Rod-Cone Dysplasia 1a

Rod-Cone Dysplasia (rcd1a) is an eye disorder affecting the development of retinal photoreceptors at the back of the eye, resulting in vision loss.

Key Signs

Night blindness, Loss of vision, Blindness

Age of Onset

1 to 4 yrs

Junior to adult onset


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 rcd1a

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 rcd1a

The first clinical signs of rcd1a include night blindness from rod cell degeneration and can be detected in affected dogs at 2 to 3 years of age. Disease progression may be slow, but eventually the disorder will progress as the cone cells also degrade, impairing day vision, and eventually results in complete blindness.

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 rcd1a mutation can be safely bred with a clear dog with no copies of the rcd1a mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the rcd1a 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 rcd1a mutation could develop due to a different genetic or clinical cause.

Technical Details

Gene PDE6B
Variant Insertion
Chromosome 3
Coordinate Start 91,747,686
Coordinate End 91,747,685

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Dekomien, G., Runte, M., Gödde, R., & Epplen, J. T. (2000). Generalized progressive retinal atrophy of Sloughi dogs is due to an 8-bp insertion in exon 21 of the PDE6B gene. Cytogenetics and Cell Genetics. View the article