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PK Deficiency (Pyruvate Kinase Deficiency)
Test number: 8015
Gene: PK
Price: £ 48.00 (including VAT)
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Breeds
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Basenji
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Beagle
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Cairn Terrier
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Labrador Retriever
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Pug
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West Highland White Terrier
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The Disease |
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Pyruvate kinase (PK) is an enzyme critical to the anaerobic glycolytic pathway of energy production in the erythrocyte. If erythrocytes are deficient in PK they are unable to sustain normal cell metabolism and hence are destroyed prematurely. This deficiency manifests as an hemolytic anemia of variable severity with a strong regenerative response. In dogs, the anemia is always severe (PCV 10-20%) whereas in cats the anemia shows a regenerative response. Also associated with the disease in dogs but not cats is a progressive myelofibrosis and osteosclerosis of unknown etiology and this feature, along with liver failure, is the major cause of death in affected dogs.
The life expectancy of affected dogs is shortened and most die before 4 years of age.
PK deficiency has been recognized in both dogs and cats. The dog breeds involved are the Basenji, Beagle, Dachshund, Eskimo, West Highland White Terriers and the Beagle. In cats, PK deficiency has been described in Abyssinian and Somali cats, as well as DSH cats. The feline disease differs from the canine disease in that affected cats can have a normal life span, only intermittently have anemia, and do not seem to develop either osteosclerosis or liver failure. In all breeds the disease is inherited as an autosomal recessive condition. Heterozygotes (carriers) do not have any clinical signs of disease and lead normal lives. They are able to propagate mutations throughout the population however and it is therefore important that carrier animals be detected prior to breeding.
PK deficiency can be detected, using molecular genetic testing techniques, in the Basenji, Beagle, Pug, Labrador Retriever, West Highland White and Cairn Terriers and the Beagle. These tests identify both affected and carrier animals. It is also possible to identify animals deficient in PK activity through enzyme analysis in those breeds where a molecular genetic test is not available.
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Clinical Signs |
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The clinical signs of disease reflect the anemic status of the animal and include exercise intolerance, weakness, heart murmur and splenomegaly. The anemia is macrocytic, hypochromic and highly regenerative in dogs. Radiographs reveal generalized abnormalities in bone density including intramedullary mineralisation of the long bones suggestive of progressive osteosclerosis in dogs.
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Trait of Inheritance |
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PK Deficiency is inherited in an autosomal recessive trait.
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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 PK Deficiency (Pyruvate Kinase Deficiency). The dog will never pass the mutation to its offspring, and therefore it can be bred to any other dog.
Carrier
Genotype: N / PK [ 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 PK Deficiency (Pyruvate Kinase Deficiency) 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: PK / PK [ 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 PK Deficiency (Pyruvate Kinase Deficiency) 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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