Pyruvate Kinase Deficiency (PKDef) in Labrador Retrievers

Quick Summary

Pyruvate kinase deficiency in Labrador Retrievers is a chronic, severe hemolytic anemia caused by defective production of the enzyme pyruvate kinase. Signs in affected dogs may include lethargy, low exercise tolerance, and fatigue.

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Phenotype: Observable signs in affected dogs may include lethargy, low exercise tolerance, and fatigue. Clinically, affected dogs present with severe anemia, increased bone density, enlarged spleen and liver as well as fibrous connective tissue replacement of bone marrow cells. Signs usually appear between 4 months and 2 years of age, and prognosis is generally poor for affected individuals, with complete liver failure typically occurring by 5 years of age.

Mode of Inheritance: Autosomal recessive

Alleles: N = Normal, K = Pyruvate kinase deficiency

Breeds appropriate for testing: Labrador Retriever, Labradoodle

Explanation of Results:

  • Dogs with N/N genotype will not have pyruvate kinase deficiency and cannot transmit this pyruvate kinase deficiency variant to their offspring.
  • Dogs with N/K genotype are not expected to show signs of pyruvate kinase deficiency but have half the normal level of pyruvate kinase activity, and are carriers of this variant. They may transmit this pyruvate kinase deficiency variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% pyruvate kinase deficiency-affected puppies.
  • Dogs with K/K genotype will have pyruvate kinase deficiency, prognosis is poor. 

Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)

Turnaround Time
At least 15 business days; may be delayed beyond 15 business days if sample requires additional testing, or a new sample is requested.
Price

$55 single test per animal ($5 discount on 3 or more dogs)

$25 as additional health test on same animal

Sample Collection

Dog DNA tests are carried out using cells brushed from your dog's cheeks and gums. The preferred cytology brushes are sent to you by mail, or you may provide your own brushes. For accepted alternative brushes, click here

We recommend waiting until puppies are at least three weeks old before testing.

 

Dog having its cheeks and gums brushed for DNA samples
Cheek and gum brushing technique for canine DNA sample collection

Step-By-Step:

  1. Make sure the dog has not had anything to eat or drink for at least 1 hour prior to collecting sample.
  2. When swabbing puppies, isolate each puppy from the mother, littermates and any shared toys for 1 hour prior to swabbing. Puppies should not have nursed or eaten for 1 hour prior to collecting sample.
  3. If collecting samples from more than one dog, make sure to sample one dog at a time and wash your hands before swabbing another dog.
  4. Label brush sleeve with name or ID of dog to be sampled.
  5. Open brush sleeve by arrow and remove one brush by its handle.
  6. Place bristle head between the dog’s gums and cheek and press lightly on the outside of the cheek while rubbing or rotating the brush back and forth for 15 seconds.
  7. Wave the brush in the air for 20 seconds to air dry.
  8. Insert brush back into sleeve.
  9. Repeat steps 5 - 8 for each unused brush in sleeve on a fresh area of cheek and gums. Make sure to use and return all brushes sent by the VGL. In most cases, it will be 3 brushes per dog. If using interdental gum brushes, please note that the VGL requires 4 brushes per dog and only moderate or wide interdental gum brushes are accepted.
  10. Do not seal brushes in sleeve.
  11. Place all samples in an envelope and return to the address provided.

ATTENTION:

  • Do not collect saliva/drool – the key to obtaining a good sample is getting cheek cells on the swab
  • Do not rub swab on the dog’s tongue or teeth – this will result in poor quality sample
  • Do not collect a sample from a puppy that has recently nursed – the mother’s genetic material can rub off on the puppy’s mouth and contaminate the sample
Additional Details

Pyruvate kinase deficiency (PKDef) is a chronic, severe hemolytic anemia caused by defective production of the enzyme pyruvate kinase. Low levels of this enzyme result in premature death of red blood cells and insufficient supply of oxygen to the body’s cells. Observable signs in affected dogs may include lethargy, low exercise tolerance, and fatigue. Clinically, affected dogs present with severe anemia, increased bone density, enlarged spleen and liver as well as fibrous connective tissue replacement of bone marrow cells. Signs usually appear between 4 months and 2 years of age, and prognosis is generally poor for affected individuals, with complete liver failure typically occurring by 5 years of age.

PKDef in Labrador Retrievers is caused by a single nucleotide mutation (c.799C>T) in exon 7 of the Pyruvate Kinase L/R (PKLR) gene. The mode of inheritance for this disease is autosomal recessive, which means that males and females are equally affected and that two copies of the mutation are needed to cause PKDef. Screening of a random set of Labradors Retrievers at the VGL determined that the PKLR disease allele is rare in this breed, with frequency less than 1%.

Testing for PKDef assists clinicians with diagnosis of PKDef and helps breeders identify carriers among the breeding population. Carrier dogs, those with one defective and one normal copy, show no signs of disease but have half the normal level of pyruvate kinase activity. Breeding between two carriers is not recommended because 25% of the offspring are expected to be affected and 50% are expected to be carriers of the disease.