<unk>  (GSD<unk>  is a rare inherited disorder affecting the glycogen metabolism. In 1956, DH Andersen, an American pathologist and pediatrician reported the first clinical case of the disease. It is caused by mutations in the GBE1 gene, which then results in variable deficiency of glycogen branching enzyme (GBE), an enzyme responsible for the branched structure of glycogen molecules. Due to decreased activity of GBE, abnormal glycogen molecules with less branches is synthesized which then precipitates in various body tissue, especially the liver, muscle, and heart. Clinically, GSD<unk>  manifests as different types; the classic hepatic subtype, and the neuromuscular subtype. Based on clinical features and age of onset, the neuromuscular type can be further divided into four forms including perinatal form, congenital form, late childhood form, and the adult form. The classic hepatic subtype presents with failure to thrive during first few months after birth, and then, progresses to liver dysfunction. Unless a liver transplant is performed, death due to liver cirrhosis occurs by the age of 5 years. The perinatal neuromuscular subtype presents in utero with polyhydramnios, hydrops fetalis, and decreased fetal movement. The congenital neuromuscular subtype presents in the newborn period with severe hypotonia, decreased reflexes, and dilated cardiomyopathy. The childhood neuromuscular subtype may present at any age during childhood with myopathy and cardiomyopathy which progresses to congestive heart failure. The adult neuromuscular form may present as isolated myopathy or adult polyglucosan body disease (APBD). The diagnosis requires demonstration of GBE deficiency in liver, muscle, or skin fibroblasts, and/or gene testing for mutations in GBE1. The management is multidisciplinary, and should be provided by a team comprising of a pediatrician, a cardiologist, a neurologist, a nutritionist, and a geneticist.
Glycogen storage disease type IV
Glycogen storage disease type I CT
Glycogen storage disease type III
Glycogen storage disease type II
Glycogen storage disease type V
Glycogen storage disease type VII
Glycogen storage disease type VI
Glycogen storage disease type XI