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Neurofibromatosis

Medically reviewed by Drugs.com. Last updated on Jan 21, 2021.

Overview

Neurofibromatoses are a group of genetic disorders that cause tumors to form on nerve tissue. These tumors can develop anywhere in the nervous system, including the brain, spinal cord and nerves. There are three types of neurofibromatosis: neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2) and schwannomatosis. NF1 is usually diagnosed in childhood, while NF2 and schwannomatosis are usually diagnosed in early adulthood.

The tumors in these disorders are usually noncancerous (benign), but sometimes can become cancerous (malignant). Symptoms are often mild. However, complications of neurofibromatosis can include hearing loss, learning impairment, heart and blood vessel (cardiovascular) problems, loss of vision, and severe pain.

Neurofibromatosis treatment focuses on encouraging healthy growth and development in children who are affected by the disorder and on early management of complications. When neurofibromatosis causes large tumors or tumors that press on a nerve, surgery can reduce symptoms. Some people may benefit from other therapies, such as stereotactic radiosurgery or medications to control pain. A new medication is available to treat tumors in children, and other new treatments are being developed.

Symptoms

There are three types of neurofibromatosis, each with different signs and symptoms.

Neurofibromatosis 1

Neurofibromatosis 1 (NF1) is usually diagnosed during childhood. Signs are often noticeable at birth or shortly afterward and almost always by age 10. Signs and symptoms are often mild to moderate, but can vary in severity.

Signs and symptoms include:

  • Flat, light brown spots on the skin (cafe au lait spots). These harmless spots are common in many people. Having more than six cafe au lait spots suggests NF1. They are usually present at birth or appear during the first years of life. After childhood, new spots stop appearing.
  • Freckling in the armpits or groin area. Freckling usually appears by ages 3 to 5. Freckles are smaller than cafe au lait spots and tend to occur in clusters in skin folds.
  • Tiny bumps on the iris of the eye (Lisch nodules). These harmless nodules can't easily be seen and don't affect vision.
  • Soft, pea-sized bumps on or under the skin (neurofibromas). These benign tumors usually develop in or under the skin, but can also grow inside the body. Sometimes, a growth will involve many nerves (plexiform neurofibroma). Plexiform neurofibromas, when located on the face, can cause disfigurement. Neurofibromas may increase in number with age.
  • Bone deformities. Abnormal bone development and a deficiency in bone mineral density can cause bone deformities such as a curved spine (scoliosis) or a bowed lower leg.
  • Tumor on the optic nerve (optic glioma). These tumors usually appear by age 3, rarely in late childhood and adolescence, and almost never in adults.
  • Learning disabilities. Impaired thinking skills are common in children who have NF1 but are usually mild. Often there is a specific learning disability, such as a problem with reading or mathematics. Attention-deficit/hyperactivity disorder (ADHD) and speech delay also are common.
  • Larger than average head size. Children with NF1 tend to have a larger than average head size due to increased brain volume.
  • Short stature. Children who have NF1 often are below average in height.

Neurofibromatosis 2

Neurofibromatosis 2 (NF2) is much less common than NF1. Signs and symptoms of NF2 usually result from the development of benign, slow-growing tumors in both ears (acoustic neuromas), which can cause hearing loss. Also known as vestibular schwannomas, these tumors grow on the nerve that carries sound and balance information from the inner ear to the brain.

Signs and symptoms generally appear during the late teen and early adult years, and can vary in severity. Signs and symptoms can include:

  • Gradual hearing loss
  • Ringing in the ears
  • Poor balance
  • Headaches

Sometimes NF2 can lead to the growth of schwannomas in other nerves, including the cranial, spinal, visual (optic) and peripheral nerves. People who have NF2 may also develop other benign tumors.

Signs and symptoms of these tumors can include:

  • Numbness and weakness in the arms or legs
  • Pain
  • Balance difficulties
  • Facial drop
  • Vision problems or cataracts
  • Seizures
  • Headache

Schwannomatosis

This rare type of neurofibromatosis usually affects people after age 20. Symptoms usually appear between ages 25 and 30. Schwannomatosis causes tumors to develop on the cranial, spinal and peripheral nerves — but rarely on the nerve that carries sound and balance information from the inner ear to the brain. Tumors don't usually grow on both hearing nerves, so people who have schwannomatosis don't experience the same hearing loss as people who have NF2.

Symptoms of schwannomatosis include:

  • Chronic pain, which can occur anywhere in the body and can be disabling
  • Numbness or weakness in various parts of the body
  • Loss of muscle

When to see a doctor

See your doctor if you or your child develop signs or symptoms of neurofibromatosis. The tumors associated with neurofibromatosis are often benign and slow growing.

