Autoimmune mechanisms and genetic susceptibility contribute to the pathogenesis of primary Sjögren’s syndrome and SLE. These chronic systemic autoimmune diseases have many serological and clinical features in common and have an impact on daily life. The studies in this thesis aim to elucidate their autoimmune mechanisms, define susceptibility genes and evaluate effects of androgen supplement on health-related quality of life. Autoantibodies against α-fodrin, a widely distributed cytoskeletal protein, were detected at similar frequencies in sera from patients with primary and secondary Sjögren’s syndrome and SLE. Consequently, testing for antibodies against α-fodrin would not add diagnostic value compared to conventional serological analysis and does not discriminate between these diseases. The type I interferon (IFN) system was found to be activated in primary Sjögren’s syndrome. IFN-α containing cells were detected in minor salivary gland biopsies, while sera from patients with primary Sjögren’s syndrome induced IFN-α production in the presence of apoptotic and necrotic cell material. This ability of sera correlated with the presence of antibodies against RNA-binding proteins and IFN-α production was dependent on RNA in immune complexes. The natural interferon producing cells/plasmacytoid dendritic cells (NIPC/PDC) were the IFN-α producers and blocking of FcγRIIa inhibited the production. Single nucleotide polymorphisms (SNPs) in two genes in the type I IFN signalling pathway, those for tyrosine kinase 2 and interferon regulatory factor 5, were strongly associated with SLE in a Swedish, Finnish and Icelandic population. The minor allele frequencies were lower in SLE patients than in healthy controls. These SNPs may decrease the function of the type I IFN system, thereby conferring protection against SLE. Supplementation with dehydroepiandrosterone (DHEA) in glucocorticoid treated women with SLE led to mild improvements in health-related quality of life in respect of mental well-being and sexuality, whereas physical well-being was unaffected.

In Molecular Medicine a wide range of methods are applied to analyze the genome to find genetic predictors of human disease. Apart from predisposing disease, genetic variations may also serve as genetic markers in the search for factors underlying complex diseases. Additionally, they provide a means to distinguish between species, analyze evolutionary relationships and subdivide species into strains. The development and improvement of laboratory techniques and computational methods was a spin-off effect of the Human Genome Project. The same techniques for analyzing genomic sequence variations may be used independent of organism or source of DNA or RNA. In this thesis, methods for high-throughput analysis of sequence variations were developed, evaluated and applied. The performance of several genotyping assays were investigated prior to genotyping 4000 samples in a co-operative genetic epidemiological study. Sequence variations in the estrogen receptor alpha gene were found to be associated with an increased risk of breast and endometrial cancer in Swedish women. Whole genome amplification (WGA) enables large scale genetic analysis of sparse amounts of biobanked DNA samples. The performance of two WGA methods was evaluated using four-color minisequencing on tag-arrays. Our in-house developed assay and “array of arrays” format allow up to 80 samples to be analyzed in parallel on a single microscope slide. Multiple displacement amplification by the Φ29 DNA polymerase gave essentially identical genotyping results as genomic DNA. To facilitate accurate method comparisons, a cluster quality assessment approach was established and applied to assess the performance of four commercially available DNA polymerases in the tag-array minisequencing assay. A microarray method for genotyping human group A rotavirus (HRV) was developed and applied to an epidemiological survey of infectious HRV strains in Nicaragua. The method combines specific capture of amplified viral sequences on microarrays with genotype-specific DNA-polymerase mediated extension of capture oligonucleotides with fluorescent dNTPs.

In this thesis, the four-color fluorescence tag-microarray minisequencing system pioneered by our group was further developed and applied for analysing genetic variation in human DNA and RNA. A SNP marker panel representing different chromosomal regions was established and used for identification of informative SNP markers for monitoring chimerism after stem cell transplantation (SCT). The success of SCT was monitored by measuring the allelic ratios of informative SNPs in follow-up samples from nine patients with leukaemia. The results agreed with data obtained using microsatellite markers. Further the same SNP marker panel was used for evaluation of two whole genome amplification methods, primer extension preamplification (PEP) and multiple displacement amplification (MDA) in comparison with genomic DNA with respect to SNP genotyping success and accuracy in tag-array minisequencing. Identical results were obtained from MDA products and genomic DNA. The tag-microarray minisequencing system was also established for multiplexed quantification of imbalanced expression of SNP alleles. Two endothelial cell lines and a panel of ten coding SNPs in five genes were used as model system. Six heterozygous SNPs were genotyped in RNA (cDNA) from the cell lines. Comparison of the relative amounts of the SNPs alleles in cDNA to heterozygote SNPs in genomic DNA displayed four SNPs with significant imbalanced expression between the SNP alleles. Finally, the tag-array minisequencing system was modified for detection of splice variants in mRNA from five leukaemia cell lines. A panel of 20 cancer-related genes with 74 alternatively splice variants was screened. Over half of the splice variants were detected in the cell lines, and similar alternative splicing patterns were observed in each cell line. The results were verified by size analysis of the PCR product subjected to the minisequencing primer extension reaction. The data from both methods agreed well, evidencing for a high sensitivity of our system.

