Publications by authors named "Gudmundur Einarsson"

Although information from real-world data can be used to identify factors that aid treatment choice, there are no guidelines for the use of such data. The aim of this Review is to summarise and evaluate definitions of treatment outcomes for antidepressants, antipsychotics, and mood stabilisers when using real-world data, and to suggest standards for the field. Given that no standards for the use of these data in estimating treatment outcomes exist, variability is high for treatment outcome definitions.

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Bipolar disorder is a highly heritable psychiatric disorder; genome-wide association studies of bipolar disorder have yielded over 60 risk loci harboring common variants. To harness the information contained in rare loss-of-function (LOF) variants, holding promise for informing on the underlying biology, we performed a variant burden analysis for bipolar disorder using gene-based aggregation of LOF variants in whole-genome sequencing data from Iceland (4,197 cases, more than 200,000 controls) and the UK Biobank (1,881 cases, 426,622 controls). We found that HECTD2 was associated with bipolar disorder and confirmed it using the Bipolar Exome dataset.

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Obesity is associated with adverse effects on health and quality of life. Improved understanding of its underlying pathophysiology is essential for developing counteractive measures. To search for sequence variants with large effects on BMI, we perform a multi-ancestry meta-analysis of 13 genome-wide association studies on BMI, including data derived from 1,534,555 individuals of European ancestry, 339,657 of Asian ancestry, and 130,968 of African ancestry.

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Antidepressants exhibit a considerable variation in efficacy, and increasing evidence suggests that individual genetics contribute to antidepressant treatment response. Here, we combined data on antidepressant non-response measured using rating scales for depressive symptoms, questionnaires of treatment effect, and data from electronic health records, to increase statistical power to detect genomic loci associated with non-response to antidepressants in a total sample of 135,471 individuals prescribed antidepressants (25,255 non-responders and 110,216 responders). We performed genome-wide association meta-analyses, genetic correlation analyses, leave-one-out polygenic prediction, and bioinformatics analyses for genetically informed drug prioritization.

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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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Background: Signal transducer and activator of transcription 6 (STAT6) is central to type 2 (T2) inflammation, and common noncoding variants at the STAT6 locus associate with various T2 inflammatory traits, including diseases, and its pathway is widely targeted in asthma treatment.

Objective: We sought to test the association of a rare missense variant in STAT6, p.L406P, with T2 inflammatory traits, including the risk of asthma and allergic diseases, and to characterize its functional consequences in cell culture.

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Article Synopsis
  • Antidepressant effectiveness varies significantly among individuals, with genetics playing a role in how people respond to treatment.
  • A study analyzing data from 135,471 patients identified two new genetic locations (loci) linked to antidepressant non-response and confirmed the ability to predict treatment response using genetic information.
  • The research also explored potential new drug options that could help individuals who don't respond to traditional first-line antidepressants, highlighting the importance of larger sample studies for discovering relevant genetic factors.
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Genomic prediction of antipsychotic dose and polypharmacy has been difficult, mainly due to limited access to large cohorts with genetic and drug prescription data. In this proof of principle study, we investigated if genetic liability for schizophrenia is associated with high dose requirements of antipsychotics and antipsychotic polypharmacy, using real-world registry and biobank data from five independent Nordic cohorts of a total of N = 21,572 individuals with psychotic disorders (schizophrenia, bipolar disorder, and other psychosis). Within regression models, a polygenic risk score (PRS) for schizophrenia was studied in relation to standardized antipsychotic dose as well as antipsychotic polypharmacy, defined based on longitudinal prescription registry data as well as health records and self-reported data.

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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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Many sequence variants have additive effects on blood lipid levels and, through that, on the risk of coronary artery disease (CAD). We show that variants also have non-additive effects and interact to affect lipid levels as well as affecting variance and correlations. Variance and correlation effects are often signatures of epistasis or gene-environmental interactions.