Causes

Neurofibromatosis is caused by genetic defects (mutations) that either are passed on by a parent or occur spontaneously at conception. The specific genes involved depend on the type of neurofibromatosis:

  • NF1. The NF1 gene is located on chromosome 17. This gene produces a protein called neurofibromin that helps regulate cell growth. The mutated gene causes a loss of neurofibromin, which allows cells to grow uncontrolled.
  • NF2. The NF2 gene is located on chromosome 22, and produces a protein called merlin (also called schwannomin), which suppresses tumors. The mutated gene causes a loss of merlin, leading to uncontrolled cell growth.
  • Schwannomatosis. So far, two genes are known to cause schwannomatosis. Mutations of the genes SMARCB1 and LZTR1, which suppress tumors, are associated with this type of neurofibromatosis.

Risk factors

The biggest risk factor for neurofibromatosis is a family history of the disorder. About half of people who have NF1 and NF2 inherited the disease from an affected parent. People who have NF1 and NF2 and whose relatives aren't affected are likely to have a new gene mutation.

NF1 and NF2 are both autosomal dominant disorders, meaning that any child of a parent who is affected by the disorder has a 50% chance of inheriting the genetic mutation.

The inheritance pattern for schwannomatosis is less clear. Researchers currently estimate that the risk of inheriting schwannomatosis from an affected parent is about 15%.

Autosomal dominant inheritance pattern

In an autosomal dominant disorder, the mutated gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You need only one mutated gene to be affected by this type of disorder. A person with an autosomal dominant disorder — in this case, the father — has a 50% chance of having an affected child with one mutated gene (dominant gene) and a 50% chance of having an unaffected child with two normal genes (recessive genes).

Complications

Complications of neurofibromatosis vary, even within the same family. Generally, complications result from tumors that affect nerve tissue or press on internal organs.

NF1 complications

Complications of NF1 include:

  • Neurological problems. Learning and thinking difficulties are the most common neurological problems associated with NF1. Uncommon complications include epilepsy and the buildup of excess fluid in the brain.
  • Concerns with appearance. Visible signs of neurofibromatosis — such as extensive cafe au lait spots, many neurofibromas in the facial area or large neurofibromas — can cause anxiety and emotional distress, even if they're not medically serious.
  • Skeletal problems. Some children have abnormally formed bones, which can result in bowing of the legs and fractures that sometimes don't heal. NF1 can cause curvature of the spine (scoliosis) that may need bracing or surgery. NF1 is also associated with decreased bone mineral density, which increases the risk of weak bones (osteoporosis).
  • Vision problems. Sometimes a tumor develops on the optic nerve (optic glioma), which can affect vision.
  • Problems during times of hormonal change. Hormonal changes associated with puberty or pregnancy might cause an increase in neurofibromas. Most women who have NF1 have healthy pregnancies but will likely need monitoring by an obstetrician who is familiar with the disorder.
  • Cardiovascular problems. People who have NF1 have an increased risk of high blood pressure and may develop blood vessel abnormalities.
  • Breathing problems. Rarely, plexiform neurofibromas can put pressure on the airway.
  • Cancer. An estimated 3% to 5% of people who have NF1 develop cancerous tumors. These usually arise from neurofibromas under the skin or from plexiform neurofibromas. People who have NF1 also have a higher risk of other forms of cancer, such as breast cancer, leukemia, colorectal cancer, brain tumors and some types of soft tissue cancer. Women who have NF1 should start screening for breast cancer at an earlier age than the general population.
  • Benign adrenal gland tumor (pheochromocytoma). This noncancerous tumor secretes hormones that raise your blood pressure. Surgery is usually needed to remove the pheochromocytoma.

NF2 complications

Complications of NF2 include:

  • Partial or total deafness
  • Facial nerve damage
  • Vision problems
  • Small benign skin tumors (skin schwannomas)
  • Weakness or numbness in the extremities
  • Multiple benign brain tumors or spinal tumors (meningiomas) requiring frequent surgeries

Schwannomatosis complications

The pain caused by schwannomatosis can be debilitating and may require surgical treatment or management by a pain specialist.

Diagnosis

Your doctor will start with a review of your personal and family medical history and a physical examination.

Your doctor will check your skin for cafe au lait spots, which can help diagnose NF1.

If additional tests are needed to diagnose NF1, NF2 or schwannomatosis, your doctor might recommend:

  • Eye exam. An eye doctor can detect Lisch nodules, cataracts and visual loss.
  • Hearing and balance exams. A test that measures hearing (audiometry), a test that uses electrodes to record your eye movements (electronystagmography) and a test that measures the electrical messages that carry sound from the inner ear to the brain (brainstem auditory evoked response) can help assess hearing and balance problems in people who have NF2.
  • Imaging tests. X-rays, CT scans or MRIs can help identify bone abnormalities, tumors in the brain or spinal cord, and very small tumors. An MRI might be used to diagnose optic gliomas. Imaging tests are also often used to monitor NF2 and schwannomatosis.
  • Genetic tests. Tests to identify NF1 and NF2 are available and can be done in pregnancy before a baby is born. Ask your doctor about genetic counseling. Genetic tests won't always identify schwannomatosis because other, unknown genes may be involved with the disorder. However, some women choose genetic testing for SMARCB1 and LZTR1 before having children.

