Canine Phosphofructokinase (PFK) Deficiency Canine Phosphofructokinase (PFK) Deficiency is an autosomal recessive genetic disease that inhibits a spaniel’s ability to convert sugar into energy. Spaniels affected by PFK will often exhibit signs of exercise intolerance. Additionally, PFK destroys the red blood cells that deliver oxygen and remove waste throughout the spaniel’s body. This destruction of red blood cells causes the dog to become mildly or moderately anemic and also shows signs of exercise intolerance. A simple blood test by your veterinarian is all that is required to test for PFK. Results from a PFK test will yield one of three possible outcomes: normal/clear, affected, or a carrier. A spaniel that tests "Normal/Clear" indicates that s/he does not carry the PFK deficiency and cannot pass it on to his or her offspring when bred to another PFK Normal/Clear spaniel. A spaniel that tests "Affected" will show outward signs of exercise intolerance and will not be able to tolerate the physical demands placed on him/her in the field. A "Carrier" of the disease shows no outward signs of the PFK deficiency, but can pass it on to their offspring when bred. The only sure-fire way to prevent the proliferation of PFK through breeding is to test both the sire and dam prior to breeding and ensure they are both PFK Normal/Clear. The results of the PFK test can be registered with the Orthopedic Foundation for Animals (OFA). Further information about the OFA’s Registry of PFK Deficiency in Spaniels can be obtained by contacting: The Orthopedic Foundation for Animals, 2300 E. Nifong Boulevard, Columbia, MO 65201-3856, Phone (573) 442-0418. Or visiting their website at http://www.offa.org/