Congenital Stationary Night Blindness in the Briard breed

An ocular hereditary disease preventable thanks to a DNA test

Congenital Stationary Night Blindness leads to a progressive vision loss. About 5% of briards are carriers of the genetic mutation responsible for the disease. A reliable DNA test can screen stud dogs and brood bitches, in order to adapt matings and avoid birth of affected puppies, and spread of the disease in the breed.

An incapacitating hereditary disease

Congenital stationary Night Blindness leads to a nervous system degeneration. First symptoms like balance disorders, and incapacity to coordinate movments are visible from birth. Puppies unable tostand or to move must be euthanised.

A fairly common disease

About 5% of briards in Europe are carrying of the mutation responsible of Congenital Stationary Night Blindness. A breeder can mate without noticing a male « carrier » and a female « carrier » and produce a litter containing affected puppies.

A dog « carrier » of the mutation will not develop the disease but transmits it to 50% of the puppies. A stallion « carrier » of the mutation which is used a lot for reproduction, spreads the disease through the breed and helps to increase the frequency of the mutation and multiply the number of affected dogs.

A preventable disease

An affected puppy inheritated the mutation from his two parents. Breeders unaware of Congenital Stationary Night Blindness may mate stud dogs and brood bitches carriers of the mutation and, as a consequence, produce affected puppies
A DNA test called CNB, can detect Congenital Stationary Night Blindness with a reliability above 99%

Avoid the birth of affected puppies

In order to secure its kennel and avoid the risk of production of affected puppies, the breeder must screen its breeding dogs thanks to the CNB DNA test.
When acquiring a puppy for breeding or when a stud dog is used for a mating, the breeder verifies the genetic status of the dog for Congenital Stationary Night Blindness asking for the result of the DNA test.

A DNA test easy to perform

The veterinarian performs a simple cheek swab and sends it to the laboratory. The result, delivered within few days, indicates if the tested dog is clear, carrier or affected for the Congenital Stationary Night Blindness.  A genetic certificate displaying the result must be used as a guarantee for a mating or to justify the sale of puppies clear of Congenital Stationary Night Blindness.

The veterinarian who notices early occular issues in a young Briard can process a DNA test to confirm or refute the diagnosis of Congenital Stationary Night Blindness. If the dog is affected, his parents must be screened.

A breeder who knows the genetic status of the dog scan select its breeding dogs, adapt matings, avoid the birth of affected puppies and limit the spread of this occular disease in the breed.

For more information on the CNB DNA test

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