Mutations and allelic loss of the NF2 gene in neurofibromatosis 2-associated skin tumors.

Schwannomas in the skin are frequently observed in neurofibromatosis 2 patients. In about one-quarter of the cases, skin tumors are the first clinical symptoms of this disease. Recognizing neurofibromatosis-2-related skin tumors is therefore important for early diagnosis of neurofibromatosis 2, especially in pediatric patients. In this study, we examined 40 skin tumors (36 schwannomas and four neurofibromas) from 20 neurofibromatosis 2 patients for NF2 mutations and allelic loss. NF2 mutations have been identified in blood from 15 (75%) of the 20 patients. We found NF2 mutations in five (13%) and NF2 allelic loss in 18 (45%) of the 40 analyzed tumors. Genetic alterations (allelic loss or mutation) were thus found in 50 (63%) out of the total of 80 examined alleles. In 17 (43%) tumors, alterations were found on both NF2 alleles. These results suggest that, as in the case of vestibular schwannomas and meningiomas, loss of functional NF2 gene product is also the critical event in the development of skin schwannomas. Identification of genetic alterations of the NF2 gene in skin tumors may help to identify neurofibromatosis-2-associated skin tumors, thus assisting in the diagnosis of neurofibromatosis 2 in ambiguous cases, and excluding neurofibromatosis 1 in unclear cases. We also report that the detection rate of constitutional mutations was higher in patients with skin tumors (65%) than in patients without skin tumors (40%).

Skin abnormalities in neurofibromatosis 2.

OBJECTIVE: To determine the prevalence, distribution, and histopathological conditions of skin abnormalities in neurofibromatosis 2 (NF2). DESIGN: Case series. SETTING: Hospital neurology department. PATIENTS: Consecutive sample of 88 patients with NF2 referred through workshops and publications, genetic counseling, and referral from neurosurgical departments; 81 patients met the National Institutes of Health, Bethesda, Md, NF2 diagnostic criteria and the diagnosis was established by mutation or segregation analyses in 7 patients. MAIN OUTCOME MEASURES: Prevalence, distribution, and type of skin abnormalities; histopathological features of 29 skin tumors selected primarily for medical indications. RESULTS: Fifty-two patients (59.1%) had 458 skin tumors, which were the first presenting sign in 27.3% of patients and usually appeared as flat dysplastic tumors or subcutaneous spherical nodular tumors of the peripheral nerves, on the limbs and trunk. Although 29 patients (33.0%) had café au lait spots, only 2 patients had as many as 6 spots. compared with patients with milder disease, patients with more severe disease had a significantly greater prevalence of skin tumors (24.0% and 71.0%, P < .001), more than 10 skin tumors (0.0% and 27.4%, P = .004), flat dysplastic skin tumors (8.0% and 54.8%, P < .001), and subcutaneous spherical nodular tumors (24.0% and 58.1%, P = .004). The histologically analyzed tumors were predominantly schwannomas, but 5 were neurofibromas and 2 were mixed tumors. CONCLUSIONS: The prevalence of some skin tumor types in NF2 is high and varies with disease severity, and schwannomas predominate in sampled tumors. The occurrence of neurofibromas is surprising, but could be explained by an interaction between neurofibromin and the NF2 gene product in regulating the ras proto-oncogene.

The neuroimaging and clinical spectrum of neurofibromatosis 2.

Neurofibromatosis 2 (NF2) is an autosomal dominant disease predisposing to multiple tumors of the central and peripheral nervous system. Bilateral vestibular schwannomas are the hallmark of the disease. To define the clinical spectrum of the disease, we performed gadolinium-enhanced magnetic resonance imaging of the brain and spine as well as neurological, dermatological, and ocular examinations in 48 patients with NF2 diagnosed with the National Institutes of Health diagnostic criteria. Patients were ascertained from patient workshops and publications and from referral as a result of vestibular schwannoma surgery. Vestibular schwannomas were found in 46 patients (96%, 43 bilateral and 3 unilateral), spinal tumors were found in 43 (90%), posterior subcapsular cataracts were found in 30 (63%), meningiomas were found in 28 (58%), and trigeminal schwannomas were found in 14 (29%). The presenting symptoms included hearing loss or tinnitus in 15 patients (31%), multiple or nonspecific symptoms in 15 (31%), skin tumors in 12 (25%), and ocular symptoms in 6 (13%). When the complete spine was imaged, spinal tumors were more common in patients with NF2 than has previously been reported. This is a noteworthy finding, because spinal tumors are a major cause of NF2 morbidity and mortality.

Epilepsy increases vulnerability of long-term face recognition to proactive interference.

