PK Def (Pyruvate Kinase Deficiency)


Pyruvate kinase (PK) deficiency is an inherited disease. Pyruvate kinase is an enzyme found within red blood cells which enables them to produce energy to survive. If this enzyme is lacking, the lifespan of the red blood cells is significantly reduced, resulting in a reduction in the number of red blood cells in the circulation (anaemia).

What signs does it cause?

The main consequence of the disease is the development of anaemia. However, since the body can quickly manufacture new red blood cells, the anaemia is usually only intermittently detectable. Most of the time the anaemia is either only mild, or occurs gradually, enabling the cat to adapt to the anaemia and not show any obvious signs. Anaemia often results in only vague signs such as lethargy and lack of appetite. However, a rapid severe life-threatening anaemia can also develop. Although PK deficiency is hereditary, the anaemia is usually mild and clinical signs may not be obvious, and thus may not be noticed until the cat is quite old.

How is PK deficiency inherited?

The disease is inherited as an autosomal recessive trait. This means that a cat can be carrying the defective gene (heterozygous) without having any symptoms of the disease at all. Affected cats (homozygous) arise when two carrier cats are mated with each other. Since carrier cats remain healthy, and the anaemia of affected cats may not be detected until they are a few years of age, the potential exists for carrier cats and affected cats to have had significant numbers of offspring before the disease is identified. However, the positive side of this is that it also means if carrier cats are identified they can still be used for breeding as long as we ensure that they are NOT mated with another carrier. Mating a carrier with a non-carrier will not produce any offspring that will suffer from PK deficiency, and 50 per cent of the offspring will be free of the defective gene. As long as the offspring are also tested, even carriers can be bred from again as long as it is ensured that they are only mated with a non-carrier cat. In this way, controlled breeding programmes can be implemented so that important lines can be retained within the gene pool.

What tests are available and can carrier cats be detected?

Fortunately a reliable test does exist for PK deficiency. It comprises a DNA test that is performed on either a blood sample or cheek swab. Affected cats as well as carrier cats can be identified with the test.

Why worry about PK deficiency?

PK deficiency is inherited and although predominately a problem in the US it is being reported increasingly in cats throughout Australia, New Zealand and Europe, including the UK.

* As described above, the clinical signs that develop can be serious and life threatening.

* Because initial clinical signs can be mild or go unnoticed, affected cats may not be identified until after they have had large numbers of offspring.

* Carrier cats do not show any clinical signs at all. The disease occurs when two carrier cats are mated with each other. This is important because a large number of carrier cats can arise in a population before PK deficiency is even noticed.

* With any genetic disease, by the time the disease becomes an obvious problem within a population it is much more difficult to control and involves a lot more expense and heartbreak.


ALL OUR BREEDING CATS ARE PK Def TESTED (DNA). MOST OF THEM ARE TESTED NORMAL HOWEVER WE HAVE ONE HETEROZYGOUS AND ONE HOMOZYGOUS GIRL. THEY ARE MATED ONLY WITH NORMAL TESTED BOYS AND DO NOT PRODUCE AFFECTED KITTENS.

More info here.


Interpretation of test results:

A Normal autosomal recessive PK Def genetic test result means that the cat does not have the genetic mutation causing pyruvate kinase deficiency.

A Heterozygous autosomal recessive PK Def genetic test result means that the cat has one copy of the mutation. The cat will not have pyruvate kinase deficiency, but may pass the mutation to their offspring.

A Homozygous autosomal recessive PK Def genetic test result means that the cat has two copies of the mutation. The cat will have pyruvate kinase deficiency.