Reviewed June 2014
What is glycogen storage disease type V?
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.
How common is glycogen storage disease type V?
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.
What genes are related to glycogen storage disease type V?
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.
Changes in this gene are associated with glycogen storage disease type V.
How do people inherit glycogen storage disease type V?
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.
Where can I find information about diagnosis or management of glycogen storage disease type V?
These resources address the diagnosis or management of glycogen storage disease type V and may include treatment providers.
- Gene Review: Glycogen Storage Disease Type V (http://www.ncbi.nlm.nih.gov/books/NBK1344)
- Genetic Testing Registry: Glycogen storage disease, type V (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0017924)
- MedlinePlus Encyclopedia: McArdle syndrome (http://www.nlm.nih.gov/medlineplus/ency/article/000329.htm)
You might also find information on the diagnosis or management of glycogen storage disease type V in
Educational resources (http://www.ghr.nlm.nih.gov/condition/glycogen-storage-disease-type-v/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/glycogen-storage-disease-type-v/show/Patient+support).
General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook.
Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).
To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
Where can I find additional information about glycogen storage disease type V?
You may find the following resources about glycogen storage disease type V helpful. These materials are written for the general public.
MedlinePlus - Health information
- Encyclopedia: Fatigue (http://www.nlm.nih.gov/medlineplus/ency/article/003088.htm)
- Encyclopedia: McArdle syndrome (http://www.nlm.nih.gov/medlineplus/ency/article/000329.htm)
- Encyclopedia: Rhabdomyolysis (http://www.nlm.nih.gov/medlineplus/ency/article/000473.htm)
- Health Topic: Metabolic Disorders (http://www.nlm.nih.gov/medlineplus/metabolicdisorders.html)
- Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases (http://rarediseases.info.nih.gov/gard/6528/glycogen-storage-disease-type-5/resources/1)
Educational resources - Information pages
- CLIMB: Glycogen Storage Disease V Information Sheet (http://www.climb.org.uk/IMD/Golf/GlycogenStorageDiseaseV-McArdleDisease.pdf)
- Disease InfoSearch: Glycogen Storage Disease Type 5 (http://www.diseaseinfosearch.org/Glycogen+Storage+Disease+Type+5/3125)
- Madisons Foundation (http://www.madisonsfoundation.org/index.php?option=com_mpower&task=disease&diseaseID=622)
- Merck Manual Home Edition for Patients and Caregivers: Disorders of Carbohydrate Metabolism (http://www.merckmanuals.com/home/childrens_health_issues/hereditary_metabolic_disorders/disorders_of_carbohydrate_metabolism.html)
- Muscular Dystrophy Association: McArdle's Disease (http://mda.org/disease/metabolic-diseases-of-muscle/mcardle-disease)
- Muscular Dystrophy Canada: McArdle's Disease Information Sheet (http://www.muscle.ca/fileadmin/National/Muscular_Dystrophy/Disorders/McArdles_E.pdf)
- Orphanet: Glycogen storage disease due to muscle glycogen phosphorylase deficiency (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=368)
- The Swedish Information Centre for Rare Diseases (http://www.socialstyrelsen.se/rarediseases/mcardledisease)
- Washington University, St. Louis: Neuromuscular Disease Center (http://neuromuscular.wustl.edu/msys/glycogen.html)
Patient support - For patients and families
- CLIMB: Children Living with Inherited Metabolic Diseases (http://www.climb.org.uk/)
- National Organization for Rare Disorders (NORD) (http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/395/viewAbstract)
- The Association for Glycogen Storage Disease (UK) (http://www.agsd.org.uk/tabid/1137/default.aspx)
- The Association for Glycogen Storage Disease (US) (http://www.agsdus.org/html/typevgsd.html)
- University of Kansas Medical Center Resource List (http://www.kumc.edu/gec/support/glycogen.html)
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
- Gene Reviews - Clinical summary (http://www.ncbi.nlm.nih.gov/books/NBK1344)
Genetic Testing Registry - Repository of genetic test information
- Genetic Testing Registry: Glycogen storage disease, type V (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0017924)
- ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/ct2/results?cond=%22glycogen%20storage%20disease%20type%20V%22)
- OMIM - Genetic disorder catalog (http://omim.org/entry/232600)
What other names do people use for glycogen storage disease type V?
