Pyruvate Kinase Deficiency

Pyruvate Kinase deficiency is a hereditary hemolytic anemia that that closely resembles human PK deficiency and results from a deficiency of the essential red blood cell enzyme pyruvate kinase (PK). This enzyme helps convert glucose to energy when oxygen is low. If the amount of PK is deficient, the red blood cells break down more rapidly than usual. This destruction can result in hemolytic anemia, or too few oxygen-carrying red blood cells.

Breeds at Risk

The mode of inheritance in the Basenjis and Beagles is autosomal recessive which means that a dog must get the defective gene from both parents to develop the disorder. The age at detection of hemolytic anemia is always less than 6 months, and usually less than 3 years.

The PK deficiency leads to impaired glucose utilization and consequently premature red cell destruction. In late phases of the disease, the bone marrow becomes exhausted and may become scarred ( a condition called myelofibrosis). At this point, the anemia is terminal.

Signs of Pyruvate Kinase Deficiency

Affected dogs are less tolerant of exercise than normal litter mates. They usually die of myelofibrosis, osteosclerosis or liver failure by 3 to 5 years of age.

Diagnosis and Treatment of Pyruvate Kinase Deficiency

Diagnosis can be confirmed by measuring red cell PK levels. There is no cure for this condition.

Breeding plans can be managed through use of laboratory tests that can identify heterozygotes, although some overlap exists in the ranges for enzyme values between homozygote normal and heterozygote carriers.

References:
1. A Guide to Hematology in Dogs and Cats by Alan H. Rebar (2002) 2. Essentials of Veterinary Hematology By Nemi Chand Jain
3. Ultrastructural Pathology: An Introduction to Interpretation By Norman F. Cheville