Twin Research and Human Genetics最新文献

This study examines the changes over time of the twinning rate and infant and child mortality across 17 rural villages in the province of Zaragoza (Spain) over a span of 200 years. The aim is to understand how the twinning rate evolved in conjunction with the processes of economic and social modernization, as well as the demographic transition. During the period analyzed, the twinning rate increased by 10%, rising from 1.26 per 1000 births in the second half of the 18th century to 1.38 per 1000 births in the first half of the 20th century. This rate varied due to hereditary issues, biological factors such as the mother's age and parity, and socioeconomic features like family occupation and the mother's education level. In terms of child mortality, twins historically faced a significantly higher mortality rate. However, they benefited greatly from the mortality transition, at least in absolute numbers. While nearly 60% of twins did not survive beyond 5 years of age in earlier periods, the mortality rate for twins decreased to 40% by the first half of the 20th century. The excess mortality was particularly severe for girls, driven by a widespread preference for sons, which led to higher mortality rates for girls in the first 5 years of life, especially in the earliest months. These findings help us understand the improvements in uterine and childhood survival rates for contemporary twins, which can be attributed to the socioeconomic and medical advancements of the 20th century.

Twins lag behind singletons in their early psychomotor development, but little is known about how chorionicity affects this difference. We compared early psychomotor development in singletons, monochorionic (MC) twins and dichorionic (DC) twins. Our longitudinal data from the Japan Environment and Children's Study (JECS; see Appendix) included 98,042 singletons, 577 MC twins and 1051 DC twins representing the general Japanese population. Chorionicity was evaluated by ultrasound images and complemented by postnatal pathological examinations. Five domains of psychomotor development were evaluated at 6 time points from 6 months to 3 years of age using the Ages and Stages Questionnaires (ASQ-3). The data were analyzed using linear regression models. Twins lagged behind singletons in all areas of psychomotor development during infancy. This gap decreased over time but was still noticeable at 3 years of age. More than half of this difference was attributed to twins having lower birth weight and being born earlier in gestation. MC twins showed slightly delayed development compared to DC twins, but this difference was minor compared to the overall gap between twins and singletons. Twins delay singletons in their early psychomotor development, and this delay is not specific to MC twinning.

Studies concerning twins with a sociological focus are scarce in Hungary as well as international research, although the number of twin births has increased dramatically worldwide. The raising and education of twins are tasks demanding special attention from both the family and institutions. In our study we examine these aspects, looking back from adulthood, using the narrow scope of the available data from research based on the 'Hungarostudy 2021' database (N total: 7000; n twins: 106). Our results, corresponding to the hypotheses of educational sociology, demonstrate how the relationships between family size and school career and increasing number of siblings reduces the chances of high educational attainment. A regression analysis confirmed that both the number of siblings and a later position in the birth order reduces the chance of obtaining a higher education. For the second child in a family, the chance of earning a university degree is reduced to to 0.743. The role of a large family concerning higher education showed a stronger relationship in the case of twins compared to nontwins. For twins, the sibling pattern has a decisive effect in educational attainment. Twins themselves have a 1.449 times higher chance of obtaining a higher education compared to nontwins (p = 0.101), and fraternal twins have half (0.517) the chance of obtaining a higher education compared to identical twins; but both results are not significant (p = 0.156).

Social support is often considered an environmental factor affecting health, especially in aging populations. However, its genetic underpinnings suggest a more complex origin. This study investigates the heritability of social support through applying a threshold model on data of a large adult sample of twins (N = 8019) from the Netherlands Twin Register, collected between 2009 and 2011. The study employed the Duke - UNC Functional Social Support Questionnaire to assess social support quality. Our analysis revealed genetic contributions to social support, with heritability estimated at 37%, without a contribution of shared environment and no differences between men and women in heritability. The study's results underscore the complexity of social support as a trait influenced by genetic and environmental factors, challenging the notion that it is solely an environmental construct.

