scholarly journals Tackling Missing Heritability by Use of an Optimum Curve: A Systematic Review and Meta-Analysis

2019 ◽  
Vol 20 (20) ◽  
pp. 5104 ◽  
Author(s):  
Anneke Wegener Sleeswijk ◽  
Reinout Heijungs ◽  
Sarah Durston
Keyword(s):  
Systematic Review ◽  
Association Studies ◽  
Meta Analysis ◽  
Genetic Association Studies ◽  
Proof Of Concept ◽  
Missing Heritability ◽  
Complex Disorders ◽  
Preferential Transmission ◽  
Biological Variable ◽  
Genes And Environment

Missing heritability is a common problem in psychiatry that impedes precision medicine approaches to autism and other heritable complex disorders. This proof-of-concept study uses a systematic review and meta-analysis of the association between variants of the serotonin transporter promoter (5-HTTLPR) and autism to explore the hypothesis that some missing heritability can be explained using an optimum curve. A systematic literature search was performed to identify transmission disequilibrium tests on the short/long (S/L) 5-HTTLPR polymorphism in relation to autism. We analysed five American, seven European, four Asian and two American/European samples. We found no transmission preference in the joint samples and in Europe, preferential transmission of S in America and preferential transmission of L in Asia. Heritability will be underestimated or missed in genetic association studies if two alternative genetic variants are associated with the same disorder in different subsets of a sample. An optimum curve, relating a multifactorial biological variable that incorporates genes and environment to a score for a human trait, such as social competence, can explain this. We suggest that variants of functionally related genes will sometimes appear in fixed combinations at both sides of an optimum curve and propose that future association studies should account for such combinations.

scholarly journals Genetic Association Studies of Red Blood Cell Transfusion Related Alloimmunization: A Systematic Review and Meta-Analysis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2459-2459
Author(s):  
Jorn Gerritsma ◽  
Ilja Oomen ◽  
Sanne Meinderts ◽  
C. Ellen van der Schoot ◽  
Bart J. Biemond ◽  
...  
Keyword(s):  
Systematic Review ◽  
Genetic Variants ◽  
Screening Tool ◽  
Association Studies ◽  
Data Extraction ◽  
Meta Analysis ◽  
Genetic Association Studies ◽  
Risk Of Bias ◽  
Cell Disease

Introduction: Blood transfusions are an important treatment modality for patients with either acute or chronic onset anemia such as trauma, sickle cell disease, and hematological malignancies. Transfusion poses a risk for alloimmunization, which may lead to potentially lethal transfusion reactions. A promising strategy to prevent alloimmunization is extensive matching on blood groups, yet this is a costly procedure and should be reserved for patients at highest risk for alloimmunization. Identification of genetic variants that increase the risk for alloimmunization might help to identify high-risk patients and could be used as a screening tool for patients receiving multiple transfusions. Objectives: To summarize all available evidence on genetic risk factors for alloimmunization after blood transfusion. Design: Systematic review with meta-analysis of observational studies. Studies were only included in the meta-analysis if polymorphisms were tested at least 3 times, and if ethnic background of the population and the control populations were comparable between studies. Data sources: The online databases Embase, MEDLINE and the Cochrane Library were search for relevant articles with search terms: 1) transfusion, 2) alloimmunization 3) genetics. The search was last updated March 2018. Eligibility criteria: 1) Primary study that assessed the association of genetic polymorphisms with transfusion related alloimmunization, 2) a human population, 3) studies with at least 50 patients, 4) full text availability. Data extraction: Two reviewers independently screened articles for eligibility, extracted data using a standardized data extraction form. Extracted data included study setting, study population, participant demographics, baseline characteristics, study methodology, comparisons and outcome, and risk of bias. Primary outcome measure: Alloimmunization after one or more blood transfusions. Risk of bias assessment: The quality of the included studies was assessed by the Q-genie tool for genetic association studies. Results: A total of 2045 cases and 24084 controls were derived from 18 genetic case-control studies that were included in this systematic review. Most commonly studied disease group was sickle cell disease (SCD) (8 studies). Three studies included patients with different diseases and seven studies did not report the underlying disease. Eleven studies identified the association of HLA polymorphisms with alloimmunization and 8 studies focused on non-HLA variants. Overall quality of the included studies was moderate (11 studies), 2 studies were of high quality, and 5 studies were ranked as poor. HLA-DRB1*04 (Odds Ratio 7.16, 95%CI 3.87-13.22, P<0.00001) and HLA-DRB1*15 (OR 3.01, 95%CI 1.84-5.53, P<0.0001) were by meta-analysis significantly associated with anti-Fy(a) formation, although there was considerable heterogeneity (I2=78% and 55% respectively). Moreover, HLA-DRB1*10 (OR 2.64, 95%CI 1.41-4.95, P=0.002), HLA*DRB1*11 (OR 2.11, 95%CI 1.34-3.32, P=0.001), and HLA-DRB1*13 (OR 1.71, 95%CI 1.26-2.33, P=0.0006) were overall associated with anti-Kell formation. Heterogeneity was less prominent with an I2 of 0%, 54% and 19% respectively (Figure 1). No other variants were eligible for meta-analysis. Non-HLA variants were tested less extensively, as most variants were reported by only 1 study. Polymorphisms of genes in the immunomodulatory pathways were assessed most frequently. Of these variants, FC-gamma-receptor 2C.nc-ORF was associated with a decreased risk of alloimmunization in SCD (OR 0.26, 95%CI 0.11-0.64, p=0.003). All other associations that were described as significant by the original articles were summarized in Figure 2. Discussion: There is limited evidence supporting the role of genetic risk factors for alloimmunization. The results of our meta-analysis suggest that several HLA polymorphisms potentially influence antigen presentation of the Duffy(a) and Kell antigen. Once confirmed by experimental studies, these polymorphisms could be used as a screening tool for the prevention of alloimmunization among frequently transfused patients. Overall, the effect of genetic variants on alloimmunization has mostly been assessed by small studies, hampering reliable interpretation of the results. Future studies should include large and well-defined cohorts when performing genetic analysis on this complicated subject. Disclosures No relevant conflicts of interest to declare.

