WorldWideScience

Sample records for twin pairs aged

  1. Estimating Twin Pair Concordance for Age of Onset

    DEFF Research Database (Denmark)

    Scheike, Thomas H; Hjelmborg, Jacob B; Holst, Klaus K

    2015-01-01

    that they will develop the disease. The aim of this contribution is to show that the standard casewise concordance and standard prevalence estimators do not work in general for age-of-onset data. We show how one can in fact do something easy and simple even with censored data. The key is to take age into account when......Twin and family data provide a key source for evaluating inheritance of specific diseases. A standard analysis of such data typically involves the computation of prevalences and different concordance measures such as the casewise concordance, that is the probability that one twin has the disease...

  2. Age of Onset in Concordant Twins and Other Relative Pairs With Multiple Sclerosis

    OpenAIRE

    Sadovnick, A. Dessa; Yee, Irene M.; Guimond, Colleen; Reis, Jacques; Dyment, David A.; Ebers, George C.

    2009-01-01

    The ages of onset in multiple sclerosis cases span more than 7 decades. Data are presented for affected relative pairs from a Canadian population base of 30,000 multiple sclerosis index cases (1993?2008). The effects of genetic sharing, parent of origin, intergenerational versus collinear differences, and gender on the ages of onset were evaluated in the following concordant pairs: monozygotic twins (n?=?29), dizygotic twins (n?=?10), siblings (n?=?614), first cousins (n?=?405), half siblings...

  3. Genetic and environmental contributions to weight, height, and BMI from birth to 19 years of age: an international study of over 12,000 twin pairs.

    Directory of Open Access Journals (Sweden)

    Lise Dubois

    Full Text Available OBJECTIVE: To examine the genetic and environmental influences on variances in weight, height, and BMI, from birth through 19 years of age, in boys and girls from three continents. DESIGN AND SETTINGS: Cross-sectional twin study. Data obtained from a total of 23 twin birth-cohorts from four countries: Canada, Sweden, Denmark, and Australia. Participants were Monozygotic (MZ and dizygotic (DZ (same- and opposite-sex twin pairs with data available for both height and weight at a given age, from birth through 19 years of age. Approximately 24,036 children were included in the analyses. RESULTS: Heritability for body weight, height, and BMI was low at birth (between 6.4 and 8.7% for boys, and between 4.8 and 7.9% for girls but increased over time, accounting for close to half or more of the variance in body weight and BMI after 5 months of age in both sexes. Common environmental influences on all body measures were high at birth (between 74.1-85.9% in all measures for boys, and between 74.2 and 87.3% in all measures for girls and markedly reduced over time. For body height, the effect of the common environment remained significant for a longer period during early childhood (up through 12 years of age. Sex-limitation of genetic and shared environmental effects was observed. CONCLUSION: Genetics appear to play an increasingly important role in explaining the variation in weight, height, and BMI from early childhood to late adolescence, particularly in boys. Common environmental factors exert their strongest and most independent influence specifically in pre-adolescent years and more significantly in girls. These findings emphasize the need to target family and social environmental interventions in early childhood years, especially for females. As gene-environment correlation and interaction is likely, it is also necessary to identify the genetic variants that may predispose individuals to obesity.

  4. Personality, depression, and premorbid lifestyle in twin pairs discordant for Parkinson's disease

    Science.gov (United States)

    Heberlein, I.; Ludin, H.; Scholz, J.; Vieregge, P.

    1998-01-01

    Present personality traits (Freiburg personality inventory, FPI-R), depression (von Zerssen's depression scale), and self assessed state of health were evaluated in 15 twin pairs (six monozygotic and nine dizygotic; mean age 62.5 years) discordant for idiopathic Parkinson's disease and in 17 unrelated healthy control subjects. The twins had additional questionnaire based interviews on premorbid lifestyle.
For disability, twins with Parkinson's disease scored lower on FPI-R than controls in "achievement orientation" and "extraversion", higher in "inhibitedness", "somatic complaints", and "emotionality". They scored higher for depression and for state of health than unaffected twins and controls. For zygosity, monozygotic twins scored lower than dizygotic twins in "achievement orientation", "aggressiveness", and "strain". Monozygotic twins had less "achievement orientation" and "extraversion" and more "somatic complaints" than controls. Monozygotic twins had a lower within pair difference than dizygotic twins in "social orientation". During premorbid times the affected twin with later Parkinson's disease was estimated to have been "less often the leader" in the twin pair.
Although small in sample size, this twin study indicates a genetic impact for some personality features beyond the Parkinson's disease motor syndrome.

 PMID:9489545

  5. Functional and effective whole brain connectivity using magnetoencephalography to identify monozygotic twin pairs.

    Science.gov (United States)

    Demuru, M; Gouw, A A; Hillebrand, A; Stam, C J; van Dijk, B W; Scheltens, P; Tijms, B M; Konijnenberg, E; Ten Kate, M; den Braber, A; Smit, D J A; Boomsma, D I; Visser, P J

    2017-08-29

    Resting-state functional connectivity patterns are highly stable over time within subjects. This suggests that such 'functional fingerprints' may have strong genetic component. We investigated whether the functional (FC) or effective (EC) connectivity patterns of one monozygotic twin could be used to identify the co-twin among a larger sample and determined the overlap in functional fingerprints within monozygotic (MZ) twin pairs using resting state magnetoencephalography (MEG). We included 32 cognitively normal MZ twin pairs from the Netherlands Twin Register who participate in the EMIF-AD preclinAD study (average age 68 years). Combining EC information across multiple frequency bands we obtained an identification rate over 75%. Since MZ twin pairs are genetically identical these results suggest a high genetic contribution to MEG-based EC patterns, leading to large similarities in brain connectivity patterns between two individuals even after 60 years of life or more.

  6. Gut microbiomes of Malawian twin pairs discordant for kwashiorkor

    Science.gov (United States)

    Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin ...

  7. The 16th International Twin Congress: Highlights from Madrid/Twin Research: Twin Study of Partner Aggression; ABO Incompatibility in Dizygotic Twins; Growth Discordance in a Monoamniotic Twin Pair; Quick Note on Twin Implantation/In the Media: Long-Lost Twins Found; NASA Twin Experiment; Twin Brothers and the Las Vegas Attack; Retired Twin Airline Pilots; Twin Film Clips.

    Science.gov (United States)

    Segal, Nancy L

    2018-02-01

    Highlights from the 16th International Twin Congress, held in Madrid, Spain from November 16-18, 2017, are presented. The Twin Congress, formerly held every three years, now takes place biennially with a single-day meeting organized during the off years. This meeting is the largest gathering of scientific twin researchers, medical personnel, and representatives of multiple birth organizations in the world. This overview is followed by reviews of recent twin research and commentary concerning partner aggression, ABO incompatibility in dizygotic twins, growth discordance in a monoamniotic twin pair and twin implantation. The article closes with summaries of timely topics in the media, namely a father's finding of his long-lost twin children, early results from the NASA twin experiment, twin brothers at the center of the October 2017 Las Vegas attack, retired twin airline pilots, and clips from recent films with twin-based themes.

  8. Objective assessment of facial skin aging and the associated environmental factors in Japanese monozygotic twins

    OpenAIRE

    Ichibori, Ryoko; Fujiwara, Takashi; Tanigawa, Tomoko; Kanazawa, Shigeyuki; Shingaki, Kenta; Torii, Kosuke; Tomita, Koichi; Yano, Kenji; Sakai, Yasuo; Hosokawa, Ko

    2014-01-01

    Twin studies, especially those involving monozygotic (MZ) twins, facilitate the analysis of factors affecting skin aging while controlling for age, gender, and genetic susceptibility. The purpose of this study was to objectively assess various features of facial skin and analyze the effects of environmental factors on these features in MZ twins. At the Osaka Twin Research Center, 67 pairs of MZ twins underwent medical interviews and photographic assessments, using the VISIA® Complexion Analys...

  9. Secular trends in gestational age and birthweight in twins.

    Science.gov (United States)

    Gielen, M; van Beijsterveldt, C E M; Derom, C; Vlietinck, R; Nijhuis, J G; Zeegers, M P A; Boomsma, D I

    2010-09-01

    In recent decades, the overall rate of preterm births has increased. The aim of the present study was to examine whether this trend is also seen for multiple gestations. More specifically, we examined if there has been a decrease in gestational age for live born monozygotic (MZ) and dizygotic (DZ) twins and if there has been a simultaneous change in birthweight. The contributions of fertility treatments and Caesarean sections were taken into consideration. All analyses were carried out in two large European twin cohorts. Cross-sectional study of 6310 live born twin pairs, born between 1964-2007, from the Belgian East Flanders Prospective Twin Survey and 14,712 twin pairs, born between 1990-2006, from the Netherlands Twin Register. Multiple regression analyses were performed with gestational age as outcome variable, and multilevel analysis with birthweight as outcome variable. All analyses were performed with and without adjustment for zygosity, parity, maternal age, mode of conception and delivery and, for the analyses of birthweight, gestational age. Gestational age decreased in a linear fashion from 1964 to 2007 with a decrease of 0.25 days per year in a similar way for MZ and DZ twins. Changes in birthweight depended on gestational age: up to 32 weeks, birthweight decreased and after 32 weeks birthweight increased. The frequency of infertility treatment and Caesarean sections, primiparity and advanced maternal age increased over the years, but none of these factors influenced the secular trends in gestational age and birthweight. The decrease in gestational age and change in birthweight in twins are sources of concern, especially for very preterm twins, for whom birthweight decreased. For twins born after 32 weeks, an increase in birthweight was observed and this is very likely the explanation for the decrease in gestational age.

  10. The Concordance and Heritability of Type 2 Diabetes in 34,166 Twin Pairs From International Twin Registers

    DEFF Research Database (Denmark)

    Willemsen, G.; Ward, K. J.; Bell, C. G.

    2015-01-01

    studies worldwide need to pool their resources. The Discordant Twin (DISCOTWIN) consortium was established for this goal. Here, we describe the DISCOTWIN Consortium and present an analysis of type 2 diabetes (T2D) data in nearly 35,000 twin pairs. Seven twin cohorts from Europe (Denmark, Finland, Norway...... and medication use, fasting glucose and insulin measures, or medical records. The prevalence of T2D ranged from 2.6% to 12.3% across the cohorts depending on age, body mass index (BMI), and national diabetes prevalence. T2D discordance rate was lower for MZ (5.1%, range 2.9-11.2%) than for same-sex dizygotic (DZ......, the Netherlands, Spain, Sweden, and the United Kingdom) and one from Australia investigated the rate of discordance for T2D in same-sex twin pairs aged 45 years and older. Data were available for 34,166 same-sex twin pairs, of which 13,970 were MZ, with T2D diagnosis based on self-reported diagnosis...

  11. Twin photon pairs in a high-Q silicon microresonator

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Steven; Lu, Xiyuan [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Jiang, Wei C. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Lin, Qiang, E-mail: qiang.lin@rochester.edu [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627 (United States)

    2015-07-27

    We report the generation of high-purity twin photon pairs through cavity-enhanced non-degenerate four-wave mixing (FWM) in a high-Q silicon microdisk resonator. Twin photon pairs are created within the same cavity mode and are consequently expected to be identical in all degrees of freedom. The device is able to produce twin photons at telecommunication wavelengths with a pair generation rate as large as (3.96 ± 0.03) × 10{sup 5} pairs/s, within a narrow bandwidth of 0.72 GHz. A coincidence-to-accidental ratio of 660 ± 62 was measured, the highest value reported to date for twin photon pairs, at a pair generation rate of (2.47 ± 0.04) × 10{sup 4} pairs/s. Through careful engineering of the dispersion matching window, we have reduced the ratio of photons resulting from degenerate FWM to non-degenerate FWM to less than 0.15.

  12. Heritability of cortical thickness changes over time in twin pairs discordant for schizophrenia.

    Science.gov (United States)

    Hedman, Anna M; van Haren, Neeltje E M; van Baal, G Caroline M; Brouwer, Rachel M; Brans, Rachel G H; Schnack, Hugo G; Kahn, René S; Hulshoff Pol, Hilleke E

    2016-06-01

    Cortical thickness and surface area changes have repeatedly been found in schizophrenia. Whether progressive loss in cortical thickness and surface area are mediated by genetic or disease related factors is unknown. Here we investigate to what extent genetic and/or environmental factors contribute to the association between change in cortical thickness and surface area and liability to develop schizophrenia. Longitudinal magnetic resonance imaging study over a 5-year interval. Monozygotic (MZ) and dizygotic (DZ) twin pairs discordant for schizophrenia were compared with healthy control twin pairs using repeated measures analysis of variance (RM-ANOVA) and structural equation modeling (SEM). Twins discordant for schizophrenia and healthy control twins were recruited from the twin cohort at the University Medical Centre Utrecht, The Netherlands. A total of 90 individuals from 46 same sex twin pairs were included: 9 MZ and 10 DZ discordant for schizophrenia and 14 MZ and 13 (11 complete and 2 incomplete) DZ healthy twin-pairs. Age varied between 19 and 57years. Higher genetic liability for schizophrenia was associated with progressive global thinning of the cortex, particularly of the left superior temporal cortex. Higher environmental liability for schizophrenia was associated with global attenuated thinning of the cortex, and including of the left superior temporal cortex. Cortical surface area change was heritable, but not significantly associated with higher genetic or environmental liability for schizophrenia. Excessive cortical thinning, particularly of the left superior temporal cortex, may represent a genetic risk marker for schizophrenia. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Blood DNA methylation age is not associated with cognitive functioning in middle-aged monozygotic twins

    DEFF Research Database (Denmark)

    Starnawska, A; Tan, Q; Lenart, A

    2016-01-01

    The epigenetic clock, also known as DNA methylation age (DNAmAge), represents age-related changes of DNA methylation at multiple sites of the genome and is suggested to be a biomarker for biological age. Elevated blood DNAmAge is associated with all-cause mortality, with the strongest effects...... reported in a recent intrapair twin study where epigenetically older twins had increased mortality risk in comparison to their co-twins. In the study presented here, we hypothesize that DNAmAge in blood is associated with cross-sectional and longitudinal cognitive abilities in middle-aged individuals....... In 486 monozygotic twins, we investigated the association of DNAmAge, difference between DNAmAge and chronological age and age acceleration with cognition. Despite using a powerful paired twin design, we found no evidence for association of blood DNAmAge with cognitive abilities. This observation...

  14. Reared-Apart Chinese Twins: Chance Discovery/Twin-Based Research: Twin Study of Media Use; Twin Relations Over the Life Span; Breast-Feeding Opposite-Sex Twins/Print and Online Media: Twins in Fashion; Second Twin Pair Born to Tennis Star; Twin Primes; Twin Pandas.

    Science.gov (United States)

    Segal, Nancy L

    2017-04-01

    A January 2017 reunion of 10-year-old reared-apart Chinese twin girls was captured live on ABC's morning talk show Good Morning America, and rebroadcast on their evening news program Nightline. The twins' similarities and differences, and their participation in ongoing research will be described. This story is followed by reviews of twin research concerning genetic and environmental influences on media use, twin relations across the lifespan and the breast-feeding of opposite-sex twins. Popular interest items include twins in fashion, the second twin pair born to an internationally renowned tennis star, twin primes and twin pandas.

  15. Genetic and Environmental Etiologies of Reading Difficulties: DeFries-Fulker Analysis of Reading Performance Data from Twin Pairs and Their Non-Twin Siblings

    Science.gov (United States)

    Astrom, Raven L.; Wadsworth, Sally J.; Olson, Richard K.; Willcutt, Erik G.; DeFries, John C.

    2012-01-01

    Reading performance data from 254 pairs of identical (MZ) and 420 pairs of fraternal (DZ) twins, 8.0 to 20.0 years of age, were subjected to multiple regression analyses. An extension of the DeFries-Fulker (DF) analysis (DeFries & Fulker, 1985, 1988) that facilitated inclusion of data from 303 of their nontwin siblings was employed. In addition to…

  16. Birth size and gestational age in opposite-sex twins as compared to same-sex twins

    DEFF Research Database (Denmark)

    Jelenkovic, Aline; Sund, Reijo; Yokoyama, Yoshie

    2018-01-01

    It is well established that boys are born heavier and longer than girls, but it remains unclear whether birth size in twins is affected by the sex of their co-twin. We conducted an individual-based pooled analysis of 21 twin cohorts in 15 countries derived from the COllaborative project of Develo......It is well established that boys are born heavier and longer than girls, but it remains unclear whether birth size in twins is affected by the sex of their co-twin. We conducted an individual-based pooled analysis of 21 twin cohorts in 15 countries derived from the COllaborative project....... In girls, birth size was not associated (5 g birth weight; 95% CI -8 to -18 and -0.089 cm birth length; 95% CI -0.202 to 0.025) with the sex of the co-twin. Gestational age was slightly shorter in boy-boy pairs than in boy-girl and girl-girl pairs. When birth size was standardized by gestational age......, the magnitude of the associations was attenuated in boys, particularly for birth weight. In conclusion, boys with a co-twin sister are heavier and longer at birth than those with a co-twin brother. However, these differences are modest and partly explained by a longer gestation in the presence of a co...

  17. Birth weight and gestational age on retinopathy of prematurity in discordant twins in China

    Directory of Open Access Journals (Sweden)

    Zong-Hua Wang

    2014-08-01

    Full Text Available AIM:To assess the relative effect of birth weight and gestational age on retinopathy of prematurity (ROP using preterm twin pairs discordant for birth weigh in a tertiary neonatal intensive care unit in China.METHODS: Fifty-six discordant twin pairs of 112 preterm infants were retrospectively analyzed. The twin pairs were divided into two subgroups based on birth weight in each pair. The occurrence of ROP and severe ROP requiring treatment were compared between the lower birth weight infants and their co-twins with the higher birth weight. Some neonatal morbidities related to prematurity and neonatal characteristics were also compared between the twin pairs.RESULTS: Based on the univariate analysis, gestational age and birth weight were significantly associated with the occurrence and progression of ROP. But no significant differences in ROP between larger and smaller infants were observed in the twin-paired analysis. The incidence of neonatal morbidities regarding respiratory distress syndrome (RDS, patent ductus arteriosus (PDA, intraventricular hemorrhage (IVH, sepsis and neonatal characteristics regarding gender distribution, one- and five-minute Apgar score, postnatal steroid treatment, blood transfusion, supplemental oxygen therapy, and mechanical ventilation were not different between the twins. However, gestational age of ≤28wk was significantly associated with significantly higher rates of ROP and severe ROP.CONCLUSION: Gestational age is a better predictor of ROP than birth weight in the twin-paired study.

  18. Aging and communication in the twin paradox

    International Nuclear Information System (INIS)

    De Wolf, David A

    2016-01-01

    The twin paradox of the special theory of relativity has given rize to a large body of literature discussing its implications. In its standard form, the traveler changes velocity only at the destination of the trip, so that he appears to perceive an improbably instantaneous and non-continuous change in age of the stationary twin. In this work, a smooth velocity/acceleration profile is used that allows the abrupt velocity-change case as a limit. All gravitational effects are ignored in this treatment. Aside from mutual perception of simultaneous clock times in an accelerating frame, constant communication of clock times between the twins by means of (digital) light signals is shown to be possible, in principle if not in practice. (paper)

  19. Prevalence of Polycystic Ovary Syndrome in Women from Opposite-Sex Twin Pairs

    NARCIS (Netherlands)

    Kuijper, E.A.M.; Vink, J.M.; Lambalk, C.B.; Boomsma, D.I.

    2009-01-01

    Introduction: Intrauterine androgens of a male fetus may influence the female fetus in opposite-sex twin pairs. Because female intrauterine overexposure to androgens could lead to polycystic ovary syndrome (PCOS), the prevalence of PCOS should be higher in women from opposite-sex twin pairs.

  20. Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study.

    Science.gov (United States)

    Aaltonen, Sari; Latvala, Antti; Rose, Richard J; Pulkkinen, Lea; Kujala, Urho M; Kaprio, Jaakko; Silventoinen, Karri

    2015-10-01

    Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development was assessed by the parents' report of whether one of the co-twins had been ahead of the other in different indicators of motor skill development in childhood. Leisure-time physical activity (MET·h·d) was self-reported by the twins in young adulthood and adulthood. Statistical analyses included conditional and ordinary linear regression models within twin pairs. Using all activity-discordant twin pairs, the within-pair difference in a sum score of motor development in childhood predicted the within-pair difference in the leisure-time physical activity level in young adulthood (P men and women.

  1. Factors that affect skin aging: a cohort-based survey on twins.

    Science.gov (United States)

    Martires, Kathryn J; Fu, Pingfu; Polster, Amy M; Cooper, Kevin D; Baron, Elma D

    2009-12-01

    To identify environmental factors that correlate with skin photoaging, controlling for genetic susceptibility by using a questionnaire administered to twins. The survey collected information about each participant's Fitzpatrick type, history of skin cancer, smoking and drinking habits, and weight from a cohort of twins. Clinicians then assigned a clinical photodamage score to each participant. The annual Twins Days Festival in Twinsburg, Ohio. A voluntary cohort of twins from the general community, mostly from Ohio, Pennsylvania, and the northeastern United States. The survey was completed on a voluntary basis by sets of monozygotic (MZ) and dizygotic (DZ) twins. A total of 130 surveys taken by 65 complete twin pairs were analyzed. Skin aging was assessed using a validated photographic scale of photodamage, graded by such characteristics as wrinkling and pigmentation change. Photodamage scores among twins of a pair, whether MZ or DZ, were highly correlated (P = .92). Factors found to predict higher photodamage include history of skin cancer (P < .001), zygosity status (MZ vs DZ) (P = .001), weight (P = .02), and cigarette smoking (P = .046). Alcohol consumption was significantly associated with lower photodamage scores (P = .003). The study of twins provides a unique opportunity to control for genetic susceptibility in order to elucidate environmental influences on skin aging. The relationships found between smoking, weight, sunscreen use, skin cancer, and photodamage in these twin pairs may help to motivate the reduction of risky behaviors.

  2. Objective assessment of facial skin aging and the associated environmental factors in Japanese monozygotic twins.

    Science.gov (United States)

    Ichibori, Ryoko; Fujiwara, Takashi; Tanigawa, Tomoko; Kanazawa, Shigeyuki; Shingaki, Kenta; Torii, Kosuke; Tomita, Koichi; Yano, Kenji; Sakai, Yasuo; Hosokawa, Ko

    2014-06-01

    Twin studies, especially those involving monozygotic (MZ) twins, facilitate the analysis of factors affecting skin aging while controlling for age, gender, and genetic susceptibility. The purpose of this study was to objectively assess various features of facial skin and analyze the effects of environmental factors on these features in MZ twins. At the Osaka Twin Research Center, 67 pairs of MZ twins underwent medical interviews and photographic assessments, using the VISIA(®) Complexion Analysis System. First, the average scores of the right and left cheek skin spots, wrinkles, pores, texture, and erythema were calculated; the differences between the scores were then compared in each pair of twins. Next, using the results of medical interviews and VISIA data, we investigated the effects of environmental factors on skin aging. The data were analyzed using Pearson's correlation coefficient test and the Wilcoxon signed-rank test. The intrapair differences in facial texture scores significantly increased as the age of the twins increased (P = 0.03). Among the twin pairs who provided answers to the questions regarding history differences in medical interviews, the twins who smoked or did not use skin protection showed significantly higher facial texture or wrinkle scores compared with the twins not exposed to cigarettes or protectants (P = 0.04 and 0.03, respectively). The study demonstrated that skin aging among Japanese MZ twins, especially in terms of facial texture, was significantly influenced by environmental factors. In addition, smoking and skin protectant use were important environmental factors influencing skin aging. © 2014 The Authors Journal of Cosmetic Dermatology Published by Wiley Periodicals, Inc.

  3. Sports pairs: insights on athletic talent; research reviews: twins with leukemia; parents and twins.

    Science.gov (United States)

    Segal, Nancy L

    2007-06-01

    Twin research exploring genetic and environmental influences on athletic interests and talents is reviewed. Illustrative examples of twin athletes representing a variety of sports activities are presented. This is followed by an overview of twin studies offering critical insights into the onset and progress of leukemia. In the last section, timely events involving twins and parents of twins will be described--each case provides a new look at an old question.

  4. Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins.

    Science.gov (United States)

    Steves, Claire J; Mehta, Mitul M; Jackson, Stephen H D; Spector, Tim D

    2016-01-01

    Many observational studies have shown a protective effect of physical activity on cognitive ageing, but interventional studies have been less convincing. This may be due to short time scales of interventions, suboptimal interventional regimes or lack of lasting effect. Confounding through common genetic and developmental causes is also possible. We aimed to test whether muscle fitness (measured by leg power) could predict cognitive change in a healthy older population over a 10-year time interval, how this performed alongside other predictors of cognitive ageing, and whether this effect was confounded by factors shared by twins. In addition, we investigated whether differences in leg power were predictive of differences in brain structure and function after 12 years of follow-up in identical twin pairs. A total of 324 healthy female twins (average age at baseline 55, range 43-73) performed the Cambridge Neuropsychological Test Automated Battery (CANTAB) at two time points 10 years apart. Linear regression modelling was used to assess the relationships between baseline leg power, physical activity and subsequent cognitive change, adjusting comprehensively for baseline covariates (including heart disease, diabetes, blood pressure, fasting blood glucose, lipids, diet, body habitus, smoking and alcohol habits, reading IQ, socioeconomic status and birthweight). A discordant twin approach was used to adjust for factors shared by twins. A subset of monozygotic pairs then underwent magnetic resonance imaging. The relationship between muscle fitness and brain structure and function was assessed using linear regression modelling and paired t tests. A striking protective relationship was found between muscle fitness (leg power) and both 10-year cognitive change [fully adjusted model standardised β-coefficient (Stdβ) = 0.174, p = 0.002] and subsequent total grey matter (Stdβ = 0.362, p = 0.005). These effects were robust in discordant twin analyses, where within-pair

  5. Risk of chronic bronchitis in twin pairs discordant for smoking

    DEFF Research Database (Denmark)

    Meteran, Howraman; Thomsen, Simon Francis; Harmsen, Lotte

    2012-01-01

    It is well known that smoking is a major risk factor for lung disease and respiratory symptoms. We examined the association between smoking and the risk of chronic bronchitis in a large twin sample.......It is well known that smoking is a major risk factor for lung disease and respiratory symptoms. We examined the association between smoking and the risk of chronic bronchitis in a large twin sample....

  6. Differences in frontal and limbic brain activation in a small sample of monozygotic twin pairs discordant for severe stressful life events

    Directory of Open Access Journals (Sweden)

    Detre A. Godinez

    2016-12-01

    Full Text Available Monozygotic twin pairs provide a valuable opportunity to control for genetic and shared environmental influences while studying the effects of nonshared environmental influences. The question we address with this design is whether monozygotic twins selected for discordance in exposure to severe stressful life events during development (before age 18 demonstrate differences in brain activation during performance of an emotional word-face Stroop task. In this study, functional magnetic resonance imaging was used to assess brain activation in eighteen young adult twins who were discordant in exposure to severe stress such that one twin had two or more severe events compared to their control co-twin who had no severe events. Twins who experienced higher levels of stress during development, compared to their control co-twins with lower stress, exhibited significant clusters of greater activation in the ventrolateral and medial prefrontal cortex, basal ganglia, and limbic regions. The control co-twins showed only the more typical recruitment of frontoparietal regions thought to be important for executive control of attention and maintenance of task goals. Behavioral performance was not significantly different between twins within pairs, suggesting the twins with stress recruited additional neural resources associated with affective processing and updating working memory when performing at the same level. This study provides a powerful glimpse at the potential effects of stress during development while accounting for shared genetic and environmental influences.

  7. Heritability of Biomarkers of Oxidized Lipoproteins: Twin Pair Study.

    Science.gov (United States)

    Rao, Fangwen; Schork, Andrew J; Maihofer, Adam X; Nievergelt, Caroline M; Marcovina, Santica M; Miller, Elizabeth R; Witztum, Joseph L; O'Connor, Daniel T; Tsimikas, Sotirios

    2015-07-01

    To determine whether biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) (Lp[a]) is a heritable risk factor and carrier of oxidized phospholipids (OxPL). We measured oxidized phospholipids on apolipoprotein B-containing lipoproteins (OxPL-apoB), Lp(a), IgG, and IgM autoantibodies to malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes in 386 monozygotic and dizygotic twins to estimate trait heritability (h(2)) and determine specific genetic effects among traits. A genome-wide linkage study followed by genetic association was performed. The h(2) (scale: 0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiological, inflammatory, or lipid traits. h(2) of IgM malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49; Plipoprotein and copper oxidized low-density lipoprotein, and apoB-immune complexes. Sib-pair genetic linkage of the Lp(a) trait revealed that single nucleotide polymorphism rs10455872 was significantly associated with OxPL-apoB after adjusting for Lp(a). OxPL-apoB and other biomarkers of oxidized lipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis. © 2015 American Heart Association, Inc.

  8. Risk factors for Staphylococcus aureus nasal colonization in Danish middle-aged and elderly twins

    DEFF Research Database (Denmark)

    Andersen, P S; Larsen, Lisbeth Aagaard; Fowler, V G

    2013-01-01

    on S. aureus carriage in Danish middle-aged and elderly twins, which indicated no significant heritability that could account for the observed S. aureus carriage. In the present study, we performed a questionnaire-based study of S. aureus colonization on the same cohort of 2,196 Danish middle......-aged and elderly twins to identify specific risk factors for S. aureus nasal colonization, including analyzing the paired twins (n = 478) that were discordant for S. aureus colonization. We found associations between risk factors and S. aureus nasal colonization among middle-aged and elderly twins, including age......, male gender, psoriasis, and atopic diseases. Also, present living on a farm is clearly associated with S. aureus colonization, while smoking had a borderline statistically significant protective effect....

  9. Childhood social class and cognitive aging in the Swedish Adoption/Twin Study of Aging.

    Science.gov (United States)

    Ericsson, Malin; Lundholm, Cecilia; Fors, Stefan; Dahl Aslan, Anna K; Zavala, Catalina; Reynolds, Chandra A; Pedersen, Nancy L

    2017-07-03

    In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and parental social class based on the Swedish socioeconomic index. Cognitive ability included a general factor and the four domains of verbal, fluid, memory, and perceptual speed. Latent growth curve models of the longitudinal data tested whether level and change in cognitive performance differed as a function of childhood social class. Between-within twin-pair analyses were performed on twins reared apart to assess familial confounding. Childhood social class was significantly associated with mean-level cognitive performance at age 65 y, but not with rate of cognitive change. The association decreased in magnitude but remained significant after adjustments for level of education and the degree to which the rearing family was supportive toward education. A between-pair effect of childhood social class was significant in all cognitive domains, whereas within-pair estimates were attenuated, indicating genetic confounding. Thus, childhood social class is important for cognitive performance in adulthood on a population level, but the association is largely attributable to genetic influences.

  10. Aging Trajectories in Different Body Systems Share Common Environmental Etiology: The Healthy Aging Twin Study (HATS).

    Science.gov (United States)

    Moayyeri, Alireza; Hart, Deborah J; Snieder, Harold; Hammond, Christopher J; Spector, Timothy D; Steves, Claire J

    2016-02-01

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal clinical data were collected on 3,508 female twins in the TwinsUK registry (complete pairs:740 monozygotic (MZ), 986 dizygotic (DZ), mean age at entry 48.9 ± 10.4, range 18-75 years; mean follow-up 10.2 ± 2.8 years, range 4-17.8 years). Panel data on multiple age-related variables were used to estimate biological ages for each individual at each time point, in linear mixed effects models. A weighted average approach was used to combine variables within predefined body system groups. Aging trajectories for each system in each individual were then constructed using linear modeling. Multivariate structural equation modeling of these aging trajectories showed low genetic effects (heritability), ranging from 2% in metabolic aging to 22% in cardiovascular aging. However, we found a significant effect of shared environmental factors on the variations in aging trajectories in cardiovascular (54%), skeletal (34%), morphometric (53%), and metabolic systems (53%). The remainder was due to environmental factors unique to each individual plus error. Multivariate Cholesky decomposition showed that among aging trajectories for various body systems there were significant and substantial correlations between the unique environmental latent factors as well as shared environmental factors. However, there was no evidence for a single common factor for aging. This study, the first of its kind in aging, suggests that diverse organ systems share non-genetic sources of variance for aging trajectories. Confirmatory studies are needed using population-based twin cohorts and alternative methods of handling missing data.

  11. Highlights from the 15th International Congress of Twin Studies/Twin Research: Differentiating MZ Co-twins Via SNPs; Mistaken Infant Twin-Singleton Hospital Registration; Narcolepsy With Cataplexy; Hearing Loss and Language Learning/Media Mentions: Broadway Musical Recalls Conjoined Hilton Twins; High Fashion Pair; Twins Turn 102; Insights From a Conjoined Twin Survivor.

    Science.gov (United States)

    Segal, Nancy L

    2015-02-01

    Highlights from the 15th International Congress of Twin Studies are presented. The congress was held November 16-19, 2014 in Budapest, Hungary. This report is followed by summaries of research addressing the differentiation of MZ co-twins by single nucleotide polymorphisms (SNPs), an unusual error in infant twin-singleton hospital registration, twins with childhood-onset narcolepsy with cataplexy, and the parenting effects of hearing loss in one co-twin. Media interest in twins covers a new Broadway musical based on the conjoined twins Violet and Daisy Hilton, male twins becoming famous in fashion, twins who turned 102 and unique insights from a conjoined twin survivor. This article is dedicated to the memory of Elizabeth (Liz) Hamel, DZA twin who met her co-twin for the first time at age seventy-eight years. Liz and her co-twin, Ann Hunt, are listed in the 2015 Guinness Book of Records as the longest separated twins in the world.

  12. Twin boundary cavitation in aged type 304 stainless steel

    International Nuclear Information System (INIS)

    Sikka, V.K.; Swindeman, R.W.; Brinkman, C.R.

    1975-10-01

    A transition from grain to twin boundary cavitation was observed in aged-and-creep-tested type 304 stainless steel. Evidence of twin boundary cavitation has also been observed for unaged material under certain test conditions. This same behavior was also found in aged type 316 stainless steel. Several possible reasons have been suggested for the absence of frequently observed grain boundary cavitation

  13. Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge

    OpenAIRE

    Bondia-Pons, Isabel; Maukonen, Johanna; Mattila, Ismo; Rissanen, Aila; Saarela, Maria; Kaprio, Jaakko; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Hy?tyl?inen, Tuulia; Pietil?inen, Kirsi H.; Ore?i?, Matej

    2014-01-01

    Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (...

  14. Cognitive Functioning after Surgery in Middle-aged and Elderly Danish Twins

    DEFF Research Database (Denmark)

    Dokkedal, Unni; Hansen, Tom G; Rasmussen, Lars S

    2016-01-01

    ,503 middle-aged and elderly twins. METHODS: Results from five cognitive tests were compared in twins exposed to surgery, classified as major, minor, hip and knee replacement, or other, with those of a reference group without surgery using linear regression adjusted for sex and age. Genetic and shared......BACKGROUND: Postoperative cognitive dysfunction is common, but it remains unclear whether there are long-term adverse cognitive effects of surgery combined with anesthesia. The authors examined the association between exposure to surgery and level of cognitive functioning in a sample of 8...... environmental confounding was addressed in intrapair analyses of 87 monozygotic and 124 dizygotic same-sexed twin pairs in whom one had a history of major surgery and the other did not. RESULTS: Statistically significantly lower composite cognitive score was found in twins with at least one major surgery...

  15. Motives for and barriers to physical activity in twin pairs discordant for leisure time physical activity for 30 years.

    Science.gov (United States)

    Aaltonen, S; Leskinen, T; Morris, T; Alen, M; Kaprio, J; Liukkonen, J; Kujala, U

    2012-02-01

    Long-term persistent physical activity is important in the prevention of chronic diseases, but a large number of people do not participate in physical activity to obtain health benefits. The purpose of this study was to examine the motives and perceived barriers to long-term engagement in leisure time physical activity. Same-sex twin pairs (N=16, mean age 60) discordant for physical activity over 30 years were identified from the Finnish Twin Cohort. We evaluated participants' physical activity motivation with the 73-item Recreational Exercise Motivation Measure and assessed barriers to physical activity with a 25-item questionnaire. The characteristics of physical activity motivation and perceived barriers between the active and inactive co-twins were analysed using paired tests. Motives related to the sub-dimensions of enjoyment and physical fitness and psychological state were the most important reasons for participation in physical activity among all the twin individuals analysed. The sub-dimensions mastery (p=0.018, Cohen's d=0.76), physical fitness (p=0.029, Cohen's d=0.69), and psychological state (p=0.039, Cohen's d=0.65) differed significantly between active and inactive co-twins. More than half of the participants reported no reasons for not being physically active. If reasons existed, participation in physical activity was deterred mostly by pain and various health problems. This study found no differences in perceived barriers between active and inactive co-twins. We conclude from our results that the main factors promoting persistent leisure time physical activity were participants' wish to improve or maintain their physical skills or techniques, a feeling that exercise would improve their mental and physical health and that they found the activity enjoyable. This study helps us understand the importance of the role of motives and the minor role of perceived barriers for engagement in persistent physical activity. © Georg Thieme Verlag KG Stuttgart

  16. Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge.

    Science.gov (United States)

    Bondia-Pons, Isabel; Maukonen, Johanna; Mattila, Ismo; Rissanen, Aila; Saarela, Maria; Kaprio, Jaakko; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Hyötyläinen, Tuulia; Pietiläinen, Kirsi H; Orešič, Matej

    2014-09-01

    Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (body mass index difference >3 kg/m(2)). Nine concordant monozygotic pairs were examined as control pairs. Fecal samples were analyzed to assess diversity of the major bacterial groups by using 5 different validated bacterial group specific denaturing gradient gel electrophoresis methods. No differences in fecal bacterial diversity were detected when comparing co-twins discordant for weight (ANOVA, P<0.05). We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity. Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially (paired t tests, FDR q<0.05). We also found that specific bacterial groups were associated with postprandial changes of specific metabolites. Our findings underline important roles of genetic and early life factors in the regulation of postprandial metabolite levels. © FASEB.

  17. The Spread of Substance Use and Delinquency between Adolescent Twins

    Science.gov (United States)

    Laursen, Brett; Hartl, Amy C.; Vitaro, Frank; Brendgen, Mara; Dionne, Ginette; Boivin, Michel

    2017-01-01

    This investigation examines the spread of problem behaviors (substance use and delinquency) between twin siblings. A sample of 628 twins (151 male twin pairs and 163 female twin pairs) drawn from the Quebec Newborn Twin Study completed inventories describing delinquency and substance use at ages 13, 14, and 15. A 3-wave longitudinal actor-partner…

  18. MZ twin pairs or MZ singletons in population family-based GWAS? More power in pairs

    NARCIS (Netherlands)

    Minica, C.C.; Boomsma, D.I.; Vink, J.M.; Dolan, C.V.

    2014-01-01

    Family-based genome-wide association studies (GWAS) involve testing the genetic association of (many) genetic variants with the phenotype of interest, while taking into account the relatedness among family members. Occasionally in family-based GWAS, including monozygotic (MZ) twins, the data from

  19. Low birth weight is associated with NIDDM in discordant monozygotic and dizygotic twin pairs

    DEFF Research Database (Denmark)

    Poulsen, P; Vaag, Allan; Kyvik, K O

    1997-01-01

    between the putative "NIDDM susceptibility genotype" and a genetically determined low weight at birth. It is also unclear whether differences in gestational age, maternal height, birth order and/or sex could explain the association. Twins are born of the same mother and have similar gestational ages......Previous studies have demonstrated an association between low weight at birth and risk of later development of non-insulin-dependent diabetes mellitus (NIDDM). It is not known whether this association is due to an impact of intrauterine malnutrition per se, or whether it is due to a coincidence....... Furthermore, monozygotic (MZ) twins have identical genotypes. Original midwife birth weight record determinations were traced in MZ and dizygotic (DZ) twins discordant for NIDDM. Birth weights were lower in the NIDDM twins (n = 2 x 14) compared with both their identical (MZ; n = 14) and non-identical (DZ; n...

  20. No Evidence of Genetic Mediation in the Association Between Birthweight and Academic Performance in 2,413 Danish Adolescent Twin Pairs

    DEFF Research Database (Denmark)

    Petersen, Inge; Jensen, Vibeke Myrup; McGue, Matt K.

    2009-01-01

    Abstract Evidence of a positive association between birthweight and IQ has been established in several studies. Analyses of within twin pair differences in birthweight and IQ have been used to shed light on the basis of the association. The strength of this approach is the possibility of controll...... and school achievements at age 16. For both sexes we observed a monotonic increase in academic performance with increasing percentiles of birthweight. However, we did not find that this association is due to genetic mediation....... twin studies find no evidence of such mediation. In the present study we use a large population-based national register study of 2,413 Danish twin-pairs from birth cohorts 1986-1990, of which we have zygosity information on 74%. We perform individual level as well as intra-pair analyses of birthweight...

  1. No evidence of genetic mediation in the association between birthweight and academic performance in 2,413 danish adolescent twin pairs

    DEFF Research Database (Denmark)

    Petersen, Inge; Jensen, Vibeke Myrup; McGue, Matt

    2009-01-01

    Abstract Evidence of a positive association between birthweight and IQ has been established in several studies. Analyses of within twin pair differences in birthweight and IQ have been used to shed light on the basis of the association. The strength of this approach is the possibility of controll...... and school achievements at age 16. For both sexes we observed a monotonic increase in academic performance with increasing percentiles of birthweight. However, we did not find that this association is due to genetic mediation....... twin studies find no evidence of such mediation. In the present study we use a large population-based national register study of 2,413 Danish twin-pairs from birth cohorts 1986-1990, of which we have zygosity information on 74%. We perform individual level as well as intra-pair analyses of birthweight...

  2. Genetic and environmental etiologies of reading difficulties: DeFries-Fulker analysis of reading performance data from twin pairs and their nontwin siblings

    OpenAIRE

    Astrom, Raven L.; Wadsworth, Sally J.; Olson, Richard K.; Willcutt, Erik G.; DeFries, John C.

    2012-01-01

    Reading performance data from 254 pairs of identical (MZ) and 420 pairs of fraternal (DZ) twins, 8.0 to 20.0 years of age, were subjected to multiple regression analyses. An extension of the DeFries-Fulker (DF) analysis (DeFries & Fulker, 1985, 1988) that facilitated inclusion of data from 303 of their nontwin siblings was employed. In addition to providing estimates of heritability, this analysis yields a test of the difference between shared environmental influences for twins versus sibling...

  3. Biotin-dependent functions in adiposity: a study of monozygotic twin pairs.

    Science.gov (United States)

    Järvinen, E; Ismail, K; Muniandy, M; Bogl, L H; Heinonen, S; Tummers, M; Miettinen, S; Kaprio, J; Rissanen, A; Ollikainen, M; Pietiläinen, K H

    2016-05-01

    Biotin acts as a coenzyme for carboxylases regulating lipid and amino-acid metabolism. We investigated alterations of the biotin-dependent functions in obesity and the downstream effects of biotin restriction in adipocytes in vitro. Twenty-four monozygotic twin pairs discordant for body mass index (BMI). Mean within-pair difference (heavy-lean co-twin, Δ) of BMI was 6.0 kg m(-2) (range 3.1-15.2 kg m(-)(2)). Adipose tissue (AT) DNA methylation, gene expression of AT and adipocytes, and leukocytes (real-time quantitative PCR), serum biotin, C-reactive protein (CRP) and triglycerides were measured in the twins. Human adipocytes were cultured in low and control biotin concentrations and analyzed for lipid droplet content, mitochondrial morphology and mitochondrial respiration. The gene expression levels of carboxylases, PCCB and MCCC1, were upregulated in the heavier co-twins' leukocytes. ΔPCCB (r=0.91, P=0.0046) and ΔMCCC1 (r=0.79, P=0.036) correlated with ΔCRP within-pairs. Serum biotin levels were lower in the heavier (274 ng l(-1)) than in the lean co-twins (390 ng l(-1), P=0.034). ΔBiotin correlated negatively with Δtriglycerides (r=-0.56, P=0.045) within-pairs. In AT, HLCS and ACACB were hypermethylated and biotin cycle genes HLCS and BTD were downregulated (PBiotin-dependent carboxylases were downregulated (ACACA, ACACB, PCCB, MCCC2 and PC; Pbiotin had decreased lipid accumulation, altered mitochondrial morphology and deficient mitochondrial respiration. Biotin-dependent functions are modified by adiposity independent of genetic effects, and correlate with inflammation and hypertriglyceridemia. Biotin restriction decreases lipid accumulation and respiration, and alters mitochondrial morphology in adipocytes.

  4. Gut resistome development in healthy twin pairs in the first year of life.

    Science.gov (United States)

    Moore, Aimee M; Ahmadi, Sara; Patel, Sanket; Gibson, Molly K; Wang, Bin; Ndao, Malick I; Deych, Elena; Shannon, William; Tarr, Phillip I; Warner, Barbara B; Dantas, Gautam

    2015-01-01

    The early life of the human host marks a critically important time for establishment of the gut microbial community, yet the developmental trajectory of gut community-encoded resistance genes (resistome) is unknown. We present a longitudinal study of the fecal antibiotic resistome of healthy amoxicillin-exposed and antibiotic-naive twins and their mothers during the first year of life. We extracted metagenomic DNA (mgDNA) from fecal samples collected from three healthy twin pairs at three timepoints (1 or 2 months, 6 or 7 months, and 11 months) and from their mothers (collected at delivery). The mgDNA was used to construct metagenomic expression libraries in an Escherichia coli host. These libraries were screened for antibiotic resistance, and functionally selected resistance genes were sequenced and annotated. A diverse fecal resistome distinct from the maternal resistome was apparent by 2 months of age, and infants' fecal resistomes included resistance to clinically important broad-spectrum beta-lactam antibiotics (e.g., piperacillin-tazobactam, aztreonam, cefepime) not found in their mothers. Dissemination of resistance genes among members of a given family was positively correlated with sharing of those same resistance genes between unrelated families, potentially identifying within-family sharing as a marker of resistance genes emerging in the human community at large. Finally, we found a distinct developmental trajectory for a community-encoded function: chloramphenicol resistance. All study subjects at all timepoints harbored chloramphenicol resistance determinants, but multidrug efflux pumps (rarely found in mothers) were the primary effectors of chloramphenicol resistance in young infants. Chloramphenicol acetyltransferases were more common in mothers than in infants and were found in nearly all the infants at later timepoints. Our results suggest that healthy 1-2-month-old infants' gut microbes harbor clinically relevant resistance genes distinct from

  5. The relationship between subjective well-being and mortality within discordant twin pairs from two independent samples

    DEFF Research Database (Denmark)

    Saunders, Gretchen R B; Elkins, Irene J; Christensen, Kaare

    2018-01-01

    Prior research has shown robust associations between greater subjective well-being (SWB) and reduced mortality. Whether this observed association is causal in nature or due instead to confounding genetic or environmental factors affecting both SWB and mortality is not well understood. We used a c...... when accounting for demographic factors, physical health, and cognitive functioning. (PsycINFO Database Record...... a combined sample of 6,802 twins drawn from two cohorts: the Longitudinal Study of Middle-Aged Danish Twins (MADT; N = 2,815, baseline age between 45 and 69 years, M = 56.8, SD = 6.4) and the Longitudinal Study of Aging Danish Twins (LSADT; N = 3,987, baseline age between 70 and 97 years, M = 76.6, SD = 4...... of SWB on reduced mortality remained significant within both MZ and DZ pairs, suggesting that the association is independent of genetic and nonshared environmental confounding factors. These findings, which generalized across both younger (MADT) and older (LSADT) cohorts of adults, remained significant...

  6. Prosocial and self-interested intra-twin pair behavior in monozygotic and dizygotic twins in the early to middle childhood transition.

    Science.gov (United States)

    Yirmiya, Karen; Segal, Nancy L; Bloch, Guy; Knafo-Noam, Ariel

    2018-04-06

    Several related and complementary theoretical frameworks have been proposed to explain the existence of prosocial behavior, despite its potential fitness cost to the individual. These include kin selection theory, proposing that organisms have a propensity to help those to whom they are genetically related, and reciprocity, referring to the benefit of being prosocial, depending on past and future mutual interactions. A useful paradigm to examine prosociality is to compare mean levels of this behavior between monozygotic (MZ) and dizygotic (DZ) twins. Here, we examined the performance of 883 6.5-year-old twins (139 MZ and 302 DZ same-sex 6.5-year-old full twin pairs) in the Differential Productivity Task. In this task, the twins' behaviors were observed under two conditions: working for themselves vs. working for their co-twin. There were no significant differences between the performances of MZ and DZ twins in the prosocial condition of the task. Correlations within the twin dyads were significantly higher in MZ than DZ twins in the self-interested condition. However, similar MZ and DZ correlations were found in the prosocial condition, supporting the role of reciprocity in twins' prosociality towards each other. © 2018 John Wiley & Sons Ltd.

  7. Hormone replacement therapy improves contractile function and myonuclear organization of single muscle fibres from postmenopausal monozygotic female twin pairs.

    Science.gov (United States)

    Qaisar, Rizwan; Renaud, Guillaume; Hedstrom, Yvette; Pöllänen, Eija; Ronkainen, Paula; Kaprio, Jaakko; Alen, Markku; Sipilä, Sarianna; Artemenko, Konstantin; Bergquist, Jonas; Kovanen, Vuokko; Larsson, Lars

    2013-05-01

    Ageing is associated with a decline in muscle mass and strength leading to increased physical dependency in old age. Postmenopausal women experience a greater decline than men of similar age in parallel with the decrease in female sex steroid hormone production. We recruited six monozygous female twin pairs (55-59 years old) where only one twin pair was on hormone replacement therapy (HRT use = 7.8 ± 4.3 years) to investigate the association of HRT with the cytoplasmic volume supported by individual myonuclei (myonuclear domain (MND) size,) together with specific force at the single fibre level. HRT use was associated with a significantly smaller (∼27%; P muscle fibres expressing the type I but not the IIa myosin heavy chain (MyHC) isoform. In comparison to non-users, higher specific force was recorded in HRT users both in muscle fibres expressing type I (∼27%; P fibre-type dependent, i.e. the higher specific force in fast-twitch muscle fibres was primarily caused by higher force per cross-bridge while slow-twitch fibres relied on both a higher number and force per cross-bridge. HRT use had no effect on fibre cross-sectional area (CSA), velocity of unloaded shortening (V0) and relative proportion of MyHC isoforms. In conclusion, HRT appears to have significant positive effects on both regulation of muscle contraction and myonuclei organization in postmenopausal women.

  8. A comparison of anthropometric, metabolic and reproductive characteristics of young adult women from opposite-sex and same sex twin pairs

    Directory of Open Access Journals (Sweden)

    Pirkko eKorsoff

    2014-03-01

    Full Text Available Background: Prenatal exposure to androgens has been linked to masculinization of several traits. We aimed to determine whether putative female intra-uterine exposure to androgens influences PCOS-related phenotypes, including anthropometric, metabolic and reproductive parameters using a twin design.Methods: Two cohorts of Finnish twins born in 1975-1979 and 1983-1987 formed the basis for the longitudinal FinnTwin16 (FT16 and FinnTwin12 (FT12 studies. Self-reported anthropometric characteristics, disease status and reproductive history were compared between 679 same-sex (SS and 789 opposite-sex (OS female twins (mean age ± SD: 34 ± 1.1 from the wave 5 of data collection in FT16. Serum lipid and lipoprotein subclass concentrations measured by nuclear magnetic resonance spectroscopy were compared in 226 SS and 169 OS female twins (mean age ± SD: 24 ± 2.1 from wave 4 of data collection in FT12 and FT16. Results: Anthropometric measures, the prevalence of hypertension and diabetes mellitus type 2 did not differ significantly between females from SS and OS twin pairs at age 34. Similarly, the prevalence of infertility, age at first pregnancy and number of induced and spontaneous abortions did not differ significantly between these two groups of women. The serum lipid and lipoprotein profile did not differ between females from SS and OS twins at age 24. Conclusion: We found no evidence that androgen overexposure of the female fetus affects obesity, metabolic profile or reproductive health in young adult females. However, these results do not exclude the possibility that prenatal androgen exposure in females could be adversely associated with intermediate phenotypes of PCOS later in life.

  9. A Possible Twin: The 1960s Twin Study Revisited/Twin Research: Twin-to-Twin Heart Transplantation; Distinguishing Monozygotic Twins; Twin Conceptions via Oocyte Donation; Factors Affecting Craniofacial Traits/In the Media: Triplet Delivery in the UK; Conjoined Twins and the Concept of Self; Colombian Twin Trainers; Skin Grafting to Save an Identical Co-Twin; Lack of Physical Flaws in Dolly the Cloned Sheep; Possible Conjoined Twins of Opposite-Sex; Passing of the Remaining Twin From the World's Longest Separated Pair.

    Science.gov (United States)

    Segal, Nancy L

    2018-04-01

    This article begins with the story of a 51-year-old Los Angeles, California man, Justin Goldberg, whose daughter caught a glimpse of his striking look-alike at a popular market. Many people have so-called doppelgängers, but this occurrence is especially intriguing - the individual in question, born in New York City in the mid-1960s to an unwed mother, was an adoptee placed by the Louise Wise Adoption Agency. This agency, under the guidance of a prominent psychiatrist, decided to place twins in separate homes. Some of these twin children were part of a controversial child development study that was hidden from them and their parents. Next, recent and current twin research on heart transplantation, distinguishing monozygotic co-twins, twin conceptions via oocyte donation and factors affecting craniofacial traits are summarized. The article concludes with highlights on twins in the media, specifically, a triplet delivery in the United Kingdom, self-concept and consciousness in conjoined twins, Colombian twin trainers, skin grafting to save an identical co-twin, lack of physical flaws in Dolly the cloned sheep, possible opposite-sex conjoined twins, and the passing of the remaining twin from the world's longest separated pair.

  10. Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H. [Ulleval Univ. Hospital, Oslo (Norway)] [and others

    1995-03-27

    Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore the result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.

  11. Twins for epigenetic studies of human aging and development

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; Thomassen, Mads

    2013-01-01

    Most of the complex traits including aging phenotypes are caused by the interaction between genome and environmental conditions and the interface of epigenetics may be a central mechanism. Although modern technologies allow us high-throughput profiling of epigenetic patterns already at genome level...... and environmental contributions to human diseases and complex traits. In the era of functional genomics, the valuable sample of twins is helping to bridge the gap between gene activity and the environments through epigenetic mechanisms unlimited by DNA sequence variations. We propose to extend the classical twin...... design to study the aging-related molecular epigenetic phenotypes and link them with environmental exposures especially early life events. Different study designs and application issues will be highlighted and novel approaches introduced with aim at making uses of twins in assessing the environmental...

  12. [A 20-year follow-up study of a sample of 50 pairs of twins with neurotic-psychosomatic disorders].

    Science.gov (United States)

    Muhs, A; Schepank, H; Manz, R

    1990-01-01

    As part of a research project, examination was made of a sample of 50 pairs of twins (21 pairs of identical twins, 16 pairs of non-identical twins of the same sex, and 13 pairs of male-female twins [n = 100 test persons]) between 1963 and 1969 and again recently after a period of 20 years. The index twins were drawn from among the patients who made use of the services of an out-patient psychotherapeutic clinic, and they were determined to be either psychoneurotic, character neurotic, or psychosomatically ill. The question examined was again one of nature vs. nurture. Identical twins showed a significantly higher similarity with regard to the seriousness of their neuroses and the manifestation of neurotic symptoms than did non-identical twins. Noticeable similarities existed in cases of depressive disturbances, disturbances of oral and aggressive behavior, and disturbances of interpersonal contact. With regard to the influence of variables in the environment, we examined the effect of factors in early childhood on neurotic development. Lack of a reference person, a negative attitude on the part of parents toward the child, etc., frustration within and outside the family have an effect on the manifestation of neuroses and on the course of their development. The influence of early childhood factors on the degree of neurotic disorder is still to be noted in the current point prevalence.

