Neurofibromatosis

Definition

Neurofibromatosis is a genetic disorder that disrupts cell growth in your nervous system, causing tumors to form on nerve tissue. These tumors can occur anywhere in the nervous system, including in your brain, spinal cord, and large and small nerves. Neurofibromatosis is typically diagnosed in childhood or early adulthood.

The tumors are usually noncancerous (benign) and the disorder is usually mild. But effects of neurofibromatosis can range from hearing loss and learning impairment to cardiovascular complications and, in a few cases, cancer.

Neurofibromatosis treatment aims to maximize healthy growth and development and to manage complications as soon as they arise. In cases in which neurofibromatosis causes large tumors or tumors that are pressing on a nerve, surgery may help ease symptoms.

Symptoms

Three distinct types of neurofibromatosis exist, each with different signs and symptoms.

Neurofibromatosis 1 (NF1)
NF1 typically appears in childhood. Signs and symptoms include:

  • Flat, light-brown spots on the skin. These harmless spots, also called cafe au lait (ka-FAY oh LAY) spots, are common in many people. But if you have more than six of them, it's a strong indication of NF1. With NF1, cafe au lait spots usually are present at birth or appear during the first year of life. Their number tends to increase during early childhood and then stabilize. They aren't serious but can sometimes be a cosmetic concern.
  • Freckling in the armpits or groin area. This sign usually appears by 4 to 5 years of age.
  • Soft bumps on or under the skin (neurofibromas). These are benign tumors that grow on nerve tissue close to your skin. Sometimes, a growth will involve multiple nerves (plexiform neurofibroma).
  • Tiny bumps on the iris of your eye (Lisch nodules). It's hard to see these harmless lesions just by looking at them, but your doctor can detect them with a special instrument.
  • Bone deformities. Abnormalities in the way bones grow and a deficiency in bone mineral density can cause bone deformities such as a curved spine (scoliosis) or bowed lower leg.
  • Learning disabilities. Impaired intelligence (cognition) is common in children with NF1, but is usually mild. Most children are in the average or low-average range. Often, children with NF1 have a specific learning disability, such as problems with visual-spatial skills or attention-deficit/hyperactivity disorder (ADHD).
  • Larger than average head size. Children with NF1 tend to have a larger brain volume, but it's unknown whether this is related to cognitive impairment.
  • Short stature. Short stature is another characteristic occasionally seen in children with NF1.

Neurofibromatosis 2 (NF2)
NF2 is much less common than NF1. Signs and symptoms of NF2 usually result from the development of vestibular schwannomas (also known as acoustic neuromas) in both ears. These benign tumors grow on the nerve that carries sound and balance information from the inner ear to the brain (the eighth cranial nerve). Resulting signs and symptoms typically appear in the late teen and early adult years, and include:

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

In some cases, NF2 can lead to growths in other nerves of the body, including the cranial, spinal, visual (optic) and peripheral nerves. Associated signs and symptoms may include:

  • Cataracts
  • Numbness and weakness in the arms or legs

Schwannomatosis
Schwannomatosis is a rare form of neurofibromatosis only recently recognized. It mostly seems to affect people in their 20s and 30s. Schwannomatosis causes tumors called schwannomas to develop on cranial, spinal and peripheral nerves, but not on the nerve that carries sound and balance information from the inner ear to the brain (the eighth cranial nerve), so it doesn't cause hearing loss, making it different from NF2. As with NF2, though, schwannomatosis doesn't cause cognitive impairment. The main symptom of schwannomatosis is:

  • Chronic pain, which can occur anywhere in the body

When to see a doctor
If you notice signs or symptoms of neurofibromatosis in your child or yourself, call your doctor for an appointment or bring it up at your next visit. The tumors associated with neurofibromatosis are almost always benign and slow growing. So although it's important to obtain a timely diagnosis and monitor for complications, the situation isn't an emergency.

Causes

What causes neurofibromatosis has yet to be fully explained, but it appears to be mostly due to genetic defects (mutations) that either are passed on by a parent or occur spontaneously at conception. Each form of neurofibromatosis is caused by mutations in different genes.

Neurofibromatosis 1 (NF1)
The NF1 gene is located on chromosome 17. Normally, this gene produces a protein called neurofibromin, which is abundant in nervous system tissue and helps regulate cell growth. A mutation of the NF1 gene causes a loss of neurofibromin, which allows cells to grow uncontrolled. This results in the tumors characteristic of NF1.

