GENETIC-BASIS OF DOMINANTLY INHERITED TRANSIENT BULLOUS DERMOLYSIS OFTHE NEWBORN - A SPLICE-SITE MUTATION IN THE TYPE-VII COLLAGEN GENE

Transient bullous dermolysis of the newborn (TBDN) is a blistering dis ease evident at birth or shortly thereafter, but the blistering tenden cy decreases with advancing age. The tissue separation in TBDN is belo w the lamina densa, and electron microscopy has revealed abnormalities in anchoring fibrils. Immunofluorescence staining demonstrates intrac ellular accumulation of type VII collagen. In this study, we report a G-to-C transversion mutation in the last nucleotide of intron 35 of th e type VII collagen gene (COL7A1) in a family with autosomal dominant TBDN in three generations. This nucleotide substitution abolishes the obligatory consensus 3'-acceptor splice site, predicting in-frame skip ping of exon 36. Thus, TBDN in this family is caused by a mutation in COL7A1, and is therefore allelic with other variants of dominant dystr ophic epidermolysis bullosa.