Twin Research And Human Genetics[JOURNAL]
Sun
200 papers
Partnership with the University of São Paulo Panel of Twins: A Four-City Tour and More / Twin Research Reviews: Twin Research on Binge Eating; Twins' Physical Outcomes Linked to Different Diets; Working Conditions and Sickness Absence in Swedish Twins; Facial Morphology Differences in Monozygotic Twins / Human Interest and Importance: Michigan Family Forced to Adopt Their Own Twins; Ethics of Hiring a Surrogate to Bear Twins; Twin Survivors of the Israel-Hamas War; Twin Pregnancy with Double Uterus; Three Twin Pairs on Same Women's Soccer Team.
Segal NL
Twin Res Hum Genet · 2024 Feb · PMID 38380982 · Publisher ↗
This article begins with an overview of twin research in Brazil, initiated by the University of São Paulo Panel of Twins. I met with many new research collaborators and students while on a fall 2023 four-city lecture tou...
This article begins with an overview of twin research in Brazil, initiated by the University of São Paulo Panel of Twins. I met with many new research collaborators and students while on a fall 2023 four-city lecture tour in that country. A meeting with a world-famous surgeon who recently separated craniopagus conjoined twin pairs is also described. This overview is followed by summaries of twin research on binge eating, twins' physical outcomes linked to different diets, working conditions and sickness absence in Swedish Twins and facial morphology differences in monozygotic twins. The final section of this article provides a sampling of human interest stories with important implications. They include a Michigan family forced to adopt their own twins, ethical issues surrounding the hiring of a surrogate to bear twins; twin survivors of the Israel-Hamas war, a twin pregnancy with a double uterus, and three twin pairs on the same women's soccer team.
Trends in Twin Births and Survival in Bangladesh: An Analysis of Half a Century of Evidence.
Hossain KZ, Hasan I
Twin Res Hum Genet · 2024 Jun · PMID 38343356 · Publisher ↗
This study assessed the trends in twin births and their survival in Bangladesh by analyzing over a quarter million live births during 1970-2018, pooled from all eight rounds of the Bangladesh Demographic and Health Surve...
This study assessed the trends in twin births and their survival in Bangladesh by analyzing over a quarter million live births during 1970-2018, pooled from all eight rounds of the Bangladesh Demographic and Health Survey. In these five decades, the twinning rate increased by 1.5 times, from 5.8 to 8.6 twins per 1000 maternities. The decadal twinning rates varied across maternal age, parity, body mass index, household wealth index, and geographic region. The gap in decadal neonatal, infant, and under-five cumulative survival probability between singleton and multiple births was found to be closing, using Kaplan-Meier curves. Child mortality decreased by 80% and 60% in singleton and multiple births respectively. However, the absolute size of child mortality in multiple births remained six times higher than in singletons and was concentrated in the neonatal period. The share of multiple births surged in all types of child mortality. We predict a further and faster rise in multiple births in the coming decades in the face of upward trends in maternal age overlapping with higher parities, education, career prospects, contraceptive use, and the future demand-supply of assisted reproductive technology. A particular focus on the improvement of perinatal and neonatal care with wider availability is warranted. Otherwise, increased multiple births might raise child mortality and create public health challenges.
Family History of Twinning and Fertility Traits in Nigerian Mothers of Dizygotic Twins.
Hur YM, Martin N, Oginni O … +3 more , Boomsma D, Hubers N, Mbarek H
Twin Res Hum Genet · 2024 Feb · PMID 38291712 · Publisher ↗
Familial twinning and fertility traits were investigated in Nigerian mothers of dizygotic (DZ) twins (MoDZT; = 972) and controls ( = 525) who responded to our person-to-person interview, which included questions on preg...
