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Congenital Myasthenic Syndrome (CMS) - Golden Retriever Type
| Acronym: | CMS |
| Gene: | COLQ |
| Mutation: | c.880G>A |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Congenital Myasthenic Syndrome (CMS) is a heterogeneous group of genetic disorders causing aberrant neuromuscular transmission. CMSs have previosuly been reported in humans, cats and dogs and are caused by more than 30 mutations that have been identified so far. Canine types of this neuromuscular disorder have been identified in few dog breeds including the Labrador Retriever and Golden Retriever. The clinical signs in affected dogs usually begin at weaning with progressive skeleteal muscle weakness and fatigability. The type of CMS found in Golden Retrievers is a consequence of a point mutation in COLQ gene causing acetylcholinesterase deficiency. Acetylcholinesterase is an enzyme responsible for termination of skeletal muscle contraction by clearing acetylcholine at the neuromuscular junction.
This type of canine CMS found in Golden Retriever is inherited as an autosomal recessive trait, requiring both copies of the mutated gene for the disease to develop. That means dogs with only one mutated gene copy will not develop the disease, but may potentially pass the mutation to their offspring. Early genetic testing can help identify dogs that carry the gene with the specific mutation and prevent their further breeding by proper selection of mating pairs.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Tsai, K. L., Vernau, K. M., Winger, K., Zwueste, D. M., Sturges, B. K., Knipe, M., Williams, D. C., Anderson, K. J., Evans, J. M., Guo, L. T., Clark, L. A., & Shelton, G. D. (2020). Congenital myasthenic syndrome in Golden Retrievers is associated with a novel COLQ mutation. Journal of veterinary internal medicine, 34(1), 258–265. https://doi.org/10.1111/jvim.15667
Mignan, T, Targett, M, Lowrie, M. Classification of myasthenia gravis and congenital myasthenic syndromes in dogs and cats. J Vet Intern Med. 2020; 34: 1707– 1717. https://doi.org/10.1111/jvim.15855