6, Genoa 16128, Italy; Stem Cell Laboratory, Department of Experimental Medicine, University of Genoa, c/o Advanced Biotechnology Center, L.go R. Benzi, 10, Genoa 16132, Italy
| | - E M Pennisi
- UOC Neurologia, San Filippo Neri Hospital, via Martinotti 20, Rome 00135, Italy
| | - R A Coleman
- Department of Nutrition, University of North Carolina, Chapel Hill, NC 27599, USA
| | - P Dell'Era
- Cellular Fate Reprogramming Unit, Department of Molecular and Translational Medicine, University of Brescia, Brescia 25123, Italy
| | - C Mora
- Cellular Fate Reprogramming Unit, Department of Molecular and Translational Medicine, University of Brescia, Brescia 25123, Italy
| | - C Angelini
- IRCCS Fondazione Ospedale S. Camillo, Venice, Italy
| | - D A Coviello
- Laboratory of Human Genetics, E.O. Ospedali Galliera, Via Volta 6, Genoa 16128, Italy
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Hancks DC, Kazazian HH. Roles for retrotransposon insertions in human disease. Mob DNA 2016; 7:9. [PMID: 27158268 PMCID: PMC4859970 DOI: 10.1186/s13100-016-0065-9] [Citation(s) in RCA: 421] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/14/2016] [Indexed: 12/12/2022] Open
Abstract
Over evolutionary time, the dynamic nature of a genome is driven, in part, by the activity of transposable elements (TE) such as retrotransposons. On a shorter time scale it has been established that new TE insertions can result in single-gene disease in an individual. In humans, the non-LTR retrotransposon Long INterspersed Element-1 (LINE-1 or L1) is the only active autonomous TE. In addition to mobilizing its own RNA to new genomic locations via a "copy-and-paste" mechanism, LINE-1 is able to retrotranspose other RNAs including Alu, SVA, and occasionally cellular RNAs. To date in humans, 124 LINE-1-mediated insertions which result in genetic diseases have been reported. Disease causing LINE-1 insertions have provided a wealth of insight and the foundation for valuable tools to study these genomic parasites. In this review, we provide an overview of LINE-1 biology followed by highlights from new reports of LINE-1-mediated genetic disease in humans.
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Affiliation(s)
- Dustin C. Hancks
- />Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT USA
| | - Haig H. Kazazian
- />McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins School of Medicine, Baltimore, MD USA
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Massa R, Pozzessere S, Rastelli E, Serra L, Terracciano C, Gibellini M, Bozzali M, Arca M. Neutral lipid-storage disease with myopathy and extended phenotype with novel PNPLA2 mutation. Muscle Nerve 2016; 53:644-8. [PMID: 26600210 DOI: 10.1002/mus.24983] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2015] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Neutral lipid-storage disease with myopathy is caused by mutations in PNPLA2, which produce skeletal and cardiac myopathy. We report a man with multiorgan neutral lipid storage and unusual multisystem clinical involvement, including cognitive impairment. METHODS Quantitative brain MRI with voxel-based morphometry and extended neuropsychological assessment were performed. In parallel, the coding sequences and intron/exon boundaries of the PNPLA2 gene were screened by direct sequencing. RESULTS Neuropsychological assessment revealed global cognitive impairment, and brain MRI showed reduced gray matter volume in the temporal lobes. Molecular characterization revealed a novel homozygous mutation in exon 5 of PNPLA2 (c.714C>A), resulting in a premature stop codon (p.Cys238*). CONCLUSIONS Some PNPLA2 mutations, such as the one described here, may present with an extended phenotype, including brain involvement. In these cases, complete neuropsychological testing, combined with quantitative brain MRI, may help to characterize and quantify cognitive impairment.
