Factor IX Cardiff: a variant factor IX protein that shows abnormal activation is caused by an arginine to cysteine substitution at position 145

Br J Haematol. 1989 Aug;72(4):556-60. doi: 10.1111/j.1365-2141.1989.tb04323.x.


Crude barium chloride eluates prepared from 12 unrelated patients with cross-reacting material positive (CRM+) haemophilia B were activated with celite eluate, the reaction products resolved after reduction by 13% SDS-PAGE, and factor IX antigenic material detected by probing with radiolabelled immunopurified rabbit anti-factor IX antiserum followed by autoradiography. Out of the 12, one sample showed faulty activation with the production of a stable reaction product with a MW compatible with that of a putative light chain-activation intermediate. In order to confirm this, two oligonucleotide primers that bracketed exon 6 of the factor IX gene were constructed and used to prime a polymerase chain reaction on DNA isolated from the patient's peripheral blood leucocytes. A single 489 nucleotide DNA fragment was obtained, gel purified, subcloned into M13, and DNA sequencing carried out on both strands. A single C to T transition was discovered that changed the Arg residue at position 145, the first residue of the first bond in the activation peptide, to a Cys, a result that confirmed the inferences drawn from the activation studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens / analysis
  • Arginine
  • Base Sequence
  • Cloning, Molecular
  • Cysteine
  • DNA / genetics*
  • Exons
  • Factor IX / genetics*
  • Gene Expression Regulation
  • Hemophilia B / genetics*
  • Humans
  • Molecular Weight


  • Antigens
  • factor IX Cardiff
  • Factor IX
  • DNA
  • Arginine
  • Cysteine