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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

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

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

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

[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

Neurofibromatoses.

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Humans

Aspects in neurofibromatosis from the viewpoint of dermatology.

The neurofibromatoses are a heterogenous set of conditions having clinical manifestations such as skin, nervous system, bone and eye disorders. The clinical pictures of the patients will obviously differ, and there is considerable variation of manifestations even within a family. During the last twenty-five years, one thousand and two hundred patients with neurofibromatosis were personally examined. Almost all our patients had classical von Recklinghausen disease. But in addition to these cases, there are 28 cases of NF-2 and 10 patients which we call multiple neurilemmomatosis. Also, there are related groups of patients with conditions which were not neurofibromatosis, such as 40 cases of localized multiple neurofibromas and 61 cases of localized café-au-lait spots. The features of neurofibromatosis in Japan are not different, compared with foreign countries, except increased pigmentation is more common. In addition to café-au-lait spots, some 20% of Japanese neurofibromatosis patients have pigmentary conditions which I termed hairy fuscoceruleus spots. These spots are blue-brown in colour, and one can see coarse hairs in them. Our recent study indicates that the patients with neurilemmomatosis have loss of heterozygosity of chromosome 22, the same position as the site of patients with NF-2. Neurilemmomatosis may be classified as an NF-2 without acoustic tumors.

Adolescent

Constitutional ring chromosomes and tumour suppressor genes.

The types of malignancy reported in carriers of constitutional ring chromosomes r(11), r(13), and r(22) are concordant with the chromosomal assignment of tumour suppressor loci associated with Wilms' tumour, retinoblastoma, and meningioma. It is suggested that the somatic instability of ring chromosomes may play a role in this association and that constitutional ring chromosomes may be a source for mapping of tumour suppressor loci with the potential for covering most or all of the human genome. The hypothesis predicts the presence of a locus on chromosome 10 associated with follicular carcinoma of the thyroid, in line with previous cytogenetic findings of rearrangements involving chromosome 10 in thyroid tumours, and a locus on chromosome 22 associated with testicular cancer. Development of neurofibromatoses (NF) that do not fulfil the clinical criteria of neurofibromatosis type 2 (NF2) in carriers with r(22) suggests either the presence of an additional NF locus on chromosome 22 or that ring chromosome mediated predisposition to somatic mutation of a specific tumour suppressor may be associated with atypical development of features usually associated with germline mutations.

Adenocarcinoma

[MRT in neurofibromatosis and tuberous sclerosis].

The relatively rare neurocutaneous syndromes may produce neurological symptoms during childhood. After closure of the fontanelle, the radiological methods of choice are CT and MRT. The value of these two methods is demonstrated by twelve examples (eight neurofibromatoses, four tuberous scleroses). CT is superior to MRT in being able to show calcification; it is therefore the method of choice for tuberous sclerosis. On the other hand, MRT may show foci of neurofibromatosis; these can hardly be seen on CT. In order to show cerebral lesions in these two conditions, T2-weighted sequences are necessary.

Adolescent

Contemporary management of neurofibromatosis.

The neurofibromatoses are two distinct entities with different genetic origins. The phenotypic expressions and required treatments are different. The devastating nature of neurofibromatosis-2 may be more effectively controlled through the application of advanced imaging techniques and contemporary neurotologic procedures. The most common manifestation of neurofibromatosis-2 is that of bilateral acoustic neuromas. The eventual total bilateral sensorineural deafness associated with this condition can be obviated in selected cases if the diagnosis is established early. Follow-up data are reported for three patients in whom hearing was preserved in at least one ear. When removal with hearing preservation is not possible, subtotal tumor removal with decompression of the internal auditory canals may delay progression of hearing loss. A new approach to tumors of the pterygomaxillary fossa that have extended to the middle cranial fossa has been successfully applied and is described.

Adolescent

NIH conference. Neurofibromatosis 1 (Recklinghausen disease) and neurofibromatosis 2 (bilateral acoustic neurofibromatosis). An update.

The neurofibromatoses comprise at least two autosomal dominant disorders affecting an estimated 100,000 Americans with clinical manifestations that may require care from every type of clinician. Neurofibromatosis 1 and neurofibromatosis 2 have in common the occurrence of many neurofibromas but are distinctly different clinical disorders. The disease genes are on different chromosomes. Magnetic resonance imaging, particularly with gadolinium enhancement, has generally supplanted other techniques for visualizing brain, spinal, and other neural tumors in both disorders. The technique has rekindled the controversy over the nature and frequency of optic pathway tumors in patients with neurofibromatosis 1 and has revealed, throughout the brains of young patients, bright lesions that have uncertain clinical consequences and unknown pathologic bases. In patients with neurofibromatosis 2, small acoustic neuromas can be seen, leading to the possibility of excision with preservation of hearing and facial nerve function. Abnormal hearing may occur to excess in patients with neurofibromatosis 1, but acoustic neuroma has never been documented. In patients with neurofibromatosis 2, a battery of audiologic tests has a high positive predictive power. Lisch nodules or iris hamartomas, probably a universal sign in adults with the neurofibromatosis 1 gene, cause no problem with vision. Posterior capsular lens opacity in patients with neurofibromatosis 2 is a helpful diagnostic sign and a potential source of additional handicap in persons at risk for impaired hearing. Progress in the clinical delineation of the disorders has been matched with considerable research into the still obscure pathogenesis of the disorders. Such rapid advances may necessitate reconsideration of the conclusions of the National Institutes of Health Consensus Development Conference on Neurofibromatosis, especially those on the categories of persons in which a neurofibromatosis should be considered and the need for caution in recommending surgery. Watchful waiting may often be the best management for acoustic neuromas in neurofibromatosis 2.

