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Definition  

Neurofibromatosis is a genetic disorder that causes tumors in the nervous system. Tumors develop in the nerves or the tissue that surrounds the nerves, called the myelin sheath. Neurofibromatosis is divided into three types, neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis. The type is determined by the specific genes that are affected.

This article discusses NF2. These tumors tend to arise in the central nervous system. The eighth cranial nerve, which affects hearing and balance, is the most commonly involved nerve.

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Central Nervous System

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Causes  

NF is caused by a change in a specific gene. The gene normally makes proteins that help control growth in the nerves. Since the gene is defective, these proteins are not able to control growth, and tumors develop.

In many cases, the abnormal gene is inherited from a parent. A person with the inherited form of NF has a 50% chance of passing the abnormal gene to each child. Any parents, children, and siblings of an affected individual should be considered at risk for NF. However, the gene change can occur in a person with no family history of NF.

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Risk Factors  

The main risk factor for NF is having a family member with the disease.

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Symptoms  

Symptoms will depend on the exact location sand size of the tumor. Smaller tumors may not cause symptoms.

Symptoms that may occur include:

  • Hearing loss
  • Tinnitus (ringing in ears)
  • Poor balance
  • Headaches
  • Pain or numbness in the face
  • Visual problems such as double or blurry vision
  • Weakness or tingling in arms or legs
  • Bumps under skin (tumor) or small flesh colored skin flaps—in adults may also have dark, rough, hairy patches over tumor
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Diagnosis  

The doctor will ask about your medical and family medical history. A physical exam will also be done. It may take a few years before NF2