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At least 19 recordsLinked to original sources
PubMed2004

The neurofibromatoses: hereditary predisposition to multiple peripheral nerve tumors.

Neurosurgeons must be aware of the neuro-fibromatoses because they frequently present with nervous system tumors. Such patients develop numerous peripheral nerve sheath tumors; fortunately, only a few of these tumors are symptomatic or malignant. The tumor burden in individual patients can be remarkable, however, producing significant morbidity and requiring extensive or repeated care by a skilled neurosurgeon. Because it is impossible to predict which of the deep neurofibromas will undergo malignant transformation, it behooves clinicians and patients to be aware of any change in symptoms or growth of tumors, because early resection of MPNST offers the only chance for cure. Neurosurgical professionals should be familiar with the diagnostic criteria of the neurofibromatoses, because the patient who presents with an initial neurofibroma or schwannoma immediately falls into a category in which those disorders must be ruled out. In this regard, a family history of nerve sheath tumors is revealing and should prompt referral for a clinical genetics evaluation. Cutaneous manifestations of NFI can confirm the diagnosis at initial presentation. Missing the initial presentation of a patient with NF2 can lead to marked morbidity, such as deafness,because surveillance for subsequent tumors was inadequate. Tumorigenesis in all neurofibromatoses involves loss of tumor suppressor genes. These disorders illustrate that the two-hit loss of tumor suppressor gene model, which applies best for NF2, is oversimplified. As with most cancers,a theory of multistep progressive acquisition of genetic changes that promote unregulated grow this emerging in schwannomatosis. In addition, the hyperpigmentation and learning disability of NF 1 highlight that loss of one copy of the gene is sufficient to cause nontumoral manifestations of the disorder. Genetic counseling and testing have an important role in the diagnosis of NFI and NF2 as well as in the management of all the neurofibromatoses.

Genetic Predisposition to Disease↗
PubMedDate not supplied

Ophthalmological issues in the neurofibromatoses.

The neurofibromatoses are a set of at least two distinct disorders characterized by the development of nerve sheath tumors and diverse other features. Both are genetically determined as autosomal dominant traits, and both genes have been identified, with resultant major insights into pathogenesis. The neurofibromatoses have prominent effects on the visual system, which are important both for diagnosis and clinical management. This review focuses on clinical aspects of the neurofibromatoses, highlighting ophthalmological issues and recent advances in molecular genetics.

Adolescent↗
PubMed1992

Nosological considerations of the neurofibromatoses.

We are on the threshold of evaluating the NF1 and NF2 loci with respect to variant forms of the neurofibromatoses. Genetic mapping of NF1, gene cloning and characterization of its encoded product, neurofibromin, provides a framework for the evaluation of the variant forms of NF. This may also apply to NF2 variant forms in the near future. The mapping approach in evaluating variant forms of NF should begin with the rigorous clinical assessment of familial cases whereby the establishment of genetic linkage in families with overlap syndromes might determine if either NF1, NF2, or a separate locus is involved in the phenotype. Conditions mapping to the NF1 locus could then be screened for mutations in hopes of identifying the etiologies of the variant forms of NF. Mutation identification should provide a molecular-based classification scheme for the variant forms of NF, now tentatively divided into alternative and related forms. It is expected that the nosology of the neurofibromatoses will most certainly change as more is learned of the NF1 and NF2 loci.

Diagnosis, Differential↗
PubMed2001

[Neurofibromatoses. Types, classification and diagnostic criteria].

According to the worldwide-accepted classification of the neurofibromatoses only neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2) are well defined. Other described forms of neurofibromatosis are rare. The aim of this paper is to review the contemporary classification and diagnostic criteria of the different types of neurofibromatoses.

Humans↗
PubMed1993

Molecular biology of the neurofibromatoses.

