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Title: Frequent NF2 gene transcript mutations in sporadic meningiomas and vestibular schwannomas

Abstract

The gene for the hereditary disorder neurofibromatosis type 2 (NF2), which predisposes for benign CNS tumors such as vestibular schwannomas and meningiomas, has been assigned to chromosome 22 and recently has been isolated. Mutations in the NF2 gene were found in both sporadic meningiomas and vestibular schwannomas. However, so far only 6 of the 16 exons of the gene have been analyzed. In order to extend the analysis of an involvement of the NF2 gene in the sporadic counterparts of these NF2-related tumors, the authors have used reverse transcriptase-PCR amplification followed by SSCP and DNA sequence analysis to screen for mutations in the coding region of the NF2 gene. Analysis of the NF2 gene transcript in 53 unrelated patients with meningiomas and vestibular schwannomas revealed mutations in 32% of the sporadic meningiomas (n = 44), in 50% of the sporadic vestibular schwannomas (n = 4), in 100% of the tumors found in NF2 patients (n = 2), and in one of three tumors from multiple-meningioma patients. Of the 18 tumors in which a mutation in the NF2 gene transcript was observed and the copy number of chromosome 22 could be established, 14 also showed loss of (parts of) chromosome 22.more » This suggests that in sporadic meningiomas and NF2-associated tumors the NF2 gene functions as a recessive tumor-suppressor gene. The mutations detected resulted mostly in frameshifts, predicting truncations starting within the N-terminal half of the putative protein. 23 refs., 2 figs. 3 tabs.« less

Authors:
; ; ; ; ; ; ;  [1]; ;  [2]
  1. (Erasmus Univ., Rotterdam (Netherlands))
  2. (Bristol Myers-Squibb Pharmaceutical Research Institute, Princeton, NY (United States))
Publication Date:
OSTI Identifier:
7160082
Alternate Identifier(s):
OSTI ID: 7160082
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Human Genetics; (United States); Journal Volume: 54:6
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CENTRAL NERVOUS SYSTEM; NEOPLASMS; GENE MUTATIONS; DETECTION; DNA SEQUENCING; POLYMERASE CHAIN REACTION; DISEASES; GENE AMPLIFICATION; MUTATIONS; NERVOUS SYSTEM; STRUCTURAL CHEMICAL ANALYSIS 550400* -- Genetics