Familial twinning and fertility traits were investigated in Nigerian mothers of dizygotic (DZ) twins (MoDZT; = 972) and controls ( = 525) who responded to our person-to-person interview, which included questions on pregnancy history and family history of DZ twinning. Controls were defined as women who are not twins themselves and do not have twins in their first-degree relatives. Over 95% of the participants were Yoruba. We found that Nigerian MoDZT had an average of 4.0 (±2.6) pairs of twins among their relatives, and of these, the prevalence of DZ twins was significantly higher than that of monozygotic (MZ) twins (45.9% vs. 25.8%). Controls had an average of 0.5 (±0.4) pairs, and over 95% of the controls had no twins in their relatives. These results suggest genetic influences on DZ twinning in Nigerians. MoDZT were significantly younger in their mean age at first child, and had higher parity than controls, suggesting increased fertility in MoDZT. As compared to mothers with a single set of twins, mothers ( = 130) with multiple sets had significantly more twins among their relatives (5.4 pairs vs. 3.7 pairs) and had their first twins at a younger age (28.4 vs. 30.7 years), indicating that mothers with multiple sets of twins might have higher genetic propensity for twinning associated with earlier age at twin pregnancy. Our findings argue for genomewide association studies for DZ twinning in Nigerians, and may help to develop intervention strategies to overcome infertility/subfertility problems.
DNA Methylation Mediated the Association of Body Mass Index With Blood Pressure in Chinese Monozygotic Twins.
Yao J, Ning F, Wang W … +1 more , Zhang D
Twin Res Hum Genet · 2024 Feb · PMID 38291711 · Publisher ↗
Obesity is an established risk factor for hypertension, but the mechanisms are only partially understood. We examined whether body mass index (BMI)-related DNA methylation (DNAm) variation would mediate the association o...
Obesity is an established risk factor for hypertension, but the mechanisms are only partially understood. We examined whether body mass index (BMI)-related DNA methylation (DNAm) variation would mediate the association of BMI with blood pressure (BP). We first conducted a genomewide DNA methylation analysis in monozygotic twin pairs to detect BMI-related DNAm variation and then evaluated the mediating effect of DNAm on the relationship between BMI and BP levels using the causal inference test (CIT) method and mediation analysis. Ontology enrichment analysis was performed for CpGs using the GREAT tool. A total of 60 twin pairs for BMI and systolic blood pressure (SBP) and 58 twin pairs for BMI and diastolic blood pressure (DBP) were included. BMI was positively associated with SBP (β = 1.86, = .0004). The association between BMI and DNAm of 85 CpGs reached < 1×10 level. Eleven BMI-related differentially methylated regions (DMRs) within , , , , , , , , , and were found. Of the 85 CpGs, 9 mapped to , , , , , and were significantly associated with SBP levels. Of the 9 CpGs, 2 within negatively mediated the association between BMI and SBP, with a mediating effect of -0.24 (95% CI [-0.65, -0.01]). BMI was also positively associated with DBP (β = 0.60, = .0495). The association between BMI and DNAm of 193 CpGs reached < 1×10 level. Twenty-five BMI-related DMRs within , , , , , , and were found. Of the 193 CpGs, 33 mapped to , , , , , , and were significantly associated with DBP levels. Of the 33 CpGs, 12 within , , , , , , and negatively mediated the association between BMI and DBP, with a total mediation effect of -0.66 (95% CI [-1.07, -0.30]). Interestingly, BMI might also negatively mediate the association between the DNAm of most CpG mediators mentioned above and BP. The mediating effect of DNAm was also found when stratified by sex. In conclusion, DNAm variation may partially negatively mediate the association of BMI with BP. Our findings may provide new clues to further elucidate the pathogenesis of obesity to hypertension and identify new diagnostic biomarkers and therapeutic targets for hypertension.
Association Between Dysmenorrhea and Risk of Epilepsy in East Asian Populations: A Bidirectional Two-Sample Mendelian Randomization Study.
Ren Y, Zhang J, Chen T … +7 more , Chen J, Liao Y, Liu T, Yang L, Liu C, Liu X, Liu B
Twin Res Hum Genet · 2023 Dec · PMID 38099415 · Publisher ↗
Dysmenorrhea is associated with epilepsy. Existing evidence is mostly limited to observational studies, which are liable to confounding and bias. This study investigated the causal relevance of dysmenorrhea on epilepsy u...
Dysmenorrhea is associated with epilepsy. Existing evidence is mostly limited to observational studies, which are liable to confounding and bias. This study investigated the causal relevance of dysmenorrhea on epilepsy using Mendelian randomization (MR). We extracted instrumental variants for dysmenorrhea and epilepsy from published genomewide association study data, focusing on individuals of East Asian descent. A comprehensive suite of MR estimations and sensitivity analyses was performed to ensure the robustness of the findings. Each outcome database was analyzed separately in both directions. For dysmenorrhea and epilepsy, 7 and 3 genetic variants respectively were selectively extracted as instrumental variants. The results suggest that dysmenorrhea is causally associated with an elevated risk of epilepsy (inverse variance weighted [IVW]: = 1.26; 95% CI [1.07, 1.47]; = 4.42 × 10); conversely, no strong evidence was found to corroborate that epilepsy exerts a causal effect on the incidence of dysmenorrhea (IVW: = 1.04; 95% CI [0.82, 1.33]; = .72). These findings provide novel insights into the causal relationship between dysmenorrhea and epilepsy, which may have implications for clinical decision-making in patients with epilepsy and dysmenorrhea.
