Rod-Cone Dysplasia 1
Rod-Cone Dysplasia 1 (rcd1) is an inherited eye disorder that results in blindness, and was identified in Irish Setters and Irish Red and White Setters.
Key Signs
Night blindness, Loss of vision, Blindness
Age of Onset
0 to 2 yrs
Juvenile onset
Inheritance
Autosomal Recessive
For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.
Likelihood of the Condition
High likelihood
At risk dogs are highly likely to show signs of this disease in their lifetime.
What to Do
Here’s how to care for a dog with rcd1
Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.
For Veterinarians
Here’s what a vet needs to know about rcd1
The first clinical signs of rcd1 include night blindness from rod cell degeneration which begin by 6 to 8 weeks of age. The disorder will progress as the cone cells also degrade, impairing day vision, and eventually the disorder will result in complete blindness. rcd1 is fast progressing, causing blindness by one year of age.
A blind dog tends to adapt well to the loss of vision. However, some dogs may exhibit a tentativeness when introduced to unknown environments because their vision is compromised. Occasionally, they may react abruptly (snapping) if they are startled so caution and use of verbal queues should be taken when handling a blind dog. Caretakers should take precautions to protect the blind dog from threats it cannot detect (ex. cliffs, sharp points on furniture, moving vehicles).
For Breeders
Planning to breed a dog with this genetic variant?
There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.
This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the rcd1 mutation can be safely bred with a clear dog with no copies of the rcd1 mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the rcd1 mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the rcd1 mutation could develop due to a different genetic or clinical cause.
Technical Details
| Gene | PDE6B |
|---|---|
| Variant | G>A |
| Chromosome | 3 |
| Coordinate | 91,747,714 |
All coordinates reference CanFam3.1
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References & Credit
Credit to our scientific colleagues:
Suber, M. L., Pittler, S. J., Qin, N., Wright, G. C., Holcombe, V., Lee, R. H., … Hurwitz, R. L. (1993). Irish setter dogs affected with rod/cone dysplasia contain a nonsense mutation in the rod cGMP phosphodiesterase β-subunit gene. Proceedings of the National Academy of Sciences of the United States of America, 90(9), 3968–3972. View the article
