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Congenital Stationary Night Blindness      CSNB Test      Code 103

 For breeds: Briard

The OptiGen CSNB test is a DNA-based test that provides, for the first time, a method to unequivocally identify Congenital Stationary Night Blindness, or CSNB, in the Briard. This will control the gene frequency in the breed so as to prevent producing puppies affected with the disease.


Reliable identification of dogs that do not carry disease genes is the key to controlling autosomal recessive diseases. The OptiGen CSNB test enables 100% accurate identification of these dogs. Called "genetically clear," "noncarriers" or, more formally, "homozygous normals," such dogs can pass only the normal gene on to all their pups-which means that none of their pups can ever be affected with CSNB. These "clear" dogs can be bred to any mate, even to a CSNB-affected Briard which may be a desirable breeding prospect for other reasons.


Homozygous means both copies of the gene in your dog are the SAME - both normal or both CSNB. A carrier has one normal and one CSNB gene.

Because the OptiGen CSNB test is a mutation-based gene test, it accurately and specifically identifies normal dogs, carriers (heterozygous dogs) and affecteds. Possible test results are listed in the table below.

Possible results for a Briard using the OptiGen CSNB test
Test Result*Genotype of Briard TestedSignificance For BreedingRisk For Developing CSNB
NNormalCan be bred to any BriardWill never develop CSNB
CCarrierCarrier of CSNBWill never develop CSNB
AAffectedHomozygous for CSNBWill develop CSNB
* This is the result that will be reported when a Briard is tested using the Optigen CSNB test.

The following table highlights all the desirable breedings that will not produce affected pups. These breedings include at least one parent proven "normal" by the OptiGen CSNB test. All other breedings are at risk of producing CSNB-affected pups. However, all dogs can be bred safely. It isn't necessary-or even desirable-to remove any dog from the breeding population. But when choosing pups to retain as potential breeding stock, it is important to select for dogs proven "normal" by the OptiGen CSNB test-and select, when possible, against dogs proven to be carriers. Pups can be tested to distinguish carriers from normals as soon as they are old enough to have a small blood sample collected.

Expected results for breeding strategies using the OptiGen CSNB test
Parent 1
Parent 2     Genotype
NormalAll = Normal1/2 = Normal
1/2 = Carriers
All = Carriers
Carrier1/2 = Normal
1/2 = Carriers
1/4 = Normal
1/2 = Carriers
1/4 = Affected
1/2 = Carriers
1/2 = Affected
AffectedAll = Carriers1/2 = Carriers
1/2 = Affected
All = Affected

The OptiGen CSNB test has been extensively tested in Briards descended from different ancestors of the U.S. Briard breeding population. The test is not currently applicable to other breeds of dogs.

The illustration at the right shows the type of gel patterns our scientists look for in determining the presence or absence of genetic markers in test samples submitted to OptiGen. cell

How you can participate...
The CSNB Test for the Briard is done on a small sample of blood obtained by your veterinarian. This allows the lowest risk of contamination of the sample and added assurance of a match of the sample with the identified dog.

Read and print the instructions on the Ship Sample page. Then fill out the Test Request Form. On-line submission of the Test Request Form lets you be sure accurate information and correct spellings are put in the database. And, when you've completed one Form, a second Test Request Form for another dog or for a litter is easy and saves you time.

A patent application for the technology underlying this test has been filed and OptiGen has obtained an exclusive license for it from Cornell Research Foundation, Inc.

Latest Information

Scientists at the James A. Baker Institute for Animal Health at Cornell University's College of Veterinary Medicine in Ithaca, NY established that Retinal Dystrophy in European Briards and CSNB are the same disorder, and confirmed in purebred Briards in North America that CSNB is caused by a mutation in the RPE65 gene. See the CSNB research report : "Congenital stationary night blindness in the dog: common mutation in the RPE65 gene indicates founder effect".

The patented technology (U.S. Patent No. 6,201,114) underlying this test is under exclusive license to OptiGen, LLC from Cornell Research Foundation, Inc.


Recently, the Board of Directors for the BCA has voted to change the reporting procedure for registration of Briard CSNB results.  Starting January 1, 2011 the BCA has approved that all CSNB results submitted after that date to be sent directly from OptiGen to the Orthopedic Foundation for Animals (OFA).  OptiGen periodically will submit identification and results on all Briards tested to OFA. The OFA fee of $7.50 is added to the test price.

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Tel: 607 257 0301 · Fax: 607 257 0353 · email: or
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