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Parallels between tuberous sclerosis complex and neurofibromatosis 1: common threads in the same tapestry.

Neurofibromatosis type 1 (NF1) and tuberous sclerosis complex (TSC) represent two neurocutaneous disorders in which affected individuals develop tumors at an increased frequency. Although the clinical manifestations of these disorders are distinctive, the identification of the genes responsible for these disorders has demonstrated remarkable similarities on a molecular level between the NF1 and TSC tumor suppressor gene products. The NF1 and TSC2 gene products are hypothesized to function as growth regulators by modulating the activities of small GTPase molecules. The overlap between the functions of these tumor suppressor genes has yielded important insights into the molecular pathogenesis underlying each of these disorders and suggested possible pharmacological therapies specifically targeted for affected individuals.

Calcium-Calmodulin-Dependent Protein Kinases↗

Unusual form of recurrent giant cell granuloma of the mandible and lower extremities in a patient with neurofibromatosis type 1.

We report on a girl with familial neurofibromatosis type 1 (Nf1) who at age 11 had multiple osteolytic lesions of the right mandible and the distal femoral and proximal tibial metaphyses bilaterally. No other skeletal component was affected, and no abnormalities were present on skeletal radiographs of her parents. Histologic examination of the mandibular and right femoral lesions revealed a "multinucleated giant cell process." Results of repeated routine laboratory and bone metabolic studies were within normal limits. The lack of reliable histologic criteria and the diagnostic problems in distinguishing among central giant cell granulomata, giant cell tumors of the jaw, cherubism, brown tumors resulting from (occult) hyperparathyroidism, Jaffe-Campanacci syndrome, McCune-Albright syndrome, Noonan-like/multiple giant cell lesion syndrome, and multiple nonossifying fibromas of bone are discussed.

Bone Diseases, Developmental↗

A case of neurofibromatosis-Noonan syndrome with a central giant cell granuloma.

Neurofibromatosis Type 1 (NF1) is one of the most common autosomal dominant diseases affecting multiple systems including the vascular, skeletal, and central nervous system. Noonan syndrome (NS) is an autosomal dominant genetic disorder, associated with musculoskeletal and skin manifestations. Coexistence of central giant cell lesions in patients with both NS and NF1 were reported in the literature. Development of multiple central giant cell lesions in a patient with a Noonan syndrome has been referred to as Noonan-like syndrome. A few cases with features of NF1 and NS have been termed as NF1-NS. Here, we present a case of so-called NF-NS associated with a central giant cell lesion.

Adult↗

Medulloblastomas in neurofibromatosis type 1. Case report and literature review.

A 6-year-old girl, previously diagnosed with neurofibromatosis type 1 (NF-1) presented with ataxia and symptoms of raised intracranial pressure. Diagnostic work up disclosed a posterior fossa tumor. Histopathological study of the excised neoplasm showed a cerebellar medulloblastoma. We review the current literature and suggest that the association of medulloblastoma with NF-1 is not a chance occurrence, and that it might be pathogenically related. We propose that medulloblastoma should be added to the list of malignancies that are apt to occur in NF-1.

Ataxia↗

Spontaneous rupture of recurrent gastrointestinal stromal tumor associated with neurofibromatosis type 1.

The incidence of gastrointestinal stromal tumor (GIST) among neurofibromatosis type 1 (NF-1) patients is approximately 3.9-25%, and this relationship is generally considered to be non-coincidental. We report a patient with NF-1 who underwent laparotomy 3 times due to recurrent intra-abdominal tumor rupture with internal bleeding in the space of 13 years. The pathologic diagnoses were schwannoma, malignant peripheral nerve sheath tumor and GIST. Because of the similar histologic features of these tumors, we considered them to be of the same nature. Immunohistochemical staining can help in the differential diagnosis. We suggest that NF-1 patients with gastrointestinal symptoms receive further survey to rule out GISTs.

Antigens, CD34↗

Treatment of ADHD in neurofibromatosis type 1.

