New insights into the pathogenesis of autosomal-dominant cutis laxa with report of five ELN mutations

Bert Callewaert, Marjolijn Renard, Vishwanathan Hucthagowder, Beate Albrecht, Ingrid Hausser, Edward Blair, Cristina Dias, Alice Albino, Hiroshi Wachi, Fumiaki Sato, Robert P. Mecham, Bart Loeys, Paul J. Coucke, Anne De Paepe, Zsolt Urban

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

Autosomal dominant cutis laxa (ADCL) is characterized by a typical facial appearance and generalized loose skin folds, occasionally associated with aortic root dilatation and emphysema. We sequenced exons 28-34 of the ELN gene in five probands with ADCL features and found five de novo heterozygous mutations: c.2296-2299dupGCAG (CL-1), c.2333delC (CL-2), c.2137delG (CL-3), c.2262delA (monozygotic twin CL-4 and CL-5), and c.2124del25 (CL-6). Four probands (CL-1,-2,-3,-6) presented with progressive aortic root dilatation. CL-2 and CL-3 also had bicuspid aortic valves. CL-2 presented with severe emphysema. Electron microscopy revealed elastic fiber fragmentation and diminished dermal elastin deposition. RT-PCR studies showed stable mutant mRNA in all patients. Exon 32 skipping explains a milder phenotype in patients with exon 32 mutations. Mutant protein expression in fibroblast cultures impaired deposition of tropoelastin onto microfibril-containing fibers, and enhanced tropoelastin coacervation and globule formation leading to lower amounts of mature, insoluble elastin. Mutation-specific effects also included endoplasmic reticulum stress and increased apoptosis. Increased pSMAD2 staining in ADCL fibroblasts indicated enhanced transforming growth factor beta (TGF-β) signaling. We conclude that ADCL is a systemic disease with cardiovascular and pulmonary complications, associated with increased TGF-β signaling and mutation-specific differences in endoplasmic reticulum stress and apoptosis.

Original languageEnglish
Pages (from-to)445-455
Number of pages11
JournalHuman mutation
Volume32
Issue number4
DOIs
StatePublished - Apr 2011

Keywords

  • Aneurysm
  • CL
  • Connective tissue
  • ELN
  • Emphysema
  • Skin

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