Which disorder is identified by a deficiency of Branched-chain alpha-keto acid dehydrogenase?

Maple syrup urine disease (MSUD) is characterized by a deficiency in the enzyme branched-chain alpha-keto acid dehydrogenase. This enzyme is crucial for the metabolism of branched-chain amino acids, specifically leucine, isoleucine, and valine. When there is a deficiency, these amino acids and their corresponding keto acids accumulate in the body, leading to a variety of symptoms.

The name of the disorder itself is derived from the characteristic sweet-smelling urine, which has been compared to maple syrup due to the presence of the ketone bodies that are not properly metabolized. Patients with MSUD may exhibit symptoms such as poor feeding, vomiting, lethargy, and seizures shortly after birth, which are indicative of a metabolic crisis if left untreated.

In the context of the other disorders mentioned, phenylketonuria involves a defect in the metabolism of phenylalanine, alkaptonuria is linked to a defect in the metabolism of tyrosine, and cystic fibrosis primarily affects the respiratory and digestive systems through dysfunction of the CFTR gene. None of these disorders is associated with the deficiency of branched-chain alpha-keto acid dehydrogenase, making maple syrup urine disease the correct identification for this