Which enzyme is deficient in Cori's disease?

Cori's disease, also known as glycogen storage disease type III, is characterized by a deficiency in the debranching enzyme, which is responsible for the proper metabolism of glycogen. This enzyme plays a crucial role in the breakdown of glycogen by facilitating the removal of branches from the glycogen molecule during glycogenolysis. When this enzyme is deficient, glycogen cannot be efficiently broken down, leading to the accumulation of abnormal glycogen structures, often referred to as limit dextrins.

The clinical manifestations of Cori's disease include hypoglycemia, hepatomegaly, and muscle weakness. The inability to properly process glycogen results in reduced glucose availability during fasting states, contributing to the hypoglycemia seen in affected individuals. Additionally, symptoms can sometimes resemble those of von Gierke disease, where glucose-6-phosphatase is deficient, but the key distinguishing feature in Cori's disease is the specific deficiency of the debranching enzyme.

Understanding the biology of glycogen metabolism and the role of various enzymes helps in recognizing how deficiencies lead to specific clinical presentations. In the case of Cori's disease, the debranching enzyme's function is crucial, and its absence directly leads to the characteristic glycogen storage issues