scholarly journals The Genetic Architecture of a Congenital Heart Defect Is Related to Its Fitness Cost

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1368
Author(s):  
Ehiole Akhirome ◽  
Suk D. Regmi ◽  
Rachel A. Magnan ◽  
Nelson Ugwu ◽  
Yidan Qin ◽  
...  
Keyword(s):  
Genetic Architecture ◽  
Congenital Heart ◽  
Cardiac Development ◽  
Heart Defects ◽  
Inbred Strains ◽  
Fitness Cost ◽  
Atrioventricular Septal Defects ◽  
Septal Defects ◽  
Heart Defect ◽  
Phenotypic Robustness

In newborns, severe congenital heart defects are rarer than mild ones. This epidemiological relationship between heart defect severity and incidence lacks explanation. Here, an analysis of ~10,000 Nkx2-5+/− mice from two inbred strain crosses illustrates the fundamental role of epistasis. Modifier genes raise or lower the risk of specific defects via pairwise (G×GNkx) and higher-order (G×G×GNkx) interactions with Nkx2-5. Their effect sizes correlate with the severity of a defect. The risk loci for mild, atrial septal defects exert predominantly small G×GNkx effects, while the loci for severe, atrioventricular septal defects exert large G×GNkx and G×G×GNkx effects. The loci for moderately severe ventricular septal defects have intermediate effects. Interestingly, G×G×GNkx effects are three times more likely to suppress risk when the genotypes at the first two loci are from the same rather than different parental inbred strains. This suggests the genetic coadaptation of interacting G×G×GNkx loci, a phenomenon that Dobzhansky first described in Drosophila. Thus, epistasis plays dual roles in the pathogenesis of congenital heart disease and the robustness of cardiac development. The empirical results suggest a relationship between the fitness cost and genetic architecture of a disease phenotype and a means for phenotypic robustness to have evolved.

scholarly journals The fitness cost of a congenital heart defect shapes its genetic architecture

2019 ◽  
Author(s):  
Ehiole Akhirome ◽  
Suk D. Regmi ◽  
Rachel A. Magnan ◽  
Nelson Ugwu ◽  
Yidan Qin ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Congenital Heart Defect ◽  
Genetic Architecture ◽  
Congenital Heart ◽  
Septal Defect ◽  
Heart Defects ◽  
Atrioventricular Septal Defect ◽  
Fitness Cost ◽  
Heart Defect

ABSTRACTBackgroundIn newborns, severe congenital heart defects are rarer than mild ones. The reason why is unknown, but presumably related to a liability threshold that rises with the severity of a defect. Because the same genetic mutation can cause different defects, other variables may contribute to pushing an individual past a defect-specific liability threshold. We consider here how variables in the genetic architecture of a heart defect depend upon its fitness cost, as defined by the likelihood of survival to reproductive age in natural history studies.MethodsWe phenotyped ~10,000 Nkx2-5+/- newborn mice, a model of human congenital heart disease, from two inbred strain crosses. Genome-wide association analyses detected loci that modify the risk of an atrial septal defect, membranous or muscular ventricular septal defect, or atrioventricular septal defect. The number of loci, heritability and quantitative effects on risk of pairwise (G×GNkx) and higher-order (G×G×GNkx) epistasis between the loci and Nkx2-5 mutation were examined as a function of the fitness cost of a defect.ResultsNkx2-5+/- mice have pleiotropic heart defects; about 70% have normal hearts. The model recapitulates the epidemiological relationship between the severity and incidence of a heart defect. Neither the number of modifier loci nor heritability depends upon the severity of a defect, but G×GNkx and G×G×GNkx effects on risk do. Interestingly, G×G×GNkx effects are three times more likely to suppress risk when the genotypes at the first two loci are homozygous and from the same, rather than opposite strains in a cross. Syn- and anti-homozygous genotypes at G×G×GNkx interactions can have an especially large impact on the risk of an atrioventricular septal defect.ConclusionsGiven a modestly penetrant mutation, epistasis contributes more to the risk of severe than mild congenital heart defect. Conversely, genetic compatibility between interacting genes, as indicated by the protective effects of syn-homozygosity at G×G×GNkx interactions, plays a newfound role in the robustness of cardiac development. The experimental model offers practical insights into the nature of genetic risk in congenital heart disease. The results more fundamentally address a longstanding question regarding how mutational robustness could arise from natural selection.

