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Prenatal Diagnosis Apr 2008The aim of this study was to evaluate the effect of selective feticide (SF) compared to expectant management (EM) on perinatal outcome in dichorionic and monochorionic... (Review)
Review
The aim of this study was to evaluate the effect of selective feticide (SF) compared to expectant management (EM) on perinatal outcome in dichorionic and monochorionic twins discordant for anencephaly. For this purpose, we conducted a systematic review of literature and added ten unpublished cases. As a result, we found that in dichorionic twins, mean gestational age (GA) at birth in the SF group was 38.0 weeks versus 34.9 weeks (P = 0.0002). Mean birth weight was 2922 g in the SF group versus 2474 g (P = 0.03). In monochorionic twins, mean GA at birth was 35.2 weeks versus 32.7 weeks (P = 0.1). Mean birth weight was 2711 g versus 1667 g (P = 0.0001). We conclude that while SF does not reduce perinatal mortality, it does result in significantly longer gestations and higher birth weight, and appears to be the management of choice in dichorionic twins discordant for anencephaly. In monochorionic twins, SF also increases birth weight, but in view of the complexity of this group, no clear recommendations can be made.
Topics: Anencephaly; Diseases in Twins; Female; Humans; Pregnancy; Pregnancy Outcome; Pregnancy Reduction, Multifetal; Pregnancy, Multiple; Prenatal Care; Twins, Dizygotic; Twins, Monozygotic
PubMed: 18302309
DOI: 10.1002/pd.1967 -
JAMA Network Open Aug 2022Although infancy is the most rapid period of postnatal growth and development, factors associated with variation in infant traits are not well understood. (Meta-Analysis)
Meta-Analysis
IMPORTANCE
Although infancy is the most rapid period of postnatal growth and development, factors associated with variation in infant traits are not well understood.
OBJECTIVE
To synthesize the large twin study literature partitioning phenotypic variance in psychological traits and developmental milestones in infancy into estimates of heritability and shared and nonshared environment.
DATA SOURCES
PubMed, PsycINFO, and references of included publications were searched up to February 11, 2021.
STUDY SELECTION
Peer-reviewed publications using the classical twin design to study psychological traits and developmental milestones from birth to 2 years old were included.
DATA EXTRACTION AND SYNTHESIS
Data were extracted in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and categorized using the International Classification of Functioning, Disability and Health: Children and Youth Version. Data were pooled in 3-level random effects models, incorporating within-cohort variance in outcome measurement and between-cohort variance. Data were analyzed from March 2021 through September 2021.
MAIN OUTCOMES AND MEASURES
The primary outcomes were monozygotic and dizygotic twin correlations. These were used to calculate genetic and shared and nonshared environment estimates.
RESULTS
Among 139 publications that were systematically retrieved, data were available on 79 044 twin pairs (31 053 monozygotic and 47 991 dizygotic pairs), 52 independent samples, and 21 countries. Meta-analyses were conducted on psychological traits and developmental milestones from 106 publications organized into 10 categories of functioning, disability, and health. Moderate to high genetic estimates for 8 categories were found, the highest of which was psychomotor functions (pooled h2, 0.59; 95% CI, 0.25-0.79; P < .001). Several categories of traits had substantial shared environment estimates, the highest being mental functions of language (pooled c2, 0.59; 95% CI, 0.24-0.86; P = .001). All examined categories of traits had moderate or high nonshared environment estimates, the highest of which were emotional functions (pooled e2, 0.42; 95% CI, 0.33-0.50; P < .001) and family relationships (pooled e2, 0.42; 95% CI, 0.30-0.55; P < .001).
CONCLUSIONS AND RELEVANCE
These findings may be an important source of information to guide future gene discovery research, public perspectives on nature and nurture, and clinical insights into the degree to which family history and environments may estimate major domains of infant functioning, disability, and health in psychological traits and developmental milestones.
