In Maple syrup urine disease, the amino acids excreted in urine are all EXCEPT:
- Maple syrup urine disease is a defect in the catabolism of branched chain amino acids i.e. Valine, Leucine and Isoleucine. As a result these amino acids are excreted in urine. - This defect occurs due to the inherited deficiency of branched Chain Keto-acid Decarboxylase. - So the answer is Phenylalanine Extra information: MAPLE Syrup urine disease: Autosomal Recesive Clinical Features 1. Burnt sugar like odour (because of isoleucine) 2. Ketosis, vomiting, feeding problems 3. Mental retardation (because of increased leucine) There are 4 known types of Maple Syrup Urine Disease: Type IA and IB MSUD arise from mutations in the E1a and E1b gene, which encode the enzyme a-Ketoacid decarboxylase. Type II arises from mutations in the E2 gene, which encodes Dihydrolipoyltransacylase. Type III arises from mutations in the E3 gene, which encodes Dihydrolipoamide dehydrogenase.
Leucine
Phenylalanine
Isoleucine
Valine
Classification and metabolism of amino acids