About Neurofibromatosis
What is neurofibromatosis?
Neurofibromatoses are genetic disorders of the nervous system that primarily affect the development and growth of neural (nerve) cell tissues. These disorders cause tumors to grow on nerves and produce other abnormalities such as skin changes and bone deformities.
Although many affected persons inherit the disorder, between 30 and 50 percent of new cases arise spontaneously through mutation (change) in an individual’s genes. Once this change has taken place, the mutant gene can be passed on to succeeding generations.
Neurofibromatosis Type 1 (NF1) is the more common type of the neurofibromatoses. In diagnosing NF1, a physician looks for changes in skin appearance, tumors, or bone abnormalities, and/or a parent, sibling, or child with NF1. Symptoms of NF1, particularly those on the skin, are often evident at birth or during infancy and almost always by the time a child is about 10 years old.
Is there any treatment?
Treatment for NF1 is presently aimed at controlling symptoms. Surgery can help some NF1 bone malformations and remove painful or disfiguring tumors; however, there is a chance that the tumors may grow back and in greater numbers.
In the rare instances when tumors become malignant (3 to 5 percent of all cases), treatment may include surgery, radiation or chemotherapy. Genetic testing is available for families with documented cases of NF1.
What research is being done?
Several years ago, research teams located the exact position of the NF1 gene on chromosome 17. The product of the NF1 gene is a large and complex protein called neurofibromin. One portion of this protein is similar to a family of proteins called GAP (guanosine triphosphatase-activating protein).
Scientists have demonstrated that GAP proteins play a significant role in tumor suppression in certain cancers. The similarity of the NF1 protein to GAP proteins suggests that the NF1 protein may have a similar switching role in the development of neurofibromas. Scientists theorize that defects in the gene may lessen or inhibit the normal output of its protein and allow the irregular cell growth that may lead to tumor development.
Diagnostic criteria for NF-1
Two or more of the following:
- Six or more café-au-lait spots 1.5 cm or larger in post-pubertal individuals, 0.5 cm or larger in pre-pubertal individuals
- Two or more neurofibromas of any type or one or more plexiform neurofibroma
- Freckling in the axilla or groin
- Optic glioma (tumor of the optic pathway)
- Two or more Lisch nodules (benign iris hamartomas)
- A distinctive bony lesion: dysplasia of the sphenoid bone or dysplasia or thinning of long bone cortex
- A first-degree relative with NF1
Read more about neurofibromatosis type 1.