Neurofibromatosis

Neurofibromatosis is a complicated genetic disease that can affect both men and women in all races and ethnic groups. The neurofibromatoses are a set of genetic disorders (Read about "Genetics") that cause tumors to grow on and along various types of nerves. The tumors can grow anywhere on or in the body. The disease can also affect non-nervous tissues like bones and skin and lead to developmental abnormalities such as learning disorders, according to the National Neurofibromatosis Foundation (NNFF).

Scientists have classified Neurofibromatosis (NF) into two distinct types:

• NF1
• NF2

Both forms are genetic disorders that may be inherited from a parent, but according to the National Institute of Neurological Disorders and Stroke (NINDS), 30 to 50 percent of the cases are the result of a gene mutation in an individual rather than being inherited.

Neurofibromatosis Type 1 (NF1)

This is the more common type of the neurofibromatoses, occurring in 1 in 4,000 births. It is sometimes called Von Recklinghausen NF or Peripheral NF. In most cases, symptoms of NF1 are mild, and patients live normal and productive lives. In some cases, however, NF1 can be severely debilitating.

It is mainly characterized by multiple light brown spots (called café-au-lait spots) and neurofibromas (nerve tumors) on or under the skin. It can also cause bone defects and curvature of the spine (scoliosis). (Read about "Skeletal System" "Curvature of the Spine") Occasionally, tumors develop in the brain (Read about "Brain Tumors"), on cranial nerves or on the spinal cord. (Read about "Nervous System") About half of the people with NF also have learning disabilities, according to NNFF.

Symptoms

Signs of NF1, especially those on the skin, are often evident at birth or soon after and almost always by the time a child is about ten years old, according to NINDS. People with NF usually have six or more café-au-lait spots, varying in size from 1/4 inch in children and 3/4 of an inch in adults to several inches in diameter or larger. They may also have freckling in the armpit or groin area.

Another common symptom is the development of neurofibromas or nerve tumors. These benign growths usually develop on or just underneath the skin (called dermal fibromas), but can also occur deeper in the body (called plexiform fibromas). They normally become evident at around 10 to 15 years of age, according to NINDS.

Iris nevi may also appear around puberty. These are clumps of pigment in the colored part of the eye. (Read about "The Eye") They are sometimes called Lisch nodules. They do not affect vision or cause medical problems, but can be helpful in confirming a diagnosis of NF.

Diagnosis

In diagnosing NF1, a doctor will look for two or more of the following, according to NNFF:

• six or more café-au-lait spots (before puberty they will be over a quarter inch, after puberty over three-quarters of an inch.)
• two or more pea-sized bumps on the skin (dermal neurofibromas)
• large swollen areas on the skin (indicating plexiform neurofibromas)
• freckling in the armpits or groin areas
• pigmented bumps on the iris of the eye (Lisch nodules)
• deformation or enlargement of the bones or curvature of the spine (scoliosis)
• tumor on the optic nerve (optic glioma)
• family history of NF1 (Read about "Family Health History")

Lab tests (Read about "Laboratory Testing") are now available in most cases to determine whether a person has NF, according to NNFF. Genetic testing is available for families with documented cases of NF1 and NF2 and direct gene testing is currently available for NF1. Also, prenatal diagnosis of familial NF1 or NF2 is also possible utilizing amniocentesis or chorionic villus sampling procedures. (Read about "Pregnancy Testing") If you have questions about being tested for NF, you can talk to your doctor.

Because NF1 is such a variable disease, there is no way to tell who will have a mild case and who will develop serious complications. The disorder varies even within families. The majority (60 percent) of people with NF has mild forms, another 20 percent have correctable problems and another 20 percent have serious problems.

Treatment

There is no cure for NF. Present treatments are aimed at controlling the symptoms of the disease. Surgery can remove painful or disfiguring tumors (Read about "Neurosurgery"); however, there is a chance that the tumors may grow back and in greater numbers, according to NINDS. In the rare instances, when tumors become malignant (3 to 5 percent of all cases), treatment may include surgery, radiation or chemotherapy. (Read about "Radiation Therapy")

Surgery can also help some bone malformations or severe scoliosis. Typically, scoliosis is mild in NF1 patients, but a child diagnosed with it should have periodic exams and x-rays of the spine. (Read about "X-rays" "The Spine") In some cases, a back brace can help prevent progression of the problem.

If a tumor forms on the optic nerve (optic glioma), which is not common, treatment would normally include surgery and radiation.

Genetics of NF1

Neurofibromatosis is the result of a single dominant gene. It may be inherited from a parent (about 50 percent of cases) or occur through a sudden gene change called spontaneous mutation (the other 50 percent). NF can appear in any family. Once a person has the NF gene, whether by inheritance or mutation, he or she has a 50 percent chance of passing it on to each of his or her children. If a child inherits the gene from a parent, it will be same type of NF. For example, a parent with NF1 would pass on the gene for NF1. If a parent has NF2, the child would inherit NF2.

