X-linked myotubular myopathy associated with an MTM1 variant in a Maine coon cat
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Date
2022-09-26
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine
Rights
(c) 2022 The Author/s
CC BY-NC 4.0
CC BY-NC 4.0
Abstract
OBJECTIVE: Describe the clinical course and diagnostic and genetic findings in a cat with X-linked myotubular myopathy.
CASE SUMMARY: A 7-month-old male Maine coon was evaluated for progressively worsening gait abnormalities and generalized weakness. Neurolocalization was to the neuromuscular system. Genetic testing for spinal muscular atrophy (LIX1) was negative. Given the progressive nature and suspected poor long-term prognosis, the owners elected euthanasia. Histopathology of skeletal muscle obtained post-mortem disclosed numerous rounded atrophic or hypotrophic fibers with internal nuclei or central basophilic staining. Using oxidative reactions mediated by cytochrome C oxidase and succinic dehydrogenase, scattered myofibers were observed to have central dark staining structures and a "ring-like" appearance. Given the cat's age and clinical history, a congenital myopathy was considered most likely, with the central nuclei and "ring-like" changes consistent with either centronuclear or myotubular myopathy. Whole genome sequencing identified an underlying missense variant in myotubularin 1 (MTM1), a known candidate gene for X-linked myotubular myopathy.
NEW OR UNIQUE INFORMATION PROVIDED: This case is the first report of X-linked myotubular myopathy in a cat with an MTM1 missense mutation. Maine coon cat breeders may consider screening for this variant to prevent production of affected cats and to eradicate the variant from the breeding population.
Description
Keywords
CNM, XLMTM, congenital, feline, immunohistochemistry, skeletal muscle, Animals, Cat Diseases, Cats, Electron Transport Complex IV, Male, Muscle, Skeletal, Myopathies, Structural, Congenital, Protein Tyrosine Phosphatases, Non-Receptor, Succinate Dehydrogenase
Citation
Kopke MA, Shelton GD, Lyons LA, Wall MJ, Pemberton S, Gedye KR, Owen R, Guo LT, Buckley RM, Valencia JA, 99 Lives Consortium , Jones BR. (2022). X-linked myotubular myopathy associated with an MTM1 variant in a Maine coon cat.. J Vet Intern Med. 36. 5. (pp. 1800-1805).