title: Application of liquid chromatography-tandem mass spectrometry in the diagnosis and follow-up of maple syrup urine disease in a Chinese population.
abstract: BACKGROUND
  Maple syrup urine disease (MSUD) is an inherited disorder caused by a deficiency of the mitochondrial branched-chain keto acid dehydrogenase complex. We investigated whether liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a more reliable and accurate method than MS/MS in the diagnosis and management of patients with MSUD in a Chinese population.
  
  
  METHODS
  A total of 370 dried blood spots (DBS) from healthy neonates, 44 DBS specimens from phenylketonuria neonates, and 38 DBS samples from 10 MSUD patients were retrospectively tested using the LC-MS/MS method. The results were compared with those obtained by the MS/MS method.
  
  
  RESULTS
  The reference intervals of branched-chain amino acids (BCAAs) and alloiosleucine (Allo-Ile) were estimated for both sexes. In classic MSUD patients, Allo-Ile was markedly elevated (average of 136 μmol/L, which was significantly higher than the normal value, <5 μmol/L). The averages of BCAAs were also markedly elevated continually during the treatment.
  
  
  CONCLUSIONS
  The application of the LC-MS/MS method in the measurement of Allo-Ile and BCAAs in DBS is more useful for diagnosing and managing classic MSUD than the MS/MS method.
authors: Shanghai Institute for Pediatric Research, Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Jiatong University School of Medicine, Shanghai, China.
authors: Na
authors: N
authors: Lin
authors: Jun
authors: J
authors: Ye
authors: Wenjuan
authors: W
authors: Qiu
authors: Lianshu
authors: L
authors: Han
authors: Huiwen
authors: H
authors: Zhang
authors: Xuefan
authors: X
authors: Gu
mesh_terms: D000597:Amino Acids, Branched-Chain / Q000097:blood*; D044466:Asian People; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D059788:Dried Blood Spot Testing / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008375:Maple Syrup Urine Disease / Q000175:diagnosis* / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards; D010661:Phenylketonurias / Q000175:diagnosis / Q000378:metabolism; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D000597:Amino Acids, Branched-Chain