“…Furthermore, severe phenotypes do not always occur when other PTC mutations are coupled with p.Glu2857X, since 18 M. Saito et al patients 2, 3 and 4 possessed additional PTC-causing mutations c.5818delC, c.6573 + 1G > C, and c.8008delT, respectively, but presented with moderate clinical phenotypes. The six patients, including the three previously reported cases [18,19], appear to share similar genetic features regarding type VII collagen synthesis, and the phenotypic variability may be attributed to factors such as age, environmental or genetic background. A contribution of factors other than COL7A1 mutations to DEB phenotypes has also been proposed in a previous study [22], in which a glycine substitution mutation led to marked interfamiliar clinical heterogeneity in DDEB.…”