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Affiliation(s)
- Roberto Massa
- Department of Systems Medicine (Neurology), University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy
| | - Simone Pozzessere
- Dipartimento di Medicina Interna e Specialità Mediche, Sapienza Università di Roma, Rome, Italy
| | - Emanuele Rastelli
- Department of Systems Medicine (Neurology), University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy
| | - Laura Serra
- Neuroimaging Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Chiara Terracciano
- Department of Systems Medicine (Neurology), University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy
| | - Manuela Gibellini
- Department of Systems Medicine (Neurology), University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy
| | - Marco Bozzali
- Neuroimaging Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Marcello Arca
- Dipartimento di Medicina Interna e Specialità Mediche, Sapienza Università di Roma, Rome, Italy
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Missaglia S, Tasca E, Angelini C, Moro L, Tavian D. Novel missense mutations in PNPLA2 causing late onset and clinical heterogeneity of neutral lipid storage disease with myopathy in three siblings. Mol Genet Metab 2015; 115:110-7. [PMID: 25956450 DOI: 10.1016/j.ymgme.2015.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 05/01/2015] [Indexed: 12/18/2022]
Abstract
Neutral lipid storage disease with myopathy (NLSD-M) is a rare autosomal recessive disorder characterised by an abnormal accumulation of triacylglycerol into cytoplasmic lipid droplets (LDs). NLSD-M patients are mainly affected by progressive myopathy, cardiomyopathy and hepatomegaly. Mutations in the PNPLA2 gene cause variable phenotypes of NLSD-M. PNPLA2 codes for adipose triglyceride lipase (ATGL), an enzyme that hydrolyses fatty acids from triacylglycerol. This report outlines the clinical and genetic findings in a NLSD-M Italian family with three affected members. In our patients, we identified two novel PNPLA2 missense mutations (p.L56R and p.I193F). Functional data analysis demonstrated that these mutations caused the production of ATGL proteins able to bind to LDs, but with decreased lipase activity. The oldest brother, at the age of 38, had weakness and atrophy of the right upper arm and kyphosis. Now he is 61 years old and is unable to raise arms in the horizontal position. The second brother, from the age of 44, had exercise intolerance, cramps and pain in lower limbs. He is currently 50 years old and has an asymmetric distal amyotrophy. One of the two sisters, 58 years old, presents the same PNPLA2 mutations, but she is still oligo-symptomatic on neuromuscular examination with slight triceps muscle involvement. She suffered from diabetes and liver steatosis. This NLSD-M family shows a wide range of intra-familial phenotypic variability in subjects carrying the same mutations, both in terms of target-organs and in terms of rate of disease progression.
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Affiliation(s)
- Sara Missaglia
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Catholic University of the Sacred Heart, Milan, Italy
| | | | | | - Laura Moro
- Department of Pharmaceutical Sciences, University of Piemonte Orientale "A. Avogadro", Novara, Italy
| | - Daniela Tavian
- Laboratory of Cellular Biochemistry and Molecular Biology, CRIBENS, Catholic University of the Sacred Heart, Milan, Italy; Psychology Department, Catholic University of the Sacred Heart, Milan, Italy.
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Pennisi EM, Missaglia S, Dimauro S, Bernardi C, Akman HO, Tavian D. A myopathy with unusual features caused by PNPLA2 gene mutations. Muscle Nerve 2015; 51:609-13. [PMID: 25287355 DOI: 10.1002/mus.24477] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2014] [Indexed: 12/19/2022]
Abstract
INTRODUCTION The PNPLA2 gene encodes the enzyme adipose triglyceride lipase (ATGL), which catalyzes the first step of triglyceride hydrolysis. Mutations in this gene are associated with an autosomal recessive lipid-storage myopathy, neutral lipid-storage disease with myopathy (NLSD-M). RESULTS A 72-year-old woman had late-onset myopathy, with mild weakness, cramps, and exercise intolerance. Electromyography showed myotonic discharges. A few leukocytes showed lipid droplets (Jordan anomaly). Deltoid and quadriceps muscle biopsies showed no lipid storage. Genetic analysis of PNPLA2 detected 2 heterozygous mutations: c.497A>G (p.Asp166Gly) in exon 5 and c.1442C>T (p.Pro481Leu) in exon 10. Expression of mutant PNPLA2 plasmids in HeLa cells resulted in impaired enzyme activity, confirming the pathological effects of the mutations. CONCLUSIONS In this case of NLSD-M, the myopathy may be due to a metabolic defect rather than to a mechanical effect of lipid storage. This suggests that more than 1 mechanism contributes to muscle damage in NLSD-M.
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Affiliation(s)
- Elena M Pennisi
- Division of Neurology, San Filippo Neri Hospital, Rome, Italy
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Kaneko K, Kuroda H, Izumi R, Tateyama M, Kato M, Sugimura K, Sakata Y, Ikeda Y, Hirano KI, Aoki M. A novel mutation in PNPLA2 causes neutral lipid storage disease with myopathy and triglyceride deposit cardiomyovasculopathy: A case report and literature review. Neuromuscul Disord 2014; 24:634-41. [DOI: 10.1016/j.nmd.2014.04.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/05/2014] [Accepted: 04/09/2014] [Indexed: 12/18/2022]
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Suzuki A, Nagasaka H, Ochi Y, Kobayashi K, Nakamura H, Nakatani D, Yamaguchi S, Yamaki S, Wada A, Shirata Y, Hui SP, Toda T, Kuroda H, Chiba H, Hirano KI. Peripheral leukocyte anomaly detected with routine automated hematology analyzer sensitive to adipose triglyceride lipase deficiency manifesting neutral lipid storage disease with myopathy/triglyceride deposit cardiomyovasculopathy. Mol Genet Metab Rep 2014; 1:249-253. [PMID: 27896096 PMCID: PMC5121313 DOI: 10.1016/j.ymgmr.2014.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 05/05/2014] [Accepted: 05/05/2014] [Indexed: 01/10/2023] Open
Abstract
Adipose triglyceride lipase (ATGL) deficiency manifesting neutral lipid storage disease with myopathy/triglyceride deposit cardiomyovasculopathy presents distinct fat-containing vacuoles known as Jordans' anomaly in peripheral leucocytes. To develop an automatic notification system for Jordans' anomaly in ATGL-deficient patients, we analyzed circulatory leukocyte scattergrams on automated hematology analyzer XE-5000. The BASO-WX and BASO-WY values were found to be significantly higher in patients than those in non-affected subjects. The two parameters measured by automated hematology analyzer may be expected to provide an important diagnostic clue for homozygous ATGL deficiency.
