Pyruvate Kinase Deficiency in Cats

Pyruvate kinase deficiency in cats is an inherited hemolytic anemia that is passed down from parents to offspring. An affected feline has an absence of the regulatory enzyme, pyruvate kinase, which is responsible for the metabolism of energy used to create more red blood cells. Without this specialized enzyme, the body cannot make enough erythrocytes to meet the demands of the body. A feline with this red blood cell abnormality will be mild to severely anemic. The disorder is commonly seen in Abyssinian and Somali breeds.

The most prominent sign of a pyruvate kinase deficiency in cats is anaemia. The lack of circulating red blood cells usually starts out as a mild condition and worsens over time, however, some felines may stay with a mild case of anaemia, never worsening. The diagnosis of anemia may change, as felines with pyruvate kinase deficiency often come in and out of an anaemic state. A deficiency of pyruvate kinase can have different effects on one cat than another, making the symptoms of this condition variable. Therefore, symptoms of Pyruvate Kinase Deficiency in cats may or may not include: 

• Pale mucous membranes 
• Presence of a swollen abdomen 
• An enlarged spleen 
• Weight loss
• Loss interest in food
• Weakness
• Jaundice 
• Tiredness 
• Rapid breath 
• Lethargy 
• Seizures 

Pyruvate kinase deficiency is a condition a cat is born with, but symptoms do not usually arise until the cat reaches three years of age. The disorder is a genetic mutation linked to specific cat breeds including; Somali, Singapura, Siberian, Savannah, Norwegian Forest, Maine Coon, LaPerm, Egyptian Mau, Domestic longhair, Domestic shorthair, Bengal and Abyssinian cats. Abyssinian and Somali cats are reported to be the highest carriers of this defective gene as it is estimated that 15 to 30 percent of the two breed populations are affected.

A proper diagnosis of pyruvate kinase deficiency in cats begins with a review of a feline’s medical history and physical examination. The veterinarian will want to discuss the recent symptoms you have noticed in your cat and ask you to provide any possible information you have regarding the feline’s genetic bloodline. Blood work, including a complete blood cell count and a biochemistry profile will likely be completed, revealing a mild to severe case of anemia. If the biochemistry profile, which measures the functionality of the bodily organs, comes back normal, your veterinarian may want to rule out the possibility of infection. The FIP, FIV and FeLV virus, or the bacterial infection known as Mycoplasma haemofelis, can also link a cat to anemia. Therefore, these infections, as well as the possibility of toxins and immune deficiencies, will need to be ruled out before testing for a pyruvate kinase deficiency.

Complete Blood Cell Count (CBC)

A complete blood count will reveal a low number of red blood cells or erythrocytes in a single field of view, diagnosing the feline with anemia. 

PK Def Genetic Test

A cat’s DNA can be tested for pyruvate kinase deficiency with a simple blood sample or cheek swab of collected cells. 

Pyruvate kinase deficiency has no curative treatment option. Treatment plans for felines with pyruvate kinase deficiency are directed towards management of symptoms and prolonging the animal’s lifespan. Felines with severe anemia associated with this disease might receive blood transfusion therapy to replenish the body’s erythrocyte supply. As red blood cells carry oxygen to the various organs in the body, a feline may be hospitalized to receive oxygen therapy. The spleen may enlarge so much in a cat with pyruvate kinase deficiency that the veterinarian will recommend a splenectomy, or removal or the spleen.

The prognosis for a feline with pyruvate kinase deficiency depends on the severity of the condition. A cat with mild anemia or anemia that comes and goes has a very high chance of living a long, relatively normal life. However, cats with severe cases of pyruvate kinase deficiency related anemia have a high risk of hospitalization and reduced lifespan. Veterinarians recommend that all offspring produced by the diagnosed male or female should be genetically tested for the genetic mutation. Those cats with a positive result on their PK Def DNA test should be spayed or neutered to prevent passing the mutation onto future generations.