Corneal recurrent erosions and mutations in the gene COL7A1

Abstract

Abstract: : Purpose:To describe a family with recurrent corneal erosions caused by a mutation in the COL7A1 gene. Methods:We report a family (two affected members) with autosomal recessive dystrophic epidermolysis bullosa associated with non traumatic recurrent corneal erosions and superficial corneal opacities. Results:Slit lamp examination revealed bilateral map–dot figerprint like lesions as well as sub–epithelial haziness. Genomic DNAs were extracted from leukocytes of the peripheral blood. Using appropriate primers, we amplified exons of the COL7A1 gene by polymerase chain reaction and directly sequenced the products. Conclusions:Recurrent corneal erosion occurs when there is a deficiency of adherence between the basement membrane of the corneal epithelium and the underlying Bowman’s layer that leads to recurrent separation of the epithelium. COL7A1 encodes the alpha chain of type VII collagen. The type VII collagen fibril, composed of three identical alpha collagen chains, is restricted to the basement zone beneath stratified squamous epithelia. It functions as an anchoring fibril between the external epithelia and the underlying stroma. In this family mutations in COL7A1 gene are associated with corneal recurrent erosions. The etiology of non traumatic epithelial recurrent erosions syndrome remains unknown. A genetic screening of corneal collagen genes mutations may help in understanding the molecular defects linked with this syndrome.

Keywords: cornea: epithelium • degenerations/dystrophies • genetics