Cori disease

Cori Disease Cori disease, also known as Glycogen Storage Disease Type III (GSD III), is a rare genetic disorder that affects the body's ability to break down glycogen, a stored form of glucose. This condition is caused by a deficiency in the enzyme glycogen debranching enzyme, which is crucial for glycogenolysis, the process of converting glycogen into glucose.

Pathophysiology

Glycogen is a polysaccharide that serves as a form of energy storage in humans. In Cori disease, the deficiency of the glycogen debranching enzyme leads to the accumulation of abnormally structured glycogen in the liver and muscles. This results in hepatomegaly, hypoglycemia, and muscle weakness.

Glycogen Debranching Enzyme

The glycogen debranching enzyme has two main activities: 4-alpha-glucanotransferase and amylo-1,6-glucosidase. These activities are essential for the complete breakdown of glycogen. In Cori disease, mutations in the AGL gene, which encodes this enzyme, lead to its deficiency.

Clinical Features

Patients with Cori disease typically present with:

• Hepatomegaly: Enlarged liver due to glycogen accumulation.
• Hypoglycemia: Low blood sugar levels, especially during fasting.
• Muscle Weakness: Due to glycogen accumulation in muscle tissues.
• Growth Retardation: Delayed growth and development in children.

Diagnosis

Diagnosis of Cori disease involves:

• Biochemical Tests: Measuring enzyme activity in liver or muscle tissue.
• Genetic Testing: Identifying mutations in the AGL gene.
• Liver Biopsy: Histological examination showing glycogen accumulation.

Treatment

There is no cure for Cori disease, but management focuses on:

• Dietary Management: Frequent meals high in carbohydrates to prevent hypoglycemia.
• Cornstarch Therapy: Uncooked cornstarch can provide a slow-release form of glucose.
• Liver Transplantation: In severe cases with liver dysfunction.

Prognosis

The prognosis for individuals with Cori disease varies. With proper management, many patients can lead relatively normal lives, although they may experience complications such as liver cirrhosis or cardiomyopathy.

Research and Future Directions

Research is ongoing to better understand the molecular mechanisms of Cori disease and to develop potential gene therapies. Advances in genetic engineering and enzyme replacement therapies hold promise for future treatments.

See Also

• Glycogen Storage Disease
• Hepatomegaly
• Hypoglycemia
• Chen, Y.T., and Burchell, A. (2001). Glycogen storage diseases. In: The Metabolic and Molecular Bases of Inherited Disease, 8th ed.
• Wolfsdorf, J.I., and Weinstein, D.A. (2003). Glycogen storage diseases. Rev Endocr Metab Disord.

NIH genetic and rare disease info

• NIH info on Cori disease

Cori disease is a rare disease.