What is Neurofibromatosis 1?
NF1 is the most common type of the neurofibromatoses, occurring in about 1 in 3,000 individuals. 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. Previously, NF1 was known as peripheral neurofibromatosis (or von Recklinghausen’s neurofibromatosis) because some of the symptoms–skin spots and tumors–seemed to be limited to the outer nerves, or peripheral nervous system, of the affected person. This name is no longer technically accurate because central nervous system tumors are now known to occur in NF1.
In diagnosing NF1, a physician looks for two or more of the following:
- Five or more light brown skin spots (cafe-au-lait macules) measuring more than 5 millimeters in diameter on patients prior to puberty or more than 15 millimeters across on adults and children who have reached puberty;
- Two or more neurofibromas (tumors that grow on a nerve or nerve tissue, under the skin) or one plexiform neurofibroma (involving many nerves);
- Freckling in the armpit or groin areas;
- Benign growths on the iris of the eye (known as Lisch nodules or iris hamartomas);
- A tumor on the optic nerve (optic glioma);
- Severe scoliosis (curvature of the spine);
- Enlargement or deformation of certain bones other than the spine;
- A parent, sibling, or child with NF1.
When do symptoms appear?
Symptoms, 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. Neurofibromas become evident around 10 to 15 years of age. In most cases, symptoms are mild and patients live normal and productive lives. In some cases, however, NF1 can be severely debilitating. Symptoms and severity of the disorder may vary among members of affected families.
How is NF1 treated?
Treatments are presently aimed at controlling symptoms. Surgery can help some bone malformations. For scoliosis, bone surgery may be combined with back braces. Surgery can also remove painful or disfiguring tumors. There is a chance, however, 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.