GSD13 is also known as muscle beta-enolase deficiency.
As at as 2020 we knew of just five cases in the world, so very little is known about it as yet.
Estimated cases diagnosed worldwide: <10.



Muscle pain and fatigue during intense activity, normal baseline CK, rhabdomyolysis.




Early and adult onset.


Skeletal muscle.


No specific treatment. Avoid anaerobic activity.


Good with avoidance of intense exercise.

IAMGSD would welcome hearing from patients or doctors who could help us to improve and expand our information on this extremely rare muscle GSD.


Here you can read here the abstracts of reports on the early cases that have been diagnosed. It appears that patients may be less affected than those with McArdle disease, yet can experience rhabdomyolysis and myoglobinuria. The milder symptoms may be due to some residual enzyme activity - described as 10% to 20% in the cases so far reported.

First ever report of GSD13, in Italy.

Further cases reported in the UK and Italy.


At the present time it is considered that it is a sensible precaution to follow the same advice about avoiding rhabdomyolysis as is given for McArdle disease (GDSD5). In addition, the same advice applies for when to attend hospital in the event of a strong cramp or contracture

101 Tips book for McArdle disease.

Medical emergency guidance for McArdle Disease. 


It is very likely that with the advent of Next Generation Sequencing and a gene panel for conditions which can be the cause of rhabdomyolysis, more cases of GSD13 will be identified. As understanding of the condition grows, so IAMGSD will be able to offer better support for this extremely rare muscle GSD.

What is IamGSD?

We are a patient-led international group encouraging efforts by research and medical professionals, national support groups and individual patients worldwide.

What is Muscle GSD?

Human bodies make glucose from carbohydrates. Excess glucose is stored as glycogen in our muscles and liver. Muscle glycogen storage disease is when our muscles cannot convert their glycogen back into glucose to power our muscles.

Muscle GSDs links
If you have another muscle GSD please contact us.

Site updated: 04/2021.

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