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Centronuclear Myopathy (CNM Dog)

Centronuclear Myopathy (CNM) is a hereditary muscle disease in Labrador Retrievers. The disease leads to muscle degeneration, uneven gait and a lack of patellar reflex.

The inheritance is autosomal recessive.

Synonym: Labrador Retriever Myopathy (LRM), hereditary myopathy of labrador retrievers (HMLR).


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  • General weakness
  • Premature fatigue
  • Unsteady gait
  • Absence of patellar reflex
  • Muscle atrophy

General Information

  • Centronuclear Myopathy (CNM) is a hereditary muscle disease in Labrador Retrievers.
  • The first symptoms appear from the 6th month onwards.
  • Affected animals have health problems that severely affect their quality of life.

Breeds affected

Labrador Retriever

Test Information

This mutation test detects a SINE insertion in exon 2 of the PTPLA gene.


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Genotype and Lab Report

Inheritance: autosomal recessive

→ The disease only occurs when both alleles of the gene are affected by the mutation (cnm/cnm). Dogs that have only one allele with the causative mutation (N/cnm) are clinically healthy carriers.


N/N = genetically normal

The dog has no variants for CNM and thus cannot pass it on to offspring.

N/cnm = a carrier

The dog is a clinically healthy carrier. The variation is passed on 50% to the offspring, which are also carriers.

cnm/cnm = affected

The variation will be passed on to 100% to the offspring.


  • Carrier animals can be bred to normal animals (N/cnm x N/N). Before using the offspring in breeding, it should be tested whether they are normal or carriers.
  • Mating two carrier animals (N/cnm x N/cnm) should be avoided because there is a 25% chance that the offspring will be affected.
  • Affected animals (cnm/cnm) should be excluded from breeding.


Pelé, M., Tiret, L., Kessler, J.L., Blot, S., Panthier, J.J.: 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 14:1417-27, 2005. Pubmed reference: 15829503. Doi: 10.1093/hmg/ddi151.


Maurer, M., Mary, J., Guillaud, L., Fender, M., Pelé, M., Bilzer, T., Olby, N., Penderis, J., Shelton, G.D., Panthier, J.J., Thibaud, J.L., Barthélémy, 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 7:e46408, 2012. Pubmed reference: 23071563. Doi: 10.1371/journal.pone.0046408.


Further information is available at: Online Mendelian Inheritance in Animals.

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