Comprehensive Multiomics Analysis of Monozygotic Twin Discordant for Double Outlet Right Ventricle.
Liu Z, Li N, Pan X … +11 more , Li J, Li S, Li Q, Li P, Deng Y, Chen F, Jiang H, Wang W, Mu D, Yu P, Zhu J
Twin Res Hum Genet · 2023 Dec · PMID 38099413 · Publisher ↗
The objective of this study was to understand and measure epigenetic changes associated with the occurrence of CHDs by utilizing the discordant monozygotic twin model. A unique set of monozygotic twins discordant for dou...
The objective of this study was to understand and measure epigenetic changes associated with the occurrence of CHDs by utilizing the discordant monozygotic twin model. A unique set of monozygotic twins discordant for double-outlet right ventricles (DORVs) was used for this multiomics study. The cardiac and muscle tissue samples from the twins were subjected to whole genome sequencing, whole genome bisulfite sequencing, RNA-sequencing and liquid chromatography-tandem mass spectrometry analysis. Sporadic DORV cases and control fetuses were used for validation. Global hypomethylation status was observed in heart tissue samples from the affected twins. Among 36,228 differentially methylated regions (DMRs), 1097 DMRs involving 1039 genes were located in promoter regions. A total of 419 genes, and lncRNA-mRNA pairs involved 30 genes, and 62 proteins were significantly differentially expressed. Multiple omics integrative analysis revealed that five genes, including , , , , and , and three pathways, including ECM-receptor interaction, focal adhesion and TGF-β signaling pathway, exhibited differences at all three levels. This study demonstrates a multiomics profile of discordant twins and explores the possible mechanism of DORV development. Global hypomethylation might be associated with the risk of CHDs. Specific genes and specific pathways, particularly those involving ECM-receptor interaction, focal adhesion and TGF-β signaling, might be involved in the occurrence of CHDs.
National Trends in Suicides and Male Twin Live Births in the US, 2003 to 2019: An Updated Test of Collective Optimism and Selection in Utero.
Singh P, Gailey S, Das A … +1 more , Bruckner TA
Twin Res Hum Genet · 2023 Dec · PMID 38099411 · Full text
Prior research based on Swedish data suggests that collective optimism, as measured by monthly incidence of suicides, correlates inversely with against male twins in a population. We test this finding in the US, which r...
Prior research based on Swedish data suggests that collective optimism, as measured by monthly incidence of suicides, correlates inversely with against male twins in a population. We test this finding in the US, which reports the highest suicide rate of all high-income countries, and examine whether monthly changes in overall suicides precede changes in the ratio of male twin to male singleton live births. Consistent with prior work, we also examine as a key independent variable, suicides among women aged 15-49 years. We retrieved monthly data on suicides and the ratio of male twin to singleton live births from CDC WONDER, 2003 to 2019, and applied Box-Jenkins iterative time-series routines to detect and remove autocorrelation from both series. Results indicate that a 1% increase in monthly change in overall suicides precedes a 0.005 unit decline in male twin live births ratio 6 months later (coefficient = -.005, value = .004). Results remain robust to use of suicides among reproductive-aged women as the independent variable (coefficient = -.0012, value = .014). Our study lends external validity to prior research and supports the notion that a decline in collective optimism corresponds with greater selection in utero.
GWAS of Dizygotic Twinning in an Enlarged Australian Sample of Mothers of DZ Twins.
Gordon SD, Duffy DL, Whiteman DC … +12 more , Olsen CM, McAloney K, Adsett JM, Garden NA, Cross SM, List-Armitage SE, Brown J, Beck JJ, Mbarek H, Medland SE, Montgomery GW, Martin NG
Twin Res Hum Genet · 2023 Dec · PMID 37994447 · Publisher ↗
Female fertility is a complex trait with age-specific changes in spontaneous dizygotic (DZ) twinning and fertility. To elucidate factors regulating female fertility and infertility, we conducted a genome-wide association...
