Truncated typeXVII collagen expression in a patient with non-herlitz junctional epidermolysis bullosa caused by a homozygous splice-site mutation

Lab Invest. 2001 Jun;81(6):887-94. doi: 10.1038/labinvest.3780297.

Abstract

Type XVII collagen (180-kDa bullous pemphigoid antigen) is a structural component of hemidesmosomes. Mutations in the type XVII collagen gene (COL17A1) have been established to be the molecular basis of non-Herlitz junctional epidermolysis bullosa (JEB-nH), an inherited skin blistering disorder. Here we report for the first time truncated type XVII collagen expression, caused by homozygosity for a COL17A1 donor splice-site mutation (4261+1 g --> c), which was identified by PCR amplification on genomic DNA. By RT-PCR and sequencing of cDNA derived from mRNA from the patient's cultured keratinocytes, we provide evidence of cryptic splicing and exon skipping, most abundantly of exon 52. JEB-nH patients with COL17A1 splice-site mutations resulting in an exon skip often have no immunologically detectable type XVII collagen. However, in our patient with the generalized atrophic benign epidermolysis bullosa subtype, a small amount of type XVII collagen was detectable in the skin, and immunoblotting of cultured keratinocytes revealed that the 180-kDa protein was 10 kDa shorter. We hypothesize that the function of this truncated type XVII collagen polypeptide, which is expressed at low levels, is impaired, explaining the JEB-nH phenotype.

Publication types

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

MeSH terms

  • Aged
  • Base Sequence / genetics
  • Collagen / genetics
  • Collagen / metabolism*
  • DNA, Recombinant*
  • Epidermolysis Bullosa / genetics*
  • Epidermolysis Bullosa / metabolism*
  • Female
  • Fluorescent Antibody Technique
  • Homozygote*
  • Humans
  • Immunoblotting
  • Mutation*
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • RNA, Messenger / metabolism

Substances

  • DNA, Recombinant
  • Peptide Fragments
  • RNA, Messenger
  • Collagen