Pyruvate Kinase Deficiency in Cats
Pyruvate kinase deficiency in cats is an inherited disorder caused by a mutation in the PK-LR gene. This disease has an autosomal recessive pattern, which means that an affected individual requires two copies of the PK-LR gene. However, carriers of only one copy of the gene are not affected clinically. Different breeds of cats and dogs exhibit different mutations in the PK-LR gene.
Symptoms
Symptoms of PK deficiency in cats can be very varied. Those with severe cases may die of anemia. Other cats may have a milder form of the disease and show no symptoms at all. Cats with milder cases may show signs of anemia, such as a lack of red blood cells. A healthy cat will have pink gums and well-oxygenated blood.
Clinical signs vary from cat to cat but are generally present before the age of two. These symptoms include chronic severe hemolytic anemia, hemosiderosis, abnormal hardening of bones, and lethargy. In dogs with PK deficiency, life expectancy is drastically reduced and most are humanely euthanized at two years old. Although cats may not show any clinical signs, they may exhibit lethargy, weakness, and anemia. In rare cases, the disease may lead to sudden severe anemia.
Despite the severity of these symptoms, a blood transfusion is a good option for newborn kittens, as it supports growth and minimizes the effects of the disorder. PK deficiency is most commonly associated with the spleen, and a cat affected by this disorder may need to undergo a splenectomy. In severe cases, your veterinarian may prescribe a vitamin D or folic acid supplement to replace the missing red blood cells.
Causes
PK deficiency causes a mutation in the PKLR gene. The mutation results in the deficiency of a single cat enzyme. It is a rare hereditary disorder that affects cats of both sexes. PK deficiency is a genetic condition inherited through an autosomal recessive trait. The cat must have both defective genes to develop the disorder. Cats can also be heterozygous, wherein one gene is defective and the other is normal. If two cats have heterozygosity, they will have an equal distribution of both normal and abnormal genes. A heterozygous cat develops no symptoms of PK deficiency unless they bred with another N/P animal.
Anemia is a common symptom in cats with PK deficiency, particularly in mild cases. This is because the cat’s bone marrow cannot keep up with the continuous loss of red blood cells. A healthy cat will have pink gums and an adequate level of oxygen in its blood.
Diagnosis
Cats with PK deficiency suffer from anemia, a condition that reduces red blood cells and contributes to premature aging. Its signs vary, depending on breed and age. While cats may not show symptoms at first, they may develop lethargy, weakness, and even anemia. Ultimately, PK deficiency is fatal in up to six percent of cats.
Molecular analysis of PKLR gene sequences has identified three correlated SNPs. In five groups, one of these SNPs was present in a significant proportion of the affected cats.
Treatment _ Pyruvate Kinase Deficiency in Cats
In mild to moderate PKdef, a cat may experience anemia. This is because its bone marrow is no longer able to keep up with the constant loss of red blood cells, which transport oxygen. The cat may become lethargic, feel tired, play less, or breathe quickly to get oxygen. Blood tests may show increased platelets, white blood cells, or a variation in RBC color. A biochemistry profile may also show an excess of iron and mild increases in bilirubin. A urinalysis may also reveal an abnormally high level of bilirubin. Although the disease is treatable with a bone marrow transplant, this treatment is highly expensive and life-threatening.
In the corresponding human gene, there are 158 novel mutations that result in PK deficiency. The domestic cat PKLR gene, type-R CDS transcript, shares a similar genetic sequence with humans, with 88% homology at DNA and protein sequence levels.