Proactive interference (PI) decreases short- and long-term memory in healthy subjects. Neurological patients exhibit a heightened PI effect on short-term memory. It is, however, not known if PI affects long-term memory in neurological patients. We analyzed whether epilepsy heightens the negative effect of PI on long-term face memory. PI was induced by a list of 20 faces learned 24 hours prior to a target list of 20 faces. We tested immediate and 24-hour recognition for both lists. Twelve healthy controls and 42 patients with generalized epilepsy or temporal lobe epilepsy (TLE) were studied. PI led to a decrease in 24-hour recognition in patients with generalized epilepsy and TLE but not in controls. Thus, PI may cause long-term memory disturbances in epilepsy patients. PI was also associated with decreased short-term memory, but only in right TLE. This confirms the dominant role of the right temporal lobe in short-term face memory.

Sex differences in face recognition memory in patients with temporal lobe epilepsy, patients with generalized epilepsy, and healthy controls.

The influence of sex on face recognition memory was studied in 49 patients with temporal lobe epilepsy, 20 patients with generalized epilepsy, and 32 healthy controls. After learning 20 faces, serially presented for 5 seconds each, subjects had to recognize the 20 among 40 faces (including 20 new faces) immediately and 24 hours later. Women had better face recognition than men, with no significant differences between groups. Women's advantage was due mainly to superior delayed recognition. Taken together, the results suggest that sex has a similar impact on face recognition in patients with epilepsy and healthy controls, and that testing delayed face recognition raises sensitivity for sex differences. The influence of sex on face recognition in patients with epilepsy should be acknowledged when evaluating individuals or comparing groups.

[Type 2 neurofibromatosis without acoustic neuroma]. / Neurofibromatose Typ 2 ohne Akustikusneurinome.

Bilateral vestibular schwannomas (VSs) are the hallmark of neurofibromatosis type 2 and the crucial criteria for the diagnosis of this autosomal dominant disorder according to the criteria of the National Institutes of Health Consensus Statement. We describe three patients without VSs aged 47, 52 and 69 years, in whom a NF2 gene carrier status was diagnosed by spinal tumors, a cataract and schwannoma of cranial and peripheral nerves. In one case the diagnosis was ascertained by mutation analysis, which revealed a 163bp deletion in the NF2 cDNA, and by the fact that two daughters had the same deletion and NF2 according to the NIH criteria. Our finding suggests that patients with spinal tumors, multiple brain tumors, associated neurinomas or cataract might be carriers of a mutated NF2-gene. The study suggests that the NIH criteria are too restrictive, since NF2 seems to show up for a broader spectrum of phenotypes.

Supporting evidence of a gene for partial epilepsy on 10q.

A four-generation family with nine individuals with temporal partial epilepsy was studied. Detailed epilepsy history was investigated by structured interview. All putatively affected family members underwent a standardized electroencephalographic examination. The phenotype in the family was characterized by a short acoustic aura followed by rapid secondary generalization. To examine if the trait is linked to a region on 10q (interval D10S185-D10S1671), which has been reported in two other epilepsy families with similar phenotypes, linkage analysis was performed using nine markers covering the previously reported region. A maximum two-point LOD score of 2.1 at a recombination fraction of zero was obtained. All living affected individuals shared the same haplotype, while three unaffected at-risk adults did not. This result presents supporting evidence of a gene for partial epilepsy on 10q.

Spinal tumors in patients with neurofibromatosis type 2: MR imaging study of frequency, multiplicity, and variety.

OBJECTIVE: Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disorder leading to various tumors of the CNS, with vestibular schwannomas being the hallmark of the disease. We have observed multiple asymptomatic spinal lesions in patients who have a single symptomatic spinal tumor. Accordingly, we studied the frequency, multiplicity, and variety of spinal tumors in all patients with NF2 to determine what is characteristic of the disease. SUBJECTS AND METHODS: MR images of the entire spinal canal were made in 73 patients aged 4-69 years with NF2. The number, location, morphology, signal characteristics, and contrast medium uptake of the spinal tumors as seen on MR images were recorded and analyzed. Histopathologic proof of 22 spinal tumors was obtained in 19 patients. RESULTS: Spinal tumors were found on MR images in 89% of the patients studied. No location in any part of the spine was preferred. MR imaging showed intramedullary tumors in 24 patients (33%) (three ependymomas pathologically proven). Extradural and intradural extramedullary tumors were found on MR imaging in the cervical spine of 36 patients, the thoracic spine of 40 patients, and the lumbar spine of 49 patients. These tumors were meningiomas, schwannomas, or neurofibromas, three categories that could not be differentiated on the basis of the neuroradiologic findings, with ten schwannomas, seven meningiomas, and two neurofibromas pathologically proven. Extradural extramedullary tumors were found on MR imaging in the cervical spine of 12 patients, the thoracic spine of five patients, and the lumbar spine of 18 patients. A syrinx associated with a tumor was found in two patients. In 19 patients the variety of tumor types was confirmed by histologic examination. CONCLUSION: Patients with NF2 frequently have spinal tumors, which are often multiple and of various histologic types. The presence of multiple and different pathologic types of spinal tumors is highly suggestive of NF2.