Publications by authors named "Timothy D O Connor"

Socioeconomic Position (SEP) is a multidimensional construct encompassing education, income, occupation, and neighborhood distress, influencing chronic pain severity, interference, and duration. However, its impact on placebo analgesia, where reduced pain perception occurs due to treatment belief, remains understudied. Using a quasi-experimental approach, we investigated SEP's influence on placebo analgesia in 401 participants with temporomandibular disorder (TMD) and 400 pain-free individuals.

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  • Latin Americans are often overlooked in genetic studies, which can widen gaps in personalized medicine due to the challenges of accessing genetic data and consent processes.
  • The Genetics of Latin American Diversity (GLAD) Project compiles genetic information from over 53,000 individuals across various regions to explore diverse ancestry and gene flow in the Americas.
  • GLAD includes a tool called GLAD-match to align external genetic samples with its database while protecting individual privacy, thus supporting more inclusive genomic research and enhancing personalized medicine for Latin Americans.
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More globally diverse perspectives are needed in genomic studies and precision medicine practices on non-Europeans. Here, we illustrate this by discussing the distribution of clinically actionable genetic variants involved in drug response in Andean highlanders and Amazonians, considering their environment, history, genetic structure, and historical biases in the perception of biological diversity of Native Americans.

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Motivation: Deep generative models have the potential to overcome difficulties in sharing individual-level genomic data by producing synthetic genomes that preserve the genomic associations specific to a cohort while not violating the privacy of any individual cohort member. However, there is significant room for improvement in the fidelity and usability of existing synthetic genome approaches.

Results: We demonstrate that when combined with plentiful data and with population-specific selection criteria, deep generative models can produce synthetic genomes and cohorts that closely model the original populations.

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, , and are three of the most widespread vectors of malaria parasites, with geographical ranges stretching across wide swaths of Africa. Understanding the population structure of these closely related species, including the extent to which populations are connected by gene flow, is essential for understanding how vector control implemented in one location might indirectly affect vector populations in other locations. Here, we assessed the population structure of each species based on a combined data set of publicly available and newly processed whole-genome sequences.

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Genomic surveillance is crucial for identifying at-risk populations for targeted malaria control and elimination. Identity-by-descent (IBD) is increasingly being used in population genomics to estimate genetic relatedness, effective population size ( ), population structure, and signals of positive selection. Despite its potential, a thorough evaluation of IBD segment detection tools for species with high recombination rates, such as , remains absent.

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  • Genome-wide association studies have identified genetic risk factors but often rely on imputation panels that mainly represent European ancestry, affecting quality in underrepresented groups like Latin Americans.
  • This study examines how altering the composition of imputation reference panels impacts imputation quality in four different Latin American cohorts, specifically analyzing chromosomes 7 and X.
  • Results show that increasing the number of Latin Americans in the reference leads to better imputation quality, while excluding them, as well as adjustments in European and African representation, affects quality differently across populations and chromosomes.
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Malaria genomic surveillance often estimates parasite genetic relatedness using metrics such as Identity-By-Decent (IBD), yet strong positive selection stemming from antimalarial drug resistance or other interventions may bias IBD-based estimates. In this study, we use simulations, a true IBD inference algorithm, and empirical data sets from different malaria transmission settings to investigate the extent of this bias and explore potential correction strategies. We analyze whole genome sequence data generated from 640 new and 3089 publicly available Plasmodium falciparum clinical isolates.

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Purpose: We investigated racial disparities in survival by histology in cervical cancer and examined the factors contributing to these disparities.

Methods: Non-Hispanic Black and non-Hispanic White (hereafter known as Black and White) patients with stage I-IV cervical carcinoma diagnosed between 2004 and 2017 in the National Cancer Database were studied. Survival differences were compared using Cox modeling to estimate hazard ratio (HR) or adjusted HR (AHR) and 95% confidence interval (CI).

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Objective: This study investigated the risk of an aggressive endometrial cancer (EC) diagnosis by race, ethnicity, and country of origin to further elucidate histologic disparities in non-Hispanic Black (NHB), Hispanic, Asian/Pacific Islander (API), American Indian/Alaskan Native (AIAN) vs. non-Hispanic White (NHW) patients, particularly in Hispanic or API subgroups.

Methods: Patient diagnosed between 2004 and 2020 with low grade (LG)-endometrioid endometrial cancer (ECC) or an aggressive EC including grade 3 EEC, serous carcinoma, clear cell carcinoma, mixed epithelial carcinoma, or carcinosarcoma in the National Cancer Database were studied.

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  • Omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) are important for human health, and previous studies have identified strong genetic signals related to these fats in a specific gene region called FADS among European Americans.
  • A new genome-wide association study (GWAS) was conducted with Hispanic American and African American participants to explore genetic signals for n-3 and n-6 PUFAs, confirming the FADS association and finding additional signals nearby in the DAGLA and BEST1 genes.
  • Notably, the study discovered unique genetic associations related to arachidonic acid in Hispanic Americans, including a specific genetic variant in the POLD4 gene that is common in this group but absent in others, highlighting the
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Malaria genomic surveillance often estimates parasite genetic relatedness using metrics such as Identity-By-Decent (IBD). Yet, strong positive selection stemming from antimalarial drug resistance or other interventions may bias IBD-based estimates. In this study, we utilized simulations, a true IBD inference algorithm, and empirical datasets from different malaria transmission settings to investigate the extent of such bias and explore potential correction strategies.

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Background: Sex differences in Parkinson's disease (PD) risk are well-known. However, the role of sex chromosomes in the development and progression of PD is still unclear.

Objective: The objective of this study was to perform the first X-chromosome-wide association study for PD risk in a Latin American cohort.