Forty-six of 93 children with neurofibromatosis type 1 (NF1) were found to satisfy the diagnostic criteria for attention-deficit-hyperactivity disorder (ADHD). Detailed comparisons were made among 20 children with NF1 and ADHD (12 males, 8 females; mean age 10.7 years, SD 2.2), 26 control children with NF1 (15 males, 11 females; mean age 11.3 years, SD 2.3), 14 control children with ADHD (7 males; mean age 9.9 years, SD 1.9), and 14 normally developing control children (7 males; mean age 11.2 years, SD 2.8). Children with NF1 and ADHD had the lowest IQ scores among the four groups. Test of Variables of Attention (TOVA) scores were poorer in the NF1-ADHD and ADHD control groups than in the two non-ADHD groups. Those with NF1 and ADHD were rated significantly poorer on the Child Behavior Checklist (CBCL) than were the NF1 control group. By administrating low doses (5 to 15 mg) of methylphenidate to the NF1-ADHD group, significantly improved TOVA scores were obtained. One-year follow-up yielded significantly improved CBCL scores. Our results show a high incidence of ADHD in NF1 and support an association between ADHD and learning and social problems in children with NF1. It was demonstrated that stimulant medication can lead to improvement in cognitive, academic, and social problems of children with NF1 and ADHD.

Attention↗

Social skills of children with neurofibromatosis type 1.

Children with neurofibromatosis type 1 (NF1) have difficulties in forming friendships and are often rejected by their peers. Factors that contribute to these negative social outcomes are poorly understood. This study investigated the social skills of children with NF1 and the influence of comorbid conditions, such as attention-deficit-hyperactivity disorder (ADHD) and specific learning dfficulties. We assessed and analyzed data from 79 children with NF1 (42 males, 37 females; mean age 11 years 6 months, SD 2 years 4 months) and 46 unaffected siblings (19 males, 27 females; mean age 12 years 1 month, SD 2 years 6 months; age range 8 to 16 years). Social skills were measured with the Social Skills Rating System. Children with NF1 had significantly poorer social outcomes than their unaffected siblings, and significantly poorer social skills in comparison with normative data. The presence of ADHD (in 39% of children with NF1) was the major risk factor for poor social functioning. Children with NF1 and ADHD had the poorest social skills and social outcomes when compared with children with NF1 only or children with NF1 and learning difficulties. These findings dispel the previous assumption that NF1 alone is associated with poor social functioning and has major implications for the development of effective interventions.

Adaptation, Psychological↗

Psychological disturbance and sleep disorders in children with neurofibromatosis type 1.

The objective of this study was to explore the behaviour, including sleep patterns, of children with neurofibromatosis type 1 (NF1). For this purpose we designed a cross-sectional descriptive survey conducted by postal enquiry with telephone follow-up. Simonds and Parraga's sleep questionnaire and the Strength and Difficulties Questionnaire were used to screen sleep patterns and behaviours respectively. Information was obtained for 64 children (39 male, mean age 10 y 7 mo, SD 4 y 1 mo, range 3 to 18 y; 57% response rate). There were increased numbers of children with NF1 achieving scores in the borderline and abnormal range for ratings of peer problems (p < 0.001), hyperactivity (p < 0.001), emotional symptoms (p < 0.001), and conduct disorder (p < 0.05). Total difficulties score was also high (p < 0.001) in the NF1 group. Only one group of sleep problems, parasomnias (in particular sleepwalking and sleep terrors), had a higher occurrence (p < or = 0.05) in the NF1 group than in the general population. Within the NF1 group, conduct problems (p < or = 0.05), hyperactivity (p < or = 0.01), emotional problems (p < or = 0.01), and the total difficulties score (p < or = 0.01) were all significantly higher in children with frequent sleep disturbance. We conclude that NF1 is associated with sleep and behavioural problems in a high proportion of children. Psychiatric conditions, e.g. attention-deficit-hyperactivity disorder, may be underdiagnosed on a large scale in children with NF1, and the use of simple screening tools in clinical settings may prove beneficial.

Adolescent↗

Learning disabilities in children with neurofibromatosis type 1: subtypes, cognitive profile, and attention-deficit-hyperactivity disorder.