Female fertility is a complex trait with age-specific changes in spontaneous dizygotic (DZ) twinning and fertility. To elucidate factors regulating female fertility and infertility, we conducted a genome-wide association study (GWAS) on mothers of spontaneous DZ twins (MoDZT) versus controls (3273 cases, 24,009 controls). This is a follow-up study to the Australia/New Zealand (ANZ) component of that previously reported (Mbarek et al., 2016), with a sample size almost twice that of the entire discovery sample meta-analysed in the previous article (and five times the ANZ contribution to that), resulting from newly available additional genotyping and representing a significant increase in power. We compare analyses with and without male controls and show unequivocally that it is better to include male controls who have been screened for recent family history, than to use only female controls. Results from the SNP based GWAS identified four genomewide significant signals, including one novel region, (Zinc Finger Protein, FOG Family Member 1), on chromosome 16. Previous signals near (Follicle Stimulating Hormone beta subunit) and (SMAD Family Member 3) were also replicated (Mbarek et al., 2016). We also ran the GWAS with a dominance model that identified a further locus on chr 5. These results have been contributed to the International Twinning Genetics Consortium for inclusion in the next GWAS meta-analysis (Mbarek et al., in press).
Born Apart, but Raised Together: Twins Delivered in Different Countries/Twin Research Reviews: Hallermann-Streiff Syndrome in Monozygotic (MZ) Twins; Effects of Technology on Conjoined Twin Separation; Reciprocal DIEP Transplantation Between MZ Twins; Guidelines for Multifetal Management/Media Reports: Book by World's Oldest Auschwitz-Birkenau Twin Survivor; Passing of Ian Wilmut; Zhores Medvedev Was an Identical Twin; More Gay Fathers with Twin Sons; Twins and Siblings Admitted to Medical School; First and Fourth Records for Major League Baseball Twins.
Segal NL
Twin Res Hum Genet · 2023 Dec · PMID 37965686 · Publisher ↗
The circumstances and subsequent life events of the first twins to have been born in different countries are examined. Given that both twins were born in the United Kingdom, their common citizenship was never questioned....
The circumstances and subsequent life events of the first twins to have been born in different countries are examined. Given that both twins were born in the United Kingdom, their common citizenship was never questioned. In contrast, twins born in Canada to a legally married gay transnational couple - composed of one American and one Israeli - were assigned as citizens of different nations and their parents were regarded as if unmarried. This essay is followed by reviews of research on the Hallermann-Streiff syndrome in monozygotic (MZ) twins, the effects of technology on conjoined twin separation, reciprocal deep inferior epigastric perforator (DIEP) transplantation in MZ twins and new guidelines for managing multifetal pregnancies. Finally, media reports on a book by the world's oldest Auschwitz-Birkenau twin survivor, the passing of Dr Ian Wilmut, the identical twinship of Zhores Medvedev, another case of gay fathers with twin sons, twins and siblings admitted to medical school, and the first and fourth records for major league baseball twins are presented.
Genetic and Familial Influences on Self-Perception in Early Childhood and Self-Esteem in Adulthood: A Cross-Sectional Analysis.
Marshall RL, DiLalla LF, Harbke CR … +1 more , Pali EC
Twin Res Hum Genet · 2023 Dec · PMID 37859614 · Publisher ↗
Self-perception in early childhood and self-esteem in adulthood are related to a variety of aspects of psychological wellbeing. The goal of the present study was to examine genetic and familial influences on self-percept...
Self-perception in early childhood and self-esteem in adulthood are related to a variety of aspects of psychological wellbeing. The goal of the present study was to examine genetic and familial influences on self-perception and self-esteem in separate samples of children (153 twin pairs of 5-year-olds) and adults (753 twin pairs between the ages of 25-75 years). Genetic common factor modeling showed that three facets of self-perception (physical competence, peer acceptance, and maternal acceptance) loaded onto a single heritable factor in children. Multilevel modeling showed no effects of self or co-twin sex on self-perception, but authoritative parenting style was negatively related to self-perception in boys. Similarly, in Study 2, with the adult sample, five self-esteem items loaded on a single heritable factor with no effects of co-twin sex on adult self-esteem. Remembered maternal affection, paternal affection, and maternal discipline were positively related to self-esteem in adults; maternal affection was especially significant for women. The reversal in direction of parenting effects between early childhood and adulthood suggests that parents may play different roles in shaping how children and adults think of themselves. These results suggest that self-perception in childhood and self-esteem in adulthood are both influenced by genetic and environmental factors and that parenting is an important environmental factor for both children and adults.
