Progressive retinal atrophy / eo-PRA (PDE6B-related) - Spanish Water Dog

What does this test examine?

This genetic test analyses the PDE6B deletion c.2218-2223del for progressive retinal atrophy / early-onset PRA / eo-PRA in the Spanish Water Dog. The variant is located in the PDE6B gene, which is important for rod photoreceptor function.

What does this condition mean?

PRA is a group of inherited retinal diseases in which light-sensitive cells in the eye gradually degenerate. In this early-onset form, affected dogs can develop visual problems at a young age. Night blindness and uncertainty in dim light often appear first, followed by progressive loss of day vision.

Because several PRA forms exist in dogs, this test gives specific information about the tested PDE6B variant.

Inheritance and result

The trait is autosomal recessive. Dogs with two copies are genetically affected; dogs with one copy are carriers and can pass the variant on.

• N/N - the tested deletion was not detected.
• N/del - one copy was detected; the dog is a carrier.
• del/del - two copies were detected; this causes the tested eo-PRA predisposition.

Practical value of this test

The test is valuable because carriers can look completely normal while still passing the variant to offspring.

• Identifies carriers early and reliably.
• Helps avoid carrier-by-carrier matings.
• Supports eye-health selection without removing healthy carriers unnecessarily.
• Gives owners and puppy buyers clear inherited PRA information.
• Helps distinguish eo-PRA from other retinal conditions in the breed.