Neurofibromatosis

Question 1

Define:

Answer 1

Autosomal dominant genetic disorder affecting cells of the neural crest origin; resulting in the development of multiple neurocutaenous tumours.

Question 2

Aetiology/risk factors:

Answer 2

Mutations in tumour supressor genes.

Type 1 is a mutation in NF1 on Chr 17 affecting peripheral and spinal neurofibromas

Type 2 is a mutation in NF2 on Chr 22 leading to schwannomas, meningiomas, gliomas and cataracts.

Question 3

Symptoms of type 1:

Answer 3

\+ve FHx
Headaches 
Seizures 
Learning difficulties 
Skin lesions
Disturbed vision (due to optic gliomas)
Precocious puberty (due to lesions in the pituitary gland)

Question 4

Symptoms of type 2:

Answer 4

Headaches 
Hearing loss
Tinnitus 
Facial pain/numbness 
Balance problems

Question 5

Signs of type 1:

Answer 5

5+ cafe au lait spots >5mm (in pre-pubertal)
5+ cafe au lait spots >15mm (in post-pubertal)

Neurofibromas - may appear as cutaneous nodules

freckling in the armpit or groin

Lisch nodules in the eye

Spinal scolosis

Short stature

Question 6

Signs of type 2:

Answer 6

Few or no skin lesions

Sensineural deafness with facial nerve palsy or cerebellar signs

Question 7

Investigations:

Answer 7

Full body examination for skin lesions

Opthalmological assessment

Audiometry

MRI brain and spinal cord –> vestibular schwannomas, meningiomas and nerve rotts neurofibromas

Skull x-ray

Genetic testing