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Disease Profile

Glycogen storage disease type 7

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
<1 / 1 000 000

< 331

US Estimated

< 514

Europe Estimated

Age of onset

Infancy

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ICD-10

E74.0

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Muscle phosphofructokinase deficiency; Tarui disease; GSD7;

Categories

Blood Diseases; Congenital and Genetic Diseases; Metabolic disorders;

Summary

Glycogen storage disease type 7 (GSD7) is an inherited condition in which the body is unable to break down glycogen (a complex sugar) in the muscle cells. Because glycogen is an important source of energy, this can interfere with the normal functioning of muscle cells. The severity of the condition and the associated signs and symptoms vary, but may include muscle weakness and stiffness; painful muscle cramps; nausea and vomiting; and/or myoglobinuria (the presence of myoglobin in the urine) following moderate to strenuous exercise. Symptoms typically resolve with rest. GSD7 is most commonly diagnosed during childhood; however, some affected people may rarely develop symptoms during infancy or later in adulthood. Those who develop the condition during infancy may experience additional symptoms such as hypotonia (poor muscle tone), cardiomyopathy and breathing difficulties that often lead to a shortened lifespan (less than 1 year).[1][2][3] This condition is caused by changes (mutations) in the PFKM gene and is inherited in an autosomal recessive manner.[1] There is no specific treatment for GSD7; however, affected people are generally advised to avoid vigorous exercise and high-carbohydrate meals.[2][3]

Symptoms

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Anemia
Low number of red blood cells or hemoglobin
0001903
Increased muscle glycogen content
0009051
Myotonia
0002486
30%-79% of people have these symptoms
Hyperuricemia
High blood uric acid level
0002149
Muscle weakness
Muscular weakness
0001324
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting

[ more ]

0003202
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance
0000007
Cholelithiasis
Gallstones
0001081
Exercise intolerance
Decreased ability to exercise
Inability to exercise

[ more ]

0003546
Exercise-induced muscle cramps
Exercise-induced muscle cramping
Muscle cramps following exercise
Muscle cramps on exercise
Muscle cramps on exertion
Muscle cramps with exertion

[ more ]

0003710
Exercise-induced myoglobinuria
0008305
Gout
0001997
Hemolytic anemia
0001878
Increased total bilirubin
High bili total
0003573
Jaundice
Yellow skin
Yellowing of the skin

[ more ]

0000952
Reduced erythrocyte 2,3-diphosphoglycerate concentration
0030271
Reticulocytosis
Increased immature red blood cells
Increased number of immature red blood cells

[ more ]

0001923
Variable expressivity
0003828

Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

    Organizations

    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • Genetics Home Reference (GHR) contains information on Glycogen storage disease type 7. This website is maintained by the National Library of Medicine.
      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

        In-Depth Information

        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
          Type VII Glycogen Storage Disease
          Genetics of Glycogen-Storage Disease Type VII
        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Glycogen storage disease type 7. Click on the link to view a sample search on this topic.

          References

          1. Glycogen storage disease type VII. Genetics Home Reference. April 2014; https://ghr.nlm.nih.gov/condition/glycogen-storage-disease-type-vii.
          2. Wayne E Anderson, DO, FAHS, FAAN. Type VII Glycogen Storage Disease. Medscape Reference. August 2014; https://emedicine.medscape.com/article/119947-overview.
          3. Lynne Ierardi-Curto, MD, PhD. Genetics of Glycogen-Storage Disease Type VII. Medscape Reference. October 2013; https://emedicine.medscape.com/article/949388-overview.