Updated diagnostic criteria and nomenclature for neurofibromatosis type 2 and schwannomatosis: An international consensus recommendation.

Purpose: Neurofibromatosis type 2 (NF2) and schwannomatosis (SWN) are genetically distinct tumor predisposition syndromes with overlapping phenotypes. We sought to update the diagnostic criteria for NF2 and SWN by incorporating recent advances in genetics, ophthalmology, neuropathology, and neuroimaging.

Methods: We used a multistep process, beginning with a Delphi method involving global disease experts and subsequently involving non-neurofibromatosis clinical experts, patients, and foundations/patient advocacy groups.

Spinal ependymomas in neurofibromatosis Type 2: a retrospective analysis of 55 patients.

Object: The aim of this paper was to define the clinical characteristics of spinal ependymomas associated with neurofibromatosis Type 2 (NF2).

Methods: The authors retrospectively reviewed the clinical records of patients with NF2 who had imaging findings consistent with ependymomas and were seen at Massachusetts General Hospital between 1994 and 2007. Clinical characteristics of these patients were obtained from hospital records, imaging studies, surgical reports, and pathology reports.

Superficial neurofibromas in the setting of schwannomatosis: nosologic implications.

First described in the past decade, schwannomatosis is a syndrome distinct from neurofibromatosis 2 (NF2). It is characterized by the development of multiple schwannomas, sparing the vestibular division of cranial nerve VIII, and may also predispose to develop meningiomas. We report two female patients, a 27 and a 44 years old who developed multiple peripheral schwannomas, but without involvement of the vestibular nerves, satisfying clinical criteria for schwannomatosis.

Patient and physician attitudes regarding clinical trials in neurofibromatosis 1.

Neurofibromatosis 1 (NF1) is a multisystem genetic disorder that primarily affects the skin (freckling and café-au-lait macules), nervous system (neurofibromas, optic gliomas, and learning disabilities), and skeletal system (pseudoarthroses). The interest in pharmacological intervention for patients with NF1 has grown in recent years. However, little is known about the attitudes and priorities of patients, families, and physicians regarding participation in clinical trials.

A role for the p53 pathway in the pathology of meningiomas with NF2 loss.

The neurofibromatosis 2 locus (NF2) is inactivated through mutation and loss of heterozygosity (LOH) in 40-65% of all sporadic meningiomas, while the role of the p53 tumor suppression pathway in meningioma initiation and progression is still unclear. This study aims to determine if a p53 codon 72 arginine-to-proline polymorphism, found to be correlated with cancer development and cancer patient survival in other tumors, is associated with sporadic meningioma initiation or progression. We investigated Pro72 incidence in a cohort of 92 sporadic meningiomas and analyzed its association with histological grade (WHO classification) and with NF2 LOH (determined using polymorphic microsatellite markers on 22q).

Three-dimensional volumetrics for tracking vestibular schwannoma growth in neurofibromatosis type II.

Objective: Vestibular schwannomas (VS) are common, benign, VIIIth cranial nerve tumors. Treatment in patients with the genetic disorder neurofibromatosis type II (NF2) is complicated by their development of bilateral VS and risk of complete deafness. Intervention decisions consider several clinical factors including tumor size and growth rate evaluated using magnetic resonance imaging.

Alterations in the SMARCB1 (INI1) tumor suppressor gene in familial schwannomatosis.

Schwannomatosis is a third major form of neurofibromatosis that has recently been linked to mutations in the SMARCB1 (hSnf5/INI1) tumor suppressor gene. We analyzed the coding region of SMARCB1 by direct sequencing and multiplex ligation-dependent probe amplification (MLPA) in genomic DNA from 19 schwannomatosis kindreds. Microsatellite markers in the SMARCB1 region were developed to determine loss of heterozygosity (LOH) in associated tumors.

Immunohistochemical analysis supports a role for INI1/SMARCB1 in hereditary forms of schwannomas, but not in solitary, sporadic schwannomas.

The INI1/SMARCB1 protein product (INI1), a component of a transcription complex, was recently implicated in the pathogenesis of schwannomas in two members of a single family with familial schwannomatosis. Tumors were found to have both constitutional and somatic mutations of the SMARCB1 gene and showed a mosaic pattern of loss of INI1 expression by immunohistochemistry, suggesting a tumor composition of mixed null and haploinsufficient cells. To determine if this finding could be extended to all tumors arising in familial schwannomatosis, and how it compares with other multiple schwannoma syndromes [sporadic schwannomatosis and neurofibromatosis 2 (NF2)] as well as to sporadic, solitary schwannomas, we performed an immunohistochemistry analysis on 45 schwannomas from patients with multiple schwannoma syndromes and on 38 solitary, sporadic schwannomas from non-syndromic patients.

Modeling NF2 with human arachnoidal and meningioma cell culture systems: NF2 silencing reflects the benign character of tumor growth.

Meningiomas, common tumors arising from arachnoidal cells of the meninges, may occur sporadically, or in association with the inherited disorder, neurofibromatosis 2 (NF2). Most sporadic meningiomas result from NF2 inactivation, resulting in loss of tumor suppressor merlin, implicated in regulating membrane-cytoskeletal organization. To investigate merlin function in an authentic target cell type for NF2 tumor formation, we established primary cultures from genetically-matched meningioma and normal arachnoidal tissues.

Ocular pathologic findings of neurofibromatosis type 2.

