Progressive Retinal Atrophy (PRA)
This is a hereditary disorder where the retina degenerates, eventually causing blindness. There are several identified forms of PRA in other breeds, but the specific form which occurs in Cardigans is the rcd3 type and is known to occur in several breeds.
Other eye disorders identified in Cardigans involving the retina include cPRA (centralized PRA), which affects the central area of the retina, leaving the periferal vision intact. Current research indicates this problem is more likely to be connected to Vitamin E deficiency rather than genetic in origin. There are also Retinal Dysplasias (folds or geographic type) which are patterned detachments of the retina that typically occur during development and can be identified as early as 6 wks. Genetic markers for this form of retinal dysplasia are still unknown.
Other issues which can result in blindness include cataracts and glaucoma.
Symptoms: Gradual loss of vision, bumping into furniture or other objects, dilated pupils in some cases. Dogs often adjust well to blindness, so symptoms may not be apparent until the dog is in an unfamiliar location.
Treatment Options: Currently there are no treatment options for PRA. Fortunately is it painless and non-lethal, but can reduce quality of life if the dog has difficulty adjusting to loss of vision. For breeders, the best treatment is prevention by testing breeding stock and avoiding mating carriers.
Known Mode of Inheritance: Autosomal Recessive. Identified as the rcd3 (pde6A) marker in Cardigans.
Age of onset: < 1
- Cardigan: yes
- Pembroke: yes
- Other Breeds: yes
Incidence in Cardigans: Currently very low due to breeder participation in testing and open registry. Currently all Cardigans listed in the OFA registry are PRA clear. Some carriers are still present in the breed and breeders who have identified carriers in their lines have taken steps to test and breed responsibly, so there is a bright future for Cardigans as a breed eventually becoming clear of rcd3 PRA.
The Cardigan community owes a debt to Dr. Simon Peterson-Jones, whose research led to the diagnostic test identifying dogs carrying the gene.
- Cardigans: yes
- Other breeds: yes
- Active?: yes
Registry: yes, the OFA will register PRA tested cardigans. Submit copies of the DNA registration form and the rcd3 test results from one of the four accepted testing facilities: Genetic Technologies (Australia), HealthGene (Canada), OptiGen, VetGen(USA).
- Links to register: Instructions are included on the OFA DNA registration form (see above link).
- Optigen notice about registering with OFA
Tests Available: yes, see above links to approved testing facilities for OFA registry.
- Alternate Sources for PRA testing: VetNostic PRA testing NOTE: The VetNostic PRA test is not recognised for registry by the OFA.
- Optigen Research Samples Needed for PRA and Cataracts.
Published papers and Articles:
- cGMP phosphodiesterase-alpha mutation causes progressive retinal atrophy in the Cardigan Welsh corgi dog
- Development and use of a polymerase chain reaction-based diagnostic test for the causal mutation of progressive retinal atrophy in Cardigan Welsh Corgis
- An improved DNA-based test for detection of the codon 616 mutation in the alpha cyclic GMP phosphodiesterase gene that causes progressive retinal atrophy in the Cardigan Welsh Corgi.