Glycogen storage disease Ia / von Gierke disease (G6PC-related) - Maltese

What does this test analyse?

This genetic test analyses the G6PC c.450G>C variant in the Maltese. The disorder is known as Glycogen storage disease Ia / von Gierke disease, GSD1a, glucose-6-phosphatase deficiency or von Gierke disease, inherited glycogen storage, glycogen storage disease and a metabolic disorder of energy or glucose metabolism.

G6PC encodes glucose-6-phosphatase, the enzyme needed to make stored energy available as glucose. 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 recurrent hypoglycemia, weakness, tremors, confusion, seizures, loss of consciousness, poor growth, enlarged liver or kidneys, high lipid levels, high uric acid and urinary stones.

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. The test is particularly valuable because carriers can appear normal, while affected puppies can develop severe metabolic problems.

• 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.