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Murthy VD, McLarty E, Woolard KD, Parker RL, Kortz G, King JN, Poppenga RH, Knipe MF, Dickinson PJ. Case Report: MRI, Clinical, and Pathological Correlates of Bromethalin Toxicosis in Three Dogs. Front Vet Sci 2022; 9:879007. [PMID: 35558887 PMCID: PMC9087846 DOI: 10.3389/fvets.2022.879007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/16/2022] [Indexed: 11/13/2022] Open
Abstract
Bromethalin toxicosis is an increasingly common clinical presentation in dogs that may be fatal depending on the extent of intoxication. Antemortem diagnosis of bromethalin toxicosis was achieved in three dogs by demonstration of the active metabolite desmethylbromethalin in fat or serum. Magnetic resonance imaging (MRI) findings were consistent with a diffuse leukoencephalopathy with restricted diffusion and prominent involvement of the corticospinal motor tracts on T2-weighted and diffusion-weighted sequences. Imaging findings were confirmed in one non-surviving dog at necropsy. Resolution of MRI abnormalities was demonstrated in one surviving dog that was consistent with the associated resolution of clinical signs. Initial findings in these dogs support further investigation of specific MRI patterns in cases of leukoencephalopathy to aid differential diagnosis. While antemortem detection of bromethalin and its metabolites confirms exposure, quantitation may be informative as a prognostic biomarker.
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Affiliation(s)
- Vishal D. Murthy
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- *Correspondence: Vishal D. Murthy
| | - Ehren McLarty
- Department of Surgical and Radiological Sciences, University of California, Davis, Davis, CA, United States
| | - Kevin D. Woolard
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
| | - Rell L. Parker
- Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Gregg Kortz
- Department of Neurology, VCA Sacramento Veterinary Referral Center, Sacramento, CA, United States
| | - Jamie N. King
- Department of Neurology, VCA Sacramento Veterinary Referral Center, Sacramento, CA, United States
| | - Robert H. Poppenga
- California Animal Health and Food Safety Laboratory System, University of California, Davis, Davis, CA, United States
| | - Marguerite F. Knipe
- Department of Surgical and Radiological Sciences, University of California, Davis, Davis, CA, United States
| | - Peter J. Dickinson
- Department of Surgical and Radiological Sciences, University of California, Davis, Davis, CA, United States
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Quitt PR, Brühschwein A, Matiasek K, Wielaender F, Karkamo V, Hytönen MK, Meyer-Lindenberg A, Dengler B, Leeb T, Lohi H, Fischer A. A hypomyelinating leukodystrophy in German Shepherd dogs. J Vet Intern Med 2021; 35:1455-1465. [PMID: 33734486 PMCID: PMC8163122 DOI: 10.1111/jvim.16085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/07/2021] [Accepted: 02/17/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Shaking puppy syndrome is commonly attributed to abnormal myelination of the central nervous system. HYPOTHESIS/OBJECTIVES To report the long-term clinical course and the imaging characteristics of hypomyelinating leukodystrophy in German Shepherd dogs. ANIMALS AND METHODS Three related litters with 11 affected dogs. RESULTS The 11 affected dogs experienced coarse, side-to-side tremors of the head and trunk, which interfered with normal goal-oriented movements and disappeared at rest. Signs were noticed shortly after birth. Nine dogs were euthanized, 3 dogs underwent pathological examination, and 2 littermates were raised by their breeder. Tremors improved gradually until 6 to 7 months of age. Adult dogs walked with severe residual pelvic limb ataxia. One dog developed epilepsy with tonic-clonic seizures at 15 months of age. Conventional magnetic resonance imaging (MRI) disclosed homogenous hyperintense signal of the entire subcortical white matter in 3 affected 7-week-old dogs and a hypointense signal in a presumably unaffected littermate. Subcortical white matter appeared isointense to gray matter at 15 and 27 weeks of age on repeated MRI. Abnormal white matter signal with failure to display normal gray-white matter contrast persisted into adulthood. Cerebellar arbor vitae was not visible at any time point. Clinical signs, MRI findings, and pathological examinations were indicative of a hypomyelinating leukodystrophy. All parents of the affected litters shared a common ancestor and relatedness of the puppies suggested an autosomal recessive mode of inheritance. CONCLUSION We describe a novel hypomyelinating leukodystrophy in German Shepherd dogs with a suspected inherited origin.
