Publications by authors named "Michael C Mahaney"

Article Synopsis
  • Coronary artery calcification (CAC) is linked to heart disease and assessed through a genome-wide association study (GWAS) involving 22,400 participants from various backgrounds.
  • The study confirmed connections with four known genetic loci and discovered two new loci related to CAC, with supportive replication findings for both.
  • Functional tests suggest that ARSE promotes calcification in vascular smooth muscle cells and its variants may influence CAC levels, identifying ARSE as a key target for potential treatments in vascular calcific diseases.
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Socioeconomic Status (SES) is a potent environmental determinant of health. To our knowledge, no assessment of genotype-environment interaction has been conducted to consider the joint effects of socioeconomic status and genetics on risk for metabolic disease. We analyzed data from the Mexican American Family Studies (MAFS) to evaluate the hypothesis that genotype-by-environment interaction (GxE) is an essential determinant of variation in risk factors for metabolic syndrome (MS).

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Background: Individuals with type 2 diabetes (T2D) have an increased risk of coronary artery disease (CAD), but questions remain about the underlying pathology. Identifying which CAD loci are modified by T2D in the development of subclinical atherosclerosis (coronary artery calcification [CAC], carotid intima-media thickness, or carotid plaque) may improve our understanding of the mechanisms leading to the increased CAD in T2D.

Methods: We compared the common and rare variant associations of known CAD loci from the literature on CAC, carotid intima-media thickness, and carotid plaque in up to 29 670 participants, including up to 24 157 normoglycemic controls and 5513 T2D cases leveraging whole-genome sequencing data from the Trans-Omics for Precision Medicine program.

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Article Synopsis
  • Large-scale whole-genome sequencing (WGS) studies have enhanced our understanding of how rare genetic variants affect complex human traits through better analysis techniques.* -
  • Current methods for analyzing multiple traits are limited in their ability to handle rare variants in large WGS datasets, prompting the development of MultiSTAAR.* -
  • MultiSTAAR enables more powerful analysis by considering relatedness, population structure, and the correlation between traits, leading to the discovery of new genetic associations in lipid traits that single-trait analyses missed.*
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  • Long non-coding RNAs (lncRNAs) play crucial roles in regulating lipid metabolism and have been studied in relation to genetic variants and complex traits.
  • This research utilized high-coverage whole-genome sequencing of over 66,000 diverse participants to assess how rare variants in lncRNA genes affect blood lipid levels, using a statistical framework to analyze the associations.
  • The study found 83 lncRNA variants significantly linked to lipid levels, with many being independent of common genetic variations, and replicated a majority of these findings with data from another large cohort.
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Article Synopsis
  • * Using data from the Mexican American Family Studies (MAFS), the researchers applied a linear mixed model to analyze how education levels, household income, and socioeconomic indices correlate with CVD indicators like Framingham Risk Scores and carotid artery intima-media thickness.
  • * The findings suggest that the genetic factors related to CVD are significantly influenced by education, indicating that lower SES may alter the genetic risk for CVD, unlike household income and socioeconomic index, which showed no such interaction.
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  • The study investigates the role of CCR2, a receptor for CCL2 involved in monocyte movement, in the risk of atherosclerotic cardiovascular disease, particularly through examining genetic variants in a large population sample from the UK Biobank.
  • Researchers identified 45 harmful genetic variants linked to lower monocyte counts, finding that carriers had a reduced risk of myocardial infarction and coronary artery disease, especially the M249K variant.
  • The M249K variant was associated with significantly lower risks for heart issues without increasing infection risk, suggesting its potential protective role against cardiovascular diseases.
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A bidirectional communication exists between the brain and the gut, in which the gut microbiota influences cognitive function and vice-versa. Gut dysbiosis has been linked to several diseases, including Alzheimer's disease and related dementias (ADRD). However, the relationship between gut dysbiosis and markers of cerebral small vessel disease (cSVD), a major contributor to ADRD, is unknown.

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Article Synopsis
  • Long non-coding RNAs (lncRNAs) play key roles in regulating biological functions, and new genomic studies allow researchers to explore their connection to complex traits, like blood lipid levels.
  • This research involved high-coverage whole genome sequencing from over 66,000 participants, focusing on the influence of rare variants in 165,375 lncRNA genes on lipid variability.
  • The study found 83 rare lncRNA variant sets linked to blood lipid levels, with many of these associations being independent of common variants, suggesting potential new avenues for therapeutic interventions.
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Advances in genetics and developmental biology are revealing the relationship between genotype and dental phenotype (G:P), providing new approaches for how paleontologists assess dental variation in the fossil record. Our aim was to understand how the method of trait definition influences the ability to reconstruct phylogenetic relationships and evolutionary history in the Cercopithecidae, the Linnaean Family of monkeys currently living in Africa and Asia. We compared the two-dimensional assessment of molar size (calculated as the mesiodistal length of the crown multiplied by the buccolingual breadth) to a trait that reflects developmental influences on molar development (the inhibitory cascade, IC) and two traits that reflect the genetic architecture of postcanine tooth size variation (defined through quantitative genetic analyses: MMC and PMM).

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The purpose of this study was to identify molecular mechanisms by which the liver influences total lesion burden in a nonhuman primate model (NHP) of cardiovascular disease with acute and chronic feeding of a high cholesterol, high fat (HCHF) diet. Baboons (47 females, 64 males) were fed a HCHF diet for 2 years (y); liver biopsies were collected at baseline, 7 weeks (w) and 2y, and lesions were quantified in aortic arch, descending aorta, and common iliac at 2y. Unbiased weighted gene co-expression network analysis (WGCNA) revealed several modules of hepatic genes correlated with lesions at different time points of dietary challenge.

