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- Andréasson, Hanna, 1975-
(author)
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Sensitive Forensic DNA Analysis : Application of Pyrosequencing and Real-time PCR Quantification
- 2005
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Doctoral thesis (other academic/artistic)abstract
- The field of forensic genetics is growing fast and the development and optimisation of more sensitive, faster and more discriminating forensic DNA analysis methods is highly important. In this thesis, an evaluation of the use of novel DNA technologies and the development of specific applications for use in forensic casework investigations are presented.In order to maximise the use of valuable limited DNA samples, a fast and user-friendly Real-time PCR quantification assay, of nuclear and mitochondrial DNA copies, was developed. The system is based on the 5’ exonuclease detection assay and was evaluated and successfully used for quantification of a number of different evidence material types commonly found on crime scenes. Furthermore, a system is described that allows both nuclear DNA quantification and sex determination in limited samples, based on intercalation of the SYBR Green dye to double stranded DNA. To enable highly sensitive DNA analysis, Pyrosequencing of short stretches of mitochondrial DNA was developed. The system covers both control region and coding region variation, thus providing increased discrimination power for mitochondrial DNA analysis. Finally, due to the lack of optimal assays for quantification of mitochondrial DNA mixture, an alternative use of the Pyrosequencing system was developed. This assay allows precise ratio quantification of mitochondrial DNA in samples showing contribution from more than one individual.In conclusion, the development of optimised forensic DNA analysis methods in this thesis provides several novel quantification assays and increased knowledge of typical DNA amounts in various forensic samples. The new, fast and sensitive mitochondrial DNA Pyrosequencing assay was developed and has the potential for increased discrimination power.
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2. |
- Aulchenko, Yurii S, et al.
(author)
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Loci influencing lipid levels and coronary heart disease risk in 16 European population cohorts
- 2009
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 41:1, s. 47-55
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Journal article (peer-reviewed)abstract
- Recent genome-wide association (GWA) studies of lipids have been conducted in samples ascertained for other phenotypes, particularly diabetes. Here we report the first GWA analysis of loci affecting total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides sampled randomly from 16 population-based cohorts and genotyped using mainly the Illumina HumanHap300-Duo platform. Our study included a total of 17,797-22,562 persons, aged 18-104 years and from geographic regions spanning from the Nordic countries to Southern Europe. We established 22 loci associated with serum lipid levels at a genome-wide significance level (P < 5 x 10(-8)), including 16 loci that were identified by previous GWA studies. The six newly identified loci in our cohort samples are ABCG5 (TC, P = 1.5 x 10(-11); LDL, P = 2.6 x 10(-10)), TMEM57 (TC, P = 5.4 x 10(-10)), CTCF-PRMT8 region (HDL, P = 8.3 x 10(-16)), DNAH11 (LDL, P = 6.1 x 10(-9)), FADS3-FADS2 (TC, P = 1.5 x 10(-10); LDL, P = 4.4 x 10(-13)) and MADD-FOLH1 region (HDL, P = 6 x 10(-11)). For three loci, effect sizes differed significantly by sex. Genetic risk scores based on lipid loci explain up to 4.8% of variation in lipids and were also associated with increased intima media thickness (P = 0.001) and coronary heart disease incidence (P = 0.04). The genetic risk score improves the screening of high-risk groups of dyslipidemia over classical risk factors.
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4. |
- Beskow, Anna H., et al.
(author)
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Interaction of host and viral risk factors for development of cervical carcinoma in situ
- 2005
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 117:4, s. 690-692
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Journal article (other academic/artistic)abstract
- Infection by oncogenic human papillomavirus (HPV) is a necessary but not sufficient cause of cervical carcinoma. Several host genetic and viral factors have been reported to increase the risk of carcinoma development given an HPV infection. In our study, we have analysed the contribution of HPV 16 E6 sequence subtype and allelic variation at human leukocyte antigen (HLA) class II loci to the risk of developing cervical carcinoma in situ. Non-European-like HPV 16 E6 sequence subtypes were not found to be associated with an increased risk of cervical carcinoma, as compared to European-like variants. However, an association was found between the HPV 16 E6 L83V variant and the DR*04-DQ*03 haplotype. This association has been observed in several independent studies and shows that both the host HLA class II genotype and viral subtype will affect the risk of an infection progressing into cervical carcinoma.
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6. |
- Chatterjee, Koushik, et al.
