Canine Congenital Stationary Night Blindness (Discovered in the Beagle)

Canine Congenital Stationary Night Blindness is an inherited retinal disorder which can be associated with different genetic causes. CSNB associated with the LRIT3 variant results in non-progressive vision impairment in dim or absent lighting, known as nyctalopia. Affected dogs can show symptoms starting from birth, although signs can be missed in well lit environments, like urban areas. An affected dog’s retina will often appear normal upon ophthalmic examination, but the dog will have absent rod responses. These individuals typically have an abnormal electroretinogram (ERG) with normal amplitude alpha waves and reduced or absent beta waves, similar to the Schubert-Bornschein form of complete CSNB in humans.

There is no cure for this condition. However, the quality of life for affected dogs is generally good. Environmental modifications can be made during dimly lit situations, such as keeping dogs leashed when walking at dusk or night and the use of yard lights within a fenced area. Owners should be aware that affected dogs will likely need assistance when in dimly lit, unfamiliar surroundings. Keeping the dog's main environment as stable as possible (avoid moving furniture, etc.) and providing night lights may help affected dogs navigate independently during the night.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disorder is autosomal recessive, meaning two copies of the variant are needed for a dog to be at an elevated risk for being diagnosed with the condition. A carrier dog with one copy of the Canine Congenital Stationary Night Blindness variant can be safely bred with a clear dog with no copies of the Canine Congenital Stationary Night Blindness variant. About half of the puppies will have one copy (carriers) and half will have no copies of the variant. Furthermore, a dog with two copies of the Canine Congenital Stationary Night Blindness variant can be safely bred with a clear dog. The resulting puppies will all be carriers. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disorder signs similar to the ones associated with this CSNB variant could develop due to a different genetic or clinical cause.