Glycogen storage disease VII / PFK deficiency (PFKM-related) - Dog

What does this test analyse?

This genetic test analyses the PFKM c.2228G>A variant in the dog. The disorder is known as Glycogen storage disease VII / PFK deficiency, phosphofructokinase deficiency, PFK deficiency or Tarui-like GSD VII, inherited glycogen storage, glycogen storage disease and a metabolic disorder of energy or glucose metabolism.

PFKM encodes muscle phosphofructokinase, a key enzyme in glycolysis in muscle cells and red blood cells. When this process is disrupted, glycogen or abnormal glycogen-like material can accumulate in tissues with high energy demand. This explains why affected dogs may develop problems involving muscle function, exercise, blood cells, liver, kidneys or heart, depending on the specific form. Affected dogs can develop muscle cramps, exercise intolerance, muscle breakdown and acute hemolytic crises after exercise, excitement or heat. Lethargy, fever, jaundice and dark brown to purple urine can occur.

Practical value of this test

The test is important for breeders and owners who want to manage a serious autosomal recessive risk within a breed line before matings are planned. Carriers are usually healthy or not clearly recognisable, but can pass the variant on unnoticed. By testing breeding dogs beforehand, a carrier can be paired responsibly with a clear partner and carrier-to-carrier matings can be avoided. This is especially useful in sporting or working lines because exercise and heat can trigger clinical crises.

• Clear: the tested variant was not detected.
• Carrier: one copy of the variant is present and can be passed on.
• Affected genotype: two copies cause the tested recessive form.