Glycogen Storage Disease Type V

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Glycogen Storage Disease Type V is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Glycogenosis Type V
  • Glycogen Storage Disease type V (GSD-V)
  • GSD-V
  • McArdle Disease
  • Myophosphorylase Deficiency
  • Muscle Glycogen Phosphorylase Deficiency

Disorder Subdivisions

  • None

General Discussion

Glycogen storage disease type V (GSD-V or McArdle disease) is the most common disorder of skeletal muscle carbohydrate metabolism and one of most frequent genetic myopathies (prevalence ~1:100000). Twelve different types of glycogen storage disease have been described (type 0, I-VII, IX, XI-XIII), which result from defects in glycogen synthesis and breakdown principally in the muscle and liver, although other tissues can also be affected. GSD-V is caused by the lack of the muscle glycogen phosphorylase (myophosphorylase) enzyme. Although symptoms typically begin during the first ten years of life, the age of diagnosis can vary significantly. The characteristic symptoms of GSD-V are exercise intolerance, myalgia (muscle pain), muscle stiffness and contractures, quick fatigue as well as hyperCKemia and myoglobinuria (dark, burgundy-colored urine due to the presence of myoglobin, a protein found in heart and muscles). These symptoms are usually caused by isometric or uninterrupted aerobic exercise. Currently, there is no cure for GSD-V. To manage GSD-V, medical professionals suggest that people affected avoid intense exercise and a completely inactive lifestyle, but do engage in consistent, reasonable aerobic exercise.

Supporting Organizations

Association for Glycogen Storage Disease

P.O. Box 896
Durant, IA 52747
Tel: (563)514-4022
Fax: (563)514-4022

Association for Glycogen Storage Disease (UK) Ltd

Old Hambledon Racecourse
Sheardley Lane, Droxford
Hampshire, SO32 3QY
United Kingdom
Tel: 3001232790

CLIMB (Children Living with Inherited Metabolic Diseases)

Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

Muscular Dystrophy Association

3300 East Sunrise Drive
Tucson, AZ 85718-3208
Tel: (520)529-2000
Fax: (520)529-5300
Tel: (800)572-1717

NIH/National Institute of Diabetes, Digestive & Kidney Diseases

Office of Communications & Public Liaison
Bldg 31, Rm 9A06
Bethesda, MD 20892-2560
Tel: (301)496-3583

Vaincre Les Maladies Lysosomales

2 Ter Avenue
Massy, 91300
Tel: 169754030
Fax: 160111583

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated:  1/24/1970
Copyright  2015 National Organization for Rare Disorders, Inc.