Neurofibromatosis (NF) is a group of genetic disorders that cause tumors to form on nerve tissue. There are three types of neurofibromatosis: NF1, NF2, and schwannomatosis.
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NF1: This is the most common type of neurofibromatosis. It is usually diagnosed during childhood and signs are often noticeable at birth or shortly afterward and almost always by age 10. Signs and symptoms include flat, light brown spots on the skin (cafe au lait spots), tumors on or under the skin, learning disabilities, and larger than average head size.
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NF2: This type of neurofibromatosis is less common than NF1. Signs and symptoms of NF2 result from the development of tumors on the nerves inside the skull and spine. Common symptoms include problems with hearing, balance, and control of facial muscles.
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Schwannomatosis: This is a rare type of neurofibromatosis that usually affects people after age 20. Symptoms usually appear between ages 25 and 30. Schwannomatosis causes tumors to grow on nerves throughout the body, but not on the vestibular nerve, which is responsible for hearing and balance.
Neurofibromatosis is caused by mutations in genes that lead to increased risk of developing tumors. Although many people with NF inherit the gene that causes the condition, between 30 and 50 percent of cases arise from a spontaneous genetic mutation in the NF1 or NF2 gene.
Symptoms of neurofibromatosis can vary in severity and can include changes in skin coloring, the growth of tumors along nerves in the body, learning disabilities, and problems with hearing, balance, and control of facial muscles.