scholarly journals A systematic review and meta-analysis of genetic association studies for the role of inflammation and the immune system in diabetic nephropathy

2017 ◽  
Vol 10 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Maria Tziastoudi ◽  
Ioannis Stefanidis ◽  
Georgios M. Hadjigeorgiou ◽  
Konstantinos Stravodimos ◽  
Elias Zintzaras
Keyword(s):  
Systematic Review ◽  
Diabetic Nephropathy ◽  
Immune System ◽  
Genetic Association ◽  
Association Studies ◽  
Meta Analysis ◽  
Genetic Association Studies

scholarly journals A systematic review and meta-analysis of host genetic factors associated with influenza severity

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Nina Van Goethem ◽  
Célestin Danwang ◽  
Nathalie Bossuyt ◽  
Herman Van Oyen ◽  
Nancy H. C. Roosens ◽  
...  
Keyword(s):  
Systematic Review ◽  
Genetic Factors ◽  
Association Studies ◽  
Influenza Infection ◽  
Meta Analysis ◽  
Genetic Association Studies ◽  
Genome Wide Association Studies ◽  
Severe Influenza ◽  
Host Genetic ◽  
Host Genetic Factors

Abstract Background The severity of influenza disease can range from mild symptoms to severe respiratory failure and can partly be explained by host genetic factors that predisposes the host to severe influenza. Here, we aimed to summarize the current state of evidence that host genetic variants play a role in the susceptibility to severe influenza infection by conducting a systematic review and performing a meta-analysis for all markers with at least three or more data entries. Results A total of 34 primary human genetic association studies were identified that investigated a total of 20 different genes. The only significant pooled ORs were retrieved for the rs12252 polymorphism: an overall OR of 1.52 (95% CI [1.06–2.17]) for the rs12252-C allele compared to the rs12252-T allele. A stratified analysis by ethnicity revealed opposite effects in different populations. Conclusion With exception for the rs12252 polymorphism, we could not identify specific genetic polymorphisms to be associated with severe influenza infection in a pooled meta-analysis. This advocates for the use of large, hypothesis-free, genome-wide association studies that account for the polygenic nature and the interactions with other host, pathogen and environmental factors.

scholarly journals Systematic review and meta-analysis of genetic association studies of pelvic organ prolapse

2021 ◽  
Author(s):  
Kristina Allen-Brady ◽  
John W. F. Chua ◽  
Romana Cuffolo ◽  
Marianne Koch ◽  
Felice Sorrentino ◽  
...  
Keyword(s):  
Systematic Review ◽  
Pelvic Organ Prolapse ◽  
Association Studies ◽  
Data Extraction ◽  
Meta Analysis ◽  
Twin Studies ◽  
Genetic Association Studies ◽  
Pelvic Organ ◽  
Genome Wide Association Studies ◽  
Meta Analyses

