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- Fogh, Isabella, et al.
(författare)
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A genome-wide association meta-analysis identifies a novel locus at 17q11.2 associated with sporadic amyotrophic lateral sclerosis
- 2014
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Ingår i: Human Molecular Genetics. - Oxford : Oxford University Press. - 0964-6906 .- 1460-2083. ; 23:8, s. 2220-2231
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Tidskriftsartikel (refereegranskat)abstract
- Identification of mutations at familial loci for amyotrophic lateral sclerosis (ALS) has provided novel insights into the aetiology of this rapidly progressing fatal neurodegenerative disease. However, genome-wide association studies (GWAS) of the more common (90) sporadic form have been less successful with the exception of the replicated locus at 9p21.2. To identify new loci associated with disease susceptibility, we have established the largest association study in ALS to date and undertaken a GWAS meta-analytical study combining 3959 newly genotyped Italian individuals (1982 cases and 1977 controls) collected by SLAGEN (Italian Consortium for the Genetics of ALS) together with samples from Netherlands, USA, UK, Sweden, Belgium, France, Ireland and Italy collected by ALSGEN (the International Consortium on Amyotrophic Lateral Sclerosis Genetics). We analysed a total of 13 225 individuals, 6100 cases and 7125 controls for almost 7 million single-nucleotide polymorphisms (SNPs). We identified a novel locus with genome-wide significance at 17q11.2 (rs34517613 with P 1.11 10(8); OR 0.82) that was validated when combined with genotype data from a replication cohort (P 8.62 10(9); OR 0.833) of 4656 individuals. Furthermore, we confirmed the previously reported association at 9p21.2 (rs3849943 with P 7.69 10(9); OR 1.16). Finally, we estimated the contribution of common variation to heritability of sporadic ALS as 12 using a linear mixed model accounting for all SNPs. Our results provide an insight into the genetic structure of sporadic ALS, confirming that common variation contributes to risk and that sufficiently powered studies can identify novel susceptibility loci.
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| 2. |
- Smith, Bradley N., et al.
(författare)
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The C9ORF72 expansion mutation is a common cause of ALS+/-FTD in Europe and has a single founder
- 2013
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Ingår i: European Journal of Human Genetics. - London : Nature Publishing Group. - 1018-4813 .- 1476-5438. ; 21:1, s. 102-108
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Tidskriftsartikel (refereegranskat)abstract
- A massive hexanucleotide repeat expansion mutation (HREM) in C9ORF72 has recently been linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we describe the frequency, origin and stability of this mutation in ALS+/-FTD from five European cohorts (total n = 1347). Single-nucleotide polymorphisms defining the risk haplotype in linked kindreds were genotyped in cases (n = 434) and controls (n = 856). Haplotypes were analysed using PLINK and aged using DMLE+. In a London clinic cohort, the HREM was the most common mutation in familial ALS+/-FTD: C9ORF72 29/112 (26%), SOD1 27/112 (24%), TARDBP 1/112 (1%) and FUS 4/112 (4%) and detected in 13/216 (6%) of unselected sporadic ALS cases but was rare in controls (3/856, 0.3%). HREM prevalence was high for familial ALS+/-FTD throughout Europe: Belgium 19/22 (86%), Sweden 30/41 (73%), the Netherlands 10/27 (37%) and Italy 4/20 (20%). The HREM did not affect the age at onset or survival of ALS patients. Haplotype analysis identified a common founder in all 137 HREM carriers that arose around 6300 years ago. The haplotype from which the HREM arose is intrinsically unstable with an increased number of repeats (average 8, compared with 2 for controls, P<10(-8)). We conclude that the HREM has a single founder and is the most common mutation in familial and sporadic ALS in Europe.
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| 6. |
- Ygland, E., et al.
(författare)
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Friedreich's ataxia in patients with FXN p.R165P point mutation
- 2012
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Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101. ; 19:Suppl 1, s. 727-727
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Konferensbidrag (refereegranskat)abstract
- Introduction: Friedreich's ataxia (FRDA) is a hereditary disorder with progressive postural ataxia, dysarthria, neuropathy, muscle weakness and cardiomyopathy. Lack or malfunction of the protein frataxin due to mutations in the frataxin gene (FXN) is the cause of the disease. Most patients are homozygous for GAA trinucleotide expansions in FXN but disease can also be caused by heterozygosity for the expansion and a point mutation. Milder disease has been reported for some FRDA patients with missense mutations. Methods: We describe 3 FRDA patients, not previously reported, with the FXN p.R165P missense mutation and compared clinical features with 6 homozygous GAA expansion carriers. Patients were interviewed, examined clinically and assessed with FRDA rating scale (FARS). Blood was collected for reanalysis of GAA expansion length and for frataxin measurements. Results: Compared to patients homozygous for FXN GAA expansion, p.R165P mutation carriers had more wellpreserved upper limb function and deep tendon reflexes, considerably milder dysarthria, but possibly an increased occurrence of psychosis. p.R165P patients were more independent in activities of daily living, especially when correlated to disease duration. We found no difference in other clinical aspects or in GAA expansion length. One patient had severe FRDA symptoms and comorbid hemochromatosis, whereas his sibling without hemochromatosis had much milder disease. Refined analysis of GAA expansion length and frataxin levels are in progress. Conclusion: p.R165P FRDA patients appear to progress to a less disabling disease state than typical FRDA. We suggest additive effects of comorbid FRDA and hemochromatosis, due to synergistic abnormalities in iron metabolism.
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