Breeds Affected: Sloughi
Samples Accepted: Blood, Buccal Swabs
Disease Information: Rod-Cone Dystrophy 1a, also known as rcd1a, is a disease in which the cone and rod cells in the retina degenerate, leading to blindness. It is classified as adult-onset, as clinical signs are normally noticed between 2 -3 years of age, and results in complete blindness.
Inheritance Information: Rcd1a 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/rcd1a The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/rcd1a carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
rcd1a/rcd1a The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/rcd1a carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/rcd1a 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/rcd1a x N/rcd1a) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (rcd1a/rcd1a) should not be used for breeding.
Test Information: This mutation test identifies an 8 base pair insertion in the PDE6B gene.
Dekomien, G., Runte, M., Gödde, R., Epplen, J.T.: Generalized progressive retinal atrophy of Sloughi dogs is due to an 8-bp insertion in exon 21 of the PDE6B gene. Cytogenet Cell Genet 90:261-7, 2000. Pubmed reference: 11124530.
Further information is available at the Online Mendelian Inheritance in Animals website.