A Case of Maple Syrup Urine Disease detected by Tandem Mass Spectrometry in Newborn Screening Test

ABSTRACT

Maple syrup urine disease (MSUD) is an autosomal recessive disorder. Impaired activity of the branched-chain 2-oxo acid dehydrogenase complex causes accumulation of branched-chain L-amino and 2-oxo acid that can exert neurotoxic effects. MSUD presents heterogeneous clinical and molecular phenotypes. Severity of the disease, ranging from classical to mild variant types, is commonly classified on the basis of indirect parameters, e.g. onset, leucine tolerance and/or residual enzyme activity in cell. Since early 1990's, tandem mass spectrometry has been applied to newborn screening, because it is amenable to population-wide testing for a large number of disorders of fatty acid, organic acid, and amino acid metabolism. And so, we report a case of MSUD in 15 days old boy detected by newborn screening using tandem mass spectrometry.