Neurofibromatosis (NF) is a genetic disease that causes tumors to develop in the nervous system. There are three types of neurofibromatosis that are each associated with unique signs and symptoms:
Neurofibromatosis type 1 (NF1) causes skin changes (cafe-au-lait spots, freckling in armpit and groin area); bone abnormalities; optic gliomas; and tumors on the nerve tissue or under the skin. Signs and symptoms are usually present at birth.
Neurofibromatosis type 2 (NF2) causes acoustic neuromas; hearing loss; ringing in the ears; poor balance; brain and/or spinal tumors; and cataracts at a young age. It often starts in the teen years.
Schwannomatosis causes schwannomas, pain, numbness, and weakness. It is the rarest type.
All three types of NF are inherited in an autosomal dominant manner. There is no cure for NF. Treatment is aimed at controlling symptoms and may include surgery to remove tumors, radiation therapy, and/or medicines.
Neurofibromatosis is inherited in an autosomal dominant manner. This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family. A person with neurofibromatosis has a 50% chance with each pregnancy of passing along the altered gene to his or her child.
Neurofibromatosis type 1 is a condition characterized by changes in skin coloring (pigmentation) and the growth of tumors along nerves in the skin, brain, and other parts of the body. The signs and symptoms of this condition vary widely among affected people.
Beginning in early childhood, almost all people with neurofibromatosis type 1 have multiple café-au-lait spots, which are flat patches on the skin that are darker than the surrounding area. These spots increase in size and number as the individual grows older. Freckles in the underarms and groin typically develop later in childhood.
Most adults with neurofibromatosis type 1 develop neurofibromas, which are noncancerous (benign) tumors that are usually located on or just under the skin. These tumors may also occur in nerves near the spinal cord or along nerves elsewhere in the body. Some people with neurofibromatosis type 1 develop cancerous tumors that grow along nerves. These tumors, which usually develop in adolescence or adulthood, are called malignant peripheral nerve sheath tumors. People with neurofibromatosis type 1 also have an increased risk of developing other cancers, including brain tumors and cancer of blood-forming tissue (leukemia).
During childhood, benign growths called Lisch nodules often appear in the colored part of the eye(the iris). Lisch nodules do not interfere with vision. Some affected individuals also develop tumors that grow along the nerve leading from the eye to the brain (the optic nerve). These tumors, which are called optic gliomas, may lead to reduced vision or total vision loss. In some cases, optic gliomas have no effect on vision.
Additional signs and symptoms of neurofibromatosis type 1 include high blood pressure (hypertension), short stature, an unusually large head (macrocephaly), and skeletal abnormalities such as an abnormal curvature of the spine (scoliosis). Although most people with neurofibromatosis type 1 have normal intelligence, learning disabilities and attention deficit hyperactivity disorder (ADHD) occur frequently in affected individuals.