« Back to Inherited Disorders

Mechanobullous Disorders

»	What are the mechanobullous disorders?
»	Do all of the blisters that form in EB develop in the same layer of the skin?
»	How is EB classified, and what are the major modes of inheritance?
»	Describe the clinical findings in EB simplex.
»	Is the cause of EB simplex known?
»	What are the clinical findings in junctional EB?
»	Is the cause of junctional EB known?
»	What are the clinical findings in dystrophic EB?
»	Is the cause of dystrophic EB known?
»	What is Kindler’s syndrome?
»	Can a definitive diagnosis of the various EB types be made on clinical presentation?
»	Are there any treatments for the mechanobullous disorders?
»	Are prenatal diagnostic techniques useful for this group of disorders?

Is the cause of dystrophic EB known?

The primary defect in dystrophic EB is an absent or structurally altered protein found in the dermis. This protein is type VII collagen, which makes up the anchoring fibrils that connect the basement membrane with the dermal collagen. Recently, mutations in the type VII collagen gene (COL7A1) located on the short arm of chromosome 3 have been found in families with both the autosomal dominant and autosomal recessive form of dystrophic EB.

Individuals with both the recessive and dominant forms are at increased risk of squamous cell carcinomas as they age. In the severe recessive form, the cumulative risks are 38.7% by age 35, 70% by age 45, and 78.7% by age 55.

Fine JD, Johnson LB, Weiner M, et al: Epidermolysis bullosa and the risk of life-threatening cancers: the National EB Registry experience, JAAD 60(2):203–211, 2009.

Masse M, Cserhalmi-Friedman PB, Falanga V, et al: Identification of a novel type VII collagen gene mutations resulting in severe recessive dystrophic epidermolysis bullosa, Clin Exp Dermatol 30:289–293, 2005.