Phosphofructokinase deficiency (PFK) is a genetic disease of dogs characterized by intermittent hemolytic anemia and exertional myopathy.
PFK results in a glycolytic block leading to reduced ATP and 2,3-diphosphoglycerate (DPG) concentrations. This leads to elevated hemoglobin-oxygen affinity and tissue hypoxia, which acts as a persistent stimulus for increased erythropoiesis even when the HCT is normal.
In addition to persistent compensated hemolytic anemia, PFK-deficient dogs (but not humans) may have episodes of intravascular hemolysis following periods of hyperventilation-induced alkalemia due to low DPG concentrations.
In PFK dogs, the hemolytic crises is typically initiated by strenuous exercise, barking, heat or excessive panting.
Clinically affected dogs present with acute exercise intolerance, exertional myopathy muscle stiffness, pale and sometimes icteric mucus membranes and a mild systolic heart murmur. Urinalysis often shows a prominent hemoglobinuria.
Diagnosis is established by finding a marked reduction in erythrocyte PFK activity (often less than 1 IU/g Hb; normal = 5 - 20 IU/g Hb).
DNA testing is available for the English Springer Spaniel and American Cocker Spaniel breeds.
Reduction of stress and exercise restriction often allows affected dogs to lead a normal life.
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- Gerber K et al (2009) Hemolysis, myopathy, and cardiac disease associated with hereditary phosphofructokinase deficiency in two Whippets. Vet Clin Pathol 38(1):46-51
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- Gerber K et al (2009) Hemolysis, myopathy, and cardiac disease associated with hereditary phosphofructokinase deficiency in two Whippets. Vet Clin Pathol 38(1):46–51