Disease overview

Glycogen storage disease, Type VII (GSD-VII) is also known as hereditary muscle-type phosphofructokinase (PFK) deficiency. It causes intermittent hemolytic anemia and exertional myopathy due to a mutation in the PFKM gene. As a result of the mutation, affected dogs have insufficient activity of the PFK enzyme, which is responsible for breaking down glycogen for energy.

Gene name

PFKM

Inheritance

Autosomal recessive

Signs and symptoms

In addition to hemolysis (destruction of red blood cells), dogs with this condition can present with skeletal muscle cell damage. Pale gums, lethargy, and exercise avoidance can all be signs of this disorder. Red/brown urine, jaundice, and muscle cramping can accompany periods of exercise, excitement, or stress in affected dogs. Dogs with GSD-VII have normal life expectancy; however, recurring hemolytic episodes after different types of activity are common. Muscle wasting can sometimes progress to the inability to walk.

How is it diagnosed

A veterinarian will review health history, conduct a thorough exam, and note any clinical signs. Laboratory testing and a liver biopsy may be indicated to help determine a diagnosis. Genetic testing is necessary to determine if there is an underlying genetic cause, which can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

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Citations

Inal Gultekin G, Raj K, Lehman S, Hillström A, Giger U. Missense mutation in PFKM associated with muscle-type phosphofructokinase deficiency in the Wachtelhund dog. Mol Cell Probes. 2012 Dec;26(6):243-7. doi: 10.1016/j.mcp.2012.02.004. Epub 2012 Mar 16. PMID: 22446493; PMCID: PMC3485442.

Gerber K, Harvey JW, D'Agorne S, Wood J, Giger U. Hemolysis, myopathy, and cardiac disease associated with hereditary phosphofructokinase deficiency in two Whippets. Vet Clin Pathol. 2009 Mar;38(1):46-51. doi: 10.1111/j.1939-165X.2008.00089.x. Epub 2008 Oct 28. PMID: 19228357; PMCID: PMC2692053.

Smith BF, Stedman H, Rajpurohit Y, Henthorn PS, Wolfe JH, Patterson DF, Giger U. Molecular basis of canine muscle type phosphofructokinase deficiency. J Biol Chem. 1996 Aug 16;271(33):20070-4. doi: 10.1074/jbc.271.33.20070. PMID: 8702726.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.