NF has been classified into three distinct types; NF1, NF2 and Schwannomatosis. They are caused by different genes, located on different chromosomes

NF1 is not a rare disorder, it is the most common neurological disorder caused by a single gene

NF1 is the more common form of NF, occurring in 1 in 3,000 to 4,000 people worldwide (see footnotes 1 & 2 below)

NF2 is a rarer type, occurring in about 1:35-40,000 people worldwide

Although there have been few large studies, studies indicate that Schwannomatosis likely occurs in about 1:40,000 people, similar to NF2

All forms of NF are autosomal dominant genetic disorders which can be inherited from a parent who has NF or may be the result of a new or "spontaneous mutation" (change) in the sperm or egg cell

Each child of an affected parent has a 50% chance of inheriting the gene and developing NF; the type of NF inherited by the child is always the same as that of the affected parent, although the severity of the manifestations may differ from person to person within a family

NF is worldwide in distribution and affects both sexes equally and has no particular racial, geographic or ethnic distribution; therefore, NF can appear in any family

Common features of NF1 include cafe-au-lait spots, freckling, neurofibromas in or under the skin and Lisch nodules on the iris of the eye.  Most cases of NF1 are mild to moderate although some people with NF1 can develop complications like skeletal abnormalities, plexiform neurofibromas and optic gliomas.

NF1 also has a connection to developmental problems, especially learning disabilities, which are five times more common in the NF1 population than in the general population

The distinguishing feature of NF2 is tumours that grow on the eighth cranial nerve in both ears, commonly causing deafness and severe balance problems

NF2 brings on increased risk of other types of nervous system tumours as well

NF2 can also cause severe vision problems, including cataracts, retinal abnormalities and orbital tumours