Errors of metabolism

Overview of errors of metabolism

Classification
External resources

Errors of metabolism, also known as inborn errors of metabolism, are a group of rare genetic disorders that affect the body's ability to convert food into energy. These disorders are typically caused by defects in specific enzymes that are necessary for the metabolism of proteins, carbohydrates, or fats. The term "inborn errors of metabolism" was first coined by the British physician Archibald Garrod in the early 20th century.

Overview

Errors of metabolism are usually inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the defective gene, one from each parent, to manifest the disorder. These conditions can lead to an accumulation of toxic substances or a deficiency of critical compounds, resulting in a wide range of symptoms and potential complications.

Classification

Errors of metabolism can be classified based on the type of metabolic pathway affected:

Amino Acid Metabolism Disorders

These disorders affect the metabolism of amino acids, the building blocks of proteins. Examples include:

• Phenylketonuria (PKU)
• Maple syrup urine disease (MSUD)
• Homocystinuria

Carbohydrate Metabolism Disorders

These disorders involve the metabolism of carbohydrates, which are essential sources of energy. Examples include:

• Galactosemia
• Glycogen storage disease
• Fructose intolerance

Lipid Metabolism Disorders

These disorders affect the metabolism of lipids, which are fats and fat-like substances. Examples include:

• Gaucher's disease
• Niemann-Pick disease
• Tay-Sachs disease

Organic Acid Metabolism Disorders

These disorders involve the metabolism of organic acids. Examples include:

• Methylmalonic acidemia
• Propionic acidemia

Diagnosis

Diagnosis of errors of metabolism often involves a combination of clinical evaluation, biochemical tests, and genetic testing. Newborn screening programs are crucial for early detection of many of these disorders, allowing for prompt intervention and management.

Treatment

Treatment strategies for errors of metabolism vary depending on the specific disorder and may include:

• Dietary modifications to avoid certain substrates
• Supplementation with vitamins or cofactors
• Enzyme replacement therapy
• Gene therapy (in experimental stages for some disorders)

Prognosis

The prognosis for individuals with errors of metabolism depends on the specific disorder, the severity of the condition, and the timeliness of diagnosis and treatment. Early intervention can significantly improve outcomes for many of these disorders.

Also see

• Metabolic disorder
• Genetic disorder
• Newborn screening
• Enzyme replacement therapy