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Affiliation(s)
- Pia R Quitt
- Centre for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
| | - Andreas Brühschwein
- Centre for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
| | - Kaspar Matiasek
- Section of Clinical and Comparative Pathology, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
| | - Franziska Wielaender
- Centre for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
| | - Veera Karkamo
- Production and Companion Animal Pathology Section, Finnish Food Authority, Helsinki, Finland
| | - Marjo K Hytönen
- Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.,Folkhälsan Research Center, Helsinki, Finland
| | - Andrea Meyer-Lindenberg
- Centre for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
| | - Berett Dengler
- Centre for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Hannes Lohi
- Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.,Folkhälsan Research Center, Helsinki, Finland
| | - Andrea Fischer
- Centre for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, LMU Munich, Munich, Germany
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TSEN54 missense variant in Standard Schnauzers with leukodystrophy. PLoS Genet 2019; 15:e1008411. [PMID: 31584937 PMCID: PMC6795476 DOI: 10.1371/journal.pgen.1008411] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/16/2019] [Accepted: 09/10/2019] [Indexed: 12/13/2022] Open
Abstract
We report a hereditary leukodystrophy in Standard Schnauzer puppies. Clinical signs occurred shortly after birth or started at an age of under 4 weeks and included apathy, dysphoric vocalization, hypermetric ataxia, intension tremor, head tilt, circling, proprioceptive deficits, seizures and ventral strabismus consistent with a diffuse intracranial lesion. Magnetic resonance imaging revealed a diffuse white matter disease without mass effect. Macroscopically, the cerebral white matter showed a gelatinous texture in the centrum semiovale. A mild hydrocephalus internus was noted. Histopathologically, a severe multifocal reduction of myelin formation and moderate diffuse edema without inflammation was detected leading to the diagnosis of leukodystrophy. Combined linkage analysis and homozygosity mapping in two related families delineated critical intervals of approximately 29 Mb. The comparison of whole genome sequence data of one affected Standard Schnauzer to 221 control genomes revealed a single private homozygous protein changing variant in the critical intervals, TSEN54:c.371G>A or p.(Gly124Asp). TSEN54 encodes the tRNA splicing endonuclease subunit 54. In humans, several variants in TSEN54 were reported to cause different types of pontocerebellar hypoplasia. The genotypes at the c.371G>A variant were perfectly associated with the leukodystrophy phenotype in 12 affected Standard Schnauzers and almost 1000 control dogs from different breeds. These results suggest that TSEN54:c.371G>A causes the leukodystrophy. The identification of a candidate causative variant enables genetic testing so that the unintentional breeding of affected Standard Schnauzers can be avoided in the future. Our findings extend the known genotype-phenotype correlation for TSEN54 variants. Various hereditary diseases of the cerebral white matter occur in humans and dogs. We describe a new leukodystrophy in Standard Schnauzers. Genetic mapping and whole genome sequence analysis identified a likely candidate causative variant in the TSEN54 gene encoding tRNA splicing endonuclease 54. These results provide new information about the role of TSEN54 in cell metabolism and the development of the central nervous system in the late gestational and early post-natal period. The affected dogs potentially represent a translational large animal model for similar leukoencephalopathies in human medicine. The clinical phenotype in Schnauzers included multifocal central nervous system signs. A holistic pathogenically driven understanding of disease initiation and perpetuation requires a solid analysis of the underlying genetics and characterization of the disease phenotype at the clinical and cellular as well as sub-cellular level. In contrast to the canine phenotype with a predominant manifestation in the cerebrum white matter, other TSEN54 variants in humans have been reported to result in a different pathological phenotype characterized by pontocerebellar hypoplasia. The differences between humans and dogs underscore the need for comparative analysis at the clinical, pathological and molecular level to understand species-specific protein mediated pathways, interactions and outcomes.
