Download GENODERMATOSES

GENODERMATOSES
DR. HADAF ABDULAMIR
ICTHYOSES
A group of disorders where the
homeostatic mechanism of epidermal
cell kinetics or differentiation is altered,
resulting in scales.
Of many types, the most common of which
are the vulgaris & the x -linked types.
The clinical differentiation between them is
difficult.
Differentiation
1) inheritance.
2) incidence
3) onset.
4) scales.
5) sites.
6) associated features.
7) prognosis.
8) treatment.
NEUROFIBROMATOSIS
Autosomal dominant.
Developmental changes in nervous
system, bone,& skin.
Of 7 types: type1( 85% of cases).
Type2: bilateral acoustic neuroma.
Type3 (mixed) & type 4 (variant)
Type 5(segmental), type 6 ( only café au
lait), & type7(late onset).
The cutaneous manifestations
1) neurofibromas: variable size, color, may
be delayed till puberty, increasing in no.
& size with age, anywhere, 90% of
women have areolar neurofibromas..
2) café au lait macules: 6 or more of 1.5
cm. dia. Is diagnostic, brownish, may
pres. at birth & almost always by 1 year.
3) axillary freckling( crowe’s sign):
extending to the neck, also genital,
inguinal & perianal areas.
Other manifestations of NF
1) Eye changes: Lisch nodules in 95% of
adult patients.
2) endocrine disorders as acromegaly,
cretinism, myxoedema.
3)bone changes: as lordosis, kyphosis,
pseudoarithrosis.
4) C.N.S.: as mental deficiency , dementia
& epilepsy.
5) Increased cancer susceptibility.
TUBEROUS SCLEROSIS
(=EPILOIA)
EPI for epilepsy
Lo I for low intellegence
A for adenoma sebaceum
Autosomal dominant of variable
penetrance.
Multiple hamartomas of skin, C.N.S.,
kidney, heart, retina & other organs.
Cutaneous manifestations
1)Ash-leaf macules: in 85%of patients,
hypopigmented, leaf shaped, linear, or
confetti like, no. 1-100, present at birth,
randomly distributed.
2)Adenoma sebaceum (angiofibroma): in
90% of patients older than 4 years, 1-3
mm in size, symmetrical, on cheeks,
nose & forehead waxy, translucent,
yellowish-red papules, may inc. in no.
Cutaneous manifestations
3)Shagreen plaque (collagenoma): in 40%
of patients in 1st decade of life, patch of
irregular, knobby skin on trunk, 1-8cm in
dia., mostly lumbosacral area.
4)Periungual fibromas( Koenen tumors):
In 50% of patients starting at puberty,
asymptomatic, small, protruding, digitate,
periungual or even subungual.
General manifestations
1) C.N.S. : mental deficiency, epilepsy,
seizures, tumors like glioma,astrocytoma
2) ophthalmological: phakomas.
3) renal tumors.
4) bone changes: as bone cysts.
Treament: removal of adenomas by
shaving, dermabrasion, & laser.
Epidermolysis bullosa
A group of rare genetic disorders where
blisters occur in response to minor
physical injury.
According to level of blistering divided into
3 main types:
1) intraepidermal.
2) junctional.
3)subepidermal.
Epidermolysis bullosa simplex
Autosomal dominant with complete pen.
Vesicles, bullae & milia at site of trauma as
joints of hands, elbows, knees &feet,
Start at birth or shortly after, few lesions.
Mucus membrane & nails are spared
Nikolisky sign is nagative.
Worse in summer.
Keratin gene mutation with abnormal
intermediate filaments, fragile basal cells
Junctional epidermolysis
bullosa( Letalis)
Rare, autosomal recessive, lamina lucida sep.
Starts at birth with sometimes fatal denudation of
the skin within months.
Generalized blistering, perioral & perinasal
granulation tissue.
No scarring or milia on healing but erosions
persist for years.
Bronchial & laryngeal involvement may cause
resp distress & death
If survive growth retardation & ref anaemia.
DYSTROPHIC
EPIDERMOLYSIS BULLOSA
Both dominant & rec. types, defective gene
encoding for collagen 7
Blisters on extensors esp. joints .
Nails may be thickened, Nikolisky often +
Healing by scar, atrophy & milia.
Mucus membrane involved with hoarseness of
voice.
Nail dystrophy, partial alopecia, contractures, claw
hand & phalangeal bone atrophy.
Cleavage in basal lamina.
TREATMENT
Prevent trauma
Decompress large blisters
Treatment of infection
In junctional we use epidermal autografts
of cultured keratinocytes.
In dystrophic: autologus meshed splithickness skin grafts & cultured
keratinocytes may be used for nonhealing skin defects.