Showing papers by "Frank Baas published in 2006"

Familial amyotrophic lateral sclerosis with frontotemporal dementia is linked to a locus on chromosome 9p13.2–21.3

Abstract: Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are both relentlessly progressive and ultimately fatal neurological disorders. ALS is familial in approximately 10% of cases and FTD in approximately 30%. Inheritance is usually autosomal dominant with variable penetrance. Phenotypic overlap between ALS and FTD can occur within the same kindred. Mutations in copper/zinc superoxide dismutase 1 (SOD1) are found in approximately 20% of familial and approximately 3% of sporadic ALS cases but are not associated with dementia. Mutations in microtubule associated protein tau (MAPT) are detected in approximately 30% of familial FTD kindreds. Dominant ALS with FTD has previously been linked to 9q21 and pure ALS to loci on 16q21, 18q21, 20p13. Here we report the results of a genome-wide linkage study in a large ALS and FTD kindred using Affymetrix 10K GeneChip microarrays. Linkage analysis of single nucleotide polymorphism (SNP) data identified consistently positive log of the odds (LOD) scores across chromosome 9p (maximal LOD score of 2.4). Fine mapping the region with microsatellite markers generated a maximal multipoint LOD score of 3.02 (theta = 0) at D9S1878. Recombination narrowed the conserved haplotype to 12 cM (11 Mb) at 9p13.2-21.3 (flanking markers D9S2154 and D9S1874). Bioinformatic analysis of the region has identified 103 known genes.

Axonal neuropathy with optic atrophy is caused by mutations in mitofusin 2.

Abstract: Objective Charcot-Marie-Tooth (CMT) neuropathy with visual impairment due to optic atrophy has been designated as hereditary motor and sensory neuropathy type VI (HMSN VI). Reports of affected families have indicated autosomal dominant and recessive forms, but the genetic cause of this disease has remained elusive. Methods Here, we describe six HMSN VI families with a subacute onset of optic atrophy and subsequent slow recovery of visual acuity in 60% of the patients. Detailed clinical and genetic studies were performed. Results In each pedigree, we identified a unique mutation in the gene mitofusin 2 (MFN2). In three families, the MFN2 mutation occurred de novo; in two families the mutation was subsequently transmitted from father to son indicating autosomal dominant inheritance. Interpretation MFN2 is a mitochondrial membrane protein that was recently reported to cause axonal CMT type 2A. It is intriguing that MFN2 shows functional overlap with optic atrophy 1 (OPA1), the protein underlying the most common form of autosomal dominant optic atrophy, and mitochondrial encoded oxidative phosphorylation components as seen in Leber's hereditary optic atrophy. We conclude that autosomal dominant HMSN VI is caused by mutations in MFN2, emphasizing the important role of mitochondrial function for both optic atrophies and peripheral neuropathies. Ann Neurol 2006;59:276–281

Rna antagonist compounds for the modulation of p21 ras expression

Abstract: Oligonucleotides directed against the p21 Ras genes are provided for modulating the expression of p21 Ras. The compositions comprise oligonucleotides, particularly antisense oligonucleotides, targeted to nucleic acids encoding Ha-ras, Ki-ras and N-ras. Methods of using these compounds for modulation of p21 Ras expression and for the treatment of diseases associated with either overexpression of p21 Ras, expression of mutated p21 Ras or both are provided. Examples of diseases are cancer such as lung, breast, colon, prostate, pancreas, lung, liver, thyroid, kidney, brain, testes, stomach, intestine, bowel, spinal cord, sinuses, bladder, urinary tract or ovaries cancers. The oligonucleotides may be composed of deoxyribonucleotides or a nucleic acid analogue such as for example locked nucleic acid or a combination thereof.

Charcot-marie-tooth disease due to a de novo mutation of the RAB7 gene

Abstract: We report a 32-year-old patient with Charcot-Marie-Tooth (CMT2B) including foot ulcerations. Genetic analysis identified a de novo mutation in the small GTP-ase late endosomal RAB7 gene, consisting of a c.471G>C, p.Lys157Asn missense mutation. This observation strongly supports the hypothesis that RAB7 mutations are responsible for CMT2B.

