Test Detail
Cord1 PRA (Retinal dystrophy)
Ocular · Dog
Molecular test for cone-rod dystrophy 1 (Cord1) progressive retinal atrophy, a hereditary retinal degeneration that initially affects the cones and later the rods and leads to progressive blindness. It affects the ocular system (photoreceptors) and forces the animal to adapt to gradual visual loss. The test reports the clear/carrier/affected status for the corresponding variant.
Incidence
Applicable breeds: Curly coated retriever, Dachshund and English springer spaniel. The carrier frequency varies between breeds (published data for the Dachshund with moderate figures); the figures for the Curly coated retriever and English springer spaniel are more limited and should be verified in the specific literature.
Breeder management
- Genotype breeding animals before mating
- Do not cross carrier×carrier (25 % risk of homozygotes for the variant); carrier×clear produces 0 % homozygotes and 50 % carriers
- Given the incomplete penetrance, a homozygote without clinical signs may still be bred with caution and only with a clear individual, assessing the ocular examination before mating
- After a confirmed clinical case, do not repeat the parental cross and communicate the status to the buyer
- Do not cross carrier×carrier (25 % risk of homozygotes for the variant); carrier×clear produces 0 % homozygotes and 50 % carriers
- Given the incomplete penetrance, a homozygote without clinical signs may still be bred with caution and only with a clear individual, assessing the ocular examination before mating
- After a confirmed clinical case, do not repeat the parental cross and communicate the status to the buyer
Specialist notes
Annual ocular examination (ECVO) as a complement to confirm or rule out the disease in asymptomatic homozygotes, given the risk of incomplete penetrance. Differentiate Cord1 from other PRAs (prcd-PRA, rcd1/rcd2/rcd3) by age of onset and fundus pattern. Cone-rod dystrophy has a different pattern from rod PRA: daytime and colour vision loss before night vision. Verify the exact variant offered by each laboratory.
References
1. Mellersh CS et al. 2006, la mutación canina de RPGRIP1 establece la distrofia de conos y bastones del Dachshund de pelo largo miniatura como homóloga de la enfermedad humana (PMID 16806805)
2. Lhériteau E et al. 2009, el perro deficiente en RPGRIP1 como modelo canino para terapia génica (PMID 19223988)
3. Miyadera K et al. 2012, variaciones genéticas y fenotÃpicas en enfermedades retinianas hereditarias del perro (PMID 22065099)
4. OMIA:001258 PRA Cord1 (RPGRIP1)
2. Lhériteau E et al. 2009, el perro deficiente en RPGRIP1 como modelo canino para terapia génica (PMID 19223988)
3. Miyadera K et al. 2012, variaciones genéticas y fenotÃpicas en enfermedades retinianas hereditarias del perro (PMID 22065099)
4. OMIA:001258 PRA Cord1 (RPGRIP1)