From the Guidelines
Cori disease, also known as Glycogen Storage Disease Type III (GSD III), is a rare genetic disorder that affects glycogen metabolism in the body, caused by a deficiency of the glycogen debranching enzyme, and is characterized by the accumulation of abnormal glycogen in various tissues, primarily the liver, muscles, and heart. This enzyme deficiency leads to the accumulation of abnormal glycogen in various tissues, primarily the liver, muscles, and heart, as described in the study by 1. Patients typically present with symptoms like hepatomegaly (enlarged liver), hypoglycemia (low blood sugar), growth retardation, and muscle weakness. Management focuses on maintaining normal blood glucose levels through:
- Frequent high-carbohydrate meals
- Cornstarch therapy (1-2 g/kg every 4-6 hours)
- A high-protein diet (2-3 g/kg/day), as recommended in the guidelines by 1. Some patients may require continuous overnight feeding. Regular monitoring of blood glucose, liver function, and cardiac status is essential, as outlined in the study by 1. Unlike some other glycogen storage diseases, GSD III doesn't typically respond to glucose or galactose restriction. The disease is inherited in an autosomal recessive pattern, meaning both parents must carry the defective gene for a child to be affected, as noted in the guidelines by 1. Early diagnosis and proper dietary management can significantly improve quality of life and prevent complications like liver cirrhosis and cardiomyopathy, as emphasized in the study by 1. It is essential for primary care providers and other specialists to recognize the condition and provide appropriate care for these patients, as stated in the guidelines by 1.
From the Research
Definition and Causes of Cori Disease
- Cori disease, also known as Glycogen Storage Disease Type III (GSDIII), is a rare genetic disorder caused by a deficiency of the glycogen debranching enzyme, encoded by the AGL gene 2, 3, 4, 5.
- This deficiency leads to the storage of an abnormal glycogen in the liver and in skeletal and heart muscle, resulting in various clinical manifestations.
Clinical Manifestations
- GSDIII is usually characterized by hepatic symptoms, growth failure, and myopathy 2.
- Patients with GSDIIIa show involvement of liver and cardiac/skeletal muscle, whereas GSDIIIb patients display only liver symptoms and signs 4.
- Chronic complications may involve the liver (hepatic cirrhosis, adenoma(s), and/or hepatocellular carcinoma), heart (cardiac involvement and cardiomyopathy), and muscle (pain) 4.
Diagnosis and Management
- Diagnosis of GSDIII is based on genetic testing, and management involves dietary interventions, such as frequent meals, uncooked cornstarch, and continuous gastric drip feeding 4, 5.
- A modified Atkins diet (MAD) has been suggested to have favorable outcomes in GSD IIIa, with improvements in serum glucose, transaminases, and creatine kinase levels 5.
Electrodiagnostic Characteristics
- The neuromuscular manifestations of GSDIII include myopathy and neuropathy, and are more likely to occur with increasing age, even in those diagnosed with GSDIIIb 6.
- Electrodiagnostic findings, such as nerve conduction studies and electromyography, may show abnormalities in median motor response and myopathic findings 6.