  13. Birth order, gestational age, and risk of delivery related perinatal death in twins: retrospective cohort study

    Science.gov (United States)

    Smith, Gordon C S; Pell, Jill P; Dobbie, Richard

    2002-01-01

    Objective To determine whether twins born second are at increased risk of perinatal death because of complications during labour and delivery. Design Retrospective cohort study. Setting Scotland, 1992 and 1997. Participants All twin births at or after 24 weeks' gestation, excluding twin pairs in which either twin died before labour or delivery or died during or after labour and delivery because of congenital abnormality, non-immune hydrops, or twin to twin transfusion syndrome. Main outcome measure Delivery related perinatal deaths (deaths during labour or the neonatal period). Results Overall, delivery related perinatal deaths were recorded for 23 first twins only and 23 second twins only of 1438 twin pairs born before 36 weeks (preterm) by means other than planned caesarean section (P>0.99). No deaths of first twins and nine deaths of second twins (P=0.004) were recorded among the 2436 twin pairs born at or after 36 weeks (term). Discordance between first and second twins differed significantly in preterm and term births (P=0.007). Seven of nine deaths of second twins at term were due to anoxia during the birth (2.9 (95% confidence interval 1.2 to 5.9) per 1000); five of these deaths were associated with mechanical problems with the second delivery following vaginal delivery of the first twin. No deaths were recorded among 454 second twins delivered at term by planned caesarean section. Conclusions Second twins born at term are at higher risk than first twins of death due to complications of delivery. Previous studies may not have shown an increased risk because of inadequate categorisation of deaths, lack of statistical power, inappropriate analyses, and pooling of data about preterm births and term births. What is already known on this topicIt is difficult to assess the wellbeing of second twins during labourDeliveries of second twins are at increased risk of mechanical problems, such as cord prolapse and malpresentation, after vaginal delivery of first twins

  14. Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age

    DEFF Research Database (Denmark)

    Yokoyama, Yoshie; Jelenkovic, Aline; Sund, Reijo

    2016-01-01

    of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer...

  15. Genetic and environmental contributions to body mass index: comparative analysis of monozygotic twins, dizygotic twins and same-age unrelated siblings.

    Science.gov (United States)

    Segal, N L; Feng, R; McGuire, S A; Allison, D B; Miller, S

    2009-01-01

    Earlier studies have established that a substantial percentage of variance in obesity-related phenotypes is explained by genetic components. However, only one study has used both virtual twins (VTs) and biological twins and was able to simultaneously estimate additive genetic, non-additive genetic, shared environmental and unshared environmental components in body mass index (BMI). Our current goal was to re-estimate four components of variance in BMI, applying a more rigorous model to biological and virtual multiples with additional data. Virtual multiples share the same family environment, offering unique opportunities to estimate common environmental influence on phenotypes that cannot be separated from the non-additive genetic component using only biological multiples. Data included 929 individuals from 164 monozygotic twin pairs, 156 dizygotic twin pairs, five triplet sets, one quadruplet set, 128 VT pairs, two virtual triplet sets and two virtual quadruplet sets. Virtual multiples consist of one biological child (or twins or triplets) plus one same-aged adoptee who are all raised together since infancy. We estimated the additive genetic, non-additive genetic, shared environmental and unshared random components in BMI using a linear mixed model. The analysis was adjusted for age, age(2), age(3), height, height(2), height(3), gender and race. Both non-additive genetic and common environmental contributions were significant in our model (P-valuesrole in BMI and that common environmental factors such as diet or exercise also affect BMI. This conclusion is consistent with our earlier study using a smaller sample and shows the utility of virtual multiples for separating non-additive genetic variance from common environmental variance.

  16. Pathological findings in dicephalus dipus dibrachius: implications for mechanisms in two pairs of lateral conjoined twins.

    Science.gov (United States)

    Itoh, K; Imai, Y; Obayashi, C; Hayashi, Y; Hanioka, K; Itoh, H

    1993-06-01

    The anatomical and pathological features of two pairs of dicephalic conjoined twins (case 1 and 2) are described. Both twins showed duplicitas lateralis representing diprosopus dipus dibrachius. There were two complete heads on two necks, one thorax, one abdomen and externally normal two arms and two legs. Case 1 showed dicephalus with anencephaly, two vertebral columns and two spinal cords, which converged from the thoracic region distally. The esophagus, stomachs and partial small intestines were duplicated, which fused at yolk sac (with Meckel's diverticulum). The heart was incompletely fused. The lungs and trachea were doubled. Two spinal cords were fused from the thoracic region caudally and showed myelomeningocele and Arnold-Chiari malformation in case 2. Two larynxes and two thracheas connected with the incompletely fused three lobes of lungs. The conjoined lungs were hypoplastic. The heart was single, showing ventral septal defect, transposition of great arteries, two cuspid aortic valves and preductal aortic coarctation. The duplicated esophagi were conjoined in Y-shape and single stomach, duodenum, intestine and colon were found. There were pairs of kidneys, adrenal glands and ureters and single female genitalia in both cases. These findings indicate that the craniocaudal paleoaxes were separated in the cranial region and converted or fused under the thoracic region like a Y-shape. Further development defects and deformations might be important factors to form malformations in these case.

  17. Small effect of genetic factors on neck pain in old age: a study of 2,108 Danish twins 70 years of age and older

    DEFF Research Database (Denmark)

    Hartvigsen, Jan; Petersen, Hans Christian; Frederiksen, Henrik

    2005-01-01

    STUDY DESIGN: Classic twin study. OBJECTIVES: To determine the heritability of neck pain in persons 70 years of age and older. SUMMARY OF BACKGROUND DATA: Previous studies have shown a moderate effect of genetic factors on back pain in the elderly. Genetic influence on neck pain in old age...... calculated and compared for monozygotic and dizygotic twins. Further, heritability estimates were calculated using bivariate probit estimation. RESULTS: A total of 2,108 twin individuals, including 1,054 complete twin pairs, answered the question related to neck pain at intake into the Longitudinal Study...... environmental risk factors (rheumatoid arthritis, osteoarthritis, disc prolapse, and coronary heart disease) showed no significant additive genetic, dominant genetic, or common environmental effects. CONCLUSION: Genetic factors do not play an important role in the liability to neck pain in persons 70 years...

  18. The genetic basis for cognitive ability, memory, and depression symptomatology in middle-aged and elderly chinese twins

    DEFF Research Database (Denmark)

    Xu, Chunsheng; Sun, Jianping; Ji, Fuling

    2015-01-01

    The genetic influences on aging-related phenotypes, including cognition and depression, have been well confirmed in the Western populations. We performed the first twin-based analysis on cognitive performance, memory and depression status in middle-aged and elderly Chinese twins, representing...... the world's largest and most rapidly aging population. The sample consisted of 384 twin pairs with a median age of 50 years. Cognitive function was measured using the Montreal Cognitive Assessment (MoCA) scale; memory was assessed using the revised Wechsler Adult Intelligence scale; depression...... with heritability 0.44 for cognition and 0.56 for memory. Multivariate analysis by the reduced Cholesky model estimated significant genetic (rG = 0.69) and unique environmental (rE = 0.25) correlation between cognitive ability and memory. The model also estimated weak but significant inverse genetic correlation...

  19. Differentially Methylated DNA Regions in Monozygotic Twin Pairs Discordant for Rheumatoid Arthritis

    DEFF Research Database (Denmark)

    Svendsen, Anders J; Gervin, Kristina; Lyle, Robert

    2016-01-01

    : Smoking was significantly associated with hypomethylation of a DMR overlapping the promoter region of the RNF5 and the AGPAT1, which are implicated in inflammation and autoimmunity, whereas DMARD treatment induced hypermethylation of the same region. Additionally, the promotor region of both S100A6......OBJECTIVES: In an explorative epigenome-wide association study (EWAS) to search for gene independent, differentially methylated DNA positions and regions (DMRs) associated with rheumatoid arthritis (RA) by studying monozygotic (MZ) twin pairs discordant for RA. METHODS: Genomic DNA was isolated......: We identified several differentially methylated regions associated with RA, which may represent environmental effects or consequences of the disease and plausible biological pathways pertinent to the pathogenesis of RA....

  20. Age-dependent changes in mean and variance of gene expression across tissues in a twin cohort.

    Science.gov (United States)

    Viñuela, Ana; Brown, Andrew A; Buil, Alfonso; Tsai, Pei-Chien; Davies, Matthew N; Bell, Jordana T; Dermitzakis, Emmanouil T; Spector, Timothy D; Small, Kerrin S

    2018-02-15

    Changes in the mean and variance of gene expression with age have consequences for healthy aging and disease development. Age-dependent changes in phenotypic variance have been associated with a decline in regulatory functions leading to increase in disease risk. Here, we investigate age-related mean and variance changes in gene expression measured by RNA-seq of fat, skin, whole blood and derived lymphoblastoid cell lines (LCLs) expression from 855 adult female twins. We see evidence of up to 60% of age effects on transcription levels shared across tissues, and 47% of those on splicing. Using gene expression variance and discordance between genetically identical MZ twin pairs, we identify 137 genes with age-related changes in variance and 42 genes with age-related discordance between co-twins; implying the latter are driven by environmental effects. We identify four eQTLs whose effect on expression is age-dependent (FDR 5%). Combined, these results show a complicated mix of environmental and genetically driven changes in expression with age. Using the twin structure in our data, we show that additive genetic effects explain considerably more of the variance in gene expression than aging, but less that other environmental factors, potentially explaining why reliable expression-derived biomarkers for healthy-aging have proved elusive compared with those derived from methylation. © The Author(s) 2017. Published by Oxford University Press.

  1. Sex differences in the pathways to major depression: a study of opposite-sex twin pairs.

    Science.gov (United States)

    Kendler, Kenneth S; Gardner, Charles O

    2014-04-01

    The authors sought to clarify the nature of sex differences in the etiologic pathways to major depression. Retrospective and prospective assessments of 20 developmentally organized risk factors and the occurrence of past-year major depression were conducted at two waves of personal interviews at least 12 months apart in 1,057 opposite-sex dizygotic twin pairs from a population-based register. Analyses were conducted by structural modeling, examining within-pair differences. Sixty percent of all paths in the best-fit model exhibited sex differences. Eleven of the 20 risk factors differed across sexes in their impact on liability to major depression. Five had a greater impact in women: parental warmth, neuroticism, divorce, social support, and marital satisfaction. Six had a greater impact in men: childhood sexual abuse, conduct disorder, drug abuse, prior history of major depression, and distal and dependent proximal stressful life events. The life event categories responsible for the stronger effect in males were financial, occupational, and legal in nature. In a co-twin control design, which matches sisters and brothers on genetic and familial-environmental background, personality and failures in interpersonal relationships played a stronger etiologic role in major depression for women than for men. Externalizing psychopathology, prior depression, and specific "instrumental" classes of acute stressors were more important in the etiologic pathway to major depression for men. The results are consistent with previously proposed typologies of major depression that suggest two subtypes that differ in prevalence in women (deficiencies in caring relationships and interpersonal loss) and men (failures to achieve expected goals, with lowered self-worth).

  2. Discordant tooth agenesis and peg-shaped in a pair of monozygotic twins: Clinical and molecular study

    Directory of Open Access Journals (Sweden)

    Lívia Azeredo Alves Antunes

    2013-01-01

    Full Text Available The present report aimed to study an uncommon case of a pair of twins that presented a discordant dental phenotype. Family investigation, clinical, radiographic examination and molecular analysis were performed in both girls. Molecular analysis confirmed the monozygosity by deoxyribonucleic acid chip technology. One twin presented tooth agenesis in left upper lateral incisor and peg-shaped on the contra lateral side while the other twin had no dental alterations. The dental casts study employed digital caliper to compare morphological dimensions and showed alteration only in peg-shaped tooth. In conclusion, this study provide support that one or more mutated gene could cause discordances in dental phenotype in these monozygotic twins.

  3. Heritability and Genome-Wide Association Analyses of Serum Uric Acid in Middle and Old-Aged Chinese Twins

    DEFF Research Database (Denmark)

    Wang, Weijing; Zhang, Dongfeng; Xu, Chunsheng

    2018-01-01

    Serum uric acid (SUA), as the end product of purine metabolism, has proven emerging roles in human disorders. Here based on a sample of 379 middle and old-aged Chinese twin pairs, we aimed to explore the magnitude of genetic impact on SUA variation by performing sex-limitation twin modeling analy...... involved in functional genes and regulatory domains that mediate SUA level. Our findings provide clues to further elucidate molecular physiology of SUA homeostasis and identify new diagnostic biomarkers and therapeutic targets for hyperuricemia and gout....

  4. Marital status and twins' health and behavior: an analysis of middle-aged Danish twins

    DEFF Research Database (Denmark)

    Osler, Merete; McGue, Matt; Lund, Rikke

    2008-01-01

    mass index (BMI), depression symptoms, self-rated health, cognitive function, physical activity, smoking, and alcohol intake. RESULTS: Among all 2350 individual twins, men who were divorced/widowed or never married had higher depression scores, lower cognitive test scores, lower physical activity....../widowed twin had higher average depression scores and was more likely to be a smoker. Never married twins had lower physical activity scores and never married male twins had higher BMI and higher depression scores than their married co-twin. CONCLUSION: This study suggests that the relationships of adult...... divorce with depression and smoking in Danish twins are due to the stressful effects of marital dissolution, but that marital differences in other health and behavioral outcomes are most consistent with selection effects related to genetic or rearing environmental factors....

  5. Genetic influences on exercise participation in 37,051 twin pairs from seven countries.

    Directory of Open Access Journals (Sweden)

    Janine H Stubbe

    2006-12-01

    Full Text Available A sedentary lifestyle remains a major threat to health in contemporary societies. To get more insight in the relative contribution of genetic and environmental influences on individual differences in exercise participation, twin samples from seven countries participating in the GenomEUtwin project were used.Self-reported data on leisure time exercise behavior from Australia, Denmark, Finland, Norway, The Netherlands, Sweden and United Kingdom were used to create a comparable index of exercise participation in each country (60 minutes weekly at a minimum intensity of four metabolic equivalents.Modest geographical variation in exercise participation was revealed in 85,198 subjects, aged 19-40 years. Modeling of monozygotic and dizygotic twin resemblance showed that genetic effects play an important role in explaining individual differences in exercise participation in each country. Shared environmental effects played no role except for Norwegian males. Heritability of exercise participation in males and females was similar and ranged from 48% to 71% (excluding Norwegian males.Genetic variation is important in individual exercise behavior and may involve genes influencing the acute mood effects of exercise, high exercise ability, high weight loss ability, and personality. This collaborative study suggests that attempts to find genes influencing exercise participation can pool exercise data across multiple countries and different instruments.

  6. Birth weight centiles by gestational age for twins born in south India.

    Science.gov (United States)

    Premkumar, Prasanna; Antonisamy, Belavendra; Mathews, Jiji; Benjamin, Santhosh; Regi, Annie; Jose, Ruby; Kuruvilla, Anil; Mathai, Mathews

    2016-03-24

    Birth weight centile curves are commonly used as a screening tool and to assess the position of a newborn on a given reference distribution. Birth weight of twins are known to be less than those of comparable singletons and twin-specific birth weight centile curves are recommended for use. In this study, we aim to construct gestational age specific birth weight centile curves for twins born in south India. The study was conducted at the Christian Medical College, Vellore, south India. The birth records of all consecutive pregnancies resulting in twin births between 1991 and 2005 were reviewed. Only live twin births between 24 and 42 weeks of gestation were included. Birth weight centiles for gestational age were obtained using the methodology of generalized additive models for location, scale and shape (GAMLSS). Centiles curves were obtained separately for monochorionic and dichorionic twins. Of 1530 twin pregnancies delivered during the study period (1991-2005), 1304 were included in the analysis. The median gestational age at birth was 36 weeks (1st quartile 34, 3rd quartile 38 weeks). Smoothed percentile curves for birth weight by gestational age increased progressively till 38 weeks and levels off thereafter. Compared with dichorionic twins, monochorionic twins had lower birth weight for gestational age from after 27 weeks. We provide centile values of birth weight at 24 to 42 completed weeks of gestation for twins born in south India. These charts could be used both in routine clinical assessments and epidemiological studies.

  7. Twin RSA

    OpenAIRE

    Lenstra, Arjen K.; Weger, De; Benjamin, M. M.

    2005-01-01

    We introduce Twin RSA, pairs of RSA moduli (n, n+ 2), and formulate several questions related to it. Our main questions are: is Twin RSA secure, and what is it good for? © Springer-Verlag Berlin Heidelberg 2005.

  8. Ischiopagus and diprosopus in India: two pairs of conjoined twins perceived as incarnations of Hindu deities.

    Science.gov (United States)

    Tubbs, R Shane; Ditty, Benjamin; Bosmia, Anand N; Bosmia, Arpan N

    2015-02-01

    This article briefly reviews two specific types of conjoined twins, ischiopagus and diprosopus, and discusses recent cases of such twins born in India. Some members of the Hindu community worshiped these conjoined twins as incarnations of Hindu deities. In discussing this phenomenon, the authors aim to elucidate certain features of the faith tradition of Hinduism itself. The reception of these conjoined twins as incarnations of Hindu deities can be understood by examining two salient features of Hindu polytheism: the pictorial depiction of Hindu deities with multiple appendages and the concept of an incarnation, or avatar, of a Hindu deity.

  9. The morphology of the sella turcica in monozygotic twins

    DEFF Research Database (Denmark)

    Brock-Jacobsen, Mette T; Pallisgaard, Carsten; Kjaer, Inger

    2009-01-01

    of 42 twin pairs (18 male and 24 female pairs, aged 18-23 years) comprised the material. Sella turcica measurements from non-twins aged 6-21 years were used as normal reference. Length, depth and diameter of the sella turcica were measured and controlled by re-measurements. Pearson's correlation...... showed that the size of the sella turcica may be partly similar and partly dissimilar within the pair of monozygotic twins. Statistical evaluation of the data showed correlations between length, depth and diameter of the sella turcica between the two twin individuals in the same twin pair. Differences...

  10. Aging Trajectories in Different Body Systems Share Common Environmental Etiology : The Healthy Aging Twin Study (HATS)

    NARCIS (Netherlands)

    Moayyeri, Alireza; Hart, Deborah J.; Snieder, Harold; Hammond, Christopher J.; Spector, Timothy D.; Steves, Claire J.

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal

  11. Nuchal translucency measurements are highly correlated in both mono- and dichorionic twin pairs

    DEFF Research Database (Denmark)

    Wøjdemann, Karen R; Larsen, Severin Olesen; Shalmi, Anne-Cathrine

    2006-01-01

    OBJECTIVES: To establish the distribution of serological and ultrasound first-trimester Down syndrome markers in twins and identify correlations of significance for risk calculation. METHODS: Nuchal translucency (NT), PAPP-A and betahCG data were extracted from 181 twin pregnancies (31 mono- and ...

  12. Autopsy Findings on a Pair of Dicephalic Parapagus Twins: A Case ...

    African Journals Online (AJOL)

    Conjoined twins are a rare occurrence that presents significant challenges to both parents and medical care givers with many theories being advanced to explain this occurrence.“Parapagus” is a fairly recent term, in which the twins lie side by side with ventro-lateral fusion and are extremely rare representing 0.5% of all ...

  13. Exploring Subclinical Phenotypic Features in Twin Pairs Discordant for Cleft Lip and Palate

    DEFF Research Database (Denmark)

    Leslie, Elizabeth J; Carlson, Jenna C; Cooper, Margaret E

    2017-01-01

    OBJECTIVE: Monozygotic twins of an individual with an orofacial cleft have a significantly elevated risk for orofacial cleft compared with the general population, but still the concordance rate for orofacial cleft in monozygotic twins is about 40% to 50%. The goal of this study was to determine w...

  14. The genetic basis for cognitive ability, memory, and depression symptomatology in middle-aged and elderly chinese twins.

    Science.gov (United States)

    Xu, Chunsheng; Sun, Jianping; Ji, Fuling; Tian, Xiaocao; Duan, Haiping; Zhai, Yaoming; Wang, Shaojie; Pang, Zengchang; Zhang, Dongfeng; Zhao, Zhongtang; Li, Shuxia; Hjelmborg, Jacob V B; Christensen, Kaare; Tan, Qihua

    2015-02-01

    The genetic influences on aging-related phenotypes, including cognition and depression, have been well confirmed in the Western populations. We performed the first twin-based analysis on cognitive performance, memory and depression status in middle-aged and elderly Chinese twins, representing the world's largest and most rapidly aging population. The sample consisted of 384 twin pairs with a median age of 50 years. Cognitive function was measured using the Montreal Cognitive Assessment (MoCA) scale; memory was assessed using the revised Wechsler Adult Intelligence scale; depression symptomatology was evaluated by the self-reported 30-item Geriatric Depression (GDS-30)scale. Both univariate and multivariate twin models were fitted to the three phenotypes with full and nested models and compared to select the best fitting models. Univariate analysis showed moderate-to-high genetic influences with heritability 0.44 for cognition and 0.56 for memory. Multivariate analysis by the reduced Cholesky model estimated significant genetic (rG = 0.69) and unique environmental (rE = 0.25) correlation between cognitive ability and memory. The model also estimated weak but significant inverse genetic correlation for depression with cognition (-0.31) and memory (-0.28). No significant unique environmental correlation was found for depression with other two phenotypes. In conclusion, there can be a common genetic architecture for cognitive ability and memory that weakly correlates with depression symptomatology, but in the opposite direction.

  15. Vanishing twins: a predictor of small-for-gestational age in IVF singletons

    DEFF Research Database (Denmark)

    Pinborg, Anja; Lidegaard, Ojvind; Freiesleben, Nina la Cour

    2007-01-01

    The purpose of this study was to assess the effect of a vanishing twin on the risk of being small-for-gestational age (SGA) in in vitro fertilization (IVF) singletons.......The purpose of this study was to assess the effect of a vanishing twin on the risk of being small-for-gestational age (SGA) in in vitro fertilization (IVF) singletons....

  16. The rate of nonallelic homologous recombination in males is highly variable, correlated between monozygotic twins and independent of age.

    Directory of Open Access Journals (Sweden)

    Jacqueline A L MacArthur

    2014-03-01

    Full Text Available Nonallelic homologous recombination (NAHR between highly similar duplicated sequences generates chromosomal deletions, duplications and inversions, which can cause diverse genetic disorders. Little is known about interindividual variation in NAHR rates and the factors that influence this. We estimated the rate of deletion at the CMT1A-REP NAHR hotspot in sperm DNA from 34 male donors, including 16 monozygotic (MZ co-twins (8 twin pairs aged 24 to 67 years old. The average NAHR rate was 3.5 × 10(-5 with a seven-fold variation across individuals. Despite good statistical power to detect even a subtle correlation, we observed no relationship between age of unrelated individuals and the rate of NAHR in their sperm, likely reflecting the meiotic-specific origin of these events. We then estimated the heritability of deletion rate by calculating the intraclass correlation (ICC within MZ co-twins, revealing a significant correlation between MZ co-twins (ICC = 0.784, p = 0.0039, with MZ co-twins being significantly more correlated than unrelated pairs. We showed that this heritability cannot be explained by variation in PRDM9, a known regulator of NAHR, or variation within the NAHR hotspot itself. We also did not detect any correlation between Body Mass Index (BMI, smoking status or alcohol intake and rate of NAHR. Our results suggest that other, as yet unidentified, genetic or environmental factors play a significant role in the regulation of NAHR and are responsible for the extensive variation in the population for the probability of fathering a child with a genomic disorder resulting from a pathogenic deletion.

  17. Genetic influences on exercise participation in 37.051 twin pairs from seven countries.

    NARCIS (Netherlands)

    Stubbe, J.H.; Boomsma, D.I.; Vink, J.M.; Cornes, B.; Martin, N.G.; Skytthe, A.; Kyvik, K.; Rose, R.J.; Kujala, U.; Kaprio, J.; Harris, J.R.; Pedersen, N.L.; Hunkin, J.; Spector, T.D.; de Geus, E.J.C.

    2006-01-01

    Background. A sedentary lifestyle remains a major threat to health in contemporary societies. To get more insight in the relative contribution of genetic and environmental influences on individual differences in exercise participation, twin samples from seven countries participating in the

  18. Respiratory morbidity in twins by birth order, gestational age and mode of delivery.

    Science.gov (United States)

    Bricelj, Katja; Tul, Natasa; Lasic, Mateja; Bregar, Andreja Trojner; Verdenik, Ivan; Lucovnik, Miha; Blickstein, Isaac

    2016-10-01

    To evaluate the relationship between respiratory morbidity in twins by gestational age, birth order and mode of delivery. All twin deliveries at birth order and to the mode of delivery. In contrast, RDS was more frequent among the second born twins in the vaginal birth groups born at 30-36 weeks [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.2-5.1 and OR 2.0, 95% CI 1.2-3.5 for 33-36 weeks and 30-32 weeks, respectively], whereas this trend was seen in the cesarean birth groups born earlier (OR 3.8, 95% CI 1.1-13.0 for 28-29 weeks). Cesarean delivery significantly increased the frequency of RDS in twin A as well as in twin B compared with vaginal birth, but only at gestational ages birth order have a gestational age dependent effect on the incidence of RDS.

  19. Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age

    DEFF Research Database (Denmark)

    Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo

    2015-01-01

    A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins...

  20. Basic Research on A-bomb exposed and nonexposed pair of twins and the pilot case study from socio-psycho-historical viewpoint

    International Nuclear Information System (INIS)

    Watanabe, Shoji; Satow, Yukio; Okamoto, Naomasa

    1980-01-01

    A-bomb exposed and nonexposed pair monozygotic twins were investigated. In all the cases, a pair of twins had great similarity in appearance and were connected firmly each other from their childhood. In family relations, each of them was required to take a role as the younger or the elder. Interview and psychological test suggested some psychological trauma in the exposed one compared with the other nonexposed. The mental state of the exposed is little understood even by the other half of twins who are in close relation. (Ueda, J.)

  1. Moderation of genetic and environmental influences on diurnal preference by age in adult twins.

    Science.gov (United States)

    Barclay, Nicola L; Watson, Nathaniel F; Buchwald, Dedra; Goldberg, Jack

    2014-03-01

    Diurnal preference changes across the lifespan. However, the mechanisms underlying this age-related shift are poorly understood. The aim of this twin study was to determine the extent to which genetic and environmental influences on diurnal preference are moderated by age. Seven hundred and sixty-eight monozygotic and 674 dizygotic adult twin pairs participating in the University of Washington Twin Registry completed the reduced Morningness-Eveningness Questionnaire as a measure of diurnal preference. Participants ranged in age from 19 to 93 years (mean = 36.23, SD = 15.54) and were categorized on the basis of age into three groups: younger adulthood (19-35 years, n = 1715 individuals), middle adulthood (36-64 years, n = 1003 individuals) and older adulthood (65+ years, n = 168 individuals). Increasing age was associated with an increasing tendency towards morningness (r = 0.42, p influences for the total sample as well as for each age group separately. Additive genetic influences accounted for 52%[46-57%], and non-shared environmental influences 48%[43-54%], of the total variance in diurnal preference. In comparing univariate genetic models between age groups, the best-fitting model was one in which the parameter estimates for younger adults and older adults were equated, in comparison with middle adulthood. For younger and older adulthood, additive genetic influences accounted for 44%[31-49%] and non-shared environmental influences 56%[49-64%] of variance in diurnal preference, whereas for middle adulthood these estimates were 34%[21-45%] and 66%[55-79%], respectively. Therefore, genetic influences on diurnal preference are attenuated in middle adulthood. Attenuation is likely driven by the increased importance of work and family responsibilities during this life stage, in comparison with younger and older adulthood when these factors may be less influential in determining sleep-wake timing. These findings have implications for studies

  2. Do very preterm twins and singletons differ in their neurodevelopment at 5 years of age?

    Science.gov (United States)

    Bodeau-Livinec, Florence; Zeitlin, Jennifer; Blondel, Béatrice; Arnaud, Catherine; Fresson, Jeanne; Burguet, Antoine; Subtil, Damien; Marret, Stéphane; Rozé, Jean-Christophe; Marchand-Martin, Laetitia; Ancel, Pierre-Yves; Kaminski, Monique

    2013-11-01

    Twins have inconsistently shown poorer outcomes than singletons. Although a high proportion of twins are born very preterm, data are sparse on the long-term outcomes in very preterm twins. The objective of this study was to compare mortality and neurodevelopmental outcomes of very preterm singletons and twins and to study outcomes in relation to factors specific to twins. Birth cohort study Etude Epidemiologique sur les Petits Ages Gestationnels (EPIPAGE). Nine regions in France. All very preterm live births occurring from 22 to 32 weeks of gestation in all maternity wards of nine French regions in 1997 (n=2773). Neurodevelopmental status, including cerebral palsy, and a cognitive assessment with the Kaufman Assessment Battery for Children, with scores on the Mental Processing Composite (MPC) scale, was available for 1732 and 1473 children at 5 years of age, respectively. Among live births, twins had higher hospital mortality than singletons (adjusted (a)OR: 1.4 (95% CI 1.1 to 1.9)). Among survivors, there was no crude difference at 5 years between twins and singletons in the prevalence of cerebral palsy (8.0% vs 9.1%, respectively), MPC <70 (9.5% vs 11.1%) and mean MPC (94.6 vs 94.4). However, after adjustment for sex, gestational age, intrauterine growth restriction and social factors, twins were more likely to have lower MPC scores (mean difference: -2.4 (95% CI-4.8 to 0.01)). Live born twins had a higher risk of mortality when birth weight discordance was present (aOR:2.9 (95% CI 1.7 to 4.8)), but there were no differences in long-term outcomes. Compared with very preterm singletons, twins had higher mortality, no difference with respect to severe deficiencies, but slightly lower MPC scores at 5 years.

  3. Functional and effective whole brain connectivity using magnetoencephalography to identify monozygotic twin pairs

    NARCIS (Netherlands)

    Demuru, M.; Gouw, A.; Hillebrand, A.; Stam, C J; van Dijk, B W; Scheltens, P.; Tijms, B.M.; Konijnenberg, E.; ten Kate-Booij, M.J.; den Braber, A; Smit, D J A; Boomsma, D I; Visser, P J

    2017-01-01

    Resting-state functional connectivity patterns are highly stable over time within subjects. This suggests that such 'functional fingerprints' may have strong genetic component. We investigated whether the functional (FC) or effective (EC) connectivity patterns of one monozygotic twin could be used

  4. Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project.

    Science.gov (United States)

    Yokoyama, Yoshie; Jelenkovic, Aline; Sund, Reijo; Sung, Joohon; Hopper, John L; Ooki, Syuichi; Heikkilä, Kauko; Aaltonen, Sari; Tarnoki, Adam D; Tarnoki, David L; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos C E M; Saudino, Kimberly J; Cutler, Tessa L; Nelson, Tracy L; Whitfield, Keith E; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; He, Mingguang; Ding, Xiaohu; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Jeong, Hoe-Uk; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Burt, S Alexandra; Klump, Kelly L; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas Sevenius; Craig, Jeffrey M; Saffery, Richard; Ji, Fuling; Ning, Feng; Pang, Zengchang; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Tynelius, Per; Haworth, Claire M A; Plomin, Robert; Rebato, Esther; Rose, Richard J; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko; Silventoinen, Karri

    2016-04-01

    We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.

  5. Relationship between 17-hydroxyprogesterone caproate concentrations and gestational age at delivery in twin gestation.

    LENUS (Irish Health Repository)

    Caritis, Steve N

    2012-11-01

    We sought to evaluate in women with twin gestation the relationship between 17-hydroxyprogesterone caproate (17-OHPC) concentration and gestational age at delivery and select biomarkers of potential pathways of drug action.

  6. The nature of behavioural correlates of healthy ageing: a twin study of lifestyle in mid to late life.

    Science.gov (United States)

    McGue, Matt; Skytthe, Axel; Christensen, Kaare

    2014-06-01

    With the greying of the industrialized world has come increased interest in identifying the modifiable lifestyle factors that promote healthy and successful ageing. Whereas many of the behavioural correlates of late-life morbidity and mortality have been identified, relatively little is known about the origins of individual differences in these factors. A sample of 12,714 twins, including both members of 3806 pairs of known zygosity, ascertained through the Danish Twin Registry and aged 40 to 80 years, completed a self-report assessment of six lifestyle factors associated with ageing: smoking, drinking, diet and physical, social and intellectual activities. Standard biometric methods were used to analyse the twin data and determine the extent to which individual differences in each of the lifestyle factors are heritable. For each of the six lifestyle factors, the estimate of heritability ranged from 32% (95% CI: 19-42%) for the diet scale to 69% (62-72%) for the smoking measure. Biometric estimates of the contribution of the twins' common rearing environment were uniformly small (≤6%). There was little evidence that standardized biometric estimates varied by gender or age. Individuals likely construct lifestyles in part to complement and reinforce underlying genetically influenced dispositions and talents. The heritable nature of lifestyle factors implies that the behavioural and genetic contributors to ageing processes are not necessarily conceptually distinct but rather reflect the complexity of gene-environment interplay in ageing. Published by Oxford University Press on behalf of the International Epidemiological Association © The Author 2014; all rights reserved.

  7. DNA methylation age is associated with mortality in a longitudinal Danish twin study

    DEFF Research Database (Denmark)

    Christiansen, Lene; Lenart, Adam; Tan, Qihua

    2016-01-01

    included a 10-year longitudinal study of the 86 oldest-old twins (mean age of 86.1 at follow-up), which subsequently were followed for mortality for 8 years. We found that the DNAm age is highly correlated with chronological age across all age groups (r = 0.97), but that the rate of change of DNAm age...

  8. Investigating Unique Environmental Influences of Parenting Practices on Youth Anxiety: A Monozygotic Twin Differences Study

    Science.gov (United States)

    Chen, Jie; Yu, Jing; Zhang, Jianxin

    2016-01-01

    The associations between parenting practices and adolescent anxiety symptoms were examined in both individual and monozygotic (MZ) twin differences levels. Participants were 804 pairs of Chinese MZ adolescent twins aged 10-18 years (M = 13.57, SD = 2.67, 52% females). Twins' anxiety symptoms were assessed by self- and parent-reports. Twins also…

  9. Heritability of resting heart rate and association with mortality in middle-aged and elderly twins

    DEFF Research Database (Denmark)

    Jensen, Magnus T; Wod, Mette; Galatius, Søren

    2018-01-01

    , heritability estimates were 0.23 (95% CI 0.15 to 0.30); 0.27 (0.15 to 0.38) for males and 0.17 (0.06 to 0.28) for females. In multivariable models adjusting for age, gender, body mass index, diabetes, hypertension, pulmonary function, smoking, physical activity and zygosity, RHR was significantly associated......OBJECTIVE: Resting heart rate (RHR) possibly has a hereditary component and is associated with longevity. We used the classical biometric twin study design to investigate the heritability of RHR in a population of middle-aged and elderly twins and, furthermore, studied the association between RHR...... in RHR. CONCLUSIONS: RHR is a trait with a genetic influence in middle-aged and elderly twins free of cardiovascular disease. RHR is independently associated with longevity even when familial factors are controlled for in a twin design....

  10. The Qingdao Twin Registry

    DEFF Research Database (Denmark)

    Duan, Haiping; Ning, Feng; Zhang, Dongfeng

    2013-01-01

    In 1998, the Qingdao Twin Registry was initiated as the main part of the Chinese National Twin Registry. By 2005, a total of 10,655 twin pairs had been recruited. Since then new twin cohorts have been sampled, with one longitudinal cohort of adolescent twins selected to explore determinants of me...

  11. Twins and non-twin siblings: different estimates of shared environmental influence in early childhood.

    Science.gov (United States)

    Koeppen-Schomerus, Gesina; Spinath, Frank M; Plomin, Robert

    2003-04-01

    Twin studies typically indicate shared environmental influence for cognitive abilities, especially in early childhood. However, across studies, DZ twin correlations tend to be greater than non-twin sibling correlations, suggesting that twin estimates of shared environment are to some extent specific to twins. We tested this hypothesis in a sample of more than 1800 MZ and 1800 same-sex DZ pairs from the Twins Early Development Study (TEDS), a study of twins born in England and Wales in 1994 and 1995. For this analysis, we obtained comparable data from more than 130 same-sex younger siblings of the twins. Twins and their younger siblings were assessed for language, cognitive abilities and behavior problems by their parents at 2 and 3 years of age. For language and cognitive measures at both 2 and 3 years, but not for behavior problems, estimates of shared environment were more than twice as large for twins as compared to non-twin siblings. We conclude that about half of twin study estimates of shared environment for cognitive abilities in early childhood are specific to twins. Although many possibilities exist for explaining the special shared environment effect for twins, we suggest that cognitive-relevant experiences that are not shared by siblings are shared by twins because they are exactly the same age.

  12. Using Twins to Better Understand Sibling Relationships.

    Science.gov (United States)

    Mark, Katharine M; Pike, Alison; Latham, Rachel M; Oliver, Bonamy R

    2017-03-01

    We compared the nature of the sibling relationship in dyads of varying genetic relatedness, employing a behavioural genetic design to estimate the contribution that genes and the environment have on this familial bond. Two samples were used-the Sisters and Brothers Study consisted of 173 families with two target non-twin children (mean ages = 7.42 and 5.22 years respectively); and the Twins, Family and Behaviour study included 234 families with two target twin children (mean age = 4.70 years). Mothers and fathers reported on their children's relationship with each other, via a postal questionnaire (the Sisters and Brothers Study) or a telephone interview (the Twins, Family and Behaviour study). Contrary to expectations, no mean level differences emerged when monozygotic twin pairs, dizygotic twin pairs, and non-twin pairs were compared on their sibling relationship quality. Behavioural genetic analyses also revealed that the sibling bond was modestly to moderately influenced by the genetic propensities of the children within the dyad, and moderately to substantially influenced by the shared environment common to both siblings. In addition, for sibling negativity, we found evidence of twin-specific environmental influence-dizygotic twins showed more reciprocity than did non-twins. Our findings have repercussions for the broader application of results from future twin-based investigations.

  13. Heritability of psoriasis in a large twin sample

    DEFF Research Database (Denmark)

    Lønnberg, Ann Sophie; Skov, Liselotte; Skytthe, A

    2013-01-01

    AIM: To study the concordance of psoriasis in a population-based twin sample. METHODS: Data on psoriasis in 10,725 twin pairs, 20-71 years of age, from the Danish Twin Registry was collected via a questionnaire survey. The concordance and heritability of psoriasis were estimated. RESULTS: In total...

  14. Does Learning to Read Improve Intelligence? A Longitudinal Multivariate Analysis in Identical Twins from Age 7 to 16

    Science.gov (United States)

    Ritchie, Stuart J.; Bates, Timothy C.; Plomin, Robert

    2015-01-01

    Evidence from twin studies points to substantial environmental influences on intelligence, but the specifics of this influence are unclear. This study examined one developmental process that potentially causes intelligence differences: learning to read. In 1,890 twin pairs tested at 7, 9, 10, 12, and 16 years, a cross-lagged…

  15. Evidences of extragalactic origin and planet engulfment in the metal-poor twin pair HD 134439/HD 134440

    Science.gov (United States)

    Reggiani, Henrique; Meléndez, Jorge

    2018-04-01

    Recent studies of chemical abundances in metal-poor halo stars show the existence of different populations, which is important for studies of Galaxy formation and evolution. Here, we revisit the twin pair of chemically anomalous stars HD 134439 and HD 134440, using high resolution (R ˜ 72 000) and high S/N ratio (S/N ˜ 250) HDS/Subaru spectra. We compare them to the well-studied halo star HD 103095, using the line-by-line differential technique to estimate precise stellar parameters and LTE chemical abundances. We present the abundances of C, O, Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Ba, La, Ce, Nd, and Sm. We compare our results to the precise abundance patterns of Nissen & Schuster (2010) and data from dwarf Spheroidal galaxies (dSphs). We show that the abundance pattern of these stars appears to be closely linked to that of dSphs with [α/Fe] knee below [Fe/H] < -1.5. We also find a systematic difference of 0.06 ± 0.01 dex between the abundances of these twin binary stars, which could be explained by the engulfment of a planet, thus suggesting that planet formation is possible at low metallicities ([Fe/H] = -1.4).

  16. Absence of Substantial Copy Number Differences in a Pair of Monozygotic Twins Discordant for Features of Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Marina Laplana

    2014-01-01

    Full Text Available Autism spectrum disorder (ASD is a highly heritable disease (~0.9 with a complex genetic etiology. It is initially characterized by altered cognitive ability which commonly includes impaired language and communication skills as well as fundamental deficits in social interaction. Despite the large amount of studies described so far, the high clinical diversity affecting the autism phenotype remains poorly explained. Recent studies suggest that rare genomic variations, in particular copy number variation (CNV, may account for a significant proportion of the genetic basis of ASD. The use of disease-discordant monozygotic twins represents a powerful strategy to identify de novo and inherited CNV in the disorder. Here we present the results of a comparative genome hybridization (CGH analysis with a pair of monozygotic twins affected of ASD with significant differences in their clinical manifestations that specially affect speech language impairment and communication skills. Array CGH was performed in three different tissues: blood, saliva, and hair follicle, in an attempt to identify germinal and somatic CNV regions that may explain these differences. Our results argue against a role of large CNV rearrangements as a molecular etiology of the observed differences. This forwards future research to explore de novo point mutation and epigenomic alterations as potential explanations of the observed clinical differences.

  17. [Adult twins].

    Science.gov (United States)

    Charlemaine, Christiane

    2006-12-31

    This paper explores the deep roots of closeness that twins share in their youngest age and their effect on their destiny at the adult age. Psychologists believe the bond between twins begins in utero and develops throughout the twins' lives. The four patterns of twinship described show that the twin bond is determined by the quality of parenting that twins receive in their infancy and early childhood. Common problems of adult twins bring about difficulties to adapt in a non-twin world. The nature versus nurture controversy has taken on new life focusing on inter-twin differences and the importance of parent-child interaction as fundamental to the growth and development of personality.

  18. Sleep Terrors in Twins

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2008-12-01

    Full Text Available In an attempt to clarify the genetic and environmental causes of sleep terrors in childhood, reasearchers in Canada followed 390 pairs of monozygotic and dizygotic twins by assessing the frequency of sleep terrors at 18 and 30 months of age using a questionnaire administered to the biological mothers.

  19. Sleep Terrors in Twins

    OpenAIRE

    J Gordon Millichap

    2008-01-01

    In an attempt to clarify the genetic and environmental causes of sleep terrors in childhood, reasearchers in Canada followed 390 pairs of monozygotic and dizygotic twins by assessing the frequency of sleep terrors at 18 and 30 months of age using a questionnaire administered to the biological mothers.

  20. Neonatal status of twins

    Directory of Open Access Journals (Sweden)

    Božinović Dragica

    2012-01-01

    Full Text Available Multiple pregnancy is a pregnancy where more than one fetus develops simultaneously in the womb, as a result of the ovulation and fertilization of more than one egg. It is relatively rare in humans and represents the rest of the phylogenetic stages. The most common are twins and they indicate the development of two fetuses in the womb. The frequency of twin pregnancies is about 1%. Multiple pregnancies belong to a group of high-risk pregnancies because of the many complications that occur during the pregnancy: higher number of premature deliveries, bleeding, early neonatal complications and higher perinatal morbidity and mortality. Such pregnancies and infants require greater supervision and monitoring. The aim of this study was to determine the percentage of baby twins born at the maternity ward of the General Hospital in Prokuplje and their morbidity and mortality. Data on the total number of deliveries, number of twins, parity and maternal age, gestational age, body weight of twins, method of delivery, Apgar score and perinatal mortality were collected and statistically analyzed by means of retrospective analysis of operative birth and neonatal protocol for 6 years (2005 of 2010. Out of 4527 mothers who gave birth 43 were pairs of twins, or 0.95% of women gave birth to twins. These babies are more likely born by Caesarean section, but delivered with slightly lower birth weight.

  1. Kinetics of 3H-serotonin uptake by platelets in infantile autism and developmental language disorder (including five pairs of twins)

    International Nuclear Information System (INIS)

    Katsui, T.; Okuda, M.; Usuda, S.; Koizumi, T.

    1986-01-01

    The kinetics of 5-HT uptake by platelets was studied in cases of infantile autism and developmental language disorder (DLD) and normal subjects. Two patients of the autism group were twins, and the seven patients of the DLD group were members of four pairs of twins. The Vmax values (means +/- SD) for autism and DLD were 6.46 +/- .90 pmol 5-HT/10(7) cells/min and 4.85 +/- 1.50 pmol 5-HT/10(7) cells/min, respectively. These values were both significantly higher than that of 2.25 +/- .97 pmole 5-HT/10(7) cells/min for normal children. The Km values of the three groups were not significantly different. Data on the five pairs of twins examined suggested that the elevated Vmax of 5-HT uptake by platelets was determined genetically

  2. Aggregation of thyroid autoantibodies in twins from opposite-sex pairs suggests that microchimerism may play a role in the early stages of thyroid autoimmunity

    DEFF Research Database (Denmark)

    Brix, Thomas Heiberg; Hansen, Pia Skov; Kyvik, Kirsten Ohm

    2009-01-01

    to play a role in the pathogenesis of thyroid autoimmunity. In that case, twins from opposite-sex pairs (OS) should have an increased risk of thyroid autoantibodies (TA). AIM: The aim of the study was to compare the frequency of TA in twin individuals from OS and monozygotic (MZ) twin pairs. Design...... positive if greater than 60 U/ml, greater than 60 U/ml, and greater than 1.0 U/liter, respectively. RESULTS: The frequency of TPOAb, TgAb, and TSHRAb among female cases was 15.0, 5.0, and 4.2%, respectively, which was higher than the corresponding prevalences in the female control population: 7.4% (P = 0...

  3. Kinetics of 3H-serotonin uptake by platelets in infantile autism and developmental language disorder (including five pairs of twins)

    Energy Technology Data Exchange (ETDEWEB)

    Katsui, T.; Okuda, M.; Usuda, S.; Koizumi, T.

    1986-03-01

    The kinetics of 5-HT uptake by platelets was studied in cases of infantile autism and developmental language disorder (DLD) and normal subjects. Two patients of the autism group were twins, and the seven patients of the DLD group were members of four pairs of twins. The Vmax values (means +/- SD) for autism and DLD were 6.46 +/- .90 pmol 5-HT/10(7) cells/min and 4.85 +/- 1.50 pmol 5-HT/10(7) cells/min, respectively. These values were both significantly higher than that of 2.25 +/- .97 pmole 5-HT/10(7) cells/min for normal children. The Km values of the three groups were not significantly different. Data on the five pairs of twins examined suggested that the elevated Vmax of 5-HT uptake by platelets was determined genetically.

  4. Heritability of the Number of Teeth in Middle-Aged and Older Danish Twins

    DEFF Research Database (Denmark)

    Kurushima, Y; Silventoinen, K; Dokkedal, U

    2017-01-01

    Tooth loss is a common health concern in older adults. We aimed to estimate the relative contributions of genetic and environmental factors to the variation in the number of teeth in middle-aged and older populations using a population-based cohort of Danish twins. The study included 5,269 Danish...

  5. Epigenome-Wide Association Study of Cognitive Functioning in Middle-Aged Monozygotic Twins

    DEFF Research Database (Denmark)

    Starnawska, Anna; Tan, Qihua; McGue, Matt

    2017-01-01

    As the world's population ages, the age-related cognitive decline presents a great challenge to world's healthcare systems. One of the molecular mechanisms implicated in cognitive ageing is DNA methylation, an epigenetic modification known to be a key player in memory formation, maintenance......, and synaptic plasticity. Using the twin design we performed an epigenome-wide association study (EWAS) in a population of 486 middle-aged monozygotic twins (mean age at follow-up 65.9, SD = 6.1) and correlated their blood DNA methylation to their level (cross-sectional analysis) and change in cognitive...... abilities over 10 years (longitudinal analysis). We identified several CpG sites where cross-sectional cognitive functioning was associated with DNA methylation levels. The top identified loci were located in ZBTB46 (p = 5.84 × 10-7), and TAF12 (p = 4.91 × 10-7). KEGG's enrichment analyses of the most...

  6. Heritability of the Number of Teeth in Middle-Aged and Older Danish Twins.

    Science.gov (United States)

    Kurushima, Y; Silventoinen, K; Dokkedal, U; Skytthe, A; Mucci, L A; Christensen, K; Hjelmborg, J V B

    2017-12-01

    Tooth loss is a common health concern in older adults. We aimed to estimate the relative contributions of genetic and environmental factors to the variation in the number of teeth in middle-aged and older populations using a population-based cohort of Danish twins. The study included 5,269 Danish middle-aged or older twins who provided data on the number of teeth at baseline by structured interviews. The data were analyzed using univariate liability threshold modeling, stratified by sex and age, to estimate familial risk of tooth loss as well as estimates of heritability. In the whole cohorts, 23% of participants were edentate and 53% had retained 20 or more teeth. A statistical model including additive genetic factors and environmental factors partly shared by co-twins and partly unique to each individual twin gave the best statistical fit for the number of teeth in both age categories as well as in men and women. Overall, additive genetic factors explained 36% (95% confidence interval [CI]: 23% to 49%), common environmental factors 20% (95% CI: 9% to 31%), and unique environmental factors 44% (95% CI: 40% to 48%) of the total variation of the number of teeth. This study indicates that a substantial part of the variation in tooth loss is explained by genetic as well as environmental factors shared by co-twins. Our results implied that family background importantly affects tooth loss in both the middle-aged and the older populations. Family history is thus an important factor to take into account in dental health care.

  7. Heritability of spinal pain and consequences of spinal pain: a comprehensive genetic epidemiologic analysis using a population-based sample of 15,328 twins ages 20-71 years

    DEFF Research Database (Denmark)

    Hartvigsen, Jan; Nielsen, Jan; Kyvik, Kirsten Ohm

    2009-01-01

    on 15,328 twin individuals (44% monozygotic and 56% dizygotic) from complete twin pairs were included. Genetic susceptibility explained approximately 38% of lumbar pain, 32% of thoracic pain, and 39% of neck pain. For patterns of pain, estimates were 7% for lumbar/thoracic, 24% for lumbar/cervical, 0......% for thoracic/cervical, and 35% for pain in all 3 areas. Moderate to high genetic correlations indicated a common genetic basis for many spinal pain syndromes. In general, heritability was higher for women, and only a minor age effect was seen. CONCLUSION: Heritability estimates for pain in different spinal......OBJECTIVE: To assess the relative contribution of genetic and environmental factors to different definitions of spinal pain and consequences of spinal pain. METHODS: The Danish Twin Registry contains detailed survey information on spinal pain and its consequences in twins ages 20-71 years...

  8. Postnatal Growth Disadvantage of the Small for Gestational Age Preterm Twins

    Directory of Open Access Journals (Sweden)

    Iris Morag

    2018-04-01

    Full Text Available In this study, we examined early growth characteristics among small-for-gestational-age (SGA preterm twins compared to their appropriate-for-gestational-age (AGA counterparts. A retrospective study evaluated all consecutive twins born between 2008 and 2015 at a tertiary referral center whose gestational age ranged from 30.0 to 34.86 weeks. Included were twins in which one twin was AGA and the other SGA at birth. Changes of ≥2, 1–1.99, and 0–0.99 in z-score between births and 36 weeks post menstrual age (PMA were respectively defined as severe, moderate, and mild postnatal growth failure (PNGF in weight or head circumference (HC. Early neonatal morbidities were documented. Multiple logistic regression analysis was applied to determine conditions associated with PNGF and its severity. Out of 666 sets of twins, 83 met the inclusion criteria. Weight PNGF was similar and mild among the SGA and the AGA groups (0.9 ± 0.46 vs. 0.96 ± 0.44 z-score, respectively, p = 0.24. At 36 weeks PMA, a significantly larger proportion of SGAs were below −2 z-scores in weight (84.3% compared to birth (31.3% or to the AGAs (8.4%. In both groups, weight PNGF correlated with the time needed to regain birth weight. HC PNGF was mild among both groups, yet significantly more prominent among the AGAs (0.39 ± 0.72 z-score vs. SGAs (0.75 ± 0.65 z-score, p = 0.001. We suggest that among preterm SGA infants, the absolute z-score should be used to assess the severity of weight PNGF. Individual nutritional strategies to decrease time to regain birth weight may mitigate severe malnutrition among SGAs.

  9. Hyperthyroidism is associated with work disability and loss of labour market income. A Danish register-based study in singletons and disease-discordant twin pairs.

    Science.gov (United States)

    Brandt, Frans; Thvilum, Marianne; Hegedüs, Laszlo; Brix, Thomas Heiberg

    2015-11-01

    To examine the risk of disability pension and changes in labour market income in patients with hyperthyroidism. From a 5% random sample of the Danish population and twins from the Danish Twin Registry we identified 1942 hyperthyroid singletons and 7768 non-hyperthyroid (matched 1:4) controls as well as 584 same-sex twin pairs discordant for hyperthyroidism. Singletons and twins were followed for a mean of 9 years (range 1-20). Cox regression analysis was used to examine the risk of disability pension and a difference-in-differences model was used to evaluate changes in labour market income. Hyperthyroid individuals had an increased risk of receiving disability pension: hazard ratio (HR) was 1.88, (95% CI: 1.57-2.24). Subdividing as to the cause of hyperthyroidism did not change this finding: Graves' disease (GD) HR was 1.51 (95% CI: 0.87-2.63) and toxic nodular goitre (TNG) HR was 2.10 (95% CI: 1.02-4.36). With respect to labour market income, the income of hyperthyroid individuals increased on average 1189 € less than their controls (Phyperthyroidism. Hyperthyroidism is associated with severe work disability as reflected by an 88% increased risk of receiving disability pension and a significant loss of labour market income. Similar results in monozygotic twins discordant for hyperthyroidism suggest that genetic confounding is unlikely. © 2015 European Society of Endocrinology.

  10. Study of 3-D stress development in parent and twin pairs of a hexagonal close-packed polycrystal: Part II – crystal plasticity finite element modeling

    International Nuclear Information System (INIS)

    Abdolvand, Hamidreza; Majkut, Marta; Oddershede, Jette; Wright, Jonathan P.; Daymond, Mark R.

    2015-01-01

    Stress heterogeneity within each individual grain of polycrystalline Zircaloy-2 is studied using a crystal plasticity finite element (CPFE) model. For this purpose, the weighted Voronoi tessellation method is used to construct 3D geometries of more than 2600 grains based on their center-of-mass positions and volumes as measured by three-dimensional X-ray diffraction (3DXRD) microscopy. The constructed microstructure is meshed with different element densities and for different numbers of grains. Then a selected group of twin and parent pairs are studied. It is shown that the measured average stress for each grain from the 3DXRD experiment is within the stress variation zone of the grain modeled in the CPFE simulation. Also, the CPFE average stress calculation for each grain is in good agreement with the measured average stress values. It is shown that upon considering the stress variations within each grain, stresses in the parent and twin are quite different if they are plotted in the global coordinate system. However, if the stress tensor is rotated into the local coordinate system of the twin habit plane, all the stress components averaged over the presented population are close, except for the shear acting on the twin plane and the transverse stress. This result is significant as it provides information needed to model such parent-twin interactions in crystal plasticity codes

  11. Perceived age as clinically useful biomarker of ageing: cohort study

    DEFF Research Database (Denmark)

    Christensen, Kaare; Thinggaard, Mikael; McGue, Matt

    2009-01-01

    OBJECTIVE: To determine whether perceived age correlates with survival and important age related phenotypes. DESIGN: Follow-up study, with survival of twins determined up to January 2008, by which time 675 (37%) had died. SETTING: Population based twin cohort in Denmark. PARTICIPANTS: 20 nurses, 10...... young men, and 11 older women (assessors); 1826 twins aged >or=70. MAIN OUTCOME MEASURES: Assessors: perceived age of twins from photographs. Twins: physical and cognitive tests and molecular biomarker of ageing (leucocyte telomere length). RESULTS: For all three groups of assessors, perceived age...... increased with increasing discordance in perceived age within the twin pair-that is, the bigger the difference in perceived age within the pair, the more likely that the older looking twin died first. Twin analyses suggested that common genetic factors influence both perceived age and survival. Perceived...

  12. Influence of Host Genetics and Environment on Nasal Carriage of Staphylococcus aureus in Danish Middle-Aged and Elderly Twins

    DEFF Research Database (Denmark)

    Andersen, Paal Skytt; Pedersen, Jacob Krabbe; Fode, Peder

    2012-01-01

    Background. Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. Methods. Nasal swabs were obtained from a national cohort of middle-aged and elde......Background. Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. Methods. Nasal swabs were obtained from a national cohort of middle.......4%-34.5%), and opposite sex (21.4%; 95% CI, 12.0%-33.4%) dizygotic twins. Despite shared childhoods, only 1 of 617 pairs was concordant with respect to lineage. Although heritability increased for S. aureus and lineage persistency, no significant heritability was detected. Conclusion. In this study, host genetic factors...

  13. Genetic Complexity of Episodic Memory: A Twin Approach to Studies of Aging

    Science.gov (United States)

    Kremen, William S.; Spoon, Kelly M.; Jacobson, Kristen C.; Vasilopoulos, Terrie; McCaffery, Jeanne M.; Panizzon, Matthew S.; Franz, Carol E.; Vuoksimaa, Eero; Xian, Hong; Rana, Brinda K.; Toomey, Rosemary; McKenzie, Ruth; Lyons, Michael J.