Cap Analysis of Gene Expression Clarifies Transcriptomic Divergence Within Monozygotic Twin Pairs.
Katoh H, Asai H, Takemoto K … +5 more , Tomizawa R, Honda C, Watanabe M, Osaka Twin Research Group, Honda T
Twin Res Hum Genet · 2023 Aug · PMID 37845828 · Publisher ↗
Phenotypic variation is the result of gene expression based on complex interaction between genetic and environmental factors. It is well known that genetic and environmental factors influence gene expression, but our und...
Phenotypic variation is the result of gene expression based on complex interaction between genetic and environmental factors. It is well known that genetic and environmental factors influence gene expression, but our understanding of their relative importance remains limited. To obtain a hint for the understanding of their contributions, we took advantage of monozygotic twins, as they share genetic and shared environmental factors but differ in nonshared factors, such as environmental differences and stochastic factors. In this study, we performed cap analysis of gene expression on three pairs of twins and clustered each individual based on their expression profiles of annotated genes. The dendrogram of annotated gene transcripts showed a monophyletic clade for each twin pair. We also analyzed the expression of retrotransposons, such as human endogenous retroviruses (HERVs) and long interspersed nuclear elements (LINEs), given their abundance in the genome. Clustering analyses demonstrated that HERV and LINE expression diverged even within monozygotic twin pairs. Thus, HERVs and LINEs are more susceptible to nonshared factors than annotated genes. Motif analysis of differentially expressed annotated genes suggests that specificity protein/Krüppel-like factor family transcription factors are involved in the expression divergence of annotated gene influenced by nonshared factors. Collectively, our findings suggest that expressions of annotated genes and retrotransposons are differently regulated, and that the expression of retrotransposons is more susceptible to nonshared factors than annotated genes.
Estimating the Genetic Contribution to Astigmatism and Myopia in the Mexican Population.
Román-López TV, García-Vilchis B, Murillo-Lechuga V … +15 more , Chiu-Han E, López-Camaño X, Aldana-Assad O, Diaz-Torres S, Caballero-Sánchez U, Ortega-Mora I, Ramírez-González D, Zenteno D, Espinosa-Valdés Z, Tapia-Atilano A, Pradel-Jiménez S, Rentería ME, Medina-Rivera A, Ruiz-Contreras AE, Alcauter S
Twin Res Hum Genet · 2023 Aug · PMID 37842863 · Publisher ↗
Astigmatism and myopia are two common ocular refractive errors that can impact daily life, including learning and productivity. Current knowledge suggests that the etiology of these conditions is the result of a complex...
Astigmatism and myopia are two common ocular refractive errors that can impact daily life, including learning and productivity. Current knowledge suggests that the etiology of these conditions is the result of a complex interplay between genetic and environmental factors. Studies in populations of European ancestry have demonstrated a higher concordance of refractive errors in monozygotic (MZ) twins compared to dizygotic (DZ) twins. However, there is a lack of studies on genetically informative samples of multi-ethnic ancestry. This study aimed to estimate the genetic contribution to astigmatism and myopia in the Mexican population. A sample of 1399 families, including 243 twin pairs and 1156 single twins, completed a medical questionnaire about their own and their co-twin's diagnosis of astigmatism and myopia. Concordance rates for astigmatism and myopia were estimated, and heritability and genetic correlations were determined using a bivariate ACE Cholesky decomposition method, decomposed into A (additive genetic), C (shared environmental) and E (unique environmental) components. The results showed a higher concordance rate for astigmatism and myopia for MZ twins (.74 and .74, respectively) than for DZ twins (.50 and .55). The AE model, instead of the ACE model, best fitted the data. Based on this, heritability estimates were .81 for astigmatism and .81 for myopia, with a cross-trait genetic correlation of A = .80, nonshared environmental correlation E = .89, and a phenotypic correlation of P = .80. These results are consistent with previous findings in other populations, providing evidence for a similar genetic architecture of these conditions in the multi-ethnic Mexican population.
