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Walmsley GL, Blot S, Venner K, Sewry C, Laporte J, Blondelle J, Barthélémy I, Maurer M, Blanchard-Gutton N, Pilot-Storck F, Tiret L, Piercy RJ. Progressive Structural Defects in Canine Centronuclear Myopathy Indicate a Role for HACD1 in Maintaining Skeletal Muscle Membrane Systems. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 187:441-456. [PMID: 27939133 DOI: 10.1016/j.ajpath.2016.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 11/16/2022]
Abstract
Mutations in HACD1/PTPLA cause recessive congenital myopathies in humans and dogs. Hydroxyacyl-coA dehydratases are required for elongation of very long chain fatty acids, and HACD1 has a role in early myogenesis, but the functions of this striated muscle-specific enzyme in more differentiated skeletal muscle remain unknown. Canine HACD1 deficiency is histopathologically classified as a centronuclear myopathy (CNM). We investigated the hypothesis that muscle from HACD1-deficient dogs has membrane abnormalities in common with CNMs with different genetic causes. We found progressive changes in tubuloreticular and sarcolemmal membranes and mislocalized triads and mitochondria in skeletal muscle from animals deficient in HACD1. Furthermore, comparable membranous abnormalities in cultured HACD1-deficient myotubes provide additional evidence that these defects are a primary consequence of altered HACD1 expression. Our novel findings, including T-tubule dilatation and disorganization, associated with defects in this additional CNM-associated gene provide a definitive pathophysiologic link with these disorders, confirm that dogs deficient in HACD1 are relevant models, and strengthen the evidence for a unifying pathogenesis in CNMs via defective membrane trafficking and excitation-contraction coupling in muscle. These results build on previous work by determining further functional roles of HACD1 in muscle and provide new insight into the pathology and pathogenetic mechanisms of HACD1 CNM. Consequently, alterations in membrane properties associated with HACD1 mutations should be investigated in humans with related phenotypes.
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Affiliation(s)
- Gemma L Walmsley
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, United Kingdom.
| | - Stéphane Blot
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Kerrie Venner
- Electron Microscopy Unit, Institute of Neurology, London, United Kingdom
| | - Caroline Sewry
- Dubowitz Neuromuscular Centre, University College London Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institute of Genetics and Cellular and Molecular Biology (IGBMC), Inserm U964, CNRS UMR7104, Strasbourg University, Illkirch, France
| | - Jordan Blondelle
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Inès Barthélémy
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Marie Maurer
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Nicolas Blanchard-Gutton
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Fanny Pilot-Storck
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Laurent Tiret
- French National Institute of Health and Medical Research (Inserm), Mondor Institute of Biomedical Research (IMRB) U955-E10 Biology of the Neuromuscular System, Créteil, France; University of Paris East, Alfort School of Veterinary Medicine (EnvA), Maisons-Alfort, France
| | - Richard J Piercy
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, United Kingdom
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Ekenstedt KJ, Becker D, Minor KM, Shelton GD, Patterson EE, Bley T, Oevermann A, Bilzer T, Leeb T, Drögemüller C, Mickelson JR. An ARHGEF10 deletion is highly associated with a juvenile-onset inherited polyneuropathy in Leonberger and Saint Bernard dogs. PLoS Genet 2014; 10:e1004635. [PMID: 25275565 PMCID: PMC4183422 DOI: 10.1371/journal.pgen.1004635] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 07/18/2014] [Indexed: 11/18/2022] Open
Abstract
An inherited polyneuropathy (PN) observed in Leonberger dogs has clinical similarities to a genetically heterogeneous group of peripheral neuropathies termed Charcot-Marie-Tooth (CMT) disease in humans. The Leonberger disorder is a severe, juvenile-onset, chronic, progressive, and mixed PN, characterized by exercise intolerance, gait abnormalities and muscle atrophy of the pelvic limbs, as well as inspiratory stridor and dyspnea. We mapped a PN locus in Leonbergers to a 250 kb region on canine chromosome 16 (Praw = 1.16×10−10, Pgenome, corrected = 0.006) utilizing a high-density SNP array. Within this interval is the ARHGEF10 gene, a member of the rho family of GTPases known to be involved in neuronal growth and