FACTOR VII DEFICIENCY
Factor VII is a coagulation factor involved in blood-clotting. A mutation in Factor VII has recently been discovered by researchers in the laboratory of Professor Urs Giger at the University of Pennsylvania which inhibits blood clotting in Scottish Deerhounds and Beagles. This disorder causes mild to moderate levels of bleeding. The disease is inherited as an autosomal recessive trait, and carriers (dogs with one copy of the normal form of the gene and one copy of the mutated form of the gene) do not show symptoms, although laboratory studies have suggested that they may have some decrease in clotting activity.
Since carriers are free of the disease symptoms, they can be freely crossed with dogs which have been DNA tested clear of the mutation, without producing any clinically affected pups. The litters produced (averaged over a sufficiently large number of pups) will be split 50:50 between genetically clear pups and carriers. The genetic status of any pups (clear or carrier) to be used for breeding can be readily identified by further DNA testing.
Using DNA testing, breeders have the opportunity to effectively eradicate the disease from the breed population. When both sire and dam have been DNA tested clear of the mutation, then all the pups from that mating must be clear by heredity.
The test is available now and information on submitting samples is given below.
Breeders will be sent results identifying their dog as belonging to one of three categories:
This dog is CLEAR of FACTOR VII DEFICIENCY:
This dog has 2 copies of the normal gene and will neither develop FACTOR VII DEFICIENCY nor pass this mutation to its offspring.
This dog is a CARRIER of FACTOR VII DEFICIENCY:
This dog has one copy of the normal gene and one copy of the mutation associated with this disease. It will not develop FACTOR VII DEFICIENCY but will, if bred from, pass mutation to 50% of its offspring, on average.
This dog is affected with FACTOR VII DEFICIENCY:
This dog has 2 copies of the mutation associated with this disease.
Samples submitted should be cheek swabs (a non-invasive sampling method) obtainable from the Animal Health Trust. Samples should be sent together with a completed DNA Testing form and payment for each sample to Genetic Services, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU. Kits for taking cheek swabs are available by phoning 01638 555621 or via e-mail to swab.request@aht.org.uk. Further information can be obtained by e-mailing dna.testing@aht.org.uk. A list of prices can be found on our web-site www.aht.org.uk
DNA testing forms can be downloaded by clicking here.
The research identifying the gene causing this disorder is described in:
Callan,M.B., Aljamali,M.N., Margaritis,P., Griot-Wenk,M.E., Pollack,E.S., Werner,P., Giger,U. and High,K.A. (2006) A novel missense mutation responsible for factor VII deficiency in research Beagle colonies. J. Thromb. Haemost. 4 2616-2622