Maple syrup urine disease (MSUD) is a rare, inherited metabolic disorder that affects the body's ability to metabolize amino acids due to a deficiency in the activity of the branched-chain alpha-ketoacid dehydrogenase (BCKAD) complex.[3] It particularly affects the metabolism of amino acids—leucine, isoleucine, and valine.[4] With MSUD, the body is not able to properly break down these amino acids, therefore leading to the amino acids to build up in urine and become toxic. The condition gets its name from the distinctive sweet odor of affected infants' urine and earwax due to the buildup of these amino acids.[5]
^Blackburn PR, Gass JM, Vairo FP, Farnham KM, Atwal HK, Macklin S, et al. (2020). Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJ, Gripp KW, Mirzaa GM, Amemiya A (eds.). "Maple Syrup Urine Disease". GeneReviews [Internet]. University of Washington. PMID20301495. NBK1319.
^Lavin LR, Higby N, Abramo T (September 2015). "Newborn Screening: What Does the Emergency Physician Need to Know?". Pediatric Emergency Care. 31 (9): 661–667. doi:10.1097/PEC.0000000000000549. PMID26335232.