scholarly journals Outflow Tract Formation—Embryonic Origins of Conotruncal Congenital Heart Disease

2021 ◽  
Vol 8 (4) ◽  
pp. 42
Author(s):  
Sonia Stefanovic ◽  
Heather C. Etchevers ◽  
Stéphane Zaffran
Keyword(s):  
Congenital Heart ◽  
Cardiac Development ◽  
Heart Defects ◽  
Dynamic Structure ◽  
Cell Types ◽  
Outflow Tract ◽  
Heart Tube ◽  
Heart Field ◽  
Multiple Cell ◽  
The Many

Anomalies in the cardiac outflow tract (OFT) are among the most frequent congenital heart defects (CHDs). During embryogenesis, the cardiac OFT is a dynamic structure at the arterial pole of the heart. Heart tube elongation occurs by addition of cells from pharyngeal, splanchnic mesoderm to both ends. These progenitor cells, termed the second heart field (SHF), were first identified twenty years ago as essential to the growth of the forming heart tube and major contributors to the OFT. Perturbation of SHF development results in common forms of CHDs, including anomalies of the great arteries. OFT development also depends on paracrine interactions between multiple cell types, including myocardial, endocardial and neural crest lineages. In this publication, dedicated to Professor Andriana Gittenberger-De Groot and her contributions to the field of cardiac development and CHDs, we review some of her pioneering studies of OFT development with particular interest in the diverse origins of the many cell types that contribute to the OFT. We also discuss the clinical implications of selected key findings for our understanding of the etiology of CHDs and particularly OFT malformations.

scholarly journals Abnormal Cardiac Development in the Absence of Heart Glycogen

2004 ◽  
Vol 24 (16) ◽  
pp. 7179-7187 ◽  
Author(s):  
Bartholomew A. Pederson ◽  
Hanying Chen ◽  
Jill M. Schroeder ◽  
Weinian Shou ◽  
Anna A. DePaoli-Roach ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Cardiac Muscle ◽  
Heart Development ◽  
Congenital Heart ◽  
Cardiac Development ◽  
Glycogen Synthase ◽  
Heart Defects ◽  
Mendelian Inheritance ◽  
And Function ◽  
Impaired Cardiac Function

ABSTRACT Glycogen serves as a repository of glucose in many mammalian tissues. Mice lacking this glucose reserve in muscle, heart, and several other tissues were generated by disruption of the GYS1 gene, which encodes an isoform of glycogen synthase. Crossing mice heterozygous for the GYS1 disruption resulted in a significant underrepresentation of GYS1-null mice in the offspring. Timed matings established that Mendelian inheritance was followed for up to 18.5 days postcoitum (dpc) and that ∼90% of GYS1-null animals died soon after birth due to impaired cardiac function. Defects in cardiac development began between 11.5 and 14.5 dpc. At 18.5 dpc, the hearts were significantly smaller, with reduced ventricular chamber size and enlarged atria. Consistent with impaired cardiac function, edema, pooling of blood, and hemorrhagic liver were seen. Glycogen synthase and glycogen were undetectable in cardiac muscle and skeletal muscle from the surviving null mice, and the hearts showed normal morphology and function. Congenital heart disease is one of the most common birth defects in humans, at up to 1 in 50 live births. The results provide the first direct evidence that the ability to synthesize glycogen in cardiac muscle is critical for normal heart development and hence that its impairment could be a significant contributor to congenital heart defects.

scholarly journals Focused Strategies for Defining the Genetic Architecture of Congenital Heart Defects

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 827
Author(s):  
Lisa J. Martin ◽  
D Woodrow Benson
Keyword(s):  
Genetic Variation ◽  
Congenital Heart Defects ◽  
Heart Development ◽  
Genetic Architecture ◽  
Congenital Heart ◽  
Rare Variants ◽  
Heart Defects ◽  
Genetic Origin ◽  
Genetic Studies ◽  
The Ideal

Congenital heart defects (CHD) are malformations present at birth that occur during heart development. Increasing evidence supports a genetic origin of CHD, but in the process important challenges have been identified. This review begins with information about CHD and the importance of detailed phenotyping of study subjects. To facilitate appropriate genetic study design, we review DNA structure, genetic variation in the human genome and tools to identify the genetic variation of interest. Analytic approaches powered for both common and rare variants are assessed. While the ideal outcome of genetic studies is to identify variants that have a causal role, a more realistic goal for genetic analytics is to identify variants in specific genes that influence the occurrence of a phenotype and which provide keys to open biologic doors that inform how the genetic variants modulate heart development. It has never been truer that good genetic studies start with good planning. Continued progress in unraveling the genetic underpinnings of CHD will require multidisciplinary collaboration between geneticists, quantitative scientists, clinicians, and developmental biologists.

