Breeds Affected: Old Danish Pointer
Samples Accepted: Blood, Buccal Swabs
Disease Information: CMS in the Old Danish Pointer can first be diagnosed around 4 months of age by their exercise intolerance: they can typically run for 5-30 minutes at a time, after which they are temporarily paralyzed. The disease does not seem to increase in severity with 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. 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.
– Affected animals should not be bred.
Test Information: This mutation test identifies a single base change in exon 6 of the CHAT gene.
Proschowsky, HF., Flagstad, A., Cirera, S., Joergensen, CB., Fredholm, M.: Identification of a mutation in the CHAT gene of Old Danish Pointing Dogs affected with congenital myasthenic syndrome. J Hered 98:539-43, 2007. Pubmed reference: 17586598. DOI: 10.1093/jhered/esm026.
Further information is available at the Online Mendelian Inheritance in Animals website.