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Affiliation(s)
- Akira Suzuki
- Laboratory of Cardiovascular Disease, Novel, Non-invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, Suita, Osaka 565-0874, Japan
| | - Hironori Nagasaka
- Department of Pediatrics, Takarazuka City Hospital, Takarazuka 665-0827, Japan
| | - Yasuhiro Ochi
- Scientific Affairs, Sysmex Corporation, Kobe 651-2241, Japan
| | - Kazuhiro Kobayashi
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hiroshi Nakamura
- Department of Community Health and Medicine, Yamaguchi University, School of Medicine, Ube 755-8505, Japan
| | - Daisaku Nakatani
- Laboratory of Cardiovascular Disease, Novel, Non-invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, Suita, Osaka 565-0874, Japan
| | - Satoshi Yamaguchi
- Laboratory of Cardiovascular Disease, Novel, Non-invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, Suita, Osaka 565-0874, Japan
| | - Shinobu Yamaki
- Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Atsushi Wada
- Scientific Affairs, Sysmex Corporation, Kobe 651-2241, Japan
| | | | - Shu-Ping Hui
- Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tatsushi Toda
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hiroshi Kuroda
- Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
| | - Hitoshi Chiba
- Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Ken-Ichi Hirano
- Laboratory of Cardiovascular Disease, Novel, Non-invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, Suita, Osaka 565-0874, Japan
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Perrin L, Féasson L, Furby A, Laforêt P, Petit FM, Gautheron V, Chabrier S. PNPLA2 mutation: A paediatric case with early onset but indolent course. Neuromuscul Disord 2013; 23:986-91. [DOI: 10.1016/j.nmd.2013.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 07/30/2013] [Accepted: 08/19/2013] [Indexed: 12/16/2022]
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Kwon YJ, Choi Y, Eo J, Noh YN, Gim JA, Jung YD, Lee JR, Kim HS. Structure and Expression Analyses of SVA Elements in Relation to Functional Genes. Genomics Inform 2013; 11:142-8. [PMID: 24124410 PMCID: PMC3794087 DOI: 10.5808/gi.2013.11.3.142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/20/2013] [Accepted: 08/21/2013] [Indexed: 02/06/2023] Open
Abstract
SINE-VNTR-Alu (SVA) elements are present in hominoid primates and are divided into 6 subfamilies (SVA-A to SVA-F) and active in the human population. Using a bioinformatic tool, 22 SVA element-associated genes are identified in the human genome. In an analysis of genomic structure, SVA elements are detected in the 5' untranslated region (UTR) of HGSNAT (SVA-B), MRGPRX3 (SVA-D), HYAL1 (SVA-F), TCHH (SVA-F), and ATXN2L (SVA-F) genes, while some elements are observed in the 3'UTR of SPICE1 (SVA-B), TDRKH (SVA-C), GOSR1 (SVA-D), BBS5 (SVA-D), NEK5 (SVA-D), ABHD2 (SVA-F), C1QTNF7 (SVA-F), ORC6L (SVA-F), TMEM69 (SVA-F), and CCDC137 (SVA-F) genes. They could contribute to exon extension or supplying poly A signals. LEPR (SVA-C), ALOX5 (SVA-D), PDS5B (SVA-D), and ABCA10 (SVA-F) genes also showed alternative transcripts by SVA exonization events. Dominant expression of HYAL1_SVA appeared in lung tissues, while HYAL1_noSVA showed ubiquitous expression in various human tissues. Expression of both transcripts (TDRKH_SVA and TDRKH_noSVA) of the TDRKH gene appeared to be ubiquitous. Taken together, these data suggest that SVA elements cause transcript isoforms that contribute to modulation of gene regulation in various human tissues.
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Affiliation(s)
- Yun-Jeong Kwon
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Korea
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Laforêt P, Stojkovic T, Bassez G, Carlier PG, Clément K, Wahbi K, Petit FM, Eymard B, Carlier RY. Neutral lipid storage disease with myopathy: a whole-body nuclear MRI and metabolic study. Mol Genet Metab 2013; 108:125-31. [PMID: 23333026 DOI: 10.1016/j.ymgme.2012.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 10/27/2022]
Abstract
Neutral lipid storage disease with myopathy (NLSDM) is caused by a mutation in the gene encoding adipose triglyceride lipase (ATGL), and is characterized by the presence of numerous triglyceride-containing cytoplasmic droplets in type I muscle fibers. Major clinical manifestations concern the heart and skeletal muscle, and some patients also present diabetes mellitus. We report the clinical, metabolic, and whole-body nuclear magnetic resonance imaging findings of three patients with NLSDM. Muscle MRI study was consistent with previous descriptions, and allowed to show a common pattern of fatty replacement. Muscle changes predominated in the paravertebral muscles, both compartments of legs, and posterior compartment of the thighs. A more variable distribution of muscle involvement was observed on upper limbs, with marked asymmetry in one patient, and alterations predominating on supra and infra spinatus, biceps brachialis and anterior compartment of arms. Cardiac NMR studies revealed anomalies despite normal echocardiography in two patients. Endocrine studies showed low leptin and adiponectine levels, a moderate increase in insulin levels at fasting state, and even greater increase after oral glucose tolerance test in one patient. Two patients had elevated triglycerides and low cholesterol-HDL. Based on these analyses, regular control of cardiometabolic risks appear mandatory in the clinical follow-up of these subjects.
