Congenital Myasthenic Syndrome (CMS Dog)
Congenital myasthenic syndrome (CMS) is a neuromuscular disease in which signal transmission between nerve and muscle is disturbed. Affected dogs show muscle weakness and movement disorders and usually have to be euthanised.
The disease occurs in the Labrador Retriever. The inheritance is autosomal recessive.
Symptoms
- Restricted movement up to the inability to move
- Muscle weakness
- Rapid fatigue of the skeletal muscles under exertion
General Information
- Congenital myasthenic syndrome (CMS) is a neuromuscular disease.
- Signal transmission between nerve and muscle is disturbed.
- Puppies are usually euthanised within the first 8 weeks.
Breeds affected
Labrador Retriever
Test Information
This mutation test detects a change of a single base pair in exon 14 of the COLQ gene.
Genotype and Lab Report
Inheritance: autosomal recessive
→ The disease only occurs if both alleles of the gene are affected by the mutation (cms/cms). Dogs that have only one allele with the causative mutation (N/cms) are clinically healthy carriers.
Genotypes:
N/N = genetically normal
The dog has no predisposition for CMS and therefore cannot pass it on to its offspring.
N/cms = a carrier
The dog is a clinically healthy carrier. The variation is passed on 50% to the offspring, which are also carriers.
cms/cms = affected
The dog is affected by CMS and usually does not reach breeding age.
Recommendations
- Carrier animals can be bred to normal animals (N/cms x N/N). Before breeding with the offspring, it should be tested whether they are normal or carriers.
- Mating two carrier animals (N/cms x N/cms) is not recommended, because there is a 25% chance that the offspring will be affected.
Literature
Rinz, C.J., Levine, J., Minor, K.M., Humphries, H.D., Lara, R., Starr-Moss, A.N., Guo, L.T., Williams, D.C., Shelton, G.D., Clark, L.A.: A COLQ Missense Mutation in Labrador Retrievers Having Congenital Myasthenic Syndrome. PLoS One 9:e106425, 2014. Pubmed reference: 25166616. Doi: 10.1371/journal.pone.0106425.
Further information is available at Online Mendelian Inheritance in Animals.