For a diagnosis of NF1, you must have at least two signs of the condition. If your child has only one sign and no family history of NF1, your doctor will likely monitor your child for the development of any additional signs. A diagnosis of NF1 is usually made by age 4.

Genetic testing may help establish the diagnosis.

Treatment

There isn't a cure for neurofibromatosis, but signs and symptoms can be managed. Generally, the sooner someone is under the care of a doctor trained in treating neurofibromatosis, the better the outcome.

Monitoring

If your child has NF1, your doctor is likely to recommend yearly age-appropriate checkups to:

  • Assess your child's skin for new neurofibromas or changes in existing ones
  • Check for signs of high blood pressure
  • Evaluate your child's growth and development — including height, weight and head circumference — according to growth charts available for children who have NF1
  • Check for signs of early puberty
  • Evaluate your child for any skeletal changes and abnormalities
  • Assess your child's learning development and progress in school
  • Obtain a complete eye examination

Contact your doctor promptly if you notice any changes in signs or symptoms between visits. Many complications of NF1 can be treated effectively if therapy starts early.

Medication

Selumetinib (Koselugo) is a treatment for plexiform neurofibroma in children. Clinical trials of similar drugs are currently ongoing for children and adults.

Surgery and other procedures

Your doctor might recommend surgery or other procedures to treat severe symptoms or complications of neurofibromatosis.

  • Surgery to remove tumors. Symptoms can be relieved by removing all or part of tumors that are compressing nearby tissue or damaging organs. If you have NF2 and have experienced hearing loss, brainstem compression or tumor growth, your doctor might recommend surgery to remove acoustic neuromas that are causing you problems. Complete removal of schwannomas in people with schwannomatosis can ease pain substantially.
  • Stereotactic radiosurgery. This procedure delivers radiation precisely to your tumor and doesn't require an incision. Stereotactic radiosurgery might be an option to remove acoustic neuromas if you have NF2. Stereotactic radiosurgery can help preserve your hearing.
  • Auditory brainstem implants and cochlear implants. These devices might help improve your hearing if you have NF2 and hearing loss.

Cancer treatment

Malignant tumors and other cancers associated with neurofibromatosis are treated with standard cancer therapies, such as surgery, chemotherapy and radiation therapy. Early diagnosis and treatment are the most important factors contributing to a good outcome.

Pain medications

Managing pain is an important part of treatment for schwannomatosis. Your doctor might recommend:

  • Drugs for nerve pain such as gabapentin (Neurontin, Gralise, Horizant) or pregabalin (Lyrica)
  • Tricyclic antidepressants such as amitriptyline
  • Serotonin and norepinephrine reuptake inhibitors such as duloxetine (Cymbalta, Drizalma Sprinkle)
  • Epilepsy medications such as topiramate (Topamax, Qudexy XR, Trokendi XR) or carbamazepine (Carbatrol, Tegretol, others)

Potential future treatments

Researchers are testing gene therapies for NF1. Potential new treatments could include replacing the NF1 gene to restore the function of neurofibromin.

Coping and support

Caring for a child with a chronic condition such as neurofibromatosis can be a challenge. But many children with neurofibromatosis grow up to live healthy lives with few, if any, complications.

To help you cope:

  • Find a primary care doctor you can trust and who can coordinate your child's care with other specialists. The Children's Tumor Foundation has an online tool to help you find a neurofibromatosis specialist in your area.
  • Join a support group for parents who care for children who have neurofibromatosis, ADHD, special needs or chronic illnesses in general.
  • Accept help for daily needs such as cooking, cleaning or caring for your other children or simply to take a needed break.

Seek academic support for children who have learning disabilities.

Preparing for an appointment

You may be referred to a doctor who specializes in brain and nervous system conditions (neurologist).

It's a good idea to be well prepared for your appointment. Here's some information to help you get ready and know what to expect from your doctor.

What you can do

  • Write down a list of concerns, making a note of when you first noticed them.
  • Bring a complete medical and family history with you, if your doctor doesn't already have it.
  • Make a note of key personal information, including things like recent life changes, or major stresses.
  • Make a list of all medications, vitamins or supplements that you or your child is taking.
  • Bring photographs of any family members — living or deceased — who may have had similar signs and symptoms.
  • Write down a list of questions to ask your doctor.

Your time with your doctor is limited. Preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. For neurofibromatosis, some basic questions to ask your doctor include:

  • What type of neurofibromatosis do you suspect?
  • What tests do you recommend?
  • What treatments are available?
  • How should the condition be monitored for changes?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask other questions that occur to you.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may allow time later to cover other points you want to address. Your doctor may ask:

  • When did you first notice signs or symptoms? Have they changed over time?
  • Is there a family history of neurofibromatosis?

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