Epidermolysis bullosa

Epidermolysis bullosa (EB) is a clinically and genetically
heterogeneous group of blistering skin diseases. The main types
are designated as simplex, junctional and dystrophic, based on
ultrastructural analysis of skin biopsies. EB simplex causes
recurrent, non-scarring blisters from increased skin fragility.
The majority of cases are due to autosomal dominant mutations
in either the keratin 5 or keratin 14 genes. A rare autosomal
recessive syndrome of EB simplex and muscular dystrophy is
due to a mutation in a gene encoding plectin. Junctional EB is
characterised by extreme fragility of the skin and mucus
membranes with blisters occurring after minor trauma or
friction. Both lethal and non-lethal autosomal recessive forms
occur and mutations have been found in several genes that
encode basal lamina proteins, including laminin 5,
integrin and type XVII collagen. In dystrophic EB the
blisters cause mutilating scars and gastrointestinal strictures,
and there is an increased risk of severe squamous cell
carcinomas in affected individuals. Autosomal recessive and
dominant cases caused by mutations in the collagen
VII gene.