Inborn errors of amino acid metabolism

Inborn errors of amino acid metabolism are a group of rare genetic disorders that disrupt the normal metabolism of amino acids. These disorders are typically present from birth and can lead to a variety of health problems, including developmental delays, neurological disorders, and physical abnormalities.

Overview

Amino acids are the building blocks of proteins and play a crucial role in many bodily functions. The body typically metabolizes amino acids through a series of chemical reactions. However, in individuals with inborn errors of amino acid metabolism, one or more of these reactions are disrupted due to genetic mutations. This can lead to an accumulation of certain amino acids or their metabolites in the body, or a deficiency of others, both of which can have harmful effects.

Types of Disorders

There are many different types of inborn errors of amino acid metabolism, each associated with a specific metabolic pathway. Some of the most common include:

• Phenylketonuria (PKU): This disorder is caused by a deficiency in the enzyme phenylalanine hydroxylase, which is needed to metabolize the amino acid phenylalanine. Without this enzyme, phenylalanine builds up in the body and can cause brain damage and intellectual disability.

• Maple syrup urine disease (MSUD): This disorder is caused by a deficiency in the enzyme complex branched-chain alpha-keto acid dehydrogenase, which is needed to metabolize the branched-chain amino acids leucine, isoleucine, and valine. Without this enzyme complex, these amino acids and their metabolites build up in the body and can cause neurological damage and death if not treated.

• Tyrosinemia: This disorder is caused by a deficiency in one of the enzymes needed to metabolize the amino acid tyrosine. Without these enzymes, tyrosine and its metabolites build up in the body and can cause liver and kidney damage, neurological problems, and skin and eye abnormalities.

Diagnosis and Treatment

Diagnosis of inborn errors of amino acid metabolism typically involves biochemical tests to measure the levels of amino acids and their metabolites in the body, as well as genetic testing to identify the specific mutation causing the disorder.

Treatment typically involves dietary management to limit the intake of the problematic amino acid and/or supplementation with the deficient amino acid or its metabolites. In some cases, enzyme replacement therapy or other medical treatments may be used.

See Also

• Metabolic disorder
• Genetic disorder
• Amino acid metabolism