Dystrophic EB, also called dermolytic EB, is caused by a mutation in the collagen VII gene. Generally, this mutation decreases the ability of the anchoring fibrils to hold together the layers of the skin. The degree of skin fragility depends on the degree of abnormality of the anchoring fibrils.
There are two main subtypes of dystrophic EB, dominant dystrophic EB (DDEB) and recessive dystrophic EB (RDEB), and several minor subtypes. The various subtypes of RDEB vary in severity. The disorder may be so mild as to only present an inconvenience to the affected individual or so severe that it is life-altering. National EB Registry data suggests that family members often have similar clinical presentations. Although there always are individual differences, the majority of family members tend to look alike in regard to their EB.