Neurofibromatosis, Type I

Neurofibromatosis type I (NF-1) or von Recklinghausen syndrome, is a complex multi-system human disorder caused by the mutation of neurofibromin, a gene on chromosome 17 that is responsible for production of protein neurofibromin which is responsible for regulating the RAS-mediated cell growth signaling pathway. NF-1 is an autosomal dominant disorder.


The NIH criteria[1] - two of these seven "Cardinal Clinical Features" are required:

  1. Six or more café-au-lait spots over 5 mm in greatest diameter in pre-pubertal individuals and over 15 mm in greatest diameter in post-pubertal individuals. Note that multiple café-au-lait spots alone are note a definitive diagnosis of NF-1 as these spots can e caused by a number of other conditions.
  2. Two or more neurofibromas of any type or 1 plexiform neurofibroma
  3. Freckling in axillary (Crowe sign) or inguinal regions
  4. Optic nerve glioma
  5. Two or more Lisch nodules (pigmented iris hamartomas)
  6. A distinctive osseous lesion such as sphenoid dysplasia, or thinning of the long bone cortex with or without pseudarthrosis
  7. A first degree relative (parent, sibling, or offspring) with NF-1 by the above criteria


  1. Neurofibromatosis type I - Wikipedia ↩︎