Genetic Risk and the Development of Autoimmune Liver Disease

2015 ◽  
Vol 33 (Suppl. 2) ◽  
pp. 13-24 ◽  
Author(s):  
Tom H. Karlsen ◽  
Brian K. Chung
Keyword(s):  
Genetic Risk ◽  
Liver Diseases ◽  
Disease Risk ◽  
Association Studies ◽  
Strong Association ◽  
Human Leukocyte ◽  
Biliary Cirrhosis ◽  
Genome Wide Association Studies ◽  
Autoimmune Liver Diseases ◽  
Study Designs

Primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) have collectively been recognized as autoimmune liver diseases. They have all been subjected to genome-wide association studies (GWAS) and several dozens susceptibility loci have been determined. The predominant feature of the genetic findings is that of a strong association with the human leukocyte antigen (HLA) and numerous weak associations scattered throughout the remainder of the genome. The non-HLA associations show some degree of overlap, not only between PBC, PSC and AIH, but also with other autoimmune and immune-mediated diseases. Mathematical modelling shows that the main fraction of autoimmune disease risk (including that of autoimmune liver diseases) is not explained by GWAS, proposing a major role of environmental factors. The HLA associations and autoantibodies observed in these conditions may hold clues as to the nature of such factors, which are exceedingly difficult to map by means of epidemiological study designs. The present review article explores the potential relationship between genetic risk as determined by GWAS and environmental risk in autoimmune liver diseases, and proposes a model for relevant thinking on the susceptibility genes in PBC, PSC and AIH.

Genetics of systemic sclerosis

2020 ◽  
Vol 5 (3) ◽  
pp. 192-201 ◽  
Author(s):  
Yuki Ishikawa ◽  
Chikashi Terao
Keyword(s):  
Systemic Sclerosis ◽  
Disease Risk ◽  
Association Studies ◽  
Human Leukocyte ◽  
Premature Death ◽  
Microvascular Dysfunction ◽  
Candidate Gene Approach ◽  
Genome Wide Association Studies ◽  
Genetic Associations ◽  
Genetic Components

Systemic sclerosis is an autoimmune disease characterized by generalized fibrosis in connective tissues and internal organs as consequences of microvascular dysfunction and immune dysfunctions, which leads to premature death in affected individuals. The etiology of systemic sclerosis is complex and poorly understood, but as with most autoimmune diseases, it is widely accepted that both environmental and genetic factors contribute to disease risk. During the last decade, the number of genetic markers convincingly associated with systemic sclerosis has exponentially increased. In this article, we briefly mention the genetic components of systemic sclerosis. Then, we review the classical and novel genetic associations with systemic sclerosis, analyzing the firmest and replicated signals within non–human leukocyte antigen genes, identified by both candidate gene approach and genome-wide association studies. We also provide an insight into the future perspectives that will shed more light into the complex genetic background of the disease. Despite the remarkable advance of systemic sclerosis genetics during the last decade, the use of the new genetic technologies such as next-generation sequencing, as well as the deep phenotyping of the study cohorts, to fully characterize the genetic component of this disease is imperative to identify causal variants, which leads to more targeted and effective treatment of systemic sclerosis.

scholarly journals Functional regulatory variants implicate distinct transcriptional networks in dementia

2021 ◽  
Author(s):  
Yonatan A. Cooper ◽  
Jessica E. Davis ◽  
Sriram Kosuri ◽  
Giovanni Coppola ◽  
Daniel H. Geschwind
Keyword(s):  
Genetic Risk ◽  
Disease Risk ◽  
Specific Activity ◽  
Association Studies ◽  
Transcriptional Networks ◽  
Genome Wide Association Studies ◽  
Regulatory Variants ◽  
Functional Variants ◽  
Common Genetic Variants ◽  
Complement 4