Topics: Adolescent; Child; Cohort Studies; Forecasting; Humans; Infant; Phenotype; Twins, Dizygotic
PubMed: 35994288
DOI: 10.1001/jamanetworkopen.2022.27887 -
Genetic and epigenetic influences of twins on the pathogenesis of craniosynostosis: a meta-analysis.Plastic and Reconstructive Surgery Apr 2012The pathoetiology of craniosynostosis is not well understood. It likely results from a combination of genetic and epigenetic phenomena, such as intrauterine constraint... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The pathoetiology of craniosynostosis is not well understood. It likely results from a combination of genetic and epigenetic phenomena, such as intrauterine constraint from multiple gestations. Information on craniosynostosis in twins is limited to case reports and series. The authors conducted a systematic review and meta-analysis of the literature to elucidate the genetic and nongenetic influences of twins on the pathogenesis of craniosynostosis.
METHODS
PubMed and Ovid databases were reviewed for the key terms "craniosynostosis and twins." Data analyzed included demographical information, incidence rates, concordance, and phenotypic variability. Risk factors for craniosynostosis, concordance, and phenotypic variability were assessed by univariate and multivariate analyses. A case series was presented.
RESULTS
Data were extracted from 34 journal articles, including the authors' five patients, and representing a total of 199 twins with craniosynostosis. Twinning was 2.62 times greater in patients with craniosynostosis (6.29 percent) compared with unaffected controls (2.4 percent; p < 0.0001). Boys were affected more than girls (65.30 versus 34.70 percent, respectively; p < 0.0001). Monozygotic concordance rates were greater than dizygotic (60.90 versus 5.30 percent, respectively; p < 0.0001) but were not 100 percent. Phenotypic variability was present in 62 percent of monozygotic twin sets (p < 0.05).
CONCLUSIONS
Increased concordance rates among monozygotic compared with dizygotic twins confirm the genetic role of twins on craniosynostosis. Evidence to support the epigenetic influence of twinning on the pathogenesis of craniosynostosis includes the elevated incidence of twins among a craniosynostotic population compared with unaffected twins in the general population and male gender predominance, as well as monozygotic phenotypic variability and discordance.
CLINICAL QUESTION/LEVEL OF EVIDENCE
Risk, IV.
Topics: Craniosynostoses; Diseases in Twins; Epigenesis, Genetic; Female; Humans; Infant; Male; Twins, Dizygotic; Twins, Monozygotic
PubMed: 22456364
DOI: 10.1097/PRS.0b013e31824422a8 -
Ultrasound in Obstetrics & Gynecology :... Feb 2019To quantify the rate of perinatal mortality in monochorionic monoamniotic (MCMA) twin pregnancies, according to gestational age, and to ascertain the incidence of... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To quantify the rate of perinatal mortality in monochorionic monoamniotic (MCMA) twin pregnancies, according to gestational age, and to ascertain the incidence of mortality in pregnancies managed as inpatients compared with those managed as outpatients.
METHODS
MEDLINE, EMBASE and CINAHL databases were searched for studies on monoamniotic twin pregnancy. The primary outcomes explored were the incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death (PND) in MCMA twins at different gestational-age windows (24-30, 31-32, 33-34, 35-36 and ≥ 37 weeks of gestation). The secondary outcomes were the incidence of IUD, NND and PND in MCMA twins according to the type of fetal monitoring (inpatient vs outpatient), and the incidence of delivery ahead of schedule. Random-effects model meta-analyses were used to analyze the data.
RESULTS
Twenty-five studies (1628 non-anomalous twins reaching 24 weeks of gestation) were included. Single and double intrauterine deaths occurred in 2.5% (95% CI, 1.8-3.3%) and 3.8% (95% CI, 2.5-5.3%) of cases, respectively. IUD occurred in 4.3% (95% CI, 2.8-6.2%) of twins at 24-30 weeks, in 1.0% (95% CI, 0.6-1.7%) at 31-32 weeks and in 2.2% (95% CI, 0.9-3.9%) at 33-34 weeks of gestation, while there was no case of IUD, either single or double, from 35 weeks of gestation. In MCMA twin pregnancies managed mainly as inpatients, the incidence of IUD was 3.0% (95% CI, 1.4-5.2%), while the corresponding figure for those managed mainly as outpatients was 7.4% (95% CI, 4.4-11.1%). Finally, 37.8% (95% CI, 28.0-48.2%) of MCMA pregnancies were delivered before the scheduled time, due mainly to spontaneous preterm labor or abnormal cardiotocographic findings.