OTX1 and OTX2 expression correlates with the clinicopathologic classification of medulloblastomas.

Abstract: OTX1 and OTX2 are transcription factors with an essential role in the development of the cerebellum. We previously described a high OTX2 expression in medulloblastoma. Here, we analyzed amplification and mRNA expression of OTX1 and OTX2 in a series of human medulloblastomas. In addition, OTX2 protein expression was analyzed on tissue arrays. The OTX2 gene was amplified in the medulloblastoma cell line D425 and mRNA and protein data showed expression in 114 of 152 medulloblastomas (75%), but not in postnatal cerebellum. Northern blot (n = 10) and reverse transcriptase-polymerase chain reaction (n = 45) analyses demonstrated that virtually all medulloblastomas expressed OTX1, OTX2, or both. OTX2 mRNA expression correlated with a classic medulloblastoma histology (29 of 34 cases), whereas expression of OTX1 mRNA only was correlated with a nodular/desmoplastic histology (9 of 11 cases). Immunohistochemical analysis of a series of classic medulloblastomas detected OTX2 protein expression in 83 of 107 (78%) cases. The OTX2-positive tumors of this series were preferentially localized in the vermis of the cerebellum, whereas OTX2-negative tumors more frequently occurred in the hemispheres of the cerebellum. In addition, OTX2-positive tumors were mainly found in children, but OTX2-negative tumors occurred in 2 patient groups: very young patients ( 20 years). Nodular/desmoplastic medulloblastomas are thought to arise from the external granular layer (EGL). However, it is unclear whether classic medulloblastomas also originate from the EGL or from the ventricular matrix. Analysis of human fetal brain showed OTX2 protein expression in a small number of presumptive neuronal precursor cells of the EGL, but not in precursor cells of the ventricular matrix. Combined with data from rodents, our results therefore suggest that both nodular/desmoplastic and at least part of the classic medulloblastomas originate from cells of the EGL, albeit from different regions.

Monitoring the T-Cell Receptor Repertoire at Single-Clone Resolution

Abstract: The adaptive immune system recognizes billions of unique antigens using highly variable T-cell receptors. The αβ T-cell receptor repertoire includes an estimated 106 different rearranged β chains per individual. This paper describes a novel micro-array based method that monitors the β chain repertoire with a resolution of a single T-cell clone. These T-arrays are quantitative and detect T-cell clones at a frequency of less than one T cell in a million, which is 2 logs more sensitive than spectratyping (immunoscope), the current standard in repertoire analysis. Using T-arrays we detected CMV-specific CD4+ and CD8+ T-cell clones that expanded early after viral antigen stimulation in vitro and in vivo. This approach will be useful in monitoring individual T-cell clones in diverse experimental settings, and in identification of T-cell clones associated with infectious disease, autoimmune disease and cancer.

Phenotype-genotype correlation in Dutch patients with myoclonus-dystonia

Abstract: The epsilon-sarcoglycan (SGCE) gene is an important cause of myoclonus-dystonia (M-D), although the majority of cases with an M-D phenotype test negative. Seven of 31 patients with the M-D phenotype carried a mutation in the SGCE gene. Positive family history and truncal myoclonus were independent prognostic factors. Early disease onset, onset with both myoclonus and dystonia, and axial dystonia were detected significantly more often in the mutation carriers.

Always around, never the same: pathways of amyloid beta induced neurodegeneration throughout the pathogenic cascade of Alzheimer's disease.