Immunity to asexual blood-stage of Plasmodium falciparum malaria is believed to be associated with protective antibodies of certain immunoglobulin classes and subclasses. This thesis addressed the importance of antibodies in relation to malaria infection and their effective interactions with Fc gamma receptor IIa (FcyRIIa) polymorphisms. Our data indicate that the frequency of FcyRIIa-R/R131 genotype was statistically significantly higher in Sudanese patients with severe malaria, while the FcyRIIa-H/H131 genotype showed a significant association with mild malaria. The levels of IgG1 and IgG3 subclass antibodies were statistically higher in the mild malaria patients. The Fulani ethnic group in West Africa has been shown to be relatively resistant to malaria. We investigated the possible impact of FcyRIIa polymorphisms in the Fulani and non-Fulani in Mali and Sudan, and analysed their malaria-reactive IgG subclass profiles. The FcyRIIa-H/H131 genotype and H131-allele were found to be prevalent in the Fulani while R131-allele was prevalent in non-Fulani. The Fulani had higher serum levels of IgG1-3, with higher proportion of IgG2 than the non-Fulani. Most clinico-epidemiology studies have been in areas with holo- and hyper-malaria endemicity. We have analysed antibody responses to a panel of six blood-stage antigens in relation to clinical malaria outcome in mesoendemic Sudan. Our results revealed a linear association with anti-AMA-1 IgG1 antibodies and reduced risk of severe malaria while a non-linear relationship with IgG3 antibodies was observed for MSP-2, MSP-3 and GLURP. In the combined final model, the highest levels of IgG1 subclass antibodies to AMA-1, GLURP-R0, and the highest levels of IgG3 subclass antibodies reactive to 3D7 MSP-2 were independently associated with a reduced risk of clinical malaria. Taken together, these data suggest a possible association between FcyRIIa-R/H131 and anti-malarial antibody responses in the clinical outcome of malaria.

In autoimmune diseases an individual’s immune system becomes targeted at the body’s own healthy cells. The aim of this thesis was to identify genetic risk factors for the two autoimmune diseases multiple sclerosis (MS) and systemic lupus erythematosus (SLE). In Study I, we found that genetic variation in the interferon regulatory factor 5 gene (IRF5), previously shown to be associated with SLE, rheumatoid arthritis and inflammatory bowel diseases, was associated also with MS. An insertion/deletion polymorphism in the first intron of IRF5 is as a good functional candidate for this association. IRF5, together with the signal transducer and activator of transcription 4 gene (STAT4), are the most important genetic risk factors for SLE, outside the HLA region. In Study II we showed using a family-based study design that genetic variation in STAT4 is associated with SLE also in the Finnish population. In Study III, we investigated a STAT4 risk allele for SLE for its association with cardiovascular disease in SLE patients. The risk allele of STAT4 proved to be strongly associated with ischemic cerebrovascular disease and anti-phospholipid antibodies in SLE patients. A possible mechanism for this association is that the risk allele leads to increased production of pro-thrombotic anti-phospholipid antibodies, which in turn increases the risk for stroke. Both IRF5 and STAT4 are involved in signalling of the type I interferon system. In Study IV, we investigated 78 additional genes in this system for their association with SLE in a Swedish cohort. The most promising results were followed up in additional patients and controls from Sweden and the US. Two novel SLE genes were identified. In Study V a large follow-up of a genome-wide association study was performed. Five new SLE loci were identified: TNIP1, PRDM1, JAZF1, UHRF1BP1 and IL10. A number of genes previously shown to be associated with other autoimmune diseases were also tested for association with SLE. This analysis identified the type I interferon system gene IFIH1 as a novel SLE risk locus. These studies confirms the central role of the type I interferon system in SLE and further suggests common genetic risk factors in autoimmunity.

