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PloS One 2019As academic achievement can have a major impact on the development of social inequalities we set out to explore how performance differences arise. Using data of the...
As academic achievement can have a major impact on the development of social inequalities we set out to explore how performance differences arise. Using data of the German twin study TwinLife, genetic and environmental effects on school grades in mathematics, German and the grade point average in two age cohorts (11 and 17 years old) were identified. Structural equation modelling on the data of 432 monozygotic and 529 dizygotic twin pairs as well as 317 siblings of the twins showed substantial genetic effects (up to 62%) in both cohorts on all three variables. Next to genetic influences, the twin-specific environment as well as non-shared environmental influences were found to explain the interindividual differences in mathematics and German as well as the grade point average. A cohort effect showing itself in higher heritability in the older cohort was found for mathematics and the grade point average but not for German. Moreover, we compared twins who were assigned to the same classroom to those twins who were assigned to different classrooms and found lower effects of the twin-specific shared environment in the latter group. Our study thereby contributes to the understanding of the etiology of interindividual differences in academic achievement in the numeracy and literacy domain in two age cohorts.
Topics: Academic Success; Adolescent; Age Factors; Child; Environment; Gene-Environment Interaction; Humans; Mathematics; Models, Genetic; Models, Theoretical; Schools; Siblings; Students; Twins, Dizygotic; Twins, Monozygotic
PubMed: 31891583
DOI: 10.1371/journal.pone.0225946 -
European Journal of Human Genetics :... Jun 2019The tendency to conceive spontaneous dizygotic (DZ) twins is a complex trait with important contributions from both environmental factors and genetic disposition. In...
The tendency to conceive spontaneous dizygotic (DZ) twins is a complex trait with important contributions from both environmental factors and genetic disposition. In earlier work, we identified the first two genes as maternal susceptibility loci for DZ twinning. The aim of this study was to identify genetic variants influencing multiple births and to genetically correlate the findings across a broad range of traits. We performed a genome-wide association study (GWAS) in 8962 participants with Caucasian ancestry from UK Biobank who reported being part of a multiple birth, and 409,591 singleton controls. We replicated the association between FSHB, SMAD3 and twinning in the gene-based (but not SNP-based) test, which had been established in previous genome-wide association analyses in mothers with dizygotic twin offspring. Additionally, we report a novel genetic variant associated with multiple birth, rs428022 at 15q23 (p = 2.84 × 10) close to two genes: PIAS1 and SKOR1. Finally, we identified meaningful genetic correlations between being part of a multiple birth and other phenotypes (anthropometric traits, health-related traits, and fertility-related measures). The outcomes of this study provide important new insights into the genetic aetiology of multiple births and fertility, and open up novel directions for fertility and reproduction research.
Topics: Adult; Aged; Aged, 80 and over; Biological Specimen Banks; Co-Repressor Proteins; Female; Genome-Wide Association Study; Humans; Male; Middle Aged; Multiple Birth Offspring; Protein Inhibitors of Activated STAT; Small Ubiquitin-Related Modifier Proteins; Twins, Dizygotic; Twins, Monozygotic; United Kingdom
PubMed: 30760885
DOI: 10.1038/s41431-019-0355-z -
Investigative Ophthalmology & Visual... Aug 2017To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension.
PURPOSE
To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension.
METHODS
This was a cross-sectional study of 50 monozygotic and 49 dizygotic, same-sex twin pairs aged 20 to 46 years. In 50°, disc-centered fundus photographs, the retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficients. Falconer's formula and quantitative genetic models were used to determine the genetic component of variation.
RESULTS
The mean fractal dimension did not differ statistically significantly between monozygotic and dizygotic twin pairs (1.505 vs. 1.495, P = 0.06), supporting that the study population was suitable for quantitative analysis of heritability. The intrapair correlation was markedly higher (0.505, P = 0.0002) in monozygotic twins than in dizygotic twins (0.108, P = 0.46), corresponding to a heritability h2 for the fractal dimension of 0.79. In quantitative genetic models, dominant genetic effects explained 54% of the variation and 46% was individually environmentally determined.
CONCLUSIONS
In young adult twins, the branching pattern of the retinal vessels demonstrated a higher structural similarity in monozygotic than in dizygotic twin pairs. The retinal vascular fractal dimension was mainly determined by genetic factors, which accounted for 54% of the variation. The genetically predetermination of the retinal vasculature may affect the retinal response to potential vascular disease in later life.
