| 1. |
- Farias, Fabiana H. G., et al.
(författare)
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A rare regulatory variant in the MEF2D gene affects gene regulation and splicing and is associated with a SLE sub-phenotype in Swedish cohorts
- 2019
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 27, s. 432-441
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Tidskriftsartikel (refereegranskat)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune disorder with heterogeneous clinical presentation and complex etiology involving the interplay between genetic, epigenetic, environmental and hormonal factors. Many common SNPs identified by genome wide-association studies (GWAS) explain only a small part of the disease heritability suggesting the contribution from rare genetic variants, undetectable in GWAS, and complex epistatic interactions. Using targeted re-sequencing of coding and conserved regulatory regions within and around 215 candidate genes selected on the basis of their known role in autoimmunity and genes associated with canine immune-mediated diseases, we identified a rare regulatory variant rs200395694:G > T located in intron 4 of the MEF2D gene encoding the myocyte-specific enhancer factor 2D transcription factor and associated with SLE in Swedish cohorts (504 SLE patients and 839 healthy controls, p = 0.014, CI = 1.1-10). Fisher's exact test revealed an association between the genetic variant and a triad of disease manifestations including Raynaud, anti-U1-ribonucleoprotein (anti-RNP), and anti-Smith (anti-Sm) antibodies (p = 0.00037) among the patients. The DNA-binding activity of the allele was further studied by EMSA, reporter assays, and minigenes. The region has properties of an active cell-specific enhancer, differentially affected by the alleles of rs200395694:G > T. In addition, the risk allele exerts an inhibitory effect on the splicing of the alternative tissue-specific isoform, and thus may modify the target gene set regulated by this isoform. These findings emphasize the potential of dissecting traits of complex diseases and correlating them with rare risk alleles with strong biological effects.
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| 2. |
- Lundtoft, Christian, et al.
(författare)
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Complement C4 copy number variation is linked to SSA/Ro and SSB/La autoantibodies in systemic inflammatory autoimmune diseases.
- 2022
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Ingår i: Arthritis & rheumatology (Hoboken, N.J.). - : Wiley. - 2326-5205 .- 2326-5191. ; 74:8, s. 1440-1450
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Tidskriftsartikel (refereegranskat)abstract
- Copy number variation of the C4 complement components, C4A and C4B, has been associated with systemic inflammatory autoimmune diseases. We asked if C4 copy number variation is connected to the autoimmune repertoire in systemic lupus erythematosus (SLE), primary Sjögren's syndrome (pSS) or myositis.Using targeted DNA sequencing, we determined the copy number and genetic variants of C4 in 2,290 well-characterised Scandinavian patients with SLE, pSS or myositis, and 1,251 healthy controls.A prominent relationship was observed between C4A copy number and the presence of SSA/SSB autoantibodies, which was shared between the three diseases. The strongest association was detected for patients with autoantibodies against both SSA and SSB and 0 C4A copies when compared to healthy controls (OR=18.0; CI95% : 10.2-33.3), whereas a weaker association was seen for patients without SSA/SSB autoantibodies (OR=3.1; CI95% : 1.7-5.5). The copy number of C4 correlated positively with C4 plasma levels. Further, a common loss-of-function variant in C4A leading to reduced plasma C4 was more prevalent in SLE patients with a low copy number of C4A. Functionally, we showed that absence of C4A reduced the individuals' capacity to deposit C4b on immune complexes.We show that a low C4A copy number more strongly is associated with the autoantibody repertoire than with the clinically defined disease entities. These results may have implication for understanding the aetiopathogenetic mechanisms of systemic inflammatory autoimmune diseases, and for patient stratification when taking the genetic profile into account. This article is protected by copyright. All rights reserved.
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| 3. |
- Sandling, Johanna K., et al.
(författare)
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Molecular pathways in patients with systemic lupus erythematosus revealed by gene-centred DNA sequencing
- 2021
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 80:1, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Systemic lupus erythematosus (SLE) is an autoimmune disease with extensive heterogeneity in disease presentation between patients, which is likely due to an underlying molecular diversity. Here, we aimed at elucidating the genetic aetiology of SLE from the immunity pathway level to the single variant level, and stratify patients with SLE into distinguishable molecular subgroups, which could inform treatment choices in SLE. Methods: We undertook a pathway-centred approach, using sequencing of immunological pathway genes. Altogether 1832 candidate genes were analysed in 958 Swedish patients with SLE and 1026 healthy individuals. Aggregate and single variant association testing was performed, and we generated pathway polygenic risk scores (PRS). Results: We identified two main independent pathways involved in SLE susceptibility: T lymphocyte differentiation and innate immunity, characterised by HLA and interferon, respectively. Pathway PRS defined pathways in individual patients, who on average were positive for seven pathways. We found that SLE organ damage was more pronounced in patients positive for the T or B cell receptor signalling pathways. Further, pathway PRS-based clustering allowed stratification of patients into four groups with different risk score profiles. Studying sets of genes with priors for involvement in SLE, we observed an aggregate common variant contribution to SLE at genes previously reported for monogenic SLE as well as at interferonopathy genes. Conclusions: Our results show that pathway risk scores have the potential to stratify patients with SLE beyond clinical manifestations into molecular subsets, which may have implications for clinical follow-up and therapy selection.
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