Characterisation of a large complex intragenic re-arrangement in the FVII gene (F7) avoiding misdiagnosis in inherited factor VII deficiency

Br J Haematol. 2007 Aug;138(3):359-65. doi: 10.1111/j.1365-2141.2007.06660.x.

Abstract

Inherited factor VII (FVII) deficiency is a rare autosomal recessive bleeding disorder mostly caused by point mutations. Large genomic re-arrangements at F7 locus could account for a fraction of mutant alleles that remain unidentified after DNA sequencing, because they escape conventional polymerase chain reaction (PCR)-based techniques. We report the first systematic screening of F7 for large re-arrangements, by semi-quantitative multiplex PCR of fluorescent fragments targeting the 9 exons and the promoter region. A well-characterised cohort of 43 unrelated patients either apparently homozygous for a F7 point mutation or carrying at least one unidentified F7 mutant allele participated in this study. Two large F7 re-arrangements were identified in two FVII-deficient pedigrees, including a discontinuous deletion involving two distinct portions of F7 whose proximal and distal end junctions were characterised. A simple and efficient method for the routine detection of gross alterations of F7, which accounted for 2.3% of mutant alleles in our sample, is now available in inherited FVII deficiency. This test should complement conventional PCR-based techniques not only in unsolved cases, but also where inheritance pattern analysis is not achievable.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • DNA Mutational Analysis
  • Exons
  • Factor VII / genetics*
  • Factor VII Deficiency / genetics*
  • Female
  • Gene Deletion
  • Gene Rearrangement*
  • Homozygote
  • Humans
  • Male
  • Pedigree
  • Point Mutation
  • Polymerase Chain Reaction / methods
  • Promoter Regions, Genetic

Substances

  • Factor VII