axonal migration, and implicated in human hypomyelination. ARHGEF10 sequencing identified a 10 bp deletion in affected dogs that removes four nucleotides from the 3′-end of exon 17 and six nucleotides from the 5′-end of intron 17 (c.1955_1958+6delCACGGTGAGC). This eliminates the 3′-splice junction of exon 17, creates an alternate splice site immediately downstream in which the processed mRNA contains a frame shift, and generates a premature stop codon predicted to truncate approximately 50% of the protein. Homozygosity for the deletion was highly associated with the severe juvenile-onset PN phenotype in both Leonberger and Saint Bernard dogs. The overall clinical picture of PN in these breeds, and the effects of sex and heterozygosity of the ARHGEF10 deletion, are less clear due to the likely presence of other forms of PN with variable ages of onset and severity of clinical signs. This is the first documented severe polyneuropathy associated with a mutation in ARHGEF10 in any species. Leonberger dogs are a breed originally produced by crossing large-bodied dogs, including Saint Bernards and Newfoundlands. A peripheral neuropathy has been described in Leonbergers that is similar to a group of inherited polyneuropathies known as Charcot-Marie-Tooth disease in humans. We collected a cohort of well-characterized Leonberger polyneuropathy cases and controls, conducted a genome-wide association study, and ultimately identified a highly associated and likely causative mutation in the AHGEF10 gene. This sequence variant is a 10-bp deletion encompassing a splice site, which forces use of a downstream splice site to create a processed mRNA with a premature stop codon, and represents a loss-of-function mutation. The identical mutation was also found in several polyneuropathy-affected Saint Bernards. When homozygous, this deletion results in the onset of clinical signs before four years of age. ARHGEF10 has not previously been associated with severe CMT, but comes from a family of genes shown to be involved in neuron morphology. This first-documented severe polyneuropathy associated with an ARHGEF10 mutation in any species provides an opportunity to gain further insights into the pathobiology of diseases associated with this gene. The ARHGEF10 mutation does not, however, by itself account for all cases of polyneuropathy in Leonbergers or Saint Bernards.
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Affiliation(s)
- Kari J. Ekenstedt
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
| | - Doreen Becker
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Katie M. Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - G. Diane Shelton
- Comparative Neuromuscular Laboratory, Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Edward E. Patterson
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Tim Bley
- Small Animal Clinic, Neruology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Anna Oevermann
- Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Thomas Bilzer
- Institute of Neuropathology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - James R. Mickelson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
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Canine inherited motor and sensory neuropathies: an updated classification in 22 breeds and comparison to Charcot-Marie-Tooth disease. Vet J 2010; 188:274-85. [PMID: 20638305 DOI: 10.1016/j.tvjl.2010.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 06/01/2010] [Accepted: 06/04/2010] [Indexed: 12/15/2022]
Abstract
Canine inherited neuropathies form a group of degenerative diseases affecting motor and/or sensory and autonomic peripheral nerves. There is now a large number of inherited motor and sensory neuropathies (IMSN) reported in the veterinary literature, for which clinical, electrophysiological, histopathological and mode of inheritance data are available. Their resemblance with Charcot-Marie-Tooth disease in humans is suggested, although direct comparison is difficult due to the small number of cases described in each breed and the lack of genetic knowledge in dogs. Charcot-Marie-Tooth disease forms a wide group of hereditary neuropathies for which a genetic mutation is recognised in more than 70% of patients. In dogs, no genetic mutation has so far been identified and the knowledge available for human hereditary neuropathies may be useful to identify genetic mutations in dogs. This review provides an update on data available on inherited neuropathy in Leonberger dogs and three new degenerative neuropathies are briefly described in two Russian Black terriers, two Cocker Spaniels and a Podhale Shepherd dog.
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