What type of enzyme deficiency is associated with Cori / Forbes Disease?

Cori / Forbes Disease, also known as Cori disease, is primarily characterized by a deficiency in a specific enzyme known as the debranching enzyme. This enzyme is crucial for the normal metabolism of glycogen, which is the stored form of glucose in the body. The debranching enzyme plays a vital role in the breakdown of glycogen, especially in the removal of branches in the glycogen molecule, allowing for complete mobilization of glucose.

In Cori disease, the deficiency of this debranching enzyme leads to abnormal glycogen accumulation, characterized by short outer chains and an incomplete breakdown of glycogen, resulting in various symptoms such as hypoglycemia, muscle weakness, and spenomegaly. This enzymatic dysfunction clearly delineates Cori disease from other glycogen storage diseases that do not involve the same type of enzyme or metabolic pathway.

Other enzyme deficiencies mentioned in the options are associated with different metabolic conditions. Glycogen branching enzyme deficiency pertains to Andersen's disease, acid alpha-glucosidase deficiency relates to Pompe disease, and fumarylacetoacetase deficiency is linked to tyrosinemia type I. Each of these conditions has distinct etiologies and clinical presentations, confirming that the debranching enzyme deficiency is