Mechanisms of natural gene therapy in dystrophic epidermolysis bullosa Articles uri icon

publication date

  • January 2014

start page

  • 2097

end page

  • 2104

issue

  • 8

volume

  • 134

international standard serial number (ISSN)

  • 0022-202X

electronic international standard serial number (EISSN)

  • 1523-1747

abstract

  • Revertant mosaicism has been reported in several inherited diseases, including the genetic skin fragility disorder epidermolysis bullosa (EB). Here, we describe the largest cohort of seven patients with revertant mosaicism and dystrophic EB (DEB), associated with mutations in the COL7A1 gene, and determine the underlying molecular mechanisms. We show that revertant mosaicism occurs both in autosomal dominantly and recessively inherited DEB. We found that null mutations resulting in complete loss of collagen VII and severe disease, as well as missense or splice-site mutations associated with some preserved collagen VII function and a milder phenotype, were corrected by revertant mosaicism. The mutation, subtype, and severity of the disease are thus not decisive for the presence of revertant mosaicism. Although collagen VII is synthesized and secreted by both keratinocytes and fibroblasts, evidence for reversion was only found in keratinocytes. The reversion mechanisms included back mutations/mitotic recombinations in 70% of the cases and second-site mutations affecting splicing in 30%. We conclude that revertant mosaicism is more common than previously assumed in patients with DEB, and our findings will have implications for future therapeutic strategies using the patient's naturally corrected cells as a source for cell-based therapies.

keywords

  • revertant mosaicism ; mitotic recombination ; col17a1 mutations ; col7a1 mutation ; stem-cells ; classification ; epidermis; cohort