• Localization of the 17q breakpoint of a constitutional 1;17 translocation in a patient with neuroblastoma within a 25-kb segment

• Loss of heterozygosity for the NF2 gene in retinal and optic nerve lesions of patients with neurofibromatosis 2.

• Linkage disequilibrium and founder effect analysis of the NF1 gene in French Canadians from the Quebec population.

• Exclusion of candidate genes and loci for multiple lentigines syndrome.

• [Multiple lentigines (LEOPARD) syndrome. Case reports and review of the literature]

• Mutant products of the NF2 tumor suppressor gene are degraded by the ubiquitin-proteasome pathway.

• Polyneuropathy in neurofibromatosis 2: clinical findings, molecular genetics and neuropathological alterations in sural nerve biopsy

• Active Alu element "A-tails": size does matter.

• Clinical aspects of neurofibromatosis 1.

1
UI - 12203774
AU - Van Roy N; Vandesompele J; Berx G; Staes K; Van Gele M; De Smet E; De
TI - Paepe A; Laureys G; van der Drift P; Versteeg R; Van Roy F; Speleman F Localization of the 17q breakpoint of a constitutional 1;17 translocation in a patient with neuroblastoma within a 25-kb segment located between the ACCN1 and TLK2 genes and near the distal breakpoints of two microdeletions in neurofibromatosis type 1 patients.
SO - Genes Chromosomes Cancer 2002 Oct;35(2):113-20
AD - Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium.
We have constructed a 1.4-Mb P1 artificial chromosome/bacterial artificial chromosome (PAC/BAC) contig spanning the 17q breakpoint of a constitutional translocation t(1;17)(p36.2;q11.2) in a patient with neuroblastoma. Three 17q breakpoint-overlapping cosmids were identified and sequenced. No coding sequences were found in the immediate proximity of the 17q breakpoint. The PAC/BAC contig covers the region between the proximally located ACCN1 gene and the distally located TLK2 gene and SCYA chemokine gene cluster. The observation that the 17q breakpoint region could not be detected in any of the screened yeast artificial chromosome libraries and the localization of the 17q breakpoint in the vicinity of the distal breakpoints of two microdeletions in patients with neurofibromatosis type 1 suggest that this chromosomal region is genetically unstable and prone to rearrangements. Copyright 2002 Wiley-Liss, Inc.

2
UI - 12210058
AU - Chan CC; Koch CA; Kaiser-Kupfer MI; Parry DM; Gutmann DH; Zhuang Z;
TI - Vortmeyer AO Loss of heterozygosity for the NF2 gene in retinal and optic nerve lesions of patients with neurofibromatosis 2.
SO - J Pathol 2002 Sep;198(1):14-20
AD - National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. ccc@helix.nih.gov
Individuals affected with the neurofibromatosis 2 (NF2) cancer predisposition syndrome develop specific ocular lesions. To determine whether these lesions result from altered NF2 gene expression, microdissection and PCR were used to investigate 40 ocular lesions from seven eyes of four NF2 patients for LOH, with markers that flank the NF2 gene on chromosome 22q. NF2 protein (merlin) expression was also evaluated in these lesions, using immunohistochemistry. Retinal hamartoma was observed in all seven eyes, including one with combined pigment epithelial and retinal hamartoma (CPERH). Retinal tufts were present in four eyes (three patients), retinal dysplasia in two eyes (two patients), optic nerve neurofibroma in one eye, iris naevoid hyperplasia in two eyes (two patients) and pseudophakia in all eyes. Markers were informative in three patients (six eyes from three unrelated families). One patient was non-informative due to prolonged decalcification. All retinal and optic nerve, but not iris lesions, demonstrated consistent LOH for the NF2 gene. Merlin was not expressed in the retina, optic nerve, or iris lesions. These results suggest that inactivation of the NF2 gene is associated with the formation of a variety of retinal and optic nerve lesions in NF2 patients. Copyright 2002 John Wiley & Sons, Ltd.

