Glycogen storage disease type IV

 Glycogen storage disease type IV is a very rare hereditary metabolic disorder. It is also known as:-
 * Glycogenosis type IV,
 * Andersen's disease,
 * Glycogen Branching Enzyme Deficiency (GBED),
 * polyglucosan body disease.
 * Amylopectinosis

Human pathology
It is a result of the absence of the glycogen branching enzyme amylo-1,4-1,6 transglucosidase, which is critical in the production of glycogen. This leads to very long unbranched glucose chains being stored in glycogen. The long unbranched molecules (known as amylopectin) 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 end result is liver failure and eventual death occurring in the first year of life.