Breeds Affected: Labrador Retriever
Samples Accepted: Blood, Buccal Swabs
Disease Information: Congenital Myasthenic Syndrome (CMS) in the Labrador Retriever is evident in affected pups as early as 4 weeks of age. Affected pups show severe exercise-induced weakness, and are typically humanely euthanized before 8 weeks of age.
Inheritance Information: CMS is autosomal recessive, meaning that animals with two copies of this allele will be affected. Animals with one copy of the gene will be clinically-normal carriers.
The possible genotypes are:
N/N The dog is normal, and cannot produce affected offspring.
N/cms The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/cms carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
cms/cms The dog is affected, but will not live long enough to reproduce. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/cms carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/cms x N/N) without any risk of producing affected offspring. The offspring should be tested before breeding to determine if they are carriers or normal.
– Breeding two carriers (N/cms x N/cms) is not recommended due to the possibility of 25% of the offspring being affected.
Test Information: This mutation test identifies a single base change in exon 14 of the COLQ gene.
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 the Online Mendelian Inheritance in Animals website.