Neurology - Neurofibromatosis Flashcards
What is neurofibromatosis?
Genetic condition that causes neuromas to develop throughout the nervous system
Tumours are benign but cause neurological and structural problems
Which type of neurofibromatosis is more common?
Neurofibromatosis type 1
On which chromosome is the neurofibromatosis type 1 gene located?
Chromosome 17
What protein does the neurofibromatosis type 1 gene code for?
Neurofibromin
Tumour suppressor protein
Autosomal dominant
What mnemonic is used to remember the diagnostic criteria for neurofibromatosis type 1?
CRABBING
C – Café-au-lait spots (more than 15mm diameter is significant in adults)
R – Relative with NF1
A – Axillary or inguinal freckling
BB – Bony dysplasia, such as Bowing of a long bone or sphenoid wing dysplasia
I – Iris hamartomas (Lisch nodules), which are yellow-brown spots on the iris
N – Neurofibromas
G – Glioma of the optic pathway
What are neurofibromas?
Skin-coloured, raised nodules or papules with a smooth, regular surface
What is significant about a single skin neurofibroma?
It does not indicate neurofibromatosis
If no other features
Two or more is significant
What characterises a plexiform neurofibroma?
A larger, irregular, complex neurofibroma containing multiple cell types
Plexiform neurofibroma is significant
What is the approach to managing neurofibromatosis?
Monitoring, managing symptoms, and treating complications
No treatment for underlying disease
What are some complications associated with neurofibromatosis?
- Migraines
- Epilepsy
- Renal artery stenosis - hypertension
- Learning disability
- Behavioural problems
- Scoliosis
- Vision loss - optic nerve gliomas
- Malignant peripheral nerve sheath tumours
- Gastrointestinal stromal tumour
- Brain tumours
- Spinal cord tumours - paraplegia
- Increased risk of cancer - breast cancer and leukaemia
What are the two unique complications of NF1?
Malignant peripheral nerve sheath (MPNST)
Gastrointestinal stromal tumours (GIST)
On which chromosome is the neurofibromatosis type 2 gene located?
Chromosome 22
What protein does the neurofibromatosis type 2 gene code for?
Merlin
Tumour suppressor protein for Schwann cells
Leads to schwannomas
Autosomal dominant
What tumours are particularly associated with neurofibromatosis type 2?
Acoustic neuromas
Bilateral acoustic neuroma = NFT2
What is a potential risk of surgery for acoustic neuromas?
Permanent nerve damage
