Achondroplasia, Birthmarks Flashcards
What is achondroplasia?
An autosomal dominant disorder associated with short stature.
Cause of achondroplasia?
Mutation in the fibroblast growth factor receptor 3 (FGFR-3) gene.
This results in abnormal CARTILAGE.
Features of achondroplasia?
- short limbs (rhizomelia) with shortened fingers (brachydactyly)
- large head with frontal bossing and narrow foramen magnum
- midface hypoplasia with a flattened nasal bridge
- ‘trident’ hands
- lumbar lordosis
What is the main risk factor for achondroplasia?
Advancing paternal age at the time of conception
What is spina bifida?
A neural tube defect.
Name some birth marks (4)
1) Stork mark (AKA salmon patch)
2) Port wine stain
3) Strawberrry naevus
4) Congenital dermal melanocytosis/slate grey naevus
Describe stork marks
Where are stork marks typically seen?
Pink and blotchy.
Commonly found on forehead, eyelids and nape of neck.
How to stork marks typically progress?
They usually fade over a few months, though marks on the neck may persist.
What can make stork marks worse?
Crying/straining
Describe port wine stains
Vascular birthmarks that tend to be unilateral. They are deep red or purple in colour.
How do port wine stains progress?
They do not spontaneously resolve, and in fact often darken and become raised over time
Mx of port wine stains?
a) cosmetic camouflage
b) laser therapy (multiple sessions are required)
What syndrome can port wine stains be part of?
Sturge-Weber syndrome
What is a strawberry naevus?
Infantile haemangioma
Usually not present at birth but may develop rapidly in the first month of life.
Presentation of strawberry naevus?
They appear as erythematous, raised and multilobed tumours.
How do strawberry naevus progress?
Typically they increase in size until around 6-9 months before regressing over the next few years (around 95% resolve before 10 years of age).
Common sites for strawberry naevus?
Common sites include the face, scalp and back.
Rarely they may be present in the upper respiratory tract leading to potential airway obstruction
What are 4 potential complications of strawberry naevus?
1) mechanical e.g. Obstructing visual fields or airway
2) bleeding
3) ulceration
4) thrombocytopaenia
1st line pharmacological management of strawberry naevus (if in sensitive site/ulcerated)?
Propanolol
What is congenital dermal melanocytosis/slate grey naevus?
Melanocytes in the deep dermis.
More common in darker skins.
Where is congenital dermal melanocytosis/slate grey naevus typically found?
Over lower back/buttocks
What is a key differential for congenital dermal melanocytosis/slate grey naevus?
Bruising
