Cori's disease results from a deficiency in which enzyme?

Cori's disease, also known as glycogen storage disease type III, is caused by a deficiency in the debranching enzyme. This enzyme is essential for the complete breakdown of glycogen during the process of glycogenolysis, where glycogen is converted into glucose for energy. Normally, the debranching enzyme facilitates the removal of branches in the glycogen structure, allowing glycogen phosphorylase to work effectively on straight-chain glucose units.

In Cori's disease, the absence or malfunction of this enzyme leads to an accumulation of abnormal glycogen that has short outer branches, known as "limit dextrin." Patients with this condition experience symptoms such as hypoglycemia, muscle weakness, and cardiomyopathy due to the inability to properly mobilize glucose from glycogen stores.

The other enzymes listed relate to different glycogen storage diseases. The branching enzyme is associated with Andersen's disease, glycogen phosphorylase deficiency is related to McArdle's disease, and glucose-6-phosphatase deficiency causes Von Gierke's disease. Each of these conditions has its own distinct biochemical pathways and clinical features, which differentiates them from Cori's disease and further emphasizes the role of the debranching enzyme in this specific condition