Neurofibromatosis最新文献

The yellow-nonyellow pattern of the tortoiseshell guinea pig is presented as a model for the distribution of mutant and nonmutant neural-crest cells in von Recklinghausen neurofibromatosis (NF-1). The following hypotheses are offered to explain the developmental genetics of the variable phenotype. (1) The gene for NF-1 is somatically unstable; reverse somatic mutation occurs at a high frequency among the stem cells of clones of neural-crest cells in all affected individuals. (2) The normal reverted cells suppress the proliferation of residual mutant cells when both types are in close proximity. (3) At puberty, proliferation of normal cells decelerates, but proliferation in islands of residual mutant cells accelerates and results in the development of neurofibromas. (4) Plexiform neurofibromas occur when reverse mutation fails to occur or takes place relatively late within a large clonal population of mutant cells.

The autosomal dominant form of familial angiolipomatosis may be mistaken for peripheral neurofibromatosis (NF-1) due to the similarity of the family history and the occurrence of multiple subcutaneous masses, but histopathological examination of the tumors readily distinguishes these two diseases. We report here a case of familial angiolipomatosis, which was initially though to be neurofibromatosis, and the occurrence in this patient of a granular cell tumor similar to such tumors occasionally seen in neurofibromatosis. A review of the literature discloses intriguing parallels between familial angiolipomatosis and neurofibromatosis, suggesting that similar pathogenetic mechanisms may operate in both diseases.

In the first part of this paper, we show that intraperitoneal injection of adenosine into newborn mice causes multiple neural crest tumors, neural crest hyperplasia, and heterotopic melanin pigmentation. In the second part, we review published data to propose (1) that microtubule proteins, phosphorylated through the action of calmodulin-dependent kinase and cyclic adenosine monophosphate and the adenosine A2 receptor of neural crest cells, may participate in neurotransmission and (2) that at least some neural crest tumors may be associated with disorders of neurotransmission in embryonic neural crest cells.

The genetic analysis undertaken here shows that the direct (i.e. proband) method for calculating risk figures is not readily applicable to von Recklinghausen neurofibromatosis (NF-1); the selection of available sibling groups for analysis becomes biased in various ways, primarily because of the wide phenotypic variation of the disease. However, indirect methods of analysis confirm that NF-1 shows autosomal dominant inheritance with full penetrance. The existence of an unusually high mutation frequency is also confirmed. In this study it is estimated to be between 4.3 x 10(-5) and 6.5 x 10(-5). However, in contrast to the findings of others, among sporadic cases, both their distribution within sibships and parental ages at delivery did not differ from random distributions. An assessment of the degree of severity of NF-1 and comparisons of the sporadic cases with the familial cases produced no evidence of any clinical somatic differences between the two groups, likewise for psychiatric evaluations of the two groups. Apart from 2 cases with non-NF-1 segmental forms of NF, it was not possible to distinguish alternative forms of NF among the sporadic cases. A pair of monozygotic twins with NF-1 is discussed with reference to the nature and localization of their respective tumours, which are not identical, indicating the influence of factors beyond the mutant NF-1 gene itself on the manifestations of the disease. In a genealogical study involving about 3,000 ancestors of patients from Gothenburg with known NF-1, families with common ancestors were not found, nor was it possible to demonstrate a tendency to clustering in one geographical area or isolated locality.

Although the association of strokes and von Recklinghausen neurofibromatosis (NF-1) in young children is uncommon, it is obviously an important complication of this disorder. The few cases that have been described were reported primarily in the radiological literature. Moreover, most of the children reported were already known to have NF-1 or they had a positive family history for it. We report an infant who, at 7 weeks of age, suffered a stroke with resulting hemiparesis, prior to the development of other manifestations of NF-1. Pediatricians and neurologists need to be aware of this association and of the need for careful follow-up of infants with strokes, with particular attention to signs of neurofibromatosis.

The common (and definitive) intracranial tumors in patients with one form of neurofibromatosis (NF), bilateral acoustic NF (NF-2), are bilateral acoustic neuromas. In this study, we present 2 cases with what appears to be another form of NF, namely, NF-1, who showed bilateral enlargement of the internal auditory canals. Bilateral caloric responses were remarkably impaired in both cases; a unilateral sensorineural hearing loss was observed in 1. No tumor was demonstrated in the enlarged internal auditory canals in either case. Although the pathophysiology remains uncertain, some patients with NF-1 show abnormal cochleovestibular function in association with bilateral internal auditory canal enlargement without an acoustic tumor.

From 1975 to 1988 seventeen patients with neurofibromatosis type 1 and a disfiguring facial plexiform neurofibroma (FPN) were investigated. The FPN was left-sided in 13 patients. It was orbital/periorbital in 4, lower facial in 7 and involved the whole face in 6 subjects. Neuroimaging (n = 13) revealed a tumor (of optic pathways or basal ganglia) in 8, an ipsilateral middle cranial fossa arachnoid cyst in 2, multiple areas of high signal intensity (in T2-weighted magnetic resonance imaging) in 1, and normal findings in 2 patients. In NF-1 patients with FPN there seems to be a high incidence of intracranial tumors and possibly of arachnoid cysts. Our observation has to be confirmed in a larger patient series.

We report a case of an adult male with neurofibromatosis and chronic low back pain. Evaluation revealed an anterior sacral meningocele, pulmonary tuberculosis, and later in the course of his illness, an osteolytic tuberculous mass in the sacrum. The patient was treated medically with a good outcome. The nature of anterior sacral meningoceles and tuberculosis spondylitis, the differential diagnoses, and relevant treatment options are discussed.