Schwannomatosis

Identity

Atlas_Id	10122
Genes implicated in	SMARCB1
Note	A third major form of neurofibromatosis
Inheritance	Up to 90% of schwannomatosis are isolated cases. An annual incidence of newly identified cases was estimated to be approximately 1 in 1,700,000. Inheritance in familial cases is autosomal dominant with incomplete penetrance.

Clinics

Note	Clinical spectrum of schwannomatosis has similarity to neurofibromatosis type 2 (NF2) and overlap to some extent with that of NF2. Both disorders share the predisposition to multiple schwannomas.
Phenotype and clinics	Critetia for definite diagnosis: two or more pathologically sampled schwannomas and lack of evidence of vestibular nerve tumor on magnetic resonance imaging performed after age 18 years. Criteria for presumptive diagnosis: two or more pathologically ascertained schwannomas without symptoms of eighth nerve dysfunction at age above 30 years or two or more pathologically sampled schwannomas in an anatomically limited distribution without symptoms of eighth nerve dysfunction at any age
Neoplastic risk	Benign schwannomas of peripheral nerve.
Treatment	Surgical resection upon indication for pain and neurological symptoms. Electromyographical or electrohpysiological monitoring can be used to minimize the risk of iatrogenic injery to the nerve or spinal cord during surgery.
Prognosis	Schwannomatosis-associated tumors are basically of benign nature. Surgical outcome depends on anatomical localization and size of the tumor. No reduction in life-span expectation.

Cytogenetics

Inborn conditions

No special feature.

Genes involved and Proteins

Note	The genetic cause for schwannomatosis has not yet be identified. Linkage analysis has exclude the NF2 gene region and located the responsible locus to a 5 mega-basepair interval proximal to the NF2 gene on chromosome 22

Mutations
Note	Though alterations of the NF2 gene have been found in schwannomatosis-associated tumors, none of them has ever been found in any non-tumor tissues such as peripheral leukocytes of the patients.
Somatic	Somatic mutations and allele loss of the NF2 gene have been found in schwannomatosis-associated schwannomas.

Bibliography

Population-based analysis of sporadic and type 2 neurofibromatosis-associated meningiomas and schwannomas.

Antinheimo J, Sankila R, Carpén O, Pukkala E, Sainio M, Jääskelä J

Neurology. 2000 ; 54 (1) : 71-76.

PMID 10636128

Increasing the specificity of diagnostic criteria for schwannomatosis.

Baser ME, Friedman JM, Evans DG

Neurology. 2006 ; 66 (5) : 730-732.

PMID 16534111

Molecular analysis of the NF2 tumor-suppressor gene in schwannomatosis.

Jacoby LB, Jones D, Davis K, Kronn D, Short MP, Gusella J, MacCollin M

American journal of human genetics. 1997 ; 61 (6) : 1293-1302.

PMID 9399891

Diagnostic criteria for schwannomatosis.

MacCollin M, Chiocca EA, Evans DG, Friedman JM, Horvitz R, Jaramillo D, Lev M, Mautner VF, Niimura M, Plotkin SR, Sang CN, Stemmer-Rachamimov A, Roach ES

Neurology. 2005 ; 64 (11) : 1838-1845.

PMID 15955931

Multiple schwannomas: schwannomatosis or neurofibromatosis type 2?

Seppälä MT, Sainio MA, Haltia MJ, Kinnunen JJ, Setälä KH, Jääskelä JE

Journal of neurosurgery. 1998 ; 89 (1) : 36-41.

PMID 9647170

Citation

This paper should be referenced as such :

Kluwe, L

Schwannomatosis

Atlas Genet Cytogenet Oncol Haematol. 2007;11(1):59-60.

Free journal version : [ pdf ]   [ DOI ]

On line version : http://AtlasGeneticsOncology.org/Tumors/SchwannomatID10122.html

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