| 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. |
- Akimoto, Chizuru, et al.
(författare)
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No GGGGCC-hexanucleotide repeat expansion in C9ORF72 in parkinsonism patients in Sweden
- 2013
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Ingår i: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. - : Informa Healthcare. - 2167-8421 .- 2167-9223. ; 14:1, s. 26-29
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Tidskriftsartikel (refereegranskat)abstract
- An intronic GGGGCC-hexanucleotide repeat expansion in C9ORF72 was recently identified as a major cause of amyotrophic lateral sclerosis and frontotemporal dementia. Some amyotrophic lateral sclerosis patients have signs of parkinsonism, and many parkinsonism patients develop dementia. In this study we examined if the hexanucleotide repeat expansion was present in parkinsonism patients, to clarify if there could be a relationship between the repeat expansion and disease. We studied the size of the hexanucleotide repeat expansion in a well defined population-based cohort of 135 Parkinson's disease patients and 39 patients with atypical parkinsonism and compared with 645 Swedish control subjects. We found no correlation between Parkinson's disease or atypical parkinsonism and the size of the GGGGCC repeat expansion in C9ORF72. In conclusion, this GGGGCC-repeat expansion in C9ORF72 is not a cause of parkinsonism in the Swedish population.
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| 3. |
- Birve, Anna, et al.
(författare)
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A novel SOD1 splice site mutation associated with familial ALS revealed by SOD activity analysis
- 2010
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 19:21, s. 4201-4206
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Tidskriftsartikel (refereegranskat)abstract
- More than 145 mutations have been found in the gene CuZn-Superoxide dismutase (SOD1) in patients with amyotrophic lateral sclerosis (ALS). The vast majority are easily detected nucleotide mutations in the coding region. In a patient from a Swiss ALS family with half-normal erythrocyte SOD1 activity, exon flanking sequence analysis revealed a novel thymine to guanine mutation 7 bp upstream of exon 4 (c.240-7T>G). The results of splicing algorithm analyses were ambiguous, but five out of seven analysis tools suggested a potential novel splice site that would add six new base pairs to the mRNA. If translated, this mRNA would insert Ser and Ile between Glu78 and Arg79 in the SOD1 protein. In fibroblasts from the patient, the predicted mutant transcript and the mutant protein were both highly expressed, and despite the location of the insertion into the metal ion-binding loop IV, the SOD1 activity appeared high. In erythrocytes, which lack protein synthesis and are old compared with cultured fibroblasts, both SOD1 protein and enzymic activity was 50% of controls. Thus, the usage of the novel splice site is near 100%, and the mutant SOD1 shows the reduced stability typical of ALS-associated mutant SOD1s. The findings suggests that this novel intronic mutation is causing the disease and highlights the importance of wide exon-flanking sequencing and transcript analysis combined with erythrocyte SOD1 activity analysis in comprehensive search for SOD1 mutations in ALS. We find that there are potentially more SOD1 mutations than previously reported.
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| 4. |
- Blauw, Hylke M, et al.
(författare)
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A large genome scan for rare CNVs in amyotrophic lateral sclerosis
- 2010
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Ingår i: Human Molecular Genetics. - : Oxford Journals. - 0964-6906 .- 1460-2083. ; 19:20, s. 4091-4099
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease selectively affecting motor neurons in the brain and spinal cord. Recent genome-wide association studies (GWASs) have identified several common variants which increase disease susceptibility. In contrast, rare copy-number variants (CNVs), which have been associated with several neuropsychiatric traits, have not been studied for ALS in well-powered study populations. To examine the role of rare CNVs in ALS susceptibility, we conducted a CNV association study including over 19,000 individuals. In a genome-wide screen of 1875 cases and 8731 controls, we did not find evidence for a difference in global CNV burden between cases and controls. In our association analyses, we identified two loci that met our criteria for follow-up: the DPP6 locus (OR = 3.59, P = 6.6 × 10(-3)), which has already been implicated in ALS pathogenesis, and the 15q11.2 locus, containing NIPA1 (OR = 12.46, P = 9.3 × 10(-5)), the gene causing hereditary spastic paraparesis type 6 (HSP 6). We tested these loci in a replication cohort of 2559 cases and 5887 controls. Again, results were suggestive of association, but did not meet our criteria for independent replication: DPP6 locus: OR = 1.92, P = 0.097, pooled results: OR = 2.64, P = 1.4 × 10(-3); NIPA1: OR = 3.23, P = 0.041, pooled results: OR = 6.20, P = 2.2 × 10(-5)). Our results highlight DPP6 and NIPA1 as candidates for more in-depth studies. Unlike other complex neurological and psychiatric traits, rare CNVs with high effect size do not play a major role in ALS pathogenesis.
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| 5. |
- Bogaert, Elke, et al.
(författare)
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Polymorphisms in the GluR2 gene are not associated with amyotrophic lateral sclerosis
- 2012
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 33:2, s. 418-420
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Tidskriftsartikel (refereegranskat)abstract
- Excitotoxicity is thought to play a pathogenic role in amyotrophic lateral sclerosis (ALS). Excitotoxic motor neuron death is mediated through the Ca(2+)-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type of glutamate receptors and Ca(2+) permeability is determined by the GluR2 subunit. We investigated whether polymorphisms or mutations in the GluR2 gene (GRIA2) predispose patients to ALS. Upon sequencing 24 patients and 24 controls no nonsynonymous coding variants were observed but 24 polymorphisms were identified, 9 of which were novel. In a screening set of 310 Belgian ALS cases and 794 healthy controls and a replication set of 3157 cases and 5397 controls from 6 additional populations no association with susceptibility, age at onset, or disease duration was observed. We conclude that polymorphisms in the GluR2 gene (GRIA2) are not a major contributory factor in the pathogenesis of ALS.
