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Genetic and Rare Diseases Information Center (GARD)

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Neurofibromatosis type 1

Other Names for this Disease
  • NF1
  • Recklinghausen's disease
  • Type 1 neurofibromatosis
  • Von Recklinghausen disease
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Your Question

I was recently diagnosed with neurofibromatosis type 1. Due to my mild symptoms, I believe that I may have segmental neurofibromatosis. Is there a test which can confirm this diagnosis?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is segmental neurofibromatosis?

Segmental or regional neurofibromatosis (also known as neurofibromatosis type 5) is a rare form of neurofibromatosis where only part of the body is affected.  Individuals with segmental neurofibromatosis do not usually have café-au-lait spots which are typically found in people with neurofibromatosis type 1. Most people with segmental neurofibromatosis have no family history of the condition.[1][2]
Last updated: 10/11/2013

What causes segmental neurofibromatosis?

In some cases, the restriction of features to one part of the body may be due to chance in a person with a mild form of neurofibromatosis type 1. In other individuals, segmental neurofibromatosis is caused by only some cells in the body having a mutation in the NF1 gene (called mosaicism).[2] Segmental neurofibromatosis is thought to occur when a mutation in the NF1 gene develops sometime after conception, as opposed to being inherited from a parent.[1]
Last updated: 6/6/2012

How is segmental neurofibromatosis inherited?

Individuals with segmental neurofibromatosis usually have a low risk of passing this disease to their children because the mutation is not typically present in egg or sperm cells.[1] However, some individuals with segmental neurofibromatosis have had children with neurofibromatosis type 1.[1][2]
Last updated: 6/6/2012

Is there a test which can distinguish between neurofibromatosis type 1 (NF1) and segmental neurofibromatosis?

An individual with segmental neurofibromatosis has the NF1 gene mutation in only some cells of their body. On the other hand, an individual with neurofibromatosis type 1 will have the mutation in all of their cells.[3]

To test for neurofibromatosis type 1, a blood test can be done to look for a mutation in the NF1 gene. For an individual with segmental neurofibromatosis, the blood test may not be able to find a mutation. Instead of using blood, a small sample (biopsy) of affected skin or tumor can be tested for the NF1 mutation.[3]
Last updated: 6/6/2012