| 1. |
- Akimoto, Chizuru, et al.
(författare)
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A blinded international study on the reliability of genetic testing for GGGGCC-repeat expansions in C9orf72 reveals marked differences in results among 14 laboratories
- 2014
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 51:6, s. 419-424
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Tidskriftsartikel (refereegranskat)abstract
- Background The GGGGCC-repeat expansion in C9orf72 is the most frequent mutation found in patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Most of the studies on C9orf72 have relied on repeat-primed PCR (RP-PCR) methods for detection of the expansions. To investigate the inherent limitations of this technique, we compared methods and results of 14 laboratories. Methods The 14 laboratories genotyped DNA from 78 individuals (diagnosed with ALS or FTD) in a blinded fashion. Eleven laboratories used a combination of amplicon-length analysis and RP-PCR, whereas three laboratories used RP-PCR alone; Southern blotting techniques were used as a reference. Results Using PCR-based techniques, 5 of the 14 laboratories got results in full accordance with the Southern blotting results. Only 50 of the 78 DNA samples got the same genotype result in all 14 laboratories. There was a high degree of false positive and false negative results, and at least one sample could not be genotyped at all in 9 of the 14 laboratories. The mean sensitivity of a combination of amplicon-length analysis and RP-PCR was 95.0% (73.9-100%), and the mean specificity was 98.0% (87.5-100%). Overall, a sensitivity and specificity of more than 95% was observed in only seven laboratories. Conclusions Because of the wide range seen in genotyping results, we recommend using a combination of amplicon-length analysis and RP-PCR as a minimum in a research setting. We propose that Southern blotting techniques should be the gold standard, and be made obligatory in a clinical diagnostic setting.
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| 2. |
- Ingre, Caroline, 1977-, et al.
(författare)
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A novel phosphorylation site mutation in profilin 1 revealed in a large screen of US, Nordic and German amyotrophic lateral sclerosis/frontotemporal dementia cohorts
- 2013
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Ingår i: Neurobiology of Aging. - New York : Elsevier. - 0197-4580 .- 1558-1497. ; 34:6
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Tidskriftsartikel (refereegranskat)abstract
- Profilin 1 is a central regulator of actin dynamics. Mutations in the gene profilin 1 (PFN1) have veryrecently been shown to be the cause of a subgroup of amyotrophic lateral sclerosis (ALS). Here, weperformed a large screen of US, Nordic, and German familial and sporadic ALS and frontotemporaldementia (FTLD) patients for PFN1 mutations to get further insight into the spectrum and pathogenicrelevance of this gene for the complete ALS/FTLD continuum. Four hundred twelve familial and 260sporadic ALS cases and 16 ALS/FTLD cases from Germany, the Nordic countries, and the United Stateswere screened for PFN1 mutations. Phenotypes of patients carrying PFN1 mutations were studied. Ina German ALS family we identified the novel heterozygous PFN1 mutation p.Thr109Met, which wasabsent in controls. This novel mutation abrogates a phosphorylation site in profilin 1. The recentlydescribed p.Gln117Gly sequence variant was found in another familial ALS patient from the United States.The ALS patients with mutations in PFN1 displayed spinal onset motor neuron disease without overtcognitive involvement. PFN1 mutations were absent in patients with motor neuron disease anddementia, and in patients with only FTLD. We provide further evidence that PFN1 mutations can causeALS as a Mendelian dominant trait. Patients carrying PFN1 mutations reported so far represent the“classic” ALS end of the ALS-FTLD spectrum. The novel p.Thr109Met mutation provides additional proofof-principle that mutant proteins involved in the regulation of cytoskeletal dynamics can cause motorneuron degeneration. Moreover, this new mutation suggests that fine-tuning of actin polymerization byphosphorylation of profilin 1 might be necessary for motor neuron survival.
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| 3. |
- Weishaupt, Jochen H, et al.
(författare)
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A novel optineurin truncating mutation and three glaucoma-associated missense variants in patients with familial amyotrophic lateral sclerosis in Germany
- 2013
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:5, s. 1516.e9-1516.e15
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in the optineurin (OPTN) gene have been associated with normal tension glaucoma and with amyotrophic lateral sclerosis (ALS). Here, we screened German familial ALS cases for OPTN mutations to gain additional insight into the spectrum and pathogenic relevance of this gene for ALS. One hundred familial German ALS cases and 148 control subjects were screened for OPTN mutations by sequence analysis of the complete OPTN coding sequence, and phenotypes of OPTN mutant patients were described. We identified a novel heterozygous truncating OPTN mutation p.Lys440Asnfs*8 in 1 ALS family with an aggressive ALS disease phenotype. This mutation abolishes protein domains crucial for nuclear factor kappa B signaling. Moreover, we detected 3 different nonsynonymous sequence variants, which have been described previously as risk factors for primary retinal ganglion cell degeneration in normal tension glaucoma. Two of them were detected on the same allele in a family that also carries a p.Asn352Ser disease mutation in the ALS gene TARDBP. All OPTN mutant patients presented with typical spinal onset ALS. Taken together, we detected a novel truncating OPTN mutation associated with an aggressive form of ALS and confirmed that OPTN mutations are a rare cause of ALS. In addition our data suggest that in some cases plausibly more than 1 mutation in OPTN or another ALS gene might be needed to cause ALS. Finally, our findings show that motoneurons and retinal ganglion cells, which are both projecting central nervous system neurons, might share common susceptibility factors. (C) 2013 Elsevier Inc. All rights reserved.
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