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Haemophilia A (factor VIII deficiency / F8)
Test number: 8689 (this test number replaces the old 8222D)
Gene: FVIII
Price: £ 48.00 (including VAT)
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Breeds
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Boxer
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German Shepherd
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Labrador Retriever
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Old English Sheepdog (Bobtail)
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Rhodesian Ridgeback
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The Disease |
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Haemophilia A is one of the most important inherited disorders of haemostasis in Havanese Dogs. The underlying pathomechanism of Haemophilia A is a lack or decreased activity of factor VIII that plays a critical role in the coagulation cascade. Affected dogs present with hemorrhage that can vary from mild to severe depending on the degree of the disease. The clinical signs include haematomas of large sizes, bleeding of the nose, skin, muscles and joints. If the disease is severe and no precautions are taken, affected dogs can bleed to death after surgery or injury.
In cooperation with Prof. Dr. Mischke (Tierärztliche Hochschule Hannover) LABOKLIN was able to identify a SINE insert in exon 14 of the factor VIII gene that is responsible for the lack of active factor VIII protein in Havanese Dogs.
Haemophilia A is a sex-linked disorder (x-chromosomal recessive). Male dogs express the disease when they have one mutated x-chromosome. The mutated x-chromosome comes from the bitch. In most cases female dogs are carrier of one mutated x-chromosome without being diseased (conductor). According to Mendel's Law of Inheritance, 50% of the male puppies of a carrier bitch will have the mutated x-chromosome and express the disease and 50% of the female puppies will be healthy carriers (conductors). Female dogs will be diseased when they have two mutated x-chromosomes (one from the mother, one from the father). In that case both, father and mother must have the mutated x-chromosome (e.g. diseased male dog bred to conductor bitch).
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Description |
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DNA test
The mutation responsible for haemophilia A can now be identified using our DNA-test. The test can be performed on dogs of any age and even puppies can be tested. The DNA test does not only differentiate healthy and diseased dogs, but furthermore identifies healthy carrier (female) dogs. This is of crucial importance for dog breeders.
To achieve a maximum reliability of the test result, we perform the DNA-test of each submitted sample in two independent test runs.
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Trait of Inheritance |
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There are 3 possible genotypes:
1. Homozygous healthy:
Genotype female: N(X)/N(X),
Genotype male: N(X)/Y (homozygous healthy)
A dog like this is healthy and does not carry the mutated x-chromosome.
Offspring of this dog will not get the mutated x-chromosome.
2. Heterozygous carrier (only female):
Genotype female: N(X)/FVIII(X) (heterozygous carrier)
A bitch like this carries one copy of the mutated gene. It is unlikely that the bitch will suffer from haemophilia A, however there is a 50% chance that she will pass on the mutation to her offspring.
3. Homozygous affected:
Genotype female FVIII(X)/FVIII(X) (homozygous affected)
Genotype male FVIII(X)/Y (hemizygous affected)
Because of the x-chromosomal mode of inheritance, a homozygous affected female dog carries two mutated x-chromosomes and a hemizygous affected male dog carries one mutated x-chromosome. Female and male affected dogs have a high risk to express haemophilia A. The bitch will pass on the mutation to a 100% of her offspring and 50% of the offspring of the male dog will get the mutated x-chromosome.
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Inheritance : X-LINKED
RECESSIVE
trait
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Sire |
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Dam |
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Offspring |
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Males |
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Females |
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clear
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clear
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100% clear
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100% clear
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clear
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carrier
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50% clear + 50%
affected
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50% clear + 50%
carriers
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clear
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affected
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100% affected
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100% carriers
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affected
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clear
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100% clear
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100% carriers
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affected
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carrier
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50% affected + 50% clear
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50% affected + 50%
carriers
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affected
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affected
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100% affected
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100% affected
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Male:
Clear
Genotype: N [ normal ]
The dog is noncarrier of the mutant gene.
The dog will never develop Haemophilia A (factor VIII deficiency / F8) and therefore it can be used in breeding and should only be bred to clear females.
Affected
Genotype: FVIII [ mutant ]
The dog carries the mutant gene and will pass it its entire female offspring.
The dog will develop Haemophilia A (factor VIII deficiency / F8) and will pass the mutant gene to its entire female offspring
Female:
Clear
Genotype: N / N [ Homozygous normal ]
The dog is noncarrier of the mutant gene.
The dog will never develop Haemophilia A (factor VIII deficiency / F8) and therefore it can be used in breeding and should only be bred to clear females.
Carrier
Genotype: N / FVIII [ Heterozygous ]
The dog carries one copy of the mutant gene and one
copy of the normal gene.
The dog will never develop Haemophilia A (factor VIII deficiency / F8) but since it carries the mutant gene, it can pass it on to its offspring.
Affected
Genotype: FVIII / FVIII [ 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 will develop Haemophilia A (factor VIII deficiency / F8) and will pass the mutant gene to its entire female offspring
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Price
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£ 48.00 (including VAT)
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