Citation Formats

Deprez, R.H.L., Groen, N.A., Zwarthoff, E.C., Hagemeijer, A., Van Drunen, E., Bootsma, D., Koper, J.W., Avezaat, C.J.J., Bianchi, A.B., and Seizinger, B.R.. Frequent NF2 gene transcript mutations in sporadic meningiomas and vestibular schwannomas. United States: N. p., 1994. Web.
Deprez, R.H.L., Groen, N.A., Zwarthoff, E.C., Hagemeijer, A., Van Drunen, E., Bootsma, D., Koper, J.W., Avezaat, C.J.J., Bianchi, A.B., & Seizinger, B.R.. Frequent NF2 gene transcript mutations in sporadic meningiomas and vestibular schwannomas. United States.
Deprez, R.H.L., Groen, N.A., Zwarthoff, E.C., Hagemeijer, A., Van Drunen, E., Bootsma, D., Koper, J.W., Avezaat, C.J.J., Bianchi, A.B., and Seizinger, B.R.. Wed . "Frequent NF2 gene transcript mutations in sporadic meningiomas and vestibular schwannomas". United States. doi:.
@article{osti_7160082,
title = {Frequent NF2 gene transcript mutations in sporadic meningiomas and vestibular schwannomas},
author = {Deprez, R.H.L. and Groen, N.A. and Zwarthoff, E.C. and Hagemeijer, A. and Van Drunen, E. and Bootsma, D. and Koper, J.W. and Avezaat, C.J.J. and Bianchi, A.B. and Seizinger, B.R.},
abstractNote = {The gene for the hereditary disorder neurofibromatosis type 2 (NF2), which predisposes for benign CNS tumors such as vestibular schwannomas and meningiomas, has been assigned to chromosome 22 and recently has been isolated. Mutations in the NF2 gene were found in both sporadic meningiomas and vestibular schwannomas. However, so far only 6 of the 16 exons of the gene have been analyzed. In order to extend the analysis of an involvement of the NF2 gene in the sporadic counterparts of these NF2-related tumors, the authors have used reverse transcriptase-PCR amplification followed by SSCP and DNA sequence analysis to screen for mutations in the coding region of the NF2 gene. Analysis of the NF2 gene transcript in 53 unrelated patients with meningiomas and vestibular schwannomas revealed mutations in 32% of the sporadic meningiomas (n = 44), in 50% of the sporadic vestibular schwannomas (n = 4), in 100% of the tumors found in NF2 patients (n = 2), and in one of three tumors from multiple-meningioma patients. Of the 18 tumors in which a mutation in the NF2 gene transcript was observed and the copy number of chromosome 22 could be established, 14 also showed loss of (parts of) chromosome 22. This suggests that in sporadic meningiomas and NF2-associated tumors the NF2 gene functions as a recessive tumor-suppressor gene. The mutations detected resulted mostly in frameshifts, predicting truncations starting within the N-terminal half of the putative protein. 23 refs., 2 figs. 3 tabs.},
doi = {},
journal = {American Journal of Human Genetics; (United States)},
number = ,
volume = 54:6,
place = {United States},
year = {Wed Jun 01 00:00:00 EDT 1994},
month = {Wed Jun 01 00:00:00 EDT 1994}
}
  • Neurofibromatosis type 2 (NF2) is a severe genetic disorder with an incidence of approximately 1 in 40,000 individuals and is characterized by the formation of multiple benign nervous system tumors. The clinical hallmark of NF2 is the bilateral occurrence of schwannomas on the eighth cranial nerve (vestibular schwannomas). Recently, it has been shown that loss or inactivation of a tumor suppressor gene located in chromosome band 22q12 is the molecular cause of NF2 tumorigenesis. Also, mutations in the NF2 gene have now been identified in patients with sporadic vestibular schwannomas (unilateral schwannomas). We have completed the screening of 80% ofmore » the NF2 coding sequence of DNA from 13 sporadic schwannomas and 2 schwannomas from NF2 patients. Using heteroduplex analysis and direct sequencing, we found 13 novel mutations located in 7 different exons with a small cluster (46% of the mutations) located in the central portion of the gene. All of the mutations were unique to single patients. In three tumors, both NF2 alleles were mutated. The types of mutations found include: small deletions ranging from 1 to 30 base pairs, nonsense mutations, a single missense mutation and a splice donor site alteration. It appears that small deletions are the most common type of NF2 gene mutation. We also have developed a dosage test based on quantitative PCR and hybridization with specific probes to detect the loss of heterozygosity. We found that 7 out of 15 schwannomas (47%) show loss of heterozygosity. We are currently extending the analysis to all of the NF2 exons and DNA from 60 additional schwannomas.« less
  • Neurofibromatosis type 2 (NF2) is an autosomal dominant disease with over 95% penetrance which predisposes gene carriers to develop multiple tumors of the central nervous system. The NF2 gene is a putative tumor suppressor gene which was previously mapped to the long arm of chromosome 22, and has recently been identified, using positional cloning techniques. The gene encodes a protein, schwannomin (SCH), which is highly homologous to the band 4.1 protein family. In an attempt to identify and characterize mutations which lead to the manifestation of the disease, we have used single strand conformation analysis (SSCA) to screen for germlinemore » mutations in all 17 exons of the NF2 gene in 59 unrelated NF2 patients, representing both familial and new mutations. A total of 27 migration abnormalities was found in 26 patients. Using direct sequencing analysis, the majority of these variants were found to result in nonsense, splice-site or frameshift mutations. Mutations identified in familial NF2 patients segregate in the family, and may prove to be useful tools for a simple and direct SSCA-based technique of presymptomatic or prenatal diagnosis in relatives of patients with NF2. This may be of particular importance in children of patients who have new mutations in the NF2 gene, where linkage analysis may not be feasible.« less
