Glycogenosis, type 0

A rare genetic disorder affecting glycogen metabolism

Glycogenosis, type 0
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Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Hypoglycemia, fatigue, muscle cramps
Complications	N/A
Onset	Infancy or early childhood
Duration	N/A
Types	N/A
Causes	Genetic mutation in the GYS2 gene
Risks	N/A
Diagnosis	Genetic testing, blood tests
Differential diagnosis	N/A
Prevention	N/A
Treatment	Dietary management, frequent meals
Medication	N/A
Prognosis	Variable, generally manageable with treatment
Frequency	N/A
Deaths	N/A

Glycogenosis, type 0, also known as Glycogen Storage Disease Type 0 (GSD 0), is a rare genetic disorder that affects the body's ability to store and utilize glycogen, a form of stored glucose. Unlike other types of glycogen storage diseases, type 0 is characterized by a deficiency in the enzyme glycogen synthase, which is responsible for converting glucose to glycogen in the liver.

Pathophysiology

Glycogenosis, type 0 is caused by mutations in the GYS2 gene, which encodes the liver isoform of glycogen synthase. This enzyme is crucial for the synthesis of glycogen from glucose. In individuals with GSD 0, the lack of functional glycogen synthase leads to an inability to store glycogen in the liver. As a result, affected individuals experience fasting hypoglycemia because they cannot mobilize glycogen stores to maintain blood glucose levels during periods of fasting.

Clinical Presentation

Symptoms of Glycogenosis, type 0 typically appear in infancy or early childhood. Common symptoms include:

• Hypoglycemia (low blood sugar), especially after fasting
• Fatigue and lethargy
• Muscle cramps
• Ketosis
• Growth retardation

Diagnosis

Diagnosis of Glycogenosis, type 0 is based on clinical symptoms, laboratory findings, and genetic testing. Blood tests may reveal hypoglycemia and ketosis. Genetic testing can confirm mutations in the GYS2 gene.

Management

Management of Glycogenosis, type 0 primarily involves dietary modifications to prevent hypoglycemia. Patients are advised to consume frequent meals rich in carbohydrates and may require cornstarch supplements to maintain blood glucose levels during fasting periods. In some cases, a high-protein diet may be recommended to provide an alternative energy source.

Prognosis

The prognosis for individuals with Glycogenosis, type 0 varies. With appropriate dietary management, many individuals can lead relatively normal lives. However, careful monitoring and management are essential to prevent complications associated with hypoglycemia.

Also see

• Glycogen storage disease
• Hypoglycemia
• Genetic disorders
• Metabolic disorders