The neurofibromatoses are genetic disorders that cause tumors to grow in the nervous system and produce other problems such as skin changes and bone deformities. Many people inherit the disorder but between 30 and 50% have no family history of the disorder. This is called a “de novo” mutation. Once the mutation has occurred, it can be passed to future generations.
There are 3 types of neurofibromatosis.
Neurofibromatosis Type 1 (NF 1)
Symptoms of this may be present at birth and are always seen by age 10 years
- Light brown spots on the skin (café au lait spots)
- Two or more growths on the iris of the eye
- Tumors on the optic nerve
- A larger than normal head size
- Abnormal development of the spine, a skull bone, or the tibia
Neurofibromatosis Type 2 (NF 2)
is less common and is characterized by slow growing tumors on the eighth cranial nerve. (The cranial nerves are 12 pairs of nerves coming off the bottom of the brain.) In addition to the tumors a person with NF 2 may have cataracts at an early age, changes in the retina, and other nervous system tumors.
Schwannomatosis
is the third type of neurofibromatosis. This is characterized by the development of multiple schwannomas (a certain cell type of tumor) throughout the body except on a certain part of the eighth cranial nerve. The predominant symptom of these tumors is pain, numbness, tingling, or weakness caused by pressure on adjacent tissues.
Surgery may be recommended to remove the tumors of all types of NF. Some tumors in NF 1 can become cancerous, if so, a combination of surgery, radiation, and chemotherapy may be required. Some of the bone problems of NF 1 can be corrected surgically. Intervention for tumors of NF 2 can also be an option but may result in hearing loss. Intervention for cataracts and retinal abnormalities can also be performed. Surgical removal of schwannomas may also be recommended for pain control.
Genetic tests exist for NF 1 and NF 2 but not for schwannomatosis.