  • To assess the pathophysiological role of the RET protooncogene in sporadic pheochromocytomas, we examined the two regions of the gene in which molecular defects are specifically associated with the Multiple Endocrine Neoplasias (MEN) type 2A (exons 8-11) and type 2B (exon 16). The sequences of both regions were amplified by RT-PCR or PCR from tumor RNA and/or constitutive DNA. The amplified products were analyzed by denaturing gradient gel electrophoresis using chemical clamps. In 28 patients with unilateral sporadic tumors six RET mutations were found: three in the MEN2A region, and three in the MEN2B region. Five patients had missense mutations:more » two in the MEN2A region (C634W and D631Y), and three in the MEN2B region (M918T). Analysis of leukocyte DNA in three of these patients confirmed that RET mutations were only present in tumor DNA. The sixth patient had lost exon 10 in the tumor cDNA due to the deletion of the dinucleotide AG at the 3{prime} splice acceptor site of intron 9; this molecular defect was only found in the tumor DNA. Thus RET mutations of the MEN 2A and MEN 2B regions are also found in ca. 20% of sporadic pheochromocytomas. We describe new types of molecular defects of the RET protooncogene in the MEN2A region which involve non-cysteine residues and the loss of exon 10. Further studies should be extended to analyze the entire RET gene. These findings have a profound clinical impact for the management of patients with supposedly sporadic pheochromocytomas.« less
  • Five mutations in the low density lipoprotein (LDL) receptor (R) gene account for approximately 83% of cases of heterozygous familial hypercholesterolemia (hFH) in French Canadians in Quebec. The two most prevalent mutations are a >10kb deletion (10kb) of the promoter region resulting in a null allele (60.5% of cases) and a trp{sub 66}{r_arrow}gly missense mutation in exon 3 (ex3) resulting in a binding-defective R (11.7%). We have compared the phenotypic expression of these two mutations in 427 10kb hFH patients, 239 women (age 37.5 {plus_minus} 14.2 years) and 188 men (33.7 {plus_minus} 11.7) and 69 ex3 hFH patients, 42 womenmore » (40.6 {plus_minus} 14.3) and 27 men (36.8 {plus_minus}13.2). All data were analyzed separately for women and men. Tendon xanthomas were more prevalent in the 10kb (women 63%, men 68%) than in the ex3 patients (48%,48%). Total and LDL cholesterol were significantly higher in the 10kb patients with than without xanthomas but similar in ex3 patients. There were no significant differences in plasma lipoprotein concentrations between 10kb and ex3 patients with coronary artery disease (CAD) or between 10kb and ex3 patients without CAD. Among men with CAD, those with 10kb were significantly younger than those with ex3 (39.6 {plus_minus} 9.8, n=93 and 46.4 {plus_minus} 7.0, n=9, respectively). In both sexes, high plasma lipoprotein concentrations conferred an increased risk of CAD in 10kb but not in ex3 patients. Thus, as in homozygotes (previous study), the >10kb deletion is associated with more severe expression of FH than is the exon 3 mutation, although the plasma lipoprotein concentrations are not significantly different between the 10kb and ex3 heterozygotes. Since in homozygotes plasma cholesterol levels in 10kb are 60% higher than in ex3 patients, these observations suggest that the expression of the normal LDL-R allele compensates for the lack of a second allele in 10kb heterozygotes.« less
  • Purpose: To evaluate volumetric modulated arc radiotherapy (RapidArc [RA]), a novel approach allowing for rapid treatment delivery, for the treatment of vestibular schwannoma (VS). Methods and Materials: The RA plans were generated for a small (0.5 cm{sup 3}), intermediate (2.8 cm{sup 3}), and large (14.8 cm{sup 3}) VS. The prescription dose was 12.5 Gy to the encompassing 80% isodose. The RA plans were compared with conventional radiosurgery plans using both a single dynamic conformal arc (1DCA) and five noncoplanar dynamic conformal arcs (5DCA). Conformity indices (CI) and dose-volume histograms of critical organs were compared. The RA plan for the medium-sizedmore » VS was measured in a phantom using Gafchromic EBT films and compared with calculated dose distributions. Results: The RA planning was completed within 30 min in all cases, and calculated treatment delivery time (after patient setup) was 5 min vs. 20 min for 5DCA. A superior CI was achieved with RA, with a substantial decrease in low-dose irradiation of the normal brain achieved relative to 5DCA plans. Maximum doses to critical organs were similar for RA and 5DCA but were higher for 1DCA. Film measurements showed the differences between calculated and measured doses to be smaller than 1.5% in the high-dose area and smaller than 3% in the low-dose area. Conclusion: The RA plans consistently achieved a higher CI and decrease in areas of low-dose irradiation. This, together with shorter treatment delivery times, has led to RA replacing our conventional five-arc radiosurgery technique for VS.« less