Breeds Affected: Rough and Smooth Collie
Samples Accepted: Blood, Buccal Swabs
Disease Information: Canine Cyclical Neutropenia (CCN) is also known as Grey Collie Syndrome, due to the accompanying coat color dilution. Affected animals have two-week cyclical fluctuations in white blood cell levels, associated with fevers and potentially fatal infections.
Inheritance Information: Canine Cyclic Neutropenia 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 CCN-affected offspring.
N/ccn The dog is a carrier of CCN, and can pass the allele on to approximately 50% of any offspring. If bred to another N/ccn carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
ccn/ccn The dog is affected with CCN. If bred to a normal animal, 100% of the offspring will be carriers. If bred to a N/ccn carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/ccn 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/ccn x N/ccn) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (ccn/ccn) should not be used for breeding.
Test Information: This mutation test identifies a single base pair change in the AP3B1 gene. Animals which have two copies of this allele are affected with CCN, and animals with one copy are clinically-normal carriers.
Benson, K.F., Li, F.Q., Person, R.E., Albani, D., Duan, Z., Wechsler, J., Meade-White, K., Williams, K., Acland, G.M., Niemeyer, G., Lothrop, C.D., Horwitz, M.: Mutations associated with neutropenia in dogs and humans disrupt intracellular transport of neutrophil elastase Nature Genetics 35:90-6, 2003. Pubmed reference: 12897784. Doi: 10.1038/ng1224.
Further information is available at the Online Mendelian Inheritance in Animals website.