Definition
Neurofibromatosis type 2 is a relatively rare tumor predisposition syndrome characterized by progressive hearing loss that develops due to benign vestibular schwannomas on one or both sides, previously called acoustic neuromas. Other tumors, such as schwannomas, may also develop at the central and peripheral nerves, with meningiomas, gliomas, and neurofibromas occurring as well. In addition, premature reduction in visual acuity is indicative of a characteristic NF2 juvenile cataract.
Key Data
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Synonyms | NF2, central neurofibromatosis |
Gene | NF2 tumor suppressor gene |
Gene product | Merlin (moesin-ezrin-radixin-like protein) |
Function | Cytoskeletal protein, tumor suppression via contact-mediated (membrane) growth inhibition |
Heredity | Autosomal dominant (37%), de novo (63%, 1/3 of them mosaicism) |
Prevalence | 1:25.000-33.000 (1:150.000 in childhood) |
Genotype-phenotype correlation |
|
Penetrance | Nearly 100% during adulthood (by 30 years of age) |
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Diagnosis
Diagnostic Criteria (Manchester Diagnostic Criteria for NF2)
Additional Criteria:
Differential Diagnoses
Clinical Presentation
Signs of progressive hearing loss and tinnitus in young adulthood and mild courses of the disease are common.
With onset during childhood (30%), meningiomas, non-cranial schwannomas, mononeuropathies, and ocular symptoms (retinal hamartomas, cataract) are often prominent.
Classical Findings
NF2 tumor associated risk up to 16 years of age (According to Evans et al., AACR 2016)
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Likelihood of tumor symptoms | Likelihood of detecting tumors by MRI | Risk in Adulthood | |
---|---|---|---|
Vestibular schwannomas | 25% | 70-80% | 100% |
Cranial schwannomas | <1% | 20% | 40% |
Meningiomas | 10% | 15-20% | 70% |
Ependymomas | 0,2-0,5% | 10% | 25% |