title: Cystatin C in cerebrospinal fluid and multiple sclerosis.
abstract: OBJECTIVE
  A recent study using surface-enhanced laser desorption/ionization time-of-flight analysis of cerebrospinal fluid identified a 12.5 kDa truncated isoform of cystatin C (CysC) as a specific biomarker for multiple sclerosis (MS).
  
  
  METHODS
  Surface-enhanced laser desorption/ionization time-of-flight analysis of cerebrospinal fluid samples from 43 MS patients and 46 healthy control subjects.
  
  
  RESULTS
  Full-length CysC (13.4 kDa) concentration was similar in MS and control samples. The 12.5 kDa CysC protein was produced from full-length CysC by N-terminal cleavage during storage at -20 degrees C.
  
  
  CONCLUSIONS
  The 12.5 kDa CysC isoform is a storage-related artifact and is not useful as a diagnostic marker for MS.
authors.affiliation: Department of Clinical Neuroscience, University of Göteborg, Sahlgrenska University Hospital/Mölndal, Mölndal, Sweden.
authors.forename: Sara F
authors.initials: SF
authors.lastname: Hansson
authors.forename: Anja Hviid
authors.initials: AH
authors.lastname: Simonsen
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.forename: Oluf
authors.initials: O
authors.lastname: Andersen
authors.forename: Sara
authors.initials: S
authors.lastname: Haghighi
authors.forename: Inger
authors.initials: I
authors.lastname: Fagerberg
authors.forename: Ulf
authors.initials: U
authors.lastname: Andréasson
authors.forename: Ann
authors.initials: A
authors.lastname: Westman-Brinkmalm
authors.forename: Anders
authors.initials: A
authors.lastname: Wallin
authors.forename: Ulla
authors.initials: U
authors.lastname: Rüetschi
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
mesh_terms: D000595:Amino Acid Sequence; D016477:Artifacts; D015415:Biomarkers / Q000134:cerebrospinal fluid; D055316:Cystatin C; D015891:Cystatins / Q000134:cerebrospinal fluid* / Q000737:chemistry / Q000235:genetics; D004356:Drug Storage; D005615:Freezing; D006801:Humans; D008970:Molecular Weight; D009103:Multiple Sclerosis / Q000134:cerebrospinal fluid*; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000134:cerebrospinal fluid / Q000737:chemistry / Q000235:genetics; D020033:Protein Isoforms / Q000134:cerebrospinal fluid / Q000737:chemistry / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D010446:Peptide Fragments; D020033:Protein Isoforms