    2016-01-01

    Episodic memory change is a central issue in cognitive aging, and understanding that process will require elucidation of its genetic underpinnings. A key limiting factor in genetically informed research on memory has been lack of attention to genetic and phenotypic complexity, as if “memory is memory” and all well-validated assessments are essentially equivalent. Here we applied multivariate twin models to data from late-middle-aged participants in the Vietnam Era Twin Study of Aging to examine the genetic architecture of 6 measures from 3 standard neuropsychological tests: the California Verbal Learning Test-2, and Wechsler Memory Scale-III Logical Memory (LM) and Visual Reproductions (VR). An advantage of the twin method is that it can estimate the extent to which latent genetic influences are shared or independent across different measures before knowing which specific genes are involved. The best-fitting model was a higher order common pathways model with a heritable higher order general episodic memory factor and three test-specific subfactors. More importantly, substantial genetic variance was accounted for by genetic influences that were specific to the latent LM and VR subfactors (28% and 30%, respectively) and independent of the general factor. Such unique genetic influences could partially account for replication failures. Moreover, if different genes influence different memory phenotypes, they could well have different age-related trajectories. This approach represents an important step toward providing critical information for all types of genetically informative studies of aging and memory. PMID:24956007

  14. Pregnancy Weight Gain by Gestational Age in Women with Uncomplicated Dichorionic Twin Pregnancies.

    Science.gov (United States)

    Hutcheon, Jennifer A; Platt, Robert W; Abrams, Barbara; Braxter, Betty J; Eckhardt, Cara L; Himes, Katherine P; Bodnar, Lisa M

    2018-03-01

    Twin pregnancies are at increased risk for adverse outcomes and are associated with greater gestational weight gain compared to singleton pregnancies. Studies that disentangle the relationship between gestational duration, weight gain and adverse outcomes are needed to inform weight gain guidelines. We created charts of the mean, standard deviation and select percentiles of maternal weight gain-for-gestational age in twin pregnancies and compared them to singleton curves. We abstracted serial prenatal weight measurements of women delivering uncomplicated twin pregnancies at Magee-Womens Hospital (Pittsburgh, PA, 1998-2013) and merged them with the hospital's perinatal database. Hierarchical linear regression was used to express pregnancy weight gain as a smoothed function of gestational age according to pre-pregnancy BMI category. Charts of week- and day-specific values for the mean, standard deviation, and percentiles of maternal weight gain were created. Prenatal weight measurements (median: 11 [interquartile range: 9, 13] per woman) were available for 1109 women (573 normal weight, 287 overweight, and 249 obese). The slope of weight gain was most pronounced in normal weight women and flattened with increasing pre-pregnancy BMI (e.g. 50th percentiles of 6.8, 5.7, and 3.6 kg at 20 weeks and 19.8, 18.1, and 14.4 at 37 weeks in normal weight, overweight, and obese women, respectively). Weight gain patterns in twins diverged from singletons after 17-19 weeks. Our charts provide a tool for the classification of maternal weight gain in twin pregnancies. Future work is needed to identify the range of weight gain associated with optimal pregnancy health outcomes. © 2018 John Wiley & Sons Ltd.

  15. Secular trends in gestational age and birthweight in twins

    NARCIS (Netherlands)

    Gielen, M.; van Beijsterveldt, C.E.M.; Derom, C.A.; Vlietinck, R; Nijhuis, J.G.; Zeegers, M.P.A.; Boomsma, D.I.

    2010-01-01

    Background: In recent decades, the overall rate of preterm births has increased. The aim of the present study was to examine whether this trend is also seen for multiple gestations. More specifically, we examined if there has been a decrease in gestational age for live born monozygotic (MZ) and

  16. ROTATION PERIODS AND AGES OF SOLAR ANALOGS AND SOLAR TWINS REVEALED BY THE KEPLER MISSION

    International Nuclear Information System (INIS)

    Do Nascimento Jr, J.-D.; Meibom, S.; García, R. A.; Salabert, D.; Ceillier, T.; Mathur, S.; Anthony, F.; Da Costa, J. S.; Castro, M.; Barnes, S. A.

    2014-01-01

    A new sample of solar analogs and twin candidates has been constructed and studied, paying particular attention to their light curves from NASA's Kepler mission. This Letter aims to assess their evolutionary status, derive their rotation and ages, and identify those which are solar analogs or solar twin candidates. We separate out the subgiants that compose a large fraction of the asteroseismic sample, and which show an increase in the average rotation period as the stars ascend the subgiant branch. The rotation periods of the dwarfs, ranging from 6 to 30 days and averaging 19 days, allow us to assess their individual evolutionary states on the main sequence and to derive their ages using gyrochronology. These ages are found to be in agreement with a correlation coefficient of r = 0.79 with independent asteroseismic ages, where available. As a result of this investigation, we are able to identify 34 stars as solar analogs and 22 of them as solar twin candidates

  17. ROTATION PERIODS AND AGES OF SOLAR ANALOGS AND SOLAR TWINS REVEALED BY THE KEPLER MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Do Nascimento Jr, J.-D.; Meibom, S. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); García, R. A.; Salabert, D.; Ceillier, T. [Laboratoire AIM, CEA/DSM,CNRS, Univ. Paris Diderot-IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Mathur, S. [Space Science Institute, 4750 Walnut Street Suite 205, Boulder CO 80301 (United States); Anthony, F.; Da Costa, J. S.; Castro, M. [Universidade Federal do Rio Grande do Norte, UFRN, Dep. de Física Teórica e Experimental, DFTE, CP 1641, 59072-970 Natal, RN (Brazil); Barnes, S. A., E-mail: jdonascimento@cfa.harvard.edu [Leibniz-Institute for Astrophysics, Potsdam D-14467 (Germany)

    2014-08-01

    A new sample of solar analogs and twin candidates has been constructed and studied, paying particular attention to their light curves from NASA's Kepler mission. This Letter aims to assess their evolutionary status, derive their rotation and ages, and identify those which are solar analogs or solar twin candidates. We separate out the subgiants that compose a large fraction of the asteroseismic sample, and which show an increase in the average rotation period as the stars ascend the subgiant branch. The rotation periods of the dwarfs, ranging from 6 to 30 days and averaging 19 days, allow us to assess their individual evolutionary states on the main sequence and to derive their ages using gyrochronology. These ages are found to be in agreement with a correlation coefficient of r = 0.79 with independent asteroseismic ages, where available. As a result of this investigation, we are able to identify 34 stars as solar analogs and 22 of them as solar twin candidates.

  18. Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project

    NARCIS (Netherlands)

    Yokoyama, Y.; Jelenkovic, A.; Sund, R.; Sung, J.; Hopper, J.L.; Ooki, S.; Heikkilä, K.; Aaltonen, S.; Tarnoki, A.D.; Tarnoki, D.L.; Willemsen, G.; Bartels, M.; van Beijsterveldt, C.E.M.; Saudino, K.J.; Cutler, T.L.; Nelson, T.L.; Whitfield, K.E.; Wardle, J.; Llewellyn, C.H.; Fisher, A.; He, M.; Ding, X.; Bjerregaard-Andersen, M.; Beck-Nielsen, H.; Sodemann, M.; Song, Y.M.; Yang, S.; Lee, K.; Jeong, H.U.; Knafo-Noam, A.; Mankuta, D.; Abramson, L.; Burt, S.A.; Klump, K.L.; Ordonana, J.R.; Sanchez-Romera, J.F.; Colodro-Conde, L.; Harris, J.R.; Brandt, I.; Sevenius Nilsen, T.; Craig, J.M.; Saffery, R.; Ji, F.; Ning, F.; Pang, Z.; Dubois, L.; Boivin, M.; Brendgen, M.; Dionne, G.; Vitaro, F.; Martin, N.G.; Medland, S.E.; Montgomery, G.W.; Magnusson, P.K.E.; Pedersen, N.L.; Dahl Aslan, A.K.; Tynelius, P.; Haworth, C.M.A.; Plomin, R.; Rebato, E.; Rose, R.J.; Goldberg, J.H.; Rasmussen, F.; Hur, Y.M.; Sørensen, T.I.A.; Boomsma, D.I.; Kaprio, J.; Silventoinen, K.

    2016-01-01

    We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of

  19. Epigenetic signature of birth weight discordance in adult twins

    DEFF Research Database (Denmark)

    Tan, Qihua; Nielsen, Morten Frost Munk; Heijmans, Bastiaan T

    2014-01-01

    between birth weight and adult life health while controlling for not only genetics but also postnatal rearing environment. We performed an epigenome-wide profiling on blood samples from 150 pairs of adult monozygotic twins discordant for birth weight to look for molecular evidence of epigenetic signatures...... profiling did not reveal epigenetic signatures of birth weight discordance although some sites displayed age-dependent intra-pair differential methylation in the extremely discordant twin pairs....

  20. The heritability of level and rate-of-change in cognitive functioning in Danish twins aged 70 years and older

    DEFF Research Database (Denmark)

    McGue, Matt; Christensen, Kaare

    2002-01-01

    To investigate heritable influences on overall level and rate-of-change in cognitive ability, biometric growth models were fit to cognitive data from nearly 1000 Danish twins age 70 years and older. Twins are participants in the ongoing Longitudinal Study of Aging Danish Twins, a cohort-sequentia......To investigate heritable influences on overall level and rate-of-change in cognitive ability, biometric growth models were fit to cognitive data from nearly 1000 Danish twins age 70 years and older. Twins are participants in the ongoing Longitudinal Study of Aging Danish Twins, a cohort......-sequential study of twins assessed every 2 years for up to four waves. Cognitive ability was assessed by five brief cognitive tasks: a fluency measure, forward and backward digit span, and immediate and delayed list recall. Model-fitting results indicated that although the overall level of cognitive functioning...... was highly heritable (h(2) = .76, 95% confidence interval of .68 to .82), the rate of linear change was not (h(2) = .06, 95% confidence interval of .00 to .57). These findings suggest that the search for specific genes might reasonably focus on average level of cognitive performance, whereas specific...

  1. Heritability and Genome-Wide Association Analyses of Serum Uric Acid in Middle and Old-Aged Chinese Twins

    Directory of Open Access Journals (Sweden)

    Weijing Wang

    2018-03-01

    Full Text Available Serum uric acid (SUA, as the end product of purine metabolism, has proven emerging roles in human disorders. Here based on a sample of 379 middle and old-aged Chinese twin pairs, we aimed to explore the magnitude of genetic impact on SUA variation by performing sex-limitation twin modeling analyses and further detect specific genetic variants related to SUA by conducting a genome-wide association study. Monozygotic (MZ twin correlation for SUA level (rMZ = 0.56 was larger than for dizygotic (DZ twin correlation (rDZ = 0.39. The common effects sex-limitation model provided the best fit with additive genetic parameter (A accounting for 46.3%, common or shared environmental parameter (C accounting for 26.3% and unique/nonshared environmental parameter (E accounting for 27.5% for females and 29.9, 33.1, and 37.0% for males, respectively. Although no SUA-related genetic variants reached genome-wide significance level, 25 SNPs were suggestive of association (P < 1 × 10−5. Most of the SNPs were located in an intronic region and detected to have regulatory effects on gene transcription. The cell-type specific enhancer of skeletal muscle was detected which has been reported to implicate SUA. Two promising genetic regions on chromosome 17 around rs2253277 and chromosome 14 around rs11621523 were found. Gene-based analysis found 167 genes nominally associated with SUA level (P < 0.05, including PTGR2, ENTPD5, well-known SLC2A9, etc. Enrichment analysis identified one pathway of transmembrane transport of small molecules and 20 GO gene sets involving in ion transport, transmembrane transporter activity, hydrolase activity acting on acid anhydrides, etc. In conclusion, SUA shows moderate heritability in women and low heritability in men in the Chinese population and genetic variations are significantly involved in functional genes and regulatory domains that mediate SUA level. Our findings provide clues to further elucidate molecular

  2. Dynamic strain aging of twinning-induced plasticity (TWIP) steel in tensile testing and deep drawing

    International Nuclear Information System (INIS)

    Kim, J.G.; Hong, S.; Anjabin, N.; Park, B.H.; Kim, S.K.; Chin, K.-G.; Lee, S.; Kim, H.S.

    2015-01-01

    The dynamic strain aging (DSA) of metallic materials due to solute atom diffusion to mobile dislocations induce deformation instability with load fluctuations and deformation localizations, hence reducing their sheet formability. In this paper, DSA behaviors of twinning induced plasticity (TWIP) steel with and without Al during tensile testing and deep drawing are investigated in terms of strain localization and the Portevin-Le Chatelier (PLC) band. A theoretical DSA model with internal variables of dislocation density and twin volume fraction is presented for an estimation of strain localization and strain hardening behavior of TWIP steels. The simulation results of the load history and PLC bands during tensile testing and deep drawing are in good agreement with the experimental values. A serration behavior is observed in high-Mn TWIP steels and its tensile residual stress is higher than that in the Al-added TWIP steels, which results in a deformation crack or delayed fracture of deep drawn specimens

  3. Zygosity differences in height and body mass index of twins from infancy to old age: A study of the CODATwins project

    Science.gov (United States)

    Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo; Honda, Chika; Bogl, Leonie H; Aaltonen, Sari; Ji, Fuling; Ning, Feng; Pang, Zengchang; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Burt, S Alexandra; Klump, Kelly L; Medland, Sarah E; Montgomery, Grant W; Kandler, Christian; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Saudino, Kimberly J; Dubois, Lise; Boivin, Michel; Tarnoki, Adam D; Tarnoki, David L; Haworth, Claire MA; Plomin, Robert; Öncel, Sevgi Y; Aliev, Fazil; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Craig, Jeffrey M; Saffery, Richard; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Gatz, Margaret; Butler, David A; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Freitas, Duarte L; Maia, José Antonio; Harden, K Paige; Tucker-Drob, Elliot M; Kim, Bia; Chong, Youngsook; Hong, Changhee; Shin, Hyun Jung; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth JF; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; He, Mingguang; Ding, Xiaohu; Chang, Billy; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Cutler, Tessa L; Hopper, John L; Aujard, Kelly; Magnusson, Patrik KE; Pedersen, Nancy L; Aslan, Anna K Dahl; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Baker, Laura A; Tuvblad, Catherine; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Heikkilä, Kauko; Tan, Qihua; Zhang, Dongfeng; Swan, Gary E; Krasnow, Ruth; Jang, Kerry L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Lichtenstein, Paul; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Tynelius, Per; Duncan, Glen E; Buchwald, Dedra; Corley, Robin P; Huibregtse, Brooke M; Nelson, Tracy L; Whitfield, Keith E; Franz, Carol E; Kremen, William S; Lyons, Michael J; Ooki, Syuichi; Brandt, Ingunn; Nilsen, Thomas Sevenius; Inui, Fujio; Watanabe, Mikio; Bartels, Meike; van Beijsterveldt, Toos CEM; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; Rebato, Esther; Martin, Nicholas G; Iwatani, Yoshinori; Hayakawa, Kazuo; Sung, Joohon; Harris, Jennifer R; Willemsen, Gonneke; Busjahn, Andreas; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Boomsma, Dorret I; Sørensen, Thorkild IA; Kaprio, Jaakko; Silventoinen, Karri

    2015-01-01

    A trend towards greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in means and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the CODATwins project and included 842,951 height and BMI measurements from age 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Likewise, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast the variance of BMI was significantly higher in DZ than in MZ twins particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes. PMID:26337138

  4. Asymmetry and discordance for congenital anomalies in conjoined twins: a report of six cases.

    Science.gov (United States)

    Ornoy, A; Navot, D; Menashi, M; Laufer, N; Chemke, J

    1980-10-01

    Six pairs of conjoined twins have been studied. The first case was a pair of 13-week-old omphalopagus fetuses. One was a holoacradius amorphus and the other had rachischisis and anencephaly. The second case was a pair of omphalopagus twins. One of the twins was macerated and corresponded to a developmental age of 13-14 weeks, while the other was developed to 28-30 weeks of gestation and exhibited urogenital and gastrointestinal defects not found in the smaller twin. In the third case, that of a thoracoomphalopagus, one had cleft lip and palate, pulmonic stenosis, and atresia of the ileocecal valve, while the other did not show these anomalies. In the fourth cae, also omphalopagus twins, one had a lumbosacral meningomyelocele and severe gastrointestinal and urogenital anomalies not found in the second twin. The fifth case was a pair of thoracoomphalopagus twins, sharing a common heart with asymmetrical anomalies. The sixth case was a diprosopus anencephalic conjoined twin. The first pairs of conjoined twins were discordant for several abnormalities in nonshared organs, in addition to having abnormalities of the conjoined organs. It seems that discordance in conjoined twins is not a rare finding. The factors that play a role in discordance of anomalies in conjoined twins are probably similar to the factors in monozygotic twins--i.e., environmental, genetic, and abnormal placental and/or fetal circulation.

  5. Musical Interests and Talent: Twin Jazz Musicians and Twin Studies/Twin Research: Loss of a Preterm Multiple; Conjoined Twin Conception; Depression in Fathers of Twins; Twin-to-Twin Transfusion Syndrome/Twin News: High-Achieving Twins; Twin Children of a Tennis Star; Conjoined Twin Separation; Twin Delivery to a Giant Panda.

    Science.gov (United States)

    Segal, Nancy L

    2017-12-01

    Findings from twin studies of musical interests and talent are reviewed as a backdrop to the lives and careers of twin jazz musicians, Peter and Will Anderson. The Anderson twins exemplify many aspects of twin research, namely their matched musical abilities, shared musical interests, and common career. This overview is followed by reviews of studies and case reports of bereavement in families who have lost a preterm multiple birth infant, the conception of conjoined twins following in vitro fertilization (IVF), depression in fathers of twins, and twin-to-twin transfusion incidence in monochorionic-diamniotic IVF twin pairs. Twins highlighted in the media include high-achieving identical female twins with nearly identical academic standing, tennis star Roger Federer's two sets of identical twin children, surgical separation of craniopagus conjoined twins, and the rare delivery of twins to a 23-year-old giant panda.

  6. Genetic and Environmental Influences on Pulmonary Function and Muscle Strength: The Chinese Twin Study of Aging

    DEFF Research Database (Denmark)

    Tian, Xiaocao; Xu, Chunsheng; Wu, Yili

    2017-01-01

    Genetic and environmental influences on predictors of decline in daily functioning, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), handgrip, and five-times-sit-to-stand test (FTSST), have not been addressed in the aging Chinese population. We performed classical twin...... was moderate for FEV1, handgrip, and FTSST (55-60%) but insignificant for FVC. Only FVC showed moderate control, with shared environmental factors accounting for about 50% of the total variance. In contrast, all measures of pulmonary function and muscle strength showed modest influences from the unique...

  7. Differences in neural and cognitive response to emotional faces in middle-aged dizygotic twins at familial risk of depression

    DEFF Research Database (Denmark)

    Miskowiak, K W; Svendsen, A M B; Harmer, C J

    2017-01-01

    -twin history of depression (high-risk) and 20 were without co-twin history of depression (low-risk). During fMRI, participants viewed fearful and happy faces while performing a gender discrimination task. After the scan, they were given a faces dot-probe task, a facial expression recognition task......BACKGROUND: Negative bias and aberrant neural processing of emotional faces are trait-marks of depression but findings in healthy high-risk groups are conflicting. METHODS: Healthy middle-aged dizygotic twins (N = 42) underwent functional magnetic resonance imaging (fMRI): 22 twins had a co...... the amygdala and ventral prefrontal cortex and pregenual anterior cingulate. This was accompanied by greater fear-specific fronto-temporal response and reduced fronto-occipital response to all emotional faces relative to baseline. The risk groups showed no differences in mood, subjective state or coping...

  8. Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age: A Study of the CODATwins Project.

    Science.gov (United States)

    Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo; Honda, Chika; Bogl, Leonie H; Aaltonen, Sari; Ji, Fuling; Ning, Feng; Pang, Zengchang; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Burt, S Alexandra; Klump, Kelly L; Medland, Sarah E; Montgomery, Grant W; Kandler, Christian; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Saudino, Kimberly J; Dubois, Lise; Boivin, Michel; Tarnoki, Adam D; Tarnoki, David L; Haworth, Claire M A; Plomin, Robert; Öncel, Sevgi Y; Aliev, Fazil; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Craig, Jeffrey M; Saffery, Richard; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Gatz, Margaret; Butler, David A; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Freitas, Duarte L; Maia, José Antonio; Harden, K Paige; Tucker-Drob, Elliot M; Kim, Bia; Chong, Youngsook; Hong, Changhee; Shin, Hyun Jung; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; He, Mingguang; Ding, Xiaohu; Chang, Billy; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Cutler, Tessa L; Hopper, John L; Aujard, Kelly; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Baker, Laura A; Tuvblad, Catherine; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Heikkilä, Kauko; Tan, Qihua; Zhang, Dongfeng; Swan, Gary E; Krasnow, Ruth; Jang, Kerry L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Lichtenstein, Paul; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Tynelius, Per; Duncan, Glen E; Buchwald, Dedra; Corley, Robin P; Huibregtse, Brooke M; Nelson, Tracy L; Whitfield, Keith E; Franz, Carol E; Kremen, William S; Lyons, Michael J; Ooki, Syuichi; Brandt, Ingunn; Nilsen, Thomas Sevenius; Inui, Fujio; Watanabe, Mikio; Bartels, Meike; van Beijsterveldt, Toos C E M; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; Rebato, Esther; Martin, Nicholas G; Iwatani, Yoshinori; Hayakawa, Kazuo; Sung, Joohon; Harris, Jennifer R; Willemsen, Gonneke; Busjahn, Andreas; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Boomsma, Dorret I; Sørensen, Thorkild I A; Kaprio, Jaakko; Silventoinen, Karri

    2015-10-01

    A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.

  9. Genetic and environmental multidimensionality of well- and ill-being in middle aged twin men.

    Science.gov (United States)

    Franz, Carol E; Panizzon, Matthew S; Eaves, Lindon J; Thompson, Wesley; Lyons, Michael J; Jacobson, Kristen C; Tsuang, Ming; Glatt, Stephen J; Kremen, William S

    2012-07-01

    The goals of the study were to determine the extent to which the underlying structure of different types of well-being was multidimensional and whether well- and ill-being were influenced by similar or different genetic and environmental factors. Participants were 1226 male twins ages 51-60, from the Vietnam Era Twin Study of Aging. Measures included: psychological well-being, Multidimensional Personality Questionnaire Well-Being scale (MPQWB), life satisfaction, self-esteem, and depressive symptoms. A two-orthogonal-factor common pathway model fit the data well. Psychological well-being and self-esteem loaded most strongly on Factor 1, which was highly heritable (h(2) = .79). Life satisfaction loaded most strongly on Factor 2, which was only moderately heritable (h(2) = .32). Only MPQWB had measure-specific genetic influences. Depressive symptoms loaded on both factors, and only depressive symptoms had measure-specific common environmental influences. All measures had specific unique environmental influences. Results indicate that well-being is genetically and environmentally multidimensional and that ill-being has partial overlap with both latent factors.

  10. Variance Components Models for Physical Activity With Age as Modifier: A Comparative Twin Study in Seven Countries

    NARCIS (Netherlands)

    Vink, J.M.; Boomsma, D.I.; Medland, S.E.; Moor, H.M. de; Stubbe, J.H.; Corner, B.K.; Martin, N.G.; Skytthea, A.; Kyvik, K.O.; Rose, R..J.; Kujala, U.M.; Kaprio, J.; Harris, J.R.; Pedersen, N.L.; Cherkas, L.; Spector, T.D.; Geus, E.J.

    2011-01-01

    Physical activity is influenced by genetic factors whose expression may change with age. We employed an extension to the classical twin model that allows a modifier variable, age, to interact with the effects of the latent genetic and environmental factors. The model was applied to self-reported

  11. A longitudinal twin study of the association between childhood autistic traits and psychotic experiences in adolescence

    OpenAIRE

    Taylor, Mark J.; Robinson, Elise B.; Happ?, Francesca; Bolton, Patrick; Freeman, Daniel; Ronald, Angelica

    2015-01-01

    Background: This twin study investigated whether autistic traits during childhood were associated with adolescent psychotic experiences. Methods: Data were collected from a community sample of approximately 5000 twin pairs, which included 32 individuals with diagnosed autism spectrum conditions (ASC). Parents rated autistic traits in the twins at four points between ages 8–16 years. Positive, negative, and cognitive psychotic experiences were assessed at age 16 years using self- and parent-re...

  12. Perinatal hepatic infarction in twin-twin transfusion.

    LENUS (Irish Health Repository)

    O'Sullivan, M J

    2012-02-03

    We report a case of a twin pregnancy which was complicated by a twin-twin transfusion in which the recipient twin was noted to have an intra-abdominal echogenic mass. This twin died at two days of age of hepatic infarction. The donor twin was healthy at birth, at thirty weeks\\' gestation, and did not have any subsequent problems. Fetal intra-abdominal echogenicity may be a marker of hepatic infarction.

  13. The Role of Adolescent Nutrition and Physical Activity in the Prediction of Verbal Intelligence during Early Adulthood: A Genetically Informed Analysis of Twin Pairs

    Directory of Open Access Journals (Sweden)

    Dylan B. Jackson

    2015-01-01

    Full Text Available A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined.

  14. The role of adolescent nutrition and physical activity in the prediction of verbal intelligence during early adulthood: a genetically informed analysis of twin pairs.

    Science.gov (United States)

    Jackson, Dylan B; Beaver, Kevin M

    2015-01-05

    A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined.

  15. Study of 3-D stress development in parent and twin pairs of a hexagonal close-packed polycrystal: Part II - Crystal plasticity finite element modeling

    DEFF Research Database (Denmark)

    Abdolvand, Hamidreza; Majkut, Marta; Oddershede, Jette

    2015-01-01

    for each grain from the 3DXRD experiment is within the stress variation zone of the grain modeled in the CPFE simulation. Also, the CPFE average stress calculation for each grain is in good agreement with the measured average stress values. It is shown that upon considering the stress variations within......Stress heterogeneity within each individual grain of polycrystalline Zircaloy-2 is studied using a crystal plasticity finite element (CPFE) model. For this purpose, the weighted Voronoi tessellation method is used to construct 3D geometries of more than 2600 grains based on their center......-of-mass positions and volumes as measured by three-dimensional X-ray diffraction (3DXRD) microscopy. The constructed microstructure is meshed with different element densities and for different numbers of grains. Then a selected group of twin and parent pairs are studied. It is shown that the measured average stress...

  16. Effects of social contact and zygosity on 21-y weight change in male twins.

    Science.gov (United States)

    McCaffery, Jeanne M; Franz, Carol E; Jacobson, Kristen; Leahey, Tricia M; Xian, Hong; Wing, Rena R; Lyons, Michael J; Kremen, William S

    2011-08-01

    Recent evidence indicates that social contact is related to similarities in weight gain over time. However, no studies have examined this effect in a twin design, in which genetic and other environmental effects can also be estimated. We determined whether the frequency of social contact is associated with similarity in weight change from young adulthood (mean age: 20 y) to middle age (mean age: 41 y) in twins and quantified the percentage of variance in weight change attributable to social contact, genetic factors, and other environmental influences. Participants were 1966 monozygotic and 1529 dizygotic male twin pairs from the Vietnam-Era Twin Registry. Regression models tested whether frequency of social contact and zygosity predicted twin pair similarity in body mass index (BMI) change and weight change. Twin modeling was used to partition the percentage variance attributable to social contact, genetic, and other environmental effects. Twins gained an average of 3.99 BMI units, or 13.23 kg (29.11 lb), over 21 y. In regression models, both zygosity (P social contact (P change. In twin modeling, social contact between twins contributed 16% of the variance in BMI change (P change. Frequency of social contact significantly predicted twin pair similarity in BMI and weight change over 21 y, independent of zygosity and other shared environmental influences.

  17. Monozygotic twin pairs discordant for Hashimoto's thyroiditis share a high proportion of thyroid peroxidase autoantibodies to the immunodominant region A. Further evidence for genetic transmission of epitopic "fingerprints"

    DEFF Research Database (Denmark)

    Brix, Thomas Heiberg; Hegedüs, Laszlo; Gardas, Andrzej

    2011-01-01

    Thyroid peroxidase antibodies (TPOAbs) in patients with Hashimoto's thyroiditis (HT) predominantly react with two immunodominant regions (IDR-A, IDR-B). Theoretically, as shown for the level of TPOAbs, the autoantibody epitopic recognition of the IDRs could be under genetic control. To examine this......, we compared the distribution of TPOAb epitopic fingerprints between healthy monozygotic (MZ) co-twins and siblings to patients with clinically overt HT with a control group of euthyroid subjects, matched for sex and age, but without autoimmune thyroid disease (AITD) among their first-degree relatives...

  18. Atopic diseases in twins born after assisted reproduction

    DEFF Research Database (Denmark)

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten Ohm

    2012-01-01

    Jäderberg I, Thomsen SF, Kyvik KO, Skytthe A, Backer V. Atopic diseases in twins born after assisted reproduction. Paediatric and Perinatal Epidemiology 2012; 26: 140-145. We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted...... reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression...... and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0...

  19. Monochorionic twin pregnancies

    NARCIS (Netherlands)

    Hack, K.E.A.

    2008-01-01

    Following widespread application of assisted reproductive technology modalities and the increased age of motherhood, the incidence of twin gestations has increased markedly. Twins are either monozygotic or dizygotic. Dizygotic (i.e. fraternal) twins result from the fertilization of two different

  20. Variance components models for physical activity with age as modifier: a comparative twin study in seven countries

    DEFF Research Database (Denmark)

    Vink, Jacqueline M; Boomsma, Dorret I; Medland, Sarah E

    2011-01-01

    -reported data from twins aged 19 to 50 from seven countries that collaborated in the GenomEUtwin project: Australia, Denmark, Finland, Norway, Netherlands, Sweden and United Kingdom. Results confirmed the importance of genetic influences on physical activity in all countries and showed an age-related decrease......Physical activity is influenced by genetic factors whose expression may change with age. We employed an extension to the classical twin model that allows a modifier variable, age, to interact with the effects of the latent genetic and environmental factors. The model was applied to self...... into account when exploring the genetic and environmental contribution to physical activity. It also suggests that the power of genome-wide association studies to identify the genetic variants contributing to physical activity may be larger in young adult cohorts....

  1. The Danish Twin Registry

    DEFF Research Database (Denmark)

    Skytthe, Axel; Ohm Kyvik, Kirsten; Vilstrup Holm, Niels

    2011-01-01

    Introduction: The Danish Twin Registry is a unique source for studies of genetic, familial and environmental factors on life events, health conditions and diseases. Content: More than 85,000 twin pairs born 1870-2008 in Denmark. Validity and coverage: Four main ascertainment methods have been emp...

  2. Management of small-for-gestational-age twins with absent/reversed end diastolic flow in the umbilical artery: outcome of a policy of daily biophysical profile (BPP).

    Science.gov (United States)

    Kennelly, Máiréad M; Sturgiss, Stephen N

    2007-01-01

    To evaluate a strategy of daily biophysical profile (BPP) for pregnancies with small-for-gestational-age twins and with absent or reversed end diastolic flow (AREDF) in the umbilical artery of one twin and to assess the latency interval between detection and delivery in monochorionic (MC) and dichorionic (DC) twin pregnancy. A search of the Fetal Medicine Database was carried out between 2000 and 2005 at a single tertiary centre to identify all cases with AREDF in the umbilical artery with one small-for-gestational-age twin. Active monitoring with daily BPP was undertaken, once the estimated fetal weights (EFW) was >or= 500 g and at a gestational age of >or= 24 weeks in both twins. Delivery was timed on the basis of an abnormal BPP, two equivocal BPP within 12 h or gestational age of >or= 32(+0) weeks. Twenty-two MC and 17 DC twin pregnancies were identified. There were no fetal losses in the viable actively monitored MC (19) and DC (13) twins. There was a longer latency interval in the MC group at 21.7 days versus 14.4 days in the DC group (p = 0.13). Delivery was indicated for an abnormal BPP (57.8% MC vs 30.8% DC). A strategy of daily BPP can be used to monitor preterm twin fetuses with AREDF, prolonging pregnancy with an acceptable perinatal outcome. Copyright 2007 John Wiley & Sons, Ltd.

  3. Anorexia and bulimia nervosa in same-sex and opposite-sex twins: lack of association with twin type in a nationwide study of Finnish twins.

    Science.gov (United States)

    Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

    2008-12-01

    The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Finnish twins (N=2,426 women, N=1,962 men with known zygosity) from birth cohorts born 1974-1979 were assessed at age 22 to 28 years with a questionnaire for eating disorder symptoms. Based on the questionnaire screen, women (N=292), men (N=53), and their cotwins were interviewed to assess diagnoses of anorexia nervosa and bulimia nervosa (per DSM-IV and broad criteria). In women from opposite-sex twin pairs, the prevalence of DSM-IV or broad anorexia nervosa was not significantly different than that of women from monozygotic pairs or same-sex dizygotic pairs. Of the five male anorexia nervosa probands, only one was from an opposite-sex twin pair. Bulimia nervosa in men was too rare to be assessed by zygosity; the prevalence of DSM-IV or broad bulimia nervosa did not differ in women from opposite- versus same-sex twin pairs. In both sexes, the overall profile of indicators on eating disorders was rather similar between individuals from opposite- and same-sex pairs. The authors found little evidence that the risk for anorexia nervosa, bulimia nervosa, or disordered eating was associated with zygosity or sex composition of twin pairs, thus making it unlikely that in utero femininization or masculinization or socialization effects of growing up with an opposite-sex twin have a major influence on the later development of eating disorders.

  4. Differences in genetic and environmental variation in adult BMI by sex, age, time period, and region: an individual-based pooled analysis of 40 twin cohorts.

    Science.gov (United States)

    Silventoinen, Karri; Jelenkovic, Aline; Sund, Reijo; Yokoyama, Yoshie; Hur, Yoon-Mi; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Honda, Chika; Inui, Fujio; Iwatani, Yoshinori; Watanabe, Mikio; Tomizawa, Rie; Pietiläinen, Kirsi H; Rissanen, Aila; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Tan, Qihua; Zhang, Dongfeng; Pang, Zengchang; Piirtola, Maarit; Aaltonen, Sari; Öncel, Sevgi Y; Aliev, Fazil; Rebato, Esther; Hjelmborg, Jacob B; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Silberg, Judy L; Eaves, Lindon J; Cutler, Tessa L; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Franz, Carol E; Kremen, William S; Lyons, Michael J; Busjahn, Andreas; Nelson, Tracy L; Whitfield, Keith E; Kandler, Christian; Jang, Kerry L; Gatz, Margaret; Butler, David A; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Duncan, Glen E; Buchwald, Dedra; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Jeong, Hoe-Uk; Swan, Gary E; Krasnow, Ruth; Magnusson, Patrik Ke; Pedersen, Nancy L; Dahl Aslan, Anna K; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Tynelius, Per; Baker, Laura A; Tuvblad, Catherine; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Spector, Timothy D; Mangino, Massimo; Lachance, Genevieve; Burt, S Alexandra; Klump, Kelly L; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas S; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Corley, Robin P; Huibregtse, Brooke M; Bartels, Meike; van Beijsterveldt, Catharina Em; Willemsen, Gonneke; Goldberg, Jack H; Rasmussen, Finn; Tarnoki, Adam D; Tarnoki, David L; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth Jf; Hopper, John L; Sung, Joohon; Maes, Hermine H; Turkheimer, Eric; Boomsma, Dorret I; Sørensen, Thorkild Ia; Kaprio, Jaakko

    2017-08-01

    Background: Genes and the environment contribute to variation in adult body mass index [BMI (in kg/m 2 )], but factors modifying these variance components are poorly understood. Objective: We analyzed genetic and environmental variation in BMI between men and women from young adulthood to old age from the 1940s to the 2000s and between cultural-geographic regions representing high (North America and Australia), moderate (Europe), and low (East Asia) prevalence of obesity. Design: We used genetic structural equation modeling to analyze BMI in twins ≥20 y of age from 40 cohorts representing 20 countries (140,379 complete twin pairs). Results: The heritability of BMI decreased from 0.77 (95% CI: 0.77, 0.78) and 0.75 (95% CI: 0.74, 0.75) in men and women 20-29 y of age to 0.57 (95% CI: 0.54, 0.60) and 0.59 (95% CI: 0.53, 0.65) in men 70-79 y of age and women 80 y of age, respectively. The relative influence of unique environmental factors correspondingly increased. Differences in the sets of genes affecting BMI in men and women increased from 20-29 to 60-69 y of age. Mean BMI and variances in BMI increased from the 1940s to the 2000s and were greatest in North America and Australia, followed by Europe and East Asia. However, heritability estimates were largely similar over measurement years and between regions. There was no evidence of environmental factors shared by co-twins affecting BMI. Conclusions: The heritability of BMI decreased and differences in the sets of genes affecting BMI in men and women increased from young adulthood to old age. The heritability of BMI was largely similar between cultural-geographic regions and measurement years, despite large differences in mean BMI and variances in BMI. Our results show a strong influence of genetic factors on BMI, especially in early adulthood, regardless of the obesity level in the population. © 2017 American Society for Nutrition.

  5. Does the sex of one's co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts.

    Science.gov (United States)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero; Ahrenfeldt, Linda; Pietiläinen, Kirsi H; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Hur, Yoon-Mi; Jeong, Hoe-Uk; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Cutler, Tessa L; Kandler, Christian; Jang, Kerry L; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Derom, Catherine A; Vlietinck, Robert F; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos C E M; Pang, Zengchang; Tan, Qihua; Zhang, Dongfeng; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Hjelmborg, Jacob V B; Rebato, Esther; Swan, Gary E; Krasnow, Ruth; Busjahn, Andreas; Lichtenstein, Paul; Öncel, Sevgi Y; Aliev, Fazil; Baker, Laura A; Tuvblad, Catherine; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Yokoyama, Yoshie; Hopper, John L; Loos, Ruth J F; Boomsma, Dorret I; Sørensen, Thorkild I A; Silventoinen, Karri; Kaprio, Jaakko

    2017-01-01

    The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and the prevalence of being overweight or obese between men and women from OS and SS dizygotic twin pairs. The data were derived from the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) database, and included 68,494 SS and 53,808 OS dizygotic twin individuals above the age of 20 years from 31 twin cohorts representing 19 countries. Zygosity was determined by questionnaires or DNA genotyping depending on the study. Multiple regression and logistic regression models adjusted for cohort, age, and birth year with the twin type as a predictor were carried out to compare height and BMI in twins from OS pairs with those from SS pairs and to calculate the adjusted odds ratios and 95% confidence intervals for being overweight or obese. OS females were, on average, 0.31 cm (95% confidence interval (CI) 0.20, 0.41) taller than SS females. OS males were also, on average, taller than SS males, but this difference was only 0.14 cm (95% CI 0.02, 0.27). Mean BMI and the prevalence of overweight or obesity did not differ between males and females from SS and OS twin pairs. The statistically significant differences between OS and SS twins for height were small and appeared to reflect our large sample size rather than meaningful differences of public health relevance. We found no evidence to support the hypothesis that prenatal hormonal exposure or postnatal socialization (i.e., having grown up with a twin of the opposite sex) has a major impact on height and BMI in adulthood.

  6. Effect of existing twin boundaries in martensite on the rubber-like behavior and ageing effect in Au-Cd alloys

    International Nuclear Information System (INIS)

    Murakami, Y.; Nakajima, Y.; Otsuka, K.; Ohba, T.

    1995-01-01

    The effect of existing twin(or intervariant) boundaries on both the rubber-like behavior and the ageing effect(Af temperature increase) was studied by using γ 2 ' (orthorhombic) and ζ 2 '(trigonal) martensites in Au-Cd alloys. A typical rubber-like behavior was observed even in a single-variant specimen of γ 2 ' martensite, which proves that the presence of twin boundaries is not the necessary condition for the rubber-like behavior. Thus, the previously proposed mechanism for pinning of boundaries was denied. However, the observed Af temperature increase in the ζ 2 ' martensite was more pronounced in the specimen with twin boundaries(multi-variant state) rather than that without twin boundaries(single-variant state). Thus, it was found that the presence of twin boundaries affects the development of ageing effect though it is not the direct origin for the phenomenon. (orig.)

  7. Does marriage inhibit antisocial behavior?: An examination of selection vs causation via a longitudinal twin design.

    Science.gov (United States)

    Burt, S Alexandra; Donnellan, M Brent; Humbad, Mikhila N; Hicks, Brian M; McGue, Matt; Iacono, William G

    2010-12-01

    Previous studies have indicated that marriage is negatively associated with male antisocial behavior. Although often interpreted as a causal association, marriage is not a random event. As such, the association may stem from selection processes, whereby men less inclined toward antisocial behavior are more likely to marry. To evaluate selection vs causation explanations of the association between marriage and desistence from antisocial behavior. Co-twin control analyses in a prospective twin study provided an analogue of the idealized counterfactual model of causation. The co-twin control design uses the unmarried co-twin of a married twin to estimate what the married twin would have looked like had he remained unmarried. Discordant monozygotic (MZ) twins are particularly informative because they share a common genotype and rearing environment. General community study. Two hundred eighty-nine male-male twin pairs (65.1% MZ) from the Minnesota Twin Family Study underwent assessment at 17, 20, 24, and 29 years of age. None of the participants were married at 17 years of age, and 2.6% were married at 20 years of age. By 29 years of age, 58.8% of the participants were or had been married. A tally of criterion C symptoms of DSM-III-R antisocial personality disorder, as assessed via structured clinical interview. Mean differences in antisocial behavior across marital status at age 29 years were present even at 17 and 20 years of age, suggesting a selection process. However, the within-pair effect of marriage was significant for MZ twins, such that the married twin engaged in less antisocial behavior following marriage than his unmarried co-twin. Results were equivalent to those in dizygotic twins and persisted when controlling for prior antisocial behavior. Results indicate an initial selection effect, whereby men with lower levels of antisocial behavior are more likely to marry. However, this tendency to refrain from antisocial behavior appears to be accentuated by the

  8. The USC Adult Twin Cohorts: International Twin Study and California Twin Program.

    Science.gov (United States)

    Cozen, Wendy; Hwang, Amie E; Cockburn, Myles G; Hamilton, Ann S; Zadnick, John; Mack, Thomas M

    2013-02-01

    The study of twin subjects permits the documentation of crude heritability and may promote the identification of specific causal alleles. We believe that at the current time, the chief research advantage of twins as subjects, especially monozygotic twins, is that the commonality of their genetic and cultural identity simplifies the interpretation of biological associations. In order to study genetic and environmental determinants of cancer and chronic diseases, we developed two twin registries, maintained at the University of Southern California: The International Twin Study (ITS) and the California Twin Program (CTP). The ITS is a volunteer registry of twins with cancer and chronic disease consisting of 17,245 twin pairs affected by cancer and chronic disease, respectively, ascertained by advertising in periodicals from 1980-1991. The CTP is a population-based registry of California-born twin pairs ascertained by linking the California birth records to the State Department of Motor Vehicles. Over 51,000 individual California twins representing 36,965 pairs completed and returned 16-page questionnaires. Cancer diagnoses in the California twins are updated by regular linkage to the California Cancer Registry. Over 5,000 cancer patients are represented in the CTP. Twins from both registries have participated extensively in studies of breast cancer, melanoma, lymphoma, multiple sclerosis, systemic lupus erythematosus, diabetes mellitus type 1, mammographic density, smoking, and other traits and conditions.

  9. The Solar Twin Planet Search. III. The [Y/Mg] clock: estimating stellar ages of solar-type stars

    Science.gov (United States)

    Tucci Maia, M.; Ramírez, I.; Meléndez, J.; Bedell, M.; Bean, J. L.; Asplund, M.

    2016-05-01

    Context. Solar twins are stars with similar stellar (surface) parameters to the Sun that can have a wide range of ages. This provides an opportunity to analyze the variation of their chemical abundances with age. Nissen (2015, A&A, 579, A52) recently suggested that the abundances of the s-process element Y and the α-element Mg could be used to estimate stellar ages. Aims: This paper aims to determine with high precision the Y, Mg, and Fe abundances for a sample of 88 solar twins that span a broad age range (0.3-10.0 Gyr) and investigate their use for estimating ages. Methods: We obtained high-quality Magellan Inamori Kyocera Echelle (MIKE) spectra and determined Y and Mg abundances using equivalent widths and a line-by-line differential method within a 1D LTE framework. Stellar parameters and iron abundances were measured in Paper I of this series for all stars, but a few (three) required a small revision. Results: The [Y/Mg] ratio shows a strong correlation with age. It has a slope of -0.041 ± 0.001 dex/Gyr and a significance of 41σ. This is in excellent agreement with the relation first proposed by Nissen (2015). We found some outliers that turned out to be binaries where mass transfer may have enhanced the yttrium abundance. Given a precise measurement of [Y/Mg] with typical error of 0.02 dex in solar twins, our formula can be used to determine a stellar age with ~0.8 Gyr precision in the 0 to 10 Gyr range. Based on observations obtained at the Clay Magellan Telescopes at Las Campanas Observatory, Chile and at the 3.6 m Telescope at the La Silla ESO Observatory, Chile (program ID 188.C-0265).

  10. Ageing without detailed balance in the bosonic contact and pair-contact processes: exact results

    International Nuclear Information System (INIS)

    Baumann, Florian; Henkel, Malte; Pleimling, Michel; Richert, Jean

    2005-01-01

    Ageing in systems without detailed balance is studied in the exactly solvable bosonic contact process and the critical bosonic pair-contact process. The two-time correlation function and the two-time response function are explicitly found. In the ageing regime, the dynamical scaling of these is analysed and exact results for the ageing exponents and the scaling functions are derived. For the critical bosonic pair-contact process, the autocorrelation and autoresponse exponents agree but the ageing exponents a and b are shown to be distinct

  11. The etiologic role of genetic and environmental factors in criminal behavior as determined from full- and half-sibling pairs: an evaluation of the validity of the twin method.

    Science.gov (United States)

    Kendler, K S; Lönn, S L; Maes, H H; Sundquist, J; Sundquist, K

    2015-07-01

    Twin studies have shown that criminal behavior (CB) is influenced by both genetic and shared environmental factors. Could these results be replicated using full-siblings and half-siblings? In 911 009 full-siblings reared together (FSRT), 41 872 half-siblings reared together (HSRT) and 52 590 half-siblings reared apart (HSRA), CB was assessed from the Swedish Crime Register. Modeling, including testing for age differences and rearing status, was performed using the OpenMx package. Five sibling models were fitted examining FSRT and HSRT 0-2 years different in age, and both FSRT and HSRT, and FSRT, HSRT and HSRA 0-10 years different in age with and without a specified shared environment indexing age differences. Heritability estimates for CB ranged from 33 to 55% in females and 39 to 56% in males, similar to those found in our prior twin study on the same population. Estimates for the shared environment varied from 1 to 14% in females and 10 to 23% in males, lower than those estimated in the twin study. The specified shared environment indexed by sibling age differences was significant in all models tested. Heritability estimates for CB from full- and half-siblings closely approximated those found from twins in the same population, validating the twin method. Shared environmental estimates were lower, suggesting the presence of shared environmental factors for CB specific to twins. When rearing status can be assessed, full- and half-siblings offer an additional method for assessing the role of genetic and environmental factors in complex disorders. However, age differences in siblings may need to be included in the models.

  12. Monozygotic twins discordant for ROHHAD phenotype.

    Science.gov (United States)

    Patwari, Pallavi P; Rand, Casey M; Berry-Kravis, Elizabeth M; Ize-Ludlow, Diego; Weese-Mayer, Debra E

    2011-09-01

    Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) falls within a group of pediatric disorders with both respiratory control and autonomic nervous system dysregulation. Children with ROHHAD typically present after 1.5 years of age with rapid weight gain as the initial sign. Subsequently, they develop alveolar hypoventilation, autonomic nervous system dysregulation, and, if untreated, cardiorespiratory arrest. To our knowledge, this is the first report of discordant presentation of ROHHAD in monozygotic twins. Twin girls, born at term, had concordant growth and development until 8 years of age. From 8 to 12 years of age, the affected twin developed features characteristic of ROHHAD including obesity, alveolar hypoventilation, scoliosis, hypothalamic dysfunction (central diabetes insipidus, hypothyroidism, premature pubarche, and growth hormone deficiency), right paraspinal/thoracic ganglioneuroblastoma, seizures, and autonomic dysregulation including altered pain perception, large and sluggishly reactive pupils, hypothermia, and profound bradycardia that required a cardiac pacemaker. Results of genetic testing for PHOX2B (congenital central hypoventilation syndrome disease-defining gene) mutations were negative. With early recognition and conservative management, the affected twin had excellent neurocognitive outcome that matched that of the unaffected twin. The unaffected twin demonstrated rapid weight gain later in age but not development of signs/symptoms consistent with ROHHAD. This discordant twin pair demonstrates key features of ROHHAD including the importance of early recognition (especially hypoventilation), complexity of signs/symptoms and clinical course, and importance of initiating comprehensive, multispecialty care. These cases confound the hypothesis of a monogenic etiology for ROHHAD and indicate alternative etiologies including autoimmune or epigenetic phenomenon or a combination of genetic

  13. A Computational Discriminability Analysis on Twin Fingerprints

    Science.gov (United States)

    Liu, Yu; Srihari, Sargur N.

    Sharing similar genetic traits makes the investigation of twins an important study in forensics and biometrics. Fingerprints are one of the most commonly found types of forensic evidence. The similarity between twins’ prints is critical establish to the reliability of fingerprint identification. We present a quantitative analysis of the discriminability of twin fingerprints on a new data set (227 pairs of identical twins and fraternal twins) recently collected from a twin population using both level 1 and level 2 features. Although the patterns of minutiae among twins are more similar than in the general population, the similarity of fingerprints of twins is significantly different from that between genuine prints of the same finger. Twins fingerprints are discriminable with a 1.5%~1.7% higher EER than non-twins. And identical twins can be distinguished by examine fingerprint with a slightly higher error rate than fraternal twins.

  14. The Child and Adolescent Twin Study in Sweden (CATSS).

    Science.gov (United States)

    Anckarsäter, Henrik; Lundström, Sebastian; Kollberg, Linnea; Kerekes, Nora; Palm, Camilla; Carlström, Eva; Långström, Niklas; Magnusson, Patrik K E; Halldner, Linda; Bölte, Sven; Gillberg, Christopher; Gumpert, Clara; Råstam, Maria; Lichtenstein, Paul

    2011-12-01

    The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding the children's somatic and mental health and social environment in connection with their 9th or 12th birthdays (CATSS-9/12). By January 2010, 8,610 parental interviews concerning 17,220 twins had been completed, with an overall response rate of 80%. At age 15 (CATSS-15) and 18 (CATSS-18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. Twin pairs in CATSS-9/12 with one or both twins screening positive for autism spectrum disorders, attention deficit/hyperactivity disorder, tic disorders, developmental coordination disorder, learning disorders, oppositional defiant disorder, conduct disorder, obsessive-compulsive disorder, and/or eating problems have been followed with in-depth questionnaires on family, social environment and personality, and subsequently by clinical assessments at age 15 together with randomly selected population controls, including 195 clinically assessed twin pairs from the first 2 year cohorts (CATSS-15/DOGSS). This article describes the cohorts and study groups, data collection, and measures used. Prevalences, distributions, heritability estimates, ages at onset, and sex differences of mental health problems in the CATSS-9/12, that were analyzed and found to be overall comparable to those of other clinical and epidemiological studies. The CATSS study has the potential of answering important questions on the etiology of childhood mental health problems and their role in the development of later adjustment problems.

  15. Genetic and Environmental Contributions to Behavioral Stability and Change in Children 6-36 months of Age Using Louisville Twin Study Data.

    Science.gov (United States)

    Davis, Deborah Winders; Finkel, Deborah; Turkheimer, Eric; Dickens, William

    2015-11-01

    The Infant Behavior Record (IBR) from the Bayley Scales of Infant Development has been used to study behavioral development since the 1960s. Matheny (1983) examined behavioral development at 6, 12, 18, and 24 months from the Louisville Twin Study (LTS). The extracted temperament scales included Task Orientation, Affect-Extraversion, and Activity. He concluded that monozygotic twins were more similar than same-sex dizygotic twins on these dimensions. Since this seminal work was published, a larger LTS sample and more advanced analytical methods are available. In the current analyses, Choleksy decomposition was applied to behavioral data (n = 1231) from twins 6-36 months. Different patterns of genetic continuity vs genetic innovations were identified for each IBR scale. Single common genetic and shared environmental factors explained cross-age twin similarity in the Activity scale. Multiple shared environmental factors and a single genetic factor coming on line at age 18 months contributed to Affect-Extraversion. A single shared environmental factor and multiple genetic factors explained cross-age twin similarity in Task Orientation.

  16. A Danish population-based twin study on autism spectrum disorders

    DEFF Research Database (Denmark)

    Nordenbaek, Claudia; Jorgensen, Meta; Kyvik, Kirsten Ohm

    2014-01-01

    Genetic epidemiological studies of Autism Spectrum Disorders (ASDs) based on twin pairs ascertained from the population and thoroughly assessed to obtain a high degree of diagnostic validity are few. All twin pairs aged 3-14 years in the nationwide Danish Twin Registry were approached. A three......-step procedure was used. Five items from the "Child Behaviour Checklist" (CBCL) were used in the first screening phase, while screening in the second phase included the "Social and Communication Questionnaire" and the "Autism Spectrum Screening Questionnaire". The final clinical assessment was based on "gold...

  17. Genetic influence on the associations between IGF-I and glucose metabolism in a cohort of elderly twins

    DEFF Research Database (Denmark)

    Jensen, Rikke Beck; Thankamony, Ajay; Holst, Klaus K.

    2018-01-01

    OBJECTIVE: IGF-I may be a marker of later metabolic and cardiovascular disease. The interactions between IGF-I and glucose metabolism are multifactorial, and there is potential confounding from several secondary effects. In this study, we examined the interaction between IGF-I and glucose...... metabolism in a large cohort of clinically well-characterized elderly twins. DESIGN: A total of 303 twin pairs of the same gender (606 twins) were included in the study; 125 monozygotic and 178 dizygotic twin pairs. METHODS: A clinical examination including a standard oral glucose tolerance test (OGTT.......11). In a multiple regression analysis (adjusting for age, gender and twin status), there was a negative association between IGF-I and insulin sensitivity (B: -0.13, SE 0.03, P cohort of 606 twins. The associations between IGF...

  18. Monozygotic twins with CAPN5 autosomal dominant neovascular inflammatory vitreoretinopathy.

    Science.gov (United States)

    Rowell, Hannah A; Bassuk, Alexander G; Mahajan, Vinit B

    2012-01-01

    The purpose of this study was to describe the clinical findings in a set of monozygotic twins with autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) over a 23-year period. A pair of female twins were examined between 26 and 49 years of age. The concordance and discordance of their clinical features were determined. The CAPN5 gene was sequenced using genomic DNA. Both twins of an affected father demonstrated Stage I ADNIV with mild vitreous cells and a negative b-wave on electroretinography. Genetic analysis confirmed a guanine to thymine nucleotide (c.728G>T, pArg243Leu) mutation in the CAPN5 gene. Over the course of 23 years, each twin progressed to stage III disease, showing posterior uveitis, cystoid macular edema, intraocular fibrosis, early retinal neovascularization, retinal degeneration, and cataract. Disease progression varied moderately between each twin and was asymmetrical between eyes. Twin A had 20/70 and 20/125 in the right and left eye, respectively, and underwent vitrectomy surgery and intravitreal injections with bevacizumab for recurrent cystoid macular edema. Twin B maintained 20/20 and 20/40 in the right and left eye, respectively without intervention. There was asymmetry between the eyes and some discordance in the rate of disease progression in these monozygotic twins with ADNIV. The overall high disease concordance suggests genetic factors play a major role in clinical manifestations in CAPN5 vitreoretinopathy.

  19. [Genetic and environmental contributions to body mass index in a Spanish adolescent twin sample].

    Science.gov (United States)

    Iranzo-Tatay, Carmen; Gimeno-Clemente, Natalia; Livianos-Aldana, Lorenzo; Rojo-Moreno, Luis

    2015-08-21

    Twin and family studies support large genetic influences on variability in body mass index (BMI), with heritability estimates ranging from 47% to over 90%. Our objective was to study the relative contributions of genetics and environment to BMI, evaluating sex differences, in an adolescent twin sample from Valencia, Spain. Five hundred eighty-four pairs of adolescent twins between 13 and 18 years of age completed the study (82 monozygotic [MZ] and 87 dizygotic [DZ] pairs of male twins, 118 MZ and 102 DZ pairs of female twins, and 195 opposite-sex pairs of DZ twins). To determine zygosity, teachers responded a questionnaire on physical similarity. They also measured the participant's height and weight. BMI was calculated and weight status was determined according to age. We used twin models to assess genetic and environmental (common and unique) factors affecting BMI. There was a 7.1% frequency of overweight and 2.8% of obesity. The estimated heritability of BMI was 88.0% in boys and 72.1% in girls, with the remaining variance attributable to non-shared environment in boys (12.0%) and 8.8% in girls. It was only in girls that common environment had an effect on BMI. Genetics appears to play an important role in explaining the variability in BMI in the adolescence, with slight variations between boys and girls. Common environmental factors exert their influence on BMI only in girls. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  20. Genetic contribution to the relationship between social role function and depressive symptoms in Japanese elderly twins: a twin study.

