Felis ISSN 2398-2950

Muscular dystrophy

Synonym(s): MD

Contributor(s): Laurent Garosi, Simon Platt

Introduction

  • Cause: heterogenous group of inherited, degenerative, mostly non-inflammatory muscle diseases.
  • Signs: progressive muscle stiffness, contracture, lingual hypertrophy, muscle atrophy or hypertrophy, cardiomyopathy.
  • Diagnosis: elevated serum creatinine kinase (CK), muscle biopsy.
  • Treatment: no specific treatment.
  • Prognosis: poor prognosis, progressively fatal disease.
    Print off the owner factsheet on Muscular dystrophies  Muscular dystrophies  to give to your client.

Pathogenesis

Etiology

  • Heterogenous group of more than 30 hereditary degenerative myopathies Myopathies.
  • To date 4 forms of muscular dystrophy identified in cats: feline X-linked dystrophin deficiency, merosin (laminin alpha2) deficiency, sarcoglycan deficiency and dystroglycan deficiency.
  • Dystrophin deficiency is associated with genetic mutations of the dystrophin gene.
  • Dystrophin gene is located on X-chromosome => dystrophin muscular dystrophy is an X-linked recessive trait transmitted by a female carrier.

Pathophysiology

  • Dystrophin links the myofiber cytoskeleton to the extracellular matrix and is essential in stabilization of the muscle fiber membranes during contraction.
  • Mutations of genes coding for dystrophin or its associated proteins => disruption of the dystrophin-glycoprotein complex => membrane instability => leakage of intracellular contents into the extracellular fluid space and skeletal and cardiac muscle fiber damage.
  • Laminin alpha2 is the major component of the basal lamina that surrounds each muscle fiber and one of the extracellular ligands for the dystrophin-associated glycoprotein complex => links dystrophin to the extracellular matrix and contributes to the stability of the muscle basement membrane.
  • Dystroglycan is a central part of the dystrophin-glycoprotein (DAG) complex - it is an extracellular membrane associated protein which binds to a variety of extracellular proteins including laminin alpha2.

Timecourse

  • Signs usually develop in first 3-6 months of life and are most often rapidly progressive.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gambino A N, Mouser P J, Shelton G D et al (2014) Emergent presentation of a cat with dystrophin-deficient muscular dystrophy. J Am Anim Hosp Assoc 50 (2), 130-135 PubMed.
  • Blunden A S & Gower S (2011) Hypertrophic feline muscular dystrophy: diagnostic overview and a novel immunohistochemical diagnostic method using formalin-fixed tissue. Vet Rec 168 (19), 510 PubMed.
  • Salvadori C, Vattemi G, Lombardo R et al (2009) Muscular dystrophy with reduced beta-sarcoglycan in a cat. J Comp Pathol 140 (4), 278-282 PubMed.
  • Martin P T, Shelton G D, Dickinson P J et al (2008) Muscular dystrophy associated with alpha-dystroglycan deficiency in Sphynx and Devon Rex cats. Neuromuscular Disor 18 (12), 942-952 PubMed.
  • Schatzberg S J & Shelton G D (2004) Newly identified neuromuscular disorders. Vet Clin North Am Small Anim Pract 34 (6), 1497-1524 PubMed.
  • Poncelet L, Résibois A, Engvall E et al (2003) Laminin alpha2 deficiency-associated muscular dystrophy in a Maine coon cat. J Small Anim Pract 44 (12), 550-552 PubMed.
  • Shelton G D & Engvall E (2002) Muscular dystrophies and other inherited myopathies. Vet Clin North Am Small Anim Pract 32 (1), 103-124 PubMed.


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