Form of cone-rod dystrophy (crd) of the Dachshund associated with a mutation in the RPGRIP1 gene. It produces photoreceptor degeneration with initial involvement of cones and progression to blindness. The genetic test identifies carriers. The Dachshund has several PRAs, so this variant (cord1/RPGRIP1) must be distinguished from others. Note: crd4 (C2orf71/PCARE gene) is a Gordon/Irish Setter PRA, not a Dachshund one, and must not be confused with this one.

Described in the Dachshund (long-haired miniature and other varieties). The Dachshund presents multiple PRAs and this variant coexists with others. Frequencies by variety not consolidated (limited data).

- Reduced vision in bright light conditions (early cone involvement)
- Progressive attenuation of retinal vessels
- Progressive tapetal hyperreflectivity
- Night blindness in advanced stages
- Progressive blindness without ocular pain

Cone-rod dystrophy of the Dachshund (cord1) was associated with RPGRIP1 (Mellersh et al. 2006), homologous to human Leber congenital amaurosis. The disease shows incomplete penetrance modulated by a modifier locus (MAP9) (Miyadera et al. 2012; Donner et al. 2024). The crd4 variant (C2orf71/PCARE) belongs to Gordon/Irish Setter (Downs et al. 2013) and not to the Dachshund.

- Test breeding animals before mating
- Do not mate two carriers: 25 % of the litter would be affected
- A carrier can be mated with a clear animal; test the offspring intended for breeding
- Consider panels that include other Dachshund PRAs for complete breed screening

Differential diagnosis with the other PRAs described in the Dachshund and with acquired retinal degenerations. The electroretinogram may show preferential cone involvement. A negative test for crd4 does not exclude other forms of Dachshund PRA.

1. Mellersh CS et al. 2006, la mutación de RPGRIP1 establece la distrofia cono-bastón del Teckel miniatura de pelo largo (PMID 16806805)
2. Miyadera K et al. 2012, GWAS en perros RPGRIP1-/- identifica un locus modificador del inicio de la degeneración (PMID 22193413)
3. Downs LM et al. 2013, PRA de inicio tardío en Gordon e Irish setter asociada a C2orf71 (evidencia de que crd4 no es del Teckel) (PMID 22686255)
4. Donner J et al. 2024, frecuencia de los modificadores RPGRIP1 y MAP9 en 132 razas (PMID 38752391)
5. OMIA:001258 PRA Cord1 (RPGRIP1)