Novel and recurrent mutations in the integrin beta 4 subunit gene causing lethal junctional epidermolysis bullosa with pyloric atresia


Iacovacci S., Cicuzza S., Odorisio T., Silvestri E., Kayserili H., Zambruno G., ...More

EXPERIMENTAL DERMATOLOGY, vol.12, no.5, pp.716-720, 2003 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 12 Issue: 5
  • Publication Date: 2003
  • Doi Number: 10.1034/j.1600-0625.2003.00052.x
  • Journal Name: EXPERIMENTAL DERMATOLOGY
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.716-720

Abstract

In this study we examined two unrelated patients affected with the lethal variant of junctional epidermolysis bullosa with pyloric atresia (PA-JEB) who were found to carry mutations in the integrin beta4 subunit gene (ITGB4). Although in both patients Northern blot analysis showed only a 50% reduction in the level of ITGB4 transcript, a complete lack ( patient 1) or a strong reduction ( patient 2) of b4 immunoreactivity was observed in the skin. Using immunoprecipitation analysis, integrin b4 could not be visualized in patient 1 cells while a markedly reduced amount (similar to20%) of normal sized beta4 chains was detected in patient 2. These data suggested the presence of ITGB4 mutations that interfere with both mRNA and protein stability. Using molecular analysis, patient 1 was shown to be a compound heterozygous for a single amino acid deletion (DeltaN318) and a not yet identified mutation that induces a very rapid decay of the encoded mRNA transcript. Patient 2 was, instead, a compound heterozygous for a novel 4-bp tandem duplication (4298 - 4299ins4) and a previously described missense mutation (R252C). Our data support the notion that PA-JEB lethal phenotypes associated with a markedly decreased/absent alpha6beta4 expression can be due not only to the presence of null alleles, but also to specific mutations leading to protein instability and/or altered function.