Voice production can be influenced by interindividual variations related to genetic, physiological, behavioral, and several environmental factors. Here we examined the effect of zygosity on speaking fundamental frequency (F0) statistical descriptors. Our aims were: (1) to determine whether the genetic similarity between monozygotic (MZ) and dizygotic (DZ) twins affects F0 characteristics, and (2) to quantify the contribution of genetic factors to these characteristics. The study involved 79 same-sex twin pairs of Brazilian Portuguese speakers, comprising 65 MZ and 14 DZ twins, aged 18 to 66 years (31.7 ± 11.6 years), with 21 male and 58 female pairs. Participants were recorded while uttering a greeting phrase and the Brazilian Portuguese version of the 'Happy Birthday to You' song. Speech segments were analyzed using Praat free software, and F0 measures were automatically extracted in both Hertz and semitone scales. Statistical descriptors, including centrality, dispersion, and extreme values of F0 were examined, and the ACE model (i.e., total genetic effects, A; shared environmental influences, C; and nonshared environmental influences, E) was employed to estimate the additive effect;ts of monozygosity. As anticipated, we observed a zygosity effect on several F0 parameters, with more similarity between MZ twins compared to DZ twins. We discuss the genetic influences on F0 parameters and the absence of a monozygosity effect in two of them. Additionally, we briefly address potential biases associated with the selected measurement scale for statistical modeling. Finally, we explore the influence of genetic factors on F0 patterns, as well as environmental, life history and linguistic factors, particularly concerning F0 variation in speech.

Although the relationship between gaming addiction (GA) and attention deficit hyperactivity disorder (ADHD) is well established, the causal mechanism of this relationship remains ambiguous. We aimed to investigate whether common genetic and/or environmental factors explain the GA-ADHD relationship. We recruited 1413 South Korean adult twins (837 monozygotic [MZ], 326 same-sex dizygotic [DZ], and 250 opposite-sex DZ twins; mean age = 23.1 ± 2.8 years) who completed an online survey on GA and related traits. Correlational analysis and bivariate model-fitting analysis were conducted. Phenotypic correlation between GA and ADHD in the present sample was 0.55 (95% CI [0.51, 0.59]). Bivariate model-fitting analysis revealed that genetic variances were 69% (95% CI [64%, 73%]) and 68% (95% CI [63%, 72%]) for ADHD and GA respectively. The remaining variances (ADHD: 31%; GA: 32%) were associated with nonshared environmental variances, including measurement error. Genetic and nonshared environmental correlations between ADHD and GA were 0.68 (95% CI [0.62, 0.74]) and 0.22 (95% CI [0.13, 0.30]) respectively, which indicates that shared genes can explain 82% of the phenotypic correlation between ADHD and GA. Our study demonstrated that the ADHD-GA association was largely due to shared genetic vulnerability.

A tribute to the life and career of Dr Milton Diamond, a leading figure in twin studies of transsexuality and gender identity, is presented. Dr Diamond is famous for revealing the truth about the unsuccessful effort to change a monozygotic male Canadian twin into a female, following accidental ablation of his penis during circumcision. A short summary of recent twin research on human sexuality and transsexuality, focused on Dr Diamond's contributions, is then presented. The tribute and overview are followed by research reviews involving the loss of a twin brother; oxytocin adminstration during twin delivery; models of monochorionic twinning; and twins' brain responses to watching films. The final section of this article covers topics of human interest, including the passing of the world's oldest conjoined twins; twins discordant for child abuse; twins married to twins; the delivery of a rare quadruplet set; questions of coincidence; and reared-apart twin valedictorians.

Placental vascular anastomoses are traditionally thought to exist exclusively in monochorionic pregnancies. However, they have been reported in dichorionic twin pregnancies as well. In turn, twin to twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) have also been noted to impact some of these gestations. Through discussion of one such case at our institution along with a review of the available literature, we review the proposed pathophysiology of placental vascular anastamoses in dichorionic twin gestations, and aim to raise awareness of the possibility of associated pathologies in dichorionic gestations. This is an emerging area of literature that will require future study to guide prenatal surveillance and mitigate morbidity.