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von Willebrand disease Type III (vWD III)
Test number: 8233 (this test number replaces the old 80143)
Gene: vWD
Price: £ 48.00 (including VAT)
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Breeds
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Dutch Kooiker (Kooikerhondje )
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Scottish Terrier
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Shetland Sheepdog (Sheltie)
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Kennel Club
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This test is part of the Official UK Kennel Club DNA Testing Scheme in Dutch Kooiker (Kooikerhondje ), and Shetland Sheepdog (Sheltie).
for UK registered dogs, Laboklin can send results of the tests which are part of the Official UK Kennel Club DNA testing scheme to the Kennel Club (KC) to be recorded and published
as part of the Kennel Club scheme. Results will only be recorded and published by the KC if the result report includes the dog’s
microchip or tattoo number along with either the dog’s registered name or registered number. Any test results that do not carry these identifying
features will not be recorded by the Kennel Club.
In order to ensure that test results are sent to the Kennel Club, customers must also sign the declaration section on the order form to give Laboklin permission to do so.
important:
When you sign the declaration, Laboklin will send the results to the KC on your behalf, and you do not need to send them to the KC yourself again to avoid unnecessary duplications.
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The Disease |
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The Disease and its major types
Von Willebrand disease (vWD) is the most common inherited bleeding disorder, which is highly heterogeneous ranging from an asymptomatic laboratory abnormality to a life threatening bleeding. The condition is caused by a quantitative or qualitative deficiency of von Willebrand factor (vWF).
Von Willebrand's disease vWD usually comes in two major types, type I and type III. Type III is a severe bleeding disorder with a high risk of spontaneous bleeding as well as a risk of serious bleeding from trauma and surgery. It is probably best known in Scotch Terriers. The Shetland Sheep Dogs have also the severe type III vWD.
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Description |
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The protein factor assay
The vWD test available in the past has been an assay of von Willebrand factor protein. It is fairly reliable in detecting affected animals, (those with two copies of the defective gene, and at risk for bleeding), because these animals usually have a very low level of the factor. But this test is very unreliable in differentiating gene carriers from clear animals. (Clear dogs are dogs with two copies of the normal gene). Further, many environmental factors influence the protein factor assay. Thus, a dog that tested in the 'normal' range one year could have a low value in the (carrier) range the next year. As a result breeders have not had much success breeding out this disease, which was frustrating to them.
The mutation-based test and its advantages
The genetic defect leading to the disease has been identified. By DNA testing the responsible mutation can be shown directly. This DNA test can be done at any age and unambiguously classify dogs for the rest of their lives into affected, carrier, and clear animals. With this test the breeder can rapidly eliminate the vWD disease gene from the breed. If a particularly valuable dog turns out to be a carrier, it can be bred to a clear animal, and non-carrier puppies saved for the next round of breeding.
The frequency of carriers was estimated to be that about 11% of Shetland Sheep Dogs are carriers of the type III vWD mutation. This is a significant health burden, and it would be good to get rid of this disease gene by using the DNA test. It should be emphasised that carriers will be clinically normal, and can be used as pets. As said above, if a carrier has excellent breed characteristics, it can be bred to a clear animal, and only clear animals among the progeny be used for further breeding.
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Trait of Inheritance |
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vWD Type III is inherited in an autosomal recessive trait. This means that a dog can be genetically clear (also called homozygous normal), a carrier (also called heterozygous) or affected concerning vWD type III. Especially the carriers can spread the diseased gene in the population. Therefore reliable information of dogs that do not carry disease genes is the key to controlling this disease.
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Inheritance : AUTOSOMAL
RECESSIVE
trait
Sire
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Dam
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Offspring
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clear
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clear
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100% clear
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clear
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carrier
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50% clear + 50%
carriers
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clear
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affected
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100% carriers
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carrier
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clear
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50% clear + 50%
carriers
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carrier
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carrier
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25% clear + 25% affected
+ 50% carriers
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carrier
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affected
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50% carriers + 50%
affected
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affected
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clear
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100% carriers
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affected
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carrier
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50% carriers + 50%
affected
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affected
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affected
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100% affected
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Clear
Genotype: N / N [ Homozygous normal ]
The dog is noncarrier of the mutant gene.
It is very unlikely that the dog will develop von Willebrand disease Type III (vWD III). The dog will never pass the mutation to its offspring, and therefore it can be bred to any other dog.
Carrier
Genotype: N / vWD [ Heterozygous ]
The dog carries one copy of the mutant gene and one
copy of the normal gene.
It is very unlikely that the dog will develop von Willebrand disease Type III (vWD III) but since it carries the mutant gene, it can pass it on to its offspring with the probability of 50%. Carriers should only be bred to clear dogs. Avoid breeding carrier to carrier because 25% of their offspring is expected to be affected (see table above)
Affected
Genotype: vWD / vWD [ Homozygous mutant ]
The dog carries two copies of the mutant gene and
therefore it will pass the mutant gene to its entire offspring.
The dog is likely to develop von Willebrand disease Type III (vWD III) and will pass the mutant gene to its entire offspring
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Price
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£ 48.00 (including VAT)
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