Succinyl-CoA acetoacetate transferase deficiency

Succinyl-CoA:3-ketoacid coenzyme A transferase (SCOT) deficiency is a rare metabolic disorder characterized by an inability to convert ketone bodies into acetyl-CoA, a crucial step in ketolysis. This condition is also known as succinyl-CoA acetoacetate transferase deficiency. It is an autosomal recessive disorder, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected.

Symptoms and Diagnosis

The primary symptoms of SCOT deficiency include episodes of ketoacidosis, which can be triggered by periods of fasting or illness. Symptoms of ketoacidosis may include nausea, vomiting, dehydration, and rapid breathing. In severe cases, it can lead to coma and even death if not treated promptly. Diagnosis typically involves biochemical tests that show elevated levels of ketone bodies in the blood and urine, along with genetic testing to identify mutations in the OXCT1 gene, which encodes the enzyme succinyl-CoA:3-ketoacid coenzyme A transferase.

Pathophysiology

The biochemical pathway affected in SCOT deficiency is ketolysis, which is the process by which ketone bodies are broken down to produce acetyl-CoA, an essential molecule for energy production in the mitochondria. In SCOT deficiency, the enzyme required for the conversion of acetoacetate, one of the primary ketone bodies, into acetyl-CoA is deficient or non-functional. This leads to an accumulation of ketone bodies, which are acidic, causing the blood pH to drop and resulting in ketoacidosis.

Treatment

Treatment for SCOT deficiency focuses on preventing episodes of ketoacidosis by avoiding fasting and managing illnesses promptly. A high-carbohydrate, low-fat diet may be recommended to minimize the production of ketone bodies. During acute episodes of ketoacidosis, intravenous glucose and bicarbonate may be administered to correct the metabolic imbalance.

Genetics

SCOT deficiency is caused by mutations in the OXCT1 gene, which is located on chromosome 5. This gene encodes the enzyme succinyl-CoA:3-ketoacid coenzyme A transferase, which is essential for the ketolysis pathway. The disorder is inherited in an autosomal recessive pattern, which means that an individual must inherit two copies of the mutated gene, one from each parent, to be affected.

Epidemiology

SCOT deficiency is an extremely rare disorder, with only a few cases reported in the medical literature. Due to its rarity, the exact prevalence is unknown.

See Also

• Metabolic disorder
• Ketoacidosis
• Autosomal recessive inheritance
• Mitochondria

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