    Science.gov (United States)

    Nishihara, Reiko; Inui, Fujio; Kato, Kenji; Tomizawa, Rie; Hayakawa, Kazuo

    2011-03-01

    Social role function is the capacity to maintain interpersonal relationships and is essential for being independent in the community. Limitations in social role function often coexist with depressive symptoms, suggesting a possible common mechanistic basis. We investigated whether the observed association between these traits is mainly a result of genetic or environmental influences. In 2008, a questionnaire was sent to 745 male twins aged 65 years and older. Our sample included 397 male twins. The number of monozygotic twins was 302, and dizygotic was 95. Among the twin pairs for whom data were available for both twins, 75 twin pairs (150 individuals) were monozygotic and 28 pairs (56 individuals) were dizygotic. Social role function was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Depressive symptoms were measured by the 15-item version of the Geriatric Depression Scale. Relative importance of genes and environments for the phenotypes was calculated using structural equation analyses. Our results show that genetic influence was the major contributor to the relationship between social role function and depressive symptoms, and non-shared environmental influence was important for overall variation in each trait. We concluded that focusing on a non-shared environment is an essential approach for maintaining social role function and psychological well-being. It is suggested that treatments specific to depressive symptoms are more effective than indirect intervention targeting social role function. © 2011 The Authors. Psychogeriatrics © 2011 Japanese Psychogeriatric Society.

  1. Neuroanatomic alterations and social and communication deficits in monozygotic twins discordant for autism disorder.

    Science.gov (United States)

    Mitchell, Shanti R; Reiss, Allan L; Tatusko, Danielle H; Ikuta, Ichiro; Kazmerski, Dana B; Botti, Jo-Anna C; Burnette, Courtney P; Kates, Wendy R

    2009-08-01

    Investigating neuroanatomic differences in monozygotic twins who are discordant for autism can help unravel the relative contributions of genetics and environment to this pervasive developmental disorder. The authors used magnetic resonance imaging (MRI) to investigate several brain regions of interest in monozygotic twins who varied in degree of phenotypic discordance for narrowly defined autism. The subjects were 14 pairs of monozygotic twins between the ages of 5 and 14 years old and 14 singleton age- and gender-matched typically developing comparison subjects. The monozygotic twin group was a cohort of children with narrowly defined autistic deficits and their co-twins who presented with varying levels of autistic deficits. High-resolution MRIs were acquired and volumetric/area measurements obtained for the frontal lobe, amygdala, and hippocampus and subregions of the prefrontal cortex, corpus callosum, and cerebellar vermis. No neurovolumetric/area differences were found between twin pairs. Relative to typically developing comparison subjects, dorsolateral prefrontal cortex volumes and anterior areas of the corpus callosum were significantly altered in autistic twins, and volumes of the posterior vermis were altered in both autistic twins and co-twins. Intraclass correlation analysis of brain volumes between children with autism and their co-twins indicated that the degree of within-pair neuroanatomic concordance varied with brain region. In the group of subjects with narrowly defined autism only, dorsolateral prefrontal cortex, amygdala, and posterior vermis volumes were significantly associated with the severity of autism based on scores from the Autism Diagnostic Observation Schedule-Generic. These findings support previous research demonstrating alterations in the prefrontal cortex, corpus callosum, and posterior vermis in children with autism and further suggest that alterations are associated with the severity of the autism phenotype. Continued research

  2. Oliver Sacks: Our Correspondence About Twins/Twin Research: Vanishing Twins Syndrome; Discordant Sex in MZ Twins; Pregnancy Outcomes in IVF and ICSI Conceived Twins/Print and Media: Superfetated Twins; Twins Discordant for Smoking; Twins in Fashion; Yale University Twin Hockey Players; Conjoined Twin-Visiting Professor.

    Science.gov (United States)

    Segal, Nancy L

    2017-08-01

    The late neurologist and author, Oliver Sacks, published an insightful 1986 review of Marjorie Wallace's book, The Silent Twins, in the New York Times. Taking exception to his assertion about Sir Francis Galton, I wrote a letter to the Times' editor. The letter was unpublished, but it brought a wonderful response from Sacks himself that is reproduced and examined. Next, brief reviews of twin research concerning the vanishing twin syndrome (VTS), discordant sex in a monozygotic (MZ) twin pair, and multiple pregnancy outcomes from assisted reproductive technology (ART) are presented. This section is followed by popular coverage of superfetated twins, smoking-discordant co-twins, twins in fashion, Yale University twin hockey players, and a visiting professor who was a conjoined twin.

  3. Electron-pair production in Pb - Au collisions at 40 AGeV

    CERN Document Server

    Damjanovic, Sanja

    2002-01-01

    This thesis contains the first experimental results on electron-pair production from the CERES/NA45 experiment at the CERN SPS after the upgrade with a Time Projection Chamber (TPC). The data were taken in late 1999 with a Pb-beam on a Au-target at a beam energy of 40 AGeV. Out of about 8 Million events with a 30$$ centrality selection, 249$pm$28 $e^{+}e^{-}$ pairs for masses $le$0.2 GeV/c$^{2}$ with a S/B ratio of 1/1, and 185$pm$48 $e^{+}e^{-}$ pairs for masses $>$0.2 GeV/c$^{2}$ with a S/B ratio of 1/6 were reconstructed. The low-mass sample agrees with the expectation from hadronic decays. The high-mass sample shows an excess of a factor of 5.1$pm$1.3(stat)$pm$1.0(syst) above that expectation, considerably more than the values around 2.5-3.5 observed before at the higher beam energy of 160 AGeV. The excess yield is dominantly associated with pair transverse momenta $<$0.5 GeV/c, consistent with the findings at 160 AGeV. The theoretical relevance of the results is discussed in some detail. The dilepton ...

  4. Intrapair Similarity of Computer Self-Efficacy in Turkish Adolescent Twins

    Science.gov (United States)

    Deryakulu, Deniz; Mcilroy, David; Ursavas, Ömer Faruk; Çaliskan, Erkan

    2016-01-01

    The purpose of this study is to investigate genetic and environmental influences on computer self-efficacy. A total of 165 Turkish twin-pairs participated in the study. Participants' mean age was 12.45 (SD = 1.82). The results of paired t-test comparisons showed no significant differences in monozygotic, and both same-sex and opposite-sex…

  5. Decomposing variation in male reproductive success: age-specific variances and covariances through extra-pair and within-pair reproduction.

    Science.gov (United States)

    Lebigre, Christophe; Arcese, Peter; Reid, Jane M

    2013-07-01

    Age-specific variances and covariances in reproductive success shape the total variance in lifetime reproductive success (LRS), age-specific opportunities for selection, and population demographic variance and effective size. Age-specific (co)variances in reproductive success achieved through different reproductive routes must therefore be quantified to predict population, phenotypic and evolutionary dynamics in age-structured populations. While numerous studies have quantified age-specific variation in mean reproductive success, age-specific variances and covariances in reproductive success, and the contributions of different reproductive routes to these (co)variances, have not been comprehensively quantified in natural populations. We applied 'additive' and 'independent' methods of variance decomposition to complete data describing apparent (social) and realised (genetic) age-specific reproductive success across 11 cohorts of socially monogamous but genetically polygynandrous song sparrows (Melospiza melodia). We thereby quantified age-specific (co)variances in male within-pair and extra-pair reproductive success (WPRS and EPRS) and the contributions of these (co)variances to the total variances in age-specific reproductive success and LRS. 'Additive' decomposition showed that within-age and among-age (co)variances in WPRS across males aged 2-4 years contributed most to the total variance in LRS. Age-specific (co)variances in EPRS contributed relatively little. However, extra-pair reproduction altered age-specific variances in reproductive success relative to the social mating system, and hence altered the relative contributions of age-specific reproductive success to the total variance in LRS. 'Independent' decomposition showed that the (co)variances in age-specific WPRS, EPRS and total reproductive success, and the resulting opportunities for selection, varied substantially across males that survived to each age. Furthermore, extra-pair reproduction increased

  6. Maternal age at first birth and offspring criminality: using the children of twins design to test causal hypotheses.

    Science.gov (United States)

    Coyne, Claire A; Långström, Niklas; Rickert, Martin E; Lichtenstein, Paul; D'Onofrio, Brian M

    2013-02-01

    Teenage childbirth is a risk factor for poor offspring outcomes, particularly offspring antisocial behavior. It is not clear, however, if maternal age at first birth (MAFB) is causally associated with offspring antisocial behavior or if this association is due to selection factors that influence both the likelihood that a young woman gives birth early and that her offspring engage in antisocial behavior. The current study addresses the limitations of previous research by using longitudinal data from Swedish national registries and children of siblings and children of twins comparisons to identify the extent to which the association between MAFB and offspring criminal convictions is consistent with a causal influence and confounded by genetic or environmental factors that make cousins similar. We found offspring born to mothers who began childbearing earlier were more likely to be convicted of a crime than offspring born to mothers who delayed childbearing. The results from comparisons of differentially exposed cousins, especially born to discordant monozygotic twin sisters, provide support for a causal association between MAFB and offspring criminal convictions. The analyses also found little evidence for genetic confounding due to passive gene-environment correlation. Future studies are needed to replicate these findings and to identify environmental risk factors that mediate this causal association.

  7. Maternal age at first birth and offspring criminality: Using the children-of-twins design to test causal hypotheses

    Science.gov (United States)

    Coyne, Claire A; Långström, Niklas; Rickert, Martin E; Lichtenstein, Paul; D’Onofrio, Brian M

    2013-01-01

    Teenage childbirth is a risk factor for poor offspring outcomes, particularly offspring antisocial behaviour. It is not clear if maternal age at first birth (MAFB) is causally associated with offspring antisocial behavior or if this association is due to selection factors that influence both the likelihood that a young woman gives birth early and that her offspring engage in antisocial behavior. The current study addresses the limitations of previous research by using longitudinal data from Swedish national registries and children-of-siblings and children-of-twins comparisons to identify the extent to which the association between MAFB and offspring criminal convictions is consistent with a causal influence and confounded by genetic or environmental factors that make cousins similar. We found offspring born to mothers who began childbearing earlier were more likely to be convicted of a crime than offspring born to mothers who delayed childbearing. The results from comparisons of differentially exposed cousins, especially born to discordant MZ twin sisters, provide support for a causal association between MAFB and offspring criminal convictions. The analyses also found little evidence for genetic confounding due to passive gene-environment correlation. Future studies are needed to replicate these findings and to identify environmental risk factors that mediate this causal association. PMID:23398750

  8. Desenvolvimento cognitivo e de linguagem expressiva em um par de gêmeos dizigóticos: influência da síndrome de Down e da prematuridade associada ao muito baixo peso Expressive language and cognitive development in a dizygotic twin pair: influence of Down syndrome and prematurity combined with very low birth-weight

    Directory of Open Access Journals (Sweden)

    Fabíola Custódio Flabiano

    2009-01-01

    -weight on their development process during the sensorimotor period. Participated in this study a pair of VLBW preterm dizygotic male twins, one of whom presented Down syndrome. The subjects' initial chronological age was seven months and four days and their initial corrected age was four months and 21 days. The twins were born with 29 weeks of gestational age and weighting less than 1500g. The subjects were followed up during 12 months in 45-minute fortnight sessions, monthly recorded in video. The Protocol for Expressive Language and Cognitive Development Observation (PELCDO was used for data gathering and data analysis. Significant differences were observed between the twin brothers concerning expressive language and cognitive development. Although the twin without DS showed better performance, he still presented a relevant delay, considering the references for typically developing children. This finding evidences the influence of prematurity combined with very low birth weight on expressive language and cognitive development. The results found for the other twin suggest that DS led to a significant increase of this delay. DS and prematurity combined with very low birth weight are conditions that negatively interfered on expressive language and cognitive development of the twin pair studied.

  9. Sleep-EEG in dizygotic twins discordant for Williams syndrome.

    Science.gov (United States)

    Bódizs, Róbert; Gombos, Ferenc; Szocs, Katalin; Réthelyi, János M; Gerván, Patrícia; Kovács, Ilona

    2014-01-30

    Reports on twin pairs concordant and discordant for Williams syndrome were published before, but no study unravelled sleep physiology in these cases yet. We aim to fill this gap by analyzing sleep records of a twin pair discordant for Williams syndrome extending our focus on presleep wakefulness and sleep spindling. We performed multiplex ligation-dependent probe amplification of the 7q11.23 region of a 17 years old dizygotic opposite-sex twin pair discordant for Williams syndrome. Polysomnography of laboratory sleep at this age was analyzed and followed-up after 1.5 years by ambulatory polysomnography. Sleep stages scoring, EEG power spectra and sleep spindle analyses were carried out. The twin brother showed reduced levels of amplification for all of the probes in the 7q11.23 region indicating a typical deletion spanning at least 1.038 Mb between FKBP6 and CLIP2. The results of the twin sister showed normal copy numbers in the investigated region. Lower sleep times and efficiencies, as well as higher slow wave sleep percents of the twin brother were evident during both recordings. Roughly equal NREM, Stage 2 and REM sleep percents were found. EEG analyses revealed state and derivation-independent decreases in alpha power, lack of an alpha spectral peak in presleep wakefulness, as well as higher NREM sleep sigma peak frequency in the twin brother. Faster sleep spindles with lower amplitude and shorter duration characterized the records of the twin brother. Spectra show a striking reliability and correspondence between the two situations (laboratory vs. home records). Alterations in sleep and specific neural oscillations including the alpha/sigma waves are inherent aspects of Williams syndrome.

  10. Genetic and Environmental Basis in Phenotype Correlation Between Physical Function and Cognition in Aging Chinese Twins

    DEFF Research Database (Denmark)

    Xu, Chunsheng; Zhang, Dongfeng; Tian, Xiaocao

    2017-01-01

    for cognition with handgrip strength, FTSST, near visual acuity, and number of teeth lost. Cognitive function was genetically related to pulmonary function. The FTSST and cognition shared almost the same common environmental factors but only part of the unique environmental factors, both with negative......Although the correlation between cognition and physical function has been well studied in the general population, the genetic and environmental nature of the correlation has been rarely investigated. We conducted a classical twin analysis on cognitive and physical function, including forced...... and cognitive function. Bivariate analysis showed mildly positively genetic correlations between cognition and FEV1, r G = 0.23 [95% CI: 0.03, 0.62], as well as FVC, r G = 0.35 [95% CI: 0.06, 1.00]. We found that FTSST and cognition presented very high common environmental correlation, r C = -1.00 [95% CI: -1...

  11. Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins.

    Science.gov (United States)

    Wrede, Joanna E; Mengel-From, Jonas; Buchwald, Dedra; Vitiello, Michael V; Bamshad, Michael; Noonan, Carolyn; Christiansen, Lene; Christensen, Kaare; Watson, Nathaniel F

    2015-10-01

    Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Academic clinical research center. 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a "normal" (7-9 h/24) and "short" (sleeping twin. Fasting peripheral blood leukocyte DNA was assessed for mtDNA copy number via the n-fold difference between qPCR measured mtDNA and nuclear DNA creating an mtDNA measure without absolute units. We used generalized estimating equation linear regression models accounting for the correlated data structure to assess within-pair effects of sleep duration on mtDNA copy number. Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P sleep efficiency (β = 0.51; 95% CI 0.06, 0.95; P sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated with a decrease in mtDNA copy number of 0.51. Reduced sleep duration and sleep efficiency were associated with reduced mitochondrial DNA copy number in sleep duration discordant monozygotic twins offering a potential mechanism whereby short sleep impairs health and longevity through mitochondrial stress. © 2015 Associated Professional Sleep Societies, LLC.

  12. Separation surgery for total vertical craniopagus twins.

    Science.gov (United States)

    Goh, Keith Y C

    2004-08-01

    A pair of conjoined twins aged 11 months underwent investigations, followed by surgical separation in Singapore General Hospital in April 2001. They were joined at the skull vertex and facing in opposite directions. Radiological investigations including cerebral angiography, magnetic resonance imaging and computerized tomographic scans were performed, leading to the diagnosis of total vertical craniopagus. There were two separate brains, with separate arterial circulations, but with a common superior sagittal sinus. Tissue expanders were inserted in the subgaleal space for 6 months of scalp expansion prior to surgery. Pre-operative planning involved the use of virtual reality equipment and life-sized polymer models of the conjoined skulls and brains. Surgical separation of the twins was achieved after approximately 100 h of operating time, using intraoperative image guidance, microsurgical techniques and intraoperative neurophysiologic monitoring. Reconstruction of the dura, calvarium and scalp was performed with artificial dura, absorbable plates and split skin grafts. Postoperative complications included focal cortical infarction, meningitis, and hydrocephalus. Despite these complications, the twins recovered satisfactorily and were discharged to their home country within 6 months. The 3-month outcome was minor disability in one twin and severe developmental delays in the other. Separation surgery is possible for complex cranially-conjoined twins but requires detailed planning and extensive surgical management.

  13. Birth weight, sex, and celiac disease: a nationwide twin study

    Directory of Open Access Journals (Sweden)

    Kuja-Halkola R

    2017-11-01

    =1.11–2.02. However, the association was not significant in within-pair analyses for both dizygotic and monozygotic twins and for both sexes.Conclusion: This population-based study found that in male twins, higher birth weight was associated with higher risk of CD. However, when comparing discordant twin pairs in within-twin pair analyses, there was no statistically significant association between birth weight, intrauterine growth, and future risk of CD. Keywords: autoimmune, gestational age, gluten, registries, risk factors, twins

  14. Genetic Linkage and Association Analysis for Loneliness in Dutch Twin and Sibling Pairs Points to a Region on Chromosome 12q23–24

    NARCIS (Netherlands)

    Boomsma, D.I.; Cacioppo, J.T.; Slagboom, P.E.; Posthuma, D.

    2006-01-01

    We obtained evidence from a large study in Dutch twins (N = 8387) and siblings (N = 2295) that variation in loneliness has a genetic component. The heritability estimate for loneliness, which was assessed as an ordinal trait, was 40% and did not differ between males and females. There were 682

  15. Post-traumatic stress disorder and incidence of coronary heart disease: a twin study.

    Science.gov (United States)

    Vaccarino, Viola; Goldberg, Jack; Rooks, Cherie; Shah, Amit J; Veledar, Emir; Faber, Tracy L; Votaw, John R; Forsberg, Christopher W; Bremner, J Douglas

    2013-09-10

    The aim of this study was to determine whether post-traumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. It has long been hypothesized that PTSD increases the risk of CHD, but empirical evidence using objective measures is limited. We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [(13)N] ammonia positron emission tomography, including a stress total severity score and coronary flow reserve. A total of 562 twins (281 pairs) with a mean age of 42.6 years at baseline were included in this study. The incidence of CHD was more than double in twins with PTSD (22.6%) than in those without PTSD (8.9%; p Stress total severity score was significantly higher (+95%, p = 0.001) and coronary flow reserve was lower (-0.21, p = 0.02) in twins with PTSD than in those without PTSD, denoting worse myocardial perfusion. Associations were only mildly attenuated in 117 twin pairs discordant for PTSD. Among Vietnam-era veterans, PTSD is a risk factor for CHD. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  16. Pair Housing of Dairy Calves and Age at Pairing: Effects on Weaning Stress, Health, Production and Social Networks.

    Science.gov (United States)

    Bolt, Sarah L; Boyland, Natasha K; Mlynski, David T; James, Richard; Croft, Darren P

    2017-01-01

    The early social environment can influence the health and behaviour of animals, with effects lasting into adulthood. In Europe, around 60% of dairy calves are reared individually during their first eight weeks of life, while others may be housed in pairs or small groups. This study assessed the effects of varying degrees of social contact on weaning stress, health and production during pen rearing, and on the social networks that calves later formed when grouped. Forty female Holstein-Friesian calves were allocated to one of three treatments: individually housed (I, n = 8), pair-housed from day five (P5, n = 8 pairs), and pair-housed from day 28 (P28, n = 8 pairs). From day 48, calves were weaned by gradual reduction of milk over three days, and vocalisations were recorded as a measure of stress for three days before, during and after weaning. Health and production (growth rate and concentrate intakes) were not affected by treatment during the weaning period or over the whole study. Vocalisations were highest post-weaning, and were significantly higher in I calves than pair-reared calves. Furthermore, P28 calves vocalised significantly more than P5 calves. The social network of calves was measured for one month after all calves were grouped in a barn, using association data from spatial proximity loggers. We tested for week-week stability, social differentiation and assortment in the calf network. Additionally, we tested for treatment differences in: coefficient of variation (CV) in association strength, percentage of time spent with ex-penmate (P5 and P28 calves only) and weighted degree centrality (the sum of the strength of an individual's associations). The network was relatively stable from weeks one to four and was significantly differentiated, with individuals assorting based on prior familiarity. P5 calves had significantly higher CV in association strength than I calves in week one (indicating more heterogeneous social associations) but there were no

  17. Environmental manipulations alter age differences in attribution of incentive salience to reward-paired cues.

    Science.gov (United States)

    Anderson, Rachel I; Bush, Peter C; Spear, Linda P

    2013-11-15

    Cues repeatedly paired with rewards often themselves become imbued with enhanced motivational value, or incentive salience. During Pavlovian conditioned approach procedures, a cue repeatedly preceding reward delivery often elicits conditioned responses at either the reward delivery location ("goal-tracking") or the cue itself ("sign-tracking"). Sign-tracking behavior is thought to reflect the individual differences in attribution of incentive salience to reward-paired cues that may contribute to addiction vulnerability. Adolescent rats typically demonstrate less sign-tracking behavior than adult rats, a surprising finding given that adolescence is hypothesized to be a time of heightened addiction vulnerability. Given evidence that adult sign-tracking behavior can be influenced by environmental conditions, the present study compared the effects of isolate housing and food deprivation on expression of sign-tacking and goal-tracking behavior in adolescent and adult male rats across eight days of a Pavlovian conditioned approach procedure. Pair-housed adults exhibited more sign-tracking behavior than pair-housed adolescents; however, this age difference was not apparent in isolate-housed subjects. Adolescents often appeared more sensitive than adults to both food restriction- and isolate housing-induced changes in behavior, with food restriction promoting an increase in sign-tracking among isolate-housed adolescents and an increase in goal-tracking among pair-housed adolescents. For adults, food restriction resulted in a modest increase in overall expression of both sign- and goal-tracking behavior. To the extent that sign-tracking behavior reflects attribution of incentive salience to reward-paired cues, results from the present study provide evidence that reactivity to rewards during adolescence is strongly related to the nature of the surrounding environment. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Modeling age differences in effects of pair repetition and proactive interference using a single parameter.

    Science.gov (United States)

    Stephens, Joseph D W; Overman, Amy A

    2018-02-01

    In this article, we apply the REM model (Shiffrin & Steyvers, 1997) to age differences in associative memory. Using Criss and Shiffrin's (2005) associative version of REM, we show that in a task with pairs repeated across 2 study lists, older adults' reduced benefit of pair repetition can be produced by a general reduction in the diagnosticity of information stored in memory. This reduction can be modeled similarly well by reducing the overall distinctiveness of memory features, or by reducing the accuracy of memory encoding. We report a new experiment in which pairs are repeated across 3 study lists and extend the model accordingly. Finally, we extend the model to previously reported data using the same task paradigm, in which the use of a high-association strategy introduced proactive interference effects in young adults but not older adults. Reducing the diagnosticity of information in memory also reduces the proactive interference effect. Taken together, the modeling and empirical results reported here are consistent with the claim that some age differences that appear to be specific to associative information can be produced via general degradation of information stored in memory. The REM model provides a useful framework for examining age differences in memory as well as harmonizing seemingly conflicting prior modeling approaches for the associative deficit. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  19. The Heritability of Prostate Cancer in the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    von Bornemann Hjelmborg, Jacob; Scheike, Thomas; Holst, Klaus

    2014-01-01

    Background: Prostate cancer is thought to be the most heritable cancer, although little is known about how this genetic contribution varies across age. Methods: To address this question, we undertook the world’s largest prospective study in the Nordic Twin Study of Cancer cohort, including 18...... risk and liability. Results: The cumulative risk of prostate cancer was similar to that of the background population. The cumulative risk for twins whose co-twin was diagnosed with prostate cancer was greater for MZ than for DZ twins across all ages. Among concordantly affected pairs, the time between...... diagnoses was significantly shorter for MZ than DZ pairs (median 3.8 versus 6.5 years, respectively). Genetic differences contributed substantially to variation in both the risk and the liability (heritability=58% (95% CI 52%–63%) of developing prostate cancer. The relative contribution of genetic factors...

  20. Power Estimation for Gene-Longevity Association Analysis Using Concordant Twins

    DEFF Research Database (Denmark)

    Tan, Qihua; Zhao, Jing Hua; Kruse, Torben A

    2014-01-01

    Statistical power is one of the major concerns in genetic association studies. Related individuals such as twins are valuable samples for genetic studies because of their genetic relatedness. Phenotype similarity in twin pairs provides evidence of genetic control over the phenotype variation...... in a population. The genetic association study on human longevity, a complex trait that is under control of both genetic and environmental factors, has been confronted by the small sample sizes of longevity subjects which limit statistical power. Twin pairs concordant for longevity have increased probability...... an approximate of 2- to 3-fold increase in sample sizes needed for longevity cutoff at age 90 as compared with that at age 95. Overall, our results showed high value of twins in genetic association studies on human longevity....

  1. Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins

    DEFF Research Database (Denmark)

    Wrede, Joanna E; Mengel-From, Jonas; Buchwald, Dedra

    2015-01-01

    STUDY OBJECTIVES: Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins...... structure to assess within-pair effects of sleep duration on mtDNA copy number. MEASUREMENTS AND RESULTS: Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P sleep efficiency (β = 0.51; 95% CI 0.......06, 0.95; P DNA copy number within twin pairs. Thus every 1-minute decrease in actigraphy-defined sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated...

  2. Genetic susceptibility to bilateral tinnitus in a Swedish twin cohort.

    Science.gov (United States)

    Maas, Iris Lianne; Brüggemann, Petra; Requena, Teresa; Bulla, Jan; Edvall, Niklas K; Hjelmborg, Jacob V B; Szczepek, Agnieszka J; Canlon, Barbara; Mazurek, Birgit; Lopez-Escamez, Jose A; Cederroth, Christopher R

    2017-09-01

    Genetic contributions to tinnitus have been difficult to determine due to the heterogeneity of the condition and its broad etiology. Here, we evaluated the genetic and nongenetic influences on self-reported tinnitus from the Swedish Twin Registry (STR). Cross-sectional data from the STR was obtained. Casewise concordance rates (the risk of one twin being affected given that his/her twin partner has tinnitus) were compared for monozygotic (MZ) and dizygotic (DZ) twin pairs (N = 10,464 concordant and discordant twin pairs) and heritability coefficients (the proportion of the total variance attributable to genetic factors) were calculated using biometrical model fitting procedures. Stratification of tinnitus cases into subtypes according to laterality (unilateral versus bilateral) revealed that heritability of bilateral tinnitus was 0.56; however, it was 0.27 for unilateral tinnitus. Heritability was greater in men (0.68) than in women (0.41). However, when female pairs younger than 40 years of age were selected, heritability of 0.62 was achieved with negligible effects of shared environment. Unlike unilateral tinnitus, bilateral tinnitus is influenced by genetic factors and might constitute a genetic subtype. Overall, our study provides the initial evidence for a tinnitus phenotype with a genetic influence.Genet Med advance online publication 23 March 2017.

  3. Effects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins.

    Science.gov (United States)

    Ferraresi, Cleber; Bertucci, Danilo; Schiavinato, Josiane; Reiff, Rodrigo; Araújo, Amélia; Panepucci, Rodrigo; Matheucci, Euclides; Cunha, Anderson Ferreira; Arakelian, Vivian Maria; Hamblin, Michael R; Parizotto, Nivaldo; Bagnato, Vanderlei

    2016-10-01

    The aim of this study was to verify how a pair of monozygotic twins would respond to light-emitting diode therapy (LEDT) or placebo combined with a strength-training program during 12 weeks. This case-control study enrolled a pair of male monozygotic twins, allocated randomly to LEDT or placebo therapies. Light-emitting diode therapy or placebo was applied from a flexible light-emitting diode array (λ = 850 nm, total energy = 75 J, t = 15 seconds) to both quadriceps femoris muscles of each twin immediately after each strength training session (3 times/wk for 12 weeks) consisting of leg press and leg extension exercises with load of 80% and 50% of the 1-repetition maximum test, respectively. Muscle biopsies, magnetic resonance imaging, maximal load, and fatigue resistance tests were conducted before and after the training program to assess gene expression, muscle hypertrophy and performance, respectively. Creatine kinase levels in blood and visual analog scale assessed muscle damage and delayed-onset muscle soreness, respectively, during the training program. Compared with placebo, LEDT increased the maximal load in exercise and reduced fatigue, creatine kinase, and visual analog scale. Gene expression analyses showed decreases in markers of inflammation (interleukin 1β) and muscle atrophy (myostatin) with LEDT. Protein synthesis (mammalian target of rapamycin) and oxidative stress defense (SOD2 [mitochondrial superoxide dismutase]) were up-regulated with LEDT, together with increases in thigh muscle hypertrophy. Light-emitting diode therapy can be useful to reduce muscle damage, pain, and atrophy, as well as to increase muscle mass, recovery, and athletic performance in rehabilitation programs and sports medicine.

  4. Longitudinal weight differences, gene expression, and blood biomarkers in BMI discordant identical twins

    Science.gov (United States)

    van Dongen, Jenny; Willemsen, Gonneke; Heijmans, Bastiaan T.; Neuteboom, Jacoline; Kluft, Cornelis; Jansen, Rick; Penninx, Brenda W.J.; Slagboom, P. Eline; de Geus, Eco J.C.; Boomsma, Dorret I.

    2015-01-01

    Background BMI discordant monozygotic (MZ) twins allows an examination of the causes and consequences of adiposity in a genetically controlled design. Few studies have examined longitudinal BMI discordance in MZ pairs. Objectives To study the development over time of BMI discordance in adolescent and adult MZ twin pairs, and to examine lifestyle, metabolic, inflammatory, and gene expression differences associated with concurrent and long-term BMI discordance in MZ pairs. Subjects/Methods BMI data from 2775 MZ twin pairs, collected in eight longitudinal surveys and a biobank project between 1991 and 2011, were analyzed to characterize longitudinal discordance. Lifestyle characteristics were compared within discordant pairs (ΔBMI ≥ 3 kg/m2) and biomarkers (lipids, glucose, insulin, CRP, fibrinogen, IL-6, TNF-α and sIL-6R and liver enzymes AST, ALT and GGT) and gene expression were compared in peripheral blood from discordant pairs who participated in the NTR biobank project. Results The prevalence of discordance ranged from 3.2% in 1991 (mean age=17, SD=2.4) to 17.4% (N=202 pairs) in 2009 (mean age=35, SD=15), and was 16.5% (N=174) among pairs participating in the biobank project (mean age=35, SD=12). Of 699 MZ with BMI data from 3-5 time points, 17 pairs (2.4%) were long-term discordant (at all available time points; mean follow-up range=6.4 years). Concurrently discordant pairs showed significant differences in self-ratings of which twin eats most (p=2.3×10−13), but not in leisure time exercise activity (p=0.28) and smoking (p>0.05). Ten out of 14 biomarkers showed significantly more unfavorable levels in the heavier of twin of the discordant pairs (p-values BMI discordance is uncommon in adolescent identical pairs but increases with higher pair-mean of BMI at older ages, although long-term BMI discordance is rare. In discordant pairs, the heavier twin had a more unfavorable blood biomarker profile than the genetically matched leaner twin, in support of

  5. Morphologies and ages of star cluster pairs and multiplets in the Small Magellanic Cloud

    Science.gov (United States)

    de Oliveira, M. R.; Dutra, C. M.; Bica, E.; Dottori, H.

    2000-10-01

    An isophotal atlas of 75 star cluster pairs and multiplets in the Small Magellanic Cloud is presented, comprising 176 objects. They are concentrated in the SMC main body. The isophotal contours were made from Digitized Sky Survey* images and showed relevant structural features possibly related to interactions in about 25% of the sample. Previous N-body simulations indicate that such shapes could be due to tidal tails, bridges or common envelopes. The diameter ratio between the members of a pair is preferentially in the range 1 - 2, with a peak at 1. The projected separation is in the range ~ 3 - 22 pc with a pronounced peak at ~ 13 pc. For 91 objects it was possible to derive ages from Colour-Magnitude Diagrams using the OGLE-II photometric survey. The cluster multiplets in general occur in OB stellar associations and/or HII region complexes. This indicates a common origin and suggests that multiplets coalesce into pairs or single clusters in a short time scale. Pairs in the SMC appear to be mostly coeval and consequently captures are a rare phenomenon. We find evidence that star cluster pairs and multiplets may have had an important role in the dynamical history of clusters presently seen as large single objects. The images in this study are based on photographic data obtained using the UK Schmidt Telescope, which was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council, until 1988 June, and thereafter by the Anglo-Australian Observatory. Original plate material is copyright by the Royal Observatory Edinburgh and the Anglo-Australian Observatory. The plates were processed into the present compressed digital form with their permission. The Digitized Sky Survey was produced at the Space Telescope Science Institute under US Government grant NAG W-2166.

  6. Social activity and healthy aging

    DEFF Research Database (Denmark)

    McGue, Matt; Christensen, Kaare

    2007-01-01

    with late-life physical functioning, cognitive functioning, and depression symptomatology using data from 1112 pairs of like-sex twins who participated in the Longitudinal Study of Aging Danish Twins. Consistent with previous research, we found that social activity was significantly correlated with overall...... activity did not predict change in functioning and in monozygotic twin pairs discordant on level of social activity, the more socially active twin was not less susceptible to age decreases in physical and cognitive functioning and increases in depression symptomatology than the less socially active twin......Although social and intellectual engagement have been consistently associated with late-life functioning, rather than true causation, these associations may reflect the experiential choices of high functioning individuals (i.e., selection effects). We investigated the association of social activity...

  7. Longitudinal genetic analysis of brain volumes in normal elderly male twins

    OpenAIRE

    Lessov-Schlaggar, Christina N.; Hardin, Jill; DeCarli, Charles; Krasnow, Ruth E.; Reed, Terry; Wolf, Philip A.; Swan, Gary E.; Carmelli, Dorit

    2010-01-01

    This study investigated the role of genetic and environmental influences on individual differences in brain volumes measured at two time points in normal elderly males from the National Heart, Lung, and Blood Institute Twin Study. The MRI scans were conducted four years apart on 33 monozygotic and 33 dizygotic male twin pairs, aged 68 to 77 years when first scanned. Volumetric measures of total brain and total cerebrospinal fluid were significantly heritable at baseline (over 70%). For both v...

  8. Ecosensitivity and genetic polymorphism of somatic traits in the perinatal development of twins.

    Science.gov (United States)

    Waszak, Małgorzata; Cieślik, Krystyna; Skrzypczak-Zielińska, Marzena; Szalata, Marlena; Wielgus, Karolina; Kempiak, Joanna; Bręborowicz, Grzegorz; Słomski, Ryszard

    2016-04-01

    In view of criticism regarding the usefulness of heritability coefficients, the aim of this study was to analyze separately the information on genetic and environmental variability. Such an approach, based on the normalization of trait's variability for its value, is determined by the coefficients of genetic polymorphism (Pg) and ecosensitivity (De). The studied material included 1263 twin pairs of both sexes (among them 424 pairs of monozygotic twins and 839 pairs of dizygotic twins) born between the 22nd and 41st week of gestation. Variability of six somatic traits was analyzed. The zygosity of same-sex twins was determined based on the polymorphism of DNA from lymphocytes of the umbilical cord blood, obtained at birth. The coefficients of genetic polymorphism and ecosensitivity for analyzed traits of male and female twins born at various months of gestation were calculated. Our study revealed that a contribution of the genetic component predominated over that of the environmental component in determining the phenotypic variability of somatic traits of newborns from twin pregnancies. The genetically determined phenotypic variability in male twins was greater than in the females. The genetic polymorphism and ecosensitivity of somatic traits were relatively stable during the period of fetal ontogeny analyzed in this study. Only in the case of body weight, a slight increase in the genetic contribution of polygenes to the phenotypic variance could be observed with gestational age, along with a slight decrease in the influence of environmental factors. Copyright © 2015 Elsevier GmbH. All rights reserved.

  9. Cohort Profile : The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry)

    NARCIS (Netherlands)

    Gatz, Margaret; Harris, Jennifer R.; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L.; Snieder, Harold; Spiro, Avron; Butler, David A.

    The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved

  10. Twin’s birth-order differences in height and body mass index from birth to old age: a pooled study of 26 twin cohorts participated in the CODATwins project

    Science.gov (United States)

    Yokoyama, Yoshie; Jelenkovic, Aline; Sund, Reijo; Sung, Joohon; Hopper, John L; Ooki, Syuichi; Heikkilä, Kauko; Aaltonen, Sari; Tarnoki, Adam D; Tarnoki, David L; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos CEM; Saudino, Kimberly J; Cutler, Tessa L; Nelson, Tracy L; Whitfield, Keith E; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; He, Mingguang; Ding, Xiaohu; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Jeong, Hoe-Uk; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Burt, S Alexandra; Klump, Kelly L; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas Sevenius; Craig, Jeffrey M; Saffery, Richard; Ji, Fuling; Ning, Feng; Pang, Zengchang; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Magnusson, Patrik KE; Pedersen, Nancy L; Aslan, Anna K Dahl; Tynelius, Per; Haworth, Claire MA; Plomin, Robert; Rebato, Esther; Rose, Richard J; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Sørensen, Thorkild IA; Boomsma, Dorret I; Kaprio, Jaakko; Silventoinen, Karri

    2016-01-01

    We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were not statistically significant anymore. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first and second born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI. PMID:26996222

  11. Twin-twin transfusion syndrome - diagnosis and prognosis

    Directory of Open Access Journals (Sweden)

    Hajrić-Egić Amira

    2003-01-01

    Full Text Available Twin-twin transfusion syndrome is a serious complication of monozygotic, monochorionic, diamniotic twins resulting from transplacental vascular communications. In this syndrome blood is thought to be shunted from one twin - donor,who develops anaemia,growth retardation and oligoamnios, to the other twin - recipient,who becomes plethoric,macrosomic and develops polyhydroamnios. The incidence of twin-twin transfusion syndrome ranges from 5-15% of all twin pregnancies. If this condition develops in the second trimester, it is usually associated with spontaneous abortion and death of one or both fetuses before viability. Developing the syndrome in the third trimester has better perinatal outcome. Mortality rates ranging from 56%-100%, depending on gestational age and severity of the syndrome. The ultrasound criterias for diagnosis, in this study,were the presence of twins of the same sex with discordant growth, with oligohydroamnios in one twin sac and polyhydroamnios in the other one, one placenta and thin membrane between twins. The present study shows clinical course of 14 cases and value of Doppler ultrasound to analyze the usefulness of umbilical artery blood flow velocimetry for predicting the risk of twin-twin transfusion syndrome. 14 twin pregnancies with twin-twin transfusion syndrome were diagnosed during the last four years period and prospectivelly followed. 9 cases were diagnosed before the completion od 28 weeks of gestation.The mean gestational age was 21,6_+4,2 weeks at diagnosis and 23,2+_3,6 weeks at delivery. 5 cases were diagnosed after 28 weeks of gestation. The mean gestational age in this group was 29,6+_2,1 weeks at diagnosis and 33+_3,3 weeks at delivery. The survival rate in this study was 29%(8/28.9 cases ended in spontaneous abortion between 18th and 27th weeks of pregnancy (table 1 and 5 in premature labor (table 2.There were 7 intrauterine death (5 at admission and 2 few days after admission and 13 neonatal deaths

  12. The age-dependency of genetic and environmental influences on serum cytokine levels : A twin study

    NARCIS (Netherlands)

    Sas, Arthur A.; Jamshidi, Yalda; Zheng, Dongling; Wu, Ting; Korf, Jakob; Alizadeh, Behrooz Z.; Snieder, Harold; Spector, Timothy D.

    2012-01-01

    Previous epidemiologic studies have evaluated the use of immunological markers as possible tools for measuring ageing and predicting age-related pathology. The importance of both genetic and environmental influences in regulation of these markers has been emphasized. In order to further evaluate

  13. Monozygotic twins with CAPN5 autosomal dominant neovascular inflammatory vitreoretinopathy

    Directory of Open Access Journals (Sweden)

    Rowell HA

    2012-12-01

    Full Text Available Hannah A Rowell,1,2 Alexander G Bassuk,3,4 Vinit B Mahajan1,21Omics Laboratory, 2Department of Ophthalmology and Visual Sciences, 3Department of Pediatrics, 4Department of Neurology, University of Iowa, Iowa City, IA, USABackground: The purpose of this study was to describe the clinical findings in a set of monozygotic twins with autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV over a 23-year period.Methods: A pair of female twins were examined between 26 and 49 years of age. The concordance and discordance of their clinical features were determined. The CAPN5 gene was sequenced using genomic DNA.Results: Both twins of an affected father demonstrated Stage I ADNIV with mild vitreous cells and a negative b-wave on electroretinography. Genetic analysis confirmed a guanine to thymine nucleotide (c.728G>T, pArg243Leu mutation in the CAPN5 gene. Over the course of 23 years, each twin progressed to stage III disease, showing posterior uveitis, cystoid macular edema, intraocular fibrosis, early retinal neovascularization, retinal degeneration, and cataract. Disease progression varied moderately between each twin and was asymmetrical between eyes. Twin A had 20/70 and 20/125 in the right and left eye, respectively, and underwent vitrectomy surgery and intravitreal injections with bevacizumab for recurrent cystoid macular edema. Twin B maintained 20/20 and 20/40 in the right and left eye, respectively without intervention.Conclusion: There was asymmetry between the eyes and some discordance in the rate of disease progression in these monozygotic twins with ADNIV. The overall high disease concordance suggests genetic factors play a major role in clinical manifestations in CAPN5 vitreoretinopathy.Keywords: autosomal dominant neovascular inflammatory vitreoretinopathy, ADNIV, CAPN5, calpain-5, monozygotic twins

  14. A population-based study of gastroesophageal reflux disease and sleep problems in elderly twins.

    Directory of Open Access Journals (Sweden)

    Anna Lindam

    Full Text Available BACKGROUND & AIMS: Previous studies indicate an association between sleep problems and gastroesophageal reflux disease (GERD. Although both these conditions separately have moderate heritabilities, confounding by genetic factors has not previously been taken into account. This study aimed to reveal the association between sleep problems and GERD, while adjusting for heredity and other potential confounding factors. METHODS: This cross-sectional population-based study included all 8,014 same-sexed twins of at least 65 years of age and born in Sweden between 1886 and 1958, who participated in telephone interviews in 1998-2002. Three logistic regression models were used 1 external control analysis, 2 within-pair co-twin analysis with dizygotic (DZ twin pairs discordant for GERD, and 3 within-pair co-twin analysis with monozygotic (MZ twin pairs discordant for GERD. Odds ratios (ORs with 95% confidence intervals (CIs were calculated and adjusted for established risk factors for GERD, i.e. sex, age, body mass index (BMI, tobacco smoking, and educational level. RESULTS: A dose-response association was identified between increasing levels of sleep problems and GERD in the external control analysis. Individuals who often experienced sleep problems had a two-fold increased occurrence of GERD compared to those who seldom had sleep problems (OR 2.0, 95% CI 1.8-2.4. The corresponding association was of similar strength in the co-twin analysis including 356 DZ pairs (OR 2.2, 95% CI 1.6-3.4, and in the co-twin analysis including 210 MZ pairs (OR 1.5, 95% CI 0.9-2.7. CONCLUSION: A dose-dependent association between sleep problems and GERD remains after taking heredity and other known risk factors for GERD into account.

  15. Verification of self-report of zygosity determined via DNA testing in a subset of the NAS-NRC twin registry 40 years later.

    Science.gov (United States)

    Reed, Terry; Plassman, Brenda L; Tanner, Caroline M; Dick, Danielle M; Rinehart, Shannon A; Nichols, William C

    2005-08-01

    The National Academy of Sciences -- National Research Council (NAS-NRC) twin panel, created nearly 50 years ago, had twin zygosity determined primarily via a similarity questionnaire that has been estimated to correctly classify at least 95% of twins. In the course of a study on the genetics of healthy ageing in the NAS-NRC twins, DNA was collected for genome-wide scanning and zygosity confirmation was examined in 343 participating pairs. The sample was supplemented from two other studies using NAS-NRC twins where one or both co-twins were suspected to have Alzheimer disease or another dementia, or Parkinson's disease. Overall 578 twin pairs with DNA were analyzed. Zygosity assignment for 96.8% (519/536) was confirmed via questionnaire. Among 42 pairs whose questionnaire responses were inconclusive for assigning zygosity, 50% were found to be monozygous (MZ) and 50% were dizygous (DZ). There was some evidence for greater misclassification of presumed DZ pairs in the healthy ageing study where participation favored pairs who were similar in having a favorable health history and willingness to volunteer without any element of perceived risk for a specific disease influencing participation.

  16. Hallux Valgus, By Nature or Nurture? A Twin Study.

    Science.gov (United States)

    Munteanu, Shannon E; Menz, Hylton B; Wark, John D; Christie, Jemma J; Scurrah, Katrina J; Bui, Minh; Erbas, Bircan; Hopper, John L; Wluka, Anita E

    2017-09-01

    To evaluate the contributions of shared but unmeasured genetic and environmental factors to hallux valgus (HV). Between 2011 and 2012, 74 monozygotic (MZ) and 56 dizygotic (DZ) female twin pairs self-reported HV and putative risk factors, including footwear use across their lifespan. Estimates of casewise concordance (P C ), correlation (ρ), and odds ratios (ORs) were calculated, adjusting for age and other risk factors, and compared between MZ and DZ pairs using logistic regression, generalized estimating equations, and a maximum likelihood-based method, respectively. A total of 70 participants (27%) reported HV, with 12 MZ and 7 DZ pairs being concordant. After adjusting for age, twins were correlated (ρ = 0.27 [95% confidence interval (95% CI) 0.08, 0.46]) and concordant (P C  = 0.45 [95% CI 0.29, 0.61]; mean age 58 years), with no difference between MZ and DZ pairs (P = 0.7). HV was associated with regularly wearing footwear with a constrictive toe-box during the fourth decade (adjusted OR 2.73 [95% CI 1.12, 6.67]). This risk factor was correlated in MZ (ρ = 0.38 [95% CI 0.15, 0.60]) but not DZ (ρ = -0.20 [95% CI -0.43, 0.03]) pairs. These correlations were significantly different (P = 0.002). Twins are correlated for HV, but we found no evidence that correlation was due to shared genetic factors. We identified an environmental risk factor, footwear with a constrictive toe-box, that is not shared to the same extent by MZ and DZ pairs, contrary to the assumption of the classic twin model. Footwear, and possibly genetic factors and unknown shared environmental factors, could contribute to developing HV. © 2016, American College of Rheumatology.

  17. 'Biracial'-Looking Twins: A New Twin Type?/Twin Research: Twins with Cystic Teratomas; Sleep Quality and Body Mass Index; Previable Membrane Rupture/Print and Online Reports: Twins Born to a Sister Surrogate; NASA Twin Study; African-Cosmopolitan Twin Fashion Inspirations; Triplet Hockey Stars.

    Science.gov (United States)

    Segal, Nancy L

    2017-06-01

    Dizygotic (DZ) co-twins born to mothers and fathers from different racial or ethnic backgrounds often resemble one parent much more than the other. As such, these pairs comprise a unique subset of twins for investigating how others' responses to their different looks may affect their personalities and self-esteem. This article describes some of these twin pairs and some challenges of raising them, and suggests ways they may be used in research. Next, recent twin research on cystic teratomas, relations between sleep quality and body mass index, and previable membrane rupture is described. The final section concerns twins, twin studies, and related events in the media, namely: twins born to a sister surrogate, the NASA twin investigation, inspiring African-Cosmopolitan twins in fashion, and triplet Hockey Stars.

  18. DNA Methylation and All-Cause Mortality in Middle-Aged and Elderly Danish Twins

    DEFF Research Database (Denmark)

    Svane, Anne Marie; Soerensen, Mette; Lund, Jesper

    2018-01-01

    Several studies have linked DNA methylation at individual CpG sites to aging and various diseases. Recent studies have also identified single CpGs whose methylation levels are associated with all-cause mortality. In this study, we perform an epigenome-wide study of the association between CpG met...

  19. Twin pregnancy

    DEFF Research Database (Denmark)

    Sperling, Lene; Tabor, A

    2001-01-01

    Determination of chorionicity is one of the most important issues in the management of twin pregnancy. Modern ultrasound equipment has made it possible to accurately assess placentation already in the first trimester with the lambda sign. With regard to prenatal diagnosis, it is important to know...... for clinicians caring for twin pregnancies....

  20. Long-term leisure time physical activity and properties of bone: a twin study.

    Science.gov (United States)

    Ma, Hongqiang; Leskinen, Tuija; Alen, Markku; Cheng, Sulin; Sipilä, Sarianna; Heinonen, Ari; Kaprio, Jaakko; Suominen, Harri; Kujala, Urho M

    2009-08-01

    Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50-74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-sectional area (intrapair difference: 8%, p = 0.006), thicker cortex (12%, p = 0.003), and greater moment of inertia (I(max), 20%, p = 0.024) at the tibia shaft than their inactive co-twins. At the distal tibia, trabecular BMD (12%, p = 0.050) and compressive strength index (18%, p = 0.038) were also higher in physically active MZ pair members than their inactive co-twins. The trends were similar, but less consistently so, in DZ pairs as in MZ pairs. Our genetically controlled study design shows that LTPA during adulthood strengthens bones in a site-specific manner, that is, the long bone shaft has a thicker cortex, and thus higher bending strength, whereas the distal bone has higher trabecular density and compressive strength. These results suggest that LTPA has a potential causal role in decreasing the long-term risk of osteoporosis and thus preventing osteoporotic fractures.

  1. Twin-singleton differences in cognitive abilities in a sample of Africans in Nigeria.

    Science.gov (United States)

    Hur, Yoon-Mi; Lynn, Richard

    2013-08-01

    Recent studies comparing cognitive abilities between contemporary twins and singletons in developed countries have suggested that twin deficits in cognitive abilities no longer exist. We examined cognitive abilities in a sample of twins and singletons born recently in Nigeria to determine whether recent findings can be replicated in developing countries. Our sample consisted of 413 pairs of twins and 280 singletons collected from over 45 public schools in Abuja and its neighboring states in Nigeria. The ages of twins and singletons ranged from 9 to 20 years with a mean (SD) of 14.6 years (2.2 years) for twins and 16.1 years (1.8 years) for singletons. Zygosity of the same-sex twins was determined by analysis of 16 deoxyribonucleic acid markers. We asked participants to complete a questionnaire booklet that included Standard Progressive Matrices-Plus Version (SPM+), Mill-Hill Vocabulary Scale (MHV), Family Assets Questionnaire, and demographic questions. The data were corrected for sex and age and then analyzed using maximum likelihood model-fitting analysis. Although twins and singletons were comparable in family social class indicators, singletons did better than twins across all the tests (d = 0.10 to 0.35). The average of d for SPM+ total [0.32; equivalent to 4.8 Intelligence Quotient (IQ) points] and d for MHV (0.24; equivalent to 3.6 IQ points) was 0.28 (equivalent to 4.2 IQ points), similar to the twin-singleton gap found in old cohorts in developed countries. We speculate that malnutrition, poor health, and educational systems in Nigeria may explain the persistence of twin deficits in cognitive abilities found in our sample.

  2. Genetic and environmental factors in alexithymia: A population-based study of 8.785 Danish twin pairs

    DEFF Research Database (Denmark)

    Jørgensen, Michael Martini; Zachariae, Robert; Skytthe, Axel

    2007-01-01

    by shared (12-20%) and nonshared environmental effects (50-56%). CONCLUSION: The results from this large population-based sample suggest that genetic factors have a noticeable and similar impact on all facets of alexithymia. While the results suggested a moderate influence of shared environmental factors......BACKGROUND: The role of genetic and environmental factors for developing alexithymia is still unclear, and the aim of this study was to examine these factors in a large population-based sample of twins. METHODS: The Toronto Alexithymia Scale-20 (TAS-20) was included in a mail survey of 46...... modeling of the noncategorical data, an ACE model including additive genetic, shared environmental and nonshared environmental effects, provided the best fit for all three facets of alexithymia as well as total alexithymia scores, with heritabilities of 30-33% and the remaining variance being explained...

  3. Bruxism Is Associated With Nicotine Dependence: A Nationwide Finnish Twin Cohort Study

    Science.gov (United States)

    Ahlberg, J.; Hublin, C.; Broms, U.; Madden, P. A. F.; Könönen, M.; Koskenvuo, M.; Lobbezoo, F.; Kaprio, J.

    2010-01-01

    Objectives: To investigate the association of smoking with bruxism while controlling for genetic and environmental factors using a co-twin-control design. Especially, the role of nicotine dependence was studied in this context. Methods: The material derives from the Finnish Twin Cohort consisting of 12,502 twin individuals who responded to a questionnaire in 1990 (response rate of 77%). All were born in 1930–1957, the mean age being 44 years. The questionnaire covered 103 multiple choice questions, 7 dealing with tobacco use and 22 with sleep and vigilance matters, including perceived bruxism. In addition, a subsample derived from the Nicotine Addiction Genetics Finland Study containing 445 twin individuals was studied. Results: In age- and gender-controlled multinomial logistic regression, both monthly and rarely reported bruxism associated with both current cigarette smoking (odds ratio [OR] = 1.74 and 1.64) and former cigarette smoking (OR = 1.64 and 1.47). Weekly bruxism associated with current smoking (OR = 2.85). Current smokers smoking 20 or more cigarettes a day reported weekly bruxism more likely (OR = 1.61–1.97) than those smoking less. Among twin pairs (N = 142) in which one twin was a weekly bruxer and the cotwin a never bruxer, there were 13 monozygotic pairs in which one twin was a current smoker and the other twin was not. In all cases, the bruxer was the smoker (p = .0003). Nicotine dependence associated significantly with bruxism. Conclusions: Our twin study provides novel evidence for a possible causal link between tobacco use and bruxism among middle-aged adults. Nicotine dependence may be a significant predisposing factor for bruxism. PMID:21041838

  4. Monozygotic twin pairs discordant for Hashimoto's thyroiditis share a high proportion of thyroid peroxidase autoantibodies to the immunodominant region A. Further evidence for genetic transmission of epitopic “fingerprints”

    DEFF Research Database (Denmark)

    Brix, Thomas Heiberg; Hegedüs, Laszlo; Gardas, Andrzej

    2010-01-01

    Thyroid peroxidase antibodies (TPOAbs) in patients with Hashimoto's thyroiditis (HT) predominantly react with two immunodominant regions (IDR-A, IDR-B). Theoretically, as shown for the level of TPOAbs, the autoantibody epitopic recognition of the IDRs could be under genetic control. To examine this......, we compared the distribution of TPOAb epitopic fingerprints between healthy monozygotic (MZ) co-twins and siblings to patients with clinically overt HT with a control group of euthyroid subjects, matched for sex and age, but without autoimmune thyroid disease (AITD) among their first-degree relatives...

  5. The similarity of twin brains; Die Aehnlichkeit von Zwillingsgehirnen

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, A.; Knauth, M.; Stippich, C.; Sartor, K. [Abt. Neuroradiologie, Univ. Heidelberg (Germany); Weisbrod, M. [Sektion Experimentelle Psychopathologie, Psychiatrische Klinik Univ. Heidelberg (Germany)

    2001-06-01

    To test the assumption underlying every morphometric twin study that the brains of monozygotic twins are almost identical. Methods: High resolution MRI of the neurocranium of 26 monozygotic twin pairs were acquired and the volumes of 36 cerebral structures were measured. The same twins served as control group after rear-ranging them into non-related pairs of same sex and matching them for age, body height and body weight. Results: For most of the examined structures the correlations within the twins were significant (R = 0,97-0,59). Except for total forebrain volume the controls showed no significant similarity. Conclusions: For almost every measured cerebral structure the assumption, that significant similarities exist between healthy monozygotic twins is correct. Therefore discordant monozygotic twins represent an excellent sample when investigating cerebral correlates of neurologic and psychiatric disorders. (orig.) [German] Pruefung der Grundannahme hirnmorphologischer Zwillingsstudien, dass die Gehirne eineiiger Zwillinge signifikant aehnlich sind. Methode: Hochaufloesende MRT-Datensaetze der Gehirne von 26 gesunden eineiigen Zwillingspaaren dienten als Grundlage der volumetrischen Vermessung von insgesamt 36 zerebralen Strukturen. Als Kontrollkollektiv wurden neue, nicht verwandte, aber gleichgeschlechtliche und nach Alter, Koerpergroesse und Koerpergewicht sehr aehnliche Paare gebildet. Ergebnisse: Fuer Hemisphaerenvolumen, graue und weisse Substanz des Frontal- und Temporallappens (R = 0,97-0,59) sowie fuer zahlreiche subkortikale Strukturen (R = 0,80-0,41) zeigten sich signifikante (p < 0,05) Korrelationen zwischen den Zwillingspaaren. Ausser fuer Grosshirnvolumen fanden sich bei den Kontrollpaaren keine signifikanten Aehnlichkeiten. Schlussfolgerung: Fuer die meisten der vermessenen zerebralen Areale ist die Annahme richtig, dass die Gehirne eineliger Zwillinge deutlich aehnlicher sind als die Gehirne nicht verwandter Personen. Bei der Suche nach

  6. Physical activity, fitness, glucose homeostasis, and brain morphology in twins.

    Science.gov (United States)

    Rottensteiner, Mirva; Leskinen, Tuija; Niskanen, Eini; Aaltonen, Sari; Mutikainen, Sara; Wikgren, Jan; Heikkilä, Kauko; Kovanen, Vuokko; Kainulainen, Heikki; Kaprio, Jaakko; Tarkka, Ina M; Kujala, Urho M

    2015-03-01

    The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

  7. Use of a twin dataset to identify AMD-related visual patterns controlled by genetic factors

    Science.gov (United States)

    Quellec, Gwénolé; Abràmoff, Michael D.; Russell, Stephen R.

