A disease caused by a genetic mutation. People with neurofibromatosis usually have many pigmented spots and bumps in their skin. The bumps are non-cancerous growths on the nerves. They can cause pain, tingling or numbness, bone deformities and seizures. In rare cases, tumors grow in the head. There is an increased risk of cancer. The cause can’t be treated. The symptoms can be relieved with medication. Bothersome, painful or potentially cancerous growths are removed surgically.