The Disease
The Briard dog is affected with a retinal disorder characterized by congenital night blindness with various degrees of visual impairment under phototopic illumination. Vision in affected dogs ranges from normal day vision to profound day blindness. Along with the visual impairment, affected dogs have an abnormal electroretinogram (ERG).

The Trait of Inheritance
CSNB is inherited in an autosomal recessive trait. This means that a Briard dog can be genetically clear (also called homozygous normal), a carrier (also called heterozygous) or affected concerning the night blindness. Especially the carriers can spread the diseased gene in the population. Therefore reliable information of dogs that do not carry disease genes is the key to controlling this disease. 

The mutation-based gene test and its advantages
The genetic defect leading to CSNB in the Briard has been identified. By DNA testing the responsible mutation can be shown directly. This method provides a very high test accuracy and can be done at any age. It offers the possibility to distinguish not only between affected and normal / unaffected dogs but also to identify clinically healthy carriers. This is an essential information for controlling the disease in the breed as carriers are able to spread the disease in the population but can not be identified by means of common laboratory diagnostic. If a particularly valuable dog turns out to be a carrier, it can be bred to a clear animal, and non-carrier puppies saved for the next round of breeding.

Requirements
The test is performed out of  EDTA whole blood (0.5 ml). Testing is performed a few times per week at Laboklin. The results are due about one week after arrival of the sample in our laboratory.