Abstract: There is an increasing amount of evidence showing the importance of intermediate aggregation species of amyloid beta (Abeta) in the pathogenic cascade of Alzheimer's disease (AD). Different Abeta assembly forms may mediate diverse toxic effects at different stages of the disease. Mouse models for AD suggest that intraneuronal accumulation of Abeta oligomers might be involved in AD pathogenesis at a very early stage of the disease. The detrimental effect of oligomeric Abeta on synaptic efficacy is suggested to be an early event in the pathogenic cascade. Also early neuronal responses as activation of the unfolded protein response are processes likely to be associated with the increased occurrence of oligomeric or low fibrillar Abeta in AD pathology. In later stages of AD pathology, the fibrillarity of Abeta increases, concomitantly with a neuroinflammatory response, followed by tau related neurofibrillary changes in end stage pathology. We will review recent findings in in vitro cell models, in vivo mouse models, and post mortem AD brain tissue in view of the effects of different Abeta peptide species on neurodegeneration during AD pathogenesis. Insight into the role of different Abeta species during AD pathogenesis is essential for the development of disease modifying drugs and therapeutical strategies.

Distal myoclonus and late onset in a large Dutch family with myoclonus–dystonia

Abstract: We report a large myoclonus-dystonia (M-D) pedigree with a two-base pair deletion in Exon 5 of the epsilon-sarcoglycan gene. Three individuals had onset after age 40 years. Distal myoclonus of the arms was present in all 20 symptomatic mutation carriers. These findings expand the known phenotype of M-D and require revision of the current diagnostic criteria. Five of 14 asymptomatic mutation carriers who inherited the mutation from their mother showed minimal axial dystonia, arguing against a maternal imprinting mechanism.

Comparison of CMT1A and CMT2: similarities and differences.

Abstract: To evaluate the clinical and electrophysiological similarities and differences between two large groups of patients with Charcot-Marie-Tooth disease, i.e. CMT1A and CMT2, we performed a post hoc comparison of clinical and electrophysiological data.

Late onset axonal Charcot-Marie-Tooth phenotype caused by a novel myelin protein zero mutation.

Abstract: A late onset axonal Charcot-Marie-Tooth phenotype is described, resulting from a novel mutation in the myelin protein zero (MPZ) gene. Comparative computer modelling of the three dimensional structure of the MPZ protein predicts that this mutation does not cause a significant structural change. The primary axonal disease process in these patients points to a function of MPZ in maintenance of the myelinated axons, apart from securing stability of the myelin layer.

Comparison of Schwann cell and sciatic nerve transcriptomes indicates that mouse is a valid model for the human peripheral nervous system

Abstract: High-throughput gene expression analyses of murine models of the peripheral nervous system (PNS), and its cellular components, have yielded enormous amounts of expression data of the PNS in various conditions. These data provided clues for future research directions to further decipher this complex organ in relation to acquired and inherited PNS diseases. Various studies addressing the validity of mouse models for human conditions in other tissues and cell types have indicated that in many cases the mouse model only poorly represents the human situation. To determine how well the mouse can serve as model to study the biological processes occurring in the PNS, we compared the gene expression profiles that we generated for mouse and human sciatic nerve and cultured Schwann cells derived thereof. A two-way analysis based on the differentially expressed genes between the sciatic nerve and the cultured Schwann cell, and which takes into account the differential expression between mouse and man, indicates that the human PNS is well represented by that of the mouse in terms of the "biological processes" ontology.

Composes antagonistes d'arn de modulation de l'expression de p21 ras

Abstract: L'invention concerne des oligonucleotides diriges contre les genes p21 Ras pour moduler l'expression de p21 Ras. Les compositions comprennent des oligonucleotides, en particulier des oligonucleotides antisens, cibles sur des acides nucleiques codant pour Ha-ras, Ki-ras et N-ras. L'invention concerne egalement des methodes d'utilisation de ces composes dans la modulation de l'expression de p21 Ras et dans le traitement des maladies associees a la surexpression de p21 Ras, l'expression de p21 Ras mutant, ou les deux. Des exemples de maladies sont le cancer, par exemple le cancer du poumon, du sein, du colon, de la prostate, du pancreas, du foie, de la thyroide, du rein, du cerveau, des testicules, de l'estomac, des intestins, de la moelle epiniere, des sinus, de la vessie, des voies urinaires ou des ovaires.