Neurofibromatosis 2 (NF2)
A similar problem occurs with NF2. The NF2 gene is located on chromosome 22, which produces a protein called merlin. A mutation of the NF2 gene causes loss of merlin, which also leads to uncontrolled cell growth.

Schwannomatosis
Because schwannomatosis has only recently been identified as a separate type of neurofibromatosis, its exact cause is still under scrutiny. In a small number of familial cases, it's been associated with a mutation of the SMARCB1/INI1 gene, but in most cases the cause is unknown. The occurrence of schwannomatosis is more spontaneous (sporadic) than inherited.

Risk factors

The biggest risk factor for neurofibromatosis is a family history of the disorder. About half of NF1 and NF2 cases are inherited. The remaining cases result from spontaneous mutations that occur at conception.

NF1 and NF2 are both autosomal dominant disorders, which means that any child of a parent with the disorder has a 50 percent 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 around 15 percent.

Complications

Complications of neurofibromatosis vary, even within the same family. Generally, complications result from tumor growth distorting nerve tissue or pressing on internal organs.

It's not possible to predict how the disease will progress in any one individual but most people with neurofibromatosis experience a mild or moderate form of the disorder, regardless of type. Usually, serious complications develop prior to adolescence.

Neurofibromatosis 1 (NF1)
Common complications of NF1 include:

  • Neurological problems. Learning difficulties occur in up to 60 percent of NF1 cases and are the most common neurological problem associated with NF1. Uncommon neurological complications associated with NF1 include epilepsy, stroke and buildup of excess fluid in the brain (hydrocephalus).
  • Concerns with appearance. Visible signs of neurofibromatosis — such as extensive cafe au lait spots, nerve tumors (neurofibromas) in the facial area or large neurofibromas — can cause anxiety and emotional distress, even if not medically serious.
  • Skeletal problems. Some children have abnormally formed bones, which can result in curvature of the spine (scoliosis) and bowed legs. NF1 is also associated with decreased bone mineral density, which increases your risk of weak bones (osteoporosis).
  • Visual difficulties. Occasionally in children, a tumor growing on the nerve leading from the eye to the brain (optic nerve) can cause visual problems.
  • Increase in neurofibromas. Hormonal changes associated with puberty, pregnancy or menopause may cause an increase in neurofibromas. Most women with NF1 have healthy pregnancies but will likely need to be monitored by an obstetrician familiar with NF1, in addition to her NF1 specialist.
  • Cardiovascular problems. People with NF1 have an increased risk of high blood pressure and, rarely, blood vessel abnormalities.
  • Cancer. Less than 10 percent of people with NF1 develop cancerous (malignant) tumors. These usually arise from neurofibromas under the skin or plexiform neurofibromas involving multiple nerves. Monitor neurofibromas vigilantly for any change in appearance, size or number. Changes may indicate cancerous growth. The earlier a malignancy is detected, the better the chances for effective treatment. People with NF1 also have a higher risk of other forms of cancer, such as breast cancer, leukemia, brain tumors and some types of soft tissue cancer.

Neurofibromatosis 2 (NF2)
Expanding tumors in people with NF2 may cause:

  • Partial or total deafness
  • Facial nerve damage
  • Visual difficulties
  • Weakness or numbness in the extremities
  • Multiple benign brain 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.

Preparing for your appointment

You'll probably first discuss any concerns with your child's pediatrician or your primary care doctor. Eventually, your doctor may refer you to other specialists, depending on whether a diagnosis of neurofibromatosis is made and whether complications arise. For your first visit, which may well coincide with a routine well-child visit, it's a good idea to come prepared to make the best use of the time allotted.

What you can do

  • Write down a list of concerns, making a note of when you first started having them.
  • Bring your child's complete medical and family history with you — or your own if you're the one being evaluated — if your doctor doesn't already have it.
  • Compile a list of questions for your doctor, asking about possible causes, treatments, outcomes and next steps.
  • Take notes at the appointment to help you remember key points later on.
  • Bring photographs of other family members (living or deceased) who you think may have had similar physical findings

What to expect from your doctor
Your doctor is likely to conduct a thorough physical examination, as well as ask you to describe your concerns in detail. Your doctor may also conduct some cognitive tests. Depending on your child's age, your doctor may ask about performance in school.

