Maple syrup urine disease: Mechanisms and management

Patrick R. Blackburn, Jennifer M. Gass, Filippo Pinto e Vairo, Kristen M. Farnham, Herjot K. Atwal, Sarah Macklin, Eric W. Klee, Paldeep S. Atwal

Research output: Contribution to journalReview articlepeer-review

56 Scopus citations


Maple syrup urine disease (MSUD) is an inborn error of metabolism caused by defects in the branched-chain α-ketoacid dehydrogenase complex, which results in elevations of the branched-chain amino acids (BCAAs) in plasma, α-ketoacids in urine, and production of the pathognomonic disease marker, alloisoleucine. The disorder varies in severity and the clinical spectrum is quite broad with five recognized clinical variants that have no known association with genotype. The classic presentation occurs in the neonatal period with developmental delay, failure to thrive, feeding difficulties, and maple syrup odor in the cerumen and urine, and can lead to irreversible neurological complications, including stereotypical movements, metabolic decompensation, and death if left untreated. Treatment consists of dietary restriction of BCAAs and close metabolic monitoring. Clinical outcomes are generally good in patients where treatment is initiated early. Newborn screening for MSUD is now commonplace in the United States and is included on the Recommended Uniform Screening Panel (RUSP). We review this disorder including its presentation, screening and clinical diagnosis, treatment, and other relevant aspects pertaining to the care of patients.

Original languageEnglish (US)
Pages (from-to)57-66
Number of pages10
JournalApplication of Clinical Genetics
StatePublished - Sep 6 2017


  • Alloisoleucine
  • Branched-chain amino acids
  • DBT
  • Maple syrup urine disease
  • Newborn screening

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


Dive into the research topics of 'Maple syrup urine disease: Mechanisms and management'. Together they form a unique fingerprint.

Cite this