| 1. |
- Sawcer, Stephen, et al.
(författare)
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Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
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Tidskriftsartikel (refereegranskat)abstract
- Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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| 2. |
- Beecham, Ashley H, et al.
(författare)
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Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis.
- 2013
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:11, s. 1353-60
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Tidskriftsartikel (refereegranskat)abstract
- Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.
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| 3. |
- Langefeld, Carl D., et al.
(författare)
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Transancestral mapping and genetic load in systemic lupus erythematosus
- 2017
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune disease with marked gender and ethnic disparities. We report a large transancestral association study of SLE using Immunochip genotype data from 27,574 individuals of European (EA), African (AA) and Hispanic Amerindian (HA) ancestry. We identify 58 distinct non-HLA regions in EA, 9 in AA and 16 in HA (similar to 50% of these regions have multiple independent associations); these include 24 novel SLE regions (P < 5 x 10(-8)), refined association signals in established regions, extended associations to additional ancestries, and a disentangled complex HLA multigenic effect. The risk allele count (genetic load) exhibits an accelerating pattern of SLE risk, leading us to posit a cumulative hit hypothesis for autoimmune disease. Comparing results across the three ancestries identifies both ancestry-dependent and ancestry-independent contributions to SLE risk. Our results are consistent with the unique and complex histories of the populations sampled, and collectively help clarify the genetic architecture and ethnic disparities in SLE.
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| 4. |
- Nicolas, Aude, et al.
(författare)
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Genome-wide Analyses Identify KIF5A as a Novel ALS Gene
- 2018
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Ingår i: Neuron. - : Cell Press. - 0896-6273 .- 1097-4199. ; 97:6, s. 1268-1283.e6
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Tidskriftsartikel (refereegranskat)abstract
- To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.
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| 5. |
- Castillejo-Lopez, Casimiro, et al.
(författare)
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Genetic and physical interaction of the B-cell systemic lupus erythematosus-associated genes BANK1 and BLK
- 2012
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 71:1, s. 136-142
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesAltered signalling in B cells is a predominant feature of systemic lupus erythematosus (SLE). The genes BANK1 and BLK were recently described as associated with SLE. BANK1 codes for a B-cell-specific cytoplasmic protein involved in B-cell receptor signalling and BLK codes for an Src tyrosine kinase with important roles in B-cell development. To characterise the role of BANK1 and BLK in SLE, a genetic interaction analysis was performed hypothesising that genetic interactions could reveal functional pathways relevant to disease pathogenesis.MethodsThe GPAT16 method was used to analyse the gene-gene interactions of BANK1 and BLK. Confocal microscopy was used to investigate co-localisation, and immunoprecipitation was used to verify the physical interaction of BANK1 and BLK.ResultsEpistatic interactions between BANK1 and BLK polymorphisms associated with SLE were observed in a discovery set of 279 patients and 515 controls from northern Europe. A meta-analysis with 4399 European individuals confirmed the genetic interactions between BANK1 and BLK. As BANK1 was identified as a binding partner of the Src tyrosine kinase LYN, the possibility that BANK1 and BLK could also show a protein-protein interaction was tested. The co-immunoprecipitation and co-localisation of BLK and BANK1 were demonstrated. In a Daudi cell line and primary naive B cells endogenous binding was enhanced upon B-cell receptor stimulation using anti-IgM antibodies.ConclusionsThis study shows a genetic interaction between BANK1 and BLK, and demonstrates that these molecules interact physically. The results have important consequences for the understanding of SLE and other autoimmune diseases and identify a potential new signalling pathway.
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| 6. |
- Johansson, Anders, et al.
(författare)
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Spectroscopic Measurement of Cartilage Thickness in Arthroscopy: Ex Vivo Validation in Human Knee Condyles
- 2012
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Ingår i: Arthroscopy. - : WB Saunders. - 0749-8063 .- 1526-3231. ; 28:10, s. 1513-1523
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the accuracy of articular cartilage thickness measurement when implementing a new technology based on spectroscopic measurement into an arthroscopic camera. Methods: Cartilage thickness was studied by ex vivo arthroscopy at a number of sites (N = 113) in human knee joint osteoarthritic femoral condyles and tibial plateaus, removed from 7 patients undergoing total knee replacement. The arthroscopic image spectral data at each site were used to estimate cartilage thickness. Arthroscopically derived thickness values were compared with reference cartilage thickness as measured by 3 different methods: needle penetration, spiral computed tomography scanning, and geometric measurement after sample slicing. Results: The lowest mean error (0.28 to 0.30 mm) in the regression between arthroscopic and reference cartilage thickness was seen for reference cartilage thickness less than 1.5 mm. Corresponding values for cartilage thickness less than 2.0 and 2.5 mm were 0.32 to 0.40 mm and 0.37 to 0.47 mm, respectively. Cartilage thickness images-created by pixel-by-pixel regression model calculations applied to the arthroscopic images-were derived to demonstrate the clinical use of a camera implementation. Conclusions: On the basis of this investigation on osteoarthritic material, when one is implementing the spectroscopic method for estimating cartilage thickness into an arthroscopic camera, errors in the range of 0.28 to 0.30 mm are expected. This implementation does not, however, influence the fact that the spectral method performs less well in the cartilage thickness region from 1.5 to 2.5 mm and cannot assess cartilage thicker than 2.5 mm. Clinical Relevance: Imaging cartilage thickness directly in the arthroscopic camera video stream could serve as an interesting image tool for in vivo cartilage quality assessment, in connection with cartilage diagnosis, repair, and follow-up.
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