- glycogenosis 5
- glycogen storage disease type 5
- GSD type V
- GSD V
- McArdle disease
- McArdle's disease
- McArdle syndrome
- McArdle type glycogen storage disease
- muscle glycogen phosphorylase deficiency
- muscle phosphorylase deficiency
- myophosphorylase deficiency
- PYGM deficiency
For more information about naming genetic conditions, see the Genetics Home Reference
Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide)
How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
What if I still have specific questions about glycogen storage disease type V?
Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).
What glossary definitions help with understanding glycogen storage disease type V?
autosomal recessive ;
muscle cells ;
simple sugar ;
You may find definitions for these and many other terms in the Genetics Home Reference
- Aquaron R, Bergé-Lefranc JL, Pellissier JF, Montfort MF, Mayan M, Figarella-Branger D, Coquet M, Serratrice G, Pouget J. Molecular characterization of myophosphorylase deficiency (McArdle disease) in 34 patients from Southern France: identification of 10 new mutations. Absence of genotype-phenotype correlation. Neuromuscul Disord. 2007 Mar;17(3):235-41. Epub 2007 Feb 26. (http://www.ncbi.nlm.nih.gov/pubmed/17324573?dopt=Abstract)
- Bruno C, Cassandrini D, Martinuzzi A, Toscano A, Moggio M, Morandi L, Servidei S, Mongini T, Angelini C, Musumeci O, Comi GP, Lamperti C, Filosto M, Zara F, Minetti C. McArdle disease: the mutation spectrum of PYGM in a large Italian cohort. Hum Mutat. 2006 Jul;27(7):718. (http://www.ncbi.nlm.nih.gov/pubmed/16786513?dopt=Abstract)
- Deschauer M, Morgenroth A, Joshi PR, Gläser D, Chinnery PF, Aasly J, Schreiber H, Knape M, Zierz S, Vorgerd M. Analysis of spectrum and frequencies of mutations in McArdle disease. Identification of 13 novel mutations. J Neurol. 2007 Jun;254(6):797-802. Epub 2007 Apr 3. (http://www.ncbi.nlm.nih.gov/pubmed/17404776?dopt=Abstract)
- Gurgel-Giannetti J, Nogales-Gadea G, van der Linden H Jr, Bellard TM, Brasileiro Filho G, Giannetti AV, de Castro Concentino EL, Vainzof M. Clinical and molecular characterization of McArdle's disease in Brazilian patients. Neuromolecular Med. 2013 Sep;15(3):470-5. doi: 10.1007/s12017-013-8233-2. Epub 2013 May 8. (http://www.ncbi.nlm.nih.gov/pubmed/23653251?dopt=Abstract)
- Lucia A, Nogales-Gadea G, Pérez M, Martín MA, Andreu AL, Arenas J. McArdle disease: what do neurologists need to know? Nat Clin Pract Neurol. 2008 Oct;4(10):568-77. doi: 10.1038/ncpneuro0913. Review. (http://www.ncbi.nlm.nih.gov/pubmed/18833216?dopt=Abstract)
- Lucia A, Ruiz JR, Santalla A, Nogales-Gadea G, Rubio JC, García-Consuegra I, Cabello A, Pérez M, Teijeira S, Vieitez I, Navarro C, Arenas J, Martin MA, Andreu AL. Genotypic and phenotypic features of McArdle disease: insights from the Spanish national registry. J Neurol Neurosurg Psychiatry. 2012 Mar;83(3):322-8. doi: 10.1136/jnnp-2011-301593. Epub 2012 Jan 16. (http://www.ncbi.nlm.nih.gov/pubmed/22250184?dopt=Abstract)
- Rubio JC, Garcia-Consuegra I, Nogales-Gadea G, Blazquez A, Cabello A, Lucia A, Andreu AL, Arenas J, Martin MA. A proposed molecular diagnostic flowchart for myophosphorylase deficiency (McArdle disease) in blood samples from Spanish patients. Hum Mutat. 2007 Feb;28(2):203-4. (http://www.ncbi.nlm.nih.gov/pubmed/17221871?dopt=Abstract)
The resources on this site should not be used as a substitute for
professional medical care or advice. Users seeking information about
a personal genetic disease, syndrome, or condition should consult with a qualified
See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.