title: Streamlined determination of lysophosphatidylcholines in dried blood spots for newborn screening of X-linked adrenoleukodystrophy.
abstract: BACKGROUND
  Pre-symptomatic hematopoietic stem cell transplantation is essential to achieve best possible outcomes for patients with the childhood cerebral form of X-linked adrenoleukodystrophy (X-ALD). We describe a high-throughput method for measurement of C20-C26 lysophosphatidylcholines (LPCs) and biochemical diagnosis of X-ALD using the same dried blood spots (DBS) routinely used for newborn screening.
  
  
  METHODS
  LPCs are extracted from 3-mm DBS punch with methanol containing an isotopically labeled LPC as internal standard. This extract is transferred to a 96-well plate, evaporated and then reconstituted in mobile phase for flow injection analysis tandem mass spectrometry (FIA-MS/MS) in selected reaction monitoring mode for measurement of four different LPCs (C20, C22, C24, C26) and the internal standard (d4-C26-LPC). Analysis time is 1.5min per sample.
  
  
  RESULTS
  The mean CVs from the intra- and inter-assay experiments for LPCs were 6.3-15.1% for C20-LPC, 4.4-18.6% for C22-LPC and 4.5-14.3% for C24-LPC. Limits of detection were determined for C20-LPC (LOD=0.03μg/mL), C22-LPC (0.03μg/mL), C24-LPC (0.03μg/mL) and C26-LPC (0.01μg/mL). Reference ranges were established from DBS of 130 newborns and 20 adults. Samples of patients with X-ALD (n=16), peroxisomal biogenesis disorders (n=8), and X-ALD carriers (n=12) were analyzed blindly and all were correctly identified.
  
  
  CONCLUSIONS
  Analysis of LPC species by FIA-MS/MS is a fast, simple and reliable method to screen for X-ALD and other peroxisomal disorders in DBS. To maximize specificity, abnormal results can be verified by a 2nd tier assay using LC-MS/MS.
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Coleman T
authors.initials: CT
authors.lastname: Turgeon
authors.affiliation: Kennedy Krieger Institute, Baltimore, MD 21205, USA.
authors.forename: Ann B
authors.initials: AB
authors.lastname: Moser
authors.affiliation: Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Mørkrid
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Magera
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Dimitar K
authors.initials: DK
authors.lastname: Gavrilov
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Devin
authors.initials: D
authors.lastname: Oglesbee
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Kimiyo
authors.initials: K
authors.lastname: Raymond
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Piero
authors.initials: P
authors.lastname: Rinaldo
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Matern
authors.affiliation: Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. Electronic address: tortorelli.silvia@mayo.edu.
authors.forename: Silvia
authors.initials: S
authors.lastname: Tortorelli
mesh_terms: D000326:Adrenoleukodystrophy / Q000097:blood*; D000328:Adult; D002853:Chromatography, Liquid; D059788:Dried Blood Spot Testing; D057166:High-Throughput Screening Assays; D006801:Humans; D007231:Infant, Newborn; D057230:Limit of Detection; D008244:Lysophosphatidylcholines / Q000097:blood*; D015997:Neonatal Screening / Q000379:methods*; D018901:Peroxisomal Disorders / Q000097:blood; D012016:Reference Values; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D008244:Lysophosphatidylcholines
keywords: Dried blood spot; Lysophosphatidylcholine; Newborn screening; Peroxisomes; Tandem mass spectrometry; X-linked adrenoleukodystrophy