Direct carrier testing in 14 families with haemophilia B

Lancet. 1989 Sep 2;2(8662):526-9. doi: 10.1016/s0140-6736(89)90653-3.


Direct carrier testing was done in 54 at-risk female relatives of haemophilic patients by initially analysing 2.46 kb of the factor IX gene in 1 haemophiliac per family by genomic amplification with transcript sequencing. A presumptive mutation was found in all 14 haemophiliacs examined. Analyses were then done either by sequencing the appropriate region in at-risk female relatives or by detection of an altered restriction site. A simulation indicated that the mutation will be associated with an altered restriction site in about half the families. The technique has clinical application.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed RNA Polymerases / genetics
  • Endonucleases / metabolism
  • Evaluation Studies as Topic
  • Factor IX / genetics*
  • Female
  • Genetic Carrier Screening / methods*
  • Haplotypes
  • Hemophilia B / enzymology
  • Hemophilia B / genetics*
  • Humans
  • Male
  • Mutation*
  • Nucleic Acid Amplification Techniques*
  • Pedigree
  • Polymorphism, Restriction Fragment Length
  • Transcription, Genetic*


  • Factor IX
  • DNA-Directed RNA Polymerases
  • DNA-Directed DNA Polymerase
  • Endonucleases