BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuType V glycogen storage diseaseMyophosphorylase deficiency; Muscle glycogen phosphorylase deficiency; PYGM deficiencyType V (five) glycogen storage disease (GSD V) is a rare inherited condition in which the body is not able to break down glycogen. Glycogen is an important source of energy that is stored in all tissues, especially in the muscles and liver.GSD V is also called McArdle disease. Causes GSD V is caused by a flaw in the gene that makes an enzyme called muscle glycogen phosphorylase. As a result, the body cannot break down glycogen in the muscles.EnzymeEnzymes are complex proteins that cause a specific chemical change in all parts of the body. For example, they can help break down the foods we eat ...Read Article Now Book Mark Article GSD V is an autosomal recessive genetic disorder. This means to have the disorder, you must receive a copy of the nonworking gene from both parents. A person who receives a nonworking gene from only one parent usually does not develop this syndrome. A family history of GSD V increases the risk.Autosomal recessiveAutosomal recessive is one of several ways that a trait, disorder, or disease can be passed down through families. An autosomal recessive disorder me...Read Article Now Book Mark Article Symptoms Symptoms commonly start during early childhood. But, it may be difficult to separate these symptoms from those of normal childhood. Diagnosis may not occur until a person is over 20 or 30 years old. Burgundy-colored urine (myoglobinuria) Fatigue Exercise intolerance, poor stamina Muscle cramps Muscle pain Muscle painMuscle aches and pains are common and can involve more than one muscle. Muscle pain also can involve ligaments, tendons, and fascia. Fascias are th...Read Article Now Book Mark Article Muscle stiffness Muscle weakness Exams and Tests The following tests may be performed:Electromyography (EMG) Electromyography (EMG)Electromyography (EMG) is a test that checks the health of the muscles and the nerves that control the muscles.Read Article Now Book Mark Article Genetic testing Lactic acid in blood Lactic acid in bloodLactic acid is mainly produced in muscle cells and red blood cells. It forms when the body breaks down carbohydrates to use for energy when oxygen l...Read Article Now Book Mark Article MRI MRIA magnetic resonance imaging (MRI) scan is an imaging test that uses powerful magnets and radio waves to create pictures of the body. It does not us...Read Article Now Book Mark Article Muscle biopsy Muscle biopsyA muscle biopsy is the removal of a small piece of muscle tissue for examination.Read Article Now Book Mark Article Myoglobin in urine Myoglobin in urineThe myoglobin urine test is done to detect the presence of myoglobin in urine. Myoglobin can also be measured with a blood test.Read Article Now Book Mark Article Plasma ammonia Serum creatine kinaseSerum creatine kinaseCreatine phosphokinase (CPK) is an enzyme in the body. It is found mainly in the heart, brain, and skeletal muscle. This article discusses the test...Read Article Now Book Mark Article Treatment There is no specific treatment.The health care provider may suggest the following to stay active and healthy and prevent symptoms:Be aware of your physical limitations. Before exercising, warm up gently. Avoid exercising too hard or too long. Eat enough protein.Ask your provider if it's a good idea to eat some sugar before exercising. This may help prevent muscle symptoms.If you need to have surgery, ask your provider if it's OK for you to have general anesthesia. Support Groups More information and support for people with type V glycogen storage condition and their families can be found at:Association for Glycogen Storage Disease -- www.agsdus.org National Organization for Rare Disease Disorders -- rarediseases.info.nih.gov/diseases/6528/glycogen-storage-disease-type-5 Outlook (Prognosis) People with GSD V can live a normal life by managing their diet and physical activity. Possible Complications Exercise may produce muscle pain, or even a breakdown of skeletal muscle (rhabdomyolysis). This condition is associated with burgundy-colored urine and a risk for kidney failure if it is severe.RhabdomyolysisRhabdomyolysis is the breakdown of muscle tissue that leads to the release of muscle fiber contents into the blood. These substances are harmful to ...Read Article Now Book Mark Article Kidney failureAcute kidney failure is the rapid (less than 2 days) loss of your kidneys' ability to remove waste and help balance fluids and electrolytes in your b...Read Article Now Book Mark Article When to Contact a Medical Professional Contact your provider if you have repeated episodes of sore or cramped muscles after exercise, especially if you also have burgundy or pink urine.Consider genetic counseling if you have a family history of GSD V.Open ReferencesReferencesBrandow AM. Enzymatic defects. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 490.Weinstein DA. Glycogen storage diseases. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 196.Williams LM, Mcdonald CM. Myopathic disorders. In: Cifu DX, ed. Braddom's Physical Medicine & Rehabilitation. 6th ed. Philadelphia, PA: Elsevier; 2021:chap 42.AllVideoImagesTogA Closer Look Cirrhosis(In-Depth)Related Information Autosomal recessive(Special Topic)Rhabdomyolysis(Condition)Acute kidney failure(Condition) Review Date: 11/1/2021 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- © 1997- All rights reserved. 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