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Genetic Association Studies

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Genetic Association Studies are research investigations that explore the relationship between genetic variations, such as single nucleotide polymorphisms (SNPs), and specific traits or diseases in populations. These studies aim to identify genetic factors that contribute to phenotypic differences and susceptibility to various health conditions.
lightbulbAbout this topic
Genetic Association Studies are research investigations that explore the relationship between genetic variations, such as single nucleotide polymorphisms (SNPs), and specific traits or diseases in populations. These studies aim to identify genetic factors that contribute to phenotypic differences and susceptibility to various health conditions.

Key research themes

1. How can meta-analysis and specialized software improve the reliability and reproducibility of genetic association study results?

Genetic association studies often suffer from low reproducibility due to experimental design flaws, small sample sizes, population stratification, and other biases. Meta-analysis techniques synthesize results across studies to increase statistical power and resolve conflicting findings. Dedicated software tailored for genetic association studies can standardize quality control checks (e.g., Hardy-Weinberg equilibrium), model different genetic inheritance modes, and automate heterogeneity and publication bias assessments to reduce analytical errors and enhance reproducibility.

Key finding: MetaGenyo provides a user-friendly, comprehensive workflow specifically designed for the meta-analysis of genetic association studies. It includes modules for Hardy-Weinberg equilibrium testing, multiple genetic models... Read more
Key finding: This work highlights the critical steps for quality control (QC) in GWAS data, emphasizing the importance of filtering for allele frequency, missingness, heterozygosity, sex discrepancies, and population structure. The... Read more
Key finding: The study compares multiple linear mixed model implementations (EMMAX, FaST-LMM, Gemma, GenABEL) that account for relatedness in GWAS data. All methods reduce inflation due to population structure and familial relationships... Read more

2. What are the methodological advancements and statistical models for improved detection of genetic associations in complex traits considering sample structure, polygenic effects, and multiple variants?

Genetic association analyses must account for complex sample relatedness (family, population stratification), polygenic architecture, and multi-variant effects to improve power and reduce false positives. Linear mixed models and Bayesian random effects frameworks have been developed to jointly model genotypes and phenotypes, allowing flexible priors (e.g., Gaussian, heavy-tailed) and variable selection. Also, multi-marker and multi-trait models facilitate detection of smaller signals and biological networks influencing traits, addressing limitations of single-variant tests. These advances improve inference precision, especially in admixed or family-based cohorts.

Key finding: The study compares frequentist and Bayesian approaches (Gaussian, BayesA heavy-tailed, and stochastic search variable selection [SSVS]) in genome-wide association using random effects models. Bayesian sparse priors and... Read more
Key finding: This study develops linear mixed models (LMMs) and functional LMMs (FLMMs) for association testing of rare and common variants, incorporating pedigree structures and kinship coefficients. FLMMs effectively model genetic... Read more
Key finding: The authors propose QTCAT, a multi-marker association test that models correlation among markers, thereby eliminating the need for explicit population structure correction via random effects. By simultaneously associating... Read more
Key finding: A novel statistical method is proposed for joint analysis of multiple phenotypes and multiple genetic variants in family-based samples. The approach is robust to population substructure and increases power over traditional... Read more

3. How can genetic ancestry and admixture mapping be integrated in association studies to improve detection power and control for population stratification in admixed populations?

Admixed populations pose challenges for GWAS because population structure and linkage disequilibrium patterns differ across ancestries, potentially masking or confounding associations. Incorporating global and local ancestry into association testing improves power and controls confounding. Methods have been developed to jointly model genotype and locus-specific ancestry, accounting for admixture linkage disequilibrium and complex correlation structures. These methods enable multi-locus modeling and interaction testing in admixed populations, facilitating the discovery of population-specific genetic effects and elucidating genetic contributions to trait variability across ancestries.

Key finding: This work extends single-marker joint genotype- and locus-specific ancestry tests to multi-locus models for admixed populations by modifying Bayesian Information Criterion approaches (e.g., mBIC2) that account for linkage... Read more
Key finding: The authors introduce asaMap, a statistical method allowing for ancestry-specific effect sizes in GWAS of recently admixed populations. Unlike methods assuming uniform effects across ancestries, asaMap models local ancestry... Read more
Key finding: This review surveys global and local ancestry estimation methods and highlights their biomedical applications, including admixture mapping studies to identify disease-associated loci in admixed populations. It emphasizes how... Read more

