Progressive retinal atrophy - Cord 1

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Progressive retinal atrophy (PRA) Cone-rod dystrophy 1 (Cord 1) is an autosomal-recessive genetic disease characterised by degeneration of the photoreceptor cells in the retina, eventually leading to complete blindness[1].

This genetic disease has been reported in the English Springer Spaniel and Dachshund breeds[2].

This form of PRA has been documented in scientific literature and was believed to have an age of onset of around 2-10 years with the average age of diagnosis of the Miniature Long-haired Dachshunds in one study was 4.98 years. It is possible that the factors causing this variation could delay the onset of obvious clinical signs beyond the lifespan of the dog, so owners may never see behavioural changes and never recognise that their dog has a problem. However, the dog will still be genetically-affected by the disease and have two copies of the cord1 mutation.

Most PRA cases with Cord 1 mutation are clinically indistinguishable from other forms of PRA.

This form of PRA has an age of onset of around 2 - 10 years with the average age of diagnosis, and many may be subclinically affected.

A breed-specific PCR test is available for testing for this condition[3].

There is no known treatment for this condition and severely affected individual dogs often remain blind.

References

  1. Petit L et al (2012) Restoration of Vision in the pde6β-deficient Dog, a Large Animal Model of Rod-cone Dystrophy. Mol Ther 20(11):2019-2030
  2. Mellersh CS et al (2006) Canine RPGRIP1 mutation establishes cone-rod dystrophy in miniature longhaired dachshunds as a homologue of human Leber congenital amaurosis. Genomics 88(3):293-301
  3. Petersen-Jones SM & Zhu FX (2000) Development and use of a polymerase chain reaction-based diagnostic test for the causal mutation of progressive retinal atrophy in Cardigan Welsh Corgis. Am J Vet Res 61(7):844-846