Topics: Adult; Cross-Sectional Studies; Female; Fractals; Humans; Male; Middle Aged; Quantitative Trait, Heritable; Retinal Vessels; Surveys and Questionnaires; Twins, Dizygotic; Twins, Monozygotic; Young Adult
PubMed: 28800646
DOI: 10.1167/iovs.17-22072 -
Twin Research and Human Genetics : the... Feb 2013The Boston University Twin Project (BUTP) is a multi-method, multi-situation, longitudinal study of early child temperament and related behaviors. The first phase of...
The Boston University Twin Project (BUTP) is a multi-method, multi-situation, longitudinal study of early child temperament and related behaviors. The first phase of this project focused primarily on activity level and comprised over 300 twin pairs assessed in the home and lab at ages 2 and 3. Subject recruitment, sample characteristics, and study procedures are described. A second phase broadens our focus to the development of multiple temperament dimensions and developmental outcomes in a new cohort of 300 twin pairs to be assessed at 3, 4, and 5 years of age. Recruitment is currently underway.
Topics: Boston; Child Development; Child, Preschool; Family; Humans; Longitudinal Studies; Patient Selection; Personality Development; Social Environment; Temperament; Twins, Dizygotic; Twins, Monozygotic; Universities
PubMed: 23046533
DOI: 10.1017/thg.2012.64 -
The Journal of Investigative Dermatology Sep 2000Polymorphic light eruption is classified as an acquired idiopathic photodermatosis, yet it appears to cluster in families, suggesting a possible genetic component. In...
Polymorphic light eruption is classified as an acquired idiopathic photodermatosis, yet it appears to cluster in families, suggesting a possible genetic component. In this study, we assess the heritability of polymorphic light eruption using the classical twin model. Polymorphic light eruption was investigated by a nurse-administered questionnaire in a sample of 420 pairs of adult female twins from St Thomas' Hospital UK Adult Twin Registry, including 119 monozygotic and 301 dizygotic pairs. Probandwise concordance for the presence and absence of disease was calculated and the heritability of polymorphic light eruption assessed by a quantitative genetic model fitting approach using Mx software. The prevalence of polymorphic light eruption was 21% and 18% in monozygotic and dizygotic twins, respectively. A family history of polymorphic light eruption in first-degree relatives (not including the cotwin) was present in 12% of affected twin pairs (where at least one twin had polymorphic light eruption) compared with 4% of unaffected twin pairs, providing evidence of familial clustering (p < 0.0001). The probandwise concordance for polymorphic light eruption was higher in monozygotic (0.72) than in dizygotic twin pairs (0.30), indicating a strong genetic effect. Quantitative genetic modeling found that a model comprising additive genetic (A) and unique environmental (E) factors provided the most parsimonious fit, although a dominant gene effect could also explain our data. In the AE model, 84% (95% confidence interval 65-94%) of the variance in susceptibility to polymorphic light eruption is attributed to additive genetic factors with the remaining 16% (95% confidence interval 6-35%) to unique environmental effects. These data establish a clear genetic influence in the expression of polymorphic light eruption and provide a basis for examining candidate genes that may be pathogenic in this common condition.
Topics: Adult; Aged; Diseases in Twins; Environmental Exposure; Female; Humans; Male; Middle Aged; Photosensitivity Disorders; Prevalence; Twins, Dizygotic; Twins, Monozygotic
PubMed: 10951285
DOI: 10.1046/j.1523-1747.2000.00079.x -
Annali Dell'Istituto Superiore Di Sanita 2019This study explores the association between sleep quality and emotional regulation, and investigates the genetic and environmental bases of this association. (Comparative Study)
Comparative Study
AIM
This study explores the association between sleep quality and emotional regulation, and investigates the genetic and environmental bases of this association.
METHODS
Three-hundred-eighty-two adolescent twins, from the Italian Twin Registry, and their parents filled the Youth Self-Report and Child Behavior Checklist questionnaires, from which the construct of Effortful Control (EC) was derived as a measure of emotional regulation. Twins were identified as "good" or "non-good" sleepers based on answers to the Sleep Disorders Questionnaire. EC levels were compared between same-sex sleep discordant twins.
