title: A modified liquid chromatography/tandem mass spectrometry method for predominant disaccharide units of urinary glycosaminoglycans in patients with mucopolysaccharidoses.
abstract: BACKGROUND
  The identification of acid mucopolysaccharide by the liquid chromatography/tandem mass spectrometry method (LC-MS/MS) of the predominant disaccharide units of glycosaminoglycans (GAGs) (chondroitin sulfate, CS; dermatan sulfate, DS; heparan sulfate, HS) after methanolysis is validated and applicable for mucopolysaccharidosis (MPS) type determination.
  
  
  METHODS
  A total of 76 urine samples were collected and analyzed, from nine MPS I patients, 13 MPS II patients, seven MPS III patients, eight MPS VI patients, and 39 normal controls. Urinary GAG was first precipitated by the Alcian blue method followed by a treatment of 3 N HCl methanol. The protonated species of the methylated disaccharide products were detected by using a multiple reaction monitoring experiment. Internal standards, [2H6] CS, [2H6] DS and [2H6] HS, were prepared in-house by deuteriomethanolysis of CS, DS and HS.
  
  
  RESULTS
  One particular disaccharide for each GAG was selected, in which the parent ion and its daughter ion after collision were m/z 426.1 → 236.2 for DS (m/z 432 → 239 for dimers derived from [2H6] CS and [2H6] DS) and m/z 384.2 → 161.9 for HS (m/z 390.4 → 162.5 for the [2H6] HS dimer). The quantities of DS and HS were determined, which varied from one MPS type to the other. The results can be used to evaluate the severity of MPS subgroups, as well as urinary GAG amelioration at follow-up after enzyme replacement therapy (ERT).
  
  
  CONCLUSIONS
  The modified LC-MS/MS method for MPS type determination is specific, sensitive, validated, accurate, and applicable for simultaneous quantifications of urinary DS and HS. This method can help to make correct diagnosis of MPS patients and evaluate the effectiveness of ERT.
authors.forename: Chih-Kuang
authors.initials: CK
authors.lastname: Chuang
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Lin
authors.forename: Tuen-Jen
authors.initials: TJ
authors.lastname: Wang
authors.forename: Chia-Chen
authors.initials: CC
authors.lastname: Tsai
authors.forename: Hsuan-Liang
authors.initials: HL
authors.lastname: Liu
authors.affiliation: Division of Genetics and Metabolism, Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan. zsplin14@gmail.com.
authors.forename: Shuan-Pei
authors.initials: SP
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002853:Chromatography, Liquid / Q000379:methods*; D004187:Disaccharides / Q000032:analysis / Q000652:urine*; D056947:Enzyme Replacement Therapy; D006025:Glycosaminoglycans / Q000652:urine*; D006801:Humans; D009083:Mucopolysaccharidoses / Q000188:drug therapy / Q000652:urine*; D012015:Reference Standards; D053719:Tandem Mass Spectrometry / Q000379:methods*; D055815:Young Adult
chemical_list: D004187:Disaccharides; D006025:Glycosaminoglycans