    2010-03-01

    The mapping of genotype to the phenotype of age-related macular degeneration (AMD) is expected to improve the diagnosis and treatment of the disease in a near future. In this study, we focused on the first step to discover this mapping: we identified visual patterns related to AMD which seem to be controlled by genetic factors, without explicitly relating them to the genes. For this purpose, we used a dataset of eye fundus photographs from 74 twin pairs, either monozygotic twins, who have the same genotype, or dizygotic twins, whose genes responsible for AMD are less likely to be identical. If we are able to differentiate monozygotic twins from dizygotic twins, based on a given visual pattern, then this pattern is likely to be controlled by genetic factors. The main visible consequence of AMD is the apparition of drusen between the retinal pigment epithelium and Bruch's membrane. We developed two automated drusen detectors based on the wavelet transform: a shape-based detector for hard drusen, and a texture- and color- based detector for soft drusen. Forty visual features were evaluated at the location of the automatically detected drusen. These features characterize the texture, the shape, the color, the spatial distribution, or the amount of drusen. A distance measure between twin pairs was defined for each visual feature; a smaller distance should be measured between monozygotic twins for visual features controlled by genetic factors. The predictions of several visual features (75.7% accuracy) are comparable or better than the predictions of human experts.

  8. Twin birth order, birthweight and birthweight discordance: any relationship

    Directory of Open Access Journals (Sweden)

    Onyiriuka A.N.

    2010-12-01

    Full Text Available Background: It is widely believed that in twin pairs, at birth, the first-born weigh more than the second-born but this concept has been challenged. Objective: To assess the truthfulness of this common concept that first-born twins are usually heavier than their second-born siblings at birth. Methods: In a series of 104 sets of live-born twins, the birth weights of first-born twins were compared with those of their second-born siblings, after controlling for gender. Their intra-pair birthweight differences were determined and twin pairs whose birthweight difference was 15% or more were designated as discordant. Results: Twin I was heavier than Twin II in 61.5% of cases while Twin II was heavier than Twin I in 28.9% of cases. Twins I and II had equal birthweights in 9.6% of cases. Comparing the mean birthweight of the first-born-male twin with that of second-born- male twin, it was 2515+427g (95% Confidence Interval, CI=2402-2628 versus 2432 +435g (95% CI=2321-2543 p>0.05. The mean birthweight of first-born-female twin was 2326+445g (95% CI=2214-2439 while that of the second-born-female twin was 2325+501g (95% CI=2197-2453 p>0.05. When the birthweight difference exceeded 750g, the probability that Twin I will be heavier than Twin II was 83.3% (5 of 6. Conclusion: Although the first-born twin was more often heavier than their second-born siblings, either could weigh more or less at birth. The larger the birthweight difference between growth-discordant twin pair, the greater the probability that the heavier twin would be delivered first

  9. Growth curves for twins in Slovenia.

    Science.gov (United States)

    Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša

    2017-02-01

    Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.

  10. Cerebral metabolism, anatomy, and cognition in monozygotic twins discordant for dementia of the Alzheimer type.

    Science.gov (United States)

    Luxenberg, J S; May, C; Haxby, J V; Grady, C; Moore, A; Berg, G; White, B J; Robinette, D; Rapoport, S I

    1987-03-01

    One pair of monozygotic twins discordant for dementia of the Alzheimer type (DAT) was studied using neuropsychological testing, quantitative x-ray computed tomography (QCT) and magnetic resonance imaging (MRI) of the brain. Cerebral glucose metabolism was measured using positron emission tomography (PET) and 2-[18-F]fluoro-2-deoxy-D-glucose (FDG). The affected twin had a seven year history of progressive cognitive impairment and was severely demented. Neuropsychological testing of the affected twin demonstrated marked deficits in all areas of cognitive function. The asymptomatic twin showed some impairment on tests of perceptual organisation and delayed recall. The affected twin had loss of gray matter and ventricular enlargement on QCT and MRI compared with healthy controls (p less than 0.05). He also had frontal and parietal lobe hypometabolism and increased asymmetry of metabolism on PET compared to both his twin and healthy age-matched controls (p less than 0.05). PET, QCT, and MRI distinguished changes in the twin with DAT compared with his brother and healthy controls. Although the subtle neuropsychological abnormalities of the asymptomatic twin may be signs of early DAT, they were not accompanied by any changes in regional cerebral metabolism or brain structure.

  11. Differences in Religiousness in Opposite-Sex and Same-Sex Twins in a Secular Society.

    Science.gov (United States)

    Ahrenfeldt, Linda J; Lindahl-Jacobsen, Rune; Möller, Sören; Christensen, Kaare; Hvidtjørn, Dorte; Hvidt, Niels Christian

    2016-02-01

    Sex differences in religion are well known, with females generally being more religious than males, and shared environmental factors have been suggested to have a large influence on religiousness. Twins from opposite-sex (OS) and same-sex (SS) pairs may differ because of a dissimilar psycho-social rearing environment and/or because of different exposures to hormones in utero. We hypothesized that OS females may display more masculine patterns of religiousness and, vice versa, that OS males may display more feminine patterns. We used a web-based survey conducted in Denmark, which is a secular society. The survey included 2,997 twins aged 20-40 years, identified through the population-based Danish Twin Registry. We applied la Cour and Hvidt's adaptation of Fishman's three conceptual dimensions of meaning: Cognition, Practice, and Importance, and we used Pargament's measure of religious coping (RCOPE) for the assessment of positive and negative religious coping patterns. Differences between OS and SS twins were investigated using logistic regression for each sex. The analyses were adjusted for dependence within twin pairs. No significant differences in religiousness and religious coping were found for OS and SS twins except that more OS than SS females were members of the Danish National Evangelical Lutheran Church and fewer OS than SS females were Catholic, Muslim, or belonged to other religious denominations. Moreover, OS males at age 12 had higher rates of church attendance than did SS males. This study did not provide evidence for masculinization of female twins with male co-twins with regard to religiousness. Nor did it show any significant differences between OS and SS males except from higher rates of church attendance in childhood among males with female co-twins.

  12. The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design.

    Science.gov (United States)

    Iacono, William G; Heath, Andrew C; Hewitt, John K; Neale, Michael C; Banich, Marie T; Luciana, Monica M; Madden, Pamela A; Barch, Deanna M; Bjork, James M

    2018-08-01

    The ABCD twin study will elucidate the genetic and environmental contributions to a wide range of mental and physical health outcomes in children, including substance use, brain and behavioral development, and their interrelationship. Comparisons within and between monozygotic and dizygotic twin pairs, further powered by multiple assessments, provide information about genetic and environmental contributions to developmental associations, and enable stronger tests of causal hypotheses, than do comparisons involving unrelated children. Thus a sub-study of 800 pairs of same-sex twins was embedded within the overall Adolescent Brain and Cognitive Development (ABCD) design. The ABCD Twin Hub comprises four leading centers for twin research in Minnesota, Colorado, Virginia, and Missouri. Each site is enrolling 200 twin pairs, as well as singletons. The twins are recruited from registries of all twin births in each State during 2006-2008. Singletons at each site are recruited following the same school-based procedures as the rest of the ABCD study. This paper describes the background and rationale for the ABCD twin study, the ascertainment of twin pairs and implementation strategy at each site, and the details of the proposed analytic strategies to quantify genetic and environmental influences and test hypotheses critical to the aims of the ABCD study. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Cervical column morphology and craniofacial profiles in monozygotic twins.

    Science.gov (United States)

    Sonnesen, Liselotte; Pallisgaard, Carsten; Kjaer, Inger

    2008-02-01

    Previous studies have described the relationships between cervical column morphology and craniofacial morphology. The aims of the present study were to describe cervical column morphology in 38 pairs of adult monozygotic (MZ) twins, and compare craniofacial morphology in twins with fusions with craniofacial morphology in twins without fusion. Visual assessment of cervical column morphology and cephalometric measurements of craniofacial morphology were performed on profile radiographs. In the cervical column, fusion between corpora of the second and third vertebrae was registered as fusion. In the twin group, 8 twin pairs had fusion of the cervical column in both individuals within the pair (sub-group A), 25 pairs had no fusions (subgroup B), and in 5 pairs, cervical column morphology was different within the pair (subgroup C), as one twin had fusion and the other did not. Comparison of craniofacial profiles showed a tendency to increased jaw retrognathia, larger cranial base angle, and larger mandibular inclination in subgroup A than in subgroup B. The same tendency was observed within subgroup C between the individual twins with fusion compared with those without fusion. These results confirm that cervical fusions and craniofacial morphology may be interrelated in twins when analysed on profile radiographs. The study also documents that differences in cervical column morphology can occur in individuals within a pair of MZ twins. It illustrates that differences in craniofacial morphology between individuals within a pair of MZ twins can be associated with cervical fusion.

  14. Genetic and Environmental Parent-Child Transmission of Value Orientations: An Extended Twin Family Study

    Science.gov (United States)

    Kandler, Christian; Gottschling, Juliana; Spinath, Frank M.

    2016-01-01

    Despite cross-cultural universality of core human values, individuals differ substantially in value priorities, whereas family members show similar priorities to some degree. The latter has often been attributed to intrafamilial socialization. The analysis of self-ratings on eight core values from 399 twin pairs (ages 7-11) and their biological…

  15. Low Cognitive Functioning in Nondemented 80+-Year-Old Twins Is Not Heritable.

    Science.gov (United States)

    Petrill, Stephen A.; Johansson, Boo; Pedersen, Nancy L.; Berg, Stig; Plomin, Robert; Ahern, Frank; McClearn, Gerald E.

    2001-01-01

    Studied the genetic influence of low cognitive functioning in 200 pairs of twins aged at least 80 years and identified as not demented. Results suggest that the heritability of low cognitive functioning in this group was nonsignificant, but above-average cognitive functioning shows substantial group heritability. (SLD)

  16. Características de superdotação em um par de gêmeos monozigóticos Characteristics of giftedness in a pair of monozygotic twins

    Directory of Open Access Journals (Sweden)

    Carolina Sertã Passos

    2011-12-01

    Full Text Available Com objetivo de comparar características de superdotação em um par de gêmeos monozigóticos, mais especificamente criatividade, motivação e capacidade superior, foram utilizados dados provenientes de um programa que identifica estudantes talentosos com o Modelo das Portas Giratórias. Os gêmeos responderam, também, ao Teste Torrance de Pensamento Criativo, à Escala de Avaliação da Motivação para Aprender de Alunos do Ensino Fundamental e à Bateria de Provas de Raciocínio. Eles possuem superdotação acadêmica e artística, sendo que um deles possui, também, altas habilidades para liderança e comunicação. Verificou-se que eles apresentaram elevada criatividade, principalmente verbal. O envolvimento com a tarefa, que neste estudo foi reduzido à motivação para aprender, não está presente em níveis superiores nos gêmeos. Mais semelhanças que diferenças entre os irmãos, talvez por eles compartilharem genes e ambientes, foram identificadas.Data from program that identifies talent through the Revolving Door Identification Model was used to compare characteristics of giftedness of a pair of monozygotic twins, specifically focusing on creativity, motivation and high ability. The twins also answered the Torrance Test of Creative Thinking, the Scale of Motivation to Learn in Elementary School Students and the Battery of Reasoning Tests. They have academic and artistic giftedness; one of them also has high leadership and communication skills. It was found that they showed great creativity, mainly verbal. Task commitment, which in this study was limited to motivation to learn, is not present at higher levels for the twins. More similarities than differences between the two brothers were identified, possibly because they share genes and environments.

  17. Initiation and strain compatibility of connected extension twins in AZ31 magnesium alloy at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiao, E-mail: liuxiao0105@163.com [Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan, Hunan 411201 (China); State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan 410082 (China); Zhu, Biwu [Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan, Hunan 411201 (China); Huang, Guangjie [College of Materials Science and Engineering, Chongqing University, Chongqing, Chongqing 400045 (China); Li, Luoxing, E-mail: luoxing_li@yahoo.com [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan 410082 (China); Xie, Chao [Faculty of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211 (China); Tang, Changping [Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan, Hunan 411201 (China)

    2016-12-15

    Uniaxial compression tests were carried out at 350 °C and a strain rate of 0.3 s{sup −1} on as-extruded AZ31 magnesium alloy samples. At a true strain of − 0.1, extension twin pairs in a grain and twin chains across adjacent grains were detected. The orientation of selected twins and their host grains were determined by electron backscattered diffraction (EBSD) techniques. The Schmid factors (SFs), accommodation strains and geometric compatibility factors (m{sup ′}) were calculated. Analysis of the data indicated that the formation of twin pair and twin chain was related to the SF and m{sup ′}. Regarding to twin chain across adjacent grains, accommodation strain was also involved. The selection of twin variants in twin chain was generally determined by m{sup ′}. When the twins required the operation of pyramidal slip or twinning in adjacent grain, the corresponding connected twins with a relative high m{sup ′} were selected in this adjacent grain. - Highlights: •The formation of paired twins is studied during high temperature deformation. •The initiation of twinning in twin pair and twin chain obeys the Schmid law. •The twin variants' selection in twin chain is related to the geometric compatibility factor. •The accommodation strain plays an important role on the formation of twin chain.

  18. A twin study of the trough plasma steady-state concentration of metformin

    DEFF Research Database (Denmark)

    Stage, Tore B; Damkier, Per; Pedersen, Rasmus S

    2015-01-01

    OBJECTIVE: The aim of this study was to determine the intrapair similarity in trough steady-state plasma concentrations of metformin in monozygotic and dizygotic twin pairs. METHODS: We included 16 twin pairs (eight monozygotic and eight dizygotic twin pairs) for this study after contacting 524 t...

  19. Effects of exercise training and a hypocaloric diet on female monozygotic twins in free-living conditions.

    Science.gov (United States)

    Koenigstorfer, Joerg; Schmidt, Walter F J

    2011-10-24

    This paper aims to examine the similarities in effects of exercise training and a hypocaloric diet within overweight female monozygotic twin pairs and to assess differences in twin partners' responses depending on the timing of exercise bouts and main meals. Six previously untrained twin pairs (aged 20-37 years, body fat 35.8±6.3%) performed an identical exercise program (12 bouts endurance and 8 bouts resistance training) and took part in a nutrition counseling program for a period of 28 days. They pursued one identical goal: to lose body weight and fat. Each twin partner was randomly assigned to one of the two intervention groups: "exercise after dinner" (A) and "exercise before dinner" (B). Subjects followed a hypocaloric diet, supervised by a nutritionist, in free-living conditions. Reductions in body weight, waist and hip circumference, glucose tolerance, mean daily %fat intake, changes in morning resting energy rate and resting metabolic rate showed great variation between twin pairs, but only small variation within twin pairs. Thus, the genetic influence on the changes in most of the examined anthropometric and physiological variables was high. There was no influence of the specific timing on the dependent variables. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Age-dependent nongenetic influences of birth weight and adult body fat on insulin sensitivity in twins

    DEFF Research Database (Denmark)

    Monrad, Rikke Nygaard; Grunnet, Louise Groth; Rasmussen, Eva Lind

    2009-01-01

    We hypothesized a nongenetic influence of birth weight (BW) and twin and zygosity status on dual-energy x-ray absorptiometry determined adult total and regional body composition and a quantitative equal, although independent, importance of adult body composition and BW for insulin sensitivity....

  1. Placental pathology, birthweight discordance, and growth restriction in twin pregnancy: results of the ESPRiT Study.

    Science.gov (United States)

    Kent, Etaoin M; Breathnach, Fionnuala M; Gillan, John E; McAuliffe, Fionnuala M; Geary, Michael P; Daly, Sean; Higgins, John R; Hunter, Alyson; Morrison, John J; Burke, Gerard; Higgins, Shane; Carroll, Stephen; Dicker, Patrick; Manning, Fiona; Tully, Elizabeth; Malone, Fergal D

    2012-09-01

    We sought to evaluate the association between placental histological abnormalities and birthweight discordance and growth restriction in twin pregnancies. We performed a multicenter, prospective study of twin pregnancies. Placentas were examined for evidence of infarction, retroplacental hemorrhage, chorangioma, subchorial fibrin, or abnormal villus maturation. Association of placental lesions with chorionicity, birthweight discordance, and growth restriction were assessed. In all, 668 twin pairs were studied, 21.1% monochorionic and 78.9% dichorionic. Histological abnormalities were more frequent in placentas of smaller twins of birthweight discordant pairs (P = .02) and in placentas of small for gestational age infants (P = .0001) when compared to controls. The association of placental abnormalities with both birthweight discordance and small for gestational age was significant for dichorionic twins (P = .01 and .0001, respectively). No such association was seen in monochorionic twins. In a large, prospective, multicenter study, we observed a strong relationship between abnormalities of placental histology and birthweight discordance and growth restriction in dichorionic, but not monochorionic, twin pregnancies. Copyright © 2012 Mosby, Inc. All rights reserved.

  2. Is an Early Age at Illness Onset in Schizophrenia Associated With Increased Genetic Susceptibility?

    DEFF Research Database (Denmark)

    Hilker, Rikke; Helenius, Dorte; Fagerlund, Birgitte

    2017-01-01

    with schizophrenia spectrum) and a subsample of N = 448 (affected with schizophrenia). Survival analysis was applied to investigate the effect of age at illness onset. Findings We found that early age at illness onset compared to later onset in the first diagnosed twin can be considered a major risk factor......Background Early age at illness onset has been viewed as an important liability marker for schizophrenia, which may be associated with an increased genetic vulnerability. A twin approach can be valuable, because it allows for the investigation of specific illness markers in individuals...... with a shared genetic background. Methods We linked nationwide registers to identify a cohort of twin pairs born in Denmark from 1951 to 2000 (N = 31,524 pairs), where one or both twins had a diagnosis in the schizophrenia spectrum. We defined two groups consisting of; N = 788 twin pairs (affected...

  3. Gestation period and twinning in chimpanzees.

    Science.gov (United States)

    PEACOCK, L J; ROGERS, C M

    1959-04-10

    The length of the gestation period in 118 births in a colony of chimpanzees was found to be 226.8 days, with a standard deviation of 13.3 and a range of 196 to 260 days. Six pairs of twins were born in 120 parturitions; thus the apparent twinning rate is higher than that in man.

  4. Fetal behavior in normal dichorionic twin pregnancy

    NARCIS (Netherlands)

    Mulder, E. J. H.; Derks, J. B.; de Laat, M. W. M.; Visser, G. H. A.

    2012-01-01

    Objectives: A prospective study was performed to compare fetal behavioral development in healthy dichorionic twins and singletons, and identify twin intra-pair associations (synchrony) of fetal movements and rest-activity cycles using different criteria to define synchrony. Subjects and methods:

  5. Higher Rates of DZ Twinning in a Twenty-First Century Birth Cohort.

    Science.gov (United States)

    Rhea, Sally Ann; Corley, Robin P; Heath, Andrew C; Iacono, William G; Neale, Michael C; Hewitt, John K

    2017-09-01

    The Colorado Twin Registry is a population based registry initiated in 1984 with the involvement of the Colorado Department of Health, Division of Vital Statistics. Recruitment includes birth cohorts several years prior to 1984 and all subsequent years. As part of a recent evaluation of Colorado birth records for the years 2006 through 2008 we became aware of a shifting trend in the proportion of MZ and DZ twins in the Colorado population. Historically (Bulmer 1970 The biology of twinning in man, Clarendon, Oxford) we have expected a 1/3, 1/3, 1/3 ratio of MZ, same-sex DZ and opposite sex DZ twins in Caucasian populations. An excess of MZ pairs in most studies was assumed to be due to selection bias. Somewhat more recently, Hur et al.(1995 Behav Genet 25, 337-340) provided evidence that the DZ twinning rate was falling and that therefore selection bias was not the reason for higher MZ enrollment in most twin studies. They suggested that twin researchers might consider strategies to over-enroll DZ pairs to maximize statistical power. In contrast, we now find that of the 3217 twin births in Colorado from 2006 to 2008 with identified sex information the MZ rate is estimated at only 22%, and we have corroborating reports from other states of similar estimates. These were calculated applying Weinberg's rule which assumes an equal birth rate for same sex and opposite sex DZ pairs so that the proportion of MZ in a sample is the proportion of same sex (MM + FF) minus the proportion of opposite-sex (MF, FM). We explore factors, such as an increase in the proportion of non-Caucasian parents and an increase in average maternal age, which may contribute to this shift.

  6. Heritability of myopia and ocular biometrics in Koreans: the healthy twin study.

    Science.gov (United States)

    Kim, Myung Hun; Zhao, Di; Kim, Woori; Lim, Dong-Hui; Song, Yun-Mi; Guallar, Eliseo; Cho, Juhee; Sung, Joohon; Chung, Eui-Sang; Chung, Tae-Young

    2013-05-01

    To estimate the heritabilities of myopia and ocular biometrics among different family types among a Korean population. We studied 1508 adults in the Healthy Twin Study. Spherical equivalent, axial length, anterior chamber depth, and corneal astigmatism were measured by refraction, corneal topography, and A-scan ultrasonography. To see the degree of resemblance among different types of family relationships, intraclass correlation coefficients (ICC) were calculated. Variance-component methods were applied to estimate the genetic contributions to eye phenotypes as heritability based on the maximum likelihood estimation. Narrow sense heritability was calculated as the proportion of the total phenotypic variance explained by additive genetic effects, and linear and nonlinear effects of age, sex, and interactions between age and sex were adjusted. A total of 240 monozygotic twin pairs, 45 dizygotic twin pairs, and 938 singleton adult family members who were first-degree relatives of twins in 345 families were included in the study. ICCs for spherical equivalent from monozygotic twins, pooled first-degree pairs, and spouse pairs were 0.83, 0.34, and 0.20, respectively. The ICCs of other ocular biometrics were also significantly higher in monozygotic twins compared with other relative pairs, with greater consistency and conformity. The estimated narrow sense heritability (95% confidence interval) was 0.78 (0.71-0.84) for spherical equivalent; 0.86 (0.82-0.90) for axial length; 0.83 (0.76-0.91) for anterior chamber depth; and 0.70 (0.63-0.77) for corneal astigmatism. The estimated heritability of spherical equivalent and ocular biometrics in the Korean population suggests the compelling evidence that all traits are highly heritable.

  7. Dialysis for twins

    DEFF Research Database (Denmark)

    Gramkow, Ann-Maria; Aarup, Michael; Andersen, L. L. T.

    2014-01-01

    A 32-year-old woman with known stage-4 chronic kidney disease due to lupus nephritis presented with twin pregnancy after in vitro fertilization at a gestational age of 24 weeks + 3 days because of imminent preterm labour. Repeated ultrasound evaluations confirmed intrauterine growth restriction...

  8. Measurement non-invariance of DSM-IV narcissistic personality disorder criteria across age and sex in a population-based sample of Norwegian twins.

    Science.gov (United States)

    Kubarych, Thomas S; Aggen, Steven H; Kendler, Kenneth S; Torgersen, Sven; Reichborn-Kjennerud, Ted; Neale, Michael C

    2010-09-01

    We investigated measurement non-invariance of DSM-IV narcissistic personality disorder (NPD) criteria across age and sex in a population-based cohort sample of 2794 Norwegian twins. Age had a statistically significant effect on the factor mean for NPD. Sex had a statistically significant effect on the factor mean and variance. Controlling for these factor level effects, item-level analysis indicated that the criteria were functioning differently across age and sex. After correcting for measurement differences at the item level, the latent factor mean effect for age was no longer statistically significant. The mean difference for sex remained statistically significant after correcting for item threshold effects. The results indicate that DSM-IV NPD criteria perform differently in males and females and across age. Differences in diagnostic rates across groups may not be valid without correcting for measurement non-invariance.

  9. Fetal growth disorders in twin gestations.

    LENUS (Irish Health Repository)

    Breathnach, Fionnuala M

    2012-06-01

    Twin growth is frequently mismatched. This review serves to explore the pathophysiologic mechanisms that underlie growth aberrations in twin gestations, the prenatal recognition of abnormal twin growth, and the critical importance of stratifying management of abnormal twin growth by chorionicity. Although poor in utero growth of both twins may reflect maternal factors resulting in global uteroplacental dysfunction, discordant twin growth may be attributed to differences in genetic potential between co-twins, placental dysfunction confined to one placenta only, or one placental territory within a shared placenta. In addition, twin-twin transfusion syndrome represents a distinct entity of which discordant growth is a common feature. Discordant growth is recognized as an independent risk factor for adverse perinatal outcome. Intertwin birth weight disparity of 18% or more should be considered to represent a discordance threshold, which serves as an independent risk factor for adverse perinatal outcome. At this cutoff, perinatal morbidity is found to increase both for the larger and the smaller twin within a discordant pair. There remains uncertainty surrounding the sonographic parameters that are most predictive of discordance. Although heightening of fetal surveillance in the face of discordant twin growth follows the principles applied to singleton gestations complicated by fetal growth restriction, the timing of intervention is largely influenced by chorionicity.

  10. Genetic and Environmental Regulation on Longitudinal Change of Metabolic Phenotypes in Danish and Chinese Adult Twins

    DEFF Research Database (Denmark)

    Li, Shuxia; Kyvik, Kirsten Ohm; Pang, Zengchang

    2016-01-01

    OBJECTIVE: The rate of change in metabolic phenotypes can be highly indicative of metabolic disorders and disorder-related modifications. We analyzed data from longitudinal twin studies on multiple metabolic phenotypes in Danish and Chinese twins representing two populations of distinct ethnic...... pairs traced for about 7 years with a mean baseline age of 39.5 years (range: 23-64). The classical twin models were fitted to the longitudinal change in each phenotype (Δphenotype) to estimate the genetic and environmental contributions to the variation in Δphenotype. RESULTS: Moderate to high...... contributions by the unique environment were estimated for all phenotypes in both Danish (from 0.51 for low density lipoprotein cholesterol up to 0.72 for triglycerides) and Chinese (from 0.41 for triglycerides up to 0.73 for diastolic blood pressure) twins; low to moderate genetic components were estimated...

  11. Atopic diseases in twins born after assisted reproduction.

    Science.gov (United States)

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten O; Skytthe, Axel; Backer, Vibeke

    2012-03-01

    We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0.773 respectively) compared with children born after spontaneous conception. Assisted reproduction did not modify the heritability of atopic diseases. This study does not support an association between assisted reproduction and development of atopic diseases. This result must be confirmed in subsequent studies, preferably of singleton populations. © 2011 Blackwell Publishing Ltd.

  12. Twinning rate in a sample from a Brazilian hospital with a high standard of reproductive care

    Directory of Open Access Journals (Sweden)

    Gloria Maria Duccini Dal Colletto

    Full Text Available CONTEXT: Epidemiological studies on twin births have been motivated mostly by the positive correlation between twinning rate and human fertility, prematurity, low birth weight, increased risk of infant death and long term risk for morbidity. OBJECTIVE: This paper intends to estimate the incidence of multiple births in a private hospital in Brazil with a high standard of reproductive care, and to evaluate the effects of maternal age, gestation order and assisted fertilization on twinning rate. DESIGN: Retrospective analysis. SETTING: First-class tertiary private hospital, São Paulo, Brazil. PARTICIPANTS: The multiple birth rate was investigated among 7,997 deliveries from 1995 to 1998, including 7,786 singletons, 193 twins, 17 triplets and one quadruplet. RESULTS: The rates per 1,000 dizygotic and monozygotic pairs and for triplets were estimated as 19.51, 4.50 and 2.13, respectively. The dizygotic and triplet rates were the highest observed in Brazil up to the present day. The twinning rate among primigravidae older than 30 years was very high (45.02 per 1,000 and was due to a disproportionately high frequency of dizygotic pairs. The triplet rate was also very high among the mothers of this age group (5.71 per 1,000. These facts are strong indicators that these women were the ones most frequently submitted to assisted reproductive techniques. The mean maternal age of the studied population was about six years higher than that estimated for mothers in the general population of southeastern Brazil. Primigravidae aged under 30 years as well as multigravidae showed similar twinning rates, which were almost 20 per 1,000. Among the deliveries of multigravidae older than 30 years, an unusually high frequency of monozygotic twins was observed (7.04 per 1,000, probably as a consequence of the residual effect of long-term use of oral contraceptives. CONCLUSIONS: The dizygotic twinning rate increased from 13.51 to 28.98 per 1,000 over the four years

  13. Fingerprint recognition with identical twin fingerprints.

    Science.gov (United States)

    Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

    2012-01-01

    Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  14. Fingerprint recognition with identical twin fingerprints.

    Directory of Open Access Journals (Sweden)

    Xunqiang Tao

    Full Text Available Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6 images. Compared to the previous work, our contributions are summarized as follows: (1 Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2 Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3 A larger sample (83 pairs was collected. (4 A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5 A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  15. Twin Delivery: Comparison of Incidence and Foetal Outcome in two ...

    African Journals Online (AJOL)

    Background: The incidence of twin delivery in Nigeria may have changed, in view of the worldwide increase in the rates of twinning attributed to increasing maternal age and use of fertility therapies. Objective: To determine the current incidence of twin delivery in Benin City and document the foetal outcome in twins.

  16. Twin studies advance the understanding of gene-environment interplay in human nutrigenomics.

    Science.gov (United States)

    Pallister, Tess; Spector, Tim D; Menni, Cristina

    2014-12-01

    Investigations into the genetic architecture of diet-disease relationships are particularly relevant today with the global epidemic of obesity and chronic disease. Twin studies have demonstrated that genetic makeup plays a significant role in a multitude of dietary phenotypes such as energy and macronutrient intakes, dietary patterns, and specific food group intakes. Besides estimating heritability of dietary assessment, twins provide a naturally unique, case-control experiment. Due to their shared upbringing, matched genes and sex (in the case of monozygotic (MZ) twin pairs), and age, twins provide many advantages over classic epidemiological approaches. Future genetic epidemiological studies could benefit from the twin approach particularly where defining what is 'normal' is problematic due to the high inter-individual variability underlying metabolism. Here, we discuss the use of twins to generate heritability estimates of food intake phenotypes. We then highlight the value of discordant MZ pairs to further nutrition research through discovery and validation of biomarkers of intake and health status in collaboration with cutting-edge omics technologies.

  17. A synthetic medical and sociological study of A-bomb exposed twin, 7

    International Nuclear Information System (INIS)

    Watanabe, Shoji; Satow, Yukio; Kyo, Taiichi

    1984-01-01

    The status of A-bomb exposure and family or relative relationship were investigated in seven twin pairs exposed to A-bomb (14 survivors). The survivors ranged in age between 4 and 24 years when they were exposed to A-bomb. Twins' relationship was comparatively strong. Both of the twins who were exposed to A-bomb tended to be closely connected with each other because of the fearful experience of A-bomb exposure and the subsequent hard social life. Even though one of the pair was not exposed to A-bomb, he (she) was likely to continue to help the other for a long time to restore from the disaster. (Namekawa, K.)

  18. Long-term relationships between symptoms of Attention Deficit Hyperactivity Disorder and self-esteem in a prospective longitudinal study of twins.

    Science.gov (United States)

    Edbom, Tobias; Lichtenstein, Paul; Granlund, Mats; Larsson, Jan-Olov

    2006-06-01

    To study the long-term relationship between symptoms of Attention Deficit Hyperactivity Disorder and the developing self-esteem in a population-based sample of twins. The cohort is all twin pair families born in Sweden between May 1985 and December 1986 (n = 1.480). Wave 1 took place in 1994 when the twins were 8 years old and wave 2 in 1999 when the children were 13 years old. In wave 1 and 2 the parents completed questionnaires regarding ADHD-symptoms about their children. In wave 2 the twins completed a questionnaire about self-esteem and Youth Self Report (YSR). ADHD-symptoms and self-esteem were analyzed in the total study group. There was a long-term relationship between high scores of parental-reported ADHD-symptoms at 8 and 13 years of age and low scores in measures of self-reported self-esteem at 13 years of age. In the cotwin control method controlling for YSR internalizing problem, paired comparisons within the twin pairs revealed that a high score of ADHD-symptoms at age 8 was related to significantly lower scores at age 13 in the self-esteem. The long-term relationships between ADHD-symptoms and a low self-esteem in a population-based sample were confirmed by the co-twin analyses.

  19. Twins with omphalocele in Denmark (1970-1989)

    DEFF Research Database (Denmark)

    Bugge, Merete

    2010-01-01

    Seven pairs of twins, two monozygotic (MZ), two dizygotic (DZ), and three like-sex pairs of unknown zygosity are described. The twin pairs were all discordant for omphalocele except for one pair of conjoined twins. The 8 infants with omphalocele represent 3.1% of the 253 infants with omphalocele......, ascertained in an almost complete nationwide data set of live- and stillborn infants with abdominal wall defects in two decades in Denmark (1970-1989). The occurrence of twins with omphalocele was not significantly different from the occurrence of twins in the Danish population in the same period. To our...... knowledge this is the first report of the occurrence of twins with omphalocele in a systematic nationwide epidemiological study....

  20. A longitudinal investigation of the associations among parenting, deviant peer affiliation, and externalizing behaviors: a monozygotic twin differences design.

    Science.gov (United States)

    Hou, Jinqin; Chen, Zhiyan; Natsuaki, Misaki N; Li, Xinying; Yang, Xiaodong; Zhang, Jie; Zhang, Jianxin

    2013-06-01

    Non-shared parenting and deviant peer affiliation are linked to differences in externalizing behaviors between twins. However, few studies have examined these two non-shared environments simultaneously. The present study examined the transactional roles of differential parenting (i.e., warmth and hostility) and deviant peer affiliation on monozygotic (MZ) twin differences in externalizing behaviors using a two-wave longitudinal study of twins and their parents. The sample consisted of 520 pairs of MZ twins (46.5% males, 53.5% females), with a mean age of 13.86 years (SD = 2.10) at the T1 assessment, residing in Beijing, China. The association between non-shared hostility in parenting and adolescent externalizing behaviors was mainly explained by a child-driven effect whereby the twin with a higher level of externalizing behaviors than his or her co-twin was more likely to receive more hostility from the parents. Similarly, the relationship between deviant peer affiliation and adolescent externalizing behaviors supported the selection effect whereby the twin with a higher level of externalizing behaviors than his or her co-twin was more likely to affiliate with deviant peers. The theoretical and practical implications of these findings are discussed.

  1. The identical-twin transfusion syndrome: a source of error in estimating IQ resemblance and heritability.

    Science.gov (United States)

    Munsinger, H

    1977-01-01

    Published studies show that among identical twins, lower birthweight is associated with lower adult intelligence. However, no such relation between birthweight and adult IQ exists among fraternal twins. A likely explanation for the association between birthweight and intelligence among identical twins is the identical twin transfusion syndrome which occurs only between some monochorionic identical twin pairs. The IQ scores from separated identical twins were reanalysed to explore the consequences of identical twin transfusion syndrome for IQ resemblance and heritability. Among 129 published cases of identical twin pairs reared apart, 76 pairs contained some birthweight information. The 76 pairs were separated into three classes: 23 pairs in which there was clear evidence of a substantial birthweight differences (indicating the probable existence of the identical twin transfusion syndrome), 27 pairs in which the information on birthweight was ambiguous (?), and 26 pairs in which there was clear evidence that the twins were similar in birthweight. The reanalyses showed: (1) birthweight differences are positively associated with IQ differences in the total sample of separated identical twins; (2) within the group of 23 twin pairs who showed large birthweight differences, there was a positive relation between birthweight differences and IQ differences; (3) when heritability of IQ is estimated for those twins who do not suffer large birthweight differences, the resemblance (and thus, h2/b) of the separated identical twins' IG is 0-95. Given that the average reliability of the individual IQ test is around 0-95, these data suggest that genetic factors and errors of measurement cause the individual differences in IQ among human beings. Because of the identical twin transfusion syndrome, previous studies of MZ twins have underestimated the effect of genetic factors on IQ. An analysis of the IQs for heavier and lighter birthweight twins suggests that the main effect of the

  2. [Association between obesity and DNA methylation among the 7-16 year-old twins].

    Science.gov (United States)

    Li, C X; Gao, Y; Gao, W J; Yu, C Q; Lyu, J; Lyu, R R; Duan, J L; Sun, Y; Guo, X H; Wang, S F; Zhou, B; Wang, G; Cao, W H; Li, L M

    2018-04-10

    Objective: On whole-genome scale, we tried to explore the correlation between obesity-related traits and DNA methylation sites, based on discordant monozygotic twin pairs. Methods: A total of 90 pairs of 6-17 year-old twins were recruited in Chaoyang district, Yanqing district and Fangshan district in Beijing in 2016. Information on twins was gathered through a self-designed questionnaire and results: from physical examination, including height, weight and waist circumference of the subjects under study. DNA methylation detection was chosen on the Illumina Human Methylation EPIC BeadChip. R 3.3.1 language was used to read the DNA methylation signal under quality control on samples and probes. Ebayes function of empirical Bayes paired moderated t -test was used to identify the differential methylated CpG sites (DMCs). VarFit function of empirical Bayes paired moderated Levene test was used to identify the differentially variables CpG sits (DVCs) in obese and normal groups. Results According to the obesity discordance criteria, we collected 23 pairs of twins (age range 7 to 16 years), including 12 male pairs. A total of 817 471 qualified CpG loci were included in the genome-wide correlation analysis. According to the significance level of FDR set as obesity traits. After multiple testing corrections, no positive sites were found to have associated with obesity. However, results from the correlation analysis demonstrated sites cg05684382 (chr: 12) and cg26188191 (chr: 16) might have played a role in the development of obesity. This study provides a methodologic reference for the studies on discordance twins related problems.

  3. The Impact of Preschool Twins' Physical Difficulties on Parental Perceptions towards Separation, Closeness and Friendship

    Science.gov (United States)

    Markodimitraki, Maria; Linardakis, Michalis; Kypriotaki, Maria; Manolitsis, George

    2016-01-01

    The aims of this study were to: (a) provide descriptive data of twins with physical difficulties among 120 Greek twins of preschool age; and (b) to investigate the impact of twins' health condition on parental perceptions towards twins' separation, closeness and friendship. The administration of School Policy for Twins and Higher Multiples…

  4. Heritability of Age-Related Hearing Loss in Middle-Aged and Elderly Chinese

    DEFF Research Database (Denmark)

    Duan, Haiping; Zhang, Dongfeng; Liang, Yajun

    2018-01-01

    OBJECTIVES: The heritability of age-related hearing loss has been studied mostly in developed countries. The authors aimed to estimate the heritability of better ear hearing level (BEHL), defined as hearing level of the better ear at a given frequency, and pure-tone averages at the middle (0.5, 1.......0, and 2.0 kHz) and high (4.0, 8.0, and 12.5 kHz) frequencies among middle-aged and elderly Chinese twins, and to explore their genetic correlations. DESIGN: This population-based twin study included 226 monozygotic and 132 dizygotic twin-pairs and 1 triplet (age range, 33 to 80 years; mean age, 51.......75 at high frequencies. CONCLUSIONS: This population-based twin study suggests that genetic factors are associated with age-related hearing loss at middle and high frequencies among middle-aged and elderly Chinese....

  5. Aortic distensibility as a surrogate for intertwin pulse pressure differences in monochorionic pregnancies with and without twin-twin transfusion syndrome.

    Science.gov (United States)

    Wohlmuth, C; Osei, F A; Moise, K J; Johnson, A; Papanna, R; Bebbington, M; Gardiner, H M

    2016-08-01

    Twin-twin transfusion syndrome (TTTS) complicates 10-15% of monochorionic diamniotic (MCDA) twin pregnancies. The donor response to hypovolemia allows the transfer of vasoactive mediators to the recipient, causing increased recipient afterload and hypertension. Our objective was to apply a novel speckle-tracking technique to measure the aortic fractional area change (AFAC) during the cardiac cycle in MCDA twins with and without TTTS, and identify intertwin differences in AFAC and parameters of cardiac function. High-frame rate four-chamber views of the fetal heart, including the mid-thoracic aorta, were collected prospectively in MCDA twin pairs referred to our center between June 2014 and April 2015. Using speckle-tracking software, the endovascular border of the aorta was traced manually during systole, with guidance on cardiac cycle timing by anatomical M-mode. AFAC, defined as the difference between maximum and minimum area divided by minimum area, expressed as a percentage, was calculated offline and averaged over three cardiac cycles. Tissue Doppler and displacement were used to measure long-axis cardiac function. Intra- and interclass correlation coefficients were used to test observer variability. Fifty-one MCDA twin pregnancies were included, comprising uncomplicated MCDA (n = 14), TTTS Stages 1/2 (n = 21) and TTTS Stages 3/4 (n = 16). Median gestational age was 20.4 (range, 16.2-27.5) weeks. Mean ± SD heart rate was 142.6 ± 7.2 bpm with no significant intertwin pair differences. AFAC was significantly higher in recipients than in donors of TTTS pairs (Stages 1/2: 72.3 ± 29.9% vs 43.7 ± 19.3%, P pregnancies with TTTS. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

  6. Genetic and environmental influences on motor function: a magnetoencephalographic study of twins

    Directory of Open Access Journals (Sweden)

    Toshihiko eAraki

    2014-06-01

    Full Text Available To investigate the effect of genetic and environmental influences on cerebral motor function, we determined similarities of movement-related cortical fields (MRCFs in middle-aged and elderly monozygotic (MZ twins. MRCFs were measured using a 160-channel MEG system when MZ twins were instructed to repeat lifting of the right index finger. We compared latency, amplitude, dipole location, and dipole intensity of movement-evoked field 1 (MEF1 between 16 MZ twins and 16 pairs of genetically unrelated pairs. Differences in latency and dipole location between MZ twins were significantly less than those between unrelated age-matched pairs. However, amplitude and dipole intensity were not significantly different. These results suggest that the latency and dipole location of MEF1 are determined early in life by genetic and early common environmental factors, whereas amplitude and dipole intensity are influenced by long-term environmental factors. Improved understanding of genetic and environmental factors that influence cerebral motor function may contribute to evaluation and improvement for individual motor function.

  7. Twin study of heritability of eating bread in Danish and Finnish men and women

    DEFF Research Database (Denmark)

    Hasselbalch, Ann Louise; Silventoinen, Karri; Keskitalo, Kaisu

    2010-01-01

    Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. The study...... cohorts included 575 Danish (age range 18-67 years) and 2009 Finnish (age range 22-27 years) adult twin pairs. Self-reported frequency of eating bread was obtained by food frequency questionnaires. Univariate models based on linear structural equations for twin data were used to estimate the relative...... magnitude of the additive genetic, shared environmental and individual environmental effects on bread eating frequency and choice of bread. The analysis of bread intake frequency demonstrated moderate heritability ranging from 37-40% in the Finnish cohort and 23-26% in the Danish cohort. The genetic...

  8. Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age.

    Science.gov (United States)

    Wright, David J; Brouwer, Lyanne; Mannarelli, Maria-Elena; Burke, Terry; Komdeur, Jan; Richardson, David S

    2016-01-01

    The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler ( Acrocephalus sechellensis ), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male-male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues.

  9. Estimating twin concordance for bivariate competing risks twin data

    DEFF Research Database (Denmark)

    Scheike, Thomas; Holst, Klaus K.; Hjelmborg, Jacob B.

    2014-01-01

    For twin time-to-event data, we consider different concordance probabilities, such as the casewise concordance that are routinely computed as a measure of the lifetime dependence/correlation for specific diseases. The concordance probability here is the probability that both twins have experience...... events with the competing risk death. We thus aim to quantify the degree of dependence through the casewise concordance function and show a significant genetic component...... the event of interest. Under the assumption that both twins are censored at the same time, we show how to estimate this probability in the presence of right censoring, and as a consequence, we can then estimate the casewise twin concordance. In addition, we can model the magnitude of within pair dependence...... over time, and covariates may be further influential on the marginal risk and dependence structure. We establish the estimators large sample properties and suggest various tests, for example, for inferring familial influence. The method is demonstrated and motivated by specific twin data on cancer...

  10. Attractiveness Differences Between Twins Predicts Evaluations of Self and Co-Twin

    Science.gov (United States)

    Principe, Connor P.; Rosen, Lisa H.; Taylor-Partridge, Teresa; Langlois, Judith H.

    2012-01-01

    One of the most consistent findings in psychology shows that people prefer and make positive attributions about attractive compared with unattractive people. The goal of the current study was to determine the power of attractiveness effects by testing whether these social judgments are made where attractiveness differences are smallest: between twins. Differences in facial attractiveness predicted twins’ evaluations of self and their co-twin (n = 158; 54 male). In twin pairs, the more attractive twin judged their less attractive sibling as less physically attractive, athletic, socially competent, and emotionally stable. The less attractive twin did the reverse. Given that even negligible differences in facial attractiveness predicted self and co-twin attitudes, these results provide the strongest test yet of appearance-based stereotypes. PMID:23467329

  11. Association of Educational Level and Marital Status With Obesity: A Study of Chinese Twins.

    Science.gov (United States)

    Liao, Chunxiao; Gao, Wenjing; Cao, Weihua; Lv, Jun; Yu, Canqing; Wang, Shengfeng; Li, Chunxiao; Pang, Zengchang; Cong, Liming; Dong, Zhong; Wu, Fan; Wang, Hua; Wu, Xianping; Jiang, Guohong; Wang, Xiaojie; Wang, Binyou; Li, Liming

    2018-04-01

    The prevalence of overweight and obesity is growing rapidly in many countries. Socioeconomic inequalities might be important for this increase. The aim of this study was to determine associations of body mass index (BMI), overweight and obesity with educational level and marital status in Chinese twins. Participants were adult twins recruited through the Chinese National Twin Registry (CNTR), aged 18 to 79 years, and the sample comprised 10,448 same-sex twin pairs. Current height, weight, educational attainment, and marital status were self-reported. Regression analyses and structural equation models were conducted to evaluate BMI, overweight, and obesity associated with educational level and marital status in both sexes. At an individual level, both educational level and marital status were associated with higher BMI and higher risk of being overweight and obesity in men, while in women the effects of educational level on BMI were in the opposite direction. In within-Monozygotic (MZ) twin-pair analyses, the effects of educational level on BMI disappeared in females. Bivariate structural equation models showed that genetic factors and shared environmental confounded the relationship between education and BMI in females, whereas marital status was associated with BMI on account of significant positive unique environmental correlation apart in both sexes. The present data suggested that marital status and BMI were associated, independent of familiar factors, for both sexes of this study population, while common genetic and shared environmental factors contributed to education-associated disparities in BMI in females.

  12. Analysis of electron pair production in the collision system Ar+KCl at 1.76 AGeV

    International Nuclear Information System (INIS)

    Lang, Simon Martin

    2008-01-01

    The HADES-spectrometer at GSI is used to measure the production of the light vector mesons ρ, ω and φ at SIS energies. Therefore, the medium sized collision system Ar+KCl was measured at 1.76 AGeV kinetic energy of beam particles. In this system the density of particle tracks is much larger as compared to the formerly used collision system C+C, making it necessary to upgrade the data analysis. The previous method of hard-cuts - used for particle identification - was replaced by a newly developed multi-variate analysis based on an artificial neural network. This algorithm has the benefit, that it is more robust against fluctuations in one or more of the used detector observables. This increases the overall efficiency and purity of the analysis procedure. Furthermore, the reconstruction of particle tracks inside the HADES spectrometer is based on a few position information, only. During analysis of raw data, these information are combined to a artificially large manifold of tracks. This leads to the general problem that one has to select the maximum number of true physical tracks out of this set of tracks per event. A new method of track selection is used to filter the data not only to select single tracks, but also to identify electron pairs created during Dalitz-decay of π 0 mesons, which build the bulk of combinatorial background. The result of the analysis is an efficiency corrected invariant mass spectrum of electron pairs, normalized to the mean number of pions per event. The spectrum consists of more than 16,000 pairs with an invariant mass larger than 150 MeV. In total more than 150000 pairs were found. A first comparison with the spectra calculated by using the old analysis approach shows a 30% enhancement in yield of reconstructed electron pairs. A first comparison with a simple thermal model implemented by the Pluto event generator, opens the possibility to compare the measured pair yield of ω and φ mesons via m T -scaling with the yield of η mesons

  13. Bilateral Norrie's disease in identical twins.

    OpenAIRE

    Sukumaran, K

    1991-01-01

    A case of Norrie's disease in an identical twins is reported. No positive family history was obtained. The couple had no other children. The older of the twins died at the age of 9 months of uncertain cause. To the best of my knowledge this is the first case of Norrie's disease reported in Malaysia. And its occurrence in an identical twins is very rare.

  14. Genetic regulation of pre-pubertal development of body mass index: a longitudinal study of Japanese twin boys and girls.

    Science.gov (United States)

    Silventoinen, Karri; Kaprio, Jaakko; Yokoyama, Yoshie

    2011-03-01

    We analyzed the genetic architecture of prepubertal development of relative weight to height in 216 monozygotic and 159 dizygotic complete Japanese twin pairs (52% girls). Ponderal index at birth (kg/m(3)) and body mass index (BMI, kg/m(2)) from 1 to 11 years of age were used. Additive genetic factors explained the major proportion (52-74%) of the variation of BMI from 1 to 11 years of age. Environmental factors common to both co-twins also showed some effect (7-28%), but at most ages this was not statistically significant. Strong genetic tracking was found for BMI from 1 to 11 years of age, but there was also evidence for a persistent effect of common environmental factors. Our results suggest that the genetic architecture of BMI development in the Japanese population is generally similar to that found in previous twin studies in Caucasian populations.

  15. Urticaria in monozygotic and dizygotic twins

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; van der Sluis, Sophie; Kyvik, Kirsten Ohm

    2012-01-01

    Aim. To identify risk factors for urticaria, to determine the relative proportion of the susceptibility to urticaria that is due to genetic factors in an adult clinical twin sample, and to further determine whether the genetic susceptibility to urticaria overlaps with the genetic susceptibility...... to atopic diseases. Methods. A total of 256 complete twin pairs and 63 single twins, who were selected from sibships with self-reported asthma via a questionnaire survey of 21,162 adult twins from the Danish Twin Registry, were clinically interviewed about a history of urticaria and examined for atopic...... diseases. Data were analysed with Cox proportional hazards regression and variance components models. Results. A total of 151 individuals (26%) had a history of urticaria, whereas 24 (4%) had had symptoms within the past year. Female sex, HR = 2.09 (1.46-2.99), P = 0.000; hay fever, HR = 1.92 (1...

  16. Risk Factors Influencing Smoking Behavior: A Turkish Twin Study

    Science.gov (United States)

    Öncel, Sevgi Yurt; Dick, Danielle M.; Maes, Hermine H.; Alıev, Fazil

    2015-01-01

    Aim In this study, we introduce the first twin study in Turkey, focusing on smoking behavior, and laying the foundation to register all twins born in Turkey for research purposes. Using Turkish twins will contribute to our understanding of health problems in the context of cultural differences. Materials and methods We assessed 309 twin pairs (339 males and 279 females) aged between 15 and 45 years living in the Kırıkkale and Ankara regions of Turkey, and administered a health and lifestyle interview that included questions about smoking status and smoking history. We analyzed the data using descriptive statistics, t-tests, chi-square tests, and bivariate and multivariate clustered logistic regression. In addition, we fit bivariate Structural Equation Models (SEM) to determine contributions of latent genetic and environmental factors to smoking outcomes in this sample. Results One hundred seventy-eight participants (28.8%) were identified as smokers, smoking every day for a month or longer, of whom 79.2% were males and 20.8% were females. Mean values for number of cigarettes per day and the Fagerstrom Test of Nicotine Dependence (FTND; Fagerstrom, 1978) score were higher in males than in females, and age of onset was earlier in males. There was a significant positive correlation between the FTND score and number of cigarettes smoked per day, and a significant negative correlation between both variables and age at onset of smoking. Our study showed that gender, presence of a smoking twin in the family, age, alcohol use, marital status, daily sports activities, and feeling moody all played a significant role in smoking behavior among twins. The twin analysis suggested that 79.5% of the liability to FTND was influenced by genetic factors and 20.5% by unique environment, while familial resemblance for smoking initiation was best explained by common environmental factors. Conclusions Marked differences in the prevalence of smoking behavior in men versus women were

  17. Familial resemblance in religiousness in a secular society: a twin study.

    Science.gov (United States)

    Hvidtjørn, Dorte; Petersen, Inge; Hjelmborg, Jacob; Skytthe, Axel; Christensen, Kaare; Hvidt, Niels C

    2013-04-01

    It is well known that human behavior and individual psychological traits are moderately to substantially heritable. Over the past decade, an increasing number of studies have explored the genetic and environmental influence on religiousness. These studies originate predominantly from countries generally considered more religious than the very secular northern European countries. Comparisons of the results are complicated by diverse definitions of religiousness, but several studies indicate that the influence of the family environment is most predominant in early life, whereas genetic influences increase with age. We performed a population-based twin study of religiousness in a secular society using data from a Web-based survey sent to 6,707 Danish twins born 1970-1989, who were identified in the Danish Twin Registry. We applied Fishman's three conceptual dimensions of religiousness: cognition, practice, and importance. In all polygenic models and biometric analyses, we controlled for gender and age. The study sample comprised 2,237 same sex twins, a response rate of 45%. We found high correlations within both monozygotic and dizygotic twin pairs in most items of religiousness, indicating a large influence from shared environmental factors. Personal religiousness such as praying to God, believing in God, and finding strength and comfort in religion were more influenced by genetic factors than were social forms of religiousness such as church attendance. We found a small tendency for increasing genetic influence with increasing age for some religious items, but not for all.

  18. The Effect of Birth Order on Neonatal Morbidity and Mortality in Very Preterm Twins.

    Science.gov (United States)

    Mei-Dan, Elad; Shah, Jyotsna; Lee, Shoo; Shah, Prakesh S; Murphy, Kellie E

    2017-07-01

    Objective  This retrospective cohort study examined the effect of birth order on neonatal morbidity and mortality in very preterm twins. Study Design  Using 2005 to 2012 data from the Canadian Neonatal Network, very preterm twins born between 24 0/7 and 32 6/7 weeks of gestation were included. Odds of morbidity and mortality of second-born cotwins compared with first-born cotwins were examined by matched-pair analysis. Outcomes were neonatal death, severe brain injury (intraventricular hemorrhage grade 3 or 4 or persistent periventricular echogenicity), bronchopulmonary dysplasia, severe retinopathy of prematurity (ROP) (> stage 2), necrotizing enterocolitis (≥ stage 2), and respiratory distress syndrome (RDS). Multivariable analysis was performed adjusting for confounders. Result  There were 6,636 twins (3,318 pairs) included with a mean gestational age (GA) of 28.9 weeks. A higher rate of small for GA occurred in second-born twins (10 vs. 6%). Mortality was significantly lower for second-born twins (4.3 vs. 5.3%; adjusted odds ratio: 0.75; 95% confidence interval [CI]: 0.59-0.95). RDS (66 vs. 60%; adjusted odds ratio: 1.40; 95% CI: 1.29-1.52) and severe retinopathy (9 vs. 7%; adjusted odds ratio: 1.46; 95% CI: 1.07-2.01) were significantly higher in second-born twins. Conclusion  Thus, while second-born twins had reduced odds of mortality, they also had increased odds of RDS and ROP. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  19. Psycholinguistic measures for German verb pairs: Semantic transparency, semantic relatedness, verb family size, and age of reading acquisition.

