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A DNA test for Congenital Stationary Night Blindness (CSNB)
What is CSNB?
A DNA test for CSNB
Up to now CSNB has only been reported in the Briard. The disorder is inherited as an
autosomal recessive trait. In other words, affected animals have two mutant genes, one
inherited from each parent. Carriers have only one mutant gene and do not show clinical
signs.
Applying the DNA test allows breeders to classify their potential breeding animals at a
young age as genetically healthy ("clear"), "carrier" or "affected" in order to select
effectively against the genetic disorder.
The CSNB DNA test yields three possible outcomes:
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Your dog is clear (and has two healthy alleles: CSNB/CSNB),
it will not suffer from congenital night blindness and, just as important,
it will not pass on the defect (the defective allele) to the next generation.
-
Your dog is a carrier (and has one healthy allele and one defective
one: CSNB/csnb), it will not suffer from CSNB but it
will pass on the defective allele to half of its offspring.
-
Your dog is affected (and has two defective alleles: csnb/csnb), it
will pass on the defective allele to all of its offspring in the next generation
and it will be expected to experience the disadvantages of night blindness. So
it is one of the animals that will suffer from Congenital Stationary Night
Blindness (CSNB).
Breeds at risk
Breeding policy
Testing for CSNB
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