Publications by authors named "Unnur Thorsteinsdottir"

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  • Dilated cardiomyopathy (DCM) is a major cause of heart failure, and this study analyzes genetic factors by examining 14,256 DCM cases and 36,203 participants from the UK Biobank for related traits.
  • Researchers discovered 80 genomic risk loci and pinpointed 62 potential effector genes tied to DCM, including some linked to rare variants.
  • The study uses advanced transcriptomics to explore how cellular functions contribute to DCM, showing that polygenic scores can help predict the disease in the general population and emphasize the importance of genetic testing and development of precise treatments.
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Mendelian Randomization studies indicate that BMI contributes to various diseases, but it's unclear if this is entirely mediated by BMI itself. This study examines whether disease risk from BMI-associated sequence variants is mediated through BMI or other mechanisms, using data from Iceland and the UK Biobank. The associations of BMI genetic risk score with diseases like fatty liver disease, knee replacement, and glucose intolerance were fully attenuated when conditioned on BMI, and largely for type 2 diabetes, heart failure, myocardial infarction, atrial fibrillation, and hip replacement.

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  • Immunoglobulin G (IgG) is the primary type of antibody in human blood and exists in four subclasses (IgG1 to IgG4), which are influenced by specific genes.
  • A genome-wide association study involving 4,334 adults and 4,571 children identified ten new variants and confirmed four known variants linked to IgG subclass levels, affecting conditions like asthma and autoimmune diseases.
  • Significant links were found between certain genetic allotypes and specific IgG subclasses, with notable findings showing that lower IgG4 levels can both protect against childhood asthma and increase the risk of inflammatory bowel disease.
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  • Multiple myeloma (MM) is a type of cancer affecting plasma cells, with a significant genetic component that is not fully understood.
  • A large genome-wide study identified 35 risk loci related to MM, including 12 new ones, and revealed two main inherited risk factors: longer telomeres and higher levels of B-cell maturation antigen (BCMA) and interleukin-5 receptor alpha (IL5RA) in the blood.
  • The genetic variant rs34562254-A increases the risk of MM by enhancing B-cell responses, contrasting with loss-of-function variants in TNFRSF13B that lead to B-cell immunodeficiency.
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Gene promoter and enhancer sequences are bound by transcription factors and are depleted of methylated CpG sites (cytosines preceding guanines in DNA). The absence of methylated CpGs in these sequences typically correlates with increased gene expression, indicating a regulatory role for methylation. We used nanopore sequencing to determine haplotype-specific methylation rates of 15.

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  • Early pregnancy bleeding and postpartum hemorrhage (PPH) present significant risks to maternal health, with PPH being the leading cause of maternal death and early bleeding often linked to pregnancy loss.
  • A meta-analysis identified five genetic loci associated with PPH, highlighting candidate genes (HAND2, TBX3, RAP2C/FRMD7) that interact with progesterone receptors, suggesting a connection between PPH and progesterone signaling issues.
  • While bleeding in early pregnancy didn't show specific genetic signals, it was strongly correlated with other human traits, indicating it may be influenced by multiple genetic and possibly socio-economic factors not yet fully understood.
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  • Type 2 diabetes (T2D) is a complex disease influenced by various genetic factors and molecular mechanisms that vary by cell type and ancestry.
  • In a large study involving over 2.5 million individuals, researchers identified 1,289 significant genetic associations linked to T2D, including 145 new loci not previously reported.
  • The study categorized T2D signals into eight distinct clusters based on their connections to cardiometabolic traits and showed that these genetic profiles are linked to vascular complications, emphasizing the role of obesity-related processes across different ancestry groups.
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Adenine phosphoribosyltransferase (APRT) deficiency is a rare , hereditary disorder characterized by renal excretion of 2,8-dihydroxyadenine (DHA), leading to kidney stone formation and chronic kidney disease (CKD). Treatment with a xanthine oxidoreductase inhibitor, allopurinol or febuxostat, reduces urinary DHA excretion and slows the progression of CKD. The method currently used for therapeutic monitoring of APRT deficiency lacks specificity and thus, a more reliable measurement technique is needed.

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X-chromosomal genetic variants are understudied but can yield valuable insights into sexually dimorphic human traits and diseases. We performed a sex-stratified cross-ancestry X-chromosome-wide association meta-analysis of seven kidney-related traits (n = 908,697), identifying 23 loci genome-wide significantly associated with two of the traits: 7 for uric acid and 16 for estimated glomerular filtration rate (eGFR), including four novel eGFR loci containing the functionally plausible prioritized genes ACSL4, CLDN2, TSPAN6 and the female-specific DRP2. Further, we identified five novel sex-interactions, comprising male-specific effects at FAM9B and AR/EDA2R, and three sex-differential findings with larger genetic effect sizes in males at DCAF12L1 and MST4 and larger effect sizes in females at HPRT1.

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Background: In 2021, the American College of Medical Genetics and Genomics (ACMG) recommended reporting actionable genotypes in 73 genes associated with diseases for which preventive or therapeutic measures are available. Evaluations of the association of actionable genotypes in these genes with life span are currently lacking.

Methods: We assessed the prevalence of coding and splice variants in genes on the ACMG Secondary Findings, version 3.

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Clonal hematopoiesis (CH) arises when a substantial proportion of mature blood cells is derived from a single hematopoietic stem cell lineage. Using whole-genome sequencing of 45,510 Icelandic and 130,709 UK Biobank participants combined with a mutational barcode method, we identified 16,306 people with CH. Prevalence approaches 50% in elderly participants.

