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Genetic disorder characterized by cutaneous blistering
and scarring following minor trauma.
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More than 20 different subtypes of the disease are
grouped into three main categories: epidermolysis bullosa simplex (EBS),
dystrophic epidermolysis bullosa (DEB), and junctional epidermolysis bullosa
(JEB).
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Seems to vary widely, depending on the country, from as
high as 1:12,500 in the United States and 1:17,000 in the United Kingdom to
1:300,000 in Canada. The incidence of DEB and EBS is approximately 2 in
100,000, for each of them.
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DEB has two modes of transmission that are
autosomal dominant and more frequently autosomal recessive. EBS is inherited
as an autosomal dominant trait. JEB form is an autosomal recessive trait.
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In EBS, skin separation occurs at the level of mid
basal cells and is most commonly associated with mutations affecting the
genes responsible for keratins 5 and 14. The molecular background of JEB is
highly variable and most likely represents a collection of different
diseases. The separation of the skin layers with blister formation occurs in
the lamina lucida. The responsible mutations have been assigned to the genes
coding for the laminin 5 subunits, collagen XVII, and α6 and
β4 integrin. DEB is associated with mutations in the gene coding
for collagen type VII (COL7A1), which is a protein that anchors the lamina
densa within the superficial dermis.
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Based on the clinical features of blisters and scarring
associated with minor trauma of the skin, oropharynx, and esophagus.
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In general, patients are very sensitive to touch
because frictional or shearing forces damage their skin and lead to
blistering and scarring. These blisters can be very painful (and sometimes
itchy) and often are present at birth or shortly thereafter.
Application of
direct pressure (without shearing forces), such as related to blood pressure
measurement, is not as damaging. Affected patients may present with severe
syndactyly of their fingers and toes (so-called “pseudosyndactyly” or
“mitten deformity”) and contractures of their limbs caused by scarring as
a consequence of the disease. ...