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Affiliation(s)
- Pascal Laforêt
- AP-HP, Centre de Référence de pathologie neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
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30
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Retroelements in human disease. Gene 2013; 518:231-41. [PMID: 23333607 DOI: 10.1016/j.gene.2013.01.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 12/28/2012] [Accepted: 01/02/2013] [Indexed: 12/16/2022]
Abstract
Retroelements are an abundant class of noncoding DNAs present in about half of the human genome. Among them, L1, Alu and SVA are currently active. They "jump" by retrotransposition, shuffle genomic regions by 5' and 3' transduction, and promote or inhibit gene transcription by providing alternative promoters or generating antisense and/or regulatory noncoding RNAs. Recent data also suggest that retroelement insertions into exons and introns of genes induce different types of genetic disease, including cancer. Retroelements interfere with the expression of genes by inducing alternative splicing via exon skipping and exonization using cryptic splice sites, and by providing polyadenylation signals. Here we summarize our current understanding of the molecular mechanisms of retroelement-induced mutagenesis which causes fifty different types of human disease. We categorize these mutagenic effects according to eleven different mechanisms and show that most of them may be explained either by traditional exon definition or transcriptional interference, a previously unrecognized molecular mechanism. In summary, this review gives an overview of retroelement insertions in genes that cause significant changes in their transcription and cotranscriptional splicing and show a remarkable level of complexity.
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31
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Subclinical myopathy in a child with neutral lipid storage disease and mutations in the PNPLA2 gene. Biochem Biophys Res Commun 2013; 430:241-4. [DOI: 10.1016/j.bbrc.2012.10.127] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 10/29/2012] [Indexed: 11/17/2022]
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Symptomatic lipid storage in carriers for the PNPLA2 gene. Eur J Hum Genet 2012; 21:807-15. [PMID: 23232698 DOI: 10.1038/ejhg.2012.256] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 10/12/2012] [Accepted: 10/26/2012] [Indexed: 01/25/2023] Open
Abstract
Neutral lipid storage disease comprises a heterogeneous group of inherited disorders characterized by severe accumulation of cytoplasmic triglyceride droplets in several tissues and neutrophils. A novel type of autosomal recessive lipid myopathy due to PNPLA2 mutations was recently described with associated cardiac disease, myopathy and frequent infections, but without ichthyosis. Here we describe the clinical and biochemical characteristics of a long surviving patient and report on four carrier family members with diverse clinical involvement. Interestingly, heterozygous patients show neutral lipid storage in muscle and in the keratocytes of the skin, Jordans' bodies, mild myopathy and frequent infections. Biochemical analysis of fibroblasts obtained from patients revealed increased triglyceride storage and reduced lipid droplet-associated triglyceride hydrolase activity. Together, our data implicate that the wild-type allele cannot fully compensate for the mutated dysfunctional allele of PNPLA2 leading to triglyceride accumulation in muscle and mild myopathy in PNPLA2 mutation carriers. The presence of neutral lipid droplets in the skin in PNPLA2 mutation carriers strengthens the link between NLSD and other neutral lipid storage diseases with ichthyosis.
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Ash DB, Papadimitriou D, Hays AP, Dimauro S, Hirano M. A novel mutation in PNPLA2 leading to neutral lipid storage disease with myopathy. ACTA ACUST UNITED AC 2012; 69:1190-2. [PMID: 22964912 DOI: 10.1001/archneurol.2011.2600] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Mutations in PNPLA2, a gene encoding adipose triglyceride lipase, lead to neutral lipid storage disease with myopathy. OBJECTIVE To report the clinical and molecular features of a case of neutral lipid storage disease with myopathy resulting from a novel mutation in PNPLA2. DESIGN Case report. SETTING University hospital. PATIENT A 65-year-old man with progressive muscle weakness and high serum creatine kinase levels. INTERVENTION Direct sequencing of the PNPLA2 gene. RESULTS Identification of a novel homozygous mutation in the patient's PNPLA2 gene confirmed the suspected diagnosis of neutral lipid storage disease with myopathy. CONCLUSION Screening of the PNPLA2 gene should be considered for patients presenting with high levels of creatine kinase, progressive muscle weakness, and systemic lipid accumulation. The presence of Jordans anomaly can be a strong diagnostic clue.