3
UI - 11934389
AU - Fang LJ; Li W; Chalhoub N; Feingold J; Ortenberg J; Thirion JP
TI - Linkage disequilibrium and founder effect analysis of the NF1 gene in French Canadians from the Quebec population.
SO - Ann Genet 2002 Jan-Mar;45(1):39-44
AD - Departement de microbiologie et d'infectiologie, faculte de medecine, Universite de Sherbrooke, Sherbrooke, PQ J1H 5N4, Canada.
We genotyped 19 neurofibromatosis type 1 (NF1) families from French Canadians of the Quebec population with four intragenic microsatellites (IVS26-2.3, IVS27AC28.4, IVS27AC33.1, and IVS38GT53.0). Linkage analysis of the four microsatellite markers among the 19 NF1 families indicates that the four microsatellites are strongly linked with NF1 disease (LOD = 2.76-3.64). The four markers are associated (P = 0-0.077) except marker pair IVS26-2.3/IVS27AC33.1 (P = 0.18 or 0.17). However, perhaps due to the high mutation rate of the NF1 gene, no founder effect for NF1 was detected in the Quebec French Canadians.

4
UI - 12190883
AU - Pacheco TR; Bellus GA; Oreskovich NM; Talbert J; Old W; Fain PR
TI - Exclusion of candidate genes and loci for multiple lentigines syndrome.
SO - J Invest Dermatol 2002 Aug;119(2):535-8

5
UI - 12132297
AU - Petter G; Rytter M; Haustein UF
TI - [Multiple lentigines (LEOPARD) syndrome. Case reports and review of the literature]
SO - Hautarzt 2002 Jun;53(6):403-8
AD - Universitat Leipzig, Klinik und Poliklinik fur Hautkrankheiten, Liebigstrasse 21, 04103 Leipzig.
The rarely occurring multiple lentigines (LEOPARD) syndrome represents a complex of skin, heart, skeleton and other malformations and is described in a 36-year-old male and his 9-year-old daughter. With the occurrence of multiple lentigines, the diagnostic search for further malformations should always be undertaken. Its differential diagnosis and its pathogenetic and clinical aspects are discussed in this paper.

6
UI - 12130630
AU - Gautreau A; Manent J; Fievet B; Louvard D; Giovannini M; Arpin M
TI - Mutant products of the NF2 tumor suppressor gene are degraded by the ubiquitin-proteasome pathway.
SO - J Biol Chem 2002 Aug 30;277(35):31279-82
AD - UMR144 CNRS/Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
Neurofibromatosis type 2 (NF2), a syndrome associated with multiple tumors of the nervous system, mostly schwannomas, is caused by mutations in the NF2 tumor suppressor gene that encodes schwannomin (Sch). Here we examined NF2 pathogenetic mutations that result in misfolding of the FERM domain. We found that these mutant forms of Sch were efficiently degraded by the ubiquitin-proteasome pathway. In transfected cells, Sch Delta F118 was 3-fold more efficiently degraded than the related molecule ezrin bearing the equivalent mutation. In heterozygous Nf2 knock-out mouse fibroblasts, endogenous mutant Sch Delta 81-121, but not wild type Sch, was also degraded by proteasomes. We further show that this degradation pathway is functional in primary Schwann cells. We analyzed Sch Delta 39-121 expressed in a transgenic mouse model of NF2 and found that Sch Delta 39-121, but not the endogenous wild type Sch, was unstable due to proteasome-mediated degradation. Altogether these results suggest that degradation of mutant Sch mediated by the ubiquitin-proteasome pathway is a physiopathological pathway contributing to the loss of Sch function in NF2 patients.