Objective: To gain insight into the pathogenesis of neurofibromatosis type 2 (NF2) by investigating the ocular manifestations of this disease.

Methods: Using standard histologic techniques, immunohistochemistry, and electron microscopy, we described the ocular pathologic findings of a 34-year-old woman who died from complications of NF2.

Results: We identified 3 types of NF2-associated lesions: juvenile posterior subcapsular cataracts, epiretinal membranes, and an intrascleral schwannoma.

Dopa-responsive hypersomnia and mixed movement disorder due to sepiapterin reductase deficiency.

Sepiapterin reductase deficiency (SRD) is a rare, treatable disorder of monoamine metabolism with cognitive delay and l-dopa responsive movement disorder. We describe a patient with SRD and distinctive phenotypic feature of marked hypersomnolence. Our patient showed improvement with therapies directed at both serotonergic and dopaminergic deficiencies.

A negative feedback signaling network underlies oncogene-induced senescence.

Oncogene-induced senescence functions to limit tumor development. However, a complete understanding of the signals that trigger this type of senescence is currently lacking. We found that mutations affecting NF1, Raf, and Ras induce a global negative feedback response that potently suppresses Ras and/or its effectors.

Mutational spectrum of the NF2 gene: a meta-analysis of 12 years of research and diagnostic laboratory findings.

The NF2 tumor suppressor gene on chromosome 22 is a member of the protein 4.1 family of cytoskeletal elements. A number of single- and multiple-tumor phenotypes have been linked to alterations of NF2 since its characterization in 1993.

Temporal control of Rac in Schwann cell-axon interaction is disrupted in NF2-mutant schwannoma cells.

Schwann cell-axon interaction is the hallmark feature of peripheral nerves, yet the intracellular signals underlying this interaction are unknown. Schwann cells extend processes and migrate on developing axons before differentiation, requiring coordinated regulation of the Schwann cell cytoskeleton. Small GTPases of the Rho family, including Rho, Rac, and cell division cycle 42, regulate the actin cytoskeleton.

Unilateral vestibular schwannoma with other neurofibromatosis type 2-related tumors: clinical and molecular study of a unique phenotype.

Object: Although the manifestations of neurofibromatosis Type 2 (NF2) vary, the hallmark is bilateral vestibular schwannomas (VSs). The authors studied the clinical course and genetic basis of unilateral VSs associated with other NF2-related tumors.

Methods: Forty-four adults presenting with unilateral VSs and other NF2-related tumors were identified.

Inactivation patterns of NF2 and DAL-1/4.1B (EPB41L3) in sporadic meningioma.

The molecular basis of tumorigenesis and tumor progression in meningiomas is not fully understood. The neurofibromatosis 2 (NF2) locus is inactivated in 50-60% of sporadic meningiomas, but the genetic basis of sporadic meningiomas not inactivated at the NF2 locus remains unclear. Specifically, there is conflicting data regarding the role of the tumor suppressor gene DAL-1/4.

Diagnostic criteria for schwannomatosis.

The neurofibromatoses are a diverse group of genetic conditions that share a predisposition to the development of tumors of the nerve sheath. Schwannomatosis is a recently recognized third major form of neurofibromatosis (NF) that causes multiple schwannomas without vestibular tumors diagnostic of NF2. Patients with schwannomatosis represent 2.

Comparative pathology of nerve sheath tumors in mouse models and humans.

Despite the progress made in our understanding of the biology of neurofibromatosis (NF), the long-term clinical outcome for affected patients has not changed significantly in the past decades, and both NF1 and NF2 are still associated with a significant morbidity and a decreased life span. A number of NF1 and NF2 murine models have been generated to aid in the study of NF tumor biology and in the development of targeted therapies for NF patients. A single, universal pathological classification of the lesions generated in these murine models is essential for the validation of the models, for their analysis and comparison with other models, and for their future effective use in preclinical treatment trials.

Neurofibromatosis 2 in the pediatric population.

Neurofibromatosis 2 is a severe autosomal dominant disorder characterized by the occurrence of bilateral vestibular schwannomas and other benign tumors of the nervous system. Excellent natural history studies exist for adults with neurofibromatosis 2, but limited outcome data are available for children with neurofibromatosis 2. In this study, we present clinical data on 12 patients with neurofibromatosis 2 and age at diagnosis before 18 years.

Somatic instability of the NF2 gene in schwannomatosis.

Context: Schwannomatosis is a newly described form of neurofibromatosis of unclear pathogenesis.

Patient And Methods: We studied the NF2 locus on chromosome 22 in 7 tumor specimens resected from a 36-year-old man with schwannomatosis of the right ulnar nerve.

Results: Unrelated truncating NF2 gene mutations were detected in 4 tumor specimens.

Familial schwannomatosis: exclusion of the NF2 locus as the germline event.

Background: Schwannomatosis is a recently recognized disorder, defined as multiple pathologically proven schwannomas without vestibular tumors diagnostic of neurofibromatosis 2 (NF2). Some investigators have questioned whether schwannomatosis is merely an attenuated form of NF2.

Methods: The authors identified eight families in which a proband met their diagnostic criteria for schwannomatosis.

Molecular study of frequency of mosaicism in neurofibromatosis 2 patients with bilateral vestibular schwannomas.

Neurofibromatosis 2 (NF2) is a severe autosomal dominant disorder that predisposes to multiple tumours of the nervous system. About half of all patients are founders with clinically unaffected parents. The purpose of the present study was to examine the extent to which mosaicism is present in NF2 founders.