Phosphofructokinase Deficiency (PFK)

What is PFK Deficiency?

PFK Deficiency is an enzyme storage disease which causes abnormalities in red blood cells and muscle cells. M-PFK is an enzyme required for the conversion of glucose into useable energy. Without the PFK enzyme, cells cannot produce enough energy for their needs.

The condition is inherited in English Springer Spaniels through a single autosomal recessive mutation - for a dog to be affected with clinical signs, it must have inherited TWO copies of the mutated PFK gene (one from each parent). A dog with one copy will itself be healthy but can pass on the mutation to its offspring. For a further explanation of genetic inheritance, click on the icon at the bottom of this page.

All the evidence suggests that the PFK mutation is uncommon in the UK ESS population. Nevertheless, breeders cannot afford to be complacent.

What are the symptoms?

A hallmark sign of this disease is intermittent dark urine (the colour ranging from orange to dark coffee-brown), and, in severe cases, pale gums (anaemia) or jaundice (yellow colouration of skin and gums), with fever and poor appetite. Clinical signs (most notably the dark urine) commonly develop following strenuous exercise, prolonged barking, or extensive panting, all of which are conditions that accelerate the destruction of red blood cells in affected dogs.

PFK Deficiency can present as anything from mild to life-threatening episodic illness. Clinical signs may be particularly noticeable in field trial/active working dogs, where weakness, exercise intolerance, muscle cramps, poor performance or even outright refusal to move, may be observed.

What is the treatment?

It is essential to get a proper diagnosis, as PFK Deficiency can sometimes be confused with Autoimmune Haemolytic Anaemia and other acquired diseases.

Clinical manifestations usually resolve within hours to days. While there is no actual treatment for Phosphofructokinase Deficiency, it can be successfully managed to the point that affected dogs may have a relatively normal lifespan. The most important ‘treatment’ is managing the dog’s activity and stress levels, to prevent more severe anaemia. Situations that can precipitate such crises (including strenuous exercise or stress) should be avoided. In cases where anaemia becomes critical, veterinary care is required to manage the condition until it normalises.

Can PFK be prevented?

A simple DNA test is available for PFK Deficiency.

A DNA test makes PFK completely preventable. A tiny change (point mutation) in the M-type phosphofructokinase gene was identified by research groups at the University of Pennsylvania, which has resulted in the availability of a genetic screening (DNA) test for PFK Deficiency. This test accurately determines the genetic status of a dog as either:

  • CLEAR: The dog has two normal copies of the PFK gene. It will not have PFK, nor can it pass on a copy of the mutant gene to any offspring;

  • CARRIER: The dog has one normal copy and one mutant copy of the PFK gene. It will not clinically suffer from PFK, but it can pass on the mutant gene to its offspring;

  • AFFECTED: The dog has two mutant copies of the PFK gene. It will be clinically affected with PFK and will always pass on the mutant gene to any offspring.

Clinically affected puppies cannot be produced if at least one parent in any mating is genetically Clear.

DNA Test Procedure

  • The PFK test uses a buccal (cheek) swab for DNA analysis, a completely non-invasive method of sample collection.

  • The sample can be collected by owners or by a qualified Vet if owners prefer the sample ID to be independently verified.

Kennel Club Recording of PFK DNA Test Results

  • An official ESS/Kennel Club Breed Scheme is in place, whereby PFK DNA test results notified to the KC will be added to the details of KC registered dogs and will appear on any new registration certificate issued for the dog and on the registration certificates of any future offspring of the dog. The results will be published in the Breed Records Supplement and appear on the Health Test Results Finder on the Kennel Club website.

  • To find PFK test results for individual dogs click on Health Test Results Finder.

  • To find lists of PFK tested dogs and their genetic status, click HERE. Scroll down to 'Health' and click on 'More about health', then 'Important health schemes and tests'. **These lists do not include ‘hereditarily clear’ dogs (i.e. dogs that have themselves not been tested as they are the product of two CLEAR parents).

If any ESS owner and/or breeder needs help or further information relating to PFK, we would be happy to hear from them. We would also be grateful if owners would contact us to report a diagnosis of PFK, or report it online HERE. All information provided will be treated in the strictest confidence.

For further information or advice about PFK, please contact the

ESS Breed Clubs Health Co-ordinators