Neurofibromatosis

Neurofibromatosis is a rare inherited disorder that results in benign tumors of the nerves and other parts of the body. Symptoms of this disease range from being virtually unnoticeable to causing neurologic problems or bone defects that affect the skull and spine.

There are two types of neurofibromatosis:

  • Type 1 (NF-1), also called von Recklinghausen's disease, causes multiple benign (noncancerous) nerve and skin tumors. NF1 is more common, occurring in 1 of every 4,000 births and affecting an estimated 100,000 patients in the United States.
  • Type 2 (NF-2), patients with NF2 usually develop benign tumors on the nerves in their ears, causing hearing loss, eventual deafness, and problems with balance. NF2 is less common, occurring in 1 of every 50,000 births.

Symptoms

NF-1

  • NF-1 may cause a change in the color of the skin. Areas of unusual skin color may appear on the trunk of the body, as well as freckling under the arms or in the groin area. Over time, the these areas may grow in size.
  • At birth or early childhood, patients may have rather large benign tumors that consist of bundles of nerves. They may also develop harmless tumor-like nodules of the colored parts of the eyes or tumors of the optic nerves, which send nerve impulses from the innermost membrane of the eyes (retinas) to the brain.
  • Over time, NF1 patients may experience abnormalities of the skeleton (thinning or overgrowth of the bones in the arms or lower leg), curvature of the spine (scoliosis), and other bone deformities.
  • A few patients may develop certain malignant (cancerous) tumors.

NF-2

  • Symptoms of NF-2 may show up during childhood, adolescence or early adulthood.
  • Depending on the location and size of the tumors, other symptoms may include problems with balance and walking, dizziness, headache, ringing in the ears, progressive hearing loss and facial weakness, numbness or pain.
  • In some cases, NF-2 causes vision problems and heightens the risk of developing specific brain and spinal cord tumors.

Causes

  • NF-1 is caused by changes in a gene (located on chromosome 17) that controls production of a protein. This gene is believed to work as a tumor suppressor. In about 50% of individuals with NF-1, the disorder results from gene mutations that happen for unknown reasons. In others with the disorder, NF-1 is an inherited trait.
  • NF-2 results from changes in a different tumor-suppressing gene (traced to chromosome 22). As with NF-1, some people with NF-2 experience a gene mutation that occurs for unknown reasons, while others inherit the trait.

Diagnosis

About one-third of the people with NF notice no symptoms. The disease is first diagnosed during a routine examination when a physician finds lumps under the skin (near nerves). In another third, the disease is first diagnosed when a person seeks cosmetic treatment for the brown skin spots or skin growths over the chest, back and other body parts. In the remaining third, NF is diagnosed when neurologic issues start.

Magnetic resonance imaging (MRI) and X-rays may be used to screen for tumors or skeletal problems.

Treatment

There is no known treatment or cure for neurofibromatosis. However, growths can usually be removed surgically or shrunk with radiation therapy. When growths are close to a nerve, surgery often requires removing the nerve.

Because neurofibromatosis is an inherited disorder, genetic counseling is recommended when a person with this disorder is considering parenthood.

For an appointment, a second opinion or more information, please call 1-800-CEDARS-1 (1-800-233-2771) or e-mail us at neurologicaldisorders@cshs.org.