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GYS2 gene

glycogen synthase 2

Normal Function

The GYS2 gene provides instructions for making an enzyme called liver glycogen synthase. Liver glycogen synthase is produced solely in liver cells, where it helps form the complex sugar glycogen by linking together molecules of the simple sugar glucose. Glucose that is taken in from food is stored in the body as glycogen, which is a major source of energy. Glycogen that is stored in the liver can be broken down rapidly when glucose is needed to maintain normal blood glucose levels between meals.

Health Conditions Related to Genetic Changes

Glycogen storage disease type 0

Approximately 20 mutations in the GYS2 gene have been found to cause a form of glycogen storage disease type 0 (GSD 0) that affects the liver. Most GYS2 gene mutations that cause this condition lead to a lack of functional glycogen synthase, resulting in a complete absence of glycogen in liver cells. Normally, glycogen is formed from the leftover glucose that is not immediately used by cells after glucose is consumed during meals. In people with GSD 0, who cannot form glycogen, the extra glucose is released by the body. As a result, people with this condition have no stored energy during long periods without food (fasting). During these periods, affected individuals may develop low blood glucose (hypoglycemia) and nausea as well as other signs and symptoms of GSD 0.

More About This Health Condition

Other Names for This Gene

  • glycogen [starch] synthase, liver
  • glycogen synthase 2 (liver)
  • liver glycogen synthase
  • liver glycogen synthase 2

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Bachrach BE, Weinstein DA, Orho-Melander M, Burgess A, Wolfsdorf JI. Glycogen synthase deficiency (glycogen storage disease type 0) presenting with hyperglycemia and glucosuria: report of three new mutations. J Pediatr. 2002 Jun;140(6):781-3. doi: 10.1067/mpd.2002.124317. Citation on PubMed
  • Orho M, Bosshard NU, Buist NR, Gitzelmann R, Aynsley-Green A, Blumel P, Gannon MC, Nuttall FQ, Groop LC. Mutations in the liver glycogen synthase gene in children with hypoglycemia due to glycogen storage disease type 0. J Clin Invest. 1998 Aug 1;102(3):507-15. doi: 10.1172/JCI2890. Citation on PubMed or Free article on PubMed Central
  • Soggia AP, Correa-Giannella ML, Fortes MA, Luna AM, Pereira MA. A novel mutation in the glycogen synthase 2 gene in a child with glycogen storage disease type 0. BMC Med Genet. 2010 Jan 5;11:3. doi: 10.1186/1471-2350-11-3. Citation on PubMed or Free article on PubMed Central
  • Weinstein DA, Correia CE, Saunders AC, Wolfsdorf JI. Hepatic glycogen synthase deficiency: an infrequently recognized cause of ketotic hypoglycemia. Mol Genet Metab. 2006 Apr;87(4):284-8. doi: 10.1016/j.ymgme.2005.10.006. Epub 2005 Dec 6. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.