CONCLUSIONS
MCMA twins are at high risk of perinatal loss during the third trimester of pregnancy, with the large majority of such losses occurring as apparently unexpected events. Inpatient management seems to be associated with a lower rate of mortality, although further studies are needed in order to establish the appropriate type and timing of prenatal assessment in these pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.
Topics: Female; Gestational Age; Humans; Infant, Newborn; Perinatal Care; Perinatal Mortality; Pregnancy; Pregnancy, Twin; Premature Birth; Retrospective Studies; Time Factors; Twins, Monozygotic
PubMed: 30125418
DOI: 10.1002/uog.20100 -
Journal of Clinical Medicine Sep 2023Coronary artery disease (CAD) is multifactorial and strongly affected by genetic, epigenetic and environmental factors. Several studies have reported development of... (Review)
Review
Coronary artery disease (CAD) is multifactorial and strongly affected by genetic, epigenetic and environmental factors. Several studies have reported development of concomitant CAD in identical twins. We report a case in which a pair of Caucasian male monozygotic twins presented almost concomitantly with acute coronary syndrome (ACS) and had concordant coronary anatomy and identical site of occlusion. We performed a systematic literature review of PubMed, Web Of Science and Scopus databases from inception until 28 February 2023 of case reports/case series reporting the concomitant development of CAD in monozygotic twins. We found 25 eligible case reports with a total of 31 monozygotic twin pairs (including the case from our center) suffering from CAD and presenting (most of them simultaneously) with ACS (mean age of presentation: 45 ± 12 years, males: 81%). Coronary angiograms demonstrated lesion and anatomy concordance in 77% and 79% of the twin pairs, respectively. Screening for disease-related genetic mutations was performed in six twin pairs leading to the identification of five CAD-related genetic polymorphisms. This is the first systematic literature review of studies reporting identical twin pairs suffering from CAD. In summary, there is high concordance of coronary anatomy and clinical presentation between monozygotic twins. Future monozygotic twin studies-unbiased by age effects-can provide insights into CAD heritability being able to disentangle the traditional dyad of genetic and environmental factors and investigate the within-pair epigenetic drift.
PubMed: 37685809
DOI: 10.3390/jcm12175742 -
The Cochrane Database of Systematic... Apr 2015Monoamniotic twin pregnancies are formed when a single egg is fertilised and the resulting inner cell mass splits to form twins sharing the same amniotic sac. This... (Review)
Review
BACKGROUND
Monoamniotic twin pregnancies are formed when a single egg is fertilised and the resulting inner cell mass splits to form twins sharing the same amniotic sac. This condition is rare and affects about one in 10,000 pregnancies overall. Monoamniotic twin pregnancies are susceptible to complications including cord entanglement, increased congenital anomalies, intrauterine growth restriction, twin-to-twin transfusion syndrome and increased perinatal mortality. All twin pregnancies also carry additional maternal risks including pre-eclampsia, anaemia, antepartum haemorrhage, postpartum haemorrhage and operative delivery.The optimal timing for the delivery of monoamniotic twins is not known. The options include 'planned early delivery' between 32 and 34 weeks, or alternatively awaiting spontaneous labour at least up until the usual time of planned delivery for other monochorionic twins (approximately 36 to 38 weeks' gestation), unless there is a specific indication for earlier delivery.
OBJECTIVES
To assess whether routine early delivery in monoamniotic twin pregnancies improves fetal, neonatal or maternal outcomes compared with 'expectant management'. Expectant management means awaiting spontaneous labour at least up until the usual time of planned delivery for other monochorionic twins (approximately 36 to 38 weeks' gestation in many centres), unless a specific indication for delivery occurs in the meantime, e.g. for non-reassuring antenatal testing.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2015).
SELECTION CRITERIA
Published and unpublished randomised controlled trials (including cluster-randomised trials) comparing outcomes for women and infants who were randomised to planned early delivery of a monoamniotic twin pregnancy with outcomes for women and infants who were randomised to either planned term delivery or expectant management. However, we did not identify any trials for inclusion in this review.Quasi-randomised controlled trials, trials published in abstract form only, and trials using a cross-over design are not eligible for inclusion in this review.
DATA COLLECTION AND ANALYSIS
No trials were identified by the search strategy.
MAIN RESULTS
No trials were identified by the search strategy.