scholarly journals Drosophila Heart as a Model for Cardiac Development and Diseases

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3078
Author(s):  
Anissa Souidi ◽  
Krzysztof Jagla
Keyword(s):  
Cardiac Dysfunction ◽  
Congenital Heart ◽  
Cardiac Development ◽  
Heart Diseases ◽  
Heart Defects ◽  
Fruit Fly ◽  
Model System ◽  
Fast Imaging

The Drosophila heart, also referred to as the dorsal vessel, pumps the insect blood, the hemolymph. The bilateral heart primordia develop from the most dorsally located mesodermal cells, migrate coordinately, and fuse to form the cardiac tube. Though much simpler, the fruit fly heart displays several developmental and functional similarities to the vertebrate heart and, as we discuss here, represents an attractive model system for dissecting mechanisms of cardiac aging and heart failure and identifying genes causing congenital heart diseases. Fast imaging technologies allow for the characterization of heartbeat parameters in the adult fly and there is growing evidence that cardiac dysfunction in human diseases could be reproduced and analyzed in Drosophila, as discussed here for heart defects associated with the myotonic dystrophy type 1. Overall, the power of genetics and unsuspected conservation of genes and pathways puts Drosophila at the heart of fundamental and applied cardiac research.

scholarly journals Oral corticosteroids during pregnancy and offspring risk of congenital heart defects: a nationwide cohort study

2019 ◽  
Vol 49 (2) ◽  
pp. 638-647
Author(s):  
Amalie Bøggild Schmidt ◽  
Marie Lund ◽  
Giulia Corn ◽  
Nina Øyen ◽  
Jan Wohlfahrt ◽  
...  
Keyword(s):  
Propensity Score ◽  
Confidence Interval ◽  
Congenital Heart Defects ◽  
Congenital Heart ◽  
Oral Corticosteroid ◽  
Heart Defects ◽  
Prevalence Ratio ◽  
Heart Defect ◽  
Causal Pathway ◽  
Oral Corticosteroids

Abstract Background Pre-pregnancy diabetes is a strong risk factor for congenital heart defects (CHDs), suggesting a role for glucose in the causal pathway. Oral corticosteroids may cause hyperglycemia and maternal use could affect embryonic heart development. The objective of this study was to determine the association between maternal intake of oral corticosteroids 0–8 weeks after conception and CHDs in offspring. Methods A register-based nationwide prevalence study including all live singleton births in Denmark, 1996–2016, was conducted. In total, 1 194 687 individuals and their mothers were identified and linked with information on offspring CHDs and the mothers’ use of oral corticosteroids in early pregnancy. Corticosteroid use was defined as a filled prescription for maternal use of oral corticosteroid 0–8 weeks after conception. CHDs were identified through International Classification of Diseases codes. The association was estimated by prevalence (odds) ratios using logistic regression and propensity score-matched analyses. Results Among 1 194 687 live births, 2032 had a mother who had used oral corticosteroids 0–8 weeks from conception. Of these offspring, 32 had a heart defect. Among the offspring of never-users of oral corticosteroids, 10 534 had a heart defect. The adjusted prevalence ratio was 1.29 (95% confidence interval, 0.90–1.84) comparing offspring prevalence of heart defects in oral corticosteroid users with that in oral corticosteroid never-users. Propensity score-matched analysis yielded similar results (prevalence ratio 1.38; 95% confidence interval, 0.95–2.02). Conclusions This study supports that there is no association between maternal use of oral corticosteroids in the first 8 weeks after conception and CHDs.

scholarly journals Maternal Hypertension-Related Genotypes and Congenital Heart Defects

2020 ◽  
Author(s):  
Yunping Lei ◽  
Katherine L Ludorf ◽  
Xiao Yu ◽  
Renata H Benjamin ◽  
Xue Gu ◽  
...  
Keyword(s):  
Congenital Heart Defects ◽  
Congenital Heart Defect ◽  
Genetic Risk ◽  
Congenital Heart ◽  
Heart Defects ◽  
Hispanic Women ◽  
Genetic Risk Score ◽  
Heart Defect ◽  
Maternal Hypertension ◽  
The Relationship