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Patterns of genetic variation and covariation impact the evolution of the craniofacial complex and contribute to clinically significant malocclusions in modern human populations. Previous quantitative genetic studies have estimated the heritabilities and genetic correlations of skeletal and dental traits in humans and nonhuman primates, but none have estimated these quantitative genetic parameters across the dentognathic complex. A large and powerful pedigree from the Jirel population of Nepal was leveraged to estimate heritabilities and genetic correlations in 62 maxillary and mandibular arch dimensions, incisor and canine lengths, and post-canine tooth crown areas (N ≥ 739).

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Background: The identification and understanding of therapeutic targets for atherosclerotic cardiovascular disease is of fundamental importance given its global health and economic burden. Inhibition of ANGPTL3 (angiopoietin-like 3) has demonstrated a cardioprotective effect, showing promise for atherosclerotic cardiovascular disease treatment, and is currently the focus of ongoing clinical trials. Here, we assessed the genetic basis of variation in ANGPTL3 levels in the San Antonio Family Heart Study.

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Large-scale whole-genome sequencing studies have enabled the analysis of rare variants (RVs) associated with complex phenotypes. Commonly used RV association tests have limited scope to leverage variant functions. We propose STAAR (variant-set test for association using annotation information), a scalable and powerful RV association test method that effectively incorporates both variant categories and multiple complementary annotations using a dynamic weighting scheme.

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Reported associations between leukocyte telomere length (LTL) attrition, diet and cardiovascular disease (CVD) are inconsistent. This study explores effects of prolonged exposure to a high cholesterol high fat (HCHF) diet on LTL in a baboon model of atherosclerosis. We measured LTL by qPCR in pedigreed baboons fed a chow (n = 105) or HCHF (n = 106) diet for 2 years, tested for effects of diet on LTL, and association between CVD risk factors and atherosclerotic lesions with LTL.

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The de novo ceramide synthesis pathway is essential to human biology and health, but genetic influences remain unexplored. The core function of this pathway is the generation of biologically active ceramide from its precursor, dihydroceramide. Dihydroceramides have diverse, often protective, biological roles; conversely, increased ceramide levels are biomarkers of complex disease.

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Atherosclerotic plaques are characterized by an accumulation of macrophages, lipids, smooth muscle cells, and fibroblasts, and, in advanced stages, necrotic debris within the arterial walls. Dietary habits such as high fat and high cholesterol (HFHC) consumption are known risk factors for atherosclerosis. However, the key metabolic contributors to diet-induced atherosclerosis are far from established.

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Objectives: Determining the genetic architecture of quantitative traits and genetic correlations among them is important for understanding morphological evolution patterns. We address two questions regarding papionin evolution: (1) what effect do body and cranial size, age, and sex have on phenotypic (V ) and additive genetic (V ) variation in baboon crania, and (2) how might additive genetic correlations between craniofacial traits and body mass affect morphological evolution?

Materials And Methods: We use a large captive pedigreed baboon sample to estimate quantitative genetic parameters for craniofacial dimensions (EIDs). Our models include nested combinations of the covariates listed above.

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Aims: The recent failures of HDL-raising therapies have underscored our incomplete understanding of HDL biology. Therefore there is an urgent need to comprehensively investigate HDL metabolism to enable the development of effective HDL-centric therapies. To identify novel regulators of HDL metabolism, we performed a joint analysis of human genetic, transcriptomic, and plasma HDL-cholesterol (HDL-C) concentration data and identified a novel association between trafficking protein, kinesin binding 2 (TRAK2) and HDL-C concentration.

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Background: The purpose of this study was to determine whether dietary manipulation can reliably induce early-stage atherosclerosis and clinically relevant changes in vascular function in an established, well-characterized non-human primate model.

Methods: We fed 112 baboons a high-cholesterol, high-fat challenge diet for two years. We assayed circulating biomarkers of cardiovascular disease (CVD) risk, at 0, 7, and 104 weeks into the challenge; assessed arterial compliance noninvasively at 104 weeks; and measured atherosclerotic lesions in three major arteries at necropsy.

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Background: Differential plasma concentrations of circulating lipid species are associated with pathogenesis of type 2 diabetes (T2D). Whether the wide inter-individual variability in the plasma lipidome contributes to the genetic basis of T2D is unknown. Here, we investigated the potential overlap in the genetic basis of the plasma lipidome and T2D-related traits.

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encodes zinc transporter 8 which is involved in packaging and release of insulin. Evidence for the association of variants with type 2 diabetes (T2D) is inconclusive. We interrogated single nucleotide polymorphisms (SNPs) around for association with T2D in high-risk, pedigreed individuals from extended Mexican American families.

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Developmental genetics research on mice provides a relatively sound understanding of the genes necessary and sufficient to make mammalian teeth. However, mouse dentitions are highly derived compared with human dentitions, complicating the application of these insights to human biology. We used quantitative genetic analyses of data from living nonhuman primates and extensive osteological and paleontological collections to refine our assessment of dental phenotypes so that they better represent how the underlying genetic mechanisms actually influence anatomical variation.

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Background: Detection of type 2 diabetes (T2D) is routinely based on the presence of dysglycemia. Although disturbed lipid metabolism is a hallmark of T2D, the potential of plasma lipidomics as a biomarker of future T2D is unknown. Our objective was to develop and validate a plasma lipidomic risk score (LRS) as a biomarker of future type 2 diabetes and to evaluate its cost-effectiveness for T2D screening.

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