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- Reid, Sarah, et al.
(författare)
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High Genetic Risk Score Is Associated with Increased Organ Damage in SLE
- 2017
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Ingår i: Arthritis & Rheumatology. - : John Wiley & Sons. - 2326-5191 .- 2326-5205. ; 69
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background/Purpose: Systemic lupus erythematosus (SLE) is a chronic, autoimmune disease with a complex genetic etiology. Over 80 risk genes for SLE have been identified and some genetic variants have demonstrated association with specific disease manifestations, such as STAT4 and nephritis. The overall effect of a patient’s hereditary risk factors on disease severity has so far not been studied. We therefore assessed the relationship between high genetic risk and development of organ damage in SLE.Methods: Patients with SLE, who met at least 4 ACR criteria (n = 1012), were genotyped using a 200K Immunochip SNP Array (Illumina). A genetic risk score (GRS) was assigned to each patient based on the single nucleotide polymorphisms (SNPs) which in previous studies have shown association (p<5×10-8) with SLE according to Morris, et al (Nat Genet, 2016. 48(8): p. 940-6). For 32 loci the SLE GWAS SNP was available on the ImmunoChip. For each SNP, the natural logarithm of the odds ratio (OR) for SLE susceptibility was multiplied by the number of risk alleles in each individual. The sum of all products for each patient was defined as the GRS. Information regarding organ damage according to Systemic Lupus International Collaborating Clinics / American College of Rheumatology Damage Index (SLICC-DI), disease manifestations, antibody profile, medication, current disease activity, age at diagnosis and sex was retrieved from medical records. Statistical analyzes were performed using Statistica 13.2 (Statsoft).Results: In an ordinal regression model, with SLICC-DI (0, 1, 2, 3, 4 and >4 points) as outcome and age and GRS as independent variables, an association was found between GRS and SLICC-DI (OR1.16 (1.03-1.31), p=0.015). The relationship was more pronounced for patients under 60 years of age (OR1.30 (1.11-1.52) p=7.1×10-4). Using a linear regression model, a negative relationship was observed between GRS and age at diagnosis (β = -0.13, p=1.5×10-5).When analyzing the 11 SLE criteria (ACR-82) using a logistic regression model associations were observed between GRS and nephritis (OR 1.26 (1.09-1.45), p=0.0015), the immunological criteria (OR 1.31 (1.13-1.51), p = 3.2×10-4) and arthritis (OR 0.84 (0.71-1.00), p=0.044). A high GRS was also associated with presence of anti-dsDNA (OR 1.37 (1.15-1.62), p=9.4×10-7) and low complement levels (OR 1.32 (1.03-1.68), p=0.044). No association was observed between GRS and disease activity at the time of follow-up and there was no difference in GRS between men and women with SLE.Conclusion: In patients with SLE, there is an association between a high genetic risk score and early disease onset. In addition, patients with high genetic risk scores have a higher risk of developing permanent organ damage compared to individuals with fewer risk genes. Our findings indicate that genetic profiling of patients with SLE may provide a tool for predicting severity of the disease.
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| 4. |
- Rönn, Ann-Charlotte, 1969-
(författare)
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Analysis of Nucleotide Variations in Non-human Primates
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many of our closest relatives, the primates, are endangered and could be extinct in a near future. To increase the knowledge of non-human primate genomes, and at the same time acquire information on our own genomic evolution, studies using high-throughput technologies are applied, which raises the demand for large amounts of high quality DNA.In study I and II, we evaluated the multiple displacement amplification (MDA) technique, a whole genome amplification method, on a wide range of DNA sources, such as blood, hair and semen, by comparing MDA products to genomic DNA as templates for several commonly used genotyping methods. In general, the genotyping success rate from the MDA products was in concordance with the genomic DNA. The quality of sequences of the mitochondrial control region obtained from MDA products from blood and non-invasively collected semen samples was maintained. However, the readable sequence length was shorter for MDA products.Few studies have focused on the genetic variation in the nuclear genes of non-human primates. In study III, we discovered 23 new single nucleotide polymorphisms (SNPs) in the Y-chromosome of the chimpanzee. We designed a tag-microarray minisequencing assay for genotyping the SNPs together with 19 SNPs from the literature and 45 SNPs in the mitochondrial DNA. Using the microarray, we were able to analyze the population structure of wild-living chimpanzees.In study IV, we established 111 diagnostic nucleotide positions for primate genera determination. We used sequence alignments of the nuclear epsilon globin gene and apolipoprotein B gene to identify positions for determination on the infraorder and Catarrhini subfamily level, respectively, and sequence alignments of the mitochondrial 12S rRNA (MT-RNR1) to identify positions to distinguish between genera. We designed a microarray assay for immobilized minisequencing primers for genotyping these positions to aid in the forensic determination of an unknown sample.