Predicting functionality of noncoding variation is one of the major challenges in modern genetics. We employed massively parallel reporter assays to screen 5,706 variants from genome-wide association studies for both Alzheimers disease (AD) and Progressive Supranuclear Palsy (PSP). We identified 320 functional regulatory polymorphisms (SigVars) comprising 27 of 34 unique tested loci, including multiple independent signals across the complex 17q21.31 region. We identify novel risk genes including PLEKHM1 in PSP and APOC1 in AD, and perform gene-editing to validate four distinct causal loci, confirming complement 4 (C4A) as a novel genetic risk factor for AD. Moreover, functional variants preferentially disrupt transcription factor binding sites that converge on enhancers with differential cell-type specific activity in PSP and AD, implicating a neuronal SP1-driven regulatory network in PSP pathogenesis. These analyses support a novel mechanism underlying noncoding genetic risk, whereby common genetic variants drive disease risk via their aggregate activity on specific transcriptional programs.

scholarly journals Genetic Epidemiology in Latin America: Identifying Strong Genetic Proxies for Complex Disease Risk Factors

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 507
Author(s):  
Carolina Bonilla ◽  
Lara Novaes Baccarini
Keyword(s):  
Latin America ◽  
Genetic Variants ◽  
Complex Disease ◽  
Disease Risk ◽  
Association Studies ◽  
Strong Association ◽  
Genome Wide Association Studies ◽  
Reverse Causation ◽  
Health And Wellbeing ◽  
Genome Wide

Epidemiology seeks to determine the causal effects of exposures on outcomes related to the health and wellbeing of populations. Observational studies, one of the most commonly used designs in epidemiology, can be biased due to confounding and reverse causation, which makes it difficult to establish causal relationships. In recent times, genetically informed methods, like Mendelian randomization (MR), have been developed in an attempt to overcome these disadvantages. MR relies on the association of genetic variants with outcomes of interest, where the genetic variants are proxies or instruments for modifiable exposures. Because genotypes are sorted independently and at random at the time of conception, they are less prone to confounding and reverse causation. Implementation of MR depends on, among other things, a strong association of the genetic variants with the exposure, which has usually been defined via genome-wide association studies (GWAS). Because GWAS have been most often carried out in European populations, the limited identification of strong instruments in other populations poses a major problem for the application of MR in Latin America. We suggest potential solutions that can be realized with the resources at hand and others that will have to wait for increased funding and access to technology.

scholarly journals Genetic Contribution to the Pathogenesis of Primary Biliary Cholangitis

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Satoru Joshita ◽  
Takeji Umemura ◽  
Eiji Tanaka ◽  
Masao Ota
Keyword(s):  
Association Studies ◽  
Disease Onset ◽  
Human Leukocyte ◽  
Primary Biliary Cholangitis ◽  
Cholestatic Liver Disease ◽  
Biliary Cirrhosis ◽  
Genome Wide Association Studies ◽  
Antimitochondrial Antibodies ◽  
Leukocyte Antigen ◽  
Genome Wide

Formerly termed primary biliary cirrhosis, primary biliary cholangitis (PBC) is a chronic and progressive cholestatic liver disease characterized by the presence of antimitochondrial antibodies. Ursodeoxycholic acid (UDCA) therapy is the most effective and approved treatment for PBC and leads to a favorable outcome in the vast majority of cases. Although the etiology of PBC has not yet been elucidated, human leukocyte antigen (HLA) class II alleles have been consistently associated with disease onset for decades. Individuals in different geographic regions of the world may have varying susceptibility alleles that reflect indigenous triggering antigens. In this review, we describe the influence of HLA alleles and other gene polymorphisms on PBC along with the results of genome-wide association studies (GWAS) on this disease.

scholarly journals Distribution of 54 polygenic risk scores for common diseases in long lived individuals and their offspring

2021 ◽  
Author(s):  
Sophia Gunn ◽  
Michael Wainberg ◽  
Zeyuan Song ◽  
Stacy Andersen ◽  
Robert Boudreau ◽  
...  
Keyword(s):  
General Population ◽  
Genetic Risk ◽  
Disease Risk ◽  
Association Studies ◽  
Risk Scores ◽  
Human Longevity ◽  
Genome Wide Association Studies ◽  
Predictive Values ◽  
Polygenic Risk ◽  
Polygenic Scores