RESULTS
A significant association was detected between EC scores and sleep quality. When controlling for shared (fetal or early life) environmental factors and genetic background in the discordant twin analysis, this association weakened in dizygotic twins and disappeared in monozygotic twins.
CONCLUSION
Results support the association between sleep quality and EC in adolescence; furthermore, they suggest that sleep quality and emotional regulation may depend on common genetic or environmental factors.
Topics: Adolescent; Adolescent Behavior; Attention; Diseases in Twins; Emotional Regulation; Female; Humans; Italy; Male; Psychology, Adolescent; Self Report; Self-Control; Sleep; Sleep Wake Disorders; Surveys and Questionnaires; Temperament; Twins, Dizygotic; Twins, Monozygotic
PubMed: 31264634
DOI: 10.4415/ANN_19_02_03 -
NeuroImage. Clinical 2022Cerebellar-cortical resting-state functional connectivity (rsFC) has been reported to be altered in cannabis users. However, this association may be due to genetic and...
Cerebellar-cortical resting-state functional connectivity (rsFC) has been reported to be altered in cannabis users. However, this association may be due to genetic and environmental confounding rather than a causal relationship between cannabis use and changes in rsFC. In this co-twin control study, linear mixed models were used to assess relationships between the number of lifetime cannabis uses (NLCU) and age of cannabis onset (ACO) with cerebellar-cortical rsFC. The rsFC with seven functional networks was evaluated in 147 monozygotic and 82 dizygotic twin pairs. Importantly, the use of genetically informed models in this twin sample facilitated examining whether shared genetic or environmental effects underlie crude associations between cannabis measures and connectivity. Individual-level phenotypic analyses (i.e., accounting for twin-pair non-independence) showed that individuals in the full sample with earlier ACO and higher NLCU had lower cerebellar rsFC within the VA, DA, and FP networks. Yet, there were no significant differences in cerebellar-cortical rsFC between monozygotic twins who were discordant for cannabis measures. These findings suggest shared genetic or environmental confounds contribute to associations between cannabis use and altered cerebellar-cortical rsFC, rather than unique causal impacts of cannabis use on cerebellar-cortical rsFC.
Topics: Humans; Cannabis; Twins, Dizygotic; Twins, Monozygotic; Age of Onset; Cerebellum
PubMed: 36451348
DOI: 10.1016/j.nicl.2022.103237 -
Scientific Reports Oct 2023Considerable evidence supports the role of present-moment attention, a central feature of mindfulness, in subjective wellbeing maintenance and enhancement. Yet it is not...
Considerable evidence supports the role of present-moment attention, a central feature of mindfulness, in subjective wellbeing maintenance and enhancement. Yet it is not clear why such a relation exists. This study examined the genetic and environmental contributions of present-moment attention to subjective wellbeing. Consistent with the "generalist genes hypothesis" and prior evidence, we hypothesized that presence and subjective wellbeing would show a substantial genetic correlation and smaller environmental correlation. Using a large epidemiological sample of healthy 16-year-old twins in the United Kingdom (N = 1136 monozygotic (MZ) and dizygotic (DZ) twin pairs), genetic overlap was found between presence and the cognitive component of subjective wellbeing (life satisfaction), and to a lesser extent, the affective component of subjective wellbeing (operationalized as happiness). The non-shared environmental overlap between these constructs was substantial. This study provides the first evidence known to us showing that present-centered attention, a primary component of mindfulness, has both genetic and environmental overlap with subjective wellbeing. The findings have implications for understanding mechanisms by which presence is associated with positive emotions and life satisfaction, and suggest, pending additional research, that mindfulness-based interventions to enhance wellbeing may be best suited to those with a genetic propensity toward mindful presence.
Topics: Humans; Adolescent; Twins, Dizygotic; Happiness; Mindfulness; United Kingdom; Twins, Monozygotic
PubMed: 37838734
DOI: 10.1038/s41598-023-42810-x -
Archives of General Psychiatry Feb 2009Structural neuroimaging studies suggest the presence of subtle abnormalities in the brains of patients with bipolar disorder. The influence of genetic and/or...
CONTEXT
Structural neuroimaging studies suggest the presence of subtle abnormalities in the brains of patients with bipolar disorder. The influence of genetic and/or environmental factors on these brain abnormalities is unknown.
