Glossary

Screening Scheme Description

DNA test - FVIIID
Haemophilia A/Factor VIII Deficiency

Details about the diseases

Haemophilia A is a bleeding disorder caused by the dog lacking a protein (coagulation factor VIII) which is needed for healthy blood clotting.

Clinical signs

Affected dogs may have a range of effects, including bruising easily, nosebleeds, longer than usual periods of bleeding if cut and stiffness, which may be a sign of damage to muscles or joints.

In severe cases, bleeding can be life threatening, but most dogs do live a normal lifespan.

How it is inherited

This condition is linked to a faulty gene found on one of the chromosomes that determines the dog’s sex.

Male dogs only have one copy of this sex chromosome, while females have two copies. The differences between sexes means that to be affected, males only have to inherit one copy of faulty gene (from its mother), while females must inherit two copies (from both the mother and the father).

Female dogs that have been tested for this condition can be described as either: clear, carrier or affected.

Male dogs that have been tested for this condition can be described as either clear or affected.

Results and breeding advice: Clear

If your dog is clear they will not have any copies of the abnormal gene associated with the condition they has been tested for. Your dog will not be clinically affected by the disorder and will only pass on a normal copy of the gene to any offspring.

Clear male dogs should only be mated to clear females, while clear females can be mated to either clear males or affected males. All other matings may produce affected male puppies and so should not be carried out.

Mating clear females to affected males should only be carried out if it does not pose a risk to the males welfare. Any female puppies produced from this mating will be a carrier and should not be used for breeding, but may be good for a pet home, providing appropriate breeding restrictions are placed in any puppy buyer contracts.

Results and breeding advice: Carrier (females only)

If the female dog is a carrier they will have one copy of the normal gene and one copy of the abnormal gene associated with haemophilia A. The dog will not be clinically affected by the disorder, but may pass one copy of abnormal gene on to its offspring.

Carrier females should not be mated as there is a risk that they could produce affected male puppies.

Results and breeding advice: Affected

Male dogs will have one copy of the abnormal gene associated with haemophilia A, while the females will have two copies. The dog will be clinically affected by the disorder. If bred from, females will pass on a copy of this abnormal gene, while males will have a 50% chance of passing on the gene, but only to female puppies. It is advised that you speak to your vet about the results of this test to determine how this condition may affect your dog.

Affected females should not be used for breeding as there is a risk of producing affected male puppies. Affected male dogs should only be bred to clear females and only if the mating does not pose a risk to his welfare. Any female puppies produced from this mating will be a carrier and

should not be used for breeding, but may be good for a pet home, providing appropriate breeding restrictions are placed in any puppy buyer contracts.

Which laboratories test for this condition?

A list of laboratories and DNA tests can be found at the following link www.thekennelclub.org.uk/health/for-breeders/dna-testing-simple-inherited-disorders/worldwide-dna-tests/

How to find out if a potential mate has been DNA tested

The Kennel Club’s “Health Test Results Finder” allows you to find the results of DNA tests carried out as part of official Kennel Club DNA testing schemes for any dog on the Kennel Club’s breed register. To access this free health tool, please follow this link http://bit.ly/1jyCFnc.

 


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