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Affiliation(s)
- Daniel B Ash
- Department ofNeurology, H. Houston Merritt Clinical Research Center, Columbia University Medical Center, 630W168th St,P&S 4-423, New York, NY 10032, USA.
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Tavian D, Missaglia S, Redaelli C, Pennisi EM, Invernici G, Wessalowski R, Maiwald R, Arca M, Coleman RA. Contribution of novel ATGL missense mutations to the clinical phenotype of NLSD-M: a strikingly low amount of lipase activity may preserve cardiac function. Hum Mol Genet 2012; 21:5318-28. [PMID: 22990388 DOI: 10.1093/hmg/dds388] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The lack of adipose triglyceride lipase (ATGL), a patatin-like phospholipase domain-containing enzyme that hydrolyzes fatty acids from triacylglycerol (TAG) stored in multiple tissues, causes the autosomal recessive disorder neutral lipid storage disease with myopathy (NLSD-M). In two families of Lebanese and Italian origin presenting with NLSD-M, we identified two new missense mutations in highly conserved regions of ATGL (p.Arg221Pro and p.Asn172Lys) and a novel nonsense mutation (p.Trp8X). The Lebanese patients harbor homozygous p.Arg221Pro, whereas the Italian patients are heterozygotes for p.Asn172Lys and the p.Trp8X mutation. The p.Trp8X mutation results in a complete absence of ATGL protein, while the p.Arg221Pro and p.Asn172Lys mutations result in proteins with minimal lipolytic activity. Although these mutations did not affect putative catalytic residues or the lipid droplet (LD)-binding domain of ATGL, cytosolic LDs accumulated in cultured skin fibroblasts from the patients. The missense mutations might destabilize a random coil (p.Asn172Lys) or a helix (p.Arg221Pro) structure within or proximal to the patatin domain of the lipase, thereby interfering with the enzyme activity, while leaving intact the residues required to localize the protein to LDs. Overexpressing wild-type ATGL in one patient's fibroblasts corrected the metabolic defect and effectively reduced the number and area of cellular LDs. Despite the poor lipase activity in vitro, the Lebanese siblings have a mild myopathy and not clinically evident myocardial dysfunction. The patients of Italian origin show a late-onset and slowly progressive skeletal myopathy. These findings suggest that a small amount of correctly localized lipase activity preserves cardiac function in NLSD-M.
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Affiliation(s)
- Daniela Tavian
- Laboratory of Human Molecular Biology and Genetics, Catholic University of the Sacred Heart, Milan, Italy.
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35
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Novel PNPLA2 gene mutations in Chinese Han patients causing neutral lipid storage disease with myopathy. J Hum Genet 2012; 57:679-81. [PMID: 22832386 DOI: 10.1038/jhg.2012.84] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neutral lipid storage disease with myopathy (NLSDM) referred to those neutral lipid storage disease (NLSD) patients with myopathy but without ichthyosis. Recently, NLSDM has been attributed to mutations in the PNPLA2 gene. Until now, 19 patients with PNPLA2 mutations have been reported. In the present study, we describe the clinical and genetic findings in three Chinese patients with NLSDM. Sequence analysis of PNPLA2 gene was performed. In our patients we identified four novel mutations in the PNPLA2 gene including two splicing mutations. The identification and study of mutations found in PNPLA2 is also particularly important to define the clinical spectrum and genotype-phenotype correlations of the PNPLA2 gene.
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36
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Hancks DC, Kazazian HH. Active human retrotransposons: variation and disease. Curr Opin Genet Dev 2012; 22:191-203. [PMID: 22406018 DOI: 10.1016/j.gde.2012.02.006] [Citation(s) in RCA: 431] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 01/18/2012] [Accepted: 02/06/2012] [Indexed: 12/12/2022]
Abstract
Mobile DNAs, also known as transposons or 'jumping genes', are widespread in nature and comprise an estimated 45% of the human genome. Transposons are divided into two general classes based on their transposition intermediate (DNA or RNA). Only one subclass, the non-LTR retrotransposons, which includes the Long INterspersed Element-1 (LINE-1 or L1), is currently active in humans as indicated by 96 disease-causing insertions. The autonomous LINE-1 is capable of retrotransposing not only a copy of its own RNA in cis but also other RNAs (Alu, SINE-VNTR-Alu (SVA), U6) in trans to new genomic locations through an element encoded reverse transcriptase. L1 can also retrotranspose cellular mRNAs, resulting in processed pseudogene formation. Here, we highlight recent reports that update our understanding of human L1 retrotransposition and their role in disease. Finally we discuss studies that provide insights into the past and current activity of these retrotransposons, and shed light on not just when, but where, retrotransposition occurs and its part in genetic variation.
