GBE1

The protein encoded by this gene is a glycogen branching enzyme that catalyzes the transfer of alpha-1,4-linked glucosyl units from the outer end of a glycogen chain to an alpha-1,6 position on the same or a neighboring glycogen chain. Branching of the chains is essential to increase the solubility of the glycogen molecule and, consequently, in reducing the osmotic pressure within cells. Highest level of this enzyme are found in liver and muscle. Mutations in this gene are associated with glycogen storage disease IV (also known as Andersen's disease).

Full Name

1,4-Alpha-Glucan Branching Enzyme 1

Function

Required for normal glycogen accumulation (PubMed:8463281, PubMed:26199317, PubMed:8613547).

The alpha 1-6 branches of glycogen play an important role in increasing the solubility of the molecule (Probable).

Biological Process

Carbohydrate metabolic process Source: GO_Central
Generation of precursor metabolites and energy Source: ProtInc
Glycogen biosynthetic process Source: UniProtKB
Glycogen metabolic process Source: ProtInc
Negative regulation of neuron apoptotic process Source: Ensembl

Cellular Location

Cytosol; Extracellular exosome; Cytoplasm

Involvement in disease

Glycogen storage disease 4 (GSD4):
A metabolic disorder characterized by the accumulation of an amylopectin-like polysaccharide. The typical clinical manifestation is liver disease of childhood, progressing to lethal hepatic cirrhosis. Most children with this condition die before two years of age. However, the liver disease is not always progressive. No treatment apart from liver transplantation has been found to prevent progression of the disease. There is also a neuromuscular form of glycogen storage disease type 4 that varies in onset (perinatal, congenital, juvenile, or adult) and severity. Neuromuscular perinatal glycogen storage disease type 4 is associated with non-immune hydrops fetalis, a generalized edema of the fetus with fluid accumulation in the body cavities due to non-immune causes. Non-immune hydrops fetalis is not a diagnosis in itself but a symptom, a feature of many genetic disorders, and the end-stage of a wide variety of disorders.
Polyglucosan body neuropathy, adult form (APBN):
A late-onset, slowly progressive disorder affecting the central and peripheral nervous systems. Patients typically present after age 40 years with a variable combination of cognitive impairment, pyramidal tetraparesis, peripheral neuropathy, and neurogenic bladder. Other manifestations include cerebellar dysfunction and extrapyramidal signs. The pathologic hallmark of APBN is the widespread accumulation of round, intracellular polyglucosan bodies throughout the nervous system, which are confined to neuronal and astrocytic processes.