Pyruvate Kinase Deficiency

What is Pyruvate Kinase Deficiency in dogs?

Red blood cells ChevromistPyruvate Kinase Deficiency (also known as PKD) is a metabolic disorder that is inherited in an autosomal recessive pattern. Essentially, affected dogs lack and enzyme called Pyruvate Kinase that is required by every cell in the body to breakdown glycogen for energy. This enzyme is one of the key enzymes in the pathway of turning food into energy inside the cells of the body. A lack of this enzyme results in reduced energy available to the cell to perform it’s function in the body as well as to survive for a normal length of time. Pyruvate Kinase Deficiency affects the red blood cells of the affected dog more than any other cell type and the symptoms of the condition represent the inability of the red blood cells to function normally. Unfortunately, there is no cure for this disease but DNA Disease Screening does allow us to prevent dogs from inheriting Pyruvate Kinase Deficiency.

Genetics of Pyruvate Kinase Deficiency in dogs

The condition of Pyruvate Kinase Deficiency is a result of a number of different mutations in the PKLR gene. Different breeds tend to carry different types of mutations of this gene, but all mutation types result in the same clinical disease called Pyruvate Kinase Deficiency. All forms of known mutations have an autosomal pattern of inheritance, meaning that a copy of a mutated gene must be inherited from each parent for a dog to be affected. A dog with 2 mutated genes in called Affected, 1 normal and 1 mutated is a Carrier and 2 normal copies of the PKLR gene is called Clear. Having 1 Clear parent will prevent all of the offspring in the litter to be unaffected, regardless of the status of the other parent.

What is the severity of Pyruvate Kinase Deficiency in dogs?

Pyruvate Kinase Deficiency is classified as a highly severe disease as the condition affects young dogs, has no cure and is ultimately fatal within a short time from the onset of symptoms.

What are the symptoms of Pyruvate Kinase Deficiency in dogs?

Dogs affected by Pyruvate Kinase Deficiency will often display signs such as Anemia, weakness, pale mucous membranes, intolerance to exercise, tachycardia (high heart rate), muscle wasting, weight loss and an inability to perform what would be considered normal exercises. These symptoms will usually appear from the age of 4-12 months but they can remain hidden until the affected dog is 2 years old and some evidence has been put forward to suggest that inactive dogs will have a delayed onset and progression of the disease. As by Pyruvate Kinase Deficiency progresses, the affected dogs will often succumb to the effects of the worsening anaemia, hepatic (liver) failure and haemolysis.

Diagnosis of by Pyruvate Kinase Deficiency in dogs

Pyruvate Kinase Deficiency stained blood cellsTraditional blood testing will detect some of the clinical symptoms of by Pyruvate Kinase Deficiency such as the haemolysis and an examination of the red blood cells themselves often reveals abnormally-shaped RBCs called poikilocytes. Urine analysis may also reveal high levels of bilirubin. The most reliable way to definitively diagnose PKD is with DNA Disease Screening. This is the same testing that allows breeders to make informed choices about breeding mates to prevent their puppies from being affected by Pyruvate Kinase Deficiency.

Treatment of dogs with Pyruvate Kinase Deficiency

Treatment for Pyruvate Kinase Deficiency is largely limited to treating the symptoms of the affected dog as they arise to make the affected dog’s life more comfortable as there is no cure for this disease. Bone marrow transplants have been tried, but the net result has only been to very slightly delay the inevitable. Prevention via DNA Disease Screening is the best option of preventing this condition in offspring and offers a way to remove the mutated genes from future generations.

References

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