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Affiliation(s)
- Dustin C Hancks
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, United States
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37
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Saini-Chohan HK, Mitchell RW, Vaz FM, Zelinski T, Hatch GM. Delineating the role of alterations in lipid metabolism to the pathogenesis of inherited skeletal and cardiac muscle disorders: Thematic Review Series: Genetics of Human Lipid Diseases. J Lipid Res 2011; 53:4-27. [PMID: 22065858 DOI: 10.1194/jlr.r012120] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As the specific composition of lipids is essential for the maintenance of membrane integrity, enzyme function, ion channels, and membrane receptors, an alteration in lipid composition or metabolism may be one of the crucial changes occurring during skeletal and cardiac myopathies. Although the inheritance (autosomal dominant, autosomal recessive, and X-linked traits) and underlying/defining mutations causing these myopathies are known, the contribution of lipid homeostasis in the progression of these diseases needs to be established. The purpose of this review is to present the current knowledge relating to lipid changes in inherited skeletal muscle disorders, such as Duchenne/Becker muscular dystrophy, myotonic muscular dystrophy, limb-girdle myopathic dystrophies, desminopathies, rostrocaudal muscular dystrophy, and Dunnigan-type familial lipodystrophy. The lipid modifications in familial hypertrophic and dilated cardiomyopathies, as well as Barth syndrome and several other cardiac disorders associated with abnormal lipid storage, are discussed. Information on lipid alterations occurring in these myopathies will aid in the design of improved methods of screening and therapy in children and young adults with or without a family history of genetic diseases.
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Affiliation(s)
- Harjot K Saini-Chohan
- Department of Pharmacology and Therapeutics, Academic Medical Center, Amsterdam, The Netherlands
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38
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Coleman RA, Mashek DG. Mammalian triacylglycerol metabolism: synthesis, lipolysis, and signaling. Chem Rev 2011; 111:6359-86. [PMID: 21627334 PMCID: PMC3181269 DOI: 10.1021/cr100404w] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Rosalind A Coleman
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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Pathogenic exon-trapping by SVA retrotransposon and rescue in Fukuyama muscular dystrophy. Nature 2011; 478:127-31. [PMID: 21979053 PMCID: PMC3412178 DOI: 10.1038/nature10456] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 08/12/2011] [Indexed: 12/23/2022]
Abstract
Fukuyama muscular dystrophy (FCMD; MIM253800), one of the most common autosomal recessive disorders in Japan, was the first human disease found to result from ancestral insertion of a SINE-VNTR-Alu (SVA) retrotransposon into a causative gene1-3. In FCMD, the SVA insertion occurs in the 3′-untranslated region (UTR) of the fukutin gene. The pathogenic mechanism for FCMD is unknown, and no effective clinical treatments exist. Here we show that aberrant mRNA splicing, induced by SVA exon-trapping, underlies the molecular pathogenesis of FCMD. Quantitative mRNA analysis pinpointed a region that was missing from transcripts in FCMD patients. This region spans part of the 3′ end of the fukutin coding region, proximal part of the 3′ UTR, and the SVA insertion. Correspondingly, fukutin mRNA transcripts in FCMD patients and SVA knock-in (KI) model mice were shorter than the expected length. Sequence analysis revealed an abnormal splicing event, provoked by a strong acceptor site in SVA and a rare alternative donor site in fukutin exon 10. The resulting product truncates the fukutin C-terminus and adds 129 amino acids encoded by the SVA. Introduction of antisense oligonucleotides (AONs) targeting the splice acceptor, the predicted exonic splicing enhancer, and the intronic splicing enhancer prevented pathogenic exon-trapping by SVA in FCMD patient cells and model mice, rescuing normal fukutin mRNA expression and protein production. AON treatment also restored fukutin functions, including O-glycosylation of α-dystroglycan (α-DG) and laminin binding by α-DG. Moreover, we observe exon-trapping in other SVA insertions associated with disease (hypercholesterolemia4, neutral lipid storage disease5) and human-specific SVA insertion in a novel gene. Thus, although splicing into SVA is known6-8, we have discovered in human disease a role for SVA-mediated exon-trapping and demonstrated the promise of splicing modulation therapy as the first radical clinical treatment for FCMD and other SVA-mediated diseases.
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DiMauro S, Spiegel R. Progress and problems in muscle glycogenoses. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2011; 30:96-102. [PMID: 22106711 PMCID: PMC3235878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In this selective review, we consider a number of unsolved questions regarding the glycogen storage diseases (GSD). Thus, the pathogenesis of Pompe disease (GSD II) is not simply explained by excessive intralysosomal glycogen storage and may relate to a more general dysfunction of autophagy. It is not clear why debrancher deficiency (GSD III) causes fixed myopathy rather than exercise intolerance, unless this is due to the frequent accompanying neuropathy. The infantile neuromuscular presentation of branching enzyme deficiency (GSD IV) is underdiagnosed and is finally getting the attention it deserves. On the other hand, the late-onset variant of GSD IV (adult polyglucosan body disease APBD) is one of several polyglucosan disorders (including Lafora disease) due to different etiologies. We still do not understand the clinical heterogeneity of McArdle disease (GSD V) or the molecular basis of the rare fatal infantile form. Similarly, the multisystemic infantile presentation of phosphofructokinase deficiency (GSD VII) is a conundrum. We observed an interesting association between phosphoglycerate kinase deficiency (GSD IX) and juvenile Parkinsonism, which is probably causal rather than casual. Also unexplained is the frequent and apparently specific association of phosphoglycerate mutase deficiency (GSD X) and tubular aggregates. By paying more attention to problems than to progress, we aimed to look to the future rather than to the past.
