Achromatopsia 3 / day blindness (CNGB3 deletion) - Dog

What does this test examine?

This genetic test examines a complete deletion of the CNGB3 gene. This variant is known in achromatopsia 3, also called cone degeneration, hemeralopia or day blindness.

What does this mean for the dog?

CNGB3 is important for cone function in the retina. Affected dogs can have clear problems in bright light: day blindness, light sensitivity, reduced colour vision and reduced visual acuity. Vision in dim light is often much better preserved because the cone system is mainly affected.

Practical value of this test

• The test helps distinguish clear dogs, carriers and genetically affected dogs.
• Breeders can use carriers responsibly without unintentionally producing affected puppies.
• In young dogs with light sensitivity or poor daytime vision, the result can provide useful clarification.

The condition is inherited as an autosomal recessive trait. A dog with two copies of the deletion develops the disorder; a carrier usually has normal vision but can pass the variant to offspring.