    Science.gov (United States)

    Smolka, Eva; Eulitz, Carsten

    2018-06-18

    A central issue in visual and spoken word recognition is the lexical representation of complex words-in particular, whether the lexical representation of complex words depends on semantic transparency: Is a complex verb like understand lexically represented as a whole word or via its base stand, given that its meaning is not transparent from the meanings of its parts? To study this issue, a number of stimulus characteristics are of interest that are not yet available in public databases of German. This article provides semantic association ratings, lexical paraphrases, and vector-based similarity measures for German verbs, measuring (a) the semantic transparency between 1,259 complex verbs and their bases, (b) the semantic relatedness between 1,109 verb pairs with 432 different bases, and (c) the vector-based similarity measures of 846 verb pairs. Additionally, we include the verb regularity of all verbs and two counts of verb family size for 184 base verbs, as well as estimates of age of acquisition and age of reading for 200 verbs. Together with lemma and type frequencies from public lexical databases, all measures can be downloaded along with this article. Statistical analyses indicate that verb family size, morphological complexity, frequency, and verb regularity affect the semantic transparency and relatedness ratings as well as the age of acquisition estimates, indicating that these are relevant variables in psycholinguistic experiments. Although lexical paraphrases, vector-based similarity measures, and semantic association ratings may deliver complementary information, the interrater reliability of the semantic association ratings for each verb pair provides valuable information when selecting stimuli for psycholinguistic experiments.

  20. Playing a Musical Instrument as a Protective Factor against Dementia and Cognitive Impairment: A Population-Based Twin Study.

    Science.gov (United States)

    Balbag, M Alison; Pedersen, Nancy L; Gatz, Margaret

    2014-01-01

    Increasing evidence supports that playing a musical instrument may benefit cognitive development and health at young ages. Whether playing an instrument provides protection against dementia has not been established. In a population-based cotwin control study, we examined the association between playing a musical instrument and whether or not the twins developed dementia or cognitive impairment. Participation in playing an instrument was taken from informant-based reports of twins' leisure activities. Dementia diagnoses were based on a complete clinical workup using standard diagnostic criteria. Among 157 twin pairs discordant for dementia and cognitive impairment, 27 pairs were discordant for playing an instrument. Controlling for sex, education, and physical activity, playing a musical instrument was significantly associated with less likelihood of dementia and cognitive impairment (odds ratio [OR] = 0.36 [95% confidence interval 0.13-0.99]). These findings support further consideration of music as a modifiable protective factor against dementia and cognitive impairment.

  1. Magnetic resonance in multiple sclerose twins

    International Nuclear Information System (INIS)

    Polman, C.H.; UitdeHaag, B.M.J.; Koetsier, C.J.; Valk, J.; Lucas, C.J.

    1989-01-01

    Magnetic resonance imaging (MR) examinations were performed in a series of 7 twin sets (4 monozygotic and 3 dizygotic) and one triplet set who were clinically discordant for multiple sclerosis (MS). MRI abnormalities were detected in a number of the unaffected members of the nonzygotic twin pairs. The authors discuss the possible implications of their findings for the present view on the aetiology of MS. (author). 3 refs.; 1 fig.; 1 tab

  2. Screening and Invasive Testing in Twins

    Directory of Open Access Journals (Sweden)

    Giovanni Monni

    2014-07-01

    Full Text Available Prenatal screening and testing for trisomy 21 in twin pregnancies poses a number of challenges: the exact estimate of the a priori risk of trisomy 21, the choice of prenatal screening test and/or invasive techniques to employ for the diagnosis and the impact of the result on the options of treatment in case of discordant results within a twin pair or among multiples. These different aspects are discussed below while recognizing that many issues remain unresolved.

  3. Age and sex-specific mortality of wild and captive populations of a monogamous pair-bonded primate (Aotus azarae)

    DEFF Research Database (Denmark)

    Larson, Sam; Colchero, Fernando; Jones, Owen

    2016-01-01

    In polygynous primates, a greater reproductive variance in males has been linked to their reduced life expectancy relative to females. The mortality patterns of monogamous pair-bonded primates, however, are less clear. We analyzed the sex differences in mortality within wild (NMales = 70, NFemales...... = 73) and captive (NMales = 25, NFemales = 29) populations of Azara's owl monkeys (Aotus azarae), a socially and genetically monogamous primate exhibiting bi-parental care. We used Bayesian Survival Trajectory Analysis (BaSTA) to test age-dependent models of mortality. The wild and captive populations...

  4. Ventricular strain changes in monochorionic twins with and without twin-to-twin transfusion syndrome.

    Science.gov (United States)

    Taylor-Clarke, Marisa C; Matsui, Hikoro; Roughton, Michael; Wimalasundera, Ruwan C; Gardiner, Helena M

    2013-06-01

    The objective of the study was to investigate whether vector velocity imaging (VVI), a non-Doppler speckle tracking ultrasound technology, is feasible in twin pregnancies and can aid management of twin-twin transfusion syndrome (TTTS). Twenty-seven women pregnant with monochorionic diamniotic twins affected by TTTS and 28 monochorionic pregnancies that did not develop TTTS were included in a prospective case-control study at a fetal medicine center. Fetal echocardiograms were recorded with dummy electrocardiography to retain original frame rates when exported for offline speckle tracking analysis using Syngo-VVI software (Siemens Corp, Munich, Germany). Right and left ventricular (LV) free wall Lagrangian strain was measured from the original coordinates. Within-twin pair ventricular strain differences including relationship to Quintero staging and response to laser therapy for TTTS were analyzed by Wilcoxon signed-rank test. The VVI strain measurements could be analyzed in 182 of 200 TTTS and 96 of 112 non-TTTS control ventricles. Within-pair strain was concordant in non-TTTS controls. Recipient LV strain was reduced at all Quintero stages compared with donors (P < .01). Recipient right ventricular strain was reduced only in stages 3 and 4 (P < .01). Strain improved at a median of 2 weeks following successful laser therapy. Intertwin differences in strain were independent of weight discordance. Recipient LV strain is reduced in stages 1 and 2 TTTS. Within-pair strain discordance may distinguish early TTTS from growth discordance and guide timing of and management following treatment. Copyright © 2013 Mosby, Inc. All rights reserved.

  5. Gray and white matter density changes in monozygotic and same-sex dizygotic twins discordant for schizophrenia using voxel-based morphometry

    DEFF Research Database (Denmark)

    Hulshoff Pol, HE; Schnack, HG; Mandl, RC

    2006-01-01

    Global gray matter brain tissue volume decreases in schizophrenia have been associated to disease-related (possibly nongenetic) factors. Global white matter brain tissue volume decreases were related to genetic risk factors for the disease. However, which focal gray and white matter brain regions...... best reflect the genetic and environmental risk factors in the brains of patients with schizophrenia remains unresolved. 1.5-T MRI brain scans of 11 monozygotic and 11 same-sex dizygotic twin-pairs discordant for schizophrenia were compared to 11 monozygotic and 11 same-sex dizygotic healthy control...... twin-pairs using voxel-based morphometry. Linear regression analysis was done in each voxel for the average and difference in gray and white matter density separately, in each twin-pair, with group (discordant, healthy) and zygosity (monozygotic, dizygotic) as between subject variables, and age, sex...

  6. Conjoined twin piglets with duplicated cranial and caudal axes.

    Science.gov (United States)

    McManus, C A; Partlow, G D; Fisher, K R

    1994-06-01

    Twins with doubling of the cranial and caudal poles, yet having a single thorax, are rare. One set of diprosopus, dipygus porcine conjoined twins was studied. In addition to the conjoining anomaly, these twins also exhibited ambiguous internal reproductive features. The twins had two snouts, three eyes, a single thorax, and were duplicated from the umbilicus caudally. Radiography indicated a single vertebral column in the cervical region. The vertebral columns were separate caudally from this point. There was a total of six limbs--one pair of forelimbs and two pairs of hindlimbs. Many medial structures failed to develop in these twins. Medial cranial nerves V-XII were absent or displaced although apparently normal laterally. The medial palates were present but shortened, whereas the medial mandibular rami had folded back on themselves rostrally to form a midline mass between the two chins. Each twin had only one lateral kidney and one lateral testis. Medial scrotal sacs were present but devoid of a testis. There was a midline, "uterine"-like structure which crossed between the twins. However, histological analysis of this structure revealed it to be dysplastic testicular tissue. The relationship between the abnormal reproductive features in these twins and the conjoining is unclear. The anatomy of these twins, in addition to the literature reviewed, illustrates the internal anatomical heterogeneity of grossly similar conjoined twins. A review of the literature also suggests that conjoined twinning may be more common in swine than was previously suspected.

  7. Differential Nongenetic Impact of Birth Weight Versus Third-Trimester Growth Velocity on Glucose Metabolism and Magnetic Resonance Imaging Abdominal Obesity in Young Healthy Twins

    DEFF Research Database (Denmark)

    Pilgaard, Kasper; Mosbech, Thomas Hammershaimb; Grunnet, Louise

    2011-01-01

    Context: Low birth weight is associated with type 2 diabetes, which to some extent may be mediated via abdominal adiposity and insulin resistance. Fetal growth velocity is high during the third trimester, constituting a potential critical window for organ programming. Intra-pair differences among......-pair differences in young healthy twins.Methods: Fifty-eight healthy twins (42 monozygotic/16 dizygotic) aged 18-24 yr participated. Insulin sensitivity was assessed using hyperinsulinemic-euglycemic clamps. Whole-body fat was assessed by dual-energy x-ray absorptiometry scan, whereas abdominal visceral and sc fat...

  8. Familial aggregation of atrial fibrillation: a study in Danish twins

    DEFF Research Database (Denmark)

    Christophersen, Ingrid Elisabeth; Ravn, Lasse Steen; Budtz-Joergensen, Esben

    2009-01-01

    BACKGROUND: Heritability may play a role in nonfamilial atrial fibrillation (AF). We hypothesized that a monozygotic (MZ) twin whose co-twin was diagnosed with AF would have an increased risk of the disease compared with a dizygotic (DZ) twin in the same situation. METHODS AND RESULTS: A sample......-free survival times, we compared the time span between occurrences of disease in MZ and DZ twins. The unaffected twin was included when his or her twin-sibling (the index twin) was diagnosed with AF. After adjustment for age at entry, MZ twins had a significantly shorter event-free survival time (hazard ratio......, 2.0; 95% CI, 1.3 to 3.0), thereby indicating a genetic component. Using biometric models, we estimated the heritability of AF to be 62% (55% to 68%), due to additive genetics. There were no significant differences across sexes. CONCLUSIONS: All the analyses of twin similarities in the present study...

  9. Modeling acardiac twin pregnancies

    NARCIS (Netherlands)

    de Groot, Rosa; van den Wijngaard, Jeroen P. H. M.; Umur, Asli; Beek, Johan F.; Nikkels, Peter G. J.; van Gemert, Martin J. C.

    2007-01-01

    Acardiac twin pregnancies are a rare but severe complication of monochorionic twinning, where the acardiac twin lacks cardiac function but nevertheless grows during pregnancy because it is perfused by the pump twin through a set of placental arterioarterial and venovenous anastomoses. Because the

  10. Stability in symptoms of anxiety and depression as a function of genotype and environment: a longitudinal twin study from ages 3 to 63 years.

    Science.gov (United States)

    Nivard, M G; Dolan, C V; Kendler, K S; Kan, K J; Willemsen, G; van Beijsterveldt, C E M; Lindauer, R J L; van Beek, J H D A; Geels, L M; Bartels, M; Middeldorp, C M; Boomsma, D I

    2015-04-01

    The influence of genetic factors on major depressive disorder is lower than on other psychiatric disorders. Heritability estimates mainly derive from cross-sectional studies, and knowledge on the longitudinal aetiology of symptoms of anxiety and depression (SxAnxDep) across the lifespan is limited. We aimed to assess phenotypic, genetic and environmental stability in SxAnxDep between ages 3 and 63 years. We used a cohort-sequential design combining data from 49 524 twins followed from birth to age ⩾20 years, and from adolescence into adulthood. SxAnxDep were assessed repeatedly with a maximum of eight assessments over a 25-year period. Data were ordered in 30 age groups and analysed with longitudinal genetic models. Over age, there was a significant increase during adolescence in mean scores with sex differences (women>men) emerging. Heritability was high in childhood and decreased to 30-40% during adulthood. This decrease in heritability was due to an increase in environmental variance. Phenotypic stability was moderate in children (correlations across ages ~0.5) and high in adolescents (r = 0.6), young adults (r = 0.7), and adults (r = 0.8). Longitudinal stability was mostly attributable to genetic factors. During childhood and adolescence there was also significant genetic innovation, which was absent in adults. Environmental effects contributed to short-term stability. The substantial stability in SxAnxDep is mainly due to genetic effects. The importance of environmental effects increases with age and explains the relatively low heritability of depression in adults. The environmental effects are transient, but the contribution to stability increases with age.

  11. Differential models of twin correlations in skew for body-mass index (BMI).

    Science.gov (United States)

    Tsang, Siny; Duncan, Glen E; Dinescu, Diana; Turkheimer, Eric

    2018-01-01

    Body Mass Index (BMI), like most human phenotypes, is substantially heritable. However, BMI is not normally distributed; the skew appears to be structural, and increases as a function of age. Moreover, twin correlations for BMI commonly violate the assumptions of the most common variety of the classical twin model, with the MZ twin correlation greater than twice the DZ correlation. This study aimed to decompose twin correlations for BMI using more general skew-t distributions. Same sex MZ and DZ twin pairs (N = 7,086) from the community-based Washington State Twin Registry were included. We used latent profile analysis (LPA) to decompose twin correlations for BMI into multiple mixture distributions. LPA was performed using the default normal mixture distribution and the skew-t mixture distribution. Similar analyses were performed for height as a comparison. Our analyses are then replicated in an independent dataset. A two-class solution under the skew-t mixture distribution fits the BMI distribution for both genders. The first class consists of a relatively normally distributed, highly heritable BMI with a mean in the normal range. The second class is a positively skewed BMI in the overweight and obese range, with lower twin correlations. In contrast, height is normally distributed, highly heritable, and is well-fit by a single latent class. Results in the replication dataset were highly similar. Our findings suggest that two distinct processes underlie the skew of the BMI distribution. The contrast between height and weight is in accord with subjective psychological experience: both are under obvious genetic influence, but BMI is also subject to behavioral control, whereas height is not.

  12. Anorexia and Bulimia Nervosa in Same-Sex and Opposite-Sex Twins : Lack of Association With Twin Type in a Nationwide Study of Finnish Twins

    NARCIS (Netherlands)

    Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W.; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

    2008-01-01

    Objective: The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Method: Finnish twins (N=2,426 women,

  13. Genetic and environmental influences on adolescents' smoking involvement: a multi-informant twin study.

    Science.gov (United States)

    Seglem, Karoline Brobakke; Waaktaar, Trine; Ask, Helga; Torgersen, Svenn

    2015-03-01

    Studying monozygotic and dizygotic adolescent twin pairs of both sexes reared together, the present study examined the extent to which the variance in smoking involvement is attributable to genetic and environmental effects, and to what extent there are sex differences in the etiology. Questionnaire data on how often the adolescent had ever smoked tobacco was collected from a population-based twin sample consisting of seven national birth cohorts (ages 12-18), their mothers, and their fathers (N = 1,394 families). The data was analyzed with multivariate genetic modeling, using a multi-informant design. The etiological structure of smoking involvement was best represented in an ACE common pathway model, with smoking defined as a latent factor loading onto all three informants' reports. Estimates could be set equal across sexes. Results showed that adolescent lifetime smoking involvement was moderately heritable (37 %). The largest influence was from the shared environment (56 %), while environmental effects unique to each twin had minimal influence (7 %).

  14. A longitudinal twin study on IQ, executive functioning, and attention problems during childhood and early adolescence.

    Science.gov (United States)

    Polderman, Tinca J C; Gosso, M Florencia; Posthuma, Danielle; Van Beijsterveldt, Toos C E M; Heutink, Peter; Verhulst, Frank C; Boomsma, Dorret I

    2006-12-01

    Variation in human behavior may be caused by differences in genotype and by non-genetic differences ("environment") between individuals. The relative contributions of genotype (G) and environment (E) to phenotypic variation can be assessed with the classical twin design. We illustrate this approach with longitudinal data collected in 5 and 12-year-old Dutch twins. At age 5 data on cognitive abilities as assessed with a standard intelligence test (IQ), working memory, selective and sustained attention, and attention problems were collected in 237 twin pairs. Seven years later, 172 twin pairs participated again when they were 12 years old and underwent a similar protocol. Results showed that variation in all phenotypes was influenced by genetic factors. For IQ the heritability estimates increased from 30% at age 5, to 80% at age 12. For executive functioning performance genetic factors accounted for around 50% of the variance at both ages. Attention problems showed high heritabilities (above 60%) at both ages, for maternal and teacher ratings. Longitudinal analyses revealed that executive functioning during childhood was weakly correlated with IQ scores at age 12. Attention problems during childhood, as rated by the mother and the teacher were stronger predictors (r = -0.28 and -0.36, respectively). This association could be attributed to a partly overlapping set of genes influencing attention problems at age 5 and IQ at age 12. IQ performance at age 5 was the best predictor of IQ at age 12. IQ at both ages was influenced by the same genes, whose influence was amplified during development.

  15. Adolescent idiopathic scoliosis in twins: a population-based survey

    DEFF Research Database (Denmark)

    Andersen, Mikkel O; Thomsen, Karsten; Kyvik, Kirsten O

    2007-01-01

    STUDY DESIGN: A questionnaire-based identification of adolescent idiopathic scoliosis (AIS) patients in a twin cohort. OBJECTIVE: The purpose of this study was to establish a scoliosis twin cohort to provide data on the heritability of AIS. SUMMARY OF BACKGROUND DATA: The etiology of AIS is still...... environmental factors. METHODS: All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a questionnaire, which included questions about scoliosis. A total of 34,944 (75.3%) representing 23,204 pairs returned the questionnaire. RESULTS: A subgroup of 220 subjects considered...... of monozygotic and dizygotic pairs was significantly different (P scoliosis in 1 twin whose other twin has scoliosis is smaller than believed up until now....

  16. Leisure-time physical activity and intra-abdominal fat in young adulthood: A monozygotic co-twin control study.

    Science.gov (United States)

    Rottensteiner, Mirva; Leskinen, Tuija; Järvelä-Reijonen, Elina; Väisänen, Karoliina; Aaltonen, Sari; Kaprio, Jaakko; Kujala, Urho M

    2016-05-01

    To investigate differences in abdominal fat compartments between young adult monozygotic twin pairs discordant for leisure-time physical activity. Ten young adult male monozygotic twin pairs (age range 32-36 years) discordant for leisure-time physical activity during the past 3 years were systematically selected from a population-based Finnish twin cohort. Magnetic resonance image at the level of the L2-L3 intervertebral disc was used to predict intra-abdominal and subcutaneous abdominal fat masses. Dietary intake was assessed with a 4-day food diary. Inactive twins had 31% more intra-abdominal fat than their active co-twins (mean difference 0.52 kg, 95% CI 0.12 to 0.91, P = 0.016), whereas the difference in subcutaneous abdominal fat was only 13% (P = 0.21) and 3% in body mass index (P = 0.28). Intraperitoneal fat mass was 41% higher among inactive twins compared to their active co-twins (mean difference 0.41 kg, 95% CI 0.11 to 0.70, P = 0.012). Dietary intake did not differ between co-twins. A lower level of physical activity is related to greater accumulation of intra-abdominal fat among healthy adult males in their mid-30s. The findings highlight the importance of leisure-time physical activity independent of genes and diet in the prevention of intra-abdominal fat accumulation from early adulthood onward. © 2016 The Obesity Society.

  17. Twin study of heritability of eating bread in Danish and Finnish men and women.

    Science.gov (United States)

    Hasselbalch, Ann L; Silventoinen, Karri; Keskitalo, Kaisu; Pietiläinen, Kirsi H; Rissanen, Aila; Heitmann, Berit L; Kyvik, Kirsten O; Sørensen, Thorkild I A; Kaprio, Jaakko

    2010-04-01

    Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. The study cohorts included 575 Danish (age range 18-67 years) and 2009 Finnish (age range 22-27 years) adult twin pairs. Self-reported frequency of eating bread was obtained by food frequency questionnaires. Univariate models based on linear structural equations for twin data were used to estimate the relative magnitude of the additive genetic, shared environmental and individual environmental effects on bread eating frequency and choice of bread. The analysis of bread intake frequency demonstrated moderate heritability ranging from 37-40% in the Finnish cohort and 23-26% in the Danish cohort. The genetic influence on intake of white bread was moderate (24-31%), while the genetic influence on intake of rye bread was higher in men (41-45%) than in women (24-33%). Environmental influences shared by the twins were not significant. Consumption of bread as well as choice of bread is influenced by genetic predisposition. Environmental factors shared by the co-twins (e.g., childhood environment) seem to have no significant effects on bread consumption and preference in adulthood.

  18. Study of 3-D stress development in parent and twin pairs of a hexagonal close-packed polycrystal: Part I - In-situ three-dimensional synchrotron X-ray diffraction measurement

    DEFF Research Database (Denmark)

    Abdolvand, Hamidreza; Majkut, Marta; Oddershede, Jette

    2015-01-01

    to reconstruct the 3D microstructure and statistically study neighborhood effects on the load sharing. The investigated volume of the sample contained 6132 grains initially, yet as a result of twin formation, 9724 grains were measured in the same volume at the last loading step. It is shown that the most favored......) microscopy. In-situ uniaxial straining was carried out at seven steps up to 2.7% in the macroscopic direction that favors twin formation, while center-of-mass position, crystallographic orientation, elastic strain, stress, and relative volume of each grain were measured. This information was used...

  19. Fetal Environment Is a Major Determinant of the Neonatal Blood Thyroxine Level: Results of a Large Dutch Twin Study.

    Science.gov (United States)

    Zwaveling-Soonawala, Nitash; van Beijsterveldt, Catharina E M; Mesfum, Ertirea T; Wiedijk, Brenda; Oomen, Petra; Finken, Martijn J J; Boomsma, Dorret I; van Trotsenburg, A S Paul

    2015-06-01

    The interindividual variability in thyroid hormone function parameters is much larger than the intraindividual variability, suggesting an individual set point for these parameters. There is evidence to suggest that environmental factors are more important than genetic factors in the determination of this individual set point. This study aimed to quantify the effect of genetic factors and (fetal) environment on the early postnatal blood T4 concentration. This was a classical twin study comparing the resemblance of neonatal screening blood T4 concentrations in 1264 mono- and 2566 dizygotic twin pairs retrieved from the population-based Netherlands Twin Register. Maximum-likelihood estimates of variance explained by genetic and environmental influences were obtained by structural equation modeling in data from full-term and preterm twin pairs. In full-term infants, genetic factors explained 40%/31% of the variance in standardized T4 scores in boys/girls, and shared environment, 27%/22%. The remaining variance of 33%/47% was due to environmental factors not shared by twins. For preterm infants, genetic factors explained 34%/0% of the variance in boys/girls, shared environment 31%/57%, and unique environment 35%/43%. In very preterm twins, no significant contribution of genetic factors was observed. Environment explains a large proportion of the resemblance of the postnatal blood T4 concentration in twin pairs. Because we analyzed neonatal screening results, the fetal environment is the most likely candidate for these environmental influences. Genetic influences on the T4 set point diminished with declining gestational age, especially in girls. This may be due to major environmental influences such as immaturity and nonthyroidal illness in very preterm infants.

  20. Excess Mortality in Patients Diagnosed With Hypothyroidism: A Nationwide Cohort Study of Singletons and Twins

    Science.gov (United States)

    Thvilum, Marianne; Brandt, Frans; Almind, Dorthe; Christensen, Kaare; Brix, Thomas Heiberg

    2013-01-01

    Background: Although hypothyroidism is associated with increased morbidity, an association with increased mortality is still debated. Our objective was to investigate, at a nationwide level, whether a diagnosis of hypothyroidism influences mortality. Methods: In an observational cohort study from January 1, 1978 until December 31, 2008 using record-linkage data from nationwide Danish health registers, 3587 singletons and 682 twins diagnosed with hypothyroidism were identified. Hypothyroid individuals were matched 1:4 with nonhypothyroid controls with respect to age and gender and followed over a mean period of 5.6 years (range 0–30 years). The hazard ratio (HR) for mortality was calculated using Cox regression analyses. Comorbidity was evaluated using the Charlson score (CS). Results: In singletons with hypothyroidism, the mortality risk was increased (HR 1.52; 95% confidence interval [CI]: 1.41–1.65). Although the effect attenuated, hypothyroidism remained associated with increased mortality when evaluating subjects with a CS = 0 (HR 1.23; 95% CI: 1.05–1.44). In twin pairs discordant for hypothyroidism, the hypothyroid twin had excess mortality compared with the corresponding euthyroid cotwin (HR 1.40; 95% CI 0.95–2.05). However, after stratifying for zygosity, hypothyroidism was associated with excess mortality in dizygotic twin pairs (HR 1.61; 95% CI 1.00–2.58), whereas the association attenuated in monozygotic pairs (HR 1.06; 95% CI 0.55–2.05). Conclusions: Hypothyroidism is associated with an excess mortality of around 50%, which to some degree is explained by comorbidity. In addition, the finding of an association between hypothyroidism and mortality within disease discordant dizygotic but not monozygotic twin pairs indicates that the association between hypothyroidism and mortality is also influenced by genetic confounding. PMID:23365121

  1. Influences on achieving motor milestones: A twin-singleton study

    NARCIS (Netherlands)

    Brouwer, S.I.; van Beijsterveldt, C.E.M.; Bartels, M.; Hudziak, J.; Boomsma, D.I.

    2006-01-01

    In order to determine if twinning impacted achievement of motor milestones the attainment of early motor milestones in twins was examined and compared to published data from singletons of the same age from the same culture and birth years. We examined the influence of twinning, sex, zygosity and

  2. Birth weight in opposite sex twins as compared to same sex dizygotic twins

    NARCIS (Netherlands)

    Orlebeke, J.F.; van Baal, G.C.M.; Boomsma, D.I.; Neeleman, D.

    1993-01-01

    The question addressed in the present report is whether the large birth weight differences in dizygotic twin pairs of opposite sex (DZos), especially in 'male first' couples - observed by Blickstein and Weissman (Blickstein I, Weissman A. Birth weight discordancy in male-first and female-first pairs

  3. Hemoglobin Differences in Uncomplicated Monochorionic Twins in Relation to Birth Order and Mode of Delivery.

    Science.gov (United States)

    Verbeek, Lianne; Zhao, Depeng P; Te Pas, Arjan B; Middeldorp, Johanna M; Hooper, Stuart B; Oepkes, Dick; Lopriore, Enrico

    2016-06-01

    To determine the differences in hemoglobin (Hb) levels in the first 2 days after birth in uncomplicated monochorionic twins in relation to birth order and mode of delivery. All consecutive uncomplicated monochorionic pregnancies with two live-born twins delivered at our center were included in this retrospective study. We recorded Hb levels at birth and on day 2, and analyzed Hb levels in association with birth order, mode of delivery, and time interval between delivery of twin 1 and 2. A total of 290 monochorionic twin pairs were analyzed, including 171 (59%) twins delivered vaginally and 119 (41%) twins born by cesarean section (CS). In twins delivered vaginally, mean Hb levels at birth and on day 2 were significantly higher in second-born twins compared to first-born twins: 17.8 versus 16.1 g/dL and 18.0 versus 14.8 g/dL, respectively (p < .01). Polycythemia was detected more often in second-born twins (12%, 20/166) compared to first-born twins (1%, 2/166; p < .01). Hb differences within twin pairs delivered by CS were not statistically or clinically significant. We found no association between inter-twin delivery time intervals and Hb differences. Second-born twins after vaginal delivery have higher Hb levels and more often polycythemia than their co-twin, but not when born by CS.

  4. Conjoined twins detected in the first trimester: A review

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chen

    2011-12-01

    Full Text Available Conjoined twinning occurs in 1 in 100 sets of monozygotic twins, 1 in 50,000 gestations or 1 in 250,000 live births. With the advent of ultrasound technology, prenatal diagnosis of conjoined twins is possible. This article provides a comprehensive review of conjoined twins detected in the first trimester including fetal gender, maternal age, parity, types of fusion, related ultrasound abnormalities, perinatal outcome and association with assisted reproduction.

  5. Dichorionic Diamniotic Twin Pregnancy Discordant for Bladder Exstrophy

    Directory of Open Access Journals (Sweden)

    William Tu

    2009-01-01

    Full Text Available A 38 year-old woman presented with a dichorionic diamniotic twin pregnancy at gestational age of 32 weeks concerning for an abdominal wall mass in one of the twins. Initial ultrasound evaluation was suspicious for an omphalocele, but the affected twin was found to have bladder exstrophy at birth. This illustrates the difficulties of accurate prenatal diagnosis of bladder exstrophy in a twin pregnancy at a late gestation.

  6. Time trends in the natural dizygotic twinning rate.

    Science.gov (United States)

    Derom, Catherine; Gielen, Marij; Peeters, Hilde; Frijns, Jean-Pierre; Zeegers, Maurice P A

    2011-08-01

    The natural dizygotic (DZ) twinning rate has been proposed as a reliable and useful measure of human fecundity, if adjusted for maternal age at twin birth. The aim of this study was to analyze age-adjusted trends in natural DZ twinning rates over the past 40 years using data from the 'East Flanders Prospective Twin Survey (EFPTS)'. This study involved 4835 naturally conceived twin pregnancies between 1969 and 2009 from the population-based Belgian 'EFPTS'. Age-adjusted trends in the incidence of natural DZ twin pregnancies were calculated using a generalized linear model with Poisson distribution. Both the natural DZ twinning rates and maternal age at twin birth increased in a linear fashion from 1969 to 2009. When age-adjusted, we found that the trend in the natural DZ twinning rate was stable during the whole time period. According to our population-based data and after age-adjustment, a stable natural DZ twinning rate could be observed over the last four decades. Under the assumption that the spontaneous DZ twinning rate is a sensor of fecundity, this indicates a stable 'high' fecundity for this population.

  7. Epidemiological and clinical analysis of a consecutive series of conjoined twins in Spain.

    Science.gov (United States)

    Martínez-Frías, María Luisa; Bermejo, Eva; Mendioroz, Jacobo; Rodríguez-Pinilla, Elvira; Blanco, Manuel; Egüés, Javier; Félix, Valentín; García, Angel; Huertas, Héctor; Nieto, Carmen; López, José Antonio; López, Santiago; Paisán, Luis; Rosa, Alejandro; Vázquez, María Socorro

    2009-04-01

    frequent type observed was thoracopagus, with an overall prevalence at birth of 0.44 per 100,000 (1/228,160) from 1980 to 2006, representing 58.82% of the total population of symmetric conjoined twin pairs. Diprosopus pairs were the next most common group (11.76%). Most of the cases were females (4 males/11 females), and although this appeared to be mainly because of the thoracopagus pairs (males-females, 2:8), in such a small number of cases, it is not possible to determine the ratios for the other groups. Gestational age was significantly shorter than in control twins for each type studied. We conclude that it is incorrect to consider that all types of conjoined twins have the same epidemiological characteristics, such as the frequency at birth. The differences observed may be related with the distinct embryo-fetal mortality of each type of conjoined twins in different populations, and the sex ratio, among others.

  8. Socio-psycho-historical observation on the twin

    International Nuclear Information System (INIS)

    Watanabe, Shoji; Satow, Yukio; Ueoka, Hiroshi; Munaka, Masaki; Kurihara, Minoru

    1980-01-01

    The so-called ''twin control study'', mainly on the monozygotic twins one of which was A-bomb exposed and the other was non-exposed were carried out. Sampling was conducted utilizing the materials as follows: 1) The survey on casualities of A-bomb exposed families in Hiroshima which was undertaken in 1946. 2) The survey of A-bomb survivors in 1965. 3) A-bomb exposed family survey conducted between 1973 to 1975. 4) Investigations of A-bomb victims exposed in the proximal areas from the hypocenter. From the above mentioned materials 470 pairs were selected, of which 220 were exposed. Among them 172 pairs were twins of the same sex. Female and male pair were also employed. In one case they were exposed, while the others were nonexposed. Two pairs were examined under the following methods: 1) Depth interview to ascertain familial casualities with reference to the family life cycle. 2) Socio-historical research. 3) Motoaki's Jinkaku Shindan Kensa (Modified Rorschach test by H. Motoaki), and T.A.T. test. Results obtained were summarized as follows: 1) Both pairs of twins were similar appearance, and also personality traits, and had a strong feeling of companionship for each other. 2) In family relationships, the persons studied were very conscious of the role expectations of elder and younger siblings in the twin pairs. 3) Through depth interview and projective test, A-bomb exposed pairs still showed deep psychological stresses, resulting from the A-bomb disaster. 4) Both among the exposed twins and within the nonexposed control group twin siblings had a close feeling of companionship for each other. However, nonexposed twins could not understand the psychological experience of twins who had been subjected to the atomic disaster. (author)

  9. Bidirectional Influences between Maternal Parenting and Children's Peer Problems: A Longitudinal Monozygotic Twin Difference Study

    Science.gov (United States)

    Yamagata, Shinji; Takahashi, Yusuke; Ozaki, Koken; Fujisawa, Keiko K.; Nonaka, Koichi; Ando, Juko

    2013-01-01

    This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin…

  10. Cancer risk in opposite-sex and same-sex twins

    DEFF Research Database (Denmark)

    Juel Ahrenfeldt, Linda

    2015-01-01

    Twin pregnancies are characterized by simultaneous development of two fetuses that share the womb. An interest in opposite-sex (OS) twins, twin pairs consisting of one male and one female, comes from animal studies that showed that exposure to sex hormones is influenced by the position of the fetus...

  11. The Heritability of Breast Cancer among women in the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    Möller, Sören; Mucci, Lorelei A; Harris, Jennifer R

    2016-01-01

    and heritability of breast cancer among 21,054 monozygotic and 30,939 dizygotic female twin pairs from the Nordic Twin Study of Cancer, the largest twin study of cancer in the world. We accounted for left-censoring, right-censoring, as well as the competing risk of death. Results From 1943 through 2010, 3...

  12. Traces of embryogenesis are the same in monozygotic and dizygotic twins: not compatible with double ovulation.

    Science.gov (United States)

    Boklage, Charles E

    2009-06-01

    Common knowledge of over a century has it that monozygotic and dizygotic twinning events occur by unrelated mechanisms: monozygotic twinning 'splits' embryos, producing anomalously re-arranged embryogenic asymmetries; dizygotic twinning begins with independent ovulations yielding undisturbed parallel embryogeneses with no expectation of departures from singleton outcomes. The anomalies statistically associated with twin births are due to the re-arranged embryos of the monozygotics. Common knowledge further requires that dizygotic pairs are dichorionic; monochorionicity is exclusive to monozygotic pairs. These are fundamental certainties in the literature of twin biology. Multiple observations contradict those common knowledge understandings. The double ovulation hypothesis of dizygotic twinning is untenable. Girl-boy twins differ subtly from all other humans of either sex, absolutely not representative of all dizygotics. Embryogenesis of dizygotic twins differs from singleton development at least as much as monozygotic embryogenesis does, and in the same ways, and the differences between singletons and twins of both zygosities represent a coherent system of re-arranged embryogenic asymmetries. Dizygotic twinning and monozygotic twinning have the same list of consequences of anomalous embryogenesis. Those include an unignorable fraction of dizygotic pairs that are in fact monochorionic, plus many more sharing co-twins' cells in tissues other than a common chorion. The idea that monozygotic and dizygotic twinning events arise from the same embryogenic mechanism is the only plausible hypothesis that might explain all of the observations.

  13. Dichorionic triamniotic triplet pregnancy complicated by twin anemia polycythemia sequence: the place of fetal therapy.

    Science.gov (United States)

    Griersmith, Thérèse H; Fung, Alison M; Walker, Susan P

    2014-12-01

    Monochorionic twins as part of a high order multiple pregnancy can be an unintended consequence of the increasingly common practice of blastocyst transfer for couples requiring in vitro fertilisation (IVF) for infertility. Dichorionic triamniotic (DCTA) triplets is the most common presentation, and these pregnancies are particularly high risk because of the additional risks associated with monochorionicity. Surveillance for twin-to-twin transfusion syndrome, including twin anemia polycythemia sequence, may be more difficult, and any intervention to treat the monochorionic pair needs to balance the proposed benefits against the risks posed to the unaffected singleton. Counseling of families with DCTA triplets is therefore complex. Here, we report a case of DCTA triplets, where the pregnancy was complicated by threatened preterm labour, and twin anemia polycythemia sequence (TAPS) was later diagnosed at 28 weeks. The TAPS was managed with a single intraperitoneal transfusion, enabling safe prolongation of the pregnancy for over 2 weeks until recurrence of TAPS and preterm labour supervened. Postnatal TAPS was confirmed, and all three infants were later discharged home at term corrected age, and were normal at follow-up. This case highlights that in utero therapy has an important role in multiple pregnancies of mixed chorionicity, and can achieve safe prolongation of pregnancy at critical gestations.

  14. Hyper-Binding across Time: Age Differences in the Effect of Temporal Proximity on Paired-Associate Learning

    Science.gov (United States)

    Campbell, Karen L.; Trelle, Alexandra; Hasher, Lynn

    2014-01-01

    Older adults show hyper- (or excessive) binding effects for simultaneously and sequentially presented distraction. Here, we addressed the potential role of hyper-binding in paired-associate learning. Older and younger adults learned a list of word pairs and then received an associative recognition task in which rearranged pairs were formed from…

  15. Socio-psycho-historical observation on the twin. Sampling methods and case study of the atomic bomb exposed twins

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S; Satow, Y; Ueoka, Hiroshi; Munaka, M; Kurihara, M [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

    1980-07-01

    The so-called ''twin control study'', mainly on the monozygotic twins one of which was A-bomb exposed and the other was non-exposed were carried out. Sampling was conducted utilizing the materials as follows: 1) The survey on casualities of A-bomb exposed families in Hiroshima which was undertaken in 1946. 2) The survey of A-bomb survivors in 1965. 3) A-bomb exposed family survey conducted between 1973 to 1975. 4) Investigations of A-bomb victims exposed in the proximal areas from the hypocenter. From the above mentioned materials 470 pairs were selected, of which 220 were exposed. Among them 172 pairs were twins of the same sex. Female and male pair were also employed. In one case they were exposed, while the others were nonexposed. Two pairs were examined under the following methods: 1) Depth interview to ascertain familial casualities with reference to the family life cycle. 2) Socio-historical research. 3) Motoaki's Jinkaku Shindan Kensa (Modified Rorschach test by H. Motoaki), and T.A.T. test. Results obtained were summarized as follows: 1) Both pairs of twins were of similar appearance and personality traits, and had a strong feeling of companionship for each other. 2) In family relationships, the persons studied were very conscious of the role expectations of elder and younger siblings in the twin pairs. 3) Through depth interviews and projective tests, A-bomb exposed pairs still showed deep psychological stresses, resulting from the A-bomb disaster. 4) Both among the exposed twins and within the nonexposed control group twin siblings had a close feeling of companionship for each other. However, nonexposed twins could not understand the psychological experience of twins who had been subjected to the atomic disaster.

  16. Association of Depressive Symptoms and Heart Rate Variability in Vietnam War-Era Twins: A Longitudinal Twin Difference Study.

    Science.gov (United States)

    Huang, Minxuan; Shah, Amit; Su, Shaoyong; Goldberg, Jack; Lampert, Rachel J; Levantsevych, Oleksiy M; Shallenberger, Lucy; Pimple, Pratik; Bremner, J Douglas; Vaccarino, Viola

    2018-05-16

    Depressive symptoms are associated with lower heart rate variability (HRV), an index of autonomic dysregulation, but the direction of the association remains unclear. To investigate the temporal association between depression and HRV. A longitudinal, cross-lagged twin difference study, with baseline assessments from March 2002 to March 2006 (visit 1) and a 7-year follow-up (visit 2) at an academic research center with participants recruited from a national twin registry. Twins (n = 166) from the Vietnam Era Twin Registry, who served in the US military during the Vietnam War, and were discordant for depression at baseline were recruited. At both visits, depressive symptoms were measured using the Beck Depression Inventory-II (BDI-II), and HRV was measured through 24-hour electrocardiogram monitoring. To assess the direction of the association, within-pair differences in multivariable mixed-effects regression models were examined, and standardized β coefficients for both pathways were calculated. The associations were evaluated separately in monozygotic and dizygotic twins. In the final analytic sample (N = 146), all participants were men, 138 (95%) were white, and the mean (SD) age was 54 (3) years at baseline. Results showed consistent associations between visit 1 HRV and visit 2 BDI score across all HRV domains and models (β coefficients ranging from -0.14 to -0.29), which were not explained by antidepressants or other participant characteristics. The magnitude of the association was similar in the opposite pathway linking visit 1 BDI score to visit 2 HRV, with β coefficients ranging from 0.05 to -0.30, but it was largely explained by antidepressant use. In stratified analysis by zygosity, significant associations were observed in monozygotic and dizygotic twins for the path linking visit 1 HRV to visit 2 BDI score, although the associations were slightly stronger in dizygotic twins. The association between depression and autonomic dysregulation

  17. Relationship between refractive error and ocular biometrics in twin children: the Guangzhou Twin Eye Study.

    Science.gov (United States)

    Wang, Decai; Liu, Bin; Huang, Shengsong; Huang, Wenyong; He, Mingguang

    2014-09-01

    A cross-sectional study was conducted to explore the relationship between refractive error and ocular biometrics in children from the Guangzhou twin eye study. Twin participants aged 7-15 years were selected from Guangzhou Twin Eye Study. Ocular examinations included visual acuity measurement, ocular motility evaluation, autorefraction under cycloplegia, and anterior segment, media, and fundus examination. Axial length (AL), anterior chamber depth (ACD), and corneal curvature radius were measured using partial coherence laser interferometry. A multivariate linear regression model was used for statistical analysis. Twin children from Guangzhou city showed a decreased spherical equivalent with age, whereas both AL and ACD were increased and corneal curvature radius remained unchanged. When adjusted by age and gender, the data from 77% of twins presenting with spherical equivalent changes indicated that these were caused by predictable variables (R2 = 0.77, P biometrics. Refractive status is largely determined by axial length as the major factor.

  18. Concordance Rates of Adolescent Idiopathic Scoliosis in a Danish Twin Population

    DEFF Research Database (Denmark)

    Simony, Ane; Carreon, Leah Y; Højmark, Karen

    2016-01-01

    STUDY DESIGN: Clinical, radiological and genetic determination of zygosity of twin pairs from the Danish Twin Registry who self-reported having Adolescent Idiopathic Scoliosis (AIS). OBJECTIVE: To establish concordance rates of AIS. SUMMARY OF BACKGROUND DATA: The aetiology of and the true mode...... reported. METHODS: All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a survey, which included questions about scoliosis. The survey was returned by 34,944 individuals (75.3%) representing 23,204 pairs. From this study, 548 individuals representing 274 complete twin...... pairs where at least one twin self-reported having scoliosis were invited to a clinical and radiological examination. Zygosity was established by genetic testing. RESULTS: 182 individuals (33.2%) of the original cohort agreed to participate, 128 of whom had scoliosis by self-report. There were 91 twin...

  19. [A co-twin control study on birth weight, overweight and obesity among children younger than 18 years old in China].

    Science.gov (United States)

    Liu, Qingqing; Yu, Canqing; Gao, Wenjing; Cao, Weihua; Lyu, Jun; Wang, Shengfeng; Pang, Zengchang; Cong, Liming; Dong, Zhong; Wu, Fan; Wang, Hua; Wu, Xianping; Wang, Dezheng; Wang, Binyou; Li, Liming

    2016-04-01

    To analyze the associations between birth weight and overweight/obesity among children. A total of 8 267 twin pairs younger than 18 years old from the Chinese National Twin Registry were included in the study. Associations between birth weight, childhood BMI and overweight/obesity were explored by this co-twin control study. After adjusting for sex and zygosity, when birth weight had an increase of 0.5 kg per fold, the OR values for overweight and obesity were 1.87(95%CI: 1.40-2.48) for 2-6 year olds, 1.69 (95%CI: 1.16-2.46) for 6-12 year olds and 1.28 (95%CI: 0.80-2.07) for 12-18 year olds. from the stratified analysis in the 2-6 year-olds, statistically significant differences were seen. When birth weight increased 0.5 kg per fold, the risk of overweight and obesity increased by 0.87 times among the dizygotic twins, more than that of the monozygotic twins (OR=1.86, 95%CI:1.24-2.81). The risk for male twins was 1.12 times higher than that of female twins (OR=1.65, 95%CI:1.11-2.44). Birth weight seemed associated with overweight and obesity for kids at early childhood or at age for schools. However, guidance on the implementation of public health interventions is still needed on these children.

  20. Enhanced production of low-mass electron-positron pairs in 40-AGeV Pb-Au collisions at the CERN SPS.

    Science.gov (United States)

    Adamová, D; Agakichiev, G; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Cherlin, A; Damjanović, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Z; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B; Maas, A; Marín, A; Milosević, J; Milov, A; Miśkowiec, D; Panebrattsev, Yu; Petchenova, O; Petrácek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Richter, M; Sako, H; Schmitz, W; Sedykh, S; Seipp, W; Sharma, A; Shimansky, S; Slívová, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, I; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V

    2003-07-25

    We report on first measurements of low-mass electron-positron pairs in Pb-Au collisions at the CERN SPS beam energy of 40 AGeV. The observed pair yield integrated over the range of invariant masses 0.2e(+)e(-) annihilation with a modified rho propagator. They may be linked to chiral symmetry restoration and support the notion that the in-medium modifications of the rho are more driven by baryon density than by temperature.

  1. Enhanced production of low-mass electron-positron pairs in 40-AGeV Pb-Au collisions at the CERN SPS

    CERN Document Server

    Adamova, D; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B C; Maas, A; Marin, A; Milosevic, J; Milov, A; Miskowiec, D; Panebratsev, Yu A; Petchenova, O Yu; Petracek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Richter, M; Sako, H; Schmitz, W; Sedykh, S; Seipp, W; Sharma, A; Shimansky, S S; Slivova, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V I

    2003-01-01

    We report on first measurements of low-mass electron pairs in Pb-Au collisions at the lower SPS beam energy of 40 AGeV. The pair yield integrated over the range of invariant masses 0.2 e+ e- annihilation with a modified rho-propagator. They may be linked to chiral symmetry restoration and support the notion that the in-medium modifications of the rho are more driven by baryon density than by temperature.

  2. Grammar Clinical Marker Yields Substantial Heritability for Language Impairments in 16-Year-Old Twins.

    Science.gov (United States)

    Dale, Philip S; Rice, Mabel L; Rimfeld, Kaili; Hayiou-Thomas, Marianna E

    2018-01-22

    There is a need for well-defined language phenotypes suitable for adolescents in twin studies and other large-scale research projects. Rice, Hoffman, and Wexler (2009) have developed a grammatical judgment measure as a clinical marker of language impairment, which has an extended developmental range to adolescence. We conducted the first twin analysis, along with associated phenotypic analyses of validity, of an abridged, 20-item version of this grammatical judgment measure (GJ-20), based on telephone administration using prerecorded stimuli to 405 pairs of 16-year-olds (148 monozygotic and 257 dizygotic) drawn from the Twins Early Development Study (Haworth, Davis, & Plomin, 2012). The distribution of scores is markedly skewed negatively, as expected for a potential clinical marker. Low performance on GJ-20 is associated with lower maternal education, reported learning disability (age 7 years), and low scores on language tests administered via the Twins Early Development Study (age 16 years) as well as General Certificate of Secondary Education English and Math examination performance (age 16 years). Liability threshold estimates for the genetic influence on low performance on GJ-20 are substantial, ranging from 36% with a lowest 10% criterion to 74% for a lowest 5% criterion. The heritability of GJ-20 scores, especially at more extreme cutoffs, along with the score distribution and association with other indicators of language impairments, provides additional evidence for the potential value of this measure as a clinical marker of specific language impairment.

  3. Examination of the Relationship between Oral Health and Arterial Sclerosis without Genetic Confounding through the Study of Older Japanese Twins.

    Directory of Open Access Journals (Sweden)

    Yuko Kurushima

    Full Text Available Although researchers have recently demonstrated a relationship between oral health and arterial sclerosis, the genetic contribution to this relationship has been ignored even though genetic factors are expected to have some effect on various diseases. The aim of this study was to evaluate oral health as a significant risk factor related to arterial sclerosis after eliminating genetic confounding through study of older Japanese twins.Medical and dental surveys were conducted individually for 106 Japanese twin pairs over the age of 50 years. Maximal carotid intima-media thickness (IMT-Cmax was measured as a surrogate marker of arterial sclerosis. IMT-Cmax > 1.0 mm was diagnosed as arterial sclerosis. All of the twins were examined for the number of remaining teeth, masticatory performance, and periodontal status. We evaluated each measurement related with IMT-Cmax and arterial sclerosis using generalized estimating equations analysis adjusted for potential risk factors. For non-smoking monozygotic twins, a regression analysis using a "between within" model was conducted to evaluate the relationship between IMT-Cmax and the number of teeth as the environmental factor controlling genetic and familial confounding.We examined 91 monozygotic and 15 dizygotic twin pairs (males: 42, females: 64 with a mean (± standard deviation age of 67.4 ± 10.0 years. Out of all of the oral health-related measurements collected, only the number of teeth was significantly related to arterial sclerosis (odds ratio: 0.72, 95% confidence interval: 0.52-0.99 per five teeth. Regression analysis showed a significant association between the IMT-Cmax and the number of teeth as an environmental factor (p = 0.037.Analysis of monozygotic twins older than 50 years of age showed that having fewer teeth could be a significant environmental factor related to arterial sclerosis, even after controlling for genetic and familial confounding.

  4. Disease-Concordant Twins Empower Genetic Association Studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Li, Weilong; Vandin, Fabio

    2017-01-01

    and ordinary healthy samples as controls. We examined the power gain of the twin-based design for various scenarios (i.e., cases from monozygotic and dizygotic twin pairs concordant for a disease) and compared the power with the ordinary case-control design with cases collected from the unrelated patient...... concordant for a disease, should confer increased power in genetic association analysis because of their genetic relatedness. We conducted a computer simulation study to explore the power advantage of the disease-concordant twin design, which uses singletons from disease-concordant twin pairs as cases...... population. Simulation was done by assigning various allele frequencies and allelic relative risks for different mode of genetic inheritance. In general, for achieving a power estimate of 80%, the sample sizes needed for dizygotic and monozygotic twin cases were one half and one fourth of the sample size...

  5. Genetic susceptibility to bilateral tinnitus in a Swedish twin cohort

    DEFF Research Database (Denmark)

    Maas, Iris Lianne; Brüggemann, Petra; Requena, Teresa

    2017-01-01

    PURPOSE: Genetic contributions to tinnitus have been difficult to determine due to the heterogeneity of the condition and its broad etiology. Here, we evaluated the genetic and nongenetic influences on self-reported tinnitus from the Swedish Twin Registry (STR). METHODS: Cross-sectional data from...... the STR was obtained. Casewise concordance rates (the risk of one twin being affected given that his/her twin partner has tinnitus) were compared for monozygotic (MZ) and dizygotic (DZ) twin pairs (N = 10,464 concordant and discordant twin pairs) and heritability coefficients (the proportion of the total...... variance attributable to genetic factors) were calculated using biometrical model fitting procedures. RESULTS: Stratification of tinnitus cases into subtypes according to laterality (unilateral versus bilateral) revealed that heritability of bilateral tinnitus was 0.56; however, it was 0.27 for unilateral...

  6. Donor catch-up growth after laser surgery for twin-twin transfusion syndrome.

    Science.gov (United States)

    Chmait, Ramen H; Chon, Andrew H; Schrager, Sheree M; Kontopoulos, Eftichia V; Quintero, Rubén A; Vanderbilt, Douglas L

    2015-12-01

    To assess fetal growth after laser surgery for TTTS at the time of prenatal diagnosis, birth, and at 2years of age. Growth data were collected from surviving children treated between 2007 and 2010 as part of a study to assess neurodevelopment at 24months (±6weeks) corrected age. Fetal weights were obtained via ultrasound using Hadlock's formula at the time of preoperative assessment for laser surgery. Birth weights were recorded by the staff at the delivering institutions. Weights at 2years corrected age were recorded at the time of neurodevelopmental testing. Weights were converted into percentiles according to standard growth curves. Growth restriction was defined as demise, intrauterine growth restriction, Quintero stage, and gestational age of surgery or delivery. 48.5% were donors. The median fetal, birth, and 2-year weights for all twins were 288g, 1.9kg, and 11.8kg, respectively, and the overall prevalence of growth restriction was 28%, 22%, and 3%, respectively. Growth restriction rates at prenatal diagnosis were 56% in donors vs. 2% in recipients (OR=64.3, p<0.001); at birth, 35% vs. 10% (OR=5.0, p<0.01); and at 2years, 6% vs. 0%. Donors showed significant gains in weight percentile (B=13.1, p<0.001) and a significant decrease in growth restriction rates over time (B=-1.6, p<0.001). Weight discordance between donor and recipient pairs also significantly decreased over time (linear F(1,42)=54.34, p<0.001). After laser surgery for TTTS, donor twins exhibit significant catch-up growth by two years of age. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Multicenter dizygotic twin cohort study confirms two linkage susceptibility loci for body mass index at 3q29 and 7q36 and identifies three further potential novel loci

    DEFF Research Database (Denmark)

    Kettunen, J; Perola, M; Martin, N G

    2009-01-01

    OBJECTIVE: To identify common loci and potential genetic variants affecting body mass index (BMI, kg m(-2)) in study populations originating from Europe. DESIGN: We combined genome-wide linkage scans of six cohorts from Australia, Denmark, Finland, the Netherlands, Sweden and the United Kingdom...... with an approximately 10-cM microsatellite marker map. Variance components linkage analysis was carried out with age, sex and country of origin as covariates. SUBJECTS: The GenomEUtwin consortium consists of twin cohorts from eight countries (Australia, Denmark, the Netherlands, Finland, Italy, Norway, Sweden...... and the United Kingdom) with a total data collection of more than 500,000 monozygotic and dizygotic (DZ) twin pairs. Variance due to early-life events and the environment is reduced within twin pairs, which makes DZ pairs highly valuable for linkage studies of complex traits. This study totaled 4401 European-originated...

  8. Environmental influence of problematic social relationships on adolescents' daily cortisol secretion: a monozygotic twin-difference study.

    Science.gov (United States)

    Brendgen, M; Ouellet-Morin, I; Lupien, S J; Vitaro, F; Dionne, G; Boivin, M

    2017-02-01

    This study investigated the potential environmental effects of peer victimization and the quality of relationships with parents and friends on diurnal cortisol secretion in mid-adolescence. This study used the monozygotic (MZ) twin-difference design to control for genetic effects and thus estimate the unique environmental influences on diurnal cortisol. Participants were 136 MZ twin pairs (74 female pairs) for whom cortisol was assessed four times per day over four collection days grouped in a 2-week period in grade 8 (mean age = 14.07 years). Participants also provided self-reports of peer victimization from grade 4 to grade 8 and of the relationship quality with the mother, father and best friend in grade 8. The expected pattern of diurnal cortisol secretion was observed, with high levels at awakening followed by an increase 30 min later and a progressive decrease subsequently. Controlling for a host of confounders, only within-twin pair differences in peer victimization and a problematic relationship with the mother were significantly linked to twin differences in diurnal cortisol secretion. Specifically, whereas a more problematic mother-child relationship was associated with morning cortisol secretion, peer victimization was linked to cortisol secretion later in the day (diurnal slope). Controlling for genetic influences and other confounders, stressful relationships with peers and the mother exert unique and time-specific environmental influences on the pattern of diurnal cortisol secretion in mid-adolescence.

  9. Pain in the lumbar, thoracic or cervical regions: do age and gender matter? A population-based study of 34,902 Danish twins 20-71 years of age

    DEFF Research Database (Denmark)

    Leboeuf-Yde, Charlotte; Nielsen, Jan; Kyvik, Kirsten O

    2009-01-01

    , aged 20 to 71 years, representative of the general Danish population. Identical questions on pain were asked for the lumbar, thoracic and cervical regions. RESULTS: Low back pain was most common, followed by neck pain with thoracic pain being least common. Pain for at least 30 days in the past year......BACKGROUND: It is unclear to what extent spinal pain varies between genders and in relation to age. It was the purpose of this study to describe the self-reported prevalence of 1) pain ever and pain in the past year in each of the three spinal regions, 2) the duration of such pain over the past...... year, 3) pain radiating from these areas, and 4) pain in one, two or three areas. In addition, 5) to investigate if spinal pain reporting is affected by gender and 6) to see if it increases gradually with increasing age. METHOD: A cross-sectional survey was conducted in 2002 on 34,902 twin individuals...

  10. Laying the ghost of twin paradox

    Directory of Open Access Journals (Sweden)

    Popović Marko

    2009-01-01

    Full Text Available Someone's true age is not written in his ID, but in his biomarkers. Aging process is not caused by time passing, but by thermodynamically laws. Entropy, extent of metabolic reaction, and temperature are Lorentz invariant, so these facts make twin paradox impossible because there is no way for one twin to age slower than the other even if the time in his frame is dilated. Entropy is the function of state, not time. So as much as standard thermodynamics concerns, the path between two points in space is equivalent to the path between two states. Whether the point B is reached by moving faster using the longer way (with time dilatation, or slower by using shortcut (without time dilatation, the state of the system after completing the road should be the same. This is supported by the fact that when two twins reach the same space-time point (point B in which the state parameters are the same. If we use entropy as an age parameter, then both twins have the same entropy value and are exactly the same biological age. Therefore, the twin paradox is a logical mistake based on wrong first premise. Bergson symmetry is not necessary any more to explain the impossibility of twin paradox.

