Neurofibromatosis

Question 1

What are the types?

Answer 1

Type 1 and type 2

Question 2

What is it?

Answer 2

Genetic condition leading to benign nerve tumours throughout the nervous system

Question 3

What is the most common type?

Answer 3

Type 1

Question 4

What is the inheritance pattern of NF1

Answer 4

Autosomal dominant

Question 5

What gene is affected on which chromosome with NF1

Answer 5

Neurofibromatosis type 1 gene on chromosome 17

Question 6

What are the features of NF1?

Answer 6

CRABBING mnemonic
C - cafe au lait spots
R - relative with NF1
A - axillary or inguinal freckling
BB - bone dysplasia e.g. bowing of a long bone
I - iris hamartomas (Lisch nodules)
N - neurofibromas
G - glioma of the optic pathway

Question 7

What are neurofibromas? How many is significant?

Answer 7

Skin coloured raised nodules or papule with a smooth regular surface

Question 8

What is the management?

Answer 8

No management

Question 9

What are the complications of NF1?

Answer 9

GI stromal tumour
Malignant peripheral nerve sheath tumours
Main ones to remember

Renal artery stenosis -> HTN
Learning disability
Scoliosis
Vision loss - optic nerve gliomas
Brain tumours
Spinal cord tumours
Increased risk of cancer - breast cancer, leukaemia
epilepsy

Question 10

What chromosome is the NF2 gene found on? What protein does it code for and why is this important?

Answer 10

Chromosome 22
Merlin - tumour suppressor protein important in Schwann cells, leads to schwannomas

Question 11

What is the inheritance pattern of NF2

Answer 11

autosomal dominant

Question 12

What is NF2 associated with?

Answer 12

Bilateral acoustic neuromas