AUTHORS' CONCLUSIONS
Monoamniotic twins are rare, and there is insufficient randomised controlled evidence on which to draw strong conclusions about the best management. In their absence, we can refer to historical case series and expert consensus. Management plans should take into consideration the availability of high-quality neonatal care if early delivery is chosen. Women and their families should be involved in the decision making about these high-risk pregnancies.Ongoing, multicentre audits of maternal and perinatal outcomes for monoamniotic twins are needed in order to inform families and clinicians about up-to-date perinatal outcomes with contemporary obstetric practice. Research should consider the social and economic implications of planned interventions, as well as the perinatal outcomes.
Topics: Delivery, Obstetric; Female; Humans; Pregnancy; Pregnancy, Twin; Twins, Monozygotic; Watchful Waiting
PubMed: 25906204
DOI: 10.1002/14651858.CD008820.pub2 -
Wiener Klinische Wochenschrift 2007Convergent evidence from a multitude of research designs (adoption, family, genomescan, geographical, immigrant, molecular genetic, surname, and twin studies of suicide)... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Convergent evidence from a multitude of research designs (adoption, family, genomescan, geographical, immigrant, molecular genetic, surname, and twin studies of suicide) suggests genetic contributions to suicide risk. The present account provides a comprehensive and up-to-date review of the twin studies on this topic.
METHODS
A total of 32 studies (19 case reports, 5 twin register-based studies, 4 population-based epidemiological studies, 4 studies of surviving co-twins) located through extensive literature search strategies are summarized and discussed here. This literature corpus was published between 1812 and 2006 in six languages and reports data from 13 countries.
RESULTS
A meta-analysis of all register-based studies and all case reports aggregated shows that concordance for completed suicide is significantly more frequent among monozygotic than dizygotic twin pairs. The results of co-twin studies rule out exclusively psychosocially based explanations of this pattern. Population-based epidemiological studies demonstrate a significant contribution of additive genetic factors (heritability estimates: 30-55%) to the broader phenotype of suicidal behavior (suicide thoughts, plans and attempts) that largely overlaps for different types of suicidal behavior and is largely independent of the inheritance of psychiatric disorders. Nonshared environmental effects (i.e. personal experiences) also contribute substantially to the risk of suicidal behavior, whereas effects of shared (family) environment do not.
CONCLUSIONS
The totality of evidence from twin studies of suicide strongly suggests genetic contributions to liability for suicidal behavior. To further research progress in this area, an extensive discussion of design limitations, shortcomings of the literature and further points is provided, including sources of bias, gaps in the literature, errors in previous reviews, age and sex effects and twin-singleton differences in suicide risk, and notes from a history-of-science view.
Topics: Cause of Death; Diseases in Twins; Female; Genetic Predisposition to Disease; Humans; Male; Mental Disorders; Phenotype; Population Surveillance; Risk Factors; Social Environment; Suicide; Suicide, Attempted; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic
PubMed: 17721766
DOI: 10.1007/s00508-007-0823-2 -
Journal of Dentistry Aug 2023This review aimed to assess the agreement of dental caries experience between monozygotic (MZ) and dizygotic (DZ) twins. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
This review aimed to assess the agreement of dental caries experience between monozygotic (MZ) and dizygotic (DZ) twins.
DATA RESOURCES
This systematic review was performed by reviewers in the databases Embase, MEDLINE-PubMed, Scopus, Web of Science and manual searches and gray literature Google Scholar® and Opengray. Observational studies that evaluated dental caries in twins were included. The risk of bias was analyzed using the Joanna Briggs checklist. Meta-analyses were performed to assess the pooled Odds Ratio to estimate the agreement values of dental caries experience and DMF index between pairs of twins (p < 0.05). To assess the certainty of evidence, the GRADE scale was used.
STUDY SELECTION
2533 studies were identified, of which 19 were included in the qualitative analysis, six in the quantitative synthesis, with two meta-analyses being carried out. Association between genetics and the development of the disease was observed in most studies. In the risk of bias analysis, 47.4% had moderate risk. Higher agreement of dental caries experience was observed in MZ twins than DZ in both dentitions (OR: 5.94; 95% CI: 2.00-17.57). However, there was no difference between the MZ and DZ twin groups in the analysis comparing DMF index agreement (OR: 2.86; 95%CI: 0.25-32.79). The certainty of evidence was considered low and very low for all studies included in meta-analyses.
