Publications by authors named "Ritchie M"

Epidemiological data suggest the population distribution of thyrotropin (TSH) values is shifted toward lower values in self-identified Black non-Hispanic individuals compared with self-identified White non-Hispanic individuals. It is unknown whether genetic differences between individuals with genetic similarities to African reference populations (GSA) and those with similarities to European reference populations (GSE) contribute to these observed differences. We aimed to compare genome-wide associations with TSH and putative causal TSH-associated variants between GSA and GSE groups.

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Apart from ancestry, personal or environmental covariates may contribute to differences in polygenic score (PGS) performance. We analyzed the effects of covariate stratification and interaction on body mass index (BMI) PGS (PGS) across four cohorts of European (N = 491,111) and African (N = 21,612) ancestry. Stratifying on binary covariates and quintiles for continuous covariates, 18/62 covariates had significant and replicable R differences among strata.

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Single-cell long-read sequencing has transformed our understanding of isoform usage and the mutation heterogeneity between cells. Despite unbiased in-depth analysis, the low sequencing throughput often results in insufficient read coverage thereby limiting our ability to perform mutation calling for specific genes. Here, we developed a single-cell Rapid Capture Hybridization sequencing (scRaCH-seq) method that demonstrated high specificity and efficiency in capturing targeted transcripts using long-read sequencing, allowing an in-depth analysis of mutation status and transcript usage for genes of interest.

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Background/objectives: Cardiovascular disease (CVD) and Alzheimer's disease (AD) are two diseases highly prevalent in the aging population and often co-occur. The exact relationship between the two diseases is uncertain, though epidemiological studies have demonstrated that CVDs appear to increase the risk of AD and vice versa. This scoping review aims to examine the current identified overlapping genetics between CVDs and AD at the individual gene level and at the shared pathway level.

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Nonalcoholic fatty liver disease (NAFLD) is the most common global cause of chronic liver disease and remains under-recognized within healthcare systems. Therapeutic interventions are rapidly advancing for its inflammatory phenotype, nonalcoholic steatohepatitis (NASH) at all stages of disease. Diagnosis codes alone fail to recognize and stratify at-risk patients accurately.

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and are a sister species pair that have been used as a model for studies of reproductive isolation and speciation for almost 100 years owing to their close evolutionary history, well characterized genetic differences, and overlapping geographic distribution. There are extensive analyses of both pre- and post-zygotic isolation, including studies of courtship divergence, conspecific sperm precedence (CSP) and how reinforcement by natural selection may or may not act to strengthen isolation in sympatry. Post-zygotic analyses explore the underlying mechanics of reproductive isolation; how inversions may give rise to initial speciation events and misexpression of key genes typically found within inversion regions render hybrid offspring unfit or inviable.

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Polygenic risk scores (PRS) have predominantly been derived from genome-wide association studies (GWAS) conducted in European ancestry (EUR) individuals. In this study, we present an in-depth evaluation of PRS based on multi-ancestry GWAS for five cardiometabolic phenotypes in the Penn Medicine BioBank (PMBB) followed by a phenome-wide association study (PheWAS). We examine the PRS performance across all individuals and separately in African ancestry (AFR) and EUR ancestry groups.

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Gene-environment interaction (GxE) studies provide insights into the interplay between genetics and the environment but often overlook multiple environmental factors' synergistic effects. This study encompasses the use of environment by environment interaction (ExE) studies to explore interactions among environmental factors affecting lipid phenotypes (e.g.

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Heart failure (HF) is one of the most common, complex, heterogeneous diseases in the world, with over 1-3% of the global population living with the condition. Progression of HF can be tracked via MRI measures of structural and functional changes to the heart, namely left ventricle (LV), including ejection fraction, mass, end-diastolic volume, and LV end-systolic volume. Moreover, while genome-wide association studies (GWAS) have been a useful tool to identify candidate variants involved in HF risk, they lack crucial tissue-specific and mechanistic information which can be gained from incorporating additional data modalities.

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Article Synopsis
  • Investigating drug-gene targets is essential for developing better therapies for Alzheimer’s disease due to its complex nature.
  • An explainable machine learning model combines gene interactions and databases to identify novel gene-drug targets for further research.
  • The model was validated with a diverse sample from the Alzheimer's Disease Sequencing Project, using new data curation methods to ensure reliable results and suggesting targets for drug repurposing.
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Genome-wide association studies (GWAS) are an important tool for the study of complex disease genetics. Decisions regarding the quality control (QC) procedures employed as part of a GWAS can have important implications on the results and their biological interpretation. Many GWAS have been conducted predominantly in cohorts of European ancestry, but many initiatives aim to increase the representation of diverse ancestries in genetic studies.

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Pharmacogenetics represents one of the most promising areas of precision medicine, with several guidelines for genetics-guided treatment ready for clinical use. Despite this, implementation has been slow, with few health systems incorporating the technology into their standard of care. One major barrier to uptake is the lack of education and awareness of pharmacogenetics among clinicians and patients.

