The symptoms of glycogen storage disease can vary based on the type and even from person to person with the same type. Symptoms of GSD type 1 (the most common type) usually begin at three to four months of age. But symptoms of other types can develop later in life.
The two most common symptoms are low blood sugar (hypoglycemia) and/or getting tired easily from physical activity (exercise intolerance).
Low blood sugar happens when your blood glucose is below 70 mg/dL. Symptoms include:
Other symptoms of GSD may include:
Inherited genetic mutations (changes) that affect the function of enzymes necessary for glycogen storage and use cause GSD. A child inherits the mutations from their biological parents.
Most GSDs have autosomal recessive inheritance, meaning both parents have to pass on the mutation for the child to get the condition.
But a few types, like GSD type IX, have an X-linked inheritance. This means that your X chromosome carries the mutation. A man who has the mutation will have the condition because they carry only one X chromosome. A woman who has the mutation in one gene, with a normal gene on the other X chromosome, generally doesn’t have the condition.
To diagnose glycogen storage disease, your child’s healthcare provider will likely recommend several tests. Since GSD is rare, it can take time to rule out other conditions and figure out the specific type of GSD. The tests may include:
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Although specific genetic testing is available for diagnosing most types of GSD, your child’s provider may want to perform a muscle or liver biopsy to confirm the diagnosis.
There’s no cure for glycogen storage disease, so treatment is based on managing symptoms. Treatment varies based on the type of GSD you have. Examples of treatment include:
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Some GSDs (like GSD type II) can be treated with enzyme replacement therapy (ERT). This is usually an IV infusion. There’s ongoing research on using ERT with other forms of GSDs.
If you have severe liver damage from GSD, a liver transplant may become necessary.
With early diagnosis and proper management, the prognosis (outlook) for people with most GSDs is good. But some types of GSD are difficult to manage. Your healthcare provider can give you a better idea of what to expect.
GSDs can cause several complications depending on:
For example, possible complications of untreated GSD type 1 include:
The life expectancy for glycogen storage disease varies based on the type, how early it’s diagnosed and how well it’s managed. Some types are fatal in infancy while others have relatively normal life expectancies. Your healthcare provider will be able to give you the best idea of what to expect.
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As glycogen storage diseases are genetic (inherited) conditions, there’s nothing you can do to prevent them.
If you have a biological family member with GSD, you may want to consider genetic counseling if you’re thinking of having a biological child to see if you’re a carrier of the genetic mutation.
Talk to your healthcare provider if you or your child experiences muscle weakness or persistent symptoms of low blood sugar.
Glycogen storage diseases are rare and complex. So, it’s best to find a healthcare provider who knows about the condition and how to treat it, if possible. Your child’s healthcare team will be with you every step of the way to support you and decide the best treatment for them.
Learning your child has rare glycogen storage disease can be overwhelming. Cleveland Clinic Children's experts are here to help treat and manage your child’s GSD.

Last reviewed on 06/26/2023.
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