Chromosome Aberrations

Respiratory function in severe scoliosis before and after treatment (a review of 76 cases).

The authors carried out a study of respiratory function in seventy six patients suffering from severe scoliosis of different types; forty five idiopathic, sixteen poliemyelitic, ten congenital, and five neurofibromatosic. The age incidence was from a minimum of eleven years to a maximum of thirty three, with the average around fifteen years. The site of the deformity was predominantly dorsal (fifty cases), though there were also lumbar and dorso-lumbar types. The average angle of curvature (Cobb) before treatment was 110 degrees. Arthrodesis by the Harrington technique was carried out on all patients after correction with a Risser-type plaster in sixty nine cases, and Halo-traction in seven cases. The post operative period in plaster was about eight months. Spirometric tests were carried out before treatment, after preoperative correction, and two to three years after operation, always with the chest out of plaster. The results of these tests are expressed as percentage reductions in the maximum ventilation compared with the average normal values in the tables reported by Baldwin et al. (1948). The values obtained before commencing treatment showed that lumbar scoliosis even if very severe, never leads to severe respiratory deficits. There is no linear relationship between the severity of the curve and the respiratory deficit, though there is a general connection between them. Tests of respiratory function were carried out after corrective treatment, both before and after operation and at a two year follow up. There was an overall average improvement of 10% in the respiratory deficit, with a maximum of about 20% in a group of twenty two patients with the most severe deficit before commencing treatment. Follow-up three years after operation showed the improvement in respiratory fimction had been maintained. The authors conclude that arthrodesis by the Harrington technique does not diminish the respiratory gain achieved by pre-operative correction. On the contrary, it stabilises it and maintains it over the three year follow-up period of the present survey.

Adolescent

[Phakomatosis: anatomo-clinical expressions of urological interest].

Up to date etiopathogenetic knowledge of phakomatoses allows a more rational classification as compared to the known ones, based on anatomopathological and/or clinical features. Some genes have been identified, which are correlated with neurofibromatoses, tuberous sclerosis and other conditions, through general biologic mechanisms (derivatives of the embryonic neural crest; nerve growth factor and its receptor; oncogenes and antioncogenes, etc.). A prenatal predictive value from those genetic connections can also ensue. The new diagnostics, both by imaging and by laboratory techniques, may affect the therapeutic choices, as for as urological involvement is concerned.

Adrenal Gland Neoplasms

[Genetics of neurofibromatosis: recent progress and prospects].

Two forms of neurofibromatosis are currently described. Von Reckinghausen Neurofibromatosis (NF 1) is the classic and common form, recently localised to chromosome 17. Neurofibromatosis type 2 (NF 2) or bilateral acoustic Neurofibromatosis, formerly the "central form" of von Reckinghausen disease, is characterized by multiple brain tumors, most often bilateral acoustic neuromas. The NF 2 mutation lies on the long arm of chromosome 22. The two forms predispose to benign or malignant familial tumors, derived from neural crest germ lines, such as Schwann cells. Rapid progress in the understanding of mechanisms underlying neurological tumor formation is expected in these inherited diseases. Molecular biology will allow the precise identification of genes responsible for the neurofibromatose syndromes. Practical applications, such as screening of individuals at risk for the disease will soon be available. Medical follow-up and genetic counselling should improve as a result of these advances.

Genes, Neurofibromatosis 1

Neurofibromatosis update.

This paper presents a review dealing with three major aspects of a modern understanding of the disorders known collectively as the neurofibromatoses (NF). In one section, the focus is on NF heterogeneity, clarifying the distinction between NF-1, NF-2 and atypical forms of NF. In another section, the focus is on NF-1 neural-crest tumors, with particular emphasis on the four types of neurofibromas (cutaneous, subcutaneous, nodular plexiform and diffuse plexiform), schwannomas, astrocytomas and neurofibrosarcomas. In the final section, focus is on NF-1 nontumor features, both as a clinical guide and as a reminder of the breadth of concerns that a pathogenetic schema will have to consider.

Adrenal Gland Neoplasms

Fine needle aspiration cytology of malignant schwannoma metastatic to the breast.

A case of malignant schwannoma metastatic to the breast is reported. The tumor was found as a solitary breast lump in a 43-year-old woman and was clinically considered to be a primary tumor. Fine needle aspiration (FNA) smears of the mass were interpreted cytologically as a malignant neurogenic tumor, compatible with a malignant schwannoma. The patient did not have multiple neurofibromatoses. Eight months previously, an excision of a solitary nodule located in the left axilla had been performed in another hospital. Comparison of the histologic section from that excision with the FNA confirmed that the breast tumor was a metastatic malignant schwannoma, and the patient was treated accordingly.

Adult