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Importance: Disparities in survival exist between non-Hispanic Black (hereafter, Black) and non-Hispanic White (hereafter, White) patients with uterine cancer.

Objective: To investigate factors associated with racial disparities in survival between Black and White patients with uterine cancer.

Design, Setting, And Patients: This cohort study used data from the National Cancer Database on 274 838 Black and White patients who received a diagnosis of uterine cancer from January 1, 2004, to December 31, 2017, with follow-up through December 2020.

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Sex differences in Parkinson Disease (PD) risk are well-known. However, it is still unclear the role of sex chromosomes in the development and progression of PD. We performed the first X-chromosome Wide Association Study (XWAS) for PD risk in Latin American individuals.

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Recent genome wide association studies have identified 89 common genetic variants robustly associated with ischemic stroke and primarily located in non-coding regions. To evaluate the contribution of coding variants, which are mostly rare, we performed an exome array analysis on 106,101 SNPs for 9721 ischemic stroke cases from the SiGN Consortium, and 12,345 subjects with no history of stroke from the Health Retirement Study and SiGN consortium. We identified 15 coding variants significantly associated with all ischemic stroke at array-wide threshold (i.

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  • The study investigates genetic variants linked to early-onset ischemic stroke (EOS) in individuals aged 18-59, contrasting with previous research focused on late-onset stroke (LOS).
  • Researchers conducted a meta-analysis involving 16,730 EOS cases and 599,237 controls to identify significant genetic associations and compared results between EOS and LOS.
  • Findings include two genetic variants associated with blood subgroups that show a stronger connection to EOS than LOS, indicating that genetic factors promoting blood clotting are particularly influential in early-onset cases.
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  • Previous Parkinson's disease genome-wide association studies (GWAS) focused mainly on individuals of European ancestry, resulting in polygenic risk scores (PRS) that may not accurately predict PD risk in non-European populations.
  • In this study, a PD PRS was developed specifically for a Latino cohort and validated using data from independent Latino subjects and additional Peruvian controls, which showed varying predictive strengths.
  • Findings indicate that while the PRS shows promise for predicting PD risk among Latinos, differences in genetic ancestry and the limitations of relying on European data highlight the need for more inclusive research to refine risk prediction across diverse populations.
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PDE4B (phosphodiesterase-4B) has an important role in cancer and in pharmacology of some disorders, such as inflammatory diseases. Remarkably in Native Americans, PDE4B variants are associated with acute lymphoblastic leukemia (ALL) relapse, as this gene modulates sensitivity of glucocorticoids used in ALL chemotherapy. PDE4B allele rs6683977.

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Human diets in developed countries such as the US have changed dramatically over the past 75 years, leading to increased obesity, inflammation, and cardiometabolic dysfunction. Evidence over the past decade indicates that the interaction of genetic variation with changes in the intake of 18-carbon essential dietary omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFA), linoleic acid (LA) and α-linolenic acid (ALA), respectively, has impacted numerous molecular and clinical phenotypes. Interactions are particularly relevant with the and genes, which encode key fatty acid desaturases in the pathway that converts LA and ALA to their long chain (≥20 carbons), highly unsaturated fatty acid (HUFA) counterparts.

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Characterization of ancestry-linked peptide variants in disease-relevant patient tissues represents a foundational step to connect patient ancestry with disease pathogenesis. Nonsynonymous single-nucleotide polymorphisms encoding missense substitutions within tryptic peptides exhibiting high allele frequencies in European, African, and East Asian populations, termed peptide ancestry informative markers (pAIMs), were prioritized from 1000 genomes. analysis identified that as few as 20 pAIMs can determine ancestry proportions similarly to >260K SNPs (R = 0.

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Background: RIFINs and STEVORs are variant surface antigens expressed by P. falciparum that play roles in severe malaria pathogenesis and immune evasion. These two highly diverse multigene families feature multiple paralogs, making their classification challenging using traditional bioinformatic methods.

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In adulthood, the ability to digest lactose, the main sugar present in milk of mammals, is a phenotype (lactase persistence) observed in historically herder populations, mainly Northern Europeans, Eastern Africans, and Middle Eastern nomads. As the allele in the gene is the most well-characterized allele responsible for the lactase persistence phenotype, the > (rs4988235) polymorphism is commonly evaluated in lactase persistence studies. Lactase non-persistent adults may develop symptoms of lactose intolerance when consuming dairy products.

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For human/SARS-CoV-2 interactome genes ACE2, TMPRSS2 and BSG, there is a convincing evidence of association in Asians with influenza-induced SARS for TMPRSS2-rs2070788, tag-SNP of the eQTL rs383510. This case illustrates the importance of population genetics and of sequencing data in the design of genetic association studies in different human populations: the high linkage disequilibrium (LD) between rs2070788 and rs383510 is Asian-specific. Leveraging on a combination of genotyping and sequencing data for Native Americans (neglected in genetic studies), we show that while their frequencies of the Asian tag-SNP rs2070788 is, surprisingly, the highest worldwide, it is not in LD with the eQTL rs383510, that therefore, should be directly genotyped in genetic association studies of SARS in populations with Native American ancestry.

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  • - Biological mechanisms behind human germline mutations are not well understood, but recent analysis has identified nine processes that influence mutation rates and types through a deep dive into genomic variation.
  • - Using data from a large sequencing study (TOPMed), researchers interpreted seven of these processes, linking them to factors like DNA damage resolution and the effects of DNA replication timing and direction.
  • - They discovered specific mutagenic effects related to DNA regulation and certain DNA elements, highlighting a unique mutagenic process in oocytes that shows transcriptional asymmetry.
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