Cori's disease, also known as glycogen storage disease type III (GSD III), is caused by a deficiency of the debranching enzyme, amylo-1,6-glucosidase. This enzyme plays a crucial role in breaking down glycogen, a complex sugar stored in the body's cells for energy. A deficiency prevents the proper breakdown of glycogen, leading to its abnormal buildup in the liver and muscles. This accumulation of abnormal glycogen impairs the function of these organs and tissues.
Understanding the Mechanism
- Enzyme Deficiency: The root cause is a genetic mutation in the AGL gene, responsible for producing the debranching enzyme. This genetic defect results in an insufficient amount or a completely non-functional enzyme.
- Glycogen Accumulation: The lack of a properly functioning debranching enzyme prevents the complete breakdown of glycogen. This leads to an accumulation of abnormal, structurally altered glycogen within cells.
- Organ Dysfunction: This abnormal glycogen buildup disrupts the normal functioning of the liver and muscles, leading to the characteristic symptoms of Cori's disease.
Symptoms and Manifestations
The symptoms of Cori's disease vary in severity and can manifest differently in individuals. Common symptoms include:
- Enlarged Liver (Hepatomegaly): The liver swells due to glycogen accumulation.
- Growth Delay: Children with Cori's disease may experience impaired growth during childhood.
- Low Blood Sugar (Hypoglycemia): The inability to properly break down glycogen can result in low blood sugar levels.
- Muscle Weakness (Myopathy): Muscle weakness can occur due to glycogen buildup in muscle tissue.
- Elevated Fat Levels: Abnormal fat levels in the blood may also be present.
Inheritance
Cori's disease is inherited in an autosomal recessive pattern. This means that both parents must carry a copy of the mutated AGL gene for their child to inherit the condition.