Cognitive deficits are the most common complication in children with neurofibromatosis type 1 (NF1), and academic achievement is broadly affected. There is a lack of consensus in the literature regarding the frequency of general and specific learning disabilities, which seems to be related to the lack of a consensus on diagnostic criteria. The present study examined the frequency of specific learning disabilities (SLDs) in NF1, using an intellect-achievement discrepancy for diagnosis, as well as general learning difficulty associated with a lowering of general intellectual ability. The cohort consisted of 81 children with NF1 (43 males, 38 females; mean age 11y 6mo [SD 2y 4mo]; range 8y-16y 9mo) and 49 comparison children (20 males, 29 females; mean age 12y [SD 2y 6mo]; range 8y 2mo-16y 8mo). Problems with academic achievement were present in 52% of children with NF1; however, only 20% of the children with NF1 were diagnosed with an SLD (32% had more general learning problems). Only males with NF1 were at significant risk for SLD, and Verbal IQ<Performance IQ discrepancies were predictive of the presence of an SLD. There was a significant comorbidity of literacy-based learning disabilities and attention-deficit-hyperactivity disorder. We were able to define three subtypes of children with NF1 having distinct cognitive profiles, each with important implications for assessment and remediation.

Adolescent↗

A case of nasal glioma and neurofibromatosis. A new association.

A man of 25 with von Recklinghausen's neurofibromatosis (VR) developed nasal polyps. Subarachnoid haemorrhage occurred shortly after surgical excision and he died 9 weeks later. Post-mortem examination showed chronic hydrocephalus due to aqueduct stenosis. Histologically the polyps were a nasal glioma, a forme fruste of anterior encephalocoele not previously associated with VR, though other cranial defects are well recognized. Nasal glioma should be considered in the differential diagnosis of nasal lesions in VR.

Adult↗

Type 2 neurofibromatosis: the need for supraregional care?

The results of a U.K. study of 145 cases of type 2 neurofibromatosis has shown generally very poor operative results in terms of hearing and facial nerve preservation. Only 9 out of 118 vestibular schwannoma (acoustic neuroma) operations resulted in any clinically detectable hearing preservation and only 32 left the patient with good or normal (House grade I or II) ipsilateral facial nerve function. Although operation is still the definitive treatment of vestibular schwannoma (acoustic neuroma) and may be a lifesaving procedure, it appears that the evidence in favour of early operation is only valid when carried out in highly specialized centres. The special problems of NF2 cases who may go on to develop multiple spinal and cranial tumours making them wheelchair bound and blind as well as deaf warrants a careful experienced approach. Timing of operations may be critical for the enhancement of useful years of quality life. We therefore propose the setting up of a national NF2 register, with the management of cases at a few supraregional centres.

Adult↗

The restoration of hearing in neurofibromatosis type 2.

Central electrical stimulation of the auditory pathway can allow hearing in patients suffering from deafness localized in the auditory nerve. Developments in a multi-channel auditory brainstem implant based on the Nucleus Mini 22 Cochlear implant with transcutaneous signal transmission is discussed. The devices have been implanted in nine European patients suffering from Neurofibromatosis Type 2. Preliminary speech perception results and patient satisfaction are encouraging, and the data presented include some limited open speech recognition.

Cochlear Implants↗

Auditory rehabilitation in neurofibromatosis type 2: a case for cochlear implantation.

Cochlear implantation has a limited but definite role in the rehabilitation of certain neurofibromatosis type 2 (NF2) patients. The presence of a dead ear either before, or after, tumour removal does not necessarily imply loss of function in the eighth nerve; in some instances the hearing loss will be cochlear. Promontory or round window electrical stimulation may help to identify those individuals with surviving eighth nerve function. In such patients multichannel cochlear implantation promises a better level of audition than the auditory brain stem implant. This paper highlights such a case and the management problems are discussed.

Adolescent↗

The magnetless Clarion cochlear implant in a patient with neurofibromatosis 2.

