Glycogen storage disease type IV the gene but show no symptoms of the disease. It affects 1 in 800,000 individuals worldwide, with 3% of all Glycogen Storage Diseases being type IV. It is a result of the absence of the glycogen branching enzyme, which is critical in the production of glycogen. This leads to very long unbranched glucose chains being stored in glycogen. The long unbranched molecules have a low solubility which leads to glycogen precipitation in the liver. These deposits subsequently build up in the body tissue, especially the heart and liver. The inability to breakdown glycogen in muscle cells causes muscle weakness. The
Glycogen found that muscular tissue also contains glycogen. The empirical formula for glycogen of () was established by Kekulé in 1858. Glycogen synthesis is, unlike its breakdown, endergonic—it requires the input of energy. Energy for glycogen synthesis comes from uridine triphosphate (UTP), which reacts with glucose-1-phosphate, forming UDP-glucose, in a reaction catalysed by UTP—glucose-1-phosphate uridylyltransferase. Glycogen is synthesized from monomers of UDP-glucose initially by the protein glycogenin, which has two tyrosine anchors for the reducing end of glycogen, since glycogenin is a homodimer. After about eight glucose molecules have been added to a tyrosine residue, the enzyme glycogen synthase progressively lengthens