Breeds Affected: Standard Wire-Haired Dachshund
Samples Accepted: Blood, Buccal Swabs
Disease Information: Cone-Rod Dystrophy 3, also known as crd3, 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: Crd3 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/crd3 The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/crd3 carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
crd3/crd3 The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/crd3 carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/crd3 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/crd3 x N/crd3) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (crd3/crd3) should not be used for breeding.
Test Information: This mutation test identifies a deletion in the NPHP4 gene.
Palánová, A., Schröffelová, D., Přibáňová, M., Dvořáková, V., Stratil, A.: Analysis of a deletion in the nephronophthisis 4 gene in different dog breeds. Vet Ophthalmol 17:76-8, 2014. Pubmed reference: 23998563. DOI: 10.1111/vop.12092.
Wiik, AC., Thoresen, SI., Wade, C., Lindblad-Toh, K., Lingaas, F: A population study of a mutation allele associated with cone-rod dystrophy in the standard wire-haired dachshund. Anim Genet 40:572-4, 2009. Pubmed reference: 19392817. DOI: 10.1111/j.1365-2052.2009.01877.x.
Wiik, A.C., Wade, C., Biagi, T., Ropstad, E.O., Bjerkås, E., Lindblad-Toh, K., Lingaas, F.: A deletion in nephronophthisis 4 (NPHP4) is associated with recessive cone-rod dystrophy in standard wire-haired dachshund. Genome Res 18:1415-21, 2008. Pubmed reference: 18687878. DOI: 10.1101/gr.074302.107.
Further information is available at the Online Mendelian Inheritance in Animals website.