The molecular biology of the neurofibromatoses is fascinating, both because the process of obtaining the data has been instructive in investigating other genetic disorders and because those data will be so informative about physiological and pathological phenomena well beyond the neurofibromatoses themselves. In this brief overview, the highlights of the molecular biology of NF-1 and NF-2 are noted and their significance considered in terms of key clinical facts.

Animals↗
PubMed1988

The neurofibromatoses. What do we know about them?

These are exciting times for patients and physicians concerned with the neurofibromatoses. These disorders have been known to medicine for more than 100 years, and now there is hope of achieving a thorough understanding of their pathogenesis. Despite this optimism, the need for careful clinical management of these patients and for solid clinical research to better define the natural history of the disorders will remain for some time. Success of the research depends in large part on studying patients with carefully documented diagnoses, and long after the genes for the neurofibromatoses are identified, work will go on to apply the new knowledge to the benefit of those affected with the disorders.

Adolescent↗
PubMed2005

[Neurofibromatoses and tuberous sclerosis].

Neurofibromatoses and tuberous sclerosis have specific genetic epidemiology, diagnostic criteria and management. These diseases are autosomal dominant disorders linked to mutations on tumour suppressor genes. Their management is mainly clinically oriented and aimed at managing potential complications.

Humans↗
PubMed1994

New insights into the neurofibromatoses.

The two neurofibromatoses, neurofibromatosis type 1 (NF1) and type 2 (NF2), have been greatly advanced by the cloning of their respective disease genes. Although NF1 and NF2 are clinically distinct disorders, they represent diseases caused by disruption of tumor suppressor genes. Tumor suppressor genes encode proteins involved in the proper regulation of cell differentiation and proliferation and their disruption presumably predisposes to tumor formation. This year it was demonstrated that the NF1 gene fulfills the genetic criteria for a tumor suppressor gene and that its expression is altered in a number of human malignancies unrelated to NF1. The protein product of the NF1 gene, neurofibromin, was shown to be associated with cytoplasmic microtubules and this interaction may modulate one of neurofibromin's functions. This year also witnessed the cloning of the NF2 gene and the identification of the predicted protein as a member of a family of cytoskeleton-associated proteins.

Cell Differentiation↗
PubMed1989

Occurrence of both neurofibromatoses 1 and 2 in the same individual with a rapidly progressive course.

We describe a family in which the father had neurofibromatosis-1 and the mother neurofibromatosis-2. Their son presented at the age of 8 years with bilateral acoustic neuromas, meningioma, and numerous neurofibromas. We believe that the occurrence of the genes responsible for both forms of neurofibromatosis in the same patient had a synergistic effect on the early rapid growth of neurofibromatoses 1 and 2 neoplasms.

Adult↗
PubMed1990

Prenatal diagnosis of the neurofibromatoses.

This article reviews the application of genetic linkage analysis to molecular prenatal diagnosis using the neurofibromatoses as an example. The clinical manifestations and diagnostic criteria for these diseases are reviewed first, followed by a brief description of the principles underlying genetic linkage analysis, the detection of DNA polymorphisms and their application to the cloning of the NF1 gene. The last two sections review the molecular diagnosis and some of the problems in prenatal genetic counseling for NF1.

Blotting, Southern↗
PubMed1983

[Tumors of the central nervous system in biopsy and autopsy material. 7th communication: neurinomas and neurofibromatoses with CNS involvement].

