Breeds Affected: German Shorthaired Pointer
Samples Accepted: Blood, Buccal Swabs
Disease Information: Achromatopsia (cone Degeneration; cd) is caused by a degeneration of cone cells just after the completion of retinal development, and is usually diagnosed between 8-12 weeks of age. Affected pups have day-blindness in bright light, but normal vision in dim light. The condition is not obvious on ophthalmoscopic examination, and vision does not deteriorate further with time.
Inheritance Information: Achromatopsia 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/cd The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/cd carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
cd/cd The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to a N/cd carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/cd 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/cd x N/cd) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (cd/cd) should not be used for breeding.
Test Information: This mutation test identifies a single base change in exon 6 of the CNGB3 gene.
Sidjanin, D.J., Lowe, J.K., McElwee, J.L., Milne, B.S., Phippen, T.M., Sargan, D.R., Aguirre, G.D., Acland, G.M., Ostrander, E.A.: Canine CNGB3 mutations establish cone degeneration as orthologous to the human achromatopsia locus ACHM3 Human Molecular Genetics 11:1823-33, 2002. Pubmed reference: 12140185.
Miyadera, K., Acland, G.M., Aguirre, G.D.: Genetic and phenotypic variations of inherited retinal diseases in dogs: the power of within- and across-breed studies. Mamm Genome 23:40-61, 2012. Pubmed reference: 22065099. Doi: 10.1007/s00335-011-9361-3.
Further information is available at the Online Mendelian Inheritance in Animals website.