DNA test - FVIIID (Haemophilia A/Factor VIII deficiency)

Details about the disease

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 the sexes means that to be affected, males only have to inherit one copy of the faulty gene (from its mother), while females must inherit two copies (from both the mother and the father).

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 is it 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 the sexes means that to be affected, males only have to inherit one copy of the faulty gene (from its mother), while females must inherit two copies (from both the mother and the father).

Which laboratories test for this condition?

A lists of laboratories that test for FVIIID (Haemophilia A) can be found below.

Laboratories that send a copy of your dog's results straight to The Kennel Club, so you don't have to.
Laboratories Contact details

Kennel Club CombiBreed (UK)

Available as part of an all-on one health test package for the German Shepherd.

Read more about CombiBreed

Where will your dog's results be published?

DNA test results from these laboratories are sent directly to The Kennel Club and are recorded on to the dog's record in the registration database, and are published:

How are results recorded?

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.

Clear
If your dog is clear they will not have any copies of the abnormal gene associated with FVIIID and will only pass on a normal copy of the gene to any offspring.

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 the abnormal gene on to its offspring.

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 to all of their offspring and so will produce affected male puppies and carrier or affected female puppies, while males will pass the copy of the abnormal gene to their daughters/female puppies but not sons/male 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.
Clear
If your dog is clear they will not have any copies of the abnormal gene associated with FVIIID and will only pass on a normal copy of the gene to any offspring.
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 the abnormal gene on to its offspring.
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 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.

Breeding advice

The decision you make when choosing which dogs to mate must be informed and carefully planned.
If the health status of both sire and dam are known, the likely health status of any puppies produced can be predicted.
Please use the following table to note the outcome of mating a male and female with a known hereditary status:

  Clear male Affected male
Clear female All puppies will be clear

All male puppies will be clear

All female puppies will be carriers

Carrier female

Risk of producing affected male puppies and risk of producing carrier female puppies

Risk of producing affected male puppies and risk of producing carrier female puppies

Affected female

All male puppies will be affected and all female puppies will be carriers 

All male puppies will be affected and all female puppies will be carriers 

If your dog is clear
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.
If your dog is a carrier (females only)
Carrier females should not be mated as there is a risk that they could produce affected male puppies.
If your dog is affected
Affected females should not be used for breeding as all of their male puppies will be affected.

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.
Are clear dogs 100% clear?
Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate, would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease.
Making balanced breeding decisions
As well as considering the implications of a dog’s DNA test results, there are other equally important factors to consider when deciding whether two dogs should be mated together, such as temperament, genetic diversity, conformation, other available health test results, the general health of the dogs etc. Your breeding decisions should always be well balanced and take into consideration the qualities and compatibility of both the sire and dam that you are considering.

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 The Kennel Club's official DNA testing schemes for any dog on The Kennel Club’s Breed Register.