What is Neurofibromatosis (NF)?

There are two main types of neurofibromatosis: NF1 and NF2. However, they are very different conditions caused by different gene mutations, and they appear with very different sets of symptoms and levels of severity. A third condition that can occur with nerve tumors, called schwannomatosis, is rare and has its own range of potential manifestations.

Neurofibromatosis 1 (NF1), also sometimes called von Recklinghausen's disease, is the most common. The vast majority of patients seen at the NF Center have NF1, given that it is much more common than NF2 or schwannomatosis. About half of NF1 patients inherit their disorder from a parent. For the other half of patients, the disease is the result of spontaneous genetic change in the NF1 gene, which is located on chromosome 17.

Symptoms of NF1 vary a lot, even among family members who share the condition. Many people present only some of the signs and symptoms. It’s very hard to predict how someone’s clinical NF1 symptoms are going to unfold based on the experience of his or her parents or other affected family members.

Neurofibromatosis Type 1 Symptoms

  • Light brown (café au lait) skin spots
  • Neurofibromas (nonmalignant nerve tumors that typically develop after childhood and increase in number over time)
  • Freckles under the armpits or around the groin
  • Tiny bumps on the iris of the eyes, called Lisch nodules
  • Tumors along the optic nerve of the eye, called optic glioma
  • Scoliosis, or curvature of the spine
  • Bowing of the lower leg (tibia or fibula) that fractures and then does not heal (pseudarthrosis)
  • Other tumors
  • Learning difficulties

Neurofibromatosis type 2 (NF2) is much less common than NF1 and has very different symptoms. NF2 is caused by a mutation in the merlin gene.

Neurofibromatosis Type 2 Symptoms

  • Schwannomas (tumors that grow on the covering of nerves) of the cranial and peripheral nerves. The hallmark of NF2 is schwannoma on the vestibular nerve, which runs from the inner ear to the brain.
  • Hearing loss

Schwannomatosis is even less common than NF2. Symptoms usually arise in early adulthood, but sometimes they appear in late childhood or adolescence.

Schwannomatosis Symptoms

  • Schwannomas, as in NF2, but rarely on the vestibular nerves
  • Numbness
  • Weakness
  • Tingling
  • Headaches
  • Chronic pain, which can affect any part of the body