Neurofibromatosis, also known as NF, is a genetic disorder that affects 1 in every 3,000 people. There are three types of NF: NF1, NF2, and schwannomatosis. Neurofibromatosis type 1 (NF1), formerly known as von Recklinghausen NF or Peripheral NF, is the most common of the three types of neurofibromatosis, and is also one of the most common inherited neurological disorders, affecting about 1 in 3,000 people throughout the world. The disorder is characterized by multiple café au lait (light brown) skin spots and neurofibromas (small benign growths) on or under the skin, and/or freckling in the armpits or groin. About 50% of people with NF1 also have learning challenges. Softening and curving of bones, and curvature of the spine (scoliosis) may occur in some patients with NF1. Occasionally, tumors may develop in the brain, on cranial nerves, or on the spinal cord. While NF tumors are generally not cancerous, they may cause health problems by pressing on nearby body tissue. Sometimes a benign tumor may become malignant (cancerous), but most people with NF1 will never develop a malignant tumor. NF1 is usually diagnosed in childhood.