OBJECTIVE
To investigate the contribution of genetic and environmental factors on brain volume in bipolar disorder.
DESIGN
Magnetic resonance imaging (1.5 T) brain scans of monozygotic (MZ) or dizygotic (DZ) twins concordant and discordant for bipolar disorder were compared with healthy twin pairs.
SETTING
Subjects were recruited from the population, the Netherlands Twin Register, and the twin pair cohort at the University Medical Center Utrecht, Utrecht, The Netherlands.
PARTICIPANTS
A total of 234 subjects including 50 affected twin pairs (9 MZ concordant; 15 MZ discordant; 4 DZ concordant; 22 DZ discordant) and 67 healthy twin pairs (39 MZ and 28 DZ) were included.
MAIN OUTCOME MEASURES
Volumes of the intracranium, cerebrum, cerebellum, lateral and third ventricle, and gray and white matter from the cerebrum and frontal, parietal, temporal, and occipital lobes, both with and without correction for lithium use. To estimate the influence of additive genetic, common, and unique environmental factors, structural equation modeling was applied.
RESULTS
Bipolar disorder was associated with a decrease in total cortical volume. Decreases in white matter were related to the genetic risk of developing bipolar disorder (bivariate heritability, 77%; 95% confidence interval, 38% to 100%). Significant environmental correlations were found for cortical gray matter. These relationships all became more pronounced when data were corrected for lithium use.
CONCLUSIONS
Focusing on genes controlling white matter integrity may be a fruitful strategy in the quest to discover genes implicated in bipolar disorder. Elucidating the mechanism by which lithium attenuates brain matter loss may lead to the development of neuroprotective drugs.
Topics: Adult; Antimanic Agents; Bipolar Disorder; Brain; Cerebral Cortex; Cohort Studies; Diseases in Twins; Female; Genetic Predisposition to Disease; Genotype; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Lithium Carbonate; Magnetic Resonance Imaging; Male; Middle Aged; Netherlands; Organ Size; Phenotype; Social Environment; Twins, Dizygotic; Twins, Monozygotic; Young Adult
PubMed: 19188536
DOI: 10.1001/archgenpsychiatry.2008.541 -
EBioMedicine Mar 2022Previous findings for the genetic and environmental contributions to DNA methylation variation were for limited age ranges only. We investigated the lifespan...
BACKGROUND
Previous findings for the genetic and environmental contributions to DNA methylation variation were for limited age ranges only. We investigated the lifespan contributions and their implications for human health for the first time.
METHODS
1,720 monozygotic twin (MZ) pairs and 1,107 dizygotic twin (DZ) pairs aged 0-92 years were included. Familial correlations (i.e., correlations between twins) for 353,681 methylation sites were estimated and modelled as a function of twin pair cohabitation history.
FINDINGS
The methylome average familial correlation was around zero at birth (MZ pair: -0.01; DZ pair: -0.04), increased with the time of twins living together during childhood at rates of 0.16 (95%CI: 0.12-0.20) for MZ pairs and 0.13 (95%CI: 0.07-0.20) for DZ pairs per decade, and decreased with the time of living apart during adulthood at rates of 0.026 (95%CI: 0.019-0.033) for MZ pairs and 0.027 (95%CI: 0.011-0.043) for DZ pairs per decade. Neither the increasing nor decreasing rate differed by zygosity (both P>0.1), consistent with cohabitation environment shared by twins, rather than genetic factors, influencing the methylation familial correlation changes. Familial correlations for 6.6% (23,386/353,681) sites changed with twin pair cohabitation history. These sites were enriched for high heritability, proximal promoters, and epigenetic/genetic associations with various early-life factors and late-life health conditions.
INTERPRETATION
Early life strongly influences DNA methylation variation across the lifespan, and the effects are stronger for heritable sites and sites biologically relevant to the regulation of gene expression. Early life could affect late-life health through influencing DNA methylation.
FUNDING
Victorian Cancer Agency, Cancer Australia, Cure Cancer Foundation.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; DNA Methylation; Epigenomics; Humans; Infant; Infant, Newborn; Longevity; Middle Aged; Twins, Dizygotic; Twins, Monozygotic; Young Adult
PubMed: 35301182
DOI: 10.1016/j.ebiom.2022.103927