Abstract BACKGROUND Maternal hypertension has been associated with congenital heart defect occurrence in several studies. We assessed whether maternal genotypes associated with this condition were also associated with congenital heart defect occurrence. METHODS We used data from the National Birth Defects Prevention Study to identify non-Hispanic white (NHW) and Hispanic women with (cases) and without (controls) a pregnancy in which a select simple, isolated heart defect was present between 1999 and 2011. We genotyped 29 hypertension-related single nucleotide polymorphisms (SNPs). We conducted logistic regression analyses separately by race/ethnicity to assess the relationship between the presence of any congenital heart defect and each SNP and an overall blood pressure genetic risk score (GRS). All analyses were then repeated to assess 4 separate congenital heart defect subtypes. RESULTS Four hypertension-related variants were associated with congenital heart defects among NHW women (N = 1,568 with affected pregnancies). For example, 1 intronic variant in ARHGAP2, rs633185, was associated with conotruncal defects (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1–1.6). Additionally, 2 variants were associated with congenital heart defects among Hispanic women (N = 489 with affected pregnancies). The GRS had a significant association with septal defects (OR: 2.1, 95% CI: 1.2–3.5) among NHW women. CONCLUSIONS We replicated a previously reported association between rs633185 and conotruncal defects. Although additional hypertension-related SNPs were also associated with congenital heart defects, more work is needed to better understand the relationship between genetic risk for maternal hypertension and congenital heart defects occurrence.

scholarly journals Hyperactivity and Inattention in Young Patients Born With an Atrial Septal or Ventricular Septal Defect

2021 ◽  
Vol 9 ◽  
Author(s):  
Sara Hirani Lau-Jensen ◽  
Benjamin Asschenfeldt ◽  
Lars Evald ◽  
Vibeke E. Hjortdal
Keyword(s):  
Congenital Heart Defects ◽  
Congenital Heart Defect ◽  
Adhd Symptom ◽  
Congenital Heart ◽  
Rating Scales ◽  
Heart Defects ◽  
Close Relative ◽  
Adhd Symptoms ◽  
Heart Defect ◽  
Inattention And Hyperactivity

Background: Patients with congenital heart defects have a well-established risk of neuropsychiatric comorbidities. Inattention and hyperactivity are three to four times more frequent in children with complex congenital heart defects. We have previously shown a higher burden of overall attention deficit/hyperactivity disorder (ADHD) symptoms in adults with simple congenital heart defects as well. However, it is unknown whether the higher burden of ADHD symptoms is mainly driven by hyperactivity, inattention, or both.Methods: The participants [simple congenital heart defect = 80 (26.6 years old), controls = 36 (25.3 years old)] and a close relative for each (n = 107) responded to the long version of the Conners' Adults ADHD Rating Scales questionnaire. Our primary and secondary outcomes are mean T-scores in the ADHD scores and symptom sub-scores.Results: Patients with simple congenital heart defects reported a higher mean T-score at all three DSM-IV ADHD scores (ADHD—combined: 52.8 vs. 44.9, p = 0.007, ADHD—inattention: 55.5 vs. 46.4, p = 0.002, and ADHD—hyperactivity: 49.4 vs. 44.0, p = 0.03) and in all four ADHD symptom sub-scores (inattention/memory problems: 50.3 vs. 44.2, p = 0.001, hyperactivity/restlessness: 49.7 vs. 45.9, p = 0.03, impulsivity/emotional lability: 50.0 vs. 41.3, p = 0.001, and self-esteem problems: 53.8 vs. 46.3, p = 0.003). The results were maintained after the removal of outliers (incongruent responses), albeit the hyperactivity/restlessness ADHD symptom sub-score lost significance. Self- and informant ratings differed significantly on the ADHD—inattention score for the congenital heart defect group, where informants rated the ADHD—inattention scores better than the congenital heart defect patients rated themselves.Conclusions: Patients with a simple congenital heart defect have a higher symptom burden across all ADHD scores and all symptom sub-scores. The higher burden of ADHD is driven by both inattention and hyperactivity symptoms, though the inattention symptoms seem more prominent. Close relatives were less aware of the inattention symptoms than the congenital heart defect patients themselves. Routine screening for ADHD symptoms may be warranted to facilitate adequate help and guidance as these symptoms are easily overlooked.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03871881.

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