Haemophilia B caused by a missense mutation in the prepeptide sequence of factor IX

Hum Mutat. 1993;2(2):103-7. doi: 10.1002/humu.1380020207.


In the course of analysing mutation in the factor IX gene from 200 haemophilia B patients in Sweden and the UK, we have identified one patient with a prepeptide missense mutation. He has severe, antigen negative haemophilia, and complete analysis of his coding sequence reveals a single base transversion (A-->T) causing substitution of isoleucine by asparagine at position -30. This change disrupts the hydrophobic core of the prepeptide, a feature which is required for secretion. Thus, haemophilia in this patient is caused by a failure to secrete factor IX from the hepatocytes.

Publication types

  • Case Reports
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Child, Preschool
  • Dogs
  • Factor IX / genetics*
  • Female
  • Genetic Counseling
  • Hemophilia B / genetics*
  • Humans
  • Male
  • Mice
  • Molecular Sequence Data
  • Pedigree
  • Point Mutation*
  • Protein Precursors / genetics*
  • Rabbits
  • Sequence Homology, Amino Acid


  • Protein Precursors
  • Factor IX