Enzyme activity in classical and variant forms of maple syrup urine disease

Joseph Dancis, Joel Hutzler, Selma E. Snyderman, Rody P. Cox

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


The branched-chain keto acid decarboxylase activity has been determined in skinfibroblasts grown from six subjects with classical maple syrup urine disease and six with variant forms of the disease. The level of activity in the skin fibroblasts reflects the ability of the individual to degrade the amino acids, thus providing an index of the severity of the disease. Observations on sibling pairs indicate that the level of enzyme activity and the severity of the disease are genetically determined. A 3 grade classification is proposed based on tolerance for dietary protein. The metabolic defect in all instances involved the three branched-chain amino acids, providing further support for the concept that this degradative step is under the control of a single gene.

Original languageEnglish (US)
Pages (from-to)312-320
Number of pages9
JournalThe Journal of pediatrics
Issue number2
StatePublished - Aug 1972

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


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