(author)
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Fas and FasL gene polymorphisms are not associated with cervical cancer but differ among Black and Mixed-ancestry South Africans
- 2009
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In: BMC research notes. - : Springer Science and Business Media LLC. - 1756-0500. ; 2, s. 238-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Cervical cancer is one of the most important cancers in African women. Polymorphisms in the Fas (FasR) and Fas ligand (FasL) genes have been reported to be associated with cervical cancer in certain populations. This study investigated whether these polymorphisms are associated with cervical cancer or human papillomavirus (HPV) infection in South African women. FINDINGS: Participants were 447 women with invasive cervical cancer (106 black African and 341 women of mixed-ancestry) and 424 healthy women controls, matched by age, (101 black African and 323 women of mixed-ancestry) and domicile (rural or urban). Two polymorphisms in Fas gene (FasR-1377G/A, FasR-670A/G) and one in FasL gene (FasL844T/C) were genotyped by TaqMan. None of the polymorphisms, or the Fas haplotypes, showed a significant association with cervical cancer. There was also no association with HPV infection in the control group. However, on analysis of the control group, highly significant allele, genotype and haplotype differences were found between the two ethnic groups. There were generally low frequencies of FasR-1377A alleles, FasR-670A alleles and FasL-844C alleles in black women compared to the women of mixed-ancestry. CONCLUSION: This is the first study on the role of Fas and FasL polymorphisms in cervical cancer in African populations. Our results suggest that these SNPs are not associated with cervical cancer in these populations. The allele frequencies of the three SNPs differed markedly between the indigenous African black and mixed-ancestry populations.
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7. |
- Einarsdottir, Elisabet, 1974-
(author)
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Mapping genetic diseases in northern Sweden
- 2005
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Doctoral thesis (other academic/artistic)abstract
- The population of northern Sweden has previously been shown to be well suited for the mapping of monogenic diseases. In this thesis we have tested the hypothesis that this population could also be used for efficient identification of risk genes for common diseases. In Paper I we have hypothesised that despite the admixture of Swedish, Finnish and Sami, the northern Swedish population consists of sub-populations geographically restricted by the main river valleys running through the region. This geographic isolation, in combination with founder effects and genetic drift, could represent a unique resource for genetic studies. On the other hand, it also underlines the importance of accounting for this e.g. in genetic association studies. To test this hypothesis, we studied the patterns of marriage within and between river valley regions and compared allelic frequencies of genetic markers between these regions. The tendency to find a spouse and live in the river valley where one was born is strong, and allelic frequencies of genetic markers vary significantly between adjacent regions. These data support our hypothesis that the river valleys are home to distinct sub-populations and that this is likely to affect mapping of genetic diseases in these populations. In Paper II, we tested the applicability of the population in mapping HSAN V, a monogenic disease. This disease was identified in only three consanguineous individuals suffering from a severe loss of deep pain perception and an impaired perception of heat. A genome-wide scan combined with sequencing of candidate genes resulted in the identification of a causative point mutation in the nerve growth factor beta (NGFB) gene. In Paper III, a large family with multiple members affected by familial forms of type 1 diabetes mellitus (T1DM) and autoimmune thyroiditis (AITD) was studied. This syndrome was mapped to the IDDM12 region on 2q33, giving positive lodscores when conditioning on HLA haplotype. The linkage to HLA and to the IDDM12 region thus confirmed previous reports of linkage and/or association of T1DM and AITD to these loci and provided evidence that the same genetic factors may be mediating these diseases. This also supported the feasibility of mapping complex diseases in northern Sweden by the use of familial forms of these diseases. In Paper IV, we applied the same approach to study type 2 diabetes mellitus (T2DM). A non-parametric genome-wide scan was carried out on a family material from northern Sweden, and linkage was found to the calpain-10 locus, a previously described T2DM-susceptibility gene on 2q37. Together, these findings demonstrate that selecting for familial forms of even complex diseases, and choosing families from the same geographical region can efficiently reduce the genetic heterogeneity of the disease and facilitate the identification of risk genes for the disease.
