Publications by authors named "Caroline M Nievergelt"

In recent years, significant efforts have been made to improve methods for genomic studies of admixed populations using local ancestry inference (LAI). Accurate LAI is crucial to ensure that downstream analyses accurately reflect the genetic ancestry of research participants. Here, we test analytic strategies for LAI to provide guidelines for optimal accuracy, focusing on admixed populations reflective of Latin America's primary continental ancestries-African (AFR), Amerindigenous (AMR), and European (EUR).

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  • The study explores the biological differences linked to PTSD by examining DNA methylation changes in blood, suggesting they could indicate susceptibility or effects of trauma.
  • Conducted by the Psychiatric Genomics Consortium, the research included nearly 5,100 participants to identify specific genetic markers associated with PTSD.
  • Results showed 11 significant CpG sites related to PTSD, with some also showing correlations between blood and brain tissue methylation, highlighting their potential role in understanding PTSD biology.
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Genetic contributions to human cortical structure manifest pervasive pleiotropy. This pleiotropy may be harnessed to identify unique genetically-informed parcellations of the cortex that are neurobiologically distinct from functional, cytoarchitectural, or other cortical parcellation schemes. We investigated genetic pleiotropy by applying genomic structural equation modeling (SEM) to map the genetic architecture of cortical surface area (SA) and cortical thickness (CT) for 34 brain regions recently reported in the ENIGMA cortical GWAS.

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  • Researchers aimed to create and validate Methylation Risk Scores (MRS) using machine learning to identify individuals at risk for PTSD based on genomic and trauma exposure data.
  • The study developed three models: eMRS (which combines trauma exposure and methylation data), MoRS (which relies only on methylation data), and MoRSAE (which adjusts MoRS for trauma exposure).
  • The eMRS model showed the best performance with a 92% accuracy, and all models were able to predict post-deployment PTSD significantly, suggesting that including trauma exposure improves risk assessment.
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In recent years, significant efforts have been made to improve methods for genomic studies of admixed populations using Local Ancestry Inference (LAI). Accurate LAI is crucial to ensure downstream analyses reflect the genetic ancestry of research participants accurately. Here, we test analytic strategies for LAI to provide guidelines for optimal accuracy, focusing on admixed populations reflective of Latin America's primary continental ancestries - African (AFR), Amerindigenous (AMR), and European (EUR).

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  • The study investigates the link between post-traumatic stress disorder (PTSD) and differences in DNA methylation, a type of gene regulation, in blood samples from individuals diagnosed with PTSD compared to trauma-exposed controls.
  • Researchers conducted a large-scale analysis involving over 5,000 participants from various civilian and military studies, using standardized procedures for PTSD assessment and DNA methylation testing.
  • The results revealed 11 specific DNA methylation sites associated with PTSD, and found similarities in methylation patterns between blood and brain tissues, suggesting a biological basis for the condition.
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Background: Previous epidemiological research has linked posttraumatic stress disorder (PTSD) with specific physical health problems, but the comprehensive landscape of medical conditions associated with PTSD remains uncharacterized. Electronic health records provide an opportunity to overcome clinical knowledge gaps and uncover associations with biological relevance that potentially vary by sex.

Methods: PTSD was defined among biobank participants ( = 145,959) in 3 major healthcare systems using 2 ICD code-based definitions: broad (≥1 PTSD or acute stress codes vs.

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The molecular pathology of stress-related disorders remains elusive. Our brain multiregion, multiomic study of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) included the central nucleus of the amygdala, hippocampal dentate gyrus, and medial prefrontal cortex (mPFC). Genes and exons within the mPFC carried most disease signals replicated across two independent cohorts.

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  • Bipolar disorder (BD) features disrupted sleep patterns and nerve cell loss, with lithium being a common but variably effective treatment.
  • Research focused on how certain circadian genes and their interactions influence cell survival and lithium response using neurons from BD patients and regular controls.
  • Findings indicated that certain gene knockdowns affected cell survival differently between lithium responders and non-responders, suggesting complex roles of circadian rhythms in BD and lithium treatment efficacy.
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  • PTSD genetics have been difficult to study compared to other psychiatric disorders, limiting our biological understanding of the condition.
  • A large-scale meta-analysis involving over 1.2 million individuals identified 95 genome-wide significant loci, with 80 being new discoveries related to PTSD.
  • Researchers identified 43 potential causal genes linked to neurotransmitter activity, developmental processes, synaptic function, and immune regulation, enhancing our knowledge of the neurobiological systems involved in PTSD.
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Observational studies suggest that posttraumatic stress disorder (PTSD) increases risk for various autoimmune diseases. Insights into shared biology and causal relationships between these diseases may inform intervention approaches to PTSD and co-morbid autoimmune conditions. We investigated the shared genetic contributions and causal relationships between PTSD, 18 autoimmune diseases, and 3 immune/inflammatory biomarkers.

