title: Discordant diagnoses obtained by different approaches in antithrombin mutation analysis.
abstract: OBJECTIVE
  In hereditary antithrombin (AT) deficiency it is important to determine the underlying mutation since the future risk of thromboembolism varies considerably between mutations. DNA investigations are in general thought of as flawless and irrevocable, but the diagnostic approach can be critical. We therefore investigated mutation results in the AT gene, SERPINC1, with two different approaches.
  
  
  METHODS
  Sixteen patients referred to the Centre for Thrombosis and Haemostasis, Odense University Hospital, with biochemical indications of AT deficiency, but with a negative denaturing high-performance liquid chromatography (DHPLC) mutation screening (routine approach until recently) were included. As an alternative mutation analysis, direct sequencing of all exons and exon-intron boundaries without pre-selection by DHPLC was performed.
  
  
  RESULTS
  Out of sixteen patients with a negative DHPLC mutation screening, discordant results were found in ten patients (62.5%) when using direct sequencing: Eight had the Basel mutation (c.218C>T), while two had the Cambridge II mutation (c.1246G>T). For seven of the ten patients this meant an altered clinical risk-assessment for future thromboses.
  
  
  CONCLUSIONS
  Awareness must be drawn to the possibility of differences in DNA diagnostics in general and advances when using newer techniques in particular. One should consider re-analysis of results obtained by earlier sequencing strategies, as clinically important information can be overlooked.
authors: Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Denmark.
authors: Søren
authors: S
authors: Feddersen
authors: Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Denmark. Electronic address: mads.nybo@rsyd.dk.
authors: Mads
authors: M
authors: Nybo
mesh_terms: D000328:Adult; D000990:Antithrombin III / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods; D005091:Exons / Q000235:genetics; D005260:Female; D006402:Hematologic Diseases / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*
chemical_list: C542513:SERPINC1 protein, human; D000990:Antithrombin III
keywords: Antithrombin; Mutation analysis; Risk assessment