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8. |
- Engelmark, Malin, 1977-
(author)
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Identifying Risk Genes for Cervical Cancer : Using Affected Sib-Pairs and Case-Control Materials from Sweden
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Cervical cancer is a multifactorial disease. Infection by oncogenic types of the human papillomavirus (HPV) is the major environmental risk factor and host genetic susceptibility also influences disease development. The aim of this thesis is to identify and analyse risk genes involved in the genetic predisposition to cervical carcinoma. A unique and extensive population-based affected sib-pair (ASP) material and a large case-control sample were used in the investigations.In paper I the human leukocyte antigen (HLA) class II DQB1 and DRB1 loci are confirmed, for the first time in a family-based material, as genetic susceptibility factors for cervical cancer. It is also proposed that the HLA class II DPB1 locus independently contributes to risk of developing disease. In addition, no evidence is found for an involvement of the class I HLA-B and HLA-A loci in the genetic predisposition. Paper II conclude that the Fas receptor –670 single nucleotide polymorphism (SNP) do not have a major impact on the susceptibility to cervical carcinoma in situ in the Swedish population. In paper III we show that interactions between the HPV16 E6 gene subtype and host HLA class II genotype potentially occur during infection and disease progression. Paper IV suggests that three chromosomal regions, 9q32, 12q24 and 16q24, contain risk factors of low to moderate effects on cervical cancer development. In paper V linkage signals are further identified between a 9q32 gene encoding the thymic stromal co-transporter (TSCOT) and the disease in ASPs with mean age over 30.5 years at diagnosis within the sib-pair.These findings are important contributions towards understanding more about the aetiology of this complex cancer. The identification of new susceptibility regions opens up for further characterisation, replication and candidate gene analysis.
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9. |
- Engelmark, Malin, et al.
(author)
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Polymorphisms in 9q32 and TSCOT are linked to cervical cancer in affected sib-pairs with high mean age at diagnosis
- 2008
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In: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 123:5, s. 437-443
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Journal article (peer-reviewed)abstract
- Cervical cancer is a multifactorial disease influenced by both environmental and genetic factors. We have previously found linkage to 9q32 in a genomewide scan of affected sib-pairs (ASPs) with cervical cancer and to the thymic stromal co-transporter (TSCOT), a candidate gene in this region. Here we examined the contribution of 9q32 and TSCOT to cervical cancer susceptibility using at larger material of 641 ASPs, 278 of which were included in the earlier genome-scan. Since heritable forms of cancer frequently show stronger genetic effects in families with early onset of disease, we stratified the ASPs into two groups based on mean age at diagnosis (MAAD) within sib-pairs. Surprisingly, ASPs with high MAAD (30.5-47.5 years) showed increased sharing at all microsatellite markers at 9q31.1-33.1 and linkage signals of up to MLS = 2.74 for TSCOT SNPs, while ASPs with low MAAD (19-30 years) showed no deviation from random genetic sharing (MLS = 0.00). The difference in allelic sharing between the two MAAD strata was significant (P < 0.005) and is not likely to be explained by the HLA haplotype, a previously known genetic susceptibility factor for cervical cancer. Our results indicate locus heterogeneity in the susceptibility to cervical cancer between the two strata, with polymorphisms in the 9q32 region mainly showing an effect in women with high MAAD.
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10. |
- Engelmark, Malin T., et al.
(author)
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Identification of susceptibility loci for cervical carcinoma by genome scan of affected sib-pairs
- 2006
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 15:22, s. 3351-3360
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Journal article (peer-reviewed)abstract
- Cervical cancer is caused by a combination of environmental and genetic risk factors. Infection by oncogenic types of human papillomavirus is recognized as the major environmental risk factor and epidemiological studies indicate that host genetic factors predispose to disease development. A number of genetic susceptibility factors have been proposed, but with exception of the human leukocyte antigen CHLA, class II, have not shown consistent results among studies. We have performed the first genomewide linkage scan using 278 affected sib-pairs to identify loci involved in susceptibility to cervical cancer. A two-step qualitative non-parametric linkage analysis using 387 microsatellites with an average spacing of 10.5 cM revealed excess allelic sharing at nine regions on eight chromosomes. These regions were further analysed with 125 markers to increase the map density to 1.28 cM. Nominal significant linkage was found for three of the nine loci [9q32 (maximum lod-score, MLS) =1.95, P < 0.002), 12q24 (MLS=1.25, P < 0.015) and 16q24 (MLS=1.35, P < 0.012)]. These three regions have previously been connected to human cancers that share characteristics with cervical carcinoma, such as esophageal cancer and Hodgkin's lymphoma. A number of candidate genes involved in defence against viral infections, immune response and tumour suppression are found in these regions. One such gene is the thymic stromal co-transporter (TSCOT). Analyses of TSCOT single nucleotide polymorphisms further strengthen the linkage to this region (MLS=2.40, P < 0.001). We propose that the 9q32 region contains susceptibility locus for cervical cancer and that TSCOT is a candidate gene potentially involved in the genetic predisposition to this disease.
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