Neurofibromatosis

Question 1

Definition of NF

Answer 1

• Genetic condition that causes nerve tumours (neuromas)
• Benign but do cause structural and neurological problems

Question 2

Neurofibromatosis Type 1 (remember CRABBING for criteria)

Answer 2

• Gene on chromosome 17 that codes for a protein called neurofibromin which is a TSG - AD condition
• Criteria include:
  
  • C – Café-au-lait spots (6 or more)
  • R – Relative with NF1
  • A – Axillary or inguinal freckles
  • BB – Bony dysplasia such as Bowing of a long bone or sphenoid wing dysplasia
  • I – Iris hamartomas (Lisch nodules) (2 or more) are yellow brown spots on the iris
  • N – Neurofibromas (2 or more) or 1 plexiform neurofibroma
  • G – Glioma of the optic nerve

Question 3

Neurofibromatosis Type 2

Answer 3

• Gene on chromosome 22 codes for a protein called merlin which is a TSG - important in schwann cells, also AD condition
• Most associated with acoustic neuromas
• Symptoms include:
  
  • Hearing loss
  • Tinnitus
  • Balance problems

NB - Bilateral acoustic neuromas indicate NF type 2

Question 4

Investigation and management of NF

Answer 4

• Dignosis based on clinical criteria
• Genetic testing can be used
• X-rays for bone pain
• CT and MRI can be used to investigate lesions
• Currently no management - symptomatic control

Question 5

Complications of NF

Answer 5

• Migraines
• Epilepsy
• Renal artery stenosis causing hypertension
• Learning and behavioural problems (e.g. ADHD)
• Scoliosis of the spine
• Vision loss (secondary to optic nerve gliomas)
• Malignant peripheral nerve sheath tumours
• Gastrointestinal stromal tumour (a type of sarcoma)
• Brain tumours
• Spinal cord tumours with associated neurology (e.g. paraplegia)
• Increased risk of cancer (e.g. breast cancer)
• Leukaemia