Background: A surprising and well-replicated result in genetic studies of human longevity is that centenarians appear to carry disease-associated variants in numbers similar to the general population. With the proliferation of large genome-wide association studies (GWAS) in recent years, investigators have turned to polygenic scores to leverage GWAS results into a measure of genetic risk that can better predict risk of disease than individual significant variants alone. Methods: We selected 54 polygenic risk scores (PRSs) developed for a variety of outcomes and we calculated their values in individuals from the New England Centenarian Study (NECS, N = 4886) and the Long Life Family Study (LLFS, N = 4577). We compared the distribution of these PRSs among exceptionally long-lived individuals (ELLI), their offspring and controls and we also examined their predictive values, using t-tests and regression models adjusting for sex and principal components reflecting ancestral background of the individuals (PCs). In our analyses we controlled for multiple testing using a Bonferroni-adjusted threshold for 54 traits. Results: We found that only 4 of the 54 PRSs differed between ELLIs and controls in both cohorts. ELLIs had significantly lower mean PRSs for Alzheimer's disease (AD), coronary artery disease (CAD) and systemic lupus than controls, suggesting genetic predisposition to extreme longevity may be mediated by reduced susceptibility to these traits. ELLIs also had significantly higher mean PRSs for improved cognitive function. In addition, the PRS for AD was associated with higher risk of dementia among controls but not ELLIs (p = 0.0004, 0.3 in NECS, p = 0.03, 0.93 in LLFS respectively). Interestingly, ELLIs did not have a larger number of homozygous risk genotypes for AD (TNECS = -1.72, TLLFs = 0.83) and CAD (TNECS = -5.08, TLLFs = -0.31) in both cohorts, but did have significantly larger number of homozygous protective genotypes than controls for the two traits (AD: TNECS =3.10, TLLFs = 2.2, CAD: TNECS = 6.57, TLLFs =2.36, respectively). Conclusions: ELLIs have a similar burden of genetic disease risk as the general population for most traits, but have significantly lower genetic risk of AD, CAD, and lupus. The lack of association between AD PRS and dementia among ELLIs suggests that their genetic risk for AD is somehow buffered by protective genetic or environmental factors.

Genome-wide association studies and genetic risk assessment of liver diseases

2010 ◽  
Vol 7 (12) ◽  
pp. 669-681 ◽  
Author(s):  
Marcin Krawczyk ◽  
Roman Müllenbach ◽  
Susanne N. Weber ◽  
Vincent Zimmer ◽  
Frank Lammert
Keyword(s):  
Risk Assessment ◽  
Genetic Risk ◽  
Liver Diseases ◽  
Association Studies ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Genetic Risk Assessment ◽  
Genome Wide

Strong Association between Serotonin Transporter 5-HTTVNTR Variant and Psychoactive Substance (Nicotine) Use in the Turkish Cypriot Population

2020 ◽  
Vol 21 (6) ◽  
pp. 466-470
Author(s):  
Emine Kandemis ◽  
Gulten Tuncel ◽  
Ozen Asut ◽  
Sehime G. Temel ◽  
Mahmut C. Ergoren
Keyword(s):  
Serotonin Transporter ◽  
Association Studies ◽  
Strong Association ◽  
Smoking Behavior ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Genotype Distribution ◽  
Psychological Traits ◽  
Wide Range ◽  
Turkish Cypriot

Background: The use of psychoactive substances is one of the most dangerous social problems worldwide. Nicotine dependence results from the interaction between neurobiological, environmental and genetic factors. Serotonin is a neurotransmitter that has a wide range of central nervous system activities. The serotonin transporter gene has been previously linked to psychological traits. Objective: A variable number of tandem repeats within the serotonin transporter-linked polymorphic gene region are believed to alter the transcriptional efficiency of the 5-HTT gene. Therefore, we aimed to investigate the association between this polymorphic site and smoking behavior in the Turkish Cypriot population. Methods: A total of 259 (100 smokers, 100 non-smokers and 59 ex-smokers) Turkish Cypriots were included in this population-based cross-sectional study. Genomic DNA was extracted from peripheral blood samples and the 5-HTTVNTR2 polymorphisms were determined by the PCR-RFLP. Results: The allelic frequency and genotype distribution results of this study showed a strong association (P<0.0001) between smokers and non-smokers. No statistical significance was found between non-smokers and ex-smokers. Conclusion: This is the first genetic epidemiology study to investigate the allelic frequencies of 5-HTTVNTR2 polymorphisms associated with smoking behavior in the Turkish Cypriot population. Based on the results of this study, genome-wide association studies should be designed for preventive medicine in this population.