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Affiliation(s)
- S. DiMauro
- Address for correspondence: Salvatore DiMauro, MD, 4-424B College of Physicians & Surgeons, 630 West 168th Street, New York, NY
10032, USA. Tel. +212 305 1662. Fax +212 305 3986. E-mail:
| | - R. Spiegel
- Department of Pediatrics, HaEmek Medical
Center, Rappaport School of Medicine, Afula, Israel
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Hancks DC, Goodier JL, Mandal PK, Cheung LE, Kazazian HH. Retrotransposition of marked SVA elements by human L1s in cultured cells. Hum Mol Genet 2011; 20:3386-400. [PMID: 21636526 DOI: 10.1093/hmg/ddr245] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human retrotransposons generate structural variation and genomic diversity through ongoing retrotransposition and non-allelic homologous recombination. Cell culture retrotransposition assays have provided great insight into the genomic impact of retrotransposons, in particular, LINE-1(L1) and Alu elements; however, no such assay exists for the youngest active human retrotransposon, SINE-VNTR-Alu (SVA). Here we report the development of an SVA cell culture retrotransposition assay. We marked several SVAs with either neomycin or EGFP retrotransposition indicator cassettes. Engineered SVAs retrotranspose using L1 proteins supplemented in trans in multiple cell lines, including U2OS osteosarcoma cells where SVA retrotransposition is equal to that of an engineered L1. Engineered SVAs retrotranspose at 1-54 times the frequency of a marked pseudogene in HeLa HA cells. Furthermore, our data suggest a variable requirement for L1 ORF1p for SVA retrotransposition. Recovered engineered SVA insertions display all the hallmarks of LINE-1 retrotransposition and some contain 5' and 3' transductions, which are common for genomic SVAs. Of particular interest is the fact that four out of five insertions recovered from one SVA are full-length, with the 5' end of these insertions beginning within 5 nt of the CMV promoter transcriptional start site. This assay demonstrates that SVA elements are indeed mobilized in trans by L1. Previously intractable questions regarding SVA biology can now be addressed.
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Affiliation(s)
- Dustin C Hancks
- Cell and Molecular Biology Graduate Group, The University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Reilich P, Horvath R, Krause S, Schramm N, Turnbull DM, Trenell M, Hollingsworth KG, Gorman GS, Hans VH, Reimann J, MacMillan A, Turner L, Schollen A, Witte G, Czermin B, Holinski-Feder E, Walter MC, Schoser B, Lochmüller H. The phenotypic spectrum of neutral lipid storage myopathy due to mutations in the PNPLA2 gene. J Neurol 2011; 258:1987-97. [DOI: 10.1007/s00415-011-6055-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/07/2011] [Accepted: 04/10/2011] [Indexed: 12/29/2022]
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Radner FP, Grond S, Haemmerle G, Lass A, Zechner R. Fat in the skin: Triacylglycerol metabolism in keratinocytes and its role in the development of neutral lipid storage disease. DERMATO-ENDOCRINOLOGY 2011; 3:77-83. [PMID: 21695016 PMCID: PMC3117006 DOI: 10.4161/derm.3.2.15472] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/10/2011] [Accepted: 03/11/2011] [Indexed: 12/11/2022]
Abstract
Keratinocyte differentiation is essential for skin development and the formation of the skin permeability barrier. This process involves an orchestrated remodeling of lipids. The cleavage of precursor lipids from lamellar bodies by β-glucocerebrosidase, sphingomyelinase, phospholipases and sterol sulfatase generates ceramides, non-esterified fatty acids and cholesterol for the lipid-containing extracellular matrix, the lamellar membranes in the stratum corneum. The importance of triacylglycerol (TAG) hydrolysis for the formation of a functional permeability barrier was only recently appreciated. Mice with defects in TAG synthesis (acyl-CoA:diacylglycerol acyltransferase-2-knock-out) or TAG catabolism (comparative gene identification-58, -CGI-58-knock-out) develop severe permeability barrier defects and die soon after birth because of desiccation. In humans, mutations in the CGI-58 gene also cause (non-lethal) neutral lipid storage disease with ichthyosis. As a result of defective TAG synthesis or catabolism, humans and mice lack ω-(O)-acylceramides, which are essential lipid precursors for the formation of the corneocyte lipid envelope. This structure plays an important role in linking the lipid-enriched lamellar membranes to highly cross-linked corneocyte proteins. This review focuses on the current knowledge of biochemical mechanisms that are essential for epidermal neutral lipid metabolism and the formation of a functional skin permeability barrier.
