Neurofibromatosis 1 & 2 (NF1, NF2)

Exam Cram

• Neurofibromatosis is genetic (autosomal dominant) disorders of growths

• 95% is Type 1 (NF1), 5% Type 2 (NF2)

• NF1 PC: cafe au lait, neurofibromas, freckling, optic glioma, lisch nodules & sphenoid dysplasia

• NF2- 90% have bilateral vestibular schwannoma and 50% bilateral meningiomas (2 by 2)

Neurofibromatosis 1 (NF1)

Background

• Mutation in NF1 gene on chromosome 17q11. 

• Autosomal dominant. 

Diagnostic criteria: 

(2 of 7)

1. Cafe au lait macules: 6 or more

2. Neurofibromas: 2 or more

3. Freckling in auxillary or inguinal regions

4. Optic glioma

5. Lisch nodules (iris hamartomas): 2 or more

6. Osseous lesion- sphenoid dysplasia

7. First degree relative with NF1 mutation

Non diagnostic features

• Learning disability (50%)

• HTN from renal artery stenosis or phaeochromocytomas

• Optic gliomas

• Vertebral dysplasia

• Intracranial tumours

• Malignant peripheral nerve tumours

Management

• Monitor

• Surgery

Neurofibromatosis 2 (NF2)

Background

• Mutation protein: merlin, neurofibromin 2

• 3% of neurofibromatosis

• Autosomal dominant

Presentation

Pneumonic: NF2 by two

• Bilateral vestibular schwannoma- sensitivity 90%, specificity very high

• Bilateral meningiomas- sensitivity 50%

Mosaic NF2

• 1/3 of NF2

• Milder symptoms

Diagnosis: 

(Require 1)

• Bilateral vestibular schwannoma < 70yrs

• Unilateral vestibular schwannoma < 70yrs & first degree relative with NF2

• Meningioma, Schwannoma, Neurofibroma, Glioma, Cerebral infarction, Cataract AND first degree relative / unilateral vestibular schwannoma & negative LZTR1 testing (Noonan Syndrome)

• Multiple meningiomas & unilateral vestibula schwanomma

• NF2 gene mutation from blood or two tumour samples

Management

• MDT: neurology, surgeons, geneticists

• Treatment: surgery, radiotherapy & chemotherapy

References

1. https://www.nhs.uk/conditions/neurofibromatosis-type-2/

Page written in 2024.