glycogen synthase 2
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.
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.
- glycogen [starch] synthase, liver
- glycogen synthase 2 (liver)
- liver glycogen synthase
- liver glycogen synthase 2