Neurofibromatosis is a multisystem genetic disorder in which benign (noncancerous) tumors grow on and around nerves, causing a wide range of signs and symptoms that may be apparent at birth, but more often develop during adolescence and young adulthood. The signs and symptoms can vary widely among people.

According to the March of Dimes, neurofibromatosis is one of the most common genetic disorders. The National Institutes of Health (NIH) estimates that it affects 100,000 people in the United States.

There are three specific types of neurofibromatosis: NF1, NF2 and schwannomatosis. Of the three types, NF1 is the most common. In most cases NF1 causes mild symptoms, which may include six or more tan spots on the skin, freckles under the arms or in the groin, or small tan or brown spots in the iris of the eyes. However, tumors can grow on the skin or within the body, and can interfere with major organs. Learning disabilities, scoliosis, seizures and other conditions are more common in people with NF1.

NF2 causes symptoms such as deafness and problems with balance, because tumors grow on the auditory nerve (the nerve that transmits signals from the ear to the brain). Schwannomatosis, once considered to be a type of NF2, is characterized by tumors on nerves in the peripheral nervous system that can cause chronic severe pain. The symptoms of neurofibromatosis vary widely from one patient to another.

The disorders may be inherited from parents or may occur as spontaneous mutations. Neurofibromatoses are autosomal dominant genetic disorders, meaning that a parent with the genetic mutation has a 50 percent chance of passing the mutation to any children. However, spontaneous genetic changes cause approximately 30 percent to 50 percent of neurofibromatosis cases according to the NIH.

Treatment of the different types of neurofibromatosis may involve surgery. Depending on the location, some tumors can be removed surgically, although tumor reoccurrence is possible. There is no cure for the genetic mutations that damage nerves. Some symptoms such as seizures or severe pain may be treated with medications.

Genetic tests to identify NF1 are available and may be performed before pregnancy in people with a family history of the disease. Prenatal testing using amniocentesis or chorionic villi sampling is also available for NF1. Genetic tests for NF2 have limited accuracy. No genetic tests are available to identify schwannomatosis.