Centronuclear Myopathy

Other Names: Hereditary myopathy of the Labrador Retriever, Type II muscle fiber deficiency, CNM
Affected Genes: PTPLA
Inheritance: Autosomal Recessive
Mutation: chr2:19371988-19371989 (canFam3): 236 bp insertion; chr2:19371976-19371988 (canFam3): 13 bp duplication (dup CACACAAAGGTTT)
Breed(s): Australian Cobberdog, Australian Labradoodle, Lab/Golden Cross, Labradoodle, Labrador Retriever, Service/Assistance Lab/Golden Retriever cross, Service/Assistance Labrador Retriever, UK Breed Council Labrador Retriever

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Common Symptoms

Centronuclear Myopathy is an inherited progressive muscle disease known to affect Labrador retrievers. Though severity of symptoms are variable, affected dogs often present with exercise intolerance, awkward gait and difficulty eating, usually within the first few months of life. As the disease progresses, symptoms also include generalized muscle Atrophy, downward flexion of the head and neck, low muscle tone and more frequent episodes of collapse when exposed to cold temperatures. Progression of the disease appears to stabilize around one year of age and dogs typically have a normal life span, but affected dogs usually have life-long medical problems due to the underlying muscle disease.

Testing Tips

Genetic testing of the PTPLA gene will reliably determine whether a Labrador retriever is a genetic Carrier of centronuclear Myopathy. Centronuclear myopathy is known to be inherited in an Autosomal Recessive manner in dogs. Carrier dogs do not have any features of the disease but when bred with another dog that also is a carrier of the same Mutation, there is a risk of having affected pups. For each pup that is born to this pairing, there is a 25% chance of having the disease. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

References

  • Gentilini F, Zambon E, Gandini G, Rosati M, Spadari A, Romagnoli N, Turba ME, Gernone F.Frequency of the allelic variant of the PTPLA gene responsible for centronuclear myopathy in Labrador Retriever dogs as assessed in Italy. J Vet Diagn Invest. 2011 Jan; 23(1):124-6. [PubMed: 21217042]
  • Maurer M, Mary J, Guillaud L, Fender M, Pele M, Bilzer T, Olby N, Penderis J, Shelton GD, Panthier JJ, Thibaud JL, Barthelemy I, Aubin-Houzelstein G, Blot S, Hitte C, Tiret L. Centronuclear myopathy in Labrador retrievers: A recent founder mutation in the PTPLA gene has rapidly disseminated worldwide. PLoS One. 2012;7(10):e46408. doi:10.1371/journal.pone.0046408. [PubMed: 23071563]
  • Pelé M, Tiret L, Kessler JL, Blot S, Panthier JJ. SINE exonic insertion in the PTPLA gene leads to multiple splicing defects and segregates with the autosomal recessive centronuclear myopathy in dogs. Hum Mol Genet. 2005 Jun 1; 14(11):1417-27. [PubMed: 15829503]