Because some of the signs and symptoms of neurofibromatosis are age-dependent, it may take a while, even years perhaps, before a definitive diagnosis can be made.

Tests and diagnosis

Depending on the type of neurofibromatosis suspected, your doctor may conduct one or more of the following exams or tests:

  • Physical exam and medical history. NF1 is usually diagnosed on the basis of a thorough physical exam, checking for the characteristics typical of NF1. Your doctor may use a special lamp to check your skin for light-colored cafe au lait spots. A physical exam is also important for an NF2 diagnosis. A family history of NF1 or NF2 can help confirm either diagnosis.
  • Eye exam. Examination by an eye doctor (ophthalmologist) can detect tiny bumps on the iris of your eye (Lisch nodules) and cataracts.
  • Ear exam. Hearing and balance tests such as audiometry, electronystagmography and brainstem auditory evoked response can help determine the level of hearing and balance function in a person with NF2.
  • Imaging tests. Imaging tests, such as X-rays, CT scans and MRIs, aren't always required, but they can help identify bone abnormalities, deep tumors in the brain or spinal cord, and very small tumors. This may be particularly helpful with NF2 and schwannomatosis.
  • Genetic tests. Genetic tests are available for NF1, NF2 and schwannomatosis, and may be done prenatally.

Treatment and drugs

The mainstay of treatment for neurofibromatosis is monitoring for complications, often by a team of specialists at a neurofibromatosis clinic, and beginning appropriate treatment as early as possible. Generally, the sooner you or your child are under the care of a doctor who specializes in neurofibromatosis, the better the outcome.

Monitoring
If you have a child with NF1, your doctor is likely to recommend yearly age-appropriate checkups to:

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

If you notice any changes in signs or symptoms between visits, such as rapid growth of a neurofibroma or onset of pain in a tumor, it's important to contact your doctor promptly to rule out the possibility of a cancerous tumor and to access appropriate treatment at an early stage.

Once a child with NF1 reaches adulthood, the frequency of monitoring can be adjusted to suit the needs of the person with NF1. Adults with mild disease may not need monitoring as often as someone with more severe complications.

Surgery and other procedures

  • Surgery to remove all or part of tumors that are compressing nearby tissues or damaging organs may help relieve symptoms. This is true for all forms of neurofibromatosis. Complete removal of schwannomas in schwannomatosis can ease pain substantially. However, be sure to discuss the pros and cons of surgery carefully with a doctor or surgeon experienced in treating nerve tumors. For example, tumors often grow back and operating on the same site again may not be as feasible as it was the first time around. Also, surgery to remove a vestibular schwannoma may carry a risk of total hearing loss or damage to facial nerves.
  • Stereotactic radiosurgery may be an option for those with NF2 and a vestibular schwannoma. This procedure allows your doctor to deliver radiation very precisely to the location of the tumor and it can help preserve hearing to an extent. But it may create a concern of radiation-induced cancer, especially if the radiation is applied repetitively and at a young age.
  • Plastic surgery and laser therapy may be used to remove lesions on the surface of the skin and to help improve appearance.
  • A back brace is often used to treat scoliosis. In severe cases, back surgery may also be an option.

Cancer treatment
Malignant tumors and other cancers associated with neurofibromatosis (more often NF1) are treated with standard cancer therapies, such as surgery, chemotherapy and radiation therapy.

Coping and support

Caring for a child with a chronic illness such as neurofibromatosis can be a challenge, even if the illness is mild. Greater severity of symptoms can make it even harder. There are a lot of medical appointments to keep, treatments to track, instructions to follow — all of this, in addition to general concern about your child's health and anxiety over outcomes, can be overwhelming. It may help to keep in mind that many children with neurofibromatosis grow up to live healthy lives with few, if any, complications.

Perhaps the most important thing you can do for your child's sake and yourself is to find a primary care doctor you 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.

You may also find it helpful to join a support group for parents who care for children with neurofibromatosis, ADHD, special needs or chronic illnesses in general. The Children's Tumor Foundation lists support groups and family events by state on its website. You can also check your local community listings for support groups or ask your doctor for information.

Extended family and friends can be your biggest and closest support network. Don't be afraid to accept their help with daily needs, such as cooking, cleaning, caring for your other children or simply giving you a needed break. Allowing them to share your journey, even in small ways, can enrich their lives as well as yours.

Our Services

Healthcare Expert Shanghai