Glycogen storage disease type IX with enlarged livers. Glycogen storage disease type IX Glycogen storage disease type IX is a hereditary deficiency of glycogen phosphorylase kinase B that affects the liver and skeletal muscle tissue. It is inherited in an X-linked or autosomal recessive manner. The signs and symptoms in glycogen storage disease type IX include: Most of these signs and symptoms diminish as adulthood sets in. Glycogen storage disease type IX can be inherited via: The diagnosis of glycogen storage disease IX consists of the following: There are two types of this inherited condition, "glycogen storage disease IXa1" and "glycogen storage disease IXa2" that
Glycogen phosphorylase Glycogen phosphorylase is regulated by both allosteric control and by phosphorylation. Hormones such as epinephrine, insulin and glucagon regulate glycogen phosphorylase using second messenger amplification systems that are linked to G proteins. Glucagon activates adenylate cyclase through a seven transmembrane receptor coupled to G which, in turn, activates adenylate cyclase to increase intracellular concentrations of cAMP. cAMP binds to and releases an active form of protein kinase A (PKA). Next, PKA phosphorylates phosphorylase kinase, which, in turn, phosphorylates glycogen phosphorylase b, transforming it into the active glycogen phosphorylase a. This phosphorylation is added onto the glycogen phosphorylase b serine 14.