Cone Degeneration (German Shepherd Dog Type)

General Information: Cone Degeneration (German Shepherd Dog Type) is an inherited condition in dogs that leads to the degeneration of cone photoreceptors in the eyes, resulting in day-blindness and photophobia, or light sensitivity, typically starting between 8 to 12 weeks of age. Affected dogs have normal vision in low light because rod photoreceptors, responsible for vision in dim conditions, are not affected. Symptoms include difficulty seeing in bright light and discomfort or pain from exposure to sunlight. Despite these challenges, affected dogs maintain normal night vision throughout their lives. The condition is particularly noted in German Shepherds and related breeds such as the White Shepherd Dog due to the mutation of the CNGA3 gene.

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 of the CNGA3 gene can determine if a dog is a carrier of the mutation responsible for Cone Degeneration (German Shepherd Dog Type). This condition is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene to be affected. Carrier dogs, which have one copy of the mutation, do not show symptoms but can pass the gene to their offspring. When two carriers are bred, there is a 25% chance of producing affected puppies and a 50% chance of producing carrier puppies. To prevent the occurrence of this disease, it is recommended not to breed two carriers. Dogs that test negative for the mutation do not pose a risk of producing affected puppies, ensuring healthier breeding practices and reducing the prevalence of Cone Degeneration in the population.