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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: 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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  • Intracranial volume (ICV), measured through MRI or head circumference, is hereditary and linked to cognitive abilities and neurological disorders.
  • A genome-wide association study identified 64 genetic variants associated with ICV, explaining about 5% of its variation and pointing to 12 key genes involved in cranial conditions.
  • The study found that ICV is connected to brain region sizes and various traits, with Parkinson's disease linked to larger ICV and attention deficit hyperactivity disorder (ADHD) associated with smaller ICV.
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Opioid addiction (OA) is moderately heritable, yet only rs1799971, the A118G variant in OPRM1, has been identified as a genome-wide significant association with OA and independently replicated. We applied genomic structural equation modeling to conduct a GWAS of the new Genetics of Opioid Addiction Consortium (GENOA) data together with published studies (Psychiatric Genomics Consortium, Million Veteran Program, and Partners Health), comprising 23,367 cases and effective sample size of 88,114 individuals of European ancestry. Genetic correlations among the various OA phenotypes were uniformly high (r > 0.

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  • Carpal tunnel syndrome (CTS) is the most common nerve entrapment issue, and the biological reasons behind it are still not fully understood.
  • A large study involving nearly 50,000 CTS cases identified 53 genetic variants linked to the condition, with a specific gene variant (p.Glu366Lys in SERPINA1) showing protective effects against CTS.
  • The research indicates that CTS risk is influenced by 22 genes and highlights the extracellular matrix's importance, along with the genetic connections to traits like height and BMI, as well as factors such as hormonal therapy and osteoarthritis.
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  • Back pain is prevalent and complex, with this study exploring its genetic links through a genome-wide association approach involving nearly 120,000 cases of dorsalgia and about 59,000 of intervertebral disc disorder.
  • Researchers identified 41 genetic variants across 33 different locations, with the strongest correlation to a specific variant in the CHST3 gene that impacts intervertebral discs.
  • The study highlights that certain rare loss-of-function variants in the SLC13A1 gene may contribute significantly to intervertebral disc disorders, pointing to genetic factors that influence cartilage, bone health, and related inflammatory processes.
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Current assessments of motor symptoms in Parkinson's disease are often limited to clinical rating scales. To develop a computer application using the Microsoft Kinect sensor to assess performance-related bradykinesia. The developed application () was tested in patients with Parkinson's disease and healthy controls.

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Background: The assessment of motor disturbances in antipsychotic-treated adolescent patients is often limited to the use of observer-based rating scales with interobserver variability. The objectives of this pilot study were to measure movement patterns associated with antipsychotic-induced parkinsonism in young patients with psychosis and initiating/treated with antipsychotics, using a computer application connected with the Microsoft Kinect sensor (Motorgame).

Method: All participants were assessed by neurological examination, clinical side effect rating scales (Udvalg for Kliniske Undersøgelser Side Effect Rating Scale, Barnes Akathisia Rating Scale, Simpson Angus Scale (SAS), and Abnormal Involuntary Movement Scale), and the Motorgame.

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Objective Using centralized registries in Iceland, the aim of this study was to prospectively investigate multiple risk factors for renal cell carcinoma (RCC), including occupational history. Materials and methods From the Reykjavik study database, 18,840 men and women born in the period 1907-1935 were linked with a population-based registry containing all RCCs diagnosed in Iceland from 1971 to 2005 (n = 910). From this cross-reference, altogether 225 cases were identified.

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Purpose: To examine the attitudes, practices and perceived barriers in relation to a sexual health care educational intervention among oncology health care professionals at the Landspítali-National University Hospital of Iceland.

Methods: The design was quasi experimental, pre - post test time series. A comprehensive educational intervention project, including two workshops, was implemented over a two year time period.

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Transcriptional and splicing anomalies have been observed in intron 8 of the CASP8 gene (encoding procaspase-8) in association with cutaneous basal-cell carcinoma (BCC) and linked to a germline SNP rs700635. Here, we show that the rs700635[C] allele, which is associated with increased risk of BCC and breast cancer, is protective against prostate cancer [odds ratio (OR) = 0.91, P = 1.

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