Jump to topic
PK deficiency was first documented in an Abyssinian cat in the U.S.A. Later, other reports and experiments demonstrated that several Somalis cats from Australia also had PK deficiency.
Today, PK deficiency has been diagnosed in other cat breeds.
Want to know the best DNA testing kit for your cat? Read our 2021 Guide.
What is PK deficiency?
PK deficiency (erythrocyte pyruvate kinase deficiency) is an inherited genetic condition common in Abyssinian and Somali cat breeds. The deficiency also occurs in randomly bred domestic shorthair cats.
The PK deficiency results from the genetic mutation of the PKLR (Pyruvate kinase, liver, and red blood cells) gene, which regulates the actions of the pyruvate kinase enzyme in the glycolytic pathway. When this enzyme undergoes mutation, it decreases the longevity of the red blood cells.
Enzymes are important proteins in the animal body. Genes play a crucial role by giving out relevant information for the production of certain proteins and enzymes. When there's a mutation of a particular gene, the protein produced may not work properly or may even become absent.
The pyruvate kinase (PK) enzyme supplies the red blood cell with the energy needed for its function and survival. This process of providing energy occurs through glycolysis, in which sugar is converted to energy for use. When the PK enzyme is short in your cat's red blood cells, your cat becomes PK deficient and may suffer from hemolytic anemia (red blood cell shortage).
What are the signs of PK deficiency in Cats?
PK deficiency is not much noticeable in cats due to their adaptive nature. The bone marrow produces new red blood cells as soon as it detects a shortage in your cat's blood. However, this process can reach a point of exhaustion, and the signs of PK deficiency become obvious.
The early sign of the disease comes with the inability to move around for long due to PK deficiency-induced anemia. Other signs may include:
- Lack of appetite
- Poor coat quality
- Weight loss
- Pale mouth skin
Most anemia caused by PK deficiency is mild. However, some cases can be severe and life-threatening. In a study conducted on 18 Abyssinian and Somali cats, the signs of anemia manifested early (about six months) and as late as five years. Some cats live through the severity of the anemia, while some lived with it for a longer time.
Sometimes, the clinical signs of PK deficiency remain unclear until your cat has lived through it and is already old. Most cats at this stage are usually euthanized if the anemia is severe or properly managed if it's mild.
What causes pyruvate kinase deficiency?
PK deficiency is an inherited genetic condition. Normally, a single pair of genes (NP gene) controls the expression of PK deficiency. These genes can express themselves in many forms.
Cats with the NN gene are dominant carriers; they won't suffer from PK deficiency and will not transmit PK deficiency to their kittens.
Cats with the NP gene are carriers. They will not suffer from PK deficiency but are likely to transmit the gene to their kittens. A random mating between two carrier cats is expected to transfer 50% of the gene to their kittens. However, only 25% of the kittens will be PK deficient.
Cats with the PP gene are recessive and would 100% suffer from PK deficiency. They are also more likely to transmit the gene to all their kittens. In this case, genetics cannot predict the severity of the deficiency, although it can help you detect it.
Genetic (PK) tests help cat owners and breeders identify affected and carrier cats and take precautions when mating.
What is a PK test? Does my cat need it?
The PK test is a DNA (genetic) test that you can perform on your cat to determine the PK levels in their blood. This test can be conducted on your cat's cheek swab or blood samples.
This test works by a proper analysis of the cat's PKLR gene and how it's expressed in the production of the pyruvate kinase enzyme. The PK test screens the gene's activity and confirms if your cat inherited the affected genotype or the carrier genotype.
It's a Mutation-based Test with great advantages. The PK test can identify the genetic defect leading to the disease. Using DNA testing, the mutated genes can be detected and, if possible, corrected. The PK test is highly accurate and can be performed on cats of all ages.
The PK test offers the possibility to differentiate between affected and carrier cats and identify clinically healthy carriers. This information can help in controlling the disease in the cat population. It can help reveal more information missed by common laboratory diagnoses.
The test is reliable because it can help detect the condition directly from the genes. Early detection can help prevent future mating between two affected cats. It can also help the cat owner explore available treatment options.
For example, if a cat turns out to be a carrier, a breeder can breed the cat with a non-affected cat. This means that the non-carrier kittens can be saved for the upcoming round of breeding.
Not all cats need a PK test, but it's necessary to test your cat and discover for yourself to avoid mistakes.
For now, PK testing is recommended for the following cat breeds:
- Egyptian Maus
- La Perms
- Maine Coon cats
- Norwegian Forest cats
- Somalis cats
Other breeds that resulted from Abyssinian crosses such as the Ocicat should also be tested. The tests should also be conducted on domestic shorthair cats that are randomly bred with either the Abyssinian or the Somalis cat breeds.
How can I test my cat for PK deficiency?
You can test your cat using the DNA test methods. Many DNA companies offer this service, and you can get your results in about two weeks.
How often should I test my cat for PK deficiency?
Most signs of PK deficiency are vague. They also vary with the breed and age of the cat. Some of these signs become clear as the cat gets older, and some are noticed when they are younger. If your cat is one of the breeds susceptible to PK deficiency, you might need to test it twice - at birth and the adult stage.
However, the best thing to do is to take your cat to the vet at least once annually. Your vet will run a proper diagnosis on your cat to determine if it needs a PK test in the first place. A regular visit to the vet will save you a lot of doubt, guessing, and worry.
If you're bothered about your cat being PK deficient, you can contact your vet as soon the kittens are born; or if you notice any abnormal behavior or signs from your cat. The vet will likely give you more reliable information than your guesses would.
Treatment options for PK deficiency
There are no permanent cures for PK deficiency. However, proper management of the condition would require a collaborative effort between the cat owner and the veterinarian doctor. The treatment options available for PK deficiency involve prolonging the lifespan of your cat and managing the symptoms.
Some treatment options available include Blood Transfusion Therapy. This method involves an active transfusion of blood to replenish the depleted red blood cells in the blood. The blood transfusion option is recommended at the early stage of the disease and for newborn kittens. This helps to support growth and development, and also reduce symptoms such as lack of appetite, fatigue, and weight loss.
PK deficiency is also most likely to affect the spleen and cause splenomegaly (enlargement of the spleen). In any case, where this occurs, splenectomy (surgical removal of the spleen) is usually recommended.
Other supportive care is also recommended. You can supplement your cat's diet with vitamin D and folic acid. Both supplements help with the replenishment of the red blood cells.
PK deficiency is a rare genetic condition that occurs in cats of selected breeds. It depletes the red blood cells in the blood and leads to anemia. It is crucial to check your cats described in the article to know if it requires a PK test.
A PK test will help you to know whether your cat is a carrier or if it's affected. The information provided from the PK test helps you to be cautious when it's time to breed your cat. You would not want to breed your cat with a PK deficient cat. This makes the PK test an important test to consider.
The best practice, however, is to visit your veterinary doctor regularly for the best advice. Your vet is an expert who knows more about the clinical side of your cat than anyone. A regular visit not only improves your cat's well-being but also saves you some cash when you detect the disease early.
The Definitive Guide to Cat DNA testing: What you need to know.