  11. Craniofacial morphology in Chinese female twins: a semi-longitudinal cephalometric study.

    Science.gov (United States)

    Peng, Jing; Deng, Hui; Cao, CaiFang; Ishikawa, Masaaki

    2005-12-01

    It would be of benefit to have a better understanding of the relative effects of genetics and environmental factors on craniofacial parameters when undertaking orthodontic therapy and treatment planning. However, there is a lack of such information in pre-adolescents. The aim of this study was to verify the degree of genetic and environmental contribution to the growth of the facial skeleton in twins aged 6 to 12 years. The material comprised the lateral cephalograms of 89 pairs of female twins in Beijing, China, of whom 61 pairs were diagnosed by DNA analysis as monozygotic (MZ) and 28 pairs as dizygotic (DZ). Four main groups (with a starting age of 6, 7, 9 and 11 years) were studied in a semi-longitudinal manner, with a sub-group further investigated for 2-4 consecutive years. The total sample therefore consisted of 183 pairs (MZ 110, DZ 73) aged from 6 to 12 years. The depths of the cranial base, mid and lower face were measured, as well as anterior and posterior face height. A two-tailed t-test showed significant environmental effects on lower face depth (P < 0.01), whilst genetic effects on face height were also significant (P < 0.01). The results suggest that early orthodontic intervention would have a greater influence on the antero-posterior rather than on the vertical plane of growth.

  12. A national Swedish longitudinal twin-sibling study of criminal convictions from adolescence through early adulthood.

    Science.gov (United States)

    Kendler, Kenneth S; Lönn, Sara Larsson; Maes, Hermine H; Morris, Nancy A; Lichtenstein, Paul; Sundquist, Jan; Sundquist, Kristina

    2015-06-01

    Prior twin and adoption studies have demonstrated the importance of both genetic and shared environmental factors in the etiology of criminal behavior (CB). However, despite substantial interest in life-course theories of CB, few genetically informative studies have examined CB in a developmental context. In 69,767 male-male twin pairs and full-sibling pairs with ≤ 2 years' difference in age, born 1958-1976 and ascertained from the Swedish Twin and Population Registries, we obtained information on all criminal convictions from 1973 to 2011 from the Swedish Crime Register. We fitted a Cholesky structural model, using the OpenMx package, to CB in these pairs over three age periods: 15-19, 20-24, and 25-29. The Cholesky model had two main genetic factors. The first began at ages 15-19 and declined in importance over development. The second started at ages 20-24 and was stable over time. Only one major shared environmental factor was seen, beginning at ages 15-19. Heritability for CB declined from ages 15-29, as did shared environmental effects, although at a slower rate. Genetic risk factors for CB in males are developmentally dynamic, demonstrating both innovation and attenuation. These results are consistent with theories of adolescent-limited and life-course persistent CB subtypes. Heritability for CB did not increase over time as might be predicted from active gene-environmental correlation. However, consistent with expectation, the proportion of variability explained by shared environmental effects declined slightly as individuals aged and moved away from their original homes and neighborhoods.

  13. Effect of birth order on neonatal morbidity and mortality among very low birthweight twins: a population based study

    Science.gov (United States)

    Shinwell, E; Blickstein, I; Lusky, A; Reichman, B

    2004-01-01

    Objective: To study the effect of birth order on the risk for respiratory distress syndrome (RDS), chronic lung disease (CLD), adverse neurological findings, and death in very low birthweight (VLBW; < 1500 g) twins. Methods: A population based study of VLBW infants from the Israel National VLBW Infant Database. The sample included all complete sets of VLBW twin pairs admitted to all 28 neonatal intensive care units between 1995 and 1999. Outcome variables were compared by birth order and stratified by mode of delivery and gestational age, using General Estimating Equation models, with results expressed as odds ratio (OR) with 95% confidence interval (CI). Results: Second twins were at increased risk for RDS (OR 1.51, 95% CI 1.29 to 1.76), CLD (OR 1.36, 95% CI 1.11 to 1.66), and death (OR 1.24, 95% CI 1.02 to 1.51) but not for adverse neurological findings (OR 1.20, 95% CI 0.91 to 1.60). Mode of delivery did not significantly influence outcome. The odds ratio for RDS in the second twin was inversely related to gestational age, and the increased risk for RDS and CLD was found in both vaginal and caesarean deliveries. Conclusions: VLBW second twins are at increased risk for acute and chronic lung disease and neonatal mortality, irrespective of mode of delivery. PMID:14977899

  14. Association between the birth of twins and parental divorce.

    Science.gov (United States)

    Jena, Anupam B; Goldman, Dana P; Joyce, Geoffrey

    2011-04-01

    Mothers of multiple births face higher rates of postpartum depression, yet evidence on the marital consequences of multiple births is limited. We examined the association between twin births and parental divorce. We used the 1980 U.S. Census to identify a large sample of mothers with and without twin births. The goal was to estimate multivariate logistic models of the association between birth of twins and divorce adjusting for race, age at marriage and first birth, and college education. We examined whether the association was affected by maternal education, age and sex composition of twins, and family size. Twins at first birth were associated with greater parental divorce compared with singletons (odds ratio, 1.08; 95% confidence interval, 1.01-1.16; absolute risk 13.7% with twins compared with 12.7%; P=.02). The association was statistically greater among mothers not attending college (14.9% with twins compared with 13.3%; P=.01) compared with those with some college (10.4% with twins compared with 10.5%; P=.34); those with children older than 8 years (15.6% with twins compared with 13.5%; P<.01) compared with younger children (10.6% with twins compared with 10.8%; P=.42); and those with at least one twin girl (13.8% with twins compared with 12.6%; P=.03) compared with twin boys (12.1% with twins compared with 12.5%, P=.38). Mothers with four or more children had a larger association between birth of twins and divorce (15.4% for mothers with twins at fourth birth compared with 11.3% for all other mothers with four or more children; P<.01) compared with mothers with twins at first birth (13.7% for twins at first birth compared with 12.7%; P=.02). Health consequences of twin births for children and mothers are well known. Twin births may be associated with longer-term parental divorce. Specific groups, namely mothers not completing college and mothers who already have more children, may be at higher risk. II.

  15. Twin specific risk factors in primary school achievements.

    Science.gov (United States)

    de Zeeuw, Eveline L; van Beijsterveldt, Catherina E M; de Geus, Eco J C; Boomsma, Dorret I

    2012-02-01

    The main aim of this study was to examine twin specific risk factors that influence educational achievement in primary school. We included prenatal factors that are not unique to twins, except for zygosity, but show a higher prevalence in twins than in singletons. In addition, educational achievement was compared between twins and their nontwin siblings in a within-family design. Data were obtained from parents and teachers of approximately 10,000 twins and their nontwin siblings registered with the Netherlands Twin Register. Teachers rated the proficiency of the children on arithmetic, language, reading, and physical education, and reported a national educational achievement test score (CITO). Structural equation modeling showed that gestational age, birth weight, and sex were significant predictors of educational achievement, even after correction for socioeconomic status. Mode of delivery and zygosity did not have an effect, while parental age only influenced arithmetic. Mode of conception, incubator time, and birth complications negatively affected achievement in physical education. The comparison of educational achievement of twins and singletons showed significantly lower ratings on arithmetic, reading, and language in twins, compared to their older siblings, but not compared to their younger siblings. Low gestational age and low birth weight were the most important risk factors for lower educational achievement of twins in primary school. It seems that the differences observed between twins and their nontwin siblings in educational achievement can largely be explained by birth order within the family.

  16. [Intrapair comparisons of diet and food preference in adult twins].

    Science.gov (United States)

    Kato, Kenji; Hayakawa, Kazuo; Onoi, Miyuki; Shimizu, Tadahiko; Yura, Akiko; Yokoyama, Yoshie; Kanamori, Masao

    2002-12-01

    An investigation was conducted on the influence of genetic and lifestyle factors related to the determination of eating behavior of human beings. The objective was to obtain information about lifestyle factors that may help health professionals intervene in terms of the prevention of diet-related diseases. The subjects were 180 pairs of adult twins aged over thirty, comprising of 134 monozygotic (MZ) and 46 dizygotic (DZ) pairs. Every subject was given an interview concerning dietary habits, food preference, food intake, as a part of medical examination. The intake of food containing salt and fat, the intake of food meals, the frequency of daily meals, and the frequency of eating 18 sorts of food were assessed on an individual basis, with a questionnaire on nutrition. The expected and observed values of intrapair concordance rates were calculated, and compared within each zygosity, using the chi-square test. Significant differences between the expected and observed for intrapair concordance rates were shown with monozygotic twins, regarding every category of question. Comparing MZ pairs who had lived apart before their twenties with the other MZ pairs, the latter had a tendency to show significant differences between the expected and observed values of intrapair concordance rate, regarding every category of question. In each case, the observed values were higher than the expected values. The study implied that both genetic and lifestyle factors influence the determinants of eating behavior of human beings. This finding shows the importance of understanding individual characteristics of food preference and eating behavior for intervention regarding lifestyle factors for prevention of diet-related diseases.

  17. A study of diabetes mellitus within a large sample of Australian twins

    DEFF Research Database (Denmark)

    Condon, Julianne; Shaw, Joanne E; Luciano, Michelle

    2008-01-01

    with type 2 diabetes (T2D), 41 female pairs with gestational diabetes (GD), 5 pairs with impaired glucose tolerance (IGT) and one pair with MODY. Heritabilities of T1D, T2D and GD were all high, but our samples did not have the power to detect effects of shared environment unless they were very large......Twin studies of diabetes mellitus can help elucidate genetic and environmental factors in etiology and can provide valuable biological samples for testing functional hypotheses, for example using expression and methylation studies of discordant pairs. We searched the volunteer Australian Twin...... Registry (19,387 pairs) for twins with diabetes using disease checklists from nine different surveys conducted from 1980-2000. After follow-up questionnaires to the twins and their doctors to confirm diagnoses, we eventually identified 46 pairs where one or both had type 1 diabetes (T1D), 113 pairs...

  18. Genetic and environmental contributions to pro-social attitudes: a twin study of social responsibility.

    Science.gov (United States)

    Rushton, J Philippe

    2004-12-22

    Although 51 twin and adoption studies have been performed on the genetic architecture of antisocial behaviour, only four previous studies have examined a genetic contribution to pro-social behaviour. Earlier work by the author with the University of London Institute of Psychiatry Adult Twin Register found that genes contributed approximately half of the variance to measures of self-report altruism, empathy, nurturance and aggression, including acts of violence. The present study extends those results by using a 22-item Social Responsibility Questionnaire with 174 pairs of monozygotic twins and 148 pairs of dizygotic twins. Forty-two per cent of the reliable variance was due to the twins' genes, 23% to the twins' common environment and the remainder to the twins' non-shared environment.

  19. Global transcript profiles of fat in monozygotic twins discordant for BMI: pathways behind acquired obesity.

    Directory of Open Access Journals (Sweden)

    Kirsi H Pietiläinen

    2008-03-01

    Full Text Available The acquired component of complex traits is difficult to dissect in humans. Obesity represents such a trait, in which the metabolic and molecular consequences emerge from complex interactions of genes and environment. With the substantial morbidity associated with obesity, a deeper understanding of the concurrent metabolic changes is of considerable importance. The goal of this study was to investigate this important acquired component and expose obesity-induced changes in biological pathways in an identical genetic background.We used a special study design of "clonal controls," rare monozygotic twins discordant for obesity identified through a national registry of 2,453 young, healthy twin pairs. A total of 14 pairs were studied (eight male, six female; white, with a mean +/- standard deviation (SD age 25.8 +/- 1.4 y and a body mass index (BMI difference 5.2 +/- 1.8 kg/m(2. Sequence analyses of mitochondrial DNA (mtDNA in subcutaneous fat and peripheral leukocytes revealed no aberrant heteroplasmy between the co-twins. However, mtDNA copy number was reduced by 47% in the obese co-twin's fat. In addition, novel pathway analyses of the adipose tissue transcription profiles exposed significant down-regulation of mitochondrial branched-chain amino acid (BCAA catabolism (p < 0.0001. In line with this finding, serum levels of insulin secretion-enhancing BCAAs were increased in obese male co-twins (9% increase, p = 0.025. Lending clinical relevance to the findings, in both sexes the observed aberrations in mitochondrial amino acid metabolism pathways in fat correlated closely with liver fat accumulation, insulin resistance, and hyperinsulinemia, early aberrations of acquired obesity in these healthy young adults.Our findings emphasize a substantial role of mitochondrial energy- and amino acid metabolism in obesity and development of insulin resistance.

  20. Distribution, nesting activities, and age-class of territorial pairs of golden eagles at the Altamont Pass Wind Resource Area, California, 2014–16

    Science.gov (United States)

    Kolar, Patrick S.; Wiens, J. David

    2017-03-22

    The substantial numbers of golden eagles (Aquila chrysaetos) killed by collisions with oldgeneration wind turbines each year at the Altamont Pass Wind Resource Area (APWRA) in California has been well documented from previous studies. Few eagle nests have been documented in the APWRA, however, and adults and subadults 3+ years of age killed by turbines were generally not associated with nearby territories. We searched a subset of randomly selected survey plots for territorial pairs of golden eagles and associated nesting attempts within the APWRA as part of a broader investigation of population dynamics in the surrounding northern Diablo Range. In contrast to limited historical observations from 1988 to 2013, our surveys documented up to 15 territorial pairs within 3.2 kilometers (km) of wind turbines at the APWRA annually, 9 of which were not previously documented or only observed intermittently during historical surveys. We found evidence of nesting activity by adult pairs at least once during our study at six of these territories. We also determined that 23–36 percent of territories identified within 3.2 km of the APWRA had a subadult pair member, but that no pairs with a subadult member attempted to nest. These data will be useful to developers, wildlife managers, and future raptor studies in the area to evaluate and minimize the potential effects of wind energy or other development activities on previously unknown territorial pairs in the area.

  1. Comparison of academic performance of twins and singletons in adolescence

    DEFF Research Database (Denmark)

    Christensen, Kaare; Petersen, Inge; Skytthe, Axel

    2006-01-01

    deviations for twins and singletons (8.02 v 8.02 and 1.05 v 1.06) despite the twins weighing on average 908 g (95% confidence interval 886 to 930 g) less than the singletons at birth. Controlling for birth weight, gestational age at birth, age at test, and parents' age and education confirmed the similarity......OBJECTIVES: To determine whether twins in recent cohorts show similar academic performance in adolescence to singletons and to test the effect of birth weight on academic performance in twins and singletons. DESIGN: Follow-up study. SETTING: Denmark. PARTICIPANTS: All twins (n=3411) and a 5% random...... sample of singletons (n=7796) born in Denmark during 1986-8. MAIN OUTCOME MEASURES: Test scores in ninth grade (age 15 or 16), birth weight, gestational age at birth, parents' age, and parents' education. RESULTS: Ninth grade test scores were normally distributed, with almost identical mean and standard...

  2. The Brazilian Twin Registry.

    Science.gov (United States)

    Ferreira, Paulo H; Oliveira, Vinicius C; Junqueira, Daniela R; Cisneros, Lígia C; Ferreira, Lucas C; Murphy, Kate; Ordoñana, Juan R; Hopper, John L; Teixeira-Salmela, Luci F

    2016-12-01

    The Brazilian Twin Registry (BTR) was established in 2013 and has impelled twin research in South America. The main aim of the initiative was to create a resource that would be accessible to the Brazilian scientific community as well as international researchers interested in the investigation of the contribution of genetic and environmental factors in the development of common diseases, phenotypes, and human behavior traits. The BTR is a joint effort between academic and governmental institutions from Brazil and Australia. The collaboration includes the Federal University of Minas Gerais (UFMG) in Brazil, the University of Sydney and University of Melbourne in Australia, the Australian Twin Registry, as well as the research foundations CNPq and CAPES in Brazil. The BTR is a member of the International Network of Twin Registries. Recruitment strategies used to register twins have been through participation in a longitudinal study investigating genetic and environmental factors for low back pain occurrence, and from a variety of sources including media campaigns and social networking. Currently, 291 twins are registered in the BTR, with data on demographics, zygosity, anthropometrics, and health history having been collected from 151 twins using a standardized self-reported questionnaire. Future BTR plans include the registration of thousands of Brazilian twins identified from different sources and collaborate nationally and internationally with other research groups interested on twin studies.

  3. Outcomes of hip arthroscopy in patients aged 50 years or older compared with a matched-pair control of patients aged 30 years or younger.

    Science.gov (United States)

    Domb, Benjamin G; Linder, Dror; Finley, Zachary; Botser, Itamar B; Chen, Austin; Williamson, Joseph; Gupta, Asheesh

    2015-02-01

    Age has been suggested as a negative prognostic factor for hip arthroscopy. The purpose of this study was to compare patient characteristics and outcomes after hip arthroscopy in patients aged 50 years or older with a matched control group of patients aged 30 years or younger at a minimum postoperative follow-up of 2 years. Between September 2008 and March 2010, data were prospectively collected on all patients aged 50 years or older undergoing primary hip arthroscopy. Fifty-two patients met our inclusion and matching criteria, of whom all 52 (100%) were available for follow-up at a minimum of 2 years. This cohort was compared with a matched-pair control group of patients aged 30 years or younger who underwent similar procedures. The mean age of the study group was 54.8 years (range, 50 to 69 years), and that of the control group was 20.3 years (range, 13 to 30 years). The groups were matched at a 1:1 ratio, including 18 male patients (34.6%) and 34 female patients (65.4%) in each group, with a mean follow-up period of 32 months (range, 24 to 54 months). In the younger control group, the score improvement from preoperatively to 2 years' follow-up was 62.9 to 84.2 for the modified Harris Hip Score, 60.5 to 84.2 for the Non-Arthritic Hip Score, 63.1 to 86.5 for the Hip Outcome Score-Activities of Daily Living, and 42.2 to 72.7 for the Hip Outcome Score-Sport-Specific Subscale. In the older study group, the score improvement from preoperatively to 2 years' follow-up was 61.2 to 82.2 for the modified Harris Hip Score, 59.9 to 80.4 for the Non-Arthritic Hip Score, 63.9 to 83 for the Hip Outcome Score-Activities of Daily Living, and 41.2 to 64.6 for the Hip Outcome Score-Sport-Specific Subscale. All improvements in both groups were statistically significant at the 2-year postoperative follow-up (P arthroscopy should be considered a valid treatment option when treating hip pain in patients aged 50 years or older with a Tönnis arthritic grade of 0 or 1. Older patients

  4. Conjoined (Siamese) Twins in Zambia

    African Journals Online (AJOL)

    year-old Zambian multiparous mother gave birth to a set of twins with two heads ... (symmetric or mirror image) but one twin attached with an incomplete foetus is known as hetropagtrs. (asymmetrical). Thoracopagus twins (joined at the chest).

  5. Nineteen and Up study (19Up): understanding pathways to mental health disorders in young Australian twins.

    Science.gov (United States)

    Couvy-Duchesne, Baptiste; O'Callaghan, Victoria; Parker, Richard; Mills, Natalie; Kirk, Katherine M; Scott, Jan; Vinkhuyzen, Anna; Hermens, Daniel F; Lind, Penelope A; Davenport, Tracey A; Burns, Jane M; Connell, Melissa; Zietsch, Brendan P; Scott, James; Wright, Margaret J; Medland, Sarah E; McGrath, John; Martin, Nicholas G; Hickie, Ian B; Gillespie, Nathan A

    2018-03-17

    The Nineteen and Up study (19Up) assessed a range of mental health and behavioural problems and associated risk factors in a genetically informative Australian cohort of young adult twins and their non-twin siblings. As such, 19Up enables detailed investigation of genetic and environmental pathways to mental illness and substance misuse within the Brisbane Longitudinal Twin Sample (BLTS). Twins and their non-twin siblings from Queensland, Australia; mostly from European ancestry. Data were collected between 2009 and 2016 on 2773 participants (age range 18-38, 57.8% female, 372 complete monozygotic pairs, 493 dizygotic pairs, 640 non-twin siblings, 403 singleton twins). A structured clinical assessment (Composite International Diagnostic Interview) was used to collect lifetime prevalence of diagnostic statistical manual (4th edition) (DSM-IV) diagnoses of major depressive disorder, (hypo)mania, social anxiety, cannabis use disorder, alcohol use disorder, panic disorder and psychotic symptoms. Here, we further describe the comorbidities and ages of onset for these mental disorders. Notably, two-thirds of the sample reported one or more lifetime mental disorder.In addition, the 19Up study assessed general health, drug use, work activity, education level, personality, migraine/headaches, suicidal thoughts, attention deficit hyperactivity disorder (ADHD) symptomatology, sleep-wake patterns, romantic preferences, friendships, familial environment, stress, anorexia and bulimia as well as baldness, acne, asthma, endometriosis, joint flexibility and internet use.The overlap with previous waves of the BLTS means that 84% of the 19Up participants are genotyped, 36% imaged using multimodal MRI and most have been assessed for psychological symptoms at up to four time points. Furthermore, IQ is available for 57%, parental report of ADHD symptomatology for 100% and electroencephalography for 30%. The 19Up study complements a phenotypically rich, longitudinal collection of

  6. Why do identical twins differ in personality: shared environment reconsidered.

    Science.gov (United States)

    Torgersen, Anne Mari; Janson, Harald

    2002-02-01

    While heritability studies show that most of the variance in adult personality can be attributed to genetic or so-called nonshared environmental influence, this does not mean that shared events lack importance for the development of later personality differences. We studied the relationship between Big Five personality differences in monozygotic (MZ) twins at age 29, and life stressors at age 6 to 15, using prospective data from 26 MZ pairs studied from birth onwards. A positive significant correlation was found between stressors in childhood and early adolescence, and intrapair personality differences in Agreeableness, Openness, Conscientiousness, and five-factor profiles. We note that the effects of shared events are labeled "nonshared" environment when the effect is to make siblings more different. Case examples illustrate the relationship between stress and personality differences, and provide hypotheses for further studies in larger samples.

  7. Gray and white matter volume abnormalities in monozygotic and same-gender dizygotic twins discordant for schizophrenia

    DEFF Research Database (Denmark)

    Hilshoff, Hilleke E.; Brans, Rachel G. H.; van Haren, Neeltje E. M.

    2004-01-01

    BACKGROUND: Whole brain tissue volume decreases in schizophrenia have been related to both genetic risk factors and disease-related (possibly nongenetic) factors; however, whether genetic and environmental risk factors in the brains of patients with schizophrenia are differentially reflected...... in gray or white matter volume change is not known. METHODS: Magnetic resonance imaging (1.5 T) brain scans of 11 monozygotic and 11 same-gender dizygotic twin pairs discordant for schizophrenia were acquired and compared with 11 monozygotic and 11 same-gender dizygotic healthy control twin pairs. RESULTS......: Repeated-measures volume analysis of covariance revealed decreased whole brain volume in the patients with schizophrenia as compared with their co-twins and with healthy twin pairs. Decreased white matter volume was found in discordant twin pairs compared with healthy twin pairs, particularly...

  8. Upgrades for TwinSol facility

    Energy Technology Data Exchange (ETDEWEB)

    O’Malley, P.D.; Bardayan, D.W.; Kolata, J.J.; Hall, M.R.; Hall, O.; Allen, J. [Physics Department, University of Notre Dame, Notre Dame, IN 46556 (United States); Becchetti, F.D. [Physics Department, U. Michigan, Ann Arbor MI 48109 (United States)

    2016-06-01

    TwinSol, a pair of coupled, superconducting solenoids, was one of the first devices capable of producing beams of radioactive nuclei at energies near the Coulomb barrier. A primary beam from University of Notre Dame (UND) tandem accelerator is used to bombard a primary target producing a secondary beam in flight. TwinSol is used to gather, separate, and focus the recoils. Since it was commissioned at the UND in 1997, at least 58 publications have reported data from its use and there have been hundreds of collaborators from many different countries that use this device. Currently, plans are in place at the UND to provide several upgrades to TwinSol, including a multi-cell gas production target and the possible addition of a third solenoid. Upgrades currently in progress will be discussed along with future plans.

  9. Evidence of genetic susceptibility to infectious mononucleosis: a twin study.

    Science.gov (United States)

    Hwang, A E; Hamilton, A S; Cockburn, M G; Ambinder, R; Zadnick, J; Brown, E E; Mack, T M; Cozen, W

    2012-11-01

    Infectious mononucleosis is a clinical manifestation of primary Epstein-Barr virus infection. It is unknown whether genetic factors contribute to risk. To assess heritability, we compared disease concordance in monozygotic to dizygotic twin pairs from the population-based California Twin Program and assessed the risk to initially unaffected co-twins. One member of 611 and both members of 58 twin pairs reported a history of infectious mononucleosis. Pairwise concordance in monozygotic and dizygotic pairs was respectively 12·1% [standard error (s.e.)=1·9%] and 6·1% (s.e.=1·2%). The relative risk (hazard ratio) of monozygotic compared to dizygotic unaffected co-twins of cases was 1·9 [95% confidence interval (CI) 1·1-3·4, P=0·03], over the follow-up period. When the analysis was restricted to same-sex twin pairs, that estimate was 2·5 (95% CI 1·2-5·3, P=0·02). The results are compatible with a heritable contribution to the risk of infectious mononucleosis.

  10. Attention problems and Attention-Deficit/Hyperactivity Disorder in discordant and concordant monozygotic twins: Evidence of environmental mediators.

    NARCIS (Netherlands)

    Lehn, H.; Derks, E.M.; Hudziak, J.; Heutink, P.; van Beijsterveldt, C.E.M.; Boomsma, D.I.

    2007-01-01

    OBJECTIVE: To study familial and nonfamilial environmental influences on attention problems and attention-deficit/hyperactivity disorder (ADHD) in monozygotic twins discordant and concordant-high and low for these traits. METHOD: Ninety-five twin pairs from The Netherlands Twin Register were

  11. Genetic and Environmental Influences on Correlations Between Hearing and Cognitive Functions in Middle and Older Chinese Twins

    DEFF Research Database (Denmark)

    Xu, Chunsheng; Zhang, Dongfeng; Tian, Xiaocao

    2017-01-01

    , including 0.5 kHz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 12.5 kHz, with the lower hearing thresholds indicating better hearing function. Cognitive and hearing functions were measured on 379 complete twin pairs (240 monozygotic and 139 dizygotic pairs) with a median age of 50 years (range: 40-80 years). Bivariate...... twin models were fitted to quantify the genetic and environmental components of the correlations between hearing and cognitive functions. The analysis showed significantly high genetic correlation between 2 kHz of hearing and cognition (r G = -1.00, 95% CI [-1.00, -0.46]) and moderate genetic...

  12. Measuring adolescents’ exposure to victimization: The Environmental Risk (E-Risk) Longitudinal Twin Study

    Science.gov (United States)

    Fisher, Helen L.; Caspi, Avshalom; Moffitt, Terrie E.; Wertz, Jasmin; Gray, Rebecca; Newbury, Joanne; Ambler, Antony; Zavos, Helena; Danese, Andrea; Mill, Jonathan; Odgers, Candice L.; Pariante, Carmine; Wong, Chloe C.; Arseneault, Louise

    2016-01-01

    This paper presents mutlilevel findings on adolescents’ victimization exposure from a large longitudinal cohort of twins. Data were obtained from the Environmental Risk (E-Risk) Longitudinal Twin Study, an epidemiological study of 2,232 children (1,116 twin pairs) followed to 18 years of age (with 93% retention). To assess adolescent victimization we combined best practices in survey research on victimization with optimal approaches to measuring life stress and traumatic experiences, and introduce a reliable system for coding severe victimization. One in three children experienced at least one type of severe victimization during adolescence (crime victimization, peer/sibling victimization, internet/mobile phone victimization, sexual victimization, family violence, maltreatment, or neglect), and most types of victimization were more prevalent amongst children from low socioeconomic backgrounds. Exposure to multiple victimization types was common, as was re-victimization; over half of those physically maltreated in childhood were also exposed to severe physical violence in adolescence. Biometric twin analyses revealed that environmental factors had the greatest influence on most types of victimization, while severe physical maltreatment from caregivers during adolescence was predominantly influenced by heritable factors. The findings from this study showcase how distinct levels of victimization measurement can be harmonized in large-scale studies of health and development. PMID:26535933

  13. Characterizing Blood Metabolomics Profiles Associated with Self-Reported Food Intakes in Female Twins.

    Science.gov (United States)

    Pallister, Tess; Jennings, Amy; Mohney, Robert P; Yarand, Darioush; Mangino, Massimo; Cassidy, Aedin; MacGregor, Alexander; Spector, Tim D; Menni, Cristina

    2016-01-01

    Using dietary biomarkers in nutritional epidemiological studies may better capture exposure and improve the level at which diet-disease associations can be established and explored. Here, we aimed to identify and evaluate reproducibility of novel biomarkers of reported habitual food intake using targeted and non-targeted metabolomic blood profiling in a large twin cohort. Reported intakes of 71 food groups, determined by FFQ, were assessed against 601 fasting blood metabolites in over 3500 adult female twins from the TwinsUK cohort. For each metabolite, linear regression analysis was undertaken in the discovery group (excluding MZ twin pairs discordant [≥1 SD apart] for food group intake) with each food group as a predictor adjusting for age, batch effects, BMI, family relatedness and multiple testing (1.17x10-6 = 0.05/[71 food groups x 601 detected metabolites]). Significant results were then replicated (non-targeted: Pfood groups (Pfood intake for potential use in nutritional epidemiological studies. We compiled our findings into the DietMetab database (http://www.twinsuk.ac.uk/dietmetab-data/), an online tool to investigate our top associations.

  14. Monozygotic twinning after in vitro fertilization/intracytoplasmic sperm injection treatment is not related to advanced maternal age, intracytoplasmic sperm injection, assisted hatching, or blastocyst transfer

    Directory of Open Access Journals (Sweden)

    Dennis Wu

    2014-09-01

    Conclusion: Until definite conclusions are drawn from larger trials, patients receiving IVF should not be overly concerned about the increase in MZT risk when proceeding to various assisted reproductive procedures (i.e., ICSI, AH, and blastocyst transfer. However, there is some evidence that the incidence of monochorionic–monoamniotic twins may be significantly increased after IVF/ICSI cycles. Patients should be informed about the possible obstetric complications regarding this rare type of MZT.

  15. Socialization and Selection Effects in the Association between Weight Conscious Peer Groups and Thin-Ideal Internalization: A Co-Twin Control Study

    Science.gov (United States)

    Burt, S. Alexandra; O’Connor, Shannon; Thompson, J. Kevin; Klump, Kelly L.

    2016-01-01

    Affiliation with weight conscious peer groups is theorized to increase thin-ideal internalization through socialization processes. However, selection effects could contribute if genetic and/or environmental predispositions lead to affiliation with weight conscious peers. Co-twin control methodology was used to examine socialization and selection effects in 614 female twins (ages 8–15) from the Michigan State University Twin Registry (MSUTR). Thin-ideal internalization and peer group characteristics were assessed via self-report questionnaires. Results suggested the presence of both socialization and selection effects. In terms of socialization, twins who reported increased exposure to weight conscious peers relative to their co-twins had elevated thin-ideal internalization scores, regardless of zygosity. However, associations between weight conscious peers and thin-ideal internationalization within twin pairs were attenuated, suggesting that genetic and shared environmental selection effects also contribute. Findings significantly extend previous work by confirming the presence of socialization processes and highlighting selection processes to be examined in future longitudinal research. PMID:26859605

  16. Twin anemia polycythemia sequence

    NARCIS (Netherlands)

    Slaghekke, Femke

    2014-01-01

    In this thesis we describe that Twin Anemia Polycythemia Sequence (TAPS) is a form of chronic feto-fetal transfusion in monochorionic (identical) twins based on a small amount of blood transfusion through very small anastomoses. For the antenatal diagnosis of TAPS, Middle Cerebral Artery – Peak

  17. The Project TALENT Twin and Sibling Study.

    Science.gov (United States)

    Prescott, Carol A; Achorn, Deanna Lyter; Kaiser, Ashley; Mitchell, Lindsey; McArdle, John J; Lapham, Susan J

    2013-02-01

    Project TALENT is a US national longitudinal study of about 377,000 individuals born in 1942-1946, first assessed in 1960. Students in about 1,200 schools participated in a 2-day battery covering aptitudes, abilities, interests, and individual and family characteristics (Flanagan, 1962; www.projectTALENT.org). Follow-up assessments 1, 5, and 11 years later assessed educational and occupational outcomes. The sample includes approximately 92,000 siblings from 40,000 families, including 2,500 twin pairs and 1,200 other siblings of twins. Until recently, almost no behavior genetic research has been conducted with the sample. In the original data collection information was not collected with the intent to link family members. Recently, we developed algorithms using names, addresses, birthdates, and information about family structure to link siblings and identify twins. We are testing several methods to determine zygosity, including use of yearbook photographs. In this paper, we summarize the design and measures in Project TALENT, describe the Twin and Sibling sample, and present our twin-sib-classmate model. In most twin and family designs, the 'shared environment' includes factors specific to the family combined with between-family differences associated with macro-level variables such as socioeconomic status. The school-based sampling design used in Project TALENT provides a unique opportunity to partition the shared environment into variation shared by siblings, specific to twins, and associated with school- and community-level factors. The availability of many measured characteristics on the family, schools, and neighborhoods enhances the ability to study the impact of specific factors on behavioral variation.

  18. Heredity In Sarcoidosis - A Registry-Based Twin Study

    DEFF Research Database (Denmark)

    Sverrild, Asger; Backer, Vibeke; Kyvik, Kirsten Ohm

    2008-01-01

    BACKGROUND: Sarcoidosis is a multiorgan, granulomatous, inflammatory disease with unknown aetiology. Familial clustering of cases and ethnic variation in the epidemiology suggests a genetic influence on the disease susceptibility. AIM: This paper reports twin concordance and heritability estimates...... of sarcoidosis in order to assess the overall contribution of genetic factors to the disease susceptibility. METHODS: Monozygotic and dizygotic twins enrolled in either the Danish or the Finnish population-based, national Twin Cohorts (61,662 pairs in total) were linked to diagnostic information on sarcoidosis.......012. Compared to the general population we found an 80-fold increased risk of developing sarcoidosis in co-twins of affected monozygotic brothers or sisters. The increased risk in dizygotic twins was on the other hand only 7-fold. Aetiological model fitting gave a heritability of sarcoidosis of 0.66 (95% CI 0...

  19. Twinning in muskox and the cytogenetic investigation of a freemartin

    Directory of Open Access Journals (Sweden)

    N. J. Reindl

    1993-12-01

    Full Text Available The occurrence of twinning has been documented for muskox in both wild and captive populations. Of two known captive twin births only one set survived beyond 120 days. In both cases the twins were male-female pairs and both females showed abnormal sexual development. Two sets of stillborn twins have also been recorded. All four stillborn fetuses were female and none showed anomalies of the reproductive tract upon post-mortem examination. Blood cultures from the surviving male and female twins revealed that both were chimeric, indicating the admixture of fetal blood. Fibroblast cultures were normal for the respective sex of each individual. The freemartin heifer had anatomical abnormalities of the clitoris as well as the secondary sex characteristics of a male.

  20. Quantitative ultrasound of the hand phalanges in a cohort of monozygotic twins: influence of genetic and environmental factors

    Energy Technology Data Exchange (ETDEWEB)

    Guglielmi, G. [Scientific Institute Hospital, Department of Radiology, San Giovanni Rotondo (Italy); Terlizzi, F. de [IGEA Biophysics Lab, Carpi (Italy); Torrente, I.; Mingarelli, R. [Mendel Institute, Rome (Italy); Dallapiccola, B. [Scientific Institute Hospital, Department of Radiology, San Giovanni Rotondo (Italy); Mendel Institute, Rome (Italy)

    2005-11-01

    Our objective was to evaluate the similarities and differences in bone mass and structure between pairs of monozygotic twins as measured by means of the quantitative ultrasound (QUS) technique. A cohort of monozygotic twins was measured by QUS of the hand phalanges using the DBM sonic bone profiler (IGEA, Carpi, Italy). The parameters studied were amplitude-dependent speed of sound (AD-SoS), ultrasound bone profile index (UBPI), signal dynamics (SDy) and bone transmission time (BTT). Linear correlation coefficients, multivariate linear analysis and the ANOVA test were used to assess intrapair associations between variables and to determine which factors influence the intrapair differences in QUS variables. One hundred and six pairs of monozygotic twins were enrolled in the study, 68 females and 38 males in the age range 5 to 71 years. Significant intrapair correlations were obtained in the whole population and separately for males and females, regarding height (r =0.98-0.99, p <0.0001), weight (r =0.95-0.96, p <0.0001), AD-SoS (r =0.90-0.92, p <0.0001), BTT (r =0.94-0.95, p <0.0001) and other QUS parameters (r >0.74, p <0.0001). Multivariate analysis revealed that intrapair differences between AD-SoS, SDy, UBPI and BTT are significantly influenced by age in the whole population and in the female population. Furthermore, the ANOVA test showed, for the female group, a significant increase in the intrapair differences in SDy and UBPI above 40 years. A relative contribution of genetic factors to skeletal status could be observed by phalangeal QUS measurement in monozygotic twins. A significant increase in the intrapair difference in QUS parameters with increasing age and onset of menopause also suggests the importance of environmental factors in the female twin population. (orig.)

  1. Characterization of Gastric Microbiota in Twins.

    Science.gov (United States)

    Dong, Quanjiang; Xin, Yongning; Wang, Lili; Meng, Xinying; Yu, Xinjuan; Lu, Linlin; Xuan, Shiying

    2017-02-01

    Contribution of host genetic backgrounds in the development of gastric microbiota has not been clearly defined. This study was aimed to characterize the biodiversity, structure and composition of gastric microbiota among twins. A total of four pairs of twins and eight unrelated individuals were enrolled in the study. Antral biopsies were obtained during endoscopy. The bacterial 16S rRNA gene was amplified and pyrosequenced. Sequences were analyzed for the composition, structure, and α and β diversities of gastric microbiota. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Fusobacteria were the most predominant phyla of gastric microbiota. Each individual, twins as well as unrelated individuals, harbored a microbiota of distinct composition. There was no evidence of additional similarity in the richness and evenness of gastric microbiota among co-twins as compared to unrelated individuals. Calculations of θ YC and PCoA demonstrated that the structure similarity of gastric microbial community between co-twins did not increase compared to unrelated individuals. In contrast, the structure of microbiota was altered enormously by Helicobacter pylori infection. These results suggest that host genetic backgrounds had little effect in shaping the gastric microbiota. This property of gastric microbiota could facilitate the studies discerning the role of microbiota from genetic grounds in the pathogenesis.

  2. Low twinning rate and seasonal effects on twinning in a fertile population, the Hutterites

    Science.gov (United States)

    Nonaka, K.; Miura, T.; Peter, K.

    1993-09-01

    This paper analyzes from the mid 18th century to 1987 the birth records of the “Dariusleut,” one of the three subgroups of the Hutterite population. The aim of this study is to describe several aspects of the twinning rate in a fertile population. The overall rate of twinning was 0.90%:103 twins among all 11492 maternities. The rate peaked at the 7th birth order and at the maternal age of 40 years and over. Until the mid 19th century when the Hutterites lived in Russia, the twinning rate was higher (1.5%), and it decreased during the migration period in the second half of the 19th century (0.7%). After the group had settled in the USA and Canada, the population maintained a twinning rate of 1.0% until 1965. After 1965 the rate decreased to 0.7%, partly due to a decline in fertility among women aged 30 years and over. There was a significant seasonal variation: the twinning rate decreased to 0.5% in May July compared to 1.2% for the other three seasons during the years up to 1965 ( P<0.01), while more recent mothers did not show such a seasonal variation. The incidence of twin births in this population seems to have been influenced by environmental factors, which would change their effect seasonally and secularly.

  3. [Twin pregnancy as the risk factor for neonatal intraventricular hemorrhage].

    Science.gov (United States)

    Wieczorek, Aleksandra I; Krasomski, Grzegorz

    2015-02-01

    The aim of this study was to find the perinatal risk factors of intravenricular hemorrhage in twin neonates. A retrospective analysis of 203 twin pregnancies and deliveries between 2003 and 2009 was performed. Then data according birth state and neonatal complications in 406 twins were analyzed. Twin outcome was compared with the outcome of 105 singletons born at the same time and at the same gestational age as twins. Intraventricular hemorrhage was diagnosed in 116/406 (29%) of twins. IVH was found two times more often in the analyzed group than in singletons born at the same gestational age (29% vs. 18%, p = 0,03). In 96% I and II grade hemorrhage was diagnosed and in 4% III and IV grade hemorrhage in the Papille scale was found. 1) Intraventricular hemorrhage is found more often in twins than in singleton neonates born at the same gestational age. 2) IVH in twins correlate with preterm birth and low birth weight. IVH occur more often in twins with birth weight discordance and with too small maternal weight gain.

  4. The etiology of behavioral problems and competencies in very young twins.

    Science.gov (United States)

    Saudino, Kimberly J; Carter, Alice S; Purper-Ouakil, Diane; Gorwood, Philip

    2008-02-01

    Although genetic and environmental influences on behavior problems in middle childhood and adolescence have been well-studied, little is known about the etiology of behavior problems in very early childhood. The present study explores genetic and environmental contributions to individual differences in behavior problems and competences in an infant-toddler sample of twins. There were 1,950 twin pairs (mean age=23.8 months) who were rated by parents on the Infant-Toddler Social and Emotional Assessment. All four domains (Externalizing, Internalizing, Dysregulation, Competence) and 20 subscales-indices on the Infant-Toddler Social and Emotional Assessment displayed significant heritability. There were also substantial shared environmental influences operating on most of the domains and subscales. Compared with behavior problems, behavioral competencies were less heritable and more influenced by shared environments. (c) 2008 APA, all rights reserved

  5. The contribution of diet and genotype to iron status in women: a classical twin study.

    Science.gov (United States)

    Fairweather-Tait, Susan J; Guile, Geoffrey R; Valdes, Ana M; Wawer, Anna A; Hurst, Rachel; Skinner, Jane; Macgregor, Alexander J

    2013-01-01

    This is the first published report examining the combined effect of diet and genotype on body iron content using a classical twin study design. The aim of this study was to determine the relative contribution of genetic and environmental factors in determining iron status. The population was comprised of 200 BMI- and age-matched pairs of MZ and DZ healthy twins, characterised for habitual diet and 15 iron-related candidate genetic markers. Variance components analysis demonstrated that the heritability of serum ferritin (SF) and soluble transferrin receptor was 44% and 54% respectively. Measured single nucleotide polymorphisms explained 5% and selected dietary factors 6% of the variance in iron status; there was a negative association between calcium intake and body iron (p = 0.02) and SF (p = 0.04).

  6. Leisure-time physical inactivity and association with body mass index: a Finnish Twin Study with a 35-year follow-up.

    Science.gov (United States)

    Piirtola, Maarit; Kaprio, Jaakko; Waller, Katja; Heikkilä, Kauko; Koskenvuo, Markku; Svedberg, Pia; Silventoinen, Karri; Kujala, Urho M; Ropponen, Annina

    2017-02-01

    We investigated the stability and change of leisure-time physical inactivity in adult men and women during a 35-year follow-up. We also analysed the impact of long-term physical inactivity on the development of body mass index (BMI). : In this population-based cohort study, 5254 Finnish twin individuals (59% women) participated in four surveys in 1975, 1981, 1990 and 2011. Mean age at baseline was 23.9 years. Individual long-term leisure-time physical activity (LTPA) was categorized into seven classes varying from 'persistently inactive' to 'persistently active'. We used the multivariate multilevel mixed-effects linear regression model and paired-sample t-test in the analyses. Co-twin control design was used for examining within-pair associations. : Of men 11%, and of women 8%, were persistently inactive. Among both sexes, the mean BMI slope trajectories were steeper among the persistently inactive and those who became inactive than among those who were persistently active. Overall, the inactive participants gained 1.4 kg/m 2 [95% confidence interval (CI) 1.2 to 1.7] more in weight than did the active participants from 1975 to 2011. Among twin pairs discordant for LTPA, the corresponding difference was 1.4 kg/m 2 (95% CI 0.83 to 2.0) in dizygotic pairs and 0.68 kg/m 2 (95% CI 0.05 to1.3) in monozygotic pairs. Over a 35-year time span from young adulthood, persistently inactive participants and those who had become inactive had greater weight increases than those who were persistently active. This association was also found in twin-pair analyses, although attenuated in monozygotic pairs. This may support the importance of LTPA in weight management, although further causal inference is required. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

  7. Continuity of Genetic and Environmental Influences on Cognition across the Life Span: A Meta-Analysis of Longitudinal Twin and Adoption Studies

    Science.gov (United States)

    Tucker-Drob, Elliot M.; Briley, Daniel A.

    2014-01-01

    The longitudinal rank-order stability of cognitive ability increases dramatically over the lifespan. Multiple theoretical perspectives have proposed that genetic and/or environmental mechanisms underlie the longitudinal stability of cognition, and developmental trends therein. However, the patterns of stability of genetic and environmental influences on cognition over the lifespan largely remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically-informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,538 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 non-adoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were low during early childhood, increased sharply over child development, and remained relatively high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and increased gradually to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment interaction and correlation. PMID:24611582

  8. Estimating heritability for cause specific mortality based on twin studies

    DEFF Research Database (Denmark)

    Scheike, Thomas; Holst, Klaus Kähler; von Bornemann Hjelmborg, Jacob

    2014-01-01

    the Danish twin registry and discuss how to define heritability for cancer occurrence. The key point is that this should be done taking censoring as well as competing risks due to e.g.  death into account. We describe the dependence between twins on the probability scale and show that various models can...... be used to achieve sensible estimates of the dependence within monozygotic and dizygotic twin pairs that may vary over time. These dependence measures can subsequently be decomposed into a genetic and environmental component using random effects models. We here present several novel models that in essence...

  9. Heritability of retinal vascular fractals: a twin study

    DEFF Research Database (Denmark)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line

    . The retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficents. Falconer´s formula and quantitative genetic models were used to determine the genetic component of variation. Results: The retinal...... 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, 54% of the variation was explained...

  10. Twin Pregnancy with Gastroschisis in Both Twins

    Directory of Open Access Journals (Sweden)

    Hui-Fen Kao

    2007-12-01

    Conclusion: The cause of gastroschisis is unknown, although possible exogenous causes have been studied. The diagnosis of gastroschisis in twin pregnancy is always in late gestation. Therefore, maternal serum alpha feto-protein screening and a detailed prenatal ultrasound evaluation are recommended in multifetal pregnancies.

  11. The Mid-Atlantic Twin Registry, revisited.

    Science.gov (United States)

    Lilley, Emily C H; Silberg, Judy L

    2013-02-01

    The Mid-Atlantic Twin Registry (MATR) is a population-based registry of more than 56,000 twins primarily born or living in Virginia, North Carolina, and South Carolina. The MATR employs several methods of ascertaining twins, and devotes considerable resources to tracking and maintaining communication with MATR participants. Researchers may utilize the MATR for administration of research services including study recruitment, collection of DNA, archival data set creation, as well as data collection through mailed, phone, or online surveys. In addition, the MATR houses the MATR Repository, with over 1,200 blood samples available for researchers interested in DNA genotyping. For over 35 years MATR twins have participated in research studies with investigators from diverse scientific disciplines and various institutions. These studies, which have resulted in numerous publications, have covered a range of topics, including the human microbiome, developmental psychopathology, depression, anxiety, substance use, epigenetics of aging, children of twins, pre-term birth, social attitudes, seizures, eating disorders, as well as sleep homeostasis. Researchers interested in utilizing twins are encouraged to contact the MATR to discuss potential research opportunities.

  12. Digital Twins in Health Care: Ethical Implications of an Emerging Engineering Paradigm.

    Science.gov (United States)

    Bruynseels, Koen; Santoni de Sio, Filippo; van den Hoven, Jeroen

    2018-01-01

    Personalized medicine uses fine grained information on individual persons, to pinpoint deviations from the normal. 'Digital Twins' in engineering provide a conceptual framework to analyze these emerging data-driven health care practices, as well as their conceptual and ethical implications for therapy, preventative care and human enhancement. Digital Twins stand for a specific engineering paradigm, where individual physical artifacts are paired with digital models that dynamically reflects the status of those artifacts. When applied to persons, Digital Twins are an emerging technology that builds on in silico representations of an individual that dynamically reflect molecular status, physiological status and life style over time. We use Digital Twins as the hypothesis that one would be in the possession of very detailed bio-physical and lifestyle information of a person over time. This perspective redefines the concept of 'normality' or 'health,' as a set of patterns that are regular for a particular individual , against the backdrop of patterns observed in the population. This perspective also will impact what is considered therapy and what is enhancement, as can be illustrated with the cases of the 'asymptomatic ill' and life extension via anti-aging medicine. These changes are the consequence of how meaning is derived, in case measurement data is available. Moral distinctions namely may be based on patterns found in these data and the meanings that are grafted on these patterns. Ethical and societal implications of Digital Twins are explored. Digital Twins imply a data-driven approach to health care. This approach has the potential to deliver significant societal benefits, and can function as a social equalizer, by allowing for effective equalizing enhancement interventions. It can as well though be a driver for inequality, given the fact that a Digital Twin might not be an accessible technology for everyone, and given the fact that patterns identified across a

  13. Does the sex of one’s co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts

    DEFF Research Database (Denmark)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero

    2017-01-01

    Background: The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and th...

  14. Does the sex of one's co-twin affect height and BMI in adulthood? : A study of dizygotic adult twins from 31 cohorts

    NARCIS (Netherlands)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero; Ahrenfeldt, Linda; Pietiläinen, Kirsi H; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Hur, Yoon-Mi; Jeong, Hoe-Uk; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Cutler, Tessa L; Kandler, Christian; Jang, Kerry L; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten Ohm; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Derom, Catherine A; Vlietinck, Robert F; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; Pang, Zengchang; Tan, Qihua; Zhang, Dongfeng; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Hjelmborg, Jacob V B; Rebato, Esther; Swan, Gary E; Krasnow, Ruth; Busjahn, Andreas; Lichtenstein, Paul; Öncel, Sevgi Y; Aliev, Fazil; Baker, Laura A; Tuvblad, Catherine; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Yokoyama, Yoshie; Hopper, John L; Loos, Ruth J F; Boomsma, Dorret I; Sørensen, Thorkild I A; Silventoinen, Karri; Kaprio, Jaakko; van Beijsterveldt, C.E.M.

    2017-01-01

    BACKGROUND: The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and the

  15. Increased risk of type 2 diabetes in elderly twins

    DEFF Research Database (Denmark)

    Poulsen, Pernille; Grunnet, Louise G; Pilgaard, Kasper

    2009-01-01

    OBJECTIVE: Genetic susceptibility, low birth weight (LBW), and aging are key etiological factors in the development of type 2 diabetes. LBW is common among twins. It is unknown whether twin status per se is associated with risk of type 2 diabetes, and valid concordance rates of type 2 diabetes...... in twins on a lifetime perspective are lacking. RESEARCH DESIGN AND METHODS: A clinical study was done on a population-based cohort of same-sex elderly monozygotic (MZ) and dizygotic (DZ) twins (n = 297) and singleton control subjects (C) (n = 71) including measures of anthropometry and glucose tolerance...

  16. Quality of life in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Vinberg, Maj; Bech, Per; Kyvik, Kirsten Ohm

    2007-01-01

    -Risk twins) and without (the control group/Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. The aim of the present study was to investigate the hypothesis that a genetic liability to affective disorder is associated with a lower perception of quality......BACKGROUND: The disability and hardship associated with affective disorder is shared by the family members of affective patients and might affect the family member's quality of life. METHOD: In a cross-sectional, high-risk, case-control study, monozygotic (MZ) and dizygotic (DZ) twins with (High...... of life. RESULTS: Univariate analyses showed that quality of life in all domains was impaired for the 121 High-Risk twins compared to the 84 Low-Risk twins. In multiple regression analyses, the differences remained significant after adjustment for sex, age, marital status and years of education. Adjusted...

  17. Quantitative XRD analysis of {110} twin density in biotic aragonites.

    Science.gov (United States)

    Suzuki, Michio; Kim, Hyejin; Mukai, Hiroki; Nagasawa, Hiromichi; Kogure, Toshihiro

    2012-12-01

    {110} Twin densities in biotic aragonite have been estimated quantitatively from the peak widths of specific reflections in powder X-ray diffraction (XRD) patterns, as well as direct confirmation of the twins using transmission electron microscopy (TEM). Influence of the twin density on the peak widths in the XRD pattern was simulated using DIFFaX program, regarding (110) twin as interstratification of two types of aragonite unit layers with mirrored relationship. The simulation suggested that the twin density can be estimated from the difference of the peak widths between 111 and 021, or between 221 and 211 reflections. Biotic aragonite in the crossed-lamellar microstructure (three species) and nacreous microstructure (four species) of molluscan shells, fish otoliths (two species), and a coral were investigated. The XRD analyses indicated that aragonite crystals in the crossed-lamellar microstructure of the three species contain high density of the twins, which is consistent with the TEM examination. On the other hand, aragonite in the nacre of the four species showed almost no difference of the peak widths between the paired reflections, indicating low twin densities. The results for the fish otoliths were varied between the species. Such variation of the twin density in biotic aragonites may reflect different schemes of crystal growth in biomineralization. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. SUSY meets her twin

    Energy Technology Data Exchange (ETDEWEB)

    Katz, Andrey [Theory Division, CERN,CH-1211 Geneva 23 (Switzerland); Département de Physique Théorique and Center for Astroparticle Physics (CAP),Université de Genève,24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Mariotti, Alberto [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel,and International Solvay Institutes,Pleinlaan 2, B-1050 Brussels (Belgium); Pokorski, Stefan [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw,ul. Pasteura 5, PL-02-093 Warsaw (Poland); Redigolo, Diego [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University,Tel-Aviv 69978 (Israel); Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Rehovot 7610001 (Israel); Ziegler, Robert [Institute for Theoretical Particle Physics (TTP), Karlsruhe Institute of Technology,Engesserstraße 7, D-76128 Karlsruhe (Germany)

    2017-01-31

    We investigate the general structure of mirror symmetry breaking in the Twin Higgs scenario. We show, using the IR effective theory, that a significant gain in fine tuning can be achieved if the symmetry is broken hardly. We emphasize that weakly coupled UV completions can naturally accommodate this scenario. We analyze SUSY UV completions and present a simple Twin SUSY model with a tuning of around 10% and colored superpartners as heavy as 2 TeV. The collider signatures of general Twin SUSY models are discussed with a focus on the extended Higgs sectors.

  19. Monozygotic twins discordant for attention-deficit/hyperactivity disorder: ascertainment and clinical characteristics.

    Science.gov (United States)

    Sharp, Wendy S; Gottesman, Rebecca F; Greenstein, Deanna K; Ebens, Christen L; Rapoport, Judith L; Castellanos, F Xavier

    2003-01-01

    Nongenetic factors and phenomenology of attention-deficit/hyperactivity disorder (ADHD) were examined in monozygotic (MZ) twin pairs discordant for ADHD. Recruitment included telephone screening (n = 297 pairs), behavioral ratings obtained from parents and teachers (n = 59 pairs), and, finally, in-person assessment (n = 25 pairs; structured classroom observation, diagnostic interview, psychoeducational evaluation, birth record review, establishment of monozygosity, and anatomic brain imaging). Affected twins were further contrasted with previously studied affected singletons. Of the 25 MZ twin pairs qualifying for in-person evaluation, only 10 proved discordant for ADHD. Affected twins were mostly comparable with affected singletons on clinical measures, although fathers' self-ratings of childhood ADHD status were significantly lower in twins than in singletons. Discordance for ADHD in MZ twins appears to be ascribable to greater environmental discordance and decreased familiality. Despite these differences, affected twins were phenotypically comparable with affected singletons. Thus MZ twins discordant for ADHD, while rare, can inform research on the etiology and pathophysiology of this disorder.

  20. Genetic influences on dietary variety - Results from a twin study

    NARCIS (Netherlands)

    Scheibehenne, Benjamin; Todd, Peter M.; van den Berg, Stéphanie Martine; Hatemi, Peter K.; Eaves, Lindon J.; Vogler, Christian

    2014-01-01

    The heritability of variety seeking in the food domain was estimated from a large sample (N = 5,543) of middle age to elderly monozygotic and dizygotic twins from the “Virginia 30,000” twin study. Different dietary variety scores were calculated based on a semi-quantitative food choice questionnaire

  1. Community structure of age-0 fishes in paired mainstem and created shallow-water habitats in the Lower Missouri River

    Science.gov (United States)

    Starks, Trevor A.; Long, James M.; Dzialowski, Andrew R.

