Neurofibromatosis (NF) is a genetic condition causing benign tumors (neurofibromas) to grow along certain types of nerves and, in addition, it can affect the development of bones or skin. There are several variants of the disease but type 1 and type 2 NF account for the vast majority of cases.

The disease manifestations can vary from very mild to severe. Major symptoms include growths on and under the skin; skin pigmentations called café au lait spots in type 1; acoustic nerve tumors and consequent hearing loss in type 2. Growths can affect nearly all parts of the body, and pressure on nearby structures can cause a wide variety of complications. There is a small risk that the tumors transform into malignant cancerous lesions.

NF is one of the most common single-gene human diseases; around 1 in 2,500-4,000 live births are affected by NF-1, whereas NF-2 occurs in about 1 in 50,000-120,000. Both type 1 and 2 are autosomal dominant conditions, meaning that only one copy of the mutated gene need be inherited to pass the disorder. A child of a parent with neurofibromatosis and an unaffected parent will have a 50% chance of inheriting the disorder. The gene responsible for NF-1 and possibly NF-2 is thought to function as a tumor suppressor gene.

In most cases of neurofibromatosis 1, patients can live normal and productive lives. In about 25-40% of patients there is an associated learning disability with or without ADHD. In some cases of neurofibromatosis 2, the damage to nearby vital structures, such as the cranial nerves and the brainstem, can be life-threatening. When tumors are causing pain or disfiguration, surgery is thus far the only proven beneficial treatment option.