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Genetic and Rare Diseases Information Center (GARD)

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Glycogen storage disease type 3

Other Names for this Disease
  • Amylo-1,6-glucosidase deficiency
  • Cori disease
  • Forbes disease
  • Glycogen debrancher deficiency
  • Limit dextrinosis
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Your Question

My son has been diagnosed with GSD type 3 based on liver biopsy. Is there another test to confirm this diagnosis? Are there any treatments available?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

How is glycogen storage disease type 3 diagnosed?

Glycogen storage disease type 3 (GSDIII) should be suspected when three main features are present: hepatomegaly (enlarged liver), ketotic hypoglycemia (low blood sugar accompanied by ketosis), and elevated serum concentration of transaminases (a type of enzyme) and CK. Debranching enzyme activity (which is deficient in individuals with the condition) can be measured in a liver biopsy, but this is now not typically necessary for diagnosis. Genetic testing of the AGL gene, the only gene known to be associated with GSDIII, confirms the diagnosis.[1]
Last updated: 2/13/2012

Is genetic testing available for glycogen storage disease type 3?

Yes. GeneTests lists the names of laboratories that are performing genetic testing for GSDIII. To view the contact information for the clinical laboratories conducting testing, click here.

Please note: Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.
Last updated: 2/13/2012

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 10/18/2013

How might glycogen storage disease type 3 be treated?

There is not currently a cure for for glycogen storage disease type 3 (GSDIII). In some cases, diet therapy is helpful. Strict adherence to a dietary regimen may reduce liver size, prevent hypoglycemia (low blood sugar), help to reduce symptoms, and allow for growth and development.[2] Management typically includes a high-protein diet with cornstarch supplementation to maintain a normal level of glucose in the blood. In infancy, feeding every three to four hours is typically recommended. Toward the end of the first year of life, cornstarch is usually tolerated and can be used to avoid hypoglycemia. A high-protein diet prevents breakdown of muscle protein in times of glucose need and preserves skeletal and cardiac muscles. Skeletal and cardiac myopathies may be improved with high-protein diet and avoiding excessive carbohydrate intake.[1] Liver transplantation may be indicated for patients with hepatic cancers.[2]

Individuals seeking personal treatment advice should speak with their health care provider.
Last updated: 2/13/2012