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Rod Cone Dysplasia Type 3      rcd3-PRA       Test  Code 313

Test Pricing

For breeds: Cardigan Welsh Corgi, Chinese Crested & Pomeranian

Progressive Retinal Atrophy (PRA), a group of inherited blinding canine diseases, is seen in many pure breeds, although the exact genetic cause is known for only a few.  A specific form of PRA, Rod Cone Dysplasia Type 3 in Corgis and some other breeds, is of early onset with signs of retinal abnormality and vision loss already by one year of age. The Corgi form of PRA is called rcd3, that is, the third PRA form with rod-cone degeneration. Rod and cone refer to the shapes of cells in the retina that respond to light, but are progressively degenerating when affected with this disease. Corgi PRA is caused by a mutation in the gene called PDE6A whose normal state is essential for normal vision. Within a set of nearly 600 dogs, a carrier rate of about 8.5% was reported.

Breeding recommendations:

Although PRA can't be treated, it can be prevented. The key to preventing autosomal recessive diseases lies in identifying dogs that do not carry the defective genes. The mutation based rcd3-PRA  test unequivocally and reliably identifies normal dogs. Called genetically clear/normal, such dogs can pass only the normal gene on to all their pups. This means that none of their pups can ever be affected with this form of PRA. These clear dogs can be bred to any mate, even to PRA-affected dogs that may be desirable breeding prospects for other reasons.

The test also identifies carriers and affected dogs with 100% accuracy. But while a normal dog may be bred to any other dog, carriers and affecteds must be bred only to normal dogs. Desirable breedings include at least one parent proven "normal" by the DNA-based rcd3-PRA test, as shown in the shaded areas of the following table. Breeding untested dogs or breeding two carrier dogs puts you at risk of producing PRA-affected pups.

Expected results of breeding strategies using OptiGen mutation tests for inherited recessive diseases
Parent 1
Genotype
Parent 2     Genotype
NormalCarrierAffected
NormalAll = Normal1/2 = Normal
1/2 = Carriers
All = Carriers
Carrier1/2 = Normal
1/2 = Carriers
1/4 = Normal
1/2 = Carriers
1/4 = Affected
1/2 = Carriers
1/2 = Affected
AffectedAll = Carriers1/2 = Carriers
1/2 = Affected
All = Affected
The “recessive” table shows the expected results from breeding dogs of each genetic status. It is important never to breed two carrier dogs, because on average 25% of the pups could be affected. One parent should always be clear/normal for PRA.

Please follow the instructions at the link "Ship Sample" and submit the information at "Request Test".

For more information on this breed and the disease, go to: Cardigan Welsh Corgi Website

References:

1. Petersen-Jones SM, Entz DD, Sargan DR. cGMP phosphodiesterase-alpha mutation causes progressive retinal atrophy in the Cardigan Welsh corgi dog. Invest Ophthalmol Vis Sci. 1999 Jul; 40(8):1637-44.

2. Petersen-Jones SM, Zhu FX. Development and use of a polymerase chain reaction-based diagnostic test for the causal mutation of progressive retinal atrophy in Cardigan Welsh Corgis. 2000. American Journal of Veterinary Research 617):844-846.


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Tel: 607 257 0301 · Fax: 607 257 0353 · email: genetest@optigen.com or optigen@clarityconnect.com
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