Effects of Genetic Relatedness of Kin Pairs on Univariate ACE Model Performance.
Lyu X, Garrison SM
Twin Res Hum Genet · 2023 Aug · PMID 37799059 · Full text
The current study explored the impact of genetic relatedness differences (ΔH) and sample size on the performance of nonclassical ACE models, with a focus on same-sex and opposite-sex twin groups. The ACE model is a stati...
The current study explored the impact of genetic relatedness differences (ΔH) and sample size on the performance of nonclassical ACE models, with a focus on same-sex and opposite-sex twin groups. The ACE model is a statistical model that posits that additive genetic factors (A), common environmental factors (C), and specific (or nonshared) environmental factors plus measurement error (E) account for individual differences in a phenotype. By extending Visscher's (2004) least squares paradigm and conducting simulations, we illustrated how genetic relatedness of same-sex twins (H) influences the statistical power of additive genetic estimates (A), AIC-based model performance, and the frequency of negative estimates. We found that larger H and increased sample sizes were positively associated with increased power to detect additive genetic components and improved model performance, and reduction of negative estimates. We also found that the common solution of fixing the common environment correlation for sex-limited effects to .95 caused slightly worse model performance under most circumstances. Further, negative estimates were shown to be possible and were not always indicative of a failed model, but rather, they sometimes pointed to low power or model misspecification. Researchers using kin pairs with ΔH less than .5 should carefully consider performance implications and conduct comprehensive power analyses. Our findings provide valuable insights and practical guidelines for those working with nontwin kin pairs or situations where zygosity is unavailable, as well as areas for future research.
C. C. Li and Quasi-Random Mating.
Stark AE
Twin Res Hum Genet · 2023 Aug · PMID 37706311 · Publisher ↗
A simple model by which Hardy-Weinberg proportions are attained in a single generation while maintaining gene frequencies is stated and illustrated. The title 'Quasi-random mating' is proposed. Confusion about the Hardy-...
A simple model by which Hardy-Weinberg proportions are attained in a single generation while maintaining gene frequencies is stated and illustrated. The title 'Quasi-random mating' is proposed. Confusion about the Hardy-Weinberg principle can be avoided only if there is clear separation between the basic deterministic model and factors influencing a population's structure. Eighty years passed before C. C. Li coined the term 'pseudo-random mating'. The lesson taught by Li has not been taken on board.
A 10-Year Observational Study on Twin Pregnancy: Role of Fetal Sex Pairing on Obstetric Outcome.
Vannuccini S, Bolzonella S, Colucci C … +3 more , Nicchi C, Strambi N, Di Tommaso M
Twin Res Hum Genet · 2023 Aug · PMID 37706309 · Publisher ↗
Fetal sex contributes to the determination of obstetric outcome, as pregnancies carrying male babies seem to have an increased risk of maternal-fetal complications. Most studies have been conducted on singleton pregnanci...
Fetal sex contributes to the determination of obstetric outcome, as pregnancies carrying male babies seem to have an increased risk of maternal-fetal complications. Most studies have been conducted on singleton pregnancies, whereas less evidence is available for twins. A 10-year retrospective observational study was conducted on a cohort of 1180 women with twin pregnancy delivered at a single tertiary hospital. Clinical data on maternal characteristics, and obstetric and neonatal outcomes were collected, and the analysis was performed on monochorionic (MC) and dichorionic (DC) diamniotic twins separately. The group of DC twins included 837 cases, and those conceived by assisted reproductive technologies (ART) were more likely to have one or both female fetuses rather than males. The incidence of hypertensive disorders of pregnancy (HDP) was higher in same-sex pairs than in opposite-sex pairs. No differences were found regarding other obstetric and neonatal outcomes among the three sex-pairing groups. The MC twins group included 228 cases, and in female-carrying pregnancies a higher incidence of gestational diabetes (GDM) was observed compared to the male group. Furthermore, male pairs had significantly lower Apgar scores than females. Fetal sex seems to have a mild effect in twins compared to singleton pregnancies, suggesting a more complex set of factors contributing to pregnancy outcome in multiple pregnancies. However, we observed a higher incidence of HDP among same-sex DC pairs, a higher rate of GDM among MC female-female pairs, and a worse adaptation to extrauterine life among male-male pairs in MC twins.
Early Spontaneous Twinning Recorded By Time-Lapse.
