Neurofibromatosis (NF) is a group of three conditions in which tumors grow in the nervous system. The three types are neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis. In NF1 symptoms include light brown spots on the skin, freckles in the armpit and groin, small bumps within nerves, and scoliosis. In NF2 there may be hearing loss, cataracts at a young age, balance problems, flesh colored skin flaps, and muscle wasting. The tumors are generally non cancerous.
The cause is a genetic mutation in certain genes. In half of cases these are inherited from a person’s parents while in the rest they occur during early development. The tumors involve supporting cells in the nervous system rather than the neurons. In NF1 the tumors are neurofibromas (tumors of the peripheral nerves) while in NF2 and schwannomatosis tumors of Schwann cells are more common. Diagnosis is typically based on the signs and symptoms and occasionally supported by genetic testing.
There is no known prevention or cure. Surgery may be done to remove tumors that are causing problems or have become cancerous. Radiation and chemotherapy may also be used if cancer occurs. A cochlear implant or auditory brainstem implant may help some who have hearing loss.
In the United States about 1 in 3,500 people have NF1 and 1 in 25,000 have NF2. Males and females are affected equally frequently. In NF1 symptom are often present at birth and otherwise develop before 10 years of age. While the condition typically worsens with time most people with NF1 have a normal life expectancy. In NF2 symptoms may not become apparent until early adulthood. NF2 increases the risk of early death. Descriptions of the condition occur as far back as the 1st century.