Inborn error of metabolism

Inborn Errors of Metabolism (IEM) are a group of disorders that cause a block in a metabolic pathway leading to clinically significant consequences. These are due to defects in single genes that code for enzymes that facilitate conversion of various substances (substrates) into others (products). In most of the disorders, problems arise due to accumulation of substances which are toxic or interfere with normal function, or to the effects of reduced ability to synthesize essential compounds.

Definition

An Inborn error of metabolism is a rare genetic disorder resulting in a deficiency of one or more specific metabolic pathways due to defects in enzymes. This deficiency leads to a block in the metabolic pathway involved.

Classification

Inborn errors of metabolism are classified according to the affected enzyme and the metabolic pathway involved. They can be broadly divided into:

• Disorders of carbohydrate metabolism
• Disorders of amino acid metabolism
• Disorders of organic acid metabolism
• Disorders of fatty acid oxidation and mitochondrial metabolism
• Disorders of porphyrin metabolism
• Disorders of purine or pyrimidine metabolism
• Disorders of steroid metabolism
• Disorders of mitochondrial function
• Disorders of peroxisomal function

Symptoms

The symptoms of inborn errors of metabolism vary widely and are often nonspecific, making these disorders challenging to diagnose. Symptoms can range from mild to severe and can involve any organ system of the body.

Diagnosis

Diagnosis of inborn errors of metabolism is often done by newborn screening with tandem mass spectrometry. This can detect many inborn errors of metabolism, allowing for early treatment.

Treatment

Treatment for inborn errors of metabolism varies depending on the specific disorder, but often involves dietary management to limit the intake of a particular metabolite or to supplement a deficient product.

See Also

• Metabolism
• Genetic disorder
• Enzyme
• Newborn screening

Inborn error of metabolism Resources
Latest articles Most recent articles Ongoing trials	Wikipedia