Congenital Stationary Night Blindness

General Information: Congenital Stationary Night Blindness (CSNB) in dogs is characterized by a progressive deterioration of the retina, which is critical for capturing and processing visual information. Symptoms first manifest as a loss of night vision as early as 5 weeks of age, often before any ophthalmologic changes are detectable, which typically become apparent when the dog is between 2 to 3 years old. As the disease progresses, light brown patches appear on the retina, growing and merging until the retina is entirely compromised. Initially, affected dogs may show hesitance to navigate in dim lighting, and over time, their day vision deteriorates as well. This progression can significantly impact the affected dog’s quality of life, as they struggle with increasing visual impairment.

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 RPE65 gene is essential for identifying carriers of Congenital Stationary Night Blindness (CSNB), which is inherited in an autosomal recessive manner. Dogs need to inherit two copies of the mutated gene, one from each parent, to exhibit symptoms of the disease. Carrier dogs possess one copy of the mutated gene but typically do not show any clinical signs of CSNB; however, they can pass the mutation to their offspring. When two carriers are bred, there is a 25% chance that each puppy will be affected by the disease, and a 50% chance that each will be a carrier. To prevent the propagation of this condition, it is recommended not to breed carriers together. Implementing responsible breeding practices through reliable genetic testing can help eliminate this debilitating mutation from the gene pool, ensuring healthier future generations of dogs.