In 1,491 autopsy cases with CNS tumors observed at the Pathological Institute of the Medical Academy of Erfurt in the period from 1953 to 1976 (54,946 autopsies) 72 cases (4.8%) with neurinomas were found. They comprise 67 solitary neurinomas, 1 bilateral acoustic neurinoma without other signs of neurofibromatosis, and 4 cases of neurofibromatosis with neurinomas of the CNS. Among the 68 cases with CNS neurinomas (neurofibromatoses excluded) 87% were acoustic neurinomas, 12% spinal tumors, and 1 case was located in the trigeminal nerve. In 60 (88%) of these 68 cases, the neurinoma was operated upon or clinically diagnosed, resp. The diameter of 18 (26%) neurinomas of the autopsy material was larger than 5 cm. Patients in the 6th decennium predominated in this series. The sex distribution revealed a preponderance of females over males (3:1). In 3 cases further CNS tumors (ependymoma, glioblastoma, meningioma) were found. Additionally, 3 cases had carcinomas of different localization (Table 5). Following tumors were seen in 9 cases of Morbus Recklinghausen with CNS involvement: 4 cases with multiple neurinomas, 3 meningiomas, 1 astrocytoma, 2 glioses and 1 angiomatous malformation (Table 6). Among 1,670 CNS tumors in biopsy material, 144 (8.6%) were neurinomas. 60% of them were located in the nervus acusticus, 40% spinally, mainly in the thoracic region. The 6th decennium was most affected, and females were more frequent than males (2:1) in our material. Nearly all CNS neurinomas were benign. Only 1 spinal tumors was classified as a malignant neurinoma. 2 of the 9 cases with Morbus Recklinghausen had malignant neurogenic tumors (neurofibrosarcomas).

Adolescent↗
PubMed1999

The neurofibromatoses. An overview.

The last two decades have seen clinical and molecular delineation of the different forms of neurofibromatosis. Differentiation of these forms is not just an academic exercise: their natural history, management and genetic counselling are quite different. Of the numerical classifications of neurofibromatosis proposed in the past, only neurofibromatosis type 1 (Nf1) and neurofibromatosis type 2 (Nf2) are now well delineated clinically and have been shown to be distinct at the molecular level. For both forms of neurofibromatosis, patients with clinical generalised disease have been demonstrated to be mosaic at the molecular level, and features of segmental or mosaic Nf1 and Nf2 have been delineated. Other reported forms of neurofibromatosis are rarer; they include Watson syndrome, hereditary spinal neurofibromatosis, familial intestinal neurofibromatosis, autosomal dominant café-au-lait spots alone, autosomal dominant neurofibromas alone, and schwannomatosis, the latter believed to be a variant of Nf2. Further delineation is needed for individuals having overlapping features of Noonan's syndrome and neurofibromatosis (the so-called Noonan/neurofibromatosis syndrome) and the syndrome of "multiple naevi, multiple schwannomas and multiple vaginal leiomyomas". In this article we review the forms of neurofibromatosis which we believe are true clinical entities. Particular attention is given to the neurological manifestations of neurofibromatosis.

Humans↗
PubMed1992

[Magnetic resonance imaging of neurofibromatoses].

Neurofibromatosis is classified into two types. Type 1, NF1 or von Recklinghausen's disease, consists of skin and bone lesions as well as central nervous system tumours arising at the expense of glial tissue: optic tract gliomas, glioblastomas, astrocytomas and "hamartomas". Type 2 consists almost exclusively of CNS tumours arising at the expense of nerve envelopes: Schwannomas, meningiomas.

Adult↗
PubMed2001

The neurofibromatoses: when less is more.

The study of cancer predisposition syndromes presents unique opportunities to gain insights into the genetic events associated with tumor pathogenesis. Individuals with two inherited cancer syndromes, neurofibromatosis 1 (NF1) and neurofibromatosis 2 (NF2), develop both benign and malignant tumors. The corresponding genes mutated in these two disorders encode tumor suppressor proteins, termed neurofibromin (NF1) and merlin (NF2), which function in novel ways to regulate cell growth and differentiation. Neurofibromin inhibits cell proliferation, at least in part, by modulating mitogenic pathway signaling through inactivation of p21-ras. In contrast, merlin may act as a membrane-associated molecular switch that regulates cell-cell and cell-matrix signals transduced by cell surface receptors. Significant progress in our understanding of the genetics and biology of NF1 and NF2 has elucidated the roles of these genes in tumor initiation and progression.

Animals↗