Phosphofructokinase Deficiency in Dogs: Symptoms, Breeds & Testing

Phosphofructokinase deficiency (PFK) in dogs is a hereditary metabolic disorder caused by a lack or malfunction of the enzyme phosphofructokinase, vital for energy production, particularly in red blood cells and skeletal muscles. This enzyme deficiency impairs the breakdown of glucose necessary to meet energy demands, especially during exercise or heat exposure, resulting in symptoms such as muscle weakness, anaemia and exercise intolerance.

Understanding Phosphofructokinase Deficiency in Dogs

PFK deficiency leads to premature destruction of red blood cells (haemolysis) and muscle cell damage, often triggered by strenuous physical exertion, overheating, prolonged barking or excitement. Affected dogs may experience tiredness, muscle cramps, poor exercise tolerance, jaundice and dark, strong-smelling urine following exertion. Symptoms can fluctuate but require attentive care to prevent serious complications.

Which Breeds Are Affected?

This condition is predominantly found in breeds from the spaniel family including the American Cocker Spaniel, English Springer Spaniel, German Spaniel, and also in whippets. Crossbreeds featuring these ancestries can also inherit the condition, so responsible breeders test breeding stock thoroughly to avoid passing on this disorder.

How PFK Deficiency is Inherited

PFK deficiency follows an autosomal recessive inheritance pattern, meaning that a dog must inherit two copies of the faulty gene—one from each parent—to be affected. Different combinations of parental genetic status result in varying outcomes for the litter:

• If neither parent is affected or a carrier, the litter will be clear.
• If both parents are affected, all puppies will be affected.
• If one parent is affected and the other clear, all offspring will be carriers only.
• If one parent is affected and the other a carrier, puppies have a 50% chance of being affected or carriers.
• If both parents are carriers but unaffected themselves, each puppy has a 25% chance of being affected, 50% carriers, and 25% clear.

Managing the Condition

Currently, no cure exists for PFK deficiency. Treatment focuses on managing symptoms and improving quality of life. This includes avoiding intense exercise, overheating and stress, offering a balanced diet with proper energy sources, and regular veterinary check-ups to monitor for anaemia or kidney issues. Bone marrow transplantation can potentially resolve the condition but is costly and rarely undertaken.

Getting Your Dog Tested

If your dog is of an at-risk breed and you plan to breed, it is vital to have them tested for PFK deficiency. Your vet can collect a DNA sample for genetic testing at approved laboratories associated with The Kennel Club. This testing supports responsible breeding and helps reduce the incidence of this condition.

Making Responsible Breeding Decisions

Responsible dog breeding means prioritising health, welfare and genetic diversity over appearance or popularity. Testing for hereditary conditions like PFK deficiency ensures breeders avoid producing affected puppies, promoting healthier breeds overall and supporting the well-being of the wider dog community.

Conclusion

Phosphofructokinase deficiency is a serious hereditary metabolic disorder primarily affecting certain spaniel breeds and whippets. Although incurable, dogs with PFK deficiency can live good quality lives if managed carefully to avoid triggering symptoms. Genetic testing before breeding plays a crucial role in preventing this condition and encouraging responsible dog ownership.

By understanding the condition, recognising symptoms early, and supporting informed breeding, we can reduce the impact of PFK deficiency in the dog population, improving welfare for generations to come.