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 2 (NF2) is much less common than NF1 and has very different symptoms. NF2 is caused by a mutation in the merlin gene.
Schwannomatosis is even less common than NF2. Symptoms usually arise in early adulthood, but sometimes they appear in late childhood or adolescence.