The genetic basis of epidermolysis bullosa simplex with mottled pigmentation

Jai Uttam, Elizabeth Hutton, Pierre A. Coulombe, Ingrun Anton-Lamprecht, Qian Chun Yu, Tobias Gedde-Dahl, Jo David Fine, Elaine Fuchs

Research output: Contribution to journalArticlepeer-review

Abstract

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominant skin diseases characterized by blistering, due to mechanical stress-induced degeneration of basal epidermal cells. It is now well-established that the three major subtypes of EBS are genetic disorders of the basal epidermal keratins, keratin 5 (K5) and keratin 14 (K14). Here we show that a rare subtype, referred to as EBS with mottled pigmentation (MP), is also a disorder of these keratins. Affected members of two seemingly unrelated families with EBS-MP had a C to T point mutation in the second base position of codon 24 of one of two K5 alleles, leading to a Pro:Leu mutation. This mutation was not present in unaffected members nor in 100 alleles from normal individuals. Linkage analyses mapped the defect to this type II keratin gene (peak logarithm of odds score at φ = 0 of 3.9), which is located on chromosome 12q11-q13. This provides strong evidence that this mutation is responsible for the EBS-MP phenotype. Only conserved between K5 and K6, and not among any of the other type II keratins, Pro-24 is in the nonhelical head domain of K5, and only mildly perturbs the length of 10-nm keratin filaments assembled in vitro. However, this part of the K5 head domain is likely to protrude on the filament surface, perhaps leading to additional aberrations in intermediate filament architecture and/or in melanosome distribution that are seen ultrastructurally in patients with the mutation.

Original languageEnglish (US)
Pages (from-to)9079-9084
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume93
Issue number17
DOIs
StatePublished - Aug 20 1996

Keywords

  • cytoskeleton
  • genetic disease
  • intermediate filament function
  • keratin filaments

ASJC Scopus subject areas

  • General

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