Breeds Affected: English springer spaniel, American cocker spaniel, Whippet
Samples Accepted: Blood, Buccal Swabs
Disease Information: Glycogen Storage Disease VII (GSD VII) is also known as Phosphofructokinase Deficiency. Affected animals lack phosphofructokinase in their muscles, leading to exercise intolerance, muscle cramps, and occasional hemolytic crisis and related problems. Affected animals can have a normal lifespan.
Inheritance Information: GSD VII is autosomal recessive, meaning that animals with two copies of this allele will be affected. Animals with one copy of the gene will be clinically-normal carriers.
The possible genotypes are:
N/N The dog is normal, and cannot produce affected offspring.
N/gsd7 The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/gsd7 carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
gsd7/gsd7 The dog is affected, and should not be used for breeding.
– Carriers may be bred to normal animals (N/gsd7 x N/N) without any risk of producing affected offspring. The offspring should be tested before breeding to determine if they are carriers or normal.
– Breeding two carriers (N/gsd7 x N/gsd7) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected dogs (gsd7/gsd7) should not be bred.
Test Information: This mutation test identifies a single base pair change in the PFKM gene.
Smith, B.F., Stedman, H., Rajpurohit, Y., Henthorn, P.S., Wolfe, J.H., Patterson, D.F., Giger, U.: Molecular basis of canine muscle type phosphofructokinase deficiency Journal of Biological Chemistry 271:20070-20074, 1996. Pubmed reference: 8702726.
Further information is available at the Online Mendelian Inheritance in Animals website.