Factor IXPortland: a nonsense mutation (CGA to TGA) resulting in hemophilia B

Am J Hum Genet. 1989 Apr;44(4):567-9.


Male siblings with severe hemophilia b were studied for the molecular defect responsible for their disorder. To define the precise DNA alteration, a 362-bp fragment in the first part of exon VIII of the factor IX gene was amplified and sequenced. A single-base-pair substitution of C----T at the nucleotide sequence 30875 was found which resulted in a nonsense mutation (TGA) and terminated the protein synthesis of factor IX at amino acid residue 252. The single-base change occurred as a classic CG dinucleotide alteration to TG (or CA), a common mechanism for point mutations in mammals.

Publication types

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

MeSH terms

  • Base Sequence
  • Factor IX / genetics*
  • Gene Amplification
  • Hemophilia B / genetics*
  • Humans
  • Mutation
  • Pedigree
  • Protein Biosynthesis
  • X Chromosome


  • Factor IX