Developments within the field of genetic analysis have during the last decade become enormous. Advances in DNA sequencing technology have increased throughput from a thousand bases to over a billion bases in a day and decreased the cost thousandfold per base. Nevertheless, to sequence complex genomes like the human is still very expensive and efforts to attain even higher throughputs for less money are undertaken by researchers and companies. Genotyping systems for single nucleotide polymorphism (SNP) analysis with whole genome coverage have also been developed, with low cost per SNP. There is, however, a need for genotyping assays that are more cost efficient per sample with considerably higher accuracy. This thesis is focusing on a technology, based on competitive allele-specific extension and microarray detection, for genetic analysis. To increase specificity in allele-specific extension (ASE), a nucleotide degrading enzyme, apyrase, was introduced to compete with the polymerase, only allowing the fast, perfect matched primer extension to occur. The aim was to develop a method for analysis of around twenty loci in hundreds of samples in a high-throughput microarray format. A genotyping method for human papillomavirus has been developed, based on a combination of multiplex competitive hybridization (MUCH) and apyrase-mediated allele-specific extension (AMASE). Human papillomavirus (HPV), which is the causative agent in cervical cancer, exists in over a hundred different types. These types need to be determined in clinical samples. The developed assay can detect the twenty-three most common high risk types, as well as semi-quantifying multiple infections, which was demonstrated by analysis of ninety-two HPV-positive clinical samples. More stringent conditions can be obtained by increased reaction temperature. To further improve the genotyping assay, a thermostable enzyme, protease, was introduced into the allele-specific extension reaction, denoted PrASE. Increased sensitivity was achieved with an automated magnetic system that facilitates washing. The PrASE genotyping of thirteen SNPs yielded higher conversion rates, as well as more robust genotype scoring, compared to ASE. Furthermore, a comparison with pyrosequencing, where 99.8 % of the 4,420 analyzed genotypes were in concordance, indicates high accuracy and robustness of the PrASE technology. Single cells have also been analyzed by the PrASE assay to investigate loss of alleles during skin differentiation. Single cell analysis is very demanding due to the limited amounts of DNA. The multiplex PCR and the PrASE assay were optimized for single cell analysis. Twenty-four SNPs were genotyped and an increased loss of genetic material was seen in cells from the more differentiated suprabasal layers compared to the basal layer. / QC 20100714

The human genome reference sequence has given us a two‐dimensional blueprint of our inherited code of life, but we need to employ modern‐day technology to expand our knowledge into a third dimension. Inter‐individual and intra‐individual variation has been shown to be larger than anticipated, and the mode of genetic regulation more complex. Therefore, the methods that were once used to explain our fundamental constitution are now used to decipher our differences. Over the past four years, throughput from DNA‐sequencing platforms has increased a thousand‐fold, bearing evidence of a rapid development in the field of methods used to study DNA and the genomes it constitutes. The work presented in this thesis has been carried out as an integrated part of this technological evolution, contributing to it, and applying the resulting solutions to answer difficult biological questions. Papers I and II describe a novel approach for microarray readout based on immobilization of magnetic particles, applicable to diagnostics. As benchmarked on canine mitochondrial DNA, and human genomic DNA from individuals with cystic fibrosis, it allows for visual interpretation of genotyping results without the use of machines or expensive equipment. Paper III outlines an automated and cost‐efficient method for enrichment and titration of clonally amplified DNA‐libraries on beads. The method uses fluorescent labeling and a flow‐cytometer to separate DNA‐beads from empty ones. At the same time the fraction of either bead type is recorded, and a titration curve can be generated. In paper IV we combined the highly discriminating multiplex genotyping of trinucleotide threading with the digital readout made possible by massively parallel sequencing. From this we were able to characterize the allelic distribution of 88 obesity related SNPs in a population of 462 individuals enrolled at a childhood obesity center. Paper V employs the throughput of present day DNA sequencingas it investigates deep into sun‐exposed skin to find clues on the effects of sunlight during the course of a summer holiday. The tumor suppressor p53 gene was targeted, only to find that despite its well‐documented involvement in the disease progression of cancers, an estimated 35,000 novel sun‐induced persistent p53 mutations are added and phenotypically tolerated in the skin of every individual every year. The last paper, VI, describes a novel approach for finding breast cancer biomarkers. In this translational study we used differential protein expression profiles and sequence capture to select and enrich for 52 candidate genes in DNA extracted from ten tumors. Two of the genes turned out to harbor protein‐altering mutations in multiple individuals.