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Affiliation(s)
- Franz Pw Radner
- Institute of Molecular Biosciences; University of Graz; Graz, Austria
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Coassin S, Schweiger M, Kloss-Brandstätter A, Lamina C, Haun M, Erhart G, Paulweber B, Rahman Y, Olpin S, Wolinski H, Cornaciu I, Zechner R, Zimmermann R, Kronenberg F. Investigation and functional characterization of rare genetic variants in the adipose triglyceride lipase in a large healthy working population. PLoS Genet 2010; 6:e1001239. [PMID: 21170305 PMCID: PMC3000363 DOI: 10.1371/journal.pgen.1001239] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 11/04/2010] [Indexed: 12/14/2022] Open
Abstract
Recent studies demonstrated a strong influence of rare genetic variants on several lipid-related traits. However, their impact on free fatty acid (FFA) plasma concentrations, as well as the role of rare variants in a general population, has not yet been thoroughly addressed. The adipose triglyceride lipase (ATGL) is encoded by the PNPLA2 gene and catalyzes the rate-limiting step of lipolysis. It represents a prominent candidate gene affecting FFA concentrations. We therefore screened the full genomic region of ATGL for mutations in 1,473 randomly selected individuals from the SAPHIR (Salzburg Atherosclerosis Prevention program in subjects at High Individual Risk) Study using a combined Ecotilling and sequencing approach and functionally investigated all detected protein variants by in-vitro studies. We observed 55 novel mostly rare genetic variants in this general population sample. Biochemical evaluation of all non-synonymous variants demonstrated the presence of several mutated but mostly still functional ATGL alleles with largely varying residual lipolytic activity. About one-quarter (3 out of 13) of the investigated variants presented a marked decrease or total loss of catalytic function. Genetic association studies using both continuous and dichotomous approaches showed a shift towards lower plasma FFA concentrations for rare variant carriers and an accumulation of variants in the lower 10%-quantile of the FFA distribution. However, the generally rather small effects suggest either only a secondary role of rare ATGL variants on the FFA levels in the SAPHIR population or a recessive action of ATGL variants. In contrast to these rather small effects, we describe here also the first patient with “neutral lipid storage disease with myopathy” (NLSDM) with a point mutation in the catalytic dyad, but otherwise intact protein. The nature of the genetic variation underlying common traits is not yet completely understood. Recently, there has been a shift in the genetic research focus towards the elucidation of the influence of rare variants, which are thought to exert a strong impact on common traits. Circulating free fatty acids are immediate products of the triglyceride breakdown and represent a yet poorly addressed phenotype to study the impact of rare variants on lipolysis. Since ATGL (encoded by the PNPLA2 gene) controls the rate limiting step of lipolysis, we screened its whole gene region in 1,473 healthy individuals and found that 1 out of 13 individuals indeed carried at least one rare mutation. Biochemical investigations showed that, even in a healthy population, several missense variants lead to an impaired catalytic activity and 1 variant even produced a completely inactive protein. However, subsequent association studies revealed only small effects on the free fatty acids levels in the population. This suggests an only secondary role of rare ATGL variants on free fatty acids levels. More generally, we conclude that even in a healthy population pronounced allelic heterogeneity due to the presence of several rare variants may be common.
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Affiliation(s)
- Stefan Coassin
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Anita Kloss-Brandstätter
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Claudia Lamina
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Margot Haun
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Gertraud Erhart
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Bernhard Paulweber
- First Department of Internal Medicine, Paracelsus Private Medical University Salzburg, Salzburg, Austria
| | - Yusof Rahman
- Department of Inherited Metabolic Diseases, Evelina Children Hospital, Guys and St. Thomas's National Health Service Foundation Trust, London, United Kingdom
| | - Simon Olpin
- Department of Clinical Chemistry, Sheffield Children's Hospital, Sheffield, United Kingdom
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Irina Cornaciu
- Structural Biology Group, Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Florian Kronenberg
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
- * E-mail:
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Abstract
We consider recent developments in disorders affecting three areas of metabolism: glycogen, fatty acids, and the mitochondrial respiratory chain. Among the glycogenoses, new attention has been directed to defects of glycogen synthesis resulting in absence rather than excess of muscle glycogen ("aglycogenosis"). These include defects of glycogen synthetase and defects of glycogenin, the primer of glycogen synthesis. Considerable progress also has been made in our understanding of alterations of glycogen metabolism that result in polyglucosan storage. Among the disorders of lipid metabolism, mutations in the genes encoding two triglyceride lipases acting hand in hand cause severe generalized lipid storage myopathy, one associated with ichthyosis (Chanarin-Dorfman syndrome), the other dominated by juvenile-onset weakness. For the mitochondrial myopathies, we discuss the importance of homoplasmic mitochondrial DNA mutations and review the rapid progress made in our understanding of the coenzyme Q(10) deficiencies, which are often treatable.
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Affiliation(s)
- Salvatore DiMauro
- Department of Neurology, College of Physicians and Surgeons, Columbia University Medical Center, Room 4-424B, 630 West 168th Street, New York, NY 10032, USA.
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