Glycogen Storage Disease Type V
NORD gratefully acknowledges Megan Usovsky, NORD Editorial Intern from the University of Notre Dame, and Tomàs Pinós, PhD, Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d’Hebron, Institut de Recerca, Universitat Autònoma de Barcelona and Centre for Biomedical Network Research on Rare Diseases , Instituto de Salud Carlos III, for assistance in the preparation of this report.
Synonyms of Glycogen Storage Disease Type V
- Glycogenosis Type V
- Glycogen Storage Disease type V (GSD-V)
- McArdle Disease
- Myophosphorylase Deficiency
- Muscle Glycogen Phosphorylase Deficiency
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.
NORD Member Organizations
1987, 1989, 1992, 1993, 1995, 2003, 2015
The information in NORD’s Rare Disease Database is for educational purposes only and is not intended to replace the advice of a physician or other qualified medical professional.
The content of the website and databases of the National Organization for Rare Disorders (NORD) is copyrighted and may not be reproduced, copied, downloaded or disseminated, in any way, for any commercial or public purpose, without prior written authorization and approval from NORD. Individuals may print one hard copy of an individual disease for personal use, provided that content is unmodified and includes NORD’s copyright.
National Organization for Rare Disorders (NORD)
55 Kenosia Ave., Danbury CT 06810 • (203)744-0100