A novel deletion and two recurrent substitutions on type VII collagen gene in seven Iranian patients with epidermolysis bullosa

Objective(s): Epidermolysis bullosa is one of the most important series of mechano-bullous heritable skin disorders which is categorized into four major types according to the layer that bullae forms within basement membrane zone. In dystrophic form of the disease, blisters are made in the sublamina densa zone, at the level of type VII collagen protein which produce anchoring fibrils. Type VII collagen gene is the only responsible gene for this form. The aim of this study was to survey causative mutations of type VII collagen gene among Iranian patients with epidermolysis bullosa. Materials and Methods: For this purpose, exons ۷۳-۷۵ were investigated by polymerase chain reaction followed by direct sequencing. Results: In current study, we found three different point mutations in type VII collagen alleles in ۷ out of ۵۰ patients. Four patients were homozygous for a new deletion which resulted in frame shift (p.Pro۲۰۸۹fs). Two patients were homozygous for a recurrent glycine substitution (p.G۲۰۳۱S) and one patient was detected with an allele carrying a substitution (p.R۲۰۶۹C). Conclusion: The results emphasized heterogeneity in the type VII collagen gene and will provide a sign for early diagnosis and future study of the disease pathogenesis.

Keywords:

Dystrophic epidermolysis - bullosa , Mutation , Type VII collagen