CONCLUSION
With very low certainty of the evidence, the genetic factor seems to influence the agreement of the caries experience.
CLINICAL RELEVANCE
Understanding the genetic influence on the disease has the potential to contribute to the development of studies that may use biotechnologies for prevention and treatment as well as guide future research involving gene therapies aiming to prevent the occurrence of dental caries.
Topics: Humans; Dental Caries; Bias; DMF Index; Odds Ratio
PubMed: 37339689
DOI: 10.1016/j.jdent.2023.104586 -
Birth Defects Research. Part A,... Mar 2012Isolated esophageal atresia (EA) is a rare congenital malformation whose etiology remains largely unknown. Nine twin pairs with EA were identified from our clinical... (Review)
Review
BACKGROUND
Isolated esophageal atresia (EA) is a rare congenital malformation whose etiology remains largely unknown. Nine twin pairs with EA were identified from our clinical service, prompting the performance of a systematic review of the literature and the first reported twin study of isolated EA.
METHODS
A total of 330 twin pairs with EA were identified from the literature. The zygosity, concordance, and malformation (isolated vs. nonisolated) status of all 339 twin pairs were evaluated. A total of 72 twin pairs (4 of 9 / 68 of 330) fulfilled the criteria for inclusion in a classic twin study of isolated EA.
RESULTS
The pairwise concordance rates were 50% (95% confidence interval [CI], 34-66%) for monozygous (MZ) twin pairs and 26% (95% CI, 15-42%) for dizygous (DZ) twin pairs (p = 0.033). The probandwise concordance rates were 67% (95% CI, 53-78%) for MZ twin pairs and 42% (95% CI, 29-56%) for DZ twin pairs (p = 0.011). The MZ/DZ ratios were 1.9 for pairwise analysis and 1.6 for probandwise analysis. The familial risk ratios for MZ and DZ twin pairs were 1700 and 900, respectively.
CONCLUSION
The observation of higher concordance rates for MZ compared to DZ twin pairs indicates that genetic factors contribute to isolated EA.
Topics: Diseases in Twins; Esophageal Atresia; Female; Genetic Predisposition to Disease; Humans; Male; Twins, Dizygotic; Twins, Monozygotic
PubMed: 22287212
DOI: 10.1002/bdra.22879 -
Archives of Oral Biology Aug 2023To determine the association between genetic factors and molar-incisor hypomineralisation (MIH) and/or hypomineralised second primary molars by means of a systematic... (Review)
Review
OBJECTIVE
To determine the association between genetic factors and molar-incisor hypomineralisation (MIH) and/or hypomineralised second primary molars by means of a systematic review.
DESIGN
A search was performed in Medline-PubMed, Scopus, Embase and Web of Science databases; manual search and search in gray literature were also performed. Selection of articles was performed independently by two researchers. A third examiner was involved in cases of disagreement. Data extraction was performed using an Excel® spreadsheet and independent analysis was performed for each outcome.
RESULTS
Sixteen studies were included. There was an association between MIH and genetic variants related to amelogenesis, immune response, xenobiotic detoxification and other genes. Moreover, interactions between amelogenesis and immune response genes, and SNPs in the aquaporin gene and vitamin D receptors were associated with MIH. Greater agreement of MIH was found in pairs of monozygotic twins than dizygotic twins. The heritability of MIH was 20 %. Hypomineralised second primary molars was associated with SNPs in the hypoxia-related HIF-1 gene and methylation in genes related to amelogenesis.
CONCLUSION
With very low or low certainty of evidence, an association was observed between MIH and SNPs in genes associated with amelogenesis, immune response, xenobiotic detox and ion transport. Interactions between genes related to amelogenesis and immune response as well as aquaporin genes were associated to MIH. With very low certainty of evidence, hypomineralised second primary molars was associated to a hypoxia-related gene and to methylation in genes related to amelogenesis. Moreover, higher agreement of MIH in pairs of monozygotic twins than dizygotic twins was observed.
Topics: Humans; Dental Enamel Hypoplasia; Molar Hypomineralization; Xenobiotics; Amelogenesis; Molar; Prevalence
PubMed: 37210809
DOI: 10.1016/j.archoralbio.2023.105716