Living with NF1

Most cases of NF1 are mild and people with it are able to lead normal lives. For those with more serious symptoms, it can be more of a struggle. In any case, a person with NF should see a physician regularly and may want to choose a doctor who is familiar with NF.

Children with NF should have their growth and development monitored much like any other child with regular check-ups. (Read about "Child Development") However, doctors should also check for evidence of scoliosis, signs of learning disabilities and examine the skin for any café-au-lait spots or neurofibromas.

If certain symptoms or medical problems develop, people with NF1 may require specific tests or need to see specialists, such as ophthalmologists, plastic surgeons, etc. (Read about "Plastic Surgery")

NF cannot only cause physical problems, but emotional ones. Some patients suffer stress, anxiety or feelings of loneliness and isolation. (Read about "Stress" "Depressive Illnesses" "Anxiety") Therapists and counselors may help, and there are many support groups for those with NF.

Neurofibromatosis Type 2 (NF2)

This form of the neurofibromatosis is much rarer, occurring in 1 in 40,000 births. It is also know as Bilateral Acoustic NF (BAN). It is characterized by multiple tumors on the cranial and spinal nerves and by other lesions of the brain and spinal cord (Read about "The Brain" "Nervous System"), according to the NNFF. The primary characteristic is bilateral (occurring on both sides of the body) tumors of the eighth cranial nerve. These are the auditory nerves, affecting the hearing. (Read about "The Ear and Hearing") Thus, hearing loss beginning in the teens or early twenties is generally the first sign of the disease. (Read about "Hearing Loss")

People with NF2 are also at high risk for developing brain tumors and in severe cases, the disease can be life threatening. (Read about "Brain Tumors")

Symptoms

As mentioned, early hearing loss is a primary symptom of NF2. Those with the disease might also suffer tinnitus (ringing in the ears) and poor balance. (Read about "Tinnitus" "Balance Disorders")

Although tumors of the eighth cranial nerve are most common, people with NF2 may develop tumors of other nearby nerves as well. Because of the proximity to vital cranial nerves and the brain stem, NINDS says NF2 can be life threatening.

Other symptoms of NF2 may include headache, facial pain or numbness, a change in vision, or a lump under the skin from development of a neurofibroma.

Diagnosis

In diagnosing NF2, a doctor will look for the following, according to NINDS:

• bilateral eighth nerve tumors
• family history of NF2 and a unilateral (occurring on one side of the body) eighth nerve tumor (Read about "Family Health History")
• family history of NF2 and any two of the following: neurofibroma, schwannoma (type of tumor that develops in the wrapping around the nerves), meningioma (type of spinal tumor), glioma (type of nervous tissue tumor) or cataract (Read about "Cataracts") at an early age

There is no way to tell how many tumors a person with NF2 will develop or where they might grow. However, MRI (magnetic resonance imaging) scans can help track the progression of tumors, and repeated scans over time can tell if a tumor is static or growing. (Read about "MRI - Magnetic Resonance Imaging") Audiometry, or hearing, tests can help track the progression of eighth cranial nerve tumors.

Treatment

Again, there is no cure for NF. The present treatments are aimed at controlling symptoms. For the tumors of NF2, the only treatments are surgery and radiation therapy. (Read about "Radiation Therapy") Most people with NF2 will require at least one operation in their lifetime, according to the NNFF. But surgery carries risk because NF2 tumors are in delicate areas, on nerves and/or near the brain and spinal cord. Surgery in these areas can sometimes cause further injury, so the risks should be weighed carefully. (Read about "Neurosurgery")

When surgery is not an option, radiation therapy may be considered. But again, it carries risk and should be carefully considered. You can discuss your options with your doctor.

Genetics of NF2

As with NF1, NF2 is the result of a single dominant gene. Half of the time it is inherited from a parent, the other half occurs through spontaneous genetic mutation. Once a person has the NF gene, whether by inheritance or mutation, he or she has a 50 percent chance of passing it on to each of his or her children.

Living with NF2

Those living with NF2 should see a physician regularly and may want to see one who is familiar with the disease. They may even want to seek out a specialist, such as a neurologist.

Diminished or loss of hearing affects nearly everyone with NF2, as about 90 percent of those with the disease develop the bilateral eighth cranial nerve tumors affecting hearing. Regular hearing tests can help track the progression of these tumors.

Those with NF2 can suffer the same stress (Read about "Stress") and emotional problems as people with NF1. Counseling and support groups may be helpful in dealing with these issues.

Related Information:

    Hearing/Speech/Smell/Taste Glossary