Matorras R, Vendrell A, Ferrando M … +1 more , Larreategui Z
Twin Res Hum Genet · 2023 Jun · PMID 37655615 · Publisher ↗
Monozygotic twins (MZT) are 2.5 times more frequent in ART than in natural conceptions. A number of ART-related mechanisms have been probably linked with MZT. Studies that retrospectively analyze the time-lapse (TL) reco...
Monozygotic twins (MZT) are 2.5 times more frequent in ART than in natural conceptions. A number of ART-related mechanisms have been probably linked with MZT. Studies that retrospectively analyze the time-lapse (TL) records resulting in MZT suggest that some morphokinetic traits of the inner cell mass and the trophectoderm could be predictors of MZT, but results are controversial. We present the complete TL record of one case of MZT that split itself at the very moment of the division into two cells, with one of the cells coming out through a hole in the zona pellucida (ZP). Both resulting embryos developed normally, and were vitrified. It is suggested that the hole in the ZP may facilitate the extrusion of some cells of the <day 4 embryo and that this cell development is not constrained by being inside the ZP. Despite the lack of the inhibition of the ZP itself or the influence of the other embryo cells, the totipotent cell was then able to develop correctly from the start. Moreover, the embryo inside the ZP compensated for the loss of this cell apparently without problems. Our findings are discussed in the context of previous literature and ethical problems are addressed.
Mitochondrial DNA Copy Number and Heteroplasmy in Monozygotic Twins Discordant for Schizophrenia.
Win PW, Singh SM, Castellani CA
Twin Res Hum Genet · 2023 Aug · PMID 37655526 · Publisher ↗
Schizophrenia (SZ) is a severe, complex, and common mental disorder with high heritability (80%), an adult age of onset, and high discordance (∼50%) in monozygotic twins (MZ). Extensive studies on familial and non-famili...
Schizophrenia (SZ) is a severe, complex, and common mental disorder with high heritability (80%), an adult age of onset, and high discordance (∼50%) in monozygotic twins (MZ). Extensive studies on familial and non-familial cases have implicated a number of segregating mutations and de novo changes in SZ that may include changes to the mitochondrial genome. Yet, no single universally causal variant has been identified, highlighting its extensive genetic heterogeneity. This report specifically focuses on the assessment of changes in the mitochondrial genome in a unique set of monozygotic twins discordant (MZD) for SZ using blood. Genomic DNA from six pairs of MZD twins and two sets of parents ( = 16) was hybridized to the Affymetrix Human SNP Array 6.0 to assess mitochondrial DNA copy number (mtDNA-CN). Whole genome sequencing (WGS) and quantitative polymerase chain reaction (qPCR) was performed for a subset of MZD pairs and their parents and was also used to derive mtDNA-CN estimates. The WGS data were further analyzed to generate heteroplasmy (HP) estimates. Our results show that mtDNA-CN estimates for within-pair and mother-child differences were smaller than comparisons involving unrelated individuals, as expected. MZD twins showed discordance in mtDNA-CN estimates and displayed concordance in directionality of differences for mtDNA-CN across all technologies. Further, qPCR performed better than Affymetrix in estimating mtDNA-CN based on relatedness. No reliable differences in HP were detected between MZD twins. The within-MZD differences in mtDNA-CN observed represent postzygotic somatic changes that may contribute to discordance of MZ twins for diseases, including SZ.
The Co-Twin Control Design: Implementation and Methodological Considerations.
Gonggrijp BMA, van de Weijer SGA, Bijleveld CCJH … +2 more , van Dongen J, Boomsma DI
Twin Res Hum Genet · 2023 Aug · PMID 37655521 · Publisher ↗
Establishing causal relationships in observational studies is an important step in research and policy decision making. The association between an exposure and an outcome can be confounded by multiple factors, often maki...
Establishing causal relationships in observational studies is an important step in research and policy decision making. The association between an exposure and an outcome can be confounded by multiple factors, often making it hard to draw causal conclusions. The co-twin control design (CTCD) is a powerful approach that allows for the investigation of causal effects while controlling for genetic and shared environmental confounding factors. This article introduces the CTCD and offers an overview of analysis methods for binary and continuous outcome and exposure variables. Tools for data simulation are provided, along with practical guidance and accompanying scripts for implementing the CTCD in R, SPSS, and Stata. While the CTCD offers valuable insights into causal inference, it depends on several assumptions that are important when interpreting CTCD results. By presenting a broad overview of the CTCD, this article aims to equip researchers with actionable recommendations and a comprehensive understanding of the design's strengths and limitations.
