Which amino acid is typically elevated in a patient with maple syrup urine disease?

In a patient with maple syrup urine disease (MSUD), the amino acid that is typically elevated is leucine. This condition is a metabolic disorder caused by a deficiency in the branched-chain alpha-keto acid dehydrogenase complex, which is essential for the proper metabolism of branched-chain amino acids, including leucine, isoleucine, and valine. When this enzyme is deficient, these amino acids accumulate in the blood due to their inability to be properly metabolized, leading to toxicity and associated symptoms.

Leucine, in particular, is the most significantly elevated amino acid in this disorder. Elevated levels of leucine can lead to neurological symptoms and characteristic features in the urine, which typically has a sweet, maple syrup-like odor. This condition requires prompt dietary intervention to manage and reduce the levels of these amino acids and prevent serious complications. Understanding the metabolic pathways and the role of specific amino acids in disorders like MSUD is crucial for diagnosis and treatment.