Neurofibromatosis is a genetic disorder that causes tumors to form on nerve tissue. These tumors can develop anywhere in your nervous system, including your brain, spinal cord and nerves. Neurofibromatosis is usually diagnosed in childhood or early adulthood.
The tumors 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 affected with the disorder and 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.
Types & Symptoms
There are three types of neurofibromatosis, each with different signs and symptoms.
Neurofibromatosis 1 (NF1) usually appears in 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 (café au lait spots). These harmless spots are common in many people. Having more than six café au lait spots is a strong indication of NF1. They are usually present at birth or appear during the first years of life. After early childhood, new spots stop appearing.
- Freckling in the armpits or groin area. Freckling usually appears by ages 3 to 5. Freckles are smaller than café au lait spots and tend to occur in clusters of 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 multiple nerves (plexiform neurofibroma) Plexiform neurofibromas, when located on the face, can cause disfigurement. Neurofibromas may increase with age.
- Bone deformities. Abnormal bone growth and a deficiency in bone mineral density can cause bone deformities such as a curved spine (scoliosis) or 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 skill are common in children with NF1 but are usually mild. Often there is a specific learning disability, such as problem with reading or mathematics. Attention-deficit/hyperactivity disorder (ADHD) also is 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 with NF1 often are below average in height.
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 in 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
Sometimes NF2 can lead to the growth of schwannomas in other nerves of the body, including the cranial, spinal, visual (optic) and peripheral nerves. Signs and symptoms of these schwannomas can include:
- Numbness and weakness in the arms and legs
- Balance difficulties
- Facial drop
- Vision problems or the development of cataracts
This rare type of neurofibromatosis usually affects people after age 20. On average, symptoms 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. Because tumors don’t usually grow on both hearing nerves, Schwannomatosis doesn’t cause the hearing loss experienced by people with NF2.
Symptoms of schwannomatosis include:
- Chronic pain, which can occur anywhere in your body and can be disabling
- Numbness or weakness in various parts of your body
- Loss of muscle
When to see a doctor
See your doctor if you or your child develops signs or symptoms of neurofibromatosis. The tumors associated with neurofibromatosis are often benign and slow growing. So although it’s important to obtain a timely diagnosis, the situation isn’t an emergency.
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.
The biggest risk factor for neurofibromatosis is a family history of the disorder. About half of people with NF1 and NF2 inherited the disease from the affected parent. People with NF1 and NF2 that don’t have affected relatives likely have a new gene mutation.
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 about 15 percent.
Complications of neurofibromatosis vary, even within the same family. Generally, complications result from tumor growth distorting nerve tissue or pressing on internal organs.
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 café 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 in children 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 with NF1 have healthy pregnancies but will likely need monitoring by an obstetrician familiar with the disorder.
- Cardiovascular problems. People with NF1 have an increased risk of high blood pressure and may develop blood vessel abnormalities.
- Breathing problems. People with NF1 have an increased risk of high blood pressure and may develop blood vessel abnormalities.
- Breathing problems. Rarely, plexiform neurofibromas can pressure on the airway.
- Cancer. An estimated 3 to 5 percent of people with NF1 develop cancerous tumors. These usually arise from neurofibromas under the skin or from plexiform neurofibromas. People with 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 with NF1 should start screening for breast cancer at an earlier age than the general population.
- Benign adrenal gland tumor (pheochromocytoma). This noncancerous tumor secrete hormones that raise your blood pressure. Surgery is usually needed to remove the pheochromocytoma.
Complications on 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
The pain caused by schwannomatosis can be debilitating and may require surgical treatment or management by a pain specialist.
Your doctor will start with a review of your personal and family medical history and a physical examination.
Your doctor may use a special lamp to check your skin for café 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 and cataracts.
- 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 with NF2.
- Imaging test. 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 prenatally. 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.
Neurofibromatosis can’t be cured, but treatments can help manage signs and symptoms. Generally, the sooner you or your child is under the care of a doctor trained in treating neurofibromatosis, the better the outcome.
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 with 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. It’s important to rule out the possibility of a cancerous tumor and receive appropriate treatment at an early stage.
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.
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.
Managing pain is an important part of treatment of 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)
- Epilepsy medications such as topiramate (Topamax, Query 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 with 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 with learning disabilities.