Genetic and Environmental Influences on Blood Pressure and Serum Lipids Across Age-Groups.
Miao K, Wang Y, Cao W … +14 more , Lv J, Yu C, Huang T, Sun D, Liao C, Pang Y, Hu R, Pang Z, Yu M, Wang H, Wu X, Liu Y, Gao W, Li L
Twin Res Hum Genet · 2023 Jun · PMID 37650338 · Publisher ↗
Aging plays a crucial role in the mechanisms of the impacts of genetic and environmental factors on blood pressure and serum lipids. However, to our knowledge, how the influence of genetic and environmental factors on th...
Aging plays a crucial role in the mechanisms of the impacts of genetic and environmental factors on blood pressure and serum lipids. However, to our knowledge, how the influence of genetic and environmental factors on the correlation between blood pressure and serum lipids changes with age remains to be determined. In this study, data from the Chinese National Twin Registry (CNTR) were used. Resting blood pressure, including systolic and diastolic blood pressure (SBP and DBP), and fasting serum lipids, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TGs) were measured in 2378 participants (1189 twin pairs). Univariate and bivariate structural equation models examined the genetic and environmental influences on blood pressure and serum lipids among three age groups. All phenotypes showed moderate to high heritability (0.37-0.59) and moderate unique environmental variance (0.30-0.44). The heritability of all phenotypes showed a decreasing trend with age. Among all phenotypes, SBP and DBP showed a significant monotonic decreasing trend. For phenotype-phenotype pairs, the phenotypic correlation (Rph) of each pair ranged from -0.04 to 0.23, and the additive genetic correlation (Ra) ranged from 0.00 to 0.36. For TC&SBP, TC&DBP, TG&SBP and TGs&DBP, both the Rph and Ra declined with age, and the Ra difference between the young group and the older adult group is statistically significant ( < .05). The unique environmental correlation (Re) of each pair did not follow any pattern with age and remained relatively stable with age. In summary, we observed that the heritability of blood pressure was affected by age. Moreover, blood pressure and serum lipids shared common genetic backgrounds, and age had an impact on the phenotypic correlation and genetic correlations.
Maternal and Neonatal Outcomes of Twin Pregnant Women With Anemia.
Lin N, Shen P, Hu H … +4 more , Song W, Hu Y, Dai Y, Zhou YH
Twin Res Hum Genet · 2023 Aug · PMID 37650223 · Publisher ↗
The aim of this study was to investigate the prevalence of anemia in twin pregnancies and the influence of anemia on maternal and neonatal outcomes. This retrospective study included twin pregnant women who delivered in...
The aim of this study was to investigate the prevalence of anemia in twin pregnancies and the influence of anemia on maternal and neonatal outcomes. This retrospective study included twin pregnant women who delivered in a tertiary hospital in China from January 2018 to December 2018. Patients were divided by WHO criteria (hemoglobin <11.0 g/dL): the anemic and nonanemic groups. Patients with anemia were further classified as recovered or unrecovered subgroup after oral iron therapy. Maternal and neonatal outcomes in women carrying twins were compared using Student's test and the chi-squared test or the Fisher exact test. Univariable and multivariable logistic regression models were used to determine the association of maternal and neonatal characteristics with anemia. Linear regression analysis was used to estimate mean birth weight and gestational week. The prevalence of anemia was 42.6% (182/427) in twin pregnancies. The anemic group had higher rates of low 1-minute Apgar score (4.4% vs. 1.8%, = .028), perinatal death (1.9% vs. 0.2%, = .012) and neonatal intensive care unit (NICU) admission (27.2% vs. 20.2%, = .017; adjusted , 1.478; 95% CI [1.07, 2.044]). The recovered subgroup had lower NICU admission rate (13.5% vs. 30.3%, = .006; , 0.388; 95% CI [0.186, 0.809]), higher gestational week and birth weight (β, 0.954 week; 95% CI [0.114, 1.794] and β, 171.01 g; 95% CI [9.894, 332.126] respectively). The prevalence of anemia in twin gestation is high. Anemia is associated with adverse neonatal outcomes, and correction of anemia significantly improved the pregnancy outcomes.
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