scholarly journals Case–Parent Trio Studies in Cleft Lip and Palate

2020 ◽  
Vol 07 (03) ◽  
pp. 075-079
Author(s):  
Mahamad Irfanulla Khan ◽  
Prashanth CS
Keyword(s):  
Genetic Variants ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Association Studies ◽  
Geographical Location ◽  
Genetic Association Studies ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Family Based ◽  
Study Designs

AbstractCleft lip with or without cleft palate (CL/P) is one of the most common congenital malformations in humans involving various genetic and environmental risk factors. The prevalence of CL/P varies according to geographical location, ethnicity, race, gender, and socioeconomic status, affecting approximately 1 in 800 live births worldwide. Genetic studies aim to understand the mechanisms contributory to a phenotype by measuring the association between genetic variants and also between genetic variants and phenotype population. Genome-wide association studies are standard tools used to discover genetic loci related to a trait of interest. Genetic association studies are generally divided into two main design types: population-based studies and family-based studies. The epidemiological population-based studies comprise unrelated individuals that directly compare the frequency of genetic variants between (usually independent) cases and controls. The alternative to population-based studies (case–control designs) includes various family-based study designs that comprise related individuals. An example of such a study is a case–parent trio design study, which is commonly employed in genetics to identify the variants underlying complex human disease where transmission of alleles from parents to offspring is studied. This article describes the fundamentals of case–parent trio study, trio design and its significances, statistical methods, and limitations of the trio studies.

scholarly journals Association analysis of juvenile idiopathic arthritis genetic susceptibility factors in Estonian patients

2021 ◽  
Author(s):  
Tiit Nikopensius ◽  
Priit Niibo ◽  
Toomas Haller ◽  
Triin Jagomägi ◽  
Ülle Voog-Oras ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Juvenile Idiopathic Arthritis ◽  
Autoimmune Diseases ◽  
Genetic Risk ◽  
Association Studies ◽  
Control Sample ◽  
Case Control ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Genome Wide

Abstract Background Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition of childhood. Genetic association studies have revealed several JIA susceptibility loci with the strongest effect size observed in the human leukocyte antigen (HLA) region. Genome-wide association studies have augmented the number of JIA-associated loci, particularly for non-HLA genes. The aim of this study was to identify new associations at non-HLA loci predisposing to the risk of JIA development in Estonian patients. Methods We performed genome-wide association analyses in an entire JIA case–control sample (All-JIA) and in a case–control sample for oligoarticular JIA, the most prevalent JIA subtype. The entire cohort was genotyped using the Illumina HumanOmniExpress BeadChip arrays. After imputation, 16,583,468 variants were analyzed in 263 cases and 6956 controls. Results We demonstrated nominal evidence of association for 12 novel non-HLA loci not previously implicated in JIA predisposition. We replicated known JIA associations in CLEC16A and VCTN1 regions in the oligoarticular JIA sample. The strongest associations in the All-JIA analysis were identified at PRKG1 (P = 2,54 × 10−6), LTBP1 (P = 9,45 × 10−6), and ELMO1 (P = 1,05 × 10−5). In the oligoarticular JIA analysis, the strongest associations were identified at NFIA (P = 5,05 × 10−6), LTBP1 (P = 9,95 × 10−6), MX1 (P = 1,65 × 10−5), and CD200R1 (P = 2,59 × 10−5). Conclusion This study increases the number of known JIA risk loci and provides additional evidence for the existence of overlapping genetic risk loci between JIA and other autoimmune diseases, particularly rheumatoid arthritis. The reported loci are involved in molecular pathways of immunological relevance and likely represent genomic regions that confer susceptibility to JIA in Estonian patients. Key Points• Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease with heterogeneous presentation and genetic predisposition.• Present genome-wide association study for Estonian JIA patients is first of its kind in Northern and Northeastern Europe.• The results of the present study increase the knowledge about JIA risk loci replicating some previously described associations, so adding weight to their relevance and describing novel loci.• The study provides additional evidence for the existence of overlapping genetic risk loci between JIA and other autoimmune diseases, particularly rheumatoid arthritis.

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