Summary about Disease
Glucose-6-phosphatase deficiency (G6PD deficiency, also known as von Gierke disease) is a rare genetic metabolic disorder affecting the liver, kidneys, and intestines. It results from a deficiency of the enzyme glucose-6-phosphatase, which is essential for the breakdown of glycogen into glucose and for releasing glucose from the liver into the bloodstream. This deficiency leads to an accumulation of glycogen in these organs and the inability to maintain normal blood sugar levels (hypoglycemia).
Symptoms
Hypoglycemia (low blood sugar): This is the most common and significant symptom, especially in infancy. It can cause seizures, irritability, rapid breathing, sweating, and in severe cases, brain damage or death.
Hepatomegaly (enlarged liver): The liver becomes enlarged due to glycogen accumulation.
Nephromegaly (enlarged kidneys): The kidneys also become enlarged due to glycogen accumulation.
Growth retardation: Affected individuals may experience delayed growth.
Lactic acidosis: Build-up of lactic acid in the blood.
Hyperlipidemia: Elevated levels of fats (lipids) in the blood.
Gout: Some individuals may develop gout due to elevated uric acid levels.
Distended abdomen: Enlarged liver and kidneys can cause abdominal swelling.
Osteopenia/Osteoporosis: Weakening of the bones
Causes
G6PD deficiency is caused by mutations in the G6PC gene (for type Ia) or the *SLC37A4* gene (for type Ib). These genes provide instructions for making the glucose-6-phosphatase enzyme and the glucose-6-phosphate translocase protein, respectively. These mutations are inherited in an autosomal recessive pattern, meaning both parents must carry a copy of the mutated gene for a child to be affected.
Type Ia: Mutations in the G6PC gene.
Type Ib: Mutations in the SLC37A4 gene, also causing neutropenia and inflammatory bowel disease.
Medicine Used
4. Medicine used There is no cure for G6PD deficiency; treatment focuses on managing symptoms and preventing complications.
Dietary management: Frequent feedings or continuous nocturnal gastric infusions (feeding tube) with uncooked cornstarch are crucial to maintain stable blood sugar levels. A diet high in complex carbohydrates and low in simple sugars is generally recommended.
Allopurinol: May be used to manage hyperuricemia (high uric acid levels) and prevent gout.
Granulocyte-colony stimulating factor (G-CSF): Used in type Ib to manage neutropenia (low white blood cell count).
Medications to manage hyperlipidemia: Statins or other lipid-lowering agents may be used.
Is Communicable
No, Glucose-6-phosphatase deficiency is not communicable. It is a genetic disorder, meaning it is inherited and cannot be spread from person to person.
Precautions
Strict dietary adherence: Following the prescribed dietary plan is essential to prevent hypoglycemia.
Frequent blood glucose monitoring: Regular monitoring of blood sugar levels is crucial for managing the condition.
Avoidance of fasting: Prolonged periods without food should be avoided.
Prompt treatment of infections: Infections can worsen metabolic imbalances.
Genetic counseling: For families with a history of G6PD deficiency, genetic counseling can help assess the risk of having affected children.
How long does an outbreak last?
G6PD deficiency is a chronic condition. It's not an outbreak-based illness. The effects and symptoms are ongoing and require continuous management. Hypoglycemic episodes can occur if the dietary and medical management are not properly followed.
How is it diagnosed?
Newborn screening: Many states include G6PD deficiency in their newborn screening programs.
Blood tests: Measuring blood glucose, lactate, uric acid, and lipid levels can provide clues.
Enzyme assay: A blood test can measure the activity of the glucose-6-phosphatase enzyme in a liver biopsy sample. This is the definitive diagnostic test.
Genetic testing: Sequencing the G6PC or *SLC37A4* gene can identify specific mutations.
Liver biopsy: A small sample of liver tissue may be taken to assess glycogen accumulation and enzyme activity, although this is less common now with genetic testing available.
Timeline of Symptoms
9. Timeline of symptoms
Newborn/Infancy: Hypoglycemia is the most prominent symptom, often presenting within the first few months of life. Hepatomegaly may also be apparent.
Childhood: Growth retardation, continued hepatomegaly, and metabolic abnormalities become more evident.
Adulthood: Complications such as gout, kidney disease, and liver adenomas may develop over time.
Important Considerations
Early diagnosis and management are crucial to prevent severe complications such as brain damage from hypoglycemia.
Type Ib G6PD deficiency requires additional monitoring and treatment due to the presence of neutropenia and inflammatory bowel disease.
Lifelong adherence to dietary guidelines and medical management is essential for individuals with G6PD deficiency.
The severity of symptoms can vary among individuals, even with the same genetic mutation.
Regular follow-up with a metabolic specialist is necessary to monitor for complications and adjust treatment as needed.