title: High level of oxysterols in neonatal cholestasis: a pitfall in analysis of biochemical markers for Niemann-Pick type C disease.
abstract: BACKGROUND
  Niemann-Pick disease type C (NPC) is a rare lipid storage disorder characterized by progressive neurological deterioration. Diagnosing NPC is challenging as clinical signs and symptoms are variable and non-specific. Two oxysterols, cholestane-3β,5α,6β-triol (triol) and 7-ketocholesterol (7KC), have been proposed as biomarkers for aiding diagnosis of NPC. This study evaluated the use of triol and 7KC as biomarkers in cholestatic neonates with suspected NPC.
  
  
  METHODS
  Plasma triol and 7KC were analysed as dimethylglycine esters using an liquid chromatography - tandem mass spectrometry (LC-MS/MS) assay in selected neonates with severe cholestasis and suspected NPC (n=7), adults with cholestasis (n=15), patients with confirmed NPC (positive controls; n=11 [one child and 10 adults]), healthy subjects (negative controls; n=40 [20 children and 20 adults]), and cholestatic adults (comparative reference; n=15). The LC-MS/MS method was subjected to a number of tests for accuracy and consistency.
  
  
  RESULTS
  Triol and 7KC levels were substantially and significantly increased in NPC positive patients compared with healthy controls (p<0.001). However, positive results (markedly increased levels of both oxysterols) were identified in 6/7 (86%) neonates with cholestasis. Genetic testing confirmed NPC only in one neonate who had increased triol and 7KC, and increased oxysterol levels among neonates with no identified NPC gene mutations were considered likely due to biliary atresia (BA).
  
  
  CONCLUSIONS
  While the potential of oxysterols as NPC biomarkers has been well evaluated in older patient populations (without cholestasis), our data suggest that cholestasis might represent a pitfall in oxysterol measurements intended to aid diagnosis of NPC in affected patients.
authors.forename: Giulia
authors.initials: G
authors.lastname: Polo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Burlina
authors.forename: Francesca
authors.initials: F
authors.lastname: Furlan
authors.forename: Thilini
authors.initials: T
authors.lastname: Kolamunnage
authors.forename: Mara
authors.initials: M
authors.lastname: Cananzi
authors.forename: Laura
authors.initials: L
authors.lastname: Giordano
authors.forename: Martina
authors.initials: M
authors.lastname: Zaninotto
authors.forename: Mario
authors.identifier: http://orcid.org/0000-0002-0270-1711
authors.initials: M
authors.lastname: Plebani
authors.forename: Alberto
authors.initials: A
authors.lastname: Burlina
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D002138:Calibration; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002779:Cholestasis / Q000097:blood / Q000175:diagnosis*; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000175:diagnosis*; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D052556:Niemann-Pick Disease, Type C / Q000097:blood / Q000175:diagnosis*; D000072376:Oxysterols / Q000097:blood*; D011446:Prospective Studies; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D055815:Young Adult
chemical_list: D015415:Biomarkers; D000072376:Oxysterols