Differences in recurrent COL7A1 mutations in dystrophic epidermolysis bullosa: ethnic-specific and worldwide...

Dystrophic epidermolysis bullosa (DEB) is caused by mutations in the gene encoding type VII collagen (COL7A1). Although most COL7A1 mutations are unique to individual families, small numbers of mutations are recurrent. The recurrent mutations R578X, 7786delG, and R2814X seem to be exclusive to a specific ethnic group, the British population. The mutations 5818delC, 6573+1G-->C, and E2857X are present only in individuals of Japanese ethnic origin. On the other hand, the mutations 425A-->G and G2043R have been found in several different ethnic groups. The purpose of this study was to clarify whether these recurrent mutations are also found in patients of other ethnic groups with DEB, mainly Asian patients. We demonstrated the absence of the recurrent mutations R578X, 7786delG, and R2814X in 42 non-British patients with DEB and detected the mutations 425A-->G in a French patient and G2043R in Japanese and Chinese patients with DEB. The mutations 5818delC, 6573+1G-->C, and E2857X were detected in 11 Japanese patients (13 alleles) with DEB. Our results confirm that R578X, 7786delG, and R2814X mutations are specifically limited to British patients, and the mutations 5818delC, 6573+1G-->C, and E2857X are frequent in Japanese patients. On the other hand, the mutations 425A-->G and G2043R can be found in different ethnic groups. In conclusion, our results further support the notion that recurrent mutations can be classified into two types, ethnic-specific mutation and worldwide mutation.