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Neurofibromatosis Type 2 (NF2)

Genetic nervous system disorder

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Updated June 24, 2008

Neurofibromatosis is a genetic nervous system disorder that causes tumors to grow around nerves. There are three types of neurofibromatosis: type 1 (NF1), type 2 (NF2), and schwannomatosis. An estimated 100,000 Americans have a form of neurofibromatosis. Neurofibromatosis occurs in both males and females of all ethnic backgrounds.

Neurofibromatosis may either be inherited in an autosomal dominant pattern or it may be due to a new gene mutation in an individual. The gene for neurofibromatosis type 2 is located on chromosome 22.

Symptoms of neurofibromatosis type 2

Neurofibromatosis type 2 is less common than NF1. It affects about 1 in 40,000 people. Symptoms include:
  • tumors in the tissue around the eighth cranial nerve (called vestibular schwannomas)
  • hearing loss or deafness, or ringing in the ear (tinnitus)
  • tumors in the spinal cord
  • meningioma (tumor on the membrane that covers the spinal cord and brain) or other brain tumors
  • cataracts in the eyes in childhood
  • balance problems
  • weakness or numbness in an arm or leg

Diagnosis of neurofibromatosis type 2

The symptoms of neurofibromatosis type 2 are typically noticed between 18 to 22 years of age. The most frequent first symptom is hearing loss or ringing in the ears (tinnitus). To diagnose NF2, a doctor looks for schwannomas along both sides of the eighth cranial nerve, or a family history of NF2 and one schwannoma on the eighth cranial nerve before age 30. If there is no schwannoma on the eighth cranial nerve, tumors in other parts of the body and/or cataracts in the eyes in childhood could help confirm the diagnosis.

Since hearing loss can be present in neurofibromatosis type 2, a hearing test (audiometry) will be done. Brainstem auditory evoked response (BAER) tests can help determine whether the eighth cranial nerve is functioning properly. Magnetic resonance imaging (MRI), computed tomography (CT) scan, and X-rays are used to look for tumors in and around the auditory nerves. Genetic testing by blood test can be done to look for defects in the NF2 gene.

Treatment of neurofibromatosis

Doctors do not know how to stop the tumors from growing in neurofibromatosis. Surgery can be used to remove tumors that are causing pain or problems with vision or hearing. Chemical or radiation treatments may be used to reduce the size of tumors.

In NF2, if surgery done to remove a vestibular schwannoma causes hearing loss, an auditory brainstem implant may be used to improve hearing.

Other symptoms such as pain, headaches, or seizures can be managed with medications or other treatments.

Sources:

"Neurofibromatosis Fact Sheet." Disorders. 13 Dec 2007. National Institute of Neurological Disorders and Stroke. 28 May 2008.

"Learning About Neurofibromatosis." Specific Genetic Disorders. 27 Nov 2007. National Human Genome Research Institute. 28 May 2008.

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