Neurofibromatosis

Genetic nervous system disorder

Neurofibromatosis is a genetic nervous system disorder that causes tumors to grow around nerves. There are three types of neurofibromatosis: type 1 (NF1), type 2 (NF2), and schwannomatosis. An estimated 100,000 Americans have a form of neurofibromatosis. Neurofibromatosis occurs in both males and females of all ethnic backgrounds.

Neurofibromatosis may either be inherited in an autosomal dominant pattern or it may be due to a new gene mutation in an individual. The gene for neurofibromatosis type 1 is located on chromosome 17, and the gene for type 2 is located on chromosome 22. The gene for schwannomatosis has not yet been identified.

Neurofibromatosis Type 1

Neurofibromatosis type 1 is the most common type of neurofibromatosis. It occurs in about 1 in 4,000 births. The symptoms of NF1 are often present at birth or shortly after, and almost always are present by age 10 years.

Neurofibromatosis Type 2

Neurofibromatosis type 2 is less common than NF1. It affects about 1 in 40,000 people. The symptoms of neurofibromatosis type 2 are typically noticed between 18 to 22 years of age. The most frequent first symptom is hearing loss or ringing in the ears (tinnitus).

Schwannomatosis

Schwannomatosis is considered to be a rare form of neurofibromatosis. Only about 15% of cases seem to be inherited. Researchers have not yet identified the genetics involved in schwannomatosis.

_Sources:

"Neurofibromatosis Fact Sheet." Disorders. 13 Dec 2007. National Institute of Neurological Disorders and Stroke. 28 May 2008.

"Learning About Neurofibromatosis." Specific Genetic Disorders. 27 Nov 2007. National Human Genome Research Institute. 28 May 2008.