Glycogen branching enzyme leads to increased osmotic pressure resulting in cellular swelling and death. The tissues most affected by this disease are the liver, heart, and neuromuscular system, areas with the greatest levels of glycogen accumulation. Abnormal glycogen buildup in the liver interferes with liver functioning and can result in an enlarged liver and liver disease. In muscles, the inability of cells to efficiently breakdown glycogen due to the severe reduction or absence of branching can lead to muscle weakness and atrophy. At least three mutations in the GBE1 gene have been found to cause another disease called adult polyglucosan body disease (APBD).
Glycogen storage disease type IV Glycogen storage disease type IV Glycogen storage disease type IV, also known as Andersen’s Disease, is a form of glycogen storage disease, which is caused by an inborn error of metabolism. It is the result of a mutation in the GBE1 gene, which causes a defect in the glycogen branching enzyme. Therefore, glycogen is not made properly and abnormal glycogen molecules accumulate in cells; most severely in cardiac and muscle cells. The severity of this disease varies on the amount of enzyme produced. Glycogen Storage Disease Type IV is autosomal recessive, which means each parent has a mutant copy of