Quick Summary
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Phenotype: Cats affected with this rare form of early-onset blindness have retarded development and degeneration of photoreceptor cells, which leads to blindness by 7 weeks of age.
Mode of Inheritance: Autosomal dominant
Alleles: N = Normal, Rdy = Progressive retinal atrophy (CRX mutation-associated)
Breeds appropriate for testing: Abyssinian, Somali
Explanation of Results:
- Cats with N/N genotype will not have CRX/Rdy progressive retinal atrophy and cannot transmit this progressive retinal atrophy variant to their offspring.
- Cats with N/Rdy genotype will have CRX/Rdy progressive retinal atrophy, an untreatable condition leading to early-onset blindness. They will transmit this progressive retinal atrophy variant to 50% of their offspring. Matings between two N/Rdy cats are predicted to produce 75% kittens affected by this CRX/Rdy form of progressive retinal atrophy.
- Cats with Rdy/Rdy genotype will have CRX/Rdy progressive retinal atrophy, an untreatable condition leading to early-onset blindness. They will transmit this progressive retinal atrophy variant to all of their offspring.
$44 one test per animal
Also available as part of the following packages:
- $66 this test + PRA rdAc test OR PK Deficiency Test (Abyssinian, Somali, and domestic shorthair)
- $88 this test + PRA rdAc test + PK Deficiency Test (Abyssinian, Somali, and domestic shorthair)
Sample Collection:
Cat DNA tests are carried out using cells collected from your cat's cheeks and gums using household cotton swabs.
The cat DNA submission form with instructions and a place to tape the cotton swabs is sent to you via email after you place an order, and can be printed from your home computer. Test kits are not mailed.
Step-By-Step Instructions:
1.
Purchase regular household cotton swabs for cat DNA collection (the cotton swabs can be purchased at a pharmacy or drug store)
2.
Use both ends of the two cotton swabs for a total of four swabs.
3.
Collect the DNA sample by swabbing the cheek and gums of the cat. Wave the swab in the air for 10-15 seconds to air dry it before attaching it to the submission form. We recommend swabbing different areas of the cat's cheeks.
4.
After swabbing the cheek and gums, tape the cotton swabs to the bar-coded submission form printed from your MyVGL account.
A form of blindness called “rod cone dysplasia”, or “Rdy” has been identified in Abyssinian and Somali cats. This progressive retinal atrophy differs from the "rdAc" (CEP290 mutation) progressive retinal atrophy. The mutation underlying "Rdy" is a single base pair deletion in a different gene, CRX, which results in a defective protein that is critical for eye development. Cats carrying one copy of this mutation have retarded development and degeneration of photoreceptor cells, which leads to early-onset blindness by 7 weeks of age. Current information suggests that the “Rdy” mutation is restricted to the Abyssinian and Somali breeds. The “Rdy” mutation is inherited as a dominant trait: cats that have one or two copies of the mutation will be affected. The Rdy mutation is rare.
To assist owners and breeders in identifying affected and carrier cats, the VGL offers DNA tests for the two mutations known to cause the two different forms of PRA in cats - rdAc (CEP290) and Rdy (CRX). Breeders can use these tests as tools to avoid breeding two carriers of rdAc which would produce 25% affected offspring, or to test for the presence of “Rdy” in the CRX gene of suspected affected cats.
Since both forms of blindness are found in the Abyssinian breed, all associated breeds may have a concern for these diseases. A novel form of blindness occurs in the Bengal cat, and a separate causative mutation has been identified (a genetic test for the Bengal-specific PRA is available here). However, since Bengal cats have had Abyssinian breedings in their ancestry, genetic testing for rdAc and Rdy may also be warranted in some Bengal lines.