Publications by authors named "Olafur Stefansson"

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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  • Essential tremor (ET) is a common neurological disorder, but its biological causes are still not well understood.
  • A comprehensive study involving over 16,000 ET cases identified 12 genetic variants linked to the disorder, suggesting several potential causal genes, including CA3 and CPLX1.
  • The findings also reveal associations between ET and other conditions like Parkinson's disease, depression, and anxiety, which could lead to new therapeutic targets for treatment.
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Background: Long-read sequencing can enable the detection of base modifications, such as CpG methylation, in single molecules of DNA. The most commonly used methods for long-read sequencing are nanopore developed by Oxford Nanopore Technologies (ONT) and single molecule real-time (SMRT) sequencing developed by Pacific Bioscience (PacBio). In this study, we systematically compare the performance of CpG methylation detection from long-read sequencing.

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Importance: Recurrent pericarditis is a treatment challenge and often a debilitating condition. Drugs inhibiting interleukin 1 cytokines are a promising new treatment option, but their use is based on scarce biological evidence and clinical trials of modest sizes, and the contributions of innate and adaptive immune processes to the pathophysiology are incompletely understood.

Objective: To use human genomics, transcriptomics, and proteomics to shed light on the pathogenesis of pericarditis.

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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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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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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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Objectives: Erosive hand osteoarthritis (EHOA) is a severe subset of hand osteoarthritis (OA). It is unclear if EHOA is genetically different from other forms of OA. Sequence variants at ten loci have been associated with hand OA but none with EHOA.

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  • This study investigates the genetics of syncope, a common medical condition, to improve understanding of its causes and potential outcomes.
  • A large-scale analysis of genetic data from over half a million people identified 18 genetic variants linked to syncope, most of which were newly discovered, highlighting the condition's unique genetic traits.
  • The findings suggest a relationship between syncope and cardiovascular health, indicating that genetic factors related to heart rate and blood pressure regulation could be involved, reinforcing the need for careful evaluation of patients experiencing syncope.
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Detailed knowledge of how diversity in the sequence of the human genome affects phenotypic diversity depends on a comprehensive and reliable characterization of both sequences and phenotypic variation. Over the past decade, insights into this relationship have been obtained from whole-exome sequencing or whole-genome sequencing of large cohorts with rich phenotypic data. Here we describe the analysis of whole-genome sequencing of 150,119 individuals from the UK Biobank.

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Long-read sequencing (LRS) promises to improve the characterization of structural variants (SVs). We generated LRS data from 3,622 Icelanders and identified a median of 22,636 SVs per individual (a median of 13,353 insertions and 9,474 deletions). We discovered a set of 133,886 reliably genotyped SV alleles and imputed them into 166,281 individuals to explore their effects on diseases and other traits.

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Despite the important role that monozygotic twins have played in genetics research, little is known about their genomic differences. Here we show that monozygotic twins differ on average by 5.2 early developmental mutations and that approximately 15% of monozygotic twins have a substantial number of these early developmental mutations specific to one of them.

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Preeclampsia is a serious complication of pregnancy, affecting both maternal and fetal health. In genome-wide association meta-analysis of European and Central Asian mothers, we identify sequence variants that associate with preeclampsia in the maternal genome at ZNF831/20q13 and FTO/16q12. These are previously established variants for blood pressure (BP) and the FTO variant has also been associated with body mass index (BMI).

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Pelvic organ prolapse (POP) is a downward descent of one or more of the pelvic organs, resulting in a protrusion of the vaginal wall and/or uterus. We performed a genome-wide association study of POP using data from Iceland and the UK Biobank, a total of 15,010 cases with hospital-based diagnosis code and 340,734 female controls, and found eight sequence variants at seven loci associating with POP (P < 5 × 10); seven common (minor allele frequency >5%) and one with minor allele frequency of 4.87%.

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Background: Breast Cancer 1 gene () is known to be inactivated in breast tumors by promoter methylation. Tumor cells in patients carrying a germline mutation in are sensitive to cytotoxic drugs that cause DNA double strand breaks. However, very little is known on whether patients with promoter methylated tumors are similarly sensitive to cytotoxic drugs.

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Asthma is one of the most common chronic diseases affecting both children and adults. We report a genome-wide association meta-analysis of 69,189 cases and 702,199 controls from Iceland and UK biobank. We find 88 asthma risk variants at 56 loci, 19 previously unreported, and evaluate their effect on other asthma and allergic phenotypes.

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Estrogen receptor-positive breast cancer is subdivided into subtypes LuminalA and LuminalB, based on different expression patterns. MicroRNA-190b has been reported to be up-regulated in estrogen receptor-positive breast cancers. In this study we aimed to investigate the role of CpG promoter methylation in regulating miR-190b expression and its impact on clinical presentation and prognosis.

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The original HTML version of this Article was updated shortly after publication to add links to the Peer Review file.In addition, affiliations 16 and 17 incorrectly read 'School of Medicine Sydney, University of Notre Dame Australia, Sydney, WA, 6160, Australia' and 'St Vincent's Clinical School, University of New South Wales Medicine, University of New South Wales, Sydney, NSW, 2052, Australia.' This has now been corrected in both the PDF and HTML versions of the Article.

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Bone area is one measure of bone size that is easily derived from dual-energy X-ray absorptiometry (DXA) scans. In a GWA study of DXA bone area of the hip and lumbar spine (N ≥ 28,954), we find thirteen independent association signals at twelve loci that replicate in samples of European and East Asian descent (N = 13,608 - 21,277). Eight DXA area loci associate with osteoarthritis, including rs143384 in GDF5 and a missense variant in COL11A1 (rs3753841).

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Genetic diversity arises from recombination and de novo mutation (DNM). Using a combination of microarray genotype and whole-genome sequence data on parent-child pairs, we identified 4,531,535 crossover recombinations and 200,435 DNMs. The resulting genetic map has a resolution of 682 base pairs.

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In the Methods section of this Article, 'greater than' should have been 'less than' in the sentence 'Putative regions of clustered rearrangements were identified as having an average inter-rearrangement distance that was at least 10 times greater than the whole-genome average for the individual sample. '. The Article has not been corrected.

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Nasal polyps (NP) are lesions on the nasal and paranasal sinus mucosa and are a risk factor for chronic rhinosinusitis (CRS). We performed genome-wide association studies on NP and CRS in Iceland and the UK (using UK Biobank data) with 4,366 NP cases, 5,608 CRS cases, and >700,000 controls. We found 10 markers associated with NP and 2 with CRS.

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