Help us fight disease and injury in animals

Congenital Stationary Night Blindness in Briards

Congenital Stationary Night Blindness (csnb) in Briards, also called hereditary retinal dystrophy, is an inherited disease caused by a defect in the gene RPE65. The symptoms include night blindness and a loss of vision in daylight that can vary between individual dogs. The disease shows an autosomal recessive mode of inheritance; therefore. two copies of the defective gene, one inherited from each parent, have to be present for a dog to be affected by the disease. Individuals with one copy of the defective gene and one copy of the normal gene - called carriers - show no symptoms but can pass the defective gene onto their offspring. When two apparently healthy carriers are crossed, 25% (on average) of the offspring will be affected by the disease with a further 50% themselves being carriers.
The genetic defect underlying this condition was first identified in the Swedish population of Briards as a deletion of a small segment of the DNA within the gene for RPE65, a protein involved in the biochemistry of vision. The same defect was subsequently shown to underlie the disease in the US population and research at the Animal Health Trust has confirmed that the same defect causes csnb in UK Briards. The Animal Health Trust is now offering a DNA test for this disease distinguishing affected, carrier and normal individuals. The test directly probes directly the DNA of the RPE65 gene and provides definitive information on the genetic status of this disease, giving breeders the information to eradicate the disease from their lines.

The test diagnoses Briards affected with this disease but can also detect those dogs which are carriers, showing no symptoms of the disease but able to produce affected pups. It is important to eliminate such carriers from a breeding population since they represent a hidden reservoir of the disease that can produce affected dogs at any time.

We have reduced the price of this test  from  £56 to £45 (including VAT). and can now offer a fast-track service for recent litters;   results for these litters will be available by e-mail within 7 working days of receipt of the sample. This offer is initially for a limited period of six months only from 1/2/2011.

Samples submitted should be cheek swabs (a non-invasive sampling method) obtained from the Animal Health Trust. Samples should be sent together with a completed DNA Testing form for each sample to Genetic Services, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU.  The price of the test is £45, which includes both VAT and the cost of the mouth swab sampling kit.

Kits for taking cheek swabs are available via our webshop.

Further information can be obtained by e-mailing dnatesting@aht.org.uk or swabrequest@aht.org.uk, or by phoning +44 (0)1638 555621