Twin Research and Human Genetics最新文献

The Serbian Twin Advanced Registry (STAR), established in 2014, is a multigenerational resource for studying genetic, environmental, and epigenetic influences on behavior and development. STAR currently includes more than 9000 participants, extending the classical twin design to parents and siblings and enabling fine-grained modeling of genetic inheritance, cultural transmission, and shared environments. Methodological innovations include experimental procedures, virtual reality paradigms, and longitudinal, multi-informant assessments from childhood to adulthood, combined with molecular data collection. Published findings highlight heritable structures in executive functions, personality, and psychopathology, alongside environmentally shaped differences in behaviors such as aggression. Epigenetic studies have demonstrated associations between COMT promoter methylation and impulsivity-related traits, while ongoing genomewide analyses aim to identify environmentally mediated methylation variability. By integrating advanced methodologies with open science practices, STAR provides a sustainable platform for behavioral genetics in Serbia and contributes to international research on adaptation and psychopathology across the lifespan.

This study evaluated the growth trajectories of twins from birth to school age, focusing on weight and height z scores of children born in São Paulo. The longitudinal study comprised 188 healthy twins (M = 9.13 years; SD = 2.16). Weight data were obtained from birth records and reassessed at school age, and height at school age. Singleton birth weights and standard growth curves were used as reference points. Overall, the proportion of children with z scores below the median decreased significantly, from 98.3% at birth to 31.4% at school age. At birth, the dispersion of z-scores below the median was significantly greater among monochorionic compared to dichorionic twins (2.051 vs. 1.701), but this difference was no longer observed at school age (1.861 vs. 0.976). In total, 68.8% of the twins showed improved weight development, with no cases of deterioration. While monozygotic (MZ) and dizygotic (DZ) twin pairs exhibited comparable intertwin birth-weight differences, by school age MZ pairs exhibited more similar weights, whereas DZ pairs showed significantly greater weight discrepancies. For height at school age, mean height z scores were within the expected range for singletons. No significant differences were observed between monochorionic and dichorionic twins, whereas MZ pairs showed smaller within-pair height differences than DZ pairs. These findings suggest that although chorionicity plays an important role during the perinatal period - particularly due to the lower birth weights observed among monochorionic twins - its influence diminishes over time. By school age, weight and height differences are primarily determined by zygosity.

This article presents an overview of the life histories of reared-apart twins from the Philippines. One twin always knew he was a twin, but for the other twin the discovery at age 15 came as a shock. This essay is followed by summaries of recent twin research of interest. Topics include twin discordance for multisystem inflammatory syndrome, in vitro fertilization (IVF) twins and possible associations with impaired hearing, the writings of monozygotic (MZ) twins, and an update on MZ twins with Feingold syndrome whom I have covered in a previous issue of this journal. This essay concludes with several twin-related human interest stories, namely conjoined twin girls from Sri Lanka, conjoined twin boys from Papua, New Guinea, recent information concerning conjoined twins Abby and Brittany Hensel, a twin sentenced for criminal activities, and accurate identification of an identical twin culprit by DNA sequencing.

The Painel USP de Gêmeos (University of São Paulo Twin Panel) is, based at the Instituto de Psicologia da Universidade de São Paulo. It was formally established in 2017 to advance research on fundamental psychological processes through twin study designs. Our relatively new registry comprises a volunteer sample of 8839 twin individuals, 70% of whom live in Brazil's Southeast, the region with the highest twinning birth rate (10.64‰) of the country, within a national population of 213 million. Our collaborative research group has expanded to include partners from psychology, dentistry, and medicine at USP, as well as other Brazilian institutions, such as the Universidade Federal do Rio Grande do Norte, Universidade Federal da Bahia, and Universidade Federal do Espírito Santo. We are advancing biobehavioral research in Brazil through innovative methodologies, interdisciplinary collaboration, and international partnerships. All twin participants contribute to multiple studies associated with four datasets employing the same hierarchical identification system for participants and families: the Biorepository, the Physiological and Physical Repository, the Behavioral Repository, and Fonoteca Cesar Ades (FOCA). Future directions include expanding our twin registry across the five regions of Brazil, our research partnerships, promoting genetic literacy, and fostering public engagement.

A simple application of urn models is useful in spelling out the way in which, in abstraction, if the parents are distributed in Hardy-Weinberg form, that form is reproduced in offspring with nonrandom mating. A measure of divergence from random mating is proposed and illustrated by numerical examples. The scope of urn models of stochastic processes in population genetics theory is set out.

Obesity represents a major global public health concern. Body fat percentage (BF%) is a key indicator for assessing adiposity and provides a more precise estimation of obesity-related health risks compared to the traditional body mass index (BMI). Accumulating evidence suggests that BF% is influenced by both genetic and environmental factors. However, most genetic studies on BF% have been conducted in European and American population, with limited data available from Chinese cohorts. To address this gap, a classical twin study was conducted using data from the Qingdao Twin Registry in China to estimate the heritability of BF% adjusted for age, sex, and BMI. This study included Han Chinese twins registered in the Qingdao Twin Registry. This study included 344 middle and old-aged Chinese twin pairs (217 monozygotic and 127 dizygotic). comprising 327 males and 361 females. The median age of participants was 50 (interquartile range [IQR]:12) years, with BF% of 27.6 (11.4) %. Model fitting indicated that the best-fitting model was AE model. The additive genetic effect (A) accounted for 54% (95% CI [44, 59) of the total variance, while unique environmental effect (E) contributed 46% (95% CI [37, 56]). In conclusion, this twin-based study provides robust evidence for a moderate genetic contribution (heritability = 54%) to BF% in a middle- and old-aged Qingdao population.