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| 6. |
- Brotherton, Terrell, et al.
(författare)
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A novel ALS SOD1 C6S mutation with implications for aggregation related toxicity and genetic counseling
- 2011
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Ingår i: Amyotrophic Lateral Sclerosis and other Motor Neuron Disorders. - : Informa UK Limited. - 1466-0822 .- 1743-4483. ; 12:3, s. 215-219
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Tidskriftsartikel (refereegranskat)abstract
- In this report we describe an ALS family with a novel missense SOD1 mutation with substitution of serine for cysteine at the sixth amino acid (C6S). This mutation has interesting implications for the role of disulfides in causing disease. After identification of the ALS proband, we examined 17 members of an extended family and performed DNA mutation analysis on 21 family members. The level and activity of SOD1 in C6S carriers and wild-type family members was analyzed in erythrocytes. We found that the C6S mutation results in disease with an autosomal dominant mode of inheritance and markedly reduced penetrance. The S6 mutated protein demonstrates high stability relative to the C6 wild-type protein. The specific dismutation activity of S6 SOD1 is normal. In conclusion, C6S is a novel FALS associated mutation with reduced disease penetrance, long survival time and a phenotype very different from the other SOD1 mutations reported in codon C6. This mutation may provide insight into the role of SOD1 structural changes in disease.
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| 7. |
- Eschbach, Judith, et al.
(författare)
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PGC-1 is a male-specific disease modifier of human and experimental amyotrophic lateral sclerosis
- 2013
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 22:17, s. 3477-3484
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a devastating, adult-onset neurodegenerative disorder of the upper and lower motor systems. It leads to paresis, muscle wasting and inevitably to death, typically within 35 years. However, disease onset and survival vary considerably ranging in extreme cases from a few months to several decades. The genetic and environmental factors underlying this variability are of great interest as potential therapeutic targets. In ALS, men are affected more often and have an earlier age of onset than women. This gender difference is recapitulated in transgenic rodent models, but no underlying mechanism has been elucidated. Here we report that SNPs in the brain-specific promoter region of the transcriptional co-activator PGC-1, a master regulator of metabolism, modulate age of onset and survival in two large and independent ALS populations and this occurs in a strictly male-specific manner. In complementary animal studies, we show that deficiency of full-length (FL) Pgc-1 leads to a significantly earlier age of onset and a borderline shortened survival in male, but not in female ALS-transgenic mice. In the animal model, FL Pgc-1-loss is associated with reduced mRNA levels of the trophic factor Vegf-A in males, but not in females. In summary, we indentify PGC-1 as a novel and clinically relevant disease modifier of human and experimental ALS and report a sex-dependent effect of PGC-1 in this neurodegenerative disorder.
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| 8. |
- Graffmo, Karin S., et al.
(författare)
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Expression of wild-type human superoxide dismutase-1 in mice causes amyotrophic lateral sclerosis
- 2013
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 22:1, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- A common cause of amyotrophic lateral sclerosis (ALS) is mutations in the gene encoding superoxide dismutase-1. There is evolving circumstantial evidence that the wild-type protein can also be neurotoxic and that it may more generally be involved in the pathogenesis of ALS. To test this proposition more directly, we generated mice that express wild-type human superoxide dismutase-1 at a rate close to that of mutant superoxide dismutase-1 in the commonly studied G93A transgenic model. These mice developed an ALS-like syndrome and became terminally ill after around 370 days. The loss of spinal ventral neurons was similar to that in the G93A and other mutant superoxide dismutase-1 models, and large amounts of aggregated superoxide dismutase-1 were found in spinal cords, but also in the brain. The findings show that wild-type human superoxide dismutase-1 has the ability to cause ALS in mice, and they support the hypothesis of a more general involvement of the protein in the disease in humans.
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| 9. |
- Hugosson, Fredrik, et al.
(författare)
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The Drosophila Midkine/Pleiotrophin Homologues Miple1 and Miple2 Affect Adult Lifespan but Are Dispensable for Alk Signaling during Embryonic Gut Formation
- 2014
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Midkine (MDK) and Pleiotrophin (PTN) are small heparin-binding cytokines with closely related structures. The Drosophila genome harbours two genes encoding members of the MDK/PTN family of proteins, known as miple1 and miple2. We have investigated the role of Miple proteins in vivo, in particular with regard to their proposed role as ligands for the Alk receptor tyrosine kinase (RTK). Here we show that Miple proteins are neither required to drive Alk signaling during Drosophila embryogenesis, nor are they essential for development in the fruit fly. Additionally we show that neither MDK nor PTN can activate hALK in vivo when ectopically co-expressed in the fly. In conclusion, our data suggest that Alk is not activated by MDK/PTN related growth factors Miple1 and Miple 2 in vivo.
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| 10. |
- 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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