7
UI - 12111361
AU - Hagel C; Lindenau M; Lamszus K; Kluwe L; Stavrou D; Mautner VF
TI - Polyneuropathy in neurofibromatosis 2: clinical findings, molecular genetics and neuropathological alterations in sural nerve biopsy specimens.
SO - Acta Neuropathol (Berl) 2002 Aug;104(2):179-87
AD - Department of Neuropathology, University Clinic Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. hagel@uke.uni-hamburg.de
Neurofibromatosis 2 (NF2) is an autosomal dominant disease characterised by development of tumours in the central and peripheral nervous system. Some NF2 patients develop acro-distal sensory motor polyneuropathy that can hardly be explained by the tumour burden alone. In the present study eight sural nerve biopsy specimens from seven NF2 patients suffering from polyneuropathy were investigated, data including clinical course of the disease, electrophysiological findings, teased fibre preparations, histopathological, morphometric, immunohistochemical, electron microscopic and molecular genetic findings. All patients suffered from distal symmetric reflex loss, symmetrical stocking-like hypalgesia and hypesthesia and loss of vibration sense later followed by a slowly progressive distal muscle atrophy and paresis. Sural nerve biopsy specimens revealed a pathological reduction of nerve fibre density correlating with age. In addition, diffuse proliferation of Schwann cells was observed in five of eight biopsies, and small endoneurial tumourlets of schwannomas and perineuriomas were found in two of eight and one of eight samples, respectively. Ki-67 labelling revealed a slight endoneurial proliferative activity in three cases. Schwann cell onion bulbs with or without central myelinated axon were seen in two cases. The findings suggest an axonopathy of multifactorial origin resulting not only from gross tumour growth but, in addition, from small endoneurial tumourlets, diffuse proliferation of Schwann cells and proliferation of perineurial cells.

8
UI - 12213770
AU - Roy-Engel AM; Salem AH; Oyeniran OO; Deininger L; Hedges DJ; Kilroy GE;
TI - Batzer MA; Deininger PL Active Alu element "A-tails": size does matter.
SO - Genome Res 2002 Sep;12(9):1333-44
AD - Tulane Cancer Center, SL-66, Department of Environmental Health Sciences, Tulane University-Health Sciences Center, New Orleans, Louisiana 70112, USA.
Long and short interspersed elements (LINEs and SINEs) are retroelements that make up almost half of the human genome. L1 and Alu represent the most prolific human LINE and SINE families, respectively. Only a few Alu elements are able to retropose, and the factors determining their retroposition capacity are poorly understood. The data presented in this paper indicate that the length of Alu "A-tails" is one of the principal factors in determining the retropositional capability of an Alu element. The A stretches of the Alu subfamilies analyzed, both old (Alu S and J) and young (Ya5), had a Poisson distribution of A-tail lengths with a mean size of 21 and 26, respectively. In contrast, the A-tails of very recent Alu insertions (disease causing) were all between 40 and 97 bp in length. The L1 elements analyzed displayed a similar tendency, in which the "disease"-associated elements have much longer A-tails (mean of 77) than do the elements even from the young Ta subfamily (mean of 41). Analysis of the draft sequence of the human genome showed that only about 1000 of the over one million Alu elements have tails of 40 or more adenosine residues in length. The presence of these long A stretches shows a strong bias toward the actively amplifying subfamilies, consistent with their playing a major role in the amplification process. Evaluation of the 19 Alu elements retrieved from the draft sequence of the human genome that are identical to the Alu Ya5a2 insert in the NF1 gene showed that only five have tails with 40 or more adenosine residues. Sequence analysis of the loci with the Alu elements containing the longest A-tails (7 of the 19) from the genomes of the NF1 patient and the father revealed that there are at least two loci with A-tails long enough to serve as source elements within our model. Analysis of the A-tail lengths of 12 Ya5a2 elements in diverse human population groups showed substantial variability in both the Alu A-tail length and sequence homogeneity. On the basis of these observations, a model is presented for the role of A-tail length in determining which Alu elements are active.

9
UI - 10726824
AU - North KN
TI - Clinical aspects of neurofibromatosis 1.
SO - Eur J Paediatr Neurol 1998;2(5):223-31
AD - The Royal Alexandra Hospital for Children, Department of Paediatrics and Child Health, University of Sydney, Australia.

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