PEPCK deficiency, mitochondrial

PEPCK Deficiency, Mitochondrial is a rare metabolic disorder characterized by a deficiency in the enzyme phosphoenolpyruvate carboxykinase (PEPCK). This enzyme plays a crucial role in gluconeogenesis, the process by which glucose is synthesized from non-carbohydrate sources. The mitochondrial form of PEPCK deficiency affects the enzyme located in the mitochondria, one of two forms of PEPCK found in humans. The disorder leads to various metabolic complications, including hypoglycemia, lactic acidosis, and failure to thrive.

Symptoms and Signs

Patients with mitochondrial PEPCK deficiency typically present with a range of symptoms that may include:

• Hypoglycemia (low blood sugar)
• Lactic acidosis (buildup of lactic acid in the body)
• Failure to thrive in infants
• Hepatomegaly (enlarged liver)
• Muscle weakness
• Developmental delay

Causes

Mitochondrial PEPCK deficiency is caused by mutations in the PEPCK-M gene, which encodes the mitochondrial form of the enzyme phosphoenolpyruvate carboxykinase. These genetic mutations lead to reduced activity or complete absence of the enzyme, disrupting normal gluconeogenesis and energy metabolism.

Diagnosis

Diagnosis of mitochondrial PEPCK deficiency involves a combination of clinical evaluation, laboratory testing, and genetic testing. Laboratory tests may show hypoglycemia, lactic acidosis, and elevated levels of certain amino acids in the blood. Genetic testing can confirm mutations in the PEPCK-M gene.

Treatment

There is no cure for mitochondrial PEPCK deficiency, and treatment focuses on managing symptoms and preventing metabolic crises. Treatment strategies may include:

• Dietary management to maintain normal blood glucose levels
• Supplements or medications to manage lactic acidosis
• Close monitoring of liver function and growth in children

Prognosis

The prognosis for individuals with mitochondrial PEPCK deficiency varies depending on the severity of the enzyme deficiency and the effectiveness of management strategies. Early diagnosis and intervention can improve outcomes.

See Also

• Gluconeogenesis
• Metabolic disorder
• Hypoglycemia
• Lactic acidosis

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