genetic skin conditions Flashcards
What is tuberose sclerosis?
Autosomal dominant condition of variable severity, characterised by a range of benign tumours in various organ systems of the body
What are some presentations of tuberose sclerosis?
- Ash-leaf macule (Depigmented)
- Infantile seizures
- Horizontal nail ridging
- Hamartoma formation
- Shagreen patches
- Enamel pitting
What sign of tuberose sclerosis is shown?
Ash-leaf macule
What sign of tuberose sclerosis is shown?
Enamel pitting
What sign of tuberose sclerosis is shown?
Shagreen patches
What are some hamartomas commonly formed in tuberose sclerosis>
- Periungual fibromas
- Facial angiofibromas (Adenoma sebaceum)
- Angiomyolipoas (Heart, lungs, kidneys)
- Bone cysts
What causes infantile seizures and mental impairment in tuberose sclerosis?
Cortical tubers or calcification of falx cerbri
Describe the genetics of tuberose sclerosis?
This is an autosomal dominant condition, caused by mutation in one of 2 genes (TSC1 and TSC2)
These code for tuberin and hamartin and are tumour regulating genes
What is a risk factor of tuberose sclerosis?
Older fathers
What is meant by a dominant-negative disease mechanism?
Mutant protein stops normal protein working
What is meant by haploinsufficiency?
Only one copy of working gene leads to reduced protein function
What is epidermolysis bullosa?
Group of inherited disorders with blister formation in response to mechanical trauma
What are the 3 main types of epidermolysis bullosa?
- Simplex - Affects epidermis
- Junctional - Affects dermo-epidermal junction
- Dystrophic - Affects dermis
Which forms of epidermolysis bullosa have multi-organ, extra-dermal effects?
Junctional and dystrophic
Describe the genetics of epidermolysis bullosa
This can be dominant or recessive and involves mutations in >10 genes, involved in skin structure and adhesion
