Breeds Affected: Old English Sheepdogs (Bobtails)
Samples Accepted: Blood, Buccal Swabs
Disease Information: Primary ciliary dyskinesia (PCD) causes defects in the cilia of the respiratory tract, leading to frequent infections of the upper and lower respiratory tract. Sperm flagella are also affected, leading to reduced fertility in males, and defects in cilia that determine left-right asymmetry during development leads to situs inversus in about 50% of affected individuals.
Inheritance Information: PCD 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/pcd The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/pcd carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
pcd/pcd The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/pcd carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/pcd 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/pcd x N/pcd) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (pcd/pcd) should not be used for breeding.
Test Information: This mutation test identifies a single base pair change in exon 3 of the CCDC39 gene.
Merveille, A.C., Davis, E.E., Becker-Heck, A., Legendre, M., Amirav, I., Bataille, G., Belmont, J., Beydon, N., Billen, F., Clément, A., Clercx, C., Coste, A., Crosbie, R., de Blic, J., Deleuze, S., Duquesnoy, P., Escalier, D., Escudier, E., Fliegauf, M., Horvath, J., Hill, K., Jorissen, M., Just, J., Kispert, A., Lathrop, M., Loges, N.T., Marthin, J.K., Momozawa, Y., Montantin, G., Nielsen, K.G., Olbrich, H., Papon, J.F., Rayet, I., Roger, G., Schmidts, M., Tenreiro, H., Towbin, J.A., Zelenika, D., Zentgraf, H., Georges, M., Lequarré, A.S., Katsanis, N., Omran, H., Amselem, S.: CCDC39 is required for assembly of inner dynein arms and the dynein regulatory complex and for normal ciliary motility in humans and dogs. Nat Genet 43:72-8, 2011. Pubmed reference: 21131972. Doi: 10.1038/ng.726.
Further information is available at the Online Mendelian Inheritance in Animals website.