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The 2025 Pacific Symposium on Biocomputing (PSB) represents a remarkable milestone, as it is the thirtieth anniversary of PSB. We use this opportunity to analyze the bibliometric output of 30 years of PSB publications in a wide range of analyses with a focus on various eras that represent important disruptive breakpoints in the field of bioinformatics and biocomputing. These include an analysis of paper topics and keywords, flight emissions produced by travel to PSB by authors, citation and co-authorship networks and metrics, and a broad assessment of diversity and representation in PSB authors.

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Accurately determining the binding affinity of a ligand with a protein is important for drug design, development, and screening. With the advent of accessible protein structure prediction methods such as AlphaFold, several approaches have been developed that make use of information determined from the 3D structure for a variety of downstream tasks. However, methods for predicting binding affinity that do consider protein structure generally do not take full advantage of such 3D structural protein information, often using such information only to define nearest-neighbor graphs based on inter-residue or inter-atomic distances.

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Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most widely used medications for the management of chronic pain; however, they are associated with numerous gastrointestinal (GI) adverse events. Although many mechanisms have been suggested, NSAID-induced enteropathy has been thought to be primarily due to inhibition of both cyclooxygenases (COX) -1 and -2, which results in suppression of prostaglandin synthesis. Yet surprisingly, we found that concomitant postnatal deletion of and over 10 months failed to cause intestinal injury in mice unless they were treated with naproxen or its structural analog, phenylpropionic acid, which is not a COX inhibitor.

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Single-cell RNA sequencing (scRNA-seq) is a powerful technology that enables the measurement of gene expression in individual cells. Such precision provides insights into cellular heterogeneity that bulk methods might overlook. Fragile cells, in particular neutrophils, have posed significant challenges for scRNA-Seq due to their fragility, high RNase content and consequent loss during cryopreservation.

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Human organ structure and function are important endophenotypes for clinical outcomes. Genome-wide association studies (GWAS) have identified numerous common variants associated with phenotypes derived from magnetic resonance imaging (MRI) of the brain and body. However, the role of rare protein-coding variations affecting organ size and function is largely unknown.

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Background: Many cognitively unimpaired older adults are interested in learning their Alzheimer's disease (AD) biomarker status, but little is known about motivations to undergo biomarker testing and result disclosure in the setting of preclinical AD trials.

Objectives: Examine whether motivations to undergo AD biomarker testing and disclosure differ for individuals who have elevated amyloid compared to those with not elevated amyloid, and whether disclosure of amyloid results impacts participants' motivations.

Design, Setting, Participants: We conducted post-hoc analyses using data from the EARLY study, a preclinical AD trial of the beta-secretase inhibitor atabecestat.

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Importance: Polygenic risk scores (PRSs) for coronary heart disease (CHD) are a growing clinical and commercial reality. Whether existing scores provide similar individual-level assessments of disease susceptibility remains incompletely characterized.

Objective: To characterize the individual-level agreement of CHD PRSs that perform similarly at the population level.

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Article Synopsis
  • The study investigates the role of BAG3 genetic variants in heritable dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM), focusing on how these variants contribute to the variability in disease expression and severity.
  • Conducted at the University of Pennsylvania Health System, the research included a large cohort of patients, using whole-exome sequencing linked to electronic health records to analyze associations between BAG3 variants and clinical traits.
  • Results indicated that the common C151R BAG3 variant is linked to a lower risk of DCM but an increased risk of HCM, with carriers showing better long-term health outcomes compared to noncarriers.
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Article Synopsis
  • Venetoclax is a novel drug that improves outcomes for chronic lymphocytic leukemia (CLL) patients, showing that early treatment response can predict long-term success.
  • Researchers used mass cytometry to analyze blood samples from CLL patients and found that venetoclax significantly reduced various CLL cell subpopulations while increasing survival proteins in the remaining cells.
  • The study suggests that CLL cells quickly adapt to therapies through survival signals like the B-cell activating factor (BAFF), indicating that combining treatments might lead to more effective and lasting results.
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Article Synopsis
  • * Nanopore direct RNA sequencing was found to be the best method for detecting RNA issues, including cryptic splicing and polyadenylation sites in lentiviral vectors.
  • * This sequencing technique can help optimize vector design, leading to better quality and more reliable lentiviral gene therapies.
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Apoptotic cell death is regulated by the BCL-2 protein family, with clusters of BAK or BAX homodimers driving pore formation in the mitochondrial outer membrane via a poorly understood process. There is growing evidence that, in addition to BAK and BAX, lipids play an important role in pore formation. Towards a better understanding of the lipidic drivers of apoptotic pore formation in isolated mitochondria, two complementary approaches were taken.

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Background: Abnormalities of in utero testis development are strongly associated with reproductive health conditions, including male infertility and testis cancer. In mouse testes, SOX9 and FGF9 support Sertoli cell development, while VEGF signalling is essential for the establishment of vasculature. The mitogen-activated protein kinase (MAPK) pathway is a major signalling cascade, essential for cell proliferation, differentiation and activation of Sry during primary sex-determination, but little is known about its function during fetal testis morphogenesis.

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Background And Objective: Acute myelogenous leukemia (AML) is a common blood cancer marked by heterogeneity in disease and diverse genetic abnormalities. Additional therapies are needed as the 5-year survival remains below 30%. Trametinib is a mitogen-activated extracellular signal-regulated kinase (MEK) inhibitor that is widely used in solid tumors and also in tumors with activating RAS mutations.

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