Attention deficit/hyperactivity disorder (ADHD) is associated with an increased risk of cardiovascular diseases (CVDs). However, whether this is a causal relation and how ADHD may predispose to a higher risk of CVD needs to be determined. We aimed to assess the causal association between ADHD and both coronary artery disease (CAD) and heart failure (HF), and to quantify the mediating effects of potential modifiable mediators. We conducted a two-step, two-sample Mendelian randomization (MR) study using SNPs as genetic instruments for exposure and potential mediators. Leveraging summary data on the latest genomewide association studies for ADHD, proposed mediators (i.e., metabolic factors, inflammatory factors, lifestyle behaviors, psychiatric disorders, and educational attainment), CAD and HF, we decomposed the total effect of ADHD on each outcome into direct and indirect effects through multiple mediators. Genetically predicted ADHD was associated with increased odds of CAD (OR 1.13; 95% CI [1.07, 1.19]), with educational attainment (EA) being the largest contributor (32.27% mediation, 95% CI [18.33%, 56.93%]). Body mass index (BMI), type 2 diabetes (T2D), EA, smoking initiation (SI), and depression jointly explained 83.59% (95% CI [63.95%, 101.49%]) of the association. Genetically predicted ADHD was associated with increased odds of HF (OR 1.11; 95% CI [1.05, 1.19]), with SI being the largest contributor (35.87% mediation, 95% CI [13.75%, 100.14%]). BMI, T2D, and SI jointly explained 82.39% (95% CI [45.90%, 131.60%]) of the association. The findings support a causal relationship between ADHD and both CAD and HF. Several modifiable risk factors substantially mediate these associations, suggesting potential targets for interventions aimed at reducing CVD risk in individuals with ADHD.

This position statement provides guidelines for health professionals who are considering online or direct-to-consumer genetic testing for their patients. It presents the major issues around online and direct-to-consumer (DTC) testing including how it is accessed, motivations for accessing testing and how to return these results. Online or DTC recommendations include: (1) DTC testing should only be done by individuals/consumers who are well informed, aware of the risks, benefits and limitations of testing, and able to consent for their DNA to be collected, analyzed and potentially stored. Where possible, individuals/consumers should also be aware of the alternative option of undertaking testing through healthcare professionals in a clinical context, and the benefits of this. (2) Decisions about having a child tested should be based on peer-reviewed, published evidence. Genomics testing for children should be within a clinical context where parents are informed, have access to clinical support and professional genetic counseling about this decision, as well as support for the range of results received. (3) Parents considering direct-to-consumer testing on their newborn are counselled, or given information, to encourage them to have standard government funded newborn bloodspot screening testing on their newborn. (4) When choosing an online genomic test, preference should be given to tests undertaken in accredited laboratories offering tests accredited with the Therapeutic Goods Administration. (5) Results obtained through methods other than direct analysis from a laboratory accredited to perform genomic testing to inform human health and wellbeing should be interpreted with caution. The HGSA recommends that such results must be confirmed in an accredited diagnostic laboratory prior to relying on them to inform options for treatment, surveillance or risk reduction, or before undertaking cascade testing in family members. (6) When individuals are concerned about their health, they should consult an appropriate healthcare professional to decide whether an online genomic test is appropriate and discuss how useful test results could be to make health-related decisions.

The Interplay of Genes and Environment across Multiple Studies (IGEMS) is a consortium of 21 twin studies from 5 countries (Australia, Denmark, Finland, Sweden, and United States) established to explore the nature of gene-environment interplay in cognitive, physical, and emotional health across the adult lifespan. The combined data from over 145,000 participants (aged 18 to 108 years at intake) has supported multiple research projects over the three phases of development since its inception in 2010. Phases 1 and 2 focused on launching and growing the consortium and supported important developments in data harmonization, analyses of data pooled across multiple studies, incorporation of linkages to national registries and conscription data, and integration of molecular genetic and classical twin designs. IGEMS Phase 3 focuses on developing appropriate infrastructure to maximize utilization of this large twin consortium for aging research.

A pair of dizygotic (DZ) twins discordant for Turner syndrome are discussed with reference to the biological origins of the condition and the effects of discordance on the twin relationship. There is little research on how having an atypical twin influences the life events and goals of the typical twin. Next, timely reviews of research on preventing premature twin birth, a twin gestation with hydatidiform mole, an update on Feingold syndrome twins discussed in a previous issue of this journal, and qualitative monozygotic twin difference studies are presented. The final portion of this article covers human interest stories of twins that are variously entertaining and enlightening. They include identical twins who celebrated their 100th birthday together, twins in famous families, celebration of the Yorùbá twins of Nigeria, identical artistic partners, and surgical separation of a rare, conjoined twin set.