Background. Familial Amyloidosis with Polyneuropathy (FAP) is an autosomal dominantly inherited systemic amyloid disease. The disease is caused by mutations in the transthyretin (TTR) gene, where close to 100 different amyloidogenic mutations have been identified. FAP is found worldwide, but endemic areas with a high frequency of patients are found in Portugal, Japan and northern Sweden. Cases from these endemic areas all share the same TTR c.148G>A, p.V50M ("V30M") mutation, but the phenotype of the disease varies between the areas, and also within the endemic areas. The mean onset of the disease is two decades earlier in Portugal and Japan compared to Sweden, but late as well as early age at onset cases occur within all the populations. Interestingly, the different populations all display a maternal anticipation, where an earlier onset is observed for those individuals who inherit the trait from their mother. Since substantial variation in the phenotype is observed for different populations, epigenetic/genetic and/or environmental factors must exert a significant impact on the penetrance of the disease. Amyloid formation is caused by conformational changes of proteins, which facilitates their assembly into fibrils, amyloid. Oxidative stress can mediate conformational changes of proteins and since the mitochondria regulate oxidative processes within the cell, mitochondrial function may affect amyloid formation. The mitochondrial DNA is a non-nuclear DNA, which is entirely maternally inherited, and therefore could be related to the observed maternal anticipation of the disease. In addition, differences within the surrounding regions of the TTR gene may have an impact on the transcription of the gene and thereby on the expression of the different alleles. Material and methods. DNA from early and late onset V30M cases and from non-carriers (the latter utilised as controls) from Swedish, French, Japanese and Portuguese populations were analysed. In addition, DNA from healthy Swedish V30M carriers was analysed. Conventional analytical methods were employed, such as PCR, sequencing and genotyping. Conventional statistical methods used were t-test, Chi-squared test and maximum likelihood. Results. The study of V30M carrier frequency in two counties (Lycksele and Skellefteå) within the Swedish endemic area revealed a carrier frequency of 2.14% and 2.54%, respectively. The mitochondrial haplogroup analysis showed that in populations with generally late onset (French and Swedish), the haplogroup distribution of late onset cases resembled that of the controls derived from the same area, whereas haplogroup distribution for early onset patients was significantly different. The most pronounced difference was for the rare haplogroup K, of which early onset cases had a higher frequency than the controls. Analysis of the Portuguese population, with predominantly early onset, showed that haplogroup distribution for early onset cases were similar to the Portuguese control group, which had a different distribution than the Swedish control group. By analysis of pedigrees from Swedish and Portuguese patients it could be shown that mitochondrial genetic variation entirely could explain maternal anticipation in the Portuguese patients, whereas for Swedish patients, an additional parent of origin effect is present. Our analysis of the TTR gene disclosed a polymorphism (rs62093482) in the 3'UTR region of the Swedish patients. This polymorphism was found in all V30M carriers, irrespective of symptoms. In addition, homozygous TTR V30M carriers were homozygous also for the polymorphism. Since Swedish patients share a common founder this polymorphism thus is localised on the V30M allele. This polymorphism was found in only 4% of the Swedish controls. French controls showed the same frequency, but none of the French V30M patients displayed the polymorphism. In the Japanese population the polymorphism was not present at all. Interestingly, this polymorphism generates a potential binding site for microRNA and thereby possibly could down-regulate the expression of the mutated TTR allele. Conclusions. The carrier frequency in the endemic area is remarkably high, above 2% in the Lycksele and Skellefteå areas. The prevailing haplogroup distributions in the different endemic areas are consistent between the general population and the patient group with the predominant phenotype of that area. Mitochondrial genetic differences may explain maternal anticipation in Portuguese patients, and have an influence in Swedish patients. A polymorphism in the 3'UTR regulatory region of the mutated TTR allele is found in all Swedish patients. This polymorphism may down-regulate TTR V30M expression and thereby contribute to the late onset of the disease noted in the Swedish population.

