Fatty acid oxidation disorder

Fatty Acid Oxidation Disorder
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Hypoglycemia, lethargy, muscle weakness, cardiomyopathy
Complications	N/A
Onset	Infancy or childhood
Duration	N/A
Types	N/A
Causes	Genetic mutation
Risks	N/A
Diagnosis	Blood test, urine test, genetic testing
Differential diagnosis	N/A
Prevention	N/A
Treatment	Dietary management, carnitine supplementation
Medication	N/A
Prognosis	Variable
Frequency	N/A
Deaths	N/A

Fatty Acid Oxidation Disorder (FAOD) refers to a group of genetic disorders that affect the body's ability to break down fatty acids into energy. These disorders are caused by defects in the enzymes involved in the beta-oxidation pathway, which is crucial for energy production, especially during periods of fasting or increased energy demand.

Pathophysiology

Fatty acid oxidation is a metabolic process that occurs in the mitochondria of cells. It involves the breakdown of long-chain fatty acids into acetyl-CoA, which then enters the citric acid cycle to produce adenosine triphosphate (ATP), the energy currency of the cell. In individuals with FAOD, mutations in genes encoding enzymes of the beta-oxidation pathway lead to an accumulation of fatty acids and their derivatives, resulting in toxic effects and energy deficiency.

Types of Fatty Acid Oxidation Disorders

FAODs are classified based on the specific enzyme that is deficient or dysfunctional. Common types include:

• Medium-chain acyl-CoA dehydrogenase deficiency (MCADD): The most common FAOD, characterized by a deficiency in the enzyme responsible for breaking down medium-chain fatty acids.
• Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD): Involves a defect in the enzyme that metabolizes very long-chain fatty acids.
• Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD): Affects the enzyme responsible for the oxidation of long-chain 3-hydroxyacyl-CoA compounds.
• Carnitine palmitoyltransferase I deficiency (CPT I): Results from a defect in the enzyme that transports long-chain fatty acids into the mitochondria.
• Carnitine palmitoyltransferase II deficiency (CPT II): Involves a defect in the enzyme that facilitates the final step of fatty acid oxidation.

Clinical Presentation

Symptoms of FAODs can vary widely depending on the specific disorder and the severity of the enzyme deficiency. Common clinical features include:

• Hypoglycemia: Low blood sugar levels, especially during fasting or illness.
• Lethargy and fatigue: Due to insufficient energy production.
• Muscle weakness and rhabdomyolysis: Muscle breakdown can occur, leading to pain and weakness.
• Cardiomyopathy: Heart muscle dysfunction, which can be life-threatening.
• Hepatomegaly: Enlarged liver due to fat accumulation.

Diagnosis

Diagnosis of FAODs typically involves a combination of clinical evaluation, laboratory testing, and genetic analysis. Key diagnostic tests include:

• Blood test: Measurement of acylcarnitine profiles and free fatty acids.
• Urine test: Detection of organic acids and ketones.
• Genetic testing: Identification of mutations in genes associated with fatty acid oxidation.

Management

Management of FAODs focuses on preventing metabolic crises and maintaining energy balance. Strategies include:

• Dietary management: Frequent meals and snacks high in carbohydrates and low in fats to prevent hypoglycemia.
• Carnitine supplementation: To enhance the transport of fatty acids into mitochondria.
• Avoidance of fasting: Ensuring regular food intake to prevent energy depletion.
• Emergency protocols: For managing acute metabolic decompensation.

Prognosis

The prognosis for individuals with FAODs varies depending on the specific disorder and the effectiveness of management strategies. Early diagnosis and appropriate treatment can significantly improve outcomes and quality of life.

See Also

• Metabolic disorder
• Inborn error of metabolism
• Mitochondrial disease

External Links

• National Human Genome Research Institute
• National Organization for Rare Disorders