Neurofibromatoses are genetic disorders of the nervous system. Mainly, these disorders affect the growth and development of nerve cell tissue. The disorders are known as neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). NF1 is the more common type of neurofibromatosis.
NF1 is also called von Recklinghausen NF or Peripheral NF. It is characterized by multiple cafe-au-lait spots and neurofibromas on or under the skin. Enlargement and deformation of bones and curvature of the spine (scoliosis) may also occur. Occasionally, tumors may develop in the brain, on cranial nerves, or on the spinal cord. About 50% of people with NF1 also have learning disabilities.
NF2 is also called Bilateral Acoustic NF (BAN). This disease is much more rare than NF1 and is characterized by multiple tumors on the cranial and spinal nerves. In NF2, there are additional lesions of the brain and spinal cord. Tumors affect both of the auditory nerves. Hearing loss beginning in the teens or early twenties is generally the first symptom.
What causes Neurofibromatosis?
Neurofibromatosis is often inherited (passed on by family members through our genes), but 30% to 50% of people newly diagnosed with the disorder have no family history of the condition, which can arise spontaneously through a mutation (change) in the genes. Once this change has taken place, the mutant gene can be passed on to future generations.
People with NF1 will often display these symptoms:
- Several (usually 6 or more) café au lait spots (patches of tan or light brown skin).
- Multiple freckles in the armpit or groin area.
- Tiny growths in the iris (colored area) of the eye. These are called Lisch nodules and usually do not affect eyesight.
- Neurofibromas (soft, fleshy growths) that occur on or under the skin, sometimes even deep within the body. These are benign (harmless) tumors, however, in rare cases they can turn malignant or cancerous.
- Bone deformities including a twisted spine (scoliosis) or bowed legs.
- Tumors along the optic nerve, which may cause eyesight problems.
- Nerve-related pain
People with NF2 often display the following symptoms:
- Loss of hearing
- Weakness of the muscles of the face
- Poor balance
- Uncoordinated walking
- Cataracts (cloudy areas on the lens of the eye) that develop at an unusually early age
Neurofibromatosis is diagnosed using a number of tests, including:
- Physical examination
- Medical history
- Family history
- Computerized tomography (CT) scans
- Magnetic resonance imaging (MRI)
- Biopsy of neurofibromas
- Eye tests
- Tests for particular symptoms, such as hearing or balance tests
- Genetic testing (available for families with documented cases of NF1 and NF2)
In diagnosing NF1, doctors use the following criteria:
- Six or more café-au-lait spots that are 1.5 cm or larger in post-pubertal individuals or 0.5 cm or larger in pre-pubertal individuals
- Two or more neurofibromas (tumor that develops from the cells and tissues that cover nerves) of any type or one or more plexiform neurofibroma (nerve that has become thick and misshapen due to the abnormal growth of cells and tissues that cover the nerve)
- Freckling in the armpit or groin
- Optic glioma (tumor of the optic pathway)
- Two or more Lisch nodules (benign iris hamartomas)
- A distinctive bony lesion, dysplasia of the sphenoid bone or dysplasia or thinning of long bone cortex
- A first-degree relative with NF1
In diagnosing NF2, doctors use the following criteria:
- Bilateral (on both sides) vestibular schwannomas, also known as acoustic neuromas. These are benign tumors that develop from the balance and hearing nerves supplying the inner ear.
Family history of NF2 (first degree family relative) plus unilateral (on one side) vestibular schwannomas or any two health conditions including the following:
- Meningioma (tumor that occurs in the meninges, the membranes that cover and protect the brain and spinal cord)
- Glioma (cancer of the brain that begins in glial cells, which are those that surround and support nerve cells)
- juvenile cataracts
There is no cure for neurofibromatosis. Treatments for both types of neurofibromatosis concentrate on controlling symptoms. There is no standard treatment for NF and many symptoms, such as café au lait spots, do not need treatment. When treatment is necessary, options may include:
- Surgery to remove problematic growths or tumors
- Treatment may also include chemotherapy or radiation if a tumor has turned malignant or cancerous
- Surgery may also help some bone problems, like scoliosis
- Therapy (including physical therapy, counseling or support groups)
- Cataract removal surgery
- Aggressive treatment of associated pain
The outlook for a person with neurofibromatosis depends on the type. NF1 may reduce life expectancy by up to 15 years, usually because of malignant tumors. Early diagnosis and treatment can reduce mortality rates.
The outlook for people with NF2 depends of the person’s age at the disease’s onset and on the number and location of tumors. Prompt diagnosis and treatment can improve life expectancy to more than 15 years following diagnosis.
- Learn more about neurofibromatosis and treatment options available at Cleveland Clinic
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