The following amino acids are excreted in urine in maple syrup disease, EXCEPT:
The biochemical defect in maple syrup urine disease (MSUD) involves the alpha-keto acid decarboxylase complex. Plasma and urinary levels of leucine, isoleucine, valine, and their -keto acids and -hydroxy acids (reduced alpha-keto acids) are elevated, but the urinary ketoacids derive principally from leucine. Signs and symptoms of MSUD include often fatal ketoacidosis, neurological derangements, mental retardation, and a maple syrup odor of urine. Ref: Rodwell V.W. (2011). Chapter 29. Catabolism of the Carbon Skeletons of Amino Acids. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.
Valine
Leucine
Isoleucine
Phenylalanine