Abstract Introduction and hypothesis Family and twin studies demonstrate that pelvic organ prolapse (POP) is heritable, but the genetic etiology is poorly understood. This review aimed to identify genetic loci and specific polymorphisms associated with POP, while assessing the strength, consistency, and risk of bias among reported associations. Methods Updating an earlier systematic review, PubMed and HuGE Navigator as well as relevant conference abstracts were searched using genetic and phenotype keywords from 2015 to 2020. Screening and data extraction were performed in duplicate. Fixed and random effects meta-analyses were conducted using co-dominant models of inheritance. We assessed credibility of pooled associations using interim Venice criteria. Results We screened 504 new abstracts and included 46 published and 7 unpublished studies. In pooled analyses we found significant associations for four polymorphisms: rs2228480 at the ESR1 gene (OR 0.67 95% CI 0.46–0.98, I2 = 0.0%, Venice rating BAB), rs12589592 at the FBLN5 gene (OR 1.46 95% CI 1.11–1.82, I2 = 36.3%, Venice rating BBB), rs484389 in the PGR gene (OR 0.61 95% CI 0.39–0.96, I2 = 32.4%, Venice rating CBB), and rs1800012 at the COL1A1 gene (OR 0.80 95% CI 0.66–0.96, I2 = 0.0%, Venice rating BAB). Further credible novel variants have also been recently identified in genome-wide association studies. Conclusion The genetic contributions to POP remain poorly understood. Several biologically plausible variants have been identified, but much work is required to establish the role of these genes in the pathogenesis of POP or to establish a role for genetic testing in clinical practice.

scholarly journals The genetic map of diabetic nephropathy: evidence from a systematic review and meta-analysis of genetic association studies

2020 ◽  
Vol 13 (5) ◽  
pp. 768-781
Author(s):  
Maria Tziastoudi ◽  
Ioannis Stefanidis ◽  
Elias Zintzaras
Keyword(s):  
Systematic Review ◽  
Diabetic Nephropathy ◽  
Genetic Association ◽  
Pathway Analysis ◽  
Methylenetetrahydrofolate Reductase ◽  
Association Studies ◽  
Meta Analysis ◽  
Genetic Association Studies ◽  
Sirtuin 1 ◽  
Genotype Distribution

Abstract Despite the extensive efforts of scientists, the genetic background of diabetic nephropathy (DN) has not yet been clarified. To elucidate the genetic variants that predispose to the development of DN, we conducted a systematic review and meta-analysis of all available genetic association studies (GAS) of DN. We searched in the Human Genome Epidemiology Navigator (HuGE Navigator) and PubMed for available GAS of DN. The threshold for meta-analysis was three studies per genetic variant. The association between genotype distribution and DN was examined using the generalized linear odds ratio (ORG). For variants with available allele frequencies, the examined model was the allele contrast. The pooled OR was estimated using the DerSimonian and Laird random effects model. The publication bias was assessed with Egger’s test. We performed pathway analysis of significant genes with DAVID 6.7. Genetic data of 606 variants located in 228 genes were retrieved from 360 GASs and were synthesized with meta-analytic methods. ACACB, angiotensin I-converting enzyme (ACE), ADIPOQ, AGT, AGTR1, AKR1B1, APOC1, APOE, ATP1B2, ATP2A3, CARS, CCR5, CGNL1, Carnosine dipeptidase 1 (CNDP1), CYGB-PRCD, EDN1, Engulfment and cell motility 1 (ELMO1), ENPP1, EPO, FLT4, FTO, GLO1, HMGA2, IGF2/INS/TH cluster, interleukin 1B (IL1B), IL8, IL10, KCNQ1, KNG, LOC101927627, Methylenetetrahydrofolate reductase, nitric oxide synthase 3 (NOS3), SET domain containing seven, histone lysine methyltransferase (SETD7), Sirtuin 1 (SIRT1), SLC2A1, SLC2A2, SLC12A3, SLC19A3, TCF7L2, TGFB1, TIMP1, TTC39C, UNC13B, VEGFA, WTAPP1, WWC1 as well as XYLT1 and three intergenic polymorphisms showed significant association with DN. Pathway analysis revealed the overrepresentation of six signalling pathways. The significant findings provide further evidence for genetic factors implication in DN offering new perspectives in discovery of new therapies.

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