2. introduction
Medical significance of
hemidesmosomes mutations in
integrin leads to types of
epidermolysis bullosa, a skin blistering
disorder.
Junctional EB is an inherited disease
affecting laminin & collagen. This
disease is characterized by blister
formation within the lamina lucida of
the basement membrane zone.
3. And is inherited in an autosomal
recessive manner ,it also presents
with blisters at the site of friction,
especially on the hands & feet, and
has variants that can occur in children
& adults. Lees than one /million
people is estimated to have this form
of EB.
4. what is a hemidesmosome ?
It is a half desmosome that connect a
cell, through a plaque, to the basal
lamina.
Plaque composed of plectin, integrins,
a family of transmembrane proteins
that is
◦ a receptor site for laminin and type IV
collagen of the basal lamina, keratin
tonofilaments insert into plaque.
5. What Is an Epidermolysis
Bullosa ?
Is a group of inherited bullous
disorders characterized by blister
formation in response to mechanical
trauma, It is a result of a defect in
anchoring between
the epidermis and dermis ,Its severity
ranges from mild to lethal.
6. pathogenesis :
EB resulting from genetic mutation in
one of 18 genes, these mutation or
errors in the genetic code ,do not allow
the body to either produce an essential
protein or,
Produce a working form of the protein
,thus resulting in extremely fragile
skin.
EB can also be an autoimmune
disease in which the body produces
antibodies to the structural
7. So, EB is classified into 3 major
categories+ other according to the site
and cause :
1. EB simplex (intraepidermal skin
separation)»»»»keratin 5,14
2. Junctional EB (skin separation in
lamina lucida)»»»» laminin5
3. Dystrophic EB (sublamina densa
separation)»»»» collagen iv,vii
4. Hemidesosomal EB (blistering at the
hemidesmosomal
level)»»»»integrin,plectin
8. EB simplex usually is associated with
little or no extra-cutaneous
involvement, while the more sever
hemidesomsomal , junctional and
dystrophic forms may produce
significant multiorgan system
involvement.
9. symptoms
Fluid filled blisters on the skin
especially on the hands & feet due to
friction
Internal blistering including on vocal
cords ,esophagus &upper airway
Skin thickening on the palms and the
sole of the feet
Scalp blistering , scarring & hair loss
(scarring alopecia)
10. Dental problems, such tooth decay
from poorly formed enamel
Difficulty swallowing (dysphagia)
11. complications
Infection : blister is exposed to
bacterial infection
Sepsis : massive infection Enter blood
stream , sepsis is rapidly progressing
that cause shock & organ failure
Deformities : sever form of EB can
cause fusion of fingers or toes,
contracture of joints
Loss of fingernails &toenails
12. Malnutrition and anemia
Dehydration
Constipation
Eye disorder
Skin cancer :squamous cell ca.
Death : infants with sever form of JEB
are at risk of infection & loss of body
fluids
13. diagnosis
Based on clinical picture &
histopathology, determines the level of
disease.
Age
Microscope
Immunohistochemistry
Western blot
DNA sequence
14. Treatment and outcome
Treatment of EB aims to prevent
complications and ease the pain of
blisters with appropriate wound care.
New treatments (gene, protein therapy
) may provide solution to the skin
fragility.
condition often progresses despite
treatment ,sometimes causing serious
complications & death.