All papers in Genetic Association Studies

Accurate diagnosis of rare inherited anaemias is challenging, requiring a series of complex and expensive laboratory tests. Targeted next-generation-sequencing (NGS) has been used to investigate these disorders, but the selection of genes... more
Purpose: To investigate whether variants in a set of eight candidate genes are associated with diabetic retinopathy (DR) in a cohort of Chinese patients with type 2 diabetes mellitus (T2DM). Methods: Case-control study. Patients with T2DM... more
Azathioprine (AZA), a synthetic purine analog, has remained a cornerstone in immunosuppressive therapy for over half a century. Initially approved by the U.S. Food and Drug Administration (FDA) for active rheumatoid arthritis and as... more
Background. The aim of our work was to replicate, in a Southern European population, the association reported in Northern populations betweenPTPRClocus and response to anti-tumor necrosis factor (anti-TNF) treatment in rheumatoid... more
Although attention-deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental condition, there is also considerable scientific and public interest in environmental modulators of its etiology. Exposure to neurotoxins is one... more
Genetic influences on dopaminergic neurotransmission have been implicated in attention-deficit hyperactivity disorder (ADHD) and are theorized to impact cognitive functioning via alterations in frontal-striatal circuitry.... more
Although attention-deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental condition, there is also considerable scientific and public interest in environmental modulators of its etiology. Exposure to neurotoxins is one... more
Deletions of the HOXC gene cluster result in variable phenotypes in mice, but have been rarely described in humans. To report chromosome 12q13.13 microdeletions ranging from 13 to 175 kb and involving the 5' HOXC genes in four... more
SummaryThe diagnosis of von Willebrand disease (VWD) remains difficult in a significant proportion of patients. A Spanish multicentre study investigated a cohort of 556 patients from 330 families who were analysed centrally. VWD was... more
Se realizó un estudio analítico no experimental de corte transversal con casos y controles en el policlínico Josué País García del municipio Santiago de Cuba, a partir de 100 individuos de ellos 30 con diagnóstico clínico de depresión y... more
Nowadays, genome-wide association studies (GWAS) and genomic selection (GS) methods which use genome-wide marker data for phenotype prediction are of much potential interest in plant breeding. However, to our knowledge, no studies have... more
The programmed cell death 1 (PDCD1) gene encodes for the PD-1 (programmed death 1) molecule, which negatively regulates self-reactive T-and B-cells in the maintenance of peripheral tolerance. A previous report had shown the development of... more
There have been numerous studies linking complement components and the pathogenesis of systemic lupus erythematosus (SLE). This is due to their numerous roles in modulating immune responses in the human body. This study examined the... more
BACKGROUND Recurrent pregnancy loss (RPL) is linked to lower vitamin D levels and altered immune responses, though unclear mechanisms. This study aimed to identify the effect of vitamin D on the balance between interleukin (IL)-10/IL-17A... more
Background: Semantic Web technology can considerably catalyze translational genetics and genomics research in medicine, where the interchange of information between basic research and clinical levels becomes crucial. This exchange... more
A third of African Americans with sporadic focal segmental glomerulosclerosis (FSGS) or HIV-associated nephropathy (HIVAN) do not carry APOL1 renal risk genotypes. This raises the possibility that other APOL1 variants may contribute to... more
BACKGROUND AND OBJECTIVE: Neonatal respiratory distress syndrome (RDS) due to pulmonary surfactant deficiency is heritable, but common variants do not fully explain disease heritability. METHODS: Using next-generation, pooled sequencing... more
Fasting glucose and insulin are intermediate traits for type 2 diabetes. Here we explore the role of coding variation on these traits by analysis of variants on the HumanExome BeadChip in 60,564 non-diabetic individuals and in 16,491 T2D... more
With the increasing concern for health and nutrition, dietary fat has attracted considerable attention. The composition of fatty acids in the diet is important because they are associated with major diseases including cancers, diabetes,... more
Background: Despite the important roles of vascular smooth muscle cells and endothelial cells in atherosclerotic lesion formation, data regarding the associations of functional polymorphisms in the genes encoding growth factors with the... more
Rationale: Acute respiratory distress syndrome (ARDS) behaves as a complex genetic trait, yet knowledge of genetic susceptibility factors remains incomplete. Objectives: To identify genetic risk variants for ARDS using large scale... more
The DNA Data Bank of Japan Center (DDBJ Center; ) maintains and provides public archival, retrieval and analytical services for biological information. Since October 2013, DDBJ Center has operated the Japanese Genotypephenotype Archive... more
The DNA Data Bank of Japan Center (DDBJ Center; http://www.ddbj.nig.ac.jp) maintains and provides public archival, retrieval and analytical services for biological information. Since October 2013, DDBJ Center has operated the Japanese... more
Hereditary recurrent fevers (HRF) are a group of rare monogenic diseases leading to recurrent inflammatory flares. A large number of variants has been described for the four genes associated with the best known HRF, namely MEFV, NLRP3,... more
