Glycogen storage disease type IV is an inherited glycogen storage disorder caused by deficient activity of the glycogen-branching enzyme, resulting in accumulation of abnormal glycogen in the liver, muscle, or other tissues.
There are various types of glycogen storage disease type IV, ranging in severity, but in most cases, symptoms arise in the first few months of life, and include failure to grow and gain weight (failure to thrive) and an abnormal enlargement of the liver and spleen (hepatosplenomegaly). Children with this disorder often develop a form of liver disease called cirrhosis, as well as high blood pressure in the vein that supplies blood to the liver. In the more severe cases, children may die of liver failure in early childhood. There is no consensus treatment for this condition other than treating the specific symptoms that are apparent in each individual.
This condition is caused by pathogenic (disease-causing) variants in the GBE1 gene. This disorder exhibits autosomal recessive inheritance, which means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a higher risk of carrying the disease, with a carrier frequency of 1 in 68. Carriers typically do not experience any signs or symptoms of the disease.
Other names for this condition include GBE1-related conditions, Andersen disease, Brancher deficiency, and amylopectinosis.