We present our experience using the Clarion magnetless multichannel cochlear implant with a woman profoundly deafened following bilateral acoustic neuromata as a consequence of neurofibromatosis 2 (NF2). The right neuroma had been previously removed without an attempt at neural preservation. On the left, however, a posterior fossa approach had been taken with the aim of preserving hearing. Although the left cochlear nerve appeared to be undamaged at the end of the operation, no hearing thresholds could be elicited on post-operative audiometry, because of damage either to the cochlear nerve or to the blood supply to the cochlea. Round window electrical stimulation subsequently produced a perception of sound, confirming that the cochlear nerve was capable of functioning and that a cochlear implant would be effective. Because she would need regular magnetic resonance imaging (MRI) to monitor existing and future NF2 lesions, it was decided to use a magnetless Clarion implant, which has been shown to be MRI compatible. We report our experience of using the device in this case and discuss some of the issues related to the provision of cochlear implants to patients with NF2.

Adult↗

Neuronal growth factors from tumours of Von Recklinghausen neurofibromatosis.

Explants of 21 neurofibromas from 16 patients with Von Recklinghausen neurofibromatosis (NF-I) plus tumour tissue from 5 comparison patients and normal tissue from one of the NF-I patients were assayed for neuronal growth factor(s) using dissociated embryonic sensory neurons from chick embryo. Twenty-one of 21 neurofibroma explants released detectable quantities of neuronal growth factors, but only 2 of 8 non-neurofibroma tissue explants released activity. While antiserum to mouse nerve growth factor (NGF) fractionally inhibited neurite outgrowth induced by some of the neurofibromas, overall differences between assays containing antibody and controls reached statistical significance in 3 cases; in one case, explants of a separate tumour from the same patient had no detectable NGF-like activity. These data support the hypothesis that local release of neuronal growth factors in neurofibromas are responsible for neurites observed within these tumours. Further evidence that endoneurial tissue of peripheral nerve is a rich source of heterogeneous neuronal growth facts has been provided by these studies.

Axons↗

Growth curve analyses of neuropsychological profiles in children with neurofibromatosis type 1: specific cognitive tests remain "spared" and "impaired" over time.

Cognitive deficits in neurofibromatosis Type 1 (NF-1) have been documented in both the verbal and visuospatial domains. Previous investigations from our laboratory have determined a specific pattern of "spared" (Picture Arrangement, Picture Completion, and Rapid Automatized Naming) and "impaired" (Judgment of Line Orientation, Vocabulary, and Block Design) performance on cognitive measures in this population when compared to sibling-matched controls in pairwise designs. Growth curve analyses were conducted on these repeated measures in 19 patients with NF-1 and their siblings to investigate the longitudinal course and growth pattern of these spared and impaired measures. Results indicated that over time children with NF-1 do not catch up to their siblings on impaired measures, and they continue to perform similarly to their siblings on the spared measures. With respect to growth rates, on average across the 6 cognitive measures there was no significant difference between the groups. However, the variation among families for level of performance was estimated to be larger than variation among siblings within a family for 2 out of 6 cognitive measures (i.e., providing for these 2, Vocabulary and Rapid Automatized Naming, evidence of substantial familial correlation), suggesting that there is need to consider NF-1 associated deficits within a familial context.

Adolescent↗

Carboplatin therapy for optic pathway tumors in children with neurofibromatosis type-1.

Symptomatic optic pathway tumors (OPT) occur in 7% of children with neurofibromatosis type-1 (NF-1). Although tumor progression following diagnosis is unusual in such children, specific therapy may be necessary for patients with either severe or progressive disease. We reviewed the records of 9 children (6 girls, 3 boys) with NF-1 associated OPT who were treated with the second generation platinum compound carboplatin. Carboplatin was given at a dose of 560 mg/mm2 every 4 weeks for a mean of 15 cycles. The mean age at presentation of the OPT was 3.4 years. Eight children had abnormal ophthalmologic examinations at the time of diagnosis. Only 4 patients had documented evidence of progressive disease prior to the institution of therapy. No patient had evidence of progressive disease following therapy. Four patients had radiologic evidence of tumor shrinkage and 2 patients had definite improvement in vision. There was only minimal toxicity. In conclusion, carboplatin is a safe and effective treatment for OPT in children with NF-1. However, as disease stabilization of NF-1 associated OPT often occurs following clinical presentation, the clinician should document tumor progression or visual deterioration prior to the institution of therapy.

Antineoplastic Agents↗