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Importance: Migraine is a prevalent and debilitating condition that substantially impacts quality of life. Investigating migraine prevalence, associated comorbidities, and potential military service exposures in veterans, focusing on gender differences, is crucial for targeted interventions and management strategies.

Objective: To determine the prevalence of migraine, associated health comorbidities, and potential military service and environmental exposures among men and women US veterans using a large-scale epidemiological sample from the Million Veteran Program (MVP).

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  • Lithium is the primary treatment for bipolar disorder (BD), but how it works and predicts outcomes is not fully understood.
  • A previous study identified key cellular pathways linked to lithium response, including focal adhesion and PI3K-Akt signaling.
  • In this new study, researchers confirmed these pathways in a larger group of 2039 patients but found no connection with the extracellular matrix, suggesting that issues with neuronal growth signaling may impact lithium effectiveness.
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Tinnitus is a heritable, highly prevalent auditory disorder treated by multiple medical specialties. Previous GWAS indicated high genetic correlations between tinnitus and hearing loss, with little indication of differentiating signals. We present a GWAS meta-analysis, triple previous sample sizes, and expand to non-European ancestries.

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Large-scale genetic studies of traumatic brain injury (TBI) are lacking; thus, our understanding of the influence of genetic factors on TBI risk and recovery is incomplete. This study aimed to conduct a genome-wide association study (GWAS) of TBI in VA Million Veteran Program (MVP) enrollees. Participants included a multi-ancestry cohort (European, African, and Hispanic ancestries; N = 304,485; 111,494 TBI cases, 192,991 controls).

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  • PTSD genetics are harder to study compared to other mental health disorders, resulting in limited biological insights from past research.
  • A large-scale analysis involving over 1.2 million individuals found 95 significant genetic loci related to PTSD, with 80 being new discoveries.
  • The study identified 43 potential causal genes linked to neurotransmitters, synaptic function, and immune responses, enhancing understanding of PTSD's biological mechanisms and suggesting new research directions.
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Background: Prior epidemiological research has linked PTSD with specific physical health problems, but the comprehensive landscape of medical conditions associated with PTSD remains uncharacterized. Electronic health records (EHR) provide an opportunity to overcome prior clinical knowledge gaps and uncover associations with biological relevance that potentially vary by sex.

Methods: PTSD was defined among biobank participants (total N=123,365) in a major healthcare system using two ICD code-based definitions: broad (1+ PTSD or acute stress codes versus 0; N=14,899) and narrow (2+ PTSD codes versus 0; N=3,026).

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Objective: Multidisciplinary studies of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) implicate the dorsolateral prefrontal cortex (DLPFC) in disease risk and pathophysiology. Postmortem brain studies have relied on bulk-tissue RNA sequencing (RNA-seq), but single-cell RNA-seq is needed to dissect cell-type-specific mechanisms. The authors conducted the first single-nucleus RNA-seq postmortem brain study in PTSD to elucidate disease transcriptomic pathology with cell-type-specific resolution.

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Lithium is regarded as the first-line treatment for bipolar disorder (BD), a severe and disabling mental health disorder that affects about 1% of the population worldwide. Nevertheless, lithium is not consistently effective, with only 30% of patients showing a favorable response to treatment. To provide personalized treatment options for bipolar patients, it is essential to identify prediction biomarkers such as polygenic scores.

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Background: Hearing problems (HP) in adults are common and are associated with several comorbid conditions. Its prevalence increases with age, reflecting the cumulative effect of environmental factors and genetic predisposition. Although several risk loci have been already identified, HP biology and epidemiology are still insufficiently investigated by large-scale genetic studies.

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Bipolar disorder (BD) is characterized by mood episodes, disrupted circadian rhythms and gray matter reduction in the brain. Lithium is an effective pharmacotherapy for BD, but not all patients respond to treatment. Lithium has neuroprotective properties and beneficial effects on circadian rhythms that may distinguish lithium responders (Li-R) from non-responders (Li-NR).

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  • Lithium is recognized as a leading treatment for bipolar disorder, but predicting who will respond to it remains a challenge, leading researchers to investigate the genetic and functional differences between lithium responders and non-responders.
  • A study analyzing iPSC-derived neurons found 41 genes significantly expressed differently between these groups, and further gene prioritization identified over a thousand candidate genes related to lithium response.
  • The research highlighted the role of focal adhesion and the extracellular matrix in response mechanisms, indicating that differences in these areas may have a more significant impact on lithium treatment efficacy than the drug itself.
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