A Functional Human Glycogen Debranching Enzyme Encoded by a Synthetic Gene: Its Implications for Glycogen Storage Disease Type III Management

Glycogen Storage Disease type III (GSD III) is a metabolic disorder resulting from a deficiency of the Glycogen Debranching Enzyme (GDE), a large monomeric protein (approximately 170 kDa) with cytoplasmic localization and two distinct enzymatic activities: 4-α-glucantransferase and amylo-α-1,6-glucosidase. Mutations in the Agl gene, with consequent deficiency in GDE, lead to the accumulation of abnormal/toxic glycogen with shorter chains (phosphorylase limit dextrin, PLD) in skeletal and/or heart muscle and/or in the liver. Currently, there is no targeted therapy, and available treatments are symptomatic, relying on specific diets.