Glycogen grams of glucose are present in the blood of humans at all times; in fasted individuals, blood glucose is maintained constant at this level at the expense of glycogen stores in the liver and skeletal muscle. Glycogen stores in skeletal muscle serve as a form of energy storage for the muscle itself; however, the breakdown of muscle glycogen impedes muscle glucose uptake, thereby increasing the amount of blood glucose available for use in other tissues. Liver glycogen stores serve as a store of glucose for use throughout the body, particularly the central nervous system. The human brain consumes approximately 60%
Adult polyglucosan body disease People with adult polyglucosan body disease typically first experience signs and symptoms related to the condition between ages 30 and 60. APBD is an autosomal recessive disorder that is caused when a person inherits genes from both parents containing one or more loss-of-function mutations in the gene "GBE1" which encodes for glycogen branching enzyme, also called 1,4-alpha-glucan-branching enzyme. The "GBE1" gene provides instructions for making the glycogen branching enzyme. This enzyme is involved in the production of a complex sugar called glycogen, which is a major source of stored energy in the body. Most "GBE1" gene mutations result in a