Availability of mRNA Obtained from Peripheral Blood Mononuclear Cells for Testing Mutation Consequences in Dystrophic Epidermolysis Bullosa

Dystrophic epidermolysis bullosa (DEB) is an inheritable blistering disease caused by mutations in COL7A1, which encodes type VII collagen. To address the issue of genotype-phenotype correlations in DEB, analyzing the consequences of COL7A1 mutations using mRNA is indispensable. Herein we established a novel method for testing the effect of mutations in DEB using COL7A1 mRNA extracted from peripheral blood mononuclear cells (PBMCs). We investigated the consequences of four COL7A1 mutations (c.6573 + 1G > C, c.6216 + 5G > T, c.7270C > T and c.2527C > T) in three Japanese individuals with recessive DEB. The novel method detected the consequences of two recurrent COL7A1 mutations (c.6573 + 1G > C, c.6216 + 5G > T) and a novel COL7A1 mutation (c.7270C > T) accurately. In addition, it detected aberrant splicing resulting from a COL7A1 mutation (c.2527C > T) which was previously reported as a nonsense mutation. Furthermore, we revealed that type VII collagen-expressing cells in PBMCs have similar cell surface markers as mesenchymal stem cells; they were CD105(+), CD29(+), CD45(−), and CD34(−), suggesting that a small number of mesenchymal stem cells or mesenchymal stromal cells are circulating in the peripheral blood, which enables us to detect COL7A1 mRNA in PBMCs. Taken together, our novel method for analyzing mutation consequences using mRNA obtained from PBMCs in DEB will significantly contribute to genetic diagnoses and novel therapies for DEB.