Understanding the genetic basis of biological processes is a fundamental component of modern ecology and evolutionary biology studies. With the recent advent of next generation sequencing (NGS) technologies, it is now possible to perform large genome and transcriptome projects for ecologically important non-model species. In this thesis, I focused on the development and application of genomic resources of two non-model bird species, the black grouse (Tetrao tetrix) and the great snipe (Gallinago media). Using the chicken genome as a reference, I developed a reference guided NGS pipeline to assemble the complete draft genome of black grouse. The draft genome has a good coverage of the main 29 chromosomes of the chicken genome. The genome was used to develop a vast number of genetic markers. Comparing this genome with that of other species, I identified the genomic regions which were important for the lineage specific evolution of black grouse. I also sequenced and characterised the spleen transcriptome of the black grouse. I identified and validated a large number of gene-based microsatellite markers from the transcriptome and identified and confirmed the expression of immune related genes. Using a similar RNA-Seq approach, I also sequenced the blood transcriptomes of 14 great snipe males with different mating success. I identified genes and single nucleotide polymorphisms (SNPs) which might be related to male mating success in this species, both in terms of gene expression levels and genetic variation structure. For the immunologically important major histocompatibility complex (MHC) gene region of black grouse, I constructed a fosmid library and used it to sequence the complete core MHC region of this species. This resource allowed me to perform a comprehensive comparative genomics analysis of the galliform MHC, by which I found that some genes in this region were affected by selective forces. I was also able to develop a single locus genotyping protocol for the duplicated MHC BLB (class IIB) genes and found that the two black grouse BLB loci followed different evolutionary trajectories. This thesis set an example of developing genomic resources in non-model species and applying them in addressing questions relevant to ecology and evolutionary biology.

Introducción: analizamos la relación entre fracturas y densidad mineral ósea (DMO) y los SNP (polimorfismos de un solo nucleótido) rs3102735 (163 A/G), rs3134070 (245 T/G) y rs2073618 (1181 G/C) de OPG, el SNP rs2277438 SNP de RANKL, el SNP rs7121 (393 T/C) de GNAS1 y del SNP rs219780 del gen CLDN14 en pacientes con HPP (hiperparatiroidismo primario) esporádico. Métodos: reclutamos 298 pacientes con HPP y 328 voluntarios sanos en un estudio transversal. Analizamos historia de fracturas o litiasis renal, parámetros bioquímicos, DMO en columna lumbar, cadera total, cuello femoral y radio distal y genotipado de los SNP mencionados. Resultados: no encontramos diferencias entre los genotipos de ninguno de los SNP estudiados en relación con la frecuencia de fracturas en HPP o en sujetos control. La DMO fue menor en el radio en los HPP homocigotos para el alelo menor en comparación con el resto de grupos en los SNP de OPG (163 A/G) y (245 T/G) pero no en sujetos control. En el resto de los SNP estudiados no encontramos diferencias entre genotipos y DMO en los sujetos con HPP o control excepto en el SNP de OPG (1181 G/C) en sujetos control con mayor DMO lumbar en el grupo CC respecto del GG. Conclusiones: los sujetos con HPP y homocigotos para el alelo menor (GG) en los SNP rs3102735 (163 A/G) y rs3134070 (245 T/G) de OPG tienen menor DMO en el radio distal. El resto de SNP estudiados no parecen influir en la diferente expresión de las manifestaciones óseas del HPP. / Background: we analyze the relationship between fractures and BMD (bone mineral density) and the rs3102735 (163 A/G), rs3134070 (245 T/G) and rs2073618 (1181 G/C) SNPs of the OPG, the rs2277438 SNP of the RANKL, the rs7121 SNP (393 T/C) of GNAS1 and the rs219780 of CLDN14 in patients with sporadic PHPT (primary hyperparathyroidism). Methods: We enrolled 298 Caucasian patients with PHPT and 328 healthy volunteers in a cross-sectional study. We analyzed history of fractures or renal lithiasis, biochemical determinants, BMD measurements in the lumbar spine, total hip, femoral neck and distal radius, and genotyping for the SNPs to be studied. Results: Regarding the frequency of fractures we found no differences between genotypes in any of the SNPs studied in the PHPT or in the control subjects groups. Significant lower BMD in the distal radius was found in the minor allele homozygotes (GG) compared to heterozygotes and major allele homozygotes in both OPG rs3102735 (163 A/G) and OPG rs3134070 (245 T/G) SNPs in those with PHPT but not in control subjects. We found no difference between genotypes of the rest of the SNPs studied in PHPT or control subjects with the exception of SNP OPG rs2073618 (1181 G/C) in control CC subjects which showed higher lumbar BMD than GG ones. Conclusions: Subjects with PHPT and minor homocygote genotype (GG) for the OPG rs3102735 (163 A/G) and OPG rs3134070 (245 T/G) SNPs have lower BMD in the distal radius. All the other SNPs studied do not appear to influence the different expression of HPP in bone.