Neurofibromatosis Type 1

Genetic condition (NF1 gene mutation) that causes tumours along the nervous system

Clinical features

≳2 of the following is diagnostic

Ocular

  • Optic glioma
    • Slow growing tumour of the optic nerve which causes fusiform enlargement, resulting in globe proptosis and an afferent pupillary defect
    • Optic nerve may be swollen (or atrophic later)
    • 30% have associated NF1
  • ≳2 Lisch nodules
    • Bilateral yellow or brown dome-shaped nodules
    • Develop during 2nd-3rd decades, eventually present in 95% of cases
notion image
Lisch nodules
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Optic glioma

Others

  • ≳6 cafe-au-lait macules
  • ≳2 neurofibromas of any type, or one plexiform neurofibroma
  • Axillary or inguinal freckling
  • Distinctive osseous lesion e.g. sphenoid dysplasia or thinning of long bone cortex, with or without pseudoarthrosis
  • First degree relative with NF1