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Minor KM, Letko A, Becker D, Drögemüller M, Mandigers PJJ, Bellekom SR, Leegwater PAJ, Stassen QEM, Putschbach K, Fischer A, Flegel T, Matiasek K, Ekenstedt KJ, Furrow E, Patterson EE, Platt SR, Kelly PA, Cassidy JP, Shelton GD, Lucot K, Bannasch DL, Martineau H, Muir CF, Priestnall SL, Henke D, Oevermann A, Jagannathan V, Mickelson JR, Drögemüller C. Canine NAPEPLD-associated models of human myelin disorders. Sci Rep 2018; 8:5818. [PMID: 29643404 PMCID: PMC5895582 DOI: 10.1038/s41598-018-23938-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/20/2018] [Indexed: 01/05/2023] Open
Abstract
Canine leukoencephalomyelopathy (LEMP) is a juvenile-onset neurodegenerative disorder of the CNS white matter currently described in Rottweiler and Leonberger dogs. Genome-wide association study (GWAS) allowed us to map LEMP in a Leonberger cohort to dog chromosome 18. Subsequent whole genome re-sequencing of a Leonberger case enabled the identification of a single private homozygous non-synonymous missense variant located in the highly conserved metallo-beta-lactamase domain of the N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD) gene, encoding an enzyme of the endocannabinoid system. We then sequenced this gene in LEMP-affected Rottweilers and identified a different frameshift variant, which is predicted to replace the C-terminal metallo-beta-lactamase domain of the wild type protein. Haplotype analysis of SNP array genotypes revealed that the frameshift variant was present in diverse haplotypes in Rottweilers, and also in Great Danes, indicating an old origin of this second NAPEPLD variant. The identification of different NAPEPLD variants in dog breeds affected by leukoencephalopathies with heterogeneous pathological features, implicates the NAPEPLD enzyme as important in myelin homeostasis, and suggests a novel candidate gene for myelination disorders in people.
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Affiliation(s)
- K M Minor
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, 55108, USA
| | - A Letko
- Institute of Genetics, University of Bern, Bern, 3001, Switzerland
| | - D Becker
- Institute of Genetics, University of Bern, Bern, 3001, Switzerland
| | - M Drögemüller
- Institute of Genetics, University of Bern, Bern, 3001, Switzerland
| | - P J J Mandigers
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, 3508, CM, The Netherlands
| | - S R Bellekom
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, 3508, CM, The Netherlands
| | - P A J Leegwater
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, 3508, CM, The Netherlands
| | - Q E M Stassen
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, 3508, CM, The Netherlands
| | - K Putschbach
- Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Munich, 80539, Germany
| | - A Fischer
- Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Munich, 80539, Germany
| | - T Flegel
- Department of Small Animal Medicine, University of Leipzig, Leipzig, 04103, Germany
| | - K Matiasek
- Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Munich, 80539, Germany
| | - K J Ekenstedt
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - E Furrow
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, 55108, USA
| | - E E Patterson
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, 55108, USA
| | - S R Platt
- Small Animal Medicine and Surgery, University of Georgia, Athens, GA, 30602, USA
| | - P A Kelly
- Veterinary Sciences Centre, University College Dublin, Dublin, D04 V1W8, Ireland
| | - J P Cassidy
- Veterinary Sciences Centre, University College Dublin, Dublin, D04 V1W8, Ireland
| | - G D Shelton
- Department of Pathology, University of California, La Jolla, CA, 92093, USA
| | - K Lucot
- Department of Population Health and Reproduction, University of California-Davis, Davis, CA, 95616, USA
| | - D L Bannasch
- Department of Population Health and Reproduction, University of California-Davis, Davis, CA, 95616, USA
| | - H Martineau
- Pathobiology and Population Sciences, The Royal Veterinary College, North Mymms, AL9 7TA, UK
| | - C F Muir
- Pathobiology and Population Sciences, The Royal Veterinary College, North Mymms, AL9 7TA, UK
| | - S L Priestnall
- Pathobiology and Population Sciences, The Royal Veterinary College, North Mymms, AL9 7TA, UK
| | - D Henke
- Division of Clinical Neurology, University of Bern, Bern, 3001, Switzerland
| | - A Oevermann
- Division of Neurological Sciences, University of Bern, Bern, 3001, Switzerland
| | - V Jagannathan
- Institute of Genetics, University of Bern, Bern, 3001, Switzerland
| | - J R Mickelson
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, 55108, USA
| | - C Drögemüller
- Institute of Genetics, University of Bern, Bern, 3001, Switzerland.
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