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| 5. |
- Ahlford, Annika, 1980-
(författare)
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Applications of Four-Colour Fluorescent Primer Extension Technology for SNP Analysis and Discovery
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Studies on genetic variation can reveal effects on traits and disease, both in humans and in model organisms. Good technology for the analysis of DNA sequence variations is critical. Currently the development towards assays for large-scale and parallel DNA sequencing and genotyping is progressing rapidly. Single base primer extension (SBE) is a robust reaction principle based on four-colour fluorescent terminating nucleotides to interrogate all four DNA nucleotides in a single reaction. In this thesis, SBE methods were applied to the analysis and discovery of single nucleotide polymorphism (SNP) in the model organism Drosophila melanogaster and in humans. The tag-array minisequencing system in a microarray format is convenient for intermediate sized genotyping projects. The system is scalable and flexible to adapt to specialized and novel applications. In Study I of the thesis a tool was established to automate quality control of clustered genotype data. By calculating “Silhouette scores”, the SNP genotype assignment can be evaluated by a single numeric measure. Silhouette scores were then applied in Study I to compare the performance of four DNA polymerases and in Study III to evaluate freeze-dried reagents in the tag-array minisequencing system. The characteristics of the tag-array minisequencing system makes it suitable for inexpensive genome-wide gene mapping in the fruit fly. In Study II a high-resolution SNP map, and 293 genotyping assays, were established across the X, 2nd and 3rd chromosomes to distinguish commonly used Drosophila strains. A database of the SNP markers and a program for automatic allele calling and identification of map positions of mutants was also developed. The utility of the system was demonstrated by rapid mapping of 14 genes that disrupt embryonic muscle patterning. In Study III the tag-array minisequencing system was adapted to a lab-on-a-chip format for diagnostic testing for mutations in the TP53 gene. Freeze-drying was evaluated for storing reagents, including thermo-sensitive enzymes, on the microchip to reduce the complexity of the integrated test. Correct genotyping results were obtained using freeze-dried reagents in each reaction step of the genotyping protocol, both in test tubes and in single polymer test chambers. The results showed the potential of the approach to be implemented in fully integrated systems. The four-colour chemistry of SBE has been developed further to allow massively parallel sequencing (MPS) of short DNA fragments as in the Genome Analyzer system (Solexa/Illumina). In Study IV MPS was used to compare Nimblegen arrays and the SureSelect solution-based system for targeted enrichment of 56 continuous human candidate-gene regions totalling 3.1 Mb in size. Both methods detected known SNPs and discovered novel SNPs in the target regions, demonstrating the feasibility for complexity reduction of sequencing libraries by hybridization methods.
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| 7. |
- Blom, Titta S, et al.
(författare)
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Defective endocytic trafficking of NPC1 and NPC2 underlying infantile Niemann-Pick type C disease
- 2003
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 12:3, s. 257-272
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Niemann–Pick type C (NPC) disease is a fatal recessively inherited lysosomal cholesterol-sphingolipidosis. Mutations in the NPC1 gene cause ∼95% of the cases, the rest being caused by NPC2 mutations. Here the molecular basis of a severe infantile form of the disease was dissected. The level of NPC1 protein in the patient fibroblasts was similar to that in control cells. However, the protein was partially mislocalized from late endocytic organelles diffusely to the cell periphery. In contrast, NPC2 was upregulated and accumulated in cholesterol storing late endocytic organelles. Two point mutations and a four-nucleotide deletion were identified in the NPC1 gene, leading to the amino acid substitutions C113R, P237S and deletion of 37 C-terminal amino acids (delC). Overexpression of individual NPC1 mutations revealed that delC produced an unstable protein, wild-type and NPC1-P237S colocalized with Rab7-positive late endosomes whereas NPC1-C113R localized to the ER, Rab7-negative endosomes and the cell surface. Expression of wild-type or NPC1-P237S cleared the lysosomal cholesterol accumulation in NPC1-deficient cells whereas C113R or delC did not. In the Finnish and Swedish population samples, alleles carrying C113R or delC were not identified, whereas ∼5% of the alleles carried P237S. Our studies identify P237S as a prevalent NPC1 polymorphism and delC and C113R as deleterious NPC1 mutations. Moreover, they show that delC leads to rapid degradation of NPC1 and C113R to endocytic missorting of the protein. These changes are accompanied by lysosomal accumulation of NPC2, suggesting that NPC1 governs the endocytic transport of NPC2.
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| 8. |
- Bolin, Karin, 1982-, et al.
(författare)
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Variants in BANK1 are associated with lupus nephritis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: Lupus nephritis (LN) is a cause of significant morbidity in SLE. While the genetic background to SLE has been well characterized, less is known about genes predisposing to LN.Methods: The study consisted of 2886 SLE patients, including 947 (33%) with LN. The discovery cohort (Sweden, n=1091) and replication cohort 1 (US, n=962) were genotyped on the Immunochip and replication cohort 2 (Norway/Denmark, n=833) on a custom array chip. Allele frequencies were compared between patients with LN, proliferative nephritis, end-stage renal disease and LN negative patients. SNPs with p-value <0.001 in the discovery cohort were analyzed in replication cohort 1. Ten SNPs associated with LN in the discovery cohort (p<0.0002) were genotyped in replication cohort 2. DNA methylation data were available for 180 LN patients from the discovery cohort.Results: In the discovery cohort, six gene loci were associated with LN (p<1x10-4, NFKBIA, CACNA1S, ITGA1, BANK1, OR2Y and PHCA). SNPs in BANK1 showed the strongest association with LN in replication cohort 1 (p=9.5x10-4), with a tendency for an association in replication cohort 2 (p=0.052). In a meta-analysis of all three cohorts the association between LN and BANK1 rs4699259, was strengthened (p=1.7x10‑7). There were no associations to proliferative nephritis or ESRD in the meta-analysis. Methylation quantitative trait loci (MeQTL) effects between a CpG site and several SNPs in BANK1 were identified.Conclusion: Genetic variations in BANK1 are associated with LN. There is evidence for genetic regulation of DNA methylation within the BANK1 locus, however, the exact role of BANK1 in LN pathogenesis remains to be elucidated.
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