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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed January 2014

What is the official name of the GYS2 gene?

The official name of this gene is “glycogen synthase 2.”

GYS2 is the gene's official symbol. The GYS2 gene is also known by other names, listed below.

What is the normal function of the GYS2 gene?

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 sugar levels between meals.

Does the GYS2 gene share characteristics with other genes?

The GYS2 gene belongs to a family of genes called glycosyltransferase group 1 domain containing (glycosyltransferase group 1 domain containing).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the GYS2 gene related to health conditions?

glycogen storage disease type 0 - caused by mutations in the GYS2 gene

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 sugar (hypoglycemia) and nausea as well as other signs and symptoms of GSD 0.

Where is the GYS2 gene located?

Cytogenetic Location: 12p12.2

Molecular Location on chromosome 12: base pairs 21,531,527 to 21,630,773

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The GYS2 gene is located on the short (p) arm of chromosome 12 at position 12.2.

The GYS2 gene is located on the short (p) arm of chromosome 12 at position 12.2.

More precisely, the GYS2 gene is located from base pair 21,531,527 to base pair 21,630,773 on chromosome 12.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about GYS2?

You and your healthcare professional may find the following resources about GYS2 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the GYS2 gene or gene products?

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

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding GYS2?

enzyme ; fasting ; gene ; glucose ; glycogen ; hepatic ; hypoglycemia ; simple sugar

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • 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. (
  • NCBI Gene (
  • Orho M, Bosshard NU, Buist NR, Gitzelmann R, Aynsley-Green A, Blümel 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. (
  • 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. (
  • 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. Epub 2005 Dec 6. Review. (


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 healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: January 2014
Published: February 1, 2016