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Children's Health

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Glycogen Storage Disease Type V

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.


Disorder Subdivisions

  • None

General Discussion

Glycogen storage disease type V (McArdle Disease or GSD-V) is one of several inherited glycogen storage diseases all of which are caused by failures of specific enzymes required for the storage of energy-supplying glycogen. In the case of GSD-V, symptoms are caused by the lack of the crucial enzyme muscle phosphorylase (myophosphorylase). This enzyme is needed for the breakdown of glycogen (the body's form of stored energy) into sugar (glucose) in muscle tissues. All of the glycogen storage diseases are characterized by the inability to break down glycogen, but in each case this occurs for a different reason. Unlike most of the other GSDs, type V has two autosomal recessive forms, a childhood-onset form and an adult-onset form. In addition, there is a much more rare autosomal dominant form of GSD-V. The clinical features of GSD-V are exercise intolerance, muscle cramping, and dark, burgundy-colored urine due to the presence of myoglobin (myoglobinuria).


CLIMB (Children Living with Inherited Metabolic Diseases)
Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174

Association for Glycogen Storage Disease
P.O. Box 896
Durant, IA 52747
Tel: (563)514-4022
Fax: (563)514-4022

Vaincre Les Maladies Lysosomales
2 Ter Avenue
Massy, 91300
Tel: 0169754030
Fax: 0160111583

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
31 Center Drive, MSC 2560
Bethesda, MD 20892-2560
Tel: (301)496-3583

Association for Glycogen Storage Disease (UK) Ltd
Old Hambledon Racecourse
Sheardley Lane, Droxford
Hampshire, SO32 3QY
United Kingdom
Tel: 03001232790

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
TDD: (888)205-3223

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: 5/27/2008
Copyright 1987, 1989, 1992, 1993, 1995, 2003 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: May 28, 2015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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