Learn About Glycogen Storage Disease Type 5

What is the definition of Glycogen Storage Disease Type 5?

Glycogen storage disease type V (also known as GSDV or McArdle disease) is an inherited disorder caused by an inability to break down a complex sugar called glycogen in muscle cells. A lack of glycogen breakdown interferes with the function of muscle cells.

People with GSDV typically experience fatigue, muscle pain, and cramps during the first few minutes of exercise (exercise intolerance). Exercise such as weight lifting or jogging usually triggers these symptoms in affected individuals. The discomfort is generally alleviated with rest. If individuals rest after brief exercise and wait for their pain to go away, they can usually resume exercising with little or no discomfort (a characteristic phenomenon known as "second wind").

Prolonged or intense exercise can cause muscle damage in people with GSDV. About half of people with GSDV experience breakdown of muscle tissue (rhabdomyolysis). In severe episodes, the destruction of muscle tissue releases a protein called myoglobin, which is filtered through the kidneys and released in the urine (myoglobinuria). Myoglobin causes the urine to be red or brown. This protein can also damage the kidneys, and it is estimated that half of those individuals with GSDV who have myoglobinuria will develop life-threatening kidney failure.

The signs and symptoms of GSDV can vary significantly in affected individuals. The features of this condition typically begin in a person's teens or twenties, but they can appear anytime from infancy to adulthood. In most people with GSDV, the muscle weakness worsens over time; however, in about one-third of affected individuals, the muscle weakness is stable. Some people with GSDV experience mild symptoms such as poor stamina; others do not experience any symptoms.

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What are the causes of Glycogen Storage Disease Type 5?

Mutations in the PYGM gene cause GSDV. The PYGM gene provides instructions for making an enzyme called myophosphorylase. This enzyme is found only in muscle cells, where it breaks down glycogen into a simpler sugar called glucose-1-phosphate. Additional steps convert glucose-1-phosphate into glucose, a simple sugar that is the main energy source for most cells.

PYGM gene mutations prevent myophosphorylase from breaking down glycogen effectively. As a result, muscle cells cannot produce enough energy, so muscles become easily fatigued. Reduced energy production in muscle cells leads to the major features of GSDV.

How prevalent is Glycogen Storage Disease Type 5?

GSDV is a rare disorder; however, its prevalence is unknown. In the Dallas-Fort Worth area of Texas, where the prevalence of GSDV has been studied, the condition is estimated to affect 1 in 100,000 individuals.

Is Glycogen Storage Disease Type 5 an inherited disorder?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Who are the top Glycogen Storage Disease Type 5 Local Doctors?
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Universitat Autònoma De Barcelona

Barcelona, CT, ES 

Gisela Gadea-Nogales is in Barcelona, Spain. Gadea-Nogales is rated as an Elite expert by MediFind in the treatment of Glycogen Storage Disease Type 5. She is also highly rated in 8 other conditions, according to our data. Her top areas of expertise are Glycogen Storage Disease Type 5, Pompe Disease, Myoglobinuria Recurrent, and Rhabdomyolysis.

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Highly rated in
11
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Universidad Europea De Madrid

Madrid, MD, ES 

Alejandro Lucia is in Madrid, Spain. Lucia is rated as an Elite expert by MediFind in the treatment of Glycogen Storage Disease Type 5. He is also highly rated in 11 other conditions, according to our data. His top areas of expertise are Glycogen Storage Disease Type 5, Pompe Disease, Myoglobinuria Recurrent, and Rhabdomyolysis.

 
 
 
 
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Elite
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14
conditions

National Hospital For Neurology And Neurosurgery

London, ENG, GB 

Ros Quinlivan is in London, United Kingdom. Quinlivan is rated as an Elite expert by MediFind in the treatment of Glycogen Storage Disease Type 5. They are also highly rated in 14 other conditions, according to our data. Their top areas of expertise are Myoglobinuria Recurrent, Glycogen Storage Disease Type 5, Glycogen Storage Disease Type 13, and Pompe Disease.

What are the latest Glycogen Storage Disease Type 5 Clinical Trials?
MRI in McArdle Disease (Glycogen Storage Disease Type V)
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Coordination of Rare Diseases at Sanford
What are the Latest Advances for Glycogen Storage Disease Type 5?
MCARDLE'S DISEASE AND PHYSICAL ACTIVITY - A MIXED BLESSING.
Data from the European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC).
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Creation and implementation of a European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC registry).