The type I interferon system genes IKBKE and IFIH1 are associated with the risk of systemic lupus erythematosus (SLE). To identify the sequence variants that are able to account for the disease association, we resequenced the genes IKBKE... more
Objectives-To determine if alpha-synuclein REP1 genotypes are associated with survival in Parkinson's disease. Methods-Investigators from the Genetic Epidemiology of Parkinson's Disease Consortium provided REP1 genotypes and baseline and... more
Objective: The objective of the investigation was to study the possible coexistence of pituitary adenoma and pheo/PGL. Design: Thirty-nine cases of sporadic or familial pheo/PGL and pituitary adenomas were investigated. Known pheo/PGL... more
Several common germline variants identified through genome-wide association studies of breast cancer risk in the general population have recently been shown to be associated with breast cancer risk for BRCA1 and/or BRCA2 mutation... more
Hirschsprung disease (HSCR) genetics is a paradigm for the study and understanding of multigenic disorders. Association between Down syndrome and HSCR suggests that genetic factors that predispose to HSCR map to chromosome 21. To identify... more
Background Genetic studies require precise phenotype definitions, but electronic medical record (EMR) phenotype data are recorded inconsistently and in a variety of formats. Objective To present lessons learned about validation of... more
To investigate whether the solute carrier family 1, member 3 (SLC1A3) gene, which encodes the glutamate aspartate transporter, is associated with normal tension glaucoma (NTG) in Japanese patients. Two hundred and ninety-five Japanese... more
To identify genetic factors contributing to amyotrophic lateral sclerosis (ALS), we conducted whole-exome analyses of 1,022 index familial ALS (FALS) cases and 7,315 controls. In a new screening strategy, we performed gene-burden analyses... more
Congenital hyperinsulinism (CHI) is a heterogeneous disorder of insulin dysregulation, leading to hypoglycemia. This study describes the clinical characteristics, genetics, and management of CHI in Argentina. We retrospectively reviewed... more
Punctate palmoplantar keratoderma (PPKP1; Buschke-Fischer-Brauer) is a rare autosomal dominant inherited skin disease characterized by multiple hyperkeratotic papules involving the palms and soles. Mutations have been found at 2 loci, on... more
Abstract Text: Under the assumption that human obesity genes not only regulate fat deposition but also energy homeostasis, we expected effects of those genes on milk fat yield. Therefore, we performed an association study with EBVs for... more
X-linked adrenoleukodystrophy (X-ALD) is an inherited metabolic disease associated with mutations in the ABCD1 gene that encodes an ATP-binding cassette transporter protein, ALDP. The disease is characterized by increased concentrations... more
Background: Aggressiveness in humans is a hereditary behavioral trait that mobilizes all systems of the body-first of all, the nervous and endocrine systems, and then the respiratory, vascular, muscular, and others-e.g., for the defense... more
Idiopathic pulmonary fibrosis (IPF) is an age-related disease featuring progressive lung scarring. To elucidate the molecular basis of IPF, we performed exome sequencing of familial pulmonary Users may view, print, copy, and download text... more
We describe a metabolic disorder characterized by lipodystrophy, hepatic steatosis, insulin resistance, severe diabetes, and growth retardation observed in mice carrying N-ethyl-N-nitrosourea (ENU)-induced mutations. The disorder was... more
Background Bardet-Biedl syndrome (BBS) is a pleiotropic recessive disorder that belongs to the rapidly growing family of ciliopathies. It shares phenotypic traits with other ciliopathies, such as Alstro ¨m syndrome (ALMS),... more
Most Congenital Adrenal Hyperplasia (CAH) patients carry CYP21A2 mutations derived from conversion events involving the pseudogene, and the remaining carry new mutations. To review causal mutations and genotype-phenotype correlation in... more
Type 1 diabetes mellitus (T1DM) is a serious autoimmune condition that arises from the destruction of insulin-producing beta cells in the pancreas. It is a prevalent chronic disease among children if left untreated with lifelong insulin... more
We report a case of a 46-year-old woman with hypertension and autosomal dominant polycystic kidney disease who presented with chest pain and was found to have spontaneous coronary artery dissection (SCAD) on diagnostic catheterization. We... more
In genetic association studies, a single marker is often associated with multiple, correlated phenotypes (e.g., obesity and cardiovascular disease, or nicotine dependence and lung cancer). A pervasive question is then whether that marker... more
Salt sensitivity is estimated to be present in 51% of the hypertensive and 26% of the normotensive populations. The individual blood pressure response to salt is heterogeneous and possibly related to inherited susceptibility. Although the... more
The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population... more
Objective: Case-control studies have not been consistent in showing association between apolipoprotein E (APOE) polymorphisms and frontotemporal lobar degeneration (FTLD), producing contradictory findings. The study objective was to... more
To investigate the association of lysyl oxidase like 1 (LOXL1) variants with exfoliation syndrome (XFS), exfoliation glaucoma (XFG), and primary open angle glaucoma (POAG) in a Turkish population. Two LOXL1 single nucleotide polymorphisms... more
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