Cone Degeneration (German Shorthaired Pointer Type)

General Information: Cone Degeneration (German Shorthaired Pointer Type) is a genetic eye disease that affects dogs, causing the degeneration of cone photoreceptors, which are responsible for vision in bright light. Symptoms typically begin to appear between 8 and 12 weeks of age, resulting in day-blindness (inability to see in bright light) and photophobia (sensitivity to light). Despite these issues, affected dogs retain normal vision in low light, as the rod photoreceptors, which are responsible for night vision, are not affected. An eye examination of affected dogs will show that the inner eye structures appear normal. An Electroretinogram (ERG) can detect normal cone cell function before six weeks of age, but this function becomes abnormal between 6 and 12 weeks and is completely absent in adult dogs, indicating a total loss of cone cells. This condition significantly impacts the dogs’ ability to see in bright environments while allowing them to function normally in low light conditions throughout their lives.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for the CNGB3 gene is crucial for identifying carriers and dogs affected by Cone Degeneration (German Shorthaired Pointer Type). This disorder is inherited in an autosomal recessive manner, meaning that a dog must inherit two copies of the mutated gene, one from each parent, to develop the condition. Carrier dogs, which possess one normal and one mutated gene, do not exhibit symptoms but can pass the mutation to their offspring. Breeding two carriers is risky, as each puppy has a 25% chance of developing the disease and a 50% chance of being a carrier. Reliable genetic testing for the CNGB3 mutation allows breeders to make informed decisions, avoiding the pairing of two carriers to prevent the production of affected puppies. This approach helps eliminate the mutation from breeding lines and ensures the health and well-being of future generations. It is important to note that while a clear result for the CNGB3 gene reduces the risk of Cone Degeneration, there may be other genetic causes for similar conditions. Comprehensive genetic screening is vital to maintain the overall eye health and quality of life for dogs susceptible to this disorder.