Breeds Affected: Irish Setter
Samples Accepted: Blood, Buccal Swabs
Disease Information: Rod-Cone Dystrophy 1, also known as rcd1, is a disease in which the cone and rod cells in the retina degenerate, leading to blindness. Clinical signs can be seen as early as 3 weeks of age, and full blindness results in early adulthood.
Inheritance Information: Rcd1 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/rcd1 The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/rcd1 carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
rcd1/rcd1 The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/rcd1 carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/rcd1 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/rcd1 x N/rcd1) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (rcd1/rcd1) should not be used for breeding.
Test Information: This mutation test identifies a single base pair change in the PDE6B gene.
Suber, M.L., Pittler, S.J., Qin, N., Wright, G.C., Holcombe, V., Lee, R.H., Craft, C.M., Lolley, R.N., Baehr, W., Hurwitz, R.L.: Irish Setter Dogs Affected with Rod/Cone Dysplasia Contain a Nonsense Mutation in the Rod cGMP Phosphodiesterase beta- Subunit Gene Proceedings of the National Academy of Sciences of the United States of America 90:3968-3972, 1993. Pubmed reference: 8387203
Clements, P.J.M., Gregory, C.Y., Petersen-Jones, S.M., Sargan, D.R., Bhattacharya, S.S.: Confirmation of the rod cGMP phosphodiesterase beta subunit (PDE beta) nonsense mutation in affected rcd-1 Irish setters in the UK and development of a diagnostic test Current Eye Research 12:861-866, 1993. Pubmed reference: 8261797
Further information is available at the Online Mendelian Inheritance in Animals website.