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  • Migraine is a complicated neurovascular condition with varying symptoms, traditionally studied as a single type in genome-wide association studies (GWAS), but this research focuses on two main subtypes: migraine with aura (MA) and migraine without aura (MO).
  • The study analyzed large datasets from six European populations, identifying four new gene variants associated with MA and classifying 13 variants for MO, highlighting a significant frameshift variant in PRRT2 linked to MA and epilepsy.
  • Additionally, testing on rare variants showed that loss-of-function mutations in SCN11A provide strong protection against migraine, while another variant affecting KCNK5 offers large protection against both migraine and brain aneurysms, suggesting new avenues for treatment.
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  • Abdominal aortic aneurysm (AAA) has a significant genetic component, with a study identifying 141 genetic associations, including 97 that were previously unknown.
  • The research highlighted key biological pathways related to AAA, such as lipid metabolism, vascular development, and inflammation, indicating how these factors contribute to the disease's progression.
  • The study also suggests that lowering non-high-density lipoprotein cholesterol could be beneficial for AAA patients, advocating for the use of PCSK9 inhibitors based on evidence from a mouse model where PCSK9 loss prevented AAA development.
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High-throughput proteomics platforms measuring thousands of proteins in plasma combined with genomic and phenotypic information have the power to bridge the gap between the genome and diseases. Here we performed association studies of Olink Explore 3072 data generated by the UK Biobank Pharma Proteomics Project on plasma samples from more than 50,000 UK Biobank participants with phenotypic and genotypic data, stratifying on British or Irish, African and South Asian ancestries. We compared the results with those of a SomaScan v4 study on plasma from 36,000 Icelandic people, for 1,514 of whom Olink data were also available.

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Marfan syndrome (MFS) is an autosomal dominant condition characterized by aortic aneurysm, skeletal abnormalities, and lens dislocation, and is caused by variants in the FBN1 gene. To explore causes of MFS and the prevalence of the disease in Iceland we collected information from all living individuals with a clinical diagnosis of MFS in Iceland (n = 32) and performed whole-genome sequencing of those who did not have a confirmed genetic diagnosis (27/32). Moreover, to assess a potential underdiagnosis of MFS in Iceland we attempted a genotype-based approach to identify individuals with MFS.

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Conventional measurements of fasting and postprandial blood glucose levels investigated in genome-wide association studies (GWAS) cannot capture the effects of DNA variability on 'around the clock' glucoregulatory processes. Here we show that GWAS meta-analysis of glucose measurements under nonstandardized conditions (random glucose (RG)) in 476,326 individuals of diverse ancestries and without diabetes enables locus discovery and innovative pathophysiological observations. We discovered 120 RG loci represented by 150 distinct signals, including 13 with sex-dimorphic effects, two cross-ancestry and seven rare frequency signals.

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Bleeding in early pregnancy and postpartum hemorrhage (PPH) bear substantial risks, with the former closely associated with pregnancy loss and the latter being the foremost cause of maternal death, underscoring the severity of these complications in maternal-fetal health. Here, we investigated the genetic variation underlying aspects of pregnancy-associated bleeding and identified five loci associated with PPH through a meta-analysis of 21,512 cases and 259,500 controls. Functional annotation analysis indicated candidate genes, , , and / at three loci and showed that at each locus, associated variants were located within binding sites for progesterone receptors (PGR).

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Importance: Whether protein risk scores derived from a single plasma sample could be useful for risk assessment for atherosclerotic cardiovascular disease (ASCVD), in conjunction with clinical risk factors and polygenic risk scores, is uncertain.

Objective: To develop protein risk scores for ASCVD risk prediction and compare them to clinical risk factors and polygenic risk scores in primary and secondary event populations.

Design, Setting, And Participants: The primary analysis was a retrospective study of primary events among 13 540 individuals in Iceland (aged 40-75 years) with proteomics data and no history of major ASCVD events at recruitment (study duration, August 23, 2000 until October 26, 2006; follow-up through 2018).

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Background: The TNM system is used to assess prognosis after colorectal cancer (CRC) diagnosis. Other prognostic factors reported include histopathological assessments of the tumour, tumour mutations and proteins in the blood. As some of these factors are strongly correlated, it is important to evaluate the independent effects they may have on survival.

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Urticaria is a skin disorder characterized by outbreaks of raised pruritic wheals. In order to identify sequence variants associated with urticaria, we performed a meta-analysis of genome-wide association studies for urticaria with a total of 40,694 cases and 1,230,001 controls from Iceland, the UK, Finland, and Japan. We also performed transcriptome- and proteome-wide analyses in Iceland and the UK.

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Background: Persistent symptoms are common after SARS-CoV-2 infection but correlation with objective measures is unclear.

Methods: We invited all 3098 adults who tested SARS-CoV-2 positive in Iceland before October 2020 to the deCODE Health Study. We compared multiple symptoms and physical measures between 1706 Icelanders with confirmed prior infection (cases) who participated, and 619 contemporary and 13,779 historical controls.

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Microsatellites are polymorphic tracts of short tandem repeats with one to six base-pair (bp) motifs and are some of the most polymorphic variants in the genome. Using 6084 Icelandic parent-offspring trios we estimate 63.7 (95% CI: 61.

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Genotypes causing pregnancy loss and perinatal mortality are depleted among living individuals and are therefore difficult to find. To explore genetic causes of recessive lethality, we searched for sequence variants with deficit of homozygosity among 1.52 million individuals from six European populations.

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