    2016-01-01

    Anthropogenic alterations to aquatic ecosystems have greatly reduced and homogenized riverine habitat, especially those used by larval and juvenile fishes. Creation of shallow-water habitats is used as a restoration technique in response to altered conditions in several studies globally, but only recently in the USA. In the summer of 2012, the U.S. Army Corps of Engineers sampled larval and juvenile fishes at six paired sites (mainstem and constructed chute shallow-water habitats) along a section of the Missouri River between Rulo, NE and St. Louis, MO, USA. From those samples, we enumerated and identified a total of 7622 fishes representing 12 families. Community responses of fishes to created shallow-water habitats were assessed by comparisons of species richness and diversity measures between paired sites and among sampling events. Shannon entropy measures were transformed, and gamma diversity (total diversity) was partitioned into two components, alpha (within community) and beta (between community) diversity using a multiplicative decomposition method. Mantel test results suggest site location, time of sampling event and habitat type were drivers of larval and juvenile community structure. Paired t-test results indicated little to no differences in beta diversity between habitat types; however, chute habitats had significantly higher alpha and gamma diversity as well as increased abundances of Asian carp larvae when compared with mainstem shallow-water habitat. Our results not only show the importance of created shallow-water habitat in promoting stream fish diversity but also highlight the role space and time may play in future restoration and management efforts. 

  2. A prospective study of twinning and perinatal mortality in urban Guinea-Bissau

    Directory of Open Access Journals (Sweden)

    Bjerregaard-Andersen Morten

    2012-12-01

    Full Text Available Abstract Background Despite twinning being common in Africa, few prospective twin studies have been conducted. We studied twinning rate, perinatal mortality and the clinical characteristics of newborn twins in urban Guinea-Bissau. Methods The study was conducted at the Bandim Health Project (BHP, a health and demographic surveillance site in Bissau, the capital of Guinea-Bissau. The cohort included all newborn twins delivered at the National Hospital Simão Mendes and in the BHP study area during the period September 2009 to August 2011 as well as singleton controls from the BHP study area. Data regarding obstetric history and pregnancy were collected at the hospital. Live children were examined clinically. For a subset of twin pairs zygosity was established by using genetic markers. Results Out of the 5262 births from mothers included in the BHP study area, 94 were twin births, i.e. a community twinning rate of 18/1000. The monozygotic rate was 3.4/1000. Perinatal mortality among twins vs. singletons was 218/1000 vs. 80/1000 (RR = 2.71, 95% CI: 1.93-3.80. Among the 13783 hospital births 388 were twin births (28/1000. The hospital perinatal twin mortality was 237/1000. Birth weight  Conclusions Twins had a very high perinatal mortality, three-fold higher than singletons. A birth weight 

  3. Preparing for Twins

    Science.gov (United States)

    ... Ribbon Commands Skip to main content Turn off Animations Turn on Animations Our Sponsors Log in | Register Menu Log in | ... challenges with twins. He also can suggest helpful reading material or refer you to organizations that help ...

  4. Search for Genomic Alterations in Monozygotic Twins Discordant for Cleft Lip and/or Palate

    DEFF Research Database (Denmark)

    Kimani, Jane W; Yoshiura, Koh-Ichiro; Shi, Min

    2009-01-01

    consisting of 1,536 SNPs, to scan for genomic alterations in a sample of monozygotic twin pairs with discordant cleft lip and/or palate phenotypes. Paired analysis for deletions, amplifications and loss of heterozygosity, along with sequence verification of SNPs with discordant genotype calls did not reveal...... any genomic discordance between twin pairs in lymphocyte DNA samples. Our results demonstrate that postzygotic genomic alterations are not a common cause of monozygotic twin discordance for isolated cleft lip and/or palate. However, rare or balanced genomic alterations, tissue-specific events...

  5. Metabolic studies in unaffected co-twins of non-insulin-dependent diabetics.

    OpenAIRE

    Barnett, A H; Spiliopoulos, A J; Pyke, D A; Stubbs, W A; Burrin, J; Alberti, K G

    1981-01-01

    Forty-eight out of 53 non-insulin-dependent diabetic identical twin pairs were concordant for diabetes. In the five discordant pairs the diabetic twin had only recently been diagnosed. Oral glucose tolerance tests were carried out on the unaffected twins of the five pairs and on matched controls. Fasting concentrations of blood glucose (5.5 +/- 0.6 v 3.7 +/- 0.3 mmol/l; 99.1 +/- 10.8 v 66.6 +/- 5.4 mg/100 ml), haemoglobin A1 (mean 9.1%, range 8.8-9.2% v mean 7.9%, range 7.4-8.4%), lactate, al...

  6. Excess Mortality in Hyperthyroidism: The Influence of Preexisting Comorbidity and Genetic Confounding: A Danish Nationwide Register-Based Cohort Study of Twins and Singletons

    Science.gov (United States)

    Brandt, Frans; Almind, Dorthe; Christensen, Kaare; Green, Anders; Brix, Thomas Heiberg

    2012-01-01

    Context: Hyperthyroidism is associated with severe comorbidity, such as stroke, and seems to confer increased mortality. However, it is unknown whether this increased mortality is explained by hyperthyroidism per se, comorbidity, and/or genetic confounding. Objective: The objective of the study was to investigate whether hyperthyroidism is associated with an increased mortality and, if so, whether the association is influenced by comorbidity and/or genetic confounding. Methods: This was an observational cohort study using record-linkage data from nationwide Danish health registers. We identified 4850 singletons and 926 twins from same-sex pairs diagnosed with hyperthyroidism. Each case was matched with four controls for age and gender. The Charlson score was calculated from discharge diagnoses on an individual level to measure comorbidity. Cases and controls were followed up for a mean of 10 yr (range 0–31 yr), and the hazard ratio (HR) for mortality was calculated using Cox regression analyses. Results: In singletons there was a significantly higher mortality in individuals diagnosed with hyperthyroidism than in controls [HR 1.37; 95% confidence interval (CI) 1.30–1.46]. This persisted after adjustment for preexisting comorbidity (HR 1,28; 95% CI 1.21–1.36). In twin pairs discordant for hyperthyroidism (625 pairs), the twin with hyperthyroidism had an increased mortality compared with the corresponding cotwin (HR 1.43; 95% CI 1.09–1.88). However, this was found only in dizygotic pairs (HR 1.80; 95% CI 1.27–2.55) but not in monozygotic pairs (HR 0.95; 95% CI 0.60–1.50). Conclusions: Hyperthyroidism is associated with an increased mortality independent of preexisting comorbidity. The study of twin pairs discordant for hyperthyroidism suggests that genetic confounding influences the association between hyperthyroidism and mortality. PMID:22930783

  7. Creating a social world: a developmental twin study of peer-group deviance.

    Science.gov (United States)

    Kendler, Kenneth S; Jacobson, Kristen C; Gardner, Charles O; Gillespie, Nathan; Aggen, Steven A; Prescott, Carol A

    2007-08-01

    Peer-group deviance is strongly associated with externalizing behaviors. We have limited knowledge of the sources of individual differences in peer-group deviance. To clarify genetic and environmental contributions to peer-group deviance in twins from midchildhood through early adulthood. Retrospective assessments using a life-history calendar. Analysis by biometric growth curves. General community. Members of male-male pairs from the population-based Virginia Twin Registry personally interviewed in 1998-2004 (n = 1802). Self-reported peer-group deviance at ages 8 to 11, 12 to 14, 15 to 17, 18 to 21, and 22 to 25 years. Mean and variance of peer-group deviance increased substantially with age. Genetic effects on peer-group deviance showed a strong and steady increase over time. Family environment generally declined in importance over time. Individual-specific environmental influences on peer-group deviance levels were stable in the first 3 age periods and then increased as most twins left home. When standardized, the heritability of peer-group deviance is approximately 30% at ages 8 to 11 years and rises to approximately 50% across the last 3 time periods. Both genes and shared environment contributed to individual differences in the developmental trajectory of peer-group deviance. However, while the correlation between childhood peer-group deviance levels and the subsequent slope of peer-group deviance over time resulting from genetic factors was positive, the same relationship resulting from shared environmental factors was negative. As male twins mature and create their own social worlds, genetic factors play an increasingly important role in their choice of peers, while shared environment becomes less influential. The individual-specific environment increases in importance when individuals leave home. Individuals who have deviant peers in childhood, as a result of genetic vs shared environmental influences, have distinct developmental trajectories

  8. Twin probes for space geodesy

    International Nuclear Information System (INIS)

    Bertotti, B.

    1978-01-01

    The twin probe method, proposed by Bertotti and Colombo (1972) to get rid of nongravitational forces in interplanetary space, can be applied to a near-Earth orbit to eliminate the atmospheric drag. Two equal pairs of probes, each pair consisting of two passive, small and dense spheres of equal surface and different masses, are flown on a circular orbit at an altitude of about 300 km. Each pair determines the motion of an ideal point which feels only the gravitational forces. They are separated by a distance d of (100/200) km and are tracked from a spacecraft or the Space Shuttle, flying at the same altitude. The relative motion of the two ideal points is reconstructed and yields a measurement of the fine structure of the Earth gravitational field, corresponding to a harmonic order l approximately a/d (a is the radius of the Earth). The tracking can be done by laser ranging to the four spheres, covered by corner reflectors; Doppler ranging is more convenient for higher values of l and can also be used. The accuracy in the compensation of the non-gravitational forces and in the measurements one needs for a given l are discussed in detail. (author)

  9. A prospective study of twinning and perinatal mortality in urban Guinea-Bissau

    DEFF Research Database (Denmark)

    Bjerregaard-Andersen, Morten; Lund, Najaaraq; Jepsen, Frida Staarup

    2012-01-01

    ABSTRACT: BACKGROUND: Despite twinning being common in Africa, few prospective twin studies have been conducted. We studied twinning rate, perinatal mortality and the clinical characteristics of newborn twins in urban Guinea-Bissau. METHODS: The study was conducted at the Bandim Health Project (BHP......), a health and demographic surveillance site in Bissau, the capital of Guinea-Bissau. The cohort included all newborn twins delivered at the National Hospital Simao Mendes and in the BHP study area during the period September 2009 to August 2011 as well as singleton controls from the BHP study area. Data...... regarding obstetric history and pregnancy were collected at the hospital. Live children were examined clinically. For a subset of twin pairs zygosity was established by using genetic markers. RESULTS: Out of the 5262 births from mothers included in the BHP study area, 94 were twin births, i.e. a community...

  10. A TWIN STUDY OF SCHIZOAFFECTIVE-MANIA, SCHIZOAFFECTIVE-DEPRESSION AND OTHER PSYCHOTIC SYNDROMES

    OpenAIRE

    Cardno, Alastair G; Rijsdijk, Frühling V; West, Robert M; Gottesman, Irving I; Craddock, Nick; Murray, Robin M; McGuffin, Peter

    2011-01-01

    The nosological status of schizoaffective disorders remains controversial. Twin studies are potentially valuable for investigating relationships between schizoaffective-mania, schizoaffective-depression and other psychotic syndromes, but no such study has yet been reported. We ascertained 224 probandwise twin pairs (106 monozygotic, 118 same-sex dizygotic), where probands had psychotic or manic symptoms, from the Maudsley Twin Register in London (1948–1993). We investigated Research Diagnosti...

  11. Influence of intrauterine and extrauterine growth on neurodevelopmental outcome of monozygotic twins

    Directory of Open Access Journals (Sweden)

    R.K. Reolon

    2008-08-01

    Full Text Available There have been indications that intrauterine and early extrauterine growth can influence childhood mental and motor function. The objective of the present study was to evaluate the influence of intrauterine growth restriction and early extrauterine head growth on the neurodevelopmental outcome of monozygotic twins. Thirty-six monozygous twin pairs were evaluated at the corrected age of 12 to 42 months. Intrauterine growth restriction was quantified using the fetal growth ratio. The effects of birth weight ratio, head circumference at birth and current head circumference on mental and motor outcomes were estimated using mixed-effect linear regression models. Separate estimates of the between (interpair and within (intrapair effects of each measure on development were thus obtained. Neurodevelopment was assessed with the Bayley Scales of Infant Development, 2nd edition, by a psychologist blind to the exposure. A standardized neurological examination was performed by a neuropediatrician who was unaware of the exposures under investigation. After adjustment, birth weight ratio and head circumference at birth were not associated with motor or mental outcomes. Current head circumference was associated with mental but not with motor outcomes. Only the intrapair twin effect was significant. An increase of 1 cm in current head circumference of one twin compared with the other was associated with 3.2 points higher in Mental Developmental Index (95%CI = 1.06-5.32; P < 0.03. Thus, no effect of intrauterine growth was found on cognition and only postnatal head growth was associated with cognition. This effect was not shared by the co-twin.

  12. Reciprocal Longitudinal Associations Between Adolescent Twin Gambling and Delinquency.

    Science.gov (United States)

    Vitaro, Frank; C Hartl, Amy; Laursen, Brett; Brendgen, Mara; Dionne, Ginette; Boivin, Michel

    2015-12-01

    This study examined sibling influence over gambling involvement and delinquency in a sample of 628 twins (151 male dyads, 163 female dyads). Self-reports of gambling involvement and delinquency were collected for each twin at ages 13, 14 and 15 years. Results revealed evidence of between-twin influence. Higher levels of an adolescent's delinquency predicted an increase in his or her co-twin's delinquency from age 13 to age 14 and from age 14 to age 15. In contrast, gambling behavior was unaffected by the co-twin's gambling involvement. Within-twins, higher initial levels of delinquency predicted a subsequent increase in gambling behavior from age 13 to age 14 and again from age 14 to age 15, and higher initial levels of gambling involvement predicted an increase in delinquency from age 14 to age 15. Between and within siblings effects are discussed in light of the scant literature on (a) sibling influence on gambling, and (b) the links between gambling and delinquency.

  13. Natural history of disease in atomic bomb exposed twins in Hiroshima

    International Nuclear Information System (INIS)

    Satow, Yukio; Ohmae, Kiyokazu; Okamoto, Naomasa; Abe, Tsutomu; Watanabe, Shoji

    1982-01-01

    The subjects of this study are mainly pairs of monozygotic twins, one of whom was exposed to the atomic bomb and the other not exposed, and the natural history of the diseases of these twins was analyzed to find out genetic and environmental factors of the diseases and some biological effect of the atomic bomb exposure or other. In this study, 13 pairs of monozygotic and 5 pairs of dizygotic twins and other 34 cases of non-twins were examined by means of heart and lung X-ray films and electrocardiograms. The results suggest that most of the monozygotic twins show the similar findings of chest X-ray films, though their electrocardiograms have a tendency to deviate to the left in the QRS axis. These findings will not be enough to clear up the relation between the atomic bomb exposed and the abnormal electrocardiograms. (author)

  14. Multivariate genetic analysis of brain structure in an extended twin design

    DEFF Research Database (Denmark)

    Posthuma, D; de Geus, E.J.; Neale, M.C.

    2000-01-01

    quantitative scale and thus can be assessed in affected and unaffected individuals. Continuous measures increase the statistical power to detect genetic effects (Neale et al., 1994), and allow studies to be designed to collect data from informative subjects such as extreme concordant or discordant pairs....... Intermediate phenotypes for discrete traits, such as psychiatric disorders, can be neurotransmitter levels, brain function, or structure. In this paper we conduct a multivariate analysis of data from 111 twin pairs and 34 additional siblings on cerebellar volume, intracranial space, and body height....... The analysis is carried out on the raw data and specifies a model for the mean and the covariance structure. Results suggest that cerebellar volume and intracranial space vary with age and sex. Brain volumes tend to decrease slightly with age, and males generally have a larger brain volume than females...

  15. Migraine and risk of stroke: a national population-based twin study.

    Science.gov (United States)

    Lantz, Maria; Sieurin, Johanna; Sjölander, Arvid; Waldenlind, Elisabet; Sjöstrand, Christina; Wirdefeldt, Karin

    2017-10-01

    Numerous studies have indicated an increased risk for stroke in patients with migraine, especially migraine with aura; however, many studies used self-reported migraine and only a few controlled for familial factors. We aimed to investigate migraine as a risk factor for stroke in a Swedish population-based twin cohort, and whether familial factors contribute to an increased risk. The study population included twins without prior cerebrovascular disease who answered a headache questionnaire during 1998 and 2002 for twins born 1935-58 and during 2005-06 for twins born between 1959 and 1985. Migraine with and without aura and probable migraine was defined by an algorithm mapping on to clinical diagnostic criteria according to the International Classification of Headache Disorders. Stroke diagnoses were obtained from the national patient and cause of death registers. Twins were followed longitudinally, by linkage of national registers, from date of interview until date of first stroke, death, or end of study on 31 Dec 2014. In total, 8635 twins had any migraineous headache, whereof 3553 had migraine with aura and 5082 had non-aura migraineous headache (including migraine without aura and probable migraine), and 44 769 twins had no migraine. During a mean follow-up time of 11.9 years we observed 1297 incident cases of stroke. The Cox proportional hazards model with attained age as underlying time scale was used to estimate hazard ratios with 95% confidence intervals for stroke including ischaemic and haemorrhagic subtypes related to migraine with aura, non-aura migraineous headache, and any migraineous headache. Analyses were adjusted for gender and cardiovascular risk factors. Where appropriate; within-pair analyses were performed to control for confounding by familial factors. The age- and gender-adjusted hazard ratio for stroke related to migraine with aura was 1.27 (95% confidence interval 1.00-1.62), P = 0.05, and 1.07 (95% confidence interval 0.91-1.26), P = 0

  16. The neonatal outcome in twin versus triplet and quadruplet pregnancies

    Directory of Open Access Journals (Sweden)

    Fatemeh Nasseri

    2009-02-01

    Full Text Available

    • BACKGROUND: To assess the risk of neonatal mortality and morbidity in twin, triplet and quadruplet pregnancies.
    • METHODS: In a retrospective study, the neonatal outcome of all twin, triplet and quadruplet gestations delivered from October 2001 to September 2006 was reviewed. The neonatal outcome of triples and quadruplets was compared with a matched group of twins for gestational age.>
    • RESULTS: During a 5-year period, 511 sets of twin pregnancies, 42 sets of triplet and 5 sets of quadruplet pregnancies were studied. The mean of gestational age for twins, triplets and quadruplets were 33.92 ± 3.5 weeks, 30.92 ± 3.8 weeks and 31.60 ± 2.0 weeks, respectively, (P = 0.0001. Triplets and quadruplets weighed less than twins, (P = 0.0001. Neonatal mortality was 13.5% for twins, 26.8% for triplets and 30% for quadruplets. In vitro fertilization, use of ovulation induction agents, and cesarean delivery in the women with triplet and quadruplet were significantly higher than in those with twin pregnancies, (P = 0.0001. The mean age of mothers with triplets and quadruplets was significantly higher than with twins (P = 0.026. There was not a significant difference in respiratory and non-respiratory short outcomes between triplets, quadruplets and twins when matched for gestational age. Apgar score at 1 and 5 minutes was significantly lower in triplets and quadruplets than twins. There was no influence of birth order on neonatal mortality of triplet pregnancy. Neonatal mortality of triplet births was significantly decreased over the 5 years of the study period.
    • CONCLUSIONS: Triplets and quadruplets have a similar neonatal outcome as twins when matched for gestational age. There is no influence of birth on the neonatal mortality of triplet pregnancy. It appears that outcome is mainly dependent on gestational age.>
    • KEYWORDS: Neonatal

    • 'Twin2twin' an innovative method of empowering midwives to strengthen their professional midwifery organisations.

      Science.gov (United States)

      Cadée, Franka; Perdok, Hilde; Sam, Betty; de Geus, Myrte; Kweekel, Liselotte

      2013-10-01

      midwives need professional support from a national midwifery organisation to be able to provide the services that are by regulatory mechanisms and accreditation expected of them. Not all midwives in the world are united in a professional organisation. The aim of this project was to strengthen the midwifery organisations of Sierra Leone and the Netherlands. During the process of the project it was realised that the development of a platform of exchange at organisational level would be enhanced by introducing personal exchange between individual midwives. In response to this new insight the original project plan was adjusted by incorporating the twin2twin method. twin2twin is a feminist methodology of mutual exchange between twenty pairs of midwives from different organisations (in this case Sierra Leone and the Netherlands). The method can be distinguished by 10 specific steps. It was developed, used and (re)evaluated through focus group discussions, storytelling and written evaluations. twinning of organisations was strengthened by adding a human component to the process. With the use of the 'twin2twin' method, midwives were encouraged to invested in a professional and personal bond with their 'twin sister'. This bond was independent and went beyond the relatively short four year project period. Through personal engagement and mutual exchange of knowledge and skills, midwives empowered each other to build and strengthen their midwifery organisations both in Sierra Leone and the Netherlands. (Empowerment refers to the expansion in people's ability to make strategic life choices in a context where this ability was previously denied to them (Narayan, 2005); organisational empowerment includes processes and structures that enhance members' skills and provides them with the mutual support necessary to effect community level change (Zimmerman, 1995).). despite challenges we are convinced that twin2twin can be of additional benefit for the success of other projects

    • Diabetes and perinatal mortality in twin pregnancies.

      Directory of Open Access Journals (Sweden)

      Zhong-Cheng Luo

      Full Text Available BACKGROUND: Diabetes in pregnancy has been associated with a paradoxically reduced risk of neonatal death in twin pregnancies. Risk "shift" may be a concern in that the reduction in neonatal deaths may be due to an increase in fetal deaths (stillbirths. This study aimed to clarify the impact of diabetes on the risk of perinatal death (neonatal death plus stillbirth in twin pregnancies. METHODS: This was a retrospective cohort study of twin births using the largest available dataset on twin births (the U.S. matched multiple birth data 1995-2000; 19,676 neonates from diabetic pregnancies, 541,481 from non-diabetic pregnancies. Cox proportional hazard models were applied to estimate the adjusted hazard ratios (aHR of perinatal death accounting for twin cluster-level dependence. RESULTS: Comparing diabetic versus non-diabetic twin pregnancies, overall perinatal mortality rate was counterintuitively lower [2.1% versus 3.3%, aHR 0.70 (95% confidence intervals 0.63-0.78]. Individually, both stillbirth and neonatal mortality rates were lower in diabetic pregnancies, but we identified significant differences by gestational age and birth weight. Diabetes was associated with a survival benefit in pregnancies completed before 32 weeks [aHR 0.55 (0.48-0.63] or with birth weight =2500 g [aHR 2.20 (1.55-3.13]. CONCLUSIONS: Diabetes in pregnancy appears to be "protective" against perinatal death in twin pregnancies ending in very preterm or very low birth weight births. Prospective studies are required to clarify whether these patterns of risk are real, or they are artifacts of unmeasured confounders. Additional data correlating these outcomes with the types of diabetes in pregnancy are also needed to distinguish the effects of pre-gestational vs. gestational diabetes.

    • Twin Studies in Autism: What Might They Say about Genetic and Environmental Influences

      Science.gov (United States)

      Anderson, George M.

      2012-01-01

      Genetic and epigenetic differences exist within monozygote twin-pairs and might be especially important in the expression of autism. Assuming phenotypic differences between monozygotic twins are due to environmental influences may lead to mistaken conclusions regarding the relative genetic and environmental contribution to autism risk.

    • Resemblances of Parents and Twins in Sport Participation and Heart Rate

      NARCIS (Netherlands)

      Boomsma, D.I.; van den Bree, M.B.; Orlebeke, J.F.; Molenaar, P.C.M.

      1989-01-01

      A model to analyze resemblances of twins and parents using LISREL is outlined and applied to sports participation and heart-rate data. Sports participation and heart rate were measured in 44 monozygotic and 46 dizygotic adolescent twin pairs and in their parents. Genetic factors influence variation

  1. Does the sex of one's co-twin affect height and BMI in adulthood?

    DEFF Research Database (Denmark)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero

    2017-01-01

    BACKGROUND: The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and th...

  2. The Application of Structural Equation Modeling to Maternal Ratings of Twins' Behavior and Emotional Problems.

    Science.gov (United States)

    Silberg, Judy L.; And Others

    1994-01-01

    Applied structural equation modeling to twin data to assess impact of genetic and environmental factors on children's behavioral and emotional functioning. Applied models to maternal ratings of behavior of 515 monozygotic and 749 dizygotic twin pairs. Importance of genetic, shared, and specific environmental factors for explaining variation was…

  3. Nephrolithiasis in identical twins: the impact of nature vs nurture.

    Science.gov (United States)

    Haleblian, George E; Cantor, David A; Sur, Roger L; Assimos, Dean G; Preminger, Glenn M

    2007-09-01

    To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors. Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed. The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume. These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.

  4. Heritability of Performance Deficit Accumulation During Acute Sleep Deprivation in Twins

    Science.gov (United States)

    Kuna, Samuel T.; Maislin, Greg; Pack, Frances M.; Staley, Bethany; Hachadoorian, Robert; Coccaro, Emil F.; Pack, Allan I.

    2012-01-01

    Study Objectives: To determine if the large and highly reproducible interindividual differences in rates of performance deficit accumulation during sleep deprivation, as determined by the number of lapses on a sustained reaction time test, the Psychomotor Vigilance Task (PVT), arise from a heritable trait. Design: Prospective, observational cohort study. Setting: Academic medical center. Participants: There were 59 monozygotic (mean age 29.2 ± 6.8 [SD] yr; 15 male and 44 female pairs) and 41 dizygotic (mean age 26.6 ± 7.6 yr; 15 male and 26 female pairs) same-sex twin pairs with a normal polysomnogram. Interventions: Thirty-eight hr of monitored, continuous sleep deprivation. Measurements and Results: Patients performed the 10-min PVT every 2 hr during the sleep deprivation protocol. The primary outcome was change from baseline in square root transformed total lapses (response time ≥ 500 ms) per trial. Patient-specific linear rates of performance deficit accumulation were separated from circadian effects using multiple linear regression. Using the classic approach to assess heritability, the intraclass correlation coefficients for accumulating deficits resulted in a broad sense heritability (h2) estimate of 0.834. The mean within-pair and among-pair heritability estimates determined by analysis of variance-based methods was 0.715. When variance components of mixed-effect multilevel models were estimated by maximum likelihood estimation and used to determine the proportions of phenotypic variance explained by genetic and nongenetic factors, 51.1% (standard error = 8.4%, P sleep deprivation. Citation: Kuna ST; Maislin G; Pack FM; Staley B; Hachadoorian R; Coccaro EF; Pack AI. Heritability of performance deficit accumulation during acute sleep deprivation in twins. SLEEP 2012;35(9):1223-1233. PMID:22942500

  5. Has the "Equal Environments" assumption been tested in twin studies?

    Science.gov (United States)

    Eaves, Lindon; Foley, Debra; Silberg, Judy

    2003-12-01

    A recurring criticism of the twin method for quantifying genetic and environmental components of human differences is the necessity of the so-called "equal environments assumption" (EEA) (i.e., that monozygotic and dizygotic twins experience equally correlated environments). It has been proposed to test the EEA by stratifying twin correlations by indices of the amount of shared environment. However, relevant environments may also be influenced by genetic differences. We present a model for the role of genetic factors in niche selection by twins that may account for variation in indices of the shared twin environment (e.g., contact between members of twin pairs). Simulations reveal that stratification of twin correlations by amount of contact can yield spurious evidence of large shared environmental effects in some strata and even give false indications of genotype x environment interaction. The stratification approach to testing the equal environments assumption may be misleading and the results of such tests may actually be consistent with a simpler theory of the role of genetic factors in niche selection.

  6. Beliefs and practices concerning twins, hermaphrodites, and albinos among the Bamana and Maninka of Mali.

    Science.gov (United States)

    Imperato, Gavin H; Imperato, Pascal James

    2006-06-01

    The Bamana and Maninka of Mali greatly value twins, and have elaborated a range of cultural beliefs and practices to assure their survival. Rates of twinning among these two ethnic groups average from 15.2/1000 to 17.9/1000 births compared to 10.5/1000 births (without assisted reproduction) in the United States and Great Britain. Twins (flaniw) are regarded as extraordinary beings with unusual powers, and as a gift from the supreme deity. A small altar (sinzin) is maintained in the home of twins, and periodic sacrifices of chicken blood, kola nuts, millet paste and millet beer regularly made to assure their protection. Albinos (yéfeguéw) and true and pseudo-hermaphrodites (tyéténousotéw) are also considered twin beings. However, they are believed to be the result of aberrant parental social behavior. The Bamana and Maninka believe that all four groups (twins, albinos, hermaphrodites, and pseudo-harmaphrodites) are closely linked to Faro, an androgynous supernatural being who provides equilibrium in the world. Faro is the original albino and hermaphrodite who gave birth to the first pair of twins after self-impregnation. Whenever a twin dies, a small wooden statue is sculpted called a flanitokélé (twin that remains). This commemorative figure is kept close to the surviving twin, reflecting a belief in the inseparability of twins. Eventually, the surviving twin takes responsibility for the figure. When a surviving twin marries, another figure is often sculpted in the opposite sex from the deceased twin, and placed with the original sculpture. Such commemorative sculptures are not created upon the death of those who are albinos, hermaphrodites, or pseudo-hermaphrodites. In recent years, transformational belief patterns have evolved as increasing numbers of Bamana and Maninka embrace Islam. Traditional beliefs are often given Islamic myths of origin. However, even in this Islamic context, many practices that assure twin survival are maintained.

  7. Intra-uterine exposure to dual fetal programming sequences among surviving co-twins.

    Science.gov (United States)

    Salihu, Hamisu M; Ibrahimou, Boubakari; Dagne, Getachew A

    2011-01-01

    The dynamics of fetal programming following in utero demise of a co-twin are poorly understood. The authors examined fetal programming using a unique application of the change-point analysis method, and identified two types of fetal programming that occurred when a viable twin sibling died in utero, while the co-twin survived. In one type, the initial twin fetal programming trajectory was maintained while in a subset of surviving co-twins a "switch" from a twin to a singleton fetal program (dual fetal programming exposure) was observed. The results suggest that the timing in utero of conversion from a twin to a singleton programming pattern occurred slightly earlier among opposite-sex than in same-sex surviving co-twins. For the conversion from a twin to a singleton program to happen, the surviving co-twin must have attained a "critical mass" when the twin sibling died. Whereas, for same-sex surviving co-twins the critical mass for conversion was the 80th percentile of gestational-age specific birth weight, opposite-sex surviving co-twins converted at a lower critical mass (70th percentile). These novel findings warrant further study to confirm the new hithertofore unknown phenomenon of dual fetal programming sequence, and to determine the implications in terms of subsequent morbidity or mortality during infancy, childhood and adult life.

  8. Digital Twins in Health Care: Ethical Implications of an Emerging Engineering Paradigm

    Directory of Open Access Journals (Sweden)

    Koen Bruynseels

    2018-02-01

    Full Text Available Personalized medicine uses fine grained information on individual persons, to pinpoint deviations from the normal. ‘Digital Twins’ in engineering provide a conceptual framework to analyze these emerging data-driven health care practices, as well as their conceptual and ethical implications for therapy, preventative care and human enhancement. Digital Twins stand for a specific engineering paradigm, where individual physical artifacts are paired with digital models that dynamically reflects the status of those artifacts. When applied to persons, Digital Twins are an emerging technology that builds on in silico representations of an individual that dynamically reflect molecular status, physiological status and life style over time. We use Digital Twins as the hypothesis that one would be in the possession of very detailed bio-physical and lifestyle information of a person over time. This perspective redefines the concept of ‘normality’ or ‘health,’ as a set of patterns that are regular for a particular individual, against the backdrop of patterns observed in the population. This perspective also will impact what is considered therapy and what is enhancement, as can be illustrated with the cases of the ‘asymptomatic ill’ and life extension via anti-aging medicine. These changes are the consequence of how meaning is derived, in case measurement data is available. Moral distinctions namely may be based on patterns found in these data and the meanings that are grafted on these patterns. Ethical and societal implications of Digital Twins are explored. Digital Twins imply a data-driven approach to health care. This approach has the potential to deliver significant societal benefits, and can function as a social equalizer, by allowing for effective equalizing enhancement interventions. It can as well though be a driver for inequality, given the fact that a Digital Twin might not be an accessible technology for everyone, and given the fact

  9. Digital Twins in Health Care: Ethical Implications of an Emerging Engineering Paradigm

    Science.gov (United States)

    Bruynseels, Koen; Santoni de Sio, Filippo; van den Hoven, Jeroen

    2018-01-01

    Personalized medicine uses fine grained information on individual persons, to pinpoint deviations from the normal. ‘Digital Twins’ in engineering provide a conceptual framework to analyze these emerging data-driven health care practices, as well as their conceptual and ethical implications for therapy, preventative care and human enhancement. Digital Twins stand for a specific engineering paradigm, where individual physical artifacts are paired with digital models that dynamically reflects the status of those artifacts. When applied to persons, Digital Twins are an emerging technology that builds on in silico representations of an individual that dynamically reflect molecular status, physiological status and life style over time. We use Digital Twins as the hypothesis that one would be in the possession of very detailed bio-physical and lifestyle information of a person over time. This perspective redefines the concept of ‘normality’ or ‘health,’ as a set of patterns that are regular for a particular individual, against the backdrop of patterns observed in the population. This perspective also will impact what is considered therapy and what is enhancement, as can be illustrated with the cases of the ‘asymptomatic ill’ and life extension via anti-aging medicine. These changes are the consequence of how meaning is derived, in case measurement data is available. Moral distinctions namely may be based on patterns found in these data and the meanings that are grafted on these patterns. Ethical and societal implications of Digital Twins are explored. Digital Twins imply a data-driven approach to health care. This approach has the potential to deliver significant societal benefits, and can function as a social equalizer, by allowing for effective equalizing enhancement interventions. It can as well though be a driver for inequality, given the fact that a Digital Twin might not be an accessible technology for everyone, and given the fact that patterns

  10. Are twins at risk of cancer: results from the Swedish family-cancer database.

    Science.gov (United States)

    Hemminki, Kari; Chen, Bowang

    2005-10-01

    A few twin studies on cancer have addressed questions on the possible carcinogenic or protective effects of twining by comparing the occurrence of cancer in twins and singletons. The nationwide Swedish Family-Cancer Database of 10.2 million individuals and 69,654 0- to 70-year-old twin pairs were used to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for all main cancers compared to singletons. The overall risk of cancer in same- or different-sex twins was at the same level as the risk for singletons. Testicular cancer, particularly seminoma, was increased among same-sex twins (1.54) and all twins to an SIR of 1.38. Among other tumors, neurinomas and non-thyroid endocrine gland tumors were increased. Colorectal cancers and leukemia were decreased among all twins. Melanoma and squamous cell skin cancer were decreased in male same-sex twins. The data on this unselected population of twins suggest that twinning per se is not a risk factor of cancer. In utero hormonal exposures or postnatal growth stimulation may be related to the risk of testicular cancer and pituitary tumors. Protective effects against colorectal cancer may be related to a beneficial diet, and in melanoma and skin cancer, to socioeconomic factors. The study involved multiple comparisons, and internal consistency between the results was one of the main factors considered for their plausibility. The results should encourage others working on twin and singleton populations to examine the specific associations and emerging hypotheses.

  11. Chromosomal Aberrations in Monozygotic and Dizygotic Twins Versus Singletons in Denmark During 1968-2009

    DEFF Research Database (Denmark)

    Kristensen, Lone Krøldrup; Larsen, Lisbeth A; Fagerberg, Christina

    2017-01-01

    BACKGROUND: Hall (Embryologic development and monozygotic twinning. Acta Geneticae Medicae et Gemellologiae, Vol. 45, 1996, pp. 53-57) hypothesized that chromosomal aberrations can lead to monozygotic (MZ) twinning. However, twinning and chromosomal aberrations increase prenatal mortality and could...... reduce the prevalence of chromosomal aberrations in live-born twins. We compared prevalence proportion ratios (PPR) of chromosomal aberrations and trisomy 21 (T21) in live-born twins versus singletons born in Denmark during 1968-2009. METHODS: We linked the Danish Twin Registry and a 5% random sample...... of all singletons to the Danish Cytogenetic Central Register and calculated PPR adjusted for maternal age for MZ, dizygotic (DZ), and all twins versus singletons. Zygosity was based on questionnaires or genetic markers. RESULTS: No overall difference in risk of chromosomal aberrations or T21 in twins...

  12. Origins of Individual Differences in Imitation: Links with Language, Pretend Play, and Socially Insightful Behavior in Two-Year-Old Twins

    Science.gov (United States)

    McEwen, Fiona; Happe, Francesca; Bolton, Patrick; Rijsdijk, Fruhling; Ronald, Angelica; Dworzynski, Katharina; Plomin, Robert

    2007-01-01

    Imitation, vocabulary, pretend play, and socially insightful behavior were investigated in 5,206 same- and opposite-sex 2-year-old twin pairs in the United Kingdom. Individual differences in imitative ability were due to modest heritability (30%), while environmental factors shared between twins (42%) and unique to each twin (28%) also made…

  13. Medical and sociological study on the A-bombed twins, 3

    International Nuclear Information System (INIS)

    Satow, Yukio; Okamoto, Naomasa; Watanabe, Shoji; Ohkita, Takeshi; Kurihara, Minoru

    1980-01-01

    Three A-bomb exposed and nonexposed pairs of monoxygotic twins were investigated. In two pairs of them, environmental factors had no apparent influence, and genetic factors were dominant. In the other one pair, one of which was a A-bomb survivor exposed at 1.5 km from the explosion center, environmental factors and various effects on them. (Ueda, J.)

  14. Adult Empathy: Possible Gender Differences in Gene-Environment Architecture for Cognitive and Emotional Components in a Large Italian Twin Sample.

    Science.gov (United States)

    Toccaceli, Virgilia; Fagnani, Corrado; Eisenberg, Nancy; Alessandri, Guido; Vitale, Augusto; Stazi, Maria Antonietta

    2018-04-15

    Empathy plays a central role in prosocial behavior and human cooperation. Very few twin researchers have investigated innate and environmental effects in adult empathy, and twin research on gender differences in these effects is sparse. The goal of this study was to examine innate and environmental influences on three components of an empathy scale frequently used with adults - the expression of cognitive (CE), emotional (EE), and social skills (SS) empathy - and to explore gender differences in the influences. Study participants were ~1,700 twins (18-65 years) enrolled in the Italian Twin Registry. Empathy was assessed with the Italian version of the Empathy Quotient (EQ), for which the three-factor structure (i.e., CE, EE, and SS) was confirmed. Twin correlations in monozygotic and dizygotic pairs, and males and females were estimated for the total EQ and subscale scores, and univariate genetic model fitting was carried out. Women's empathy (i.e., total EQ as well as CE and EE subdimensions) was predominantly driven by genetic factors and individual experiences, whereas for males, no genetic contribution or important shared and individual environmental effects emerged. Although of large magnitude, the gender differences did not reach statistical significance. Age did not moderate empathy heritability in adulthood. Only for the SS subscale were genetic and environmental proportions of variance similar for men and women. This study suggests possible gender-specific innate and environmental influences on empathy and its cognitive and emotional components that need to be confirmed in future studies.

  15. Twin-twin transfusion syndrome: etiology, severity and rational management

    NARCIS (Netherlands)

    van Gemert, M. J.; Umur, A.; Tijssen, J. G.; Ross, M. G.

    2001-01-01

    The twin-twin transfusion syndrome is a serious complication of monochorionic twin pregnancies. Partly as a result of an inadequate understanding of the pathophysiology of the syndrome, there is a lack of consensus in clinical management. We sought to review the available information on the etiology

  16. The heritability of insomnia progression during childhood/adolescence: results from a longitudinal twin study.

    Science.gov (United States)

    Barclay, Nicola L; Gehrman, Philip R; Gregory, Alice M; Eaves, Lindon J; Silberg, Judy L

    2015-01-01

    To determine prevalence and heritability of insomnia during middle/late childhood and adolescence; examine longitudinal associations in insomnia over time; and assess the extent to which genetic and environmental factors on insomnia remain stable, or whether new factors come into play, across this developmental period. Longitudinal twin study. Academic medical center. There were 739 complete monozygotic twin pairs (52%) and 672 complete dizygotic twin pairs (48%) initially enrolled and were followed up at three additional time points (waves). Mode ages at each wave were 8, 10, 14, and 15 y (ages ranged from 8-18 y). None. Clinical ratings of insomnia symptoms were assessed using the Child and Adolescent Psychiatric Assessment (CAPA) by trained clinicians, and rated according to Diagnostic and Statistical Manual of Mental Disorders (DSM)-III-R criteria for presence of 'clinically significant insomnia', over four sequential waves. Insomnia symptoms were prevalent but significantly decreased across the four waves (ranging from 16.6% to 31.2%). 'Clinically significant insomnia' was moderately heritable at all waves (h² range = 14% to 38%), and the remaining source of variance was the nonshared environment. Multivariate models indicated that genetic influences at wave 1 contributed to insomnia at all subsequent waves, and that new genetic influences came into play at wave 2, which further contributed to stability of symptoms. Nonshared environmental influences were time-specific. Insomnia is prevalent in childhood and adolescence, and is moderately heritable. The progression of insomnia across this developmental time period is influenced by stable as well as new genetic factors that come into play at wave 2 (modal age 10 y). Molecular genetic studies should now identify genes related to insomnia progression during childhood and adolescence. © 2014 Associated Professional Sleep Societies, LLC.

  17. Anencephaly with incomplete twinning (diprosopus).

    Science.gov (United States)

    Riccardi, V M; Bergmann, C A

    1977-10-01

    A case of diprosopus with anencephaly is presented. It is suggested that such concurrence of neural tube defects and incomplete twinning corroborates the notion that a single pathogenetic mechanism may be common to both neural tube defects and monozygotic twinning.

  18. Mahonian pairs

    OpenAIRE

    Sagan, Bruce E.; Savage, Carla D.

    2012-01-01

    We introduce the notion of a Mahonian pair. Consider the set, P^*, of all words having the positive integers as alphabet. Given finite subsets S,T of P^*, we say that (S,T) is a Mahonian pair if the distribution of the major index, maj, over S is the same as the distribution of the inversion number, inv, over T. So the well-known fact that maj and inv are equidistributed over the symmetric group, S_n, can be expressed by saying that (S_n,S_n) is a Mahonian pair. We investigate various Mahonia...

  19. Heritability of performance deficit accumulation during acute sleep deprivation in twins.

    Science.gov (United States)

    Kuna, Samuel T; Maislin, Greg; Pack, Frances M; Staley, Bethany; Hachadoorian, Robert; Coccaro, Emil F; Pack, Allan I

    2012-09-01

    To determine if the large and highly reproducible interindividual differences in rates of performance deficit accumulation during sleep deprivation, as determined by the number of lapses on a sustained reaction time test, the Psychomotor Vigilance Task (PVT), arise from a heritable trait. Prospective, observational cohort study. Academic medical center. There were 59 monozygotic (mean age 29.2 ± 6.8 [SD] yr; 15 male and 44 female pairs) and 41 dizygotic (mean age 26.6 ± 7.6 yr; 15 male and 26 female pairs) same-sex twin pairs with a normal polysomnogram. Thirty-eight hr of monitored, continuous sleep deprivation. Patients performed the 10-min PVT every 2 hr during the sleep deprivation protocol. The primary outcome was change from baseline in square root transformed total lapses (response time ≥ 500 ms) per trial. Patient-specific linear rates of performance deficit accumulation were separated from circadian effects using multiple linear regression. Using the classic approach to assess heritability, the intraclass correlation coefficients for accumulating deficits resulted in a broad sense heritability (h(2)) estimate of 0.834. The mean within-pair and among-pair heritability estimates determined by analysis of variance-based methods was 0.715. When variance components of mixed-effect multilevel models were estimated by maximum likelihood estimation and used to determine the proportions of phenotypic variance explained by genetic and nongenetic factors, 51.1% (standard error = 8.4%, P performance deficit accumulations on PVT during sleep deprivation.

  20. Prospective risk of stillbirth and neonatal complications in twin pregnancies

    DEFF Research Database (Denmark)

    Cheong-See, Fiona; Schuit, Ewoud; Arroyo-Manzano, David

    2016-01-01

    OBJECTIVE: To determine the risks of stillbirth and neonatal complications by gestational age in uncomplicated monochorionic and dichorionic twin pregnancies. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Medline, Embase, and Cochrane databases (until December 2015). REVIEW METHODS: ...

  1. Relativistic twins or sextuplets?

    International Nuclear Information System (INIS)

    Sheldon, Eric

    2003-01-01

    A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but entailed a pedagogic hurdle which the present treatment aims to surmount. Two scenarios are presented: the first 'flight-plan' is akin to that depicted by Soni, with constant-velocity segments, while the second portrays an alternative mission undertaken with sustained acceleration and deceleration, illustrated quantitatively for a two-way spacecraft flight from Earth to Polaris (465.9 light years distant) and back

  2. Relativistic twins or sextuplets?

    CERN Document Server

    Sheldon, E S

    2003-01-01

    A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but entailed a pedagogic hurdle which the present treatment aims to surmount. Two scenarios are presented: the first 'flight-plan' is akin to that depicted by Soni, with constant-velocity segments, while the second portrays an alternative mission undertaken with sustained acceleration and deceleration, illustrated quantitatively for a two-way spacecraft flight from Earth to Polaris (465.9 light years distant) and back.

  3. Imaging of conjoined twins

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, Kieran [Great Ormond Street Hospital for Children, Department of Radiology, London (United Kingdom); Kiely, Edward M.; Spitz, Lewis [Great Ormond Street Hospital for Children, Department of Surgery, London (United Kingdom)

    2006-09-15

    The incidence of conjoined twins is estimated to be around 1 in 250,000 live births. There is a distinct female predominance. In this paper the imaging of conjoined twins both antenatally and postnatally is reviewed, in particular taking into consideration recent advances with multidetector CT. Accurate counselling of parents regarding the likely outcome of the pregnancy and the likelihood of successful separation is dependent on good prenatal imaging with ultrasound and MRI. Planning of postnatal surgical separation is aided by accurate preoperative imaging which, depending on the conjoined area, will encompass many imaging modalities, but often relies heavily on CT scanning. (orig.)

  4. Imaging of conjoined twins

    International Nuclear Information System (INIS)

    McHugh, Kieran; Kiely, Edward M.; Spitz, Lewis

    2006-01-01

    The incidence of conjoined twins is estimated to be around 1 in 250,000 live births. There is a distinct female predominance. In this paper the imaging of conjoined twins both antenatally and postnatally is reviewed, in particular taking into consideration recent advances with multidetector CT. Accurate counselling of parents regarding the likely outcome of the pregnancy and the likelihood of successful separation is dependent on good prenatal imaging with ultrasound and MRI. Planning of postnatal surgical separation is aided by accurate preoperative imaging which, depending on the conjoined area, will encompass many imaging modalities, but often relies heavily on CT scanning. (orig.)

  5. Association between intake of dairy products and short-term memory with and without adjustment for genetic and family environmental factors: A twin study.

    Science.gov (United States)

    Ogata, Soshiro; Tanaka, Haruka; Omura, Kayoko; Honda, Chika; Hayakawa, Kazuo

    2016-04-01

    Previous studies have indicated associations between intake of dairy products and better cognitive function and reduced risk of dementia. However, these studies did not adjust for genetic and family environmental factors that may influence food intake, cognitive function, and metabolism of dairy product nutrients. In the present study, we investigated the association between intake of dairy products and short-term memory with and without adjustment for almost all genetic and family environmental factors using a genetically informative sample of twin pairs. A cross-sectional study was conducted among twin pairs aged between 20 and 74. Short-term memory was assessed as primary outcome variable, intake of dairy products was analyzed as the predictive variable, and sex, age, education level, marital status, current smoking status, body mass index, dietary alcohol intake, and medical history of hypertension or diabetes were included as possible covariates. Generalized estimating equations (GEE) were performed by treating twins as individuals and regression analyses were used to identify within-pair differences of a twin pair to adjust for genetic and family environmental factors. Data are reported as standardized coefficients and 95% confidence intervals (CI). Analyses were performed on data from 78 men and 278 women. Among men, high intake of dairy products was significantly associated with better short-term memory after adjustment for the possible covariates (standardized coefficients = 0.22; 95% CI, 0.06-0.38) and almost all genetic and family environmental factors (standardized coefficients = 0.38; 95% CI, 0.07-0.69). Among women, no significant associations were found between intake of dairy products and short-term memory. Subsequent sensitivity analyses were adjusted for small samples and showed similar results. Intake of dairy product may prevent cognitive declines regardless of genetic and family environmental factors in men. Copyright © 2015 Elsevier Ltd

  6. Blood pressure in young adulthood and residential greenness in the early-life environment of twins.

    Science.gov (United States)

    Bijnens, Esmée M; Nawrot, Tim S; Loos, Ruth Jf; Gielen, Marij; Vlietinck, Robert; Derom, Catherine; Zeegers, Maurice P

    2017-06-05

    Previous research shows that, besides risk factors in adult life, the early-life environment can influence blood pressure and hypertension in adults. However, the effects of residential traffic exposure and residential greenness in the early-life on blood pressure in young adulthood are currently unknown. Ambulatory (24-h) blood pressures of 278 twins (132 pairs) of the East Flanders Prospective Twins Study were obtained at the age of 18 to 25 years. Prenatal and adulthood residential addresses were geocoded and used to assign prenatal and postnatal traffic and greenness indicators. Mixed modelling was performed to investigate blood pressure in association with greenness while adjusting for potential confounding factors. Night-time systolic blood pressure was inversely associated with greenness at the residential address in twins living at the same address their entire life (non-movers, n = 97, 34.9%). An interquartile increase in residential greenness exposure (1000 m radius) was associated with a 3.59 mmHg (95% CI: -6.0 to -1.23; p = 0.005) lower adult night systolic blood pressure. Among twins who were living at a different address than their birth address at time of the measurement (n = 181, 65.1%), night-time blood pressure was inversely associated with residential surrounding greenness at adult age as well as with residential greenness in early-life. However after additional adjustment for residential greenness exposure in adulthood, only residential greenness exposure in early-life was significantly associated with night systolic blood pressure. While no significant effect of adult residential greenness with adult blood pressure was observed, while accounting for the early-life greenness exposure. Lower residential greenness in the early-life environment was independently associated with a higher adult blood pressure. This indicates that residential greenness has persistent effects on blood pressure.

  7. Measurement of low-mass e{sup +}e{sup -} pair production in 2 AGeV C-C collisions with HADES

    Energy Technology Data Exchange (ETDEWEB)

    Sudol, Malgorzata

    2007-07-01

    The search for a modification of hadron properties inside nuclear matter at normal and/or high temperature and density is one of the most interesting issues of modern nuclear physics. Dilepton experiments, give insight into the properties of strong interaction and the nature of hadron mass generation. One of these research tools is the HADES spectrometer. HADES is a high acceptance dilepton spectrometer installed at the heavy-ion synchrotron (SIS) at GSI, Darmstadt. The main physics motivation of HADES is the measurement of e{sup +}e{sup -} pairs in the invariant-mass range up to 1 GeV/c{sup 2} in pion- and proton-induced reactions, as well as in heavy-ion collisions. The goal is to investigate the properties of the vector mesons {rho}, {omega} and of other hadrons reconstructed from e{sup +}e{sup -} decay pairs. Dileptons are penetrating probes allowing to study the in-medium properties of hadrons. However, the measurement of such dilepton pairs is difficult because of a very large background from other processes in which leptons are created. This thesis presents the analysis of the data provided by the first physics run with the HADES spectrometer. For the first time e{sup +}e{sup -} pairs produced in C+C collisions at an incident energy of 2 GeV per nucleon have been collected with sufficient statistics. This experiment is of particular importance since it allows to address the puzzling pair excess measured by the former DLS experiment at a beam energy 1.04 AGeV. The thesis consists of five chapters. The first chapter presents the physics case which is addressed in the work. In the second chapter the HADES spectrometer is introduced with the characteristic of specific detectors which are part of the spectrometer. Chapter three focusses on the issue of charged-particle identification. The fourth chapter discusses the reconstruction of the di-electron spectra in C+C collisions. In this part of the thesis a comparison with theoretical models is included as well

  8. Genetic influences on variation in female orgasmic function: a twin study

    Science.gov (United States)

    Dunn, Kate M; Cherkas, Lynn F; Spector, Tim D

    2005-01-01

    Orgasmic dysfunction in females is commonly reported in the general population with little consensus on its aetiology. We performed a classical twin study to explore whether there were observable genetic influences on female orgasmic dysfunction. Adult females from the TwinsUK register were sent a confidential survey including questions on sexual problems. Complete responses to the questions on orgasmic dysfunction were obtained from 4037 women consisting of 683 monozygotic and 714 dizygotic pairs of female twins aged between 19 and 83 years. One in three women (32%) reported never or infrequently achieving orgasm during intercourse, with a corresponding figure of 21% during masturbation. A significant genetic influence was seen with an estimated heritability for difficulty reaching orgasm during intercourse of 34% (95% confidence interval 27–40%) and 45% (95% confidence interval 38–52%) for orgasm during masturbation. These results show that the wide variation in orgasmic dysfunction in females has a genetic basis and cannot be attributed solely to cultural influences. These results should stimulate further research into the biological and perhaps evolutionary processes governing female sexual function. PMID:17148182

  9. Epigenetic Variation in Monozygotic Twins: A Genome-Wide Analysis of DNA Methylation in Buccal Cells

    Directory of Open Access Journals (Sweden)

    Jenny van Dongen

    2014-05-01

    Full Text Available DNA methylation is one of the most extensively studied epigenetic marks in humans. Yet, it is largely unknown what causes variation in DNA methylation between individuals. The comparison of DNA methylation profiles of monozygotic (MZ twins offers a unique experimental design to examine the extent to which such variation is related to individual-specific environmental influences and stochastic events or to familial factors (DNA sequence and shared environment. We measured genome-wide DNA methylation in buccal samples from ten MZ pairs (age 8–19 using the Illumina 450k array and examined twin correlations for methylation level at 420,921 CpGs after QC. After selecting CpGs showing the most variation in the methylation level between subjects, the mean genome-wide correlation (rho was 0.54. The correlation was higher, on average, for CpGs within CpG islands (CGIs, compared to CGI shores, shelves and non-CGI regions, particularly at hypomethylated CpGs. This finding suggests that individual-specific environmental and stochastic influences account for more variation in DNA methylation in CpG-poor regions. Our findings also indicate that it is worthwhile to examine heritable and shared environmental influences on buccal DNA methylation in larger studies that also include dizygotic twins.

  10. Trends in the obstetric features and management of twin pregnancies.

    LENUS (Irish Health Repository)

    Smith, K E

    2010-03-01

    There are no reports outlining the trends in obstetric features and clinical management of twin pregnancies in an Irish obstetric population. The aim of this study was to investigate these factors for all twin pregnancies delivered during the 19 year period between 1989 and 2007, at Galway University Hospital (GUH). There were 52,199 infants delivered at GUH, of which 1594 infants (3.05% of births) were twins, related to 797 twin pregnancies. The overall incidence of twin pregnancies was 1.52%, increasing from 0.8%-1.0% in the early years of the study to 1.7-1.8% in the latter years of the study (P<0.001). There was a significant increase in incidence of twins born to mothers aged 30-39 years, alongside a significant reduction to mothers aged 20-29 years (P<0.01). The caesarean section rate overall was 41.5% (331\\/797), of which 54% (n=179) were elective, and 46% (n=152) were emergency, representing an emergency caesarean section rate of 19.1% of all twin pregnancies, and of 24.6% after exclusion of elective caesarean sections. The caesarean section rate for twins increased from 30% in 1989 to greater than 50% in the latter years of the study (P<0.01), related largely to a significant increase in elective caesarean sections (P<0.01). The combined vaginal-caesarean delivery rate was remarkably low at 0.75% of all twin pregnancies, and 1% after exclusion of elective caesarean sections. The preterm delivery rates were 4.1% (<32 weeks), and 16.3% (<36 weeks), with an overall perinatal mortality rate of 37 per 1000. These findings highlight the altered demographic and clinical aspects of twin pregnancies in an Irish obstetric population.

  11. Quasi-causal associations of physical activity and neighborhood walkability with body mass index: a twin study.

    Science.gov (United States)

    Duncan, Glen E; Cash, Stephanie Whisnant; Horn, Erin E; Turkheimer, Eric

    2015-01-01

    Physical activity, neighborhood walkability, and body mass index (BMI, kg/m(2)) associations were tested using quasi-experimental twin methods. We hypothesized that physical activity and walkability were independently associated with BMI within twin pairs, controlling for genetic and environmental background shared between them. Data were from 6376 (64% female; 58% identical) same-sex pairs, University of Washington Twin Registry, 2008-2013. Neighborhood walking, moderate-to-vigorous physical activity (MVPA), and BMI were self-reported. Residential address was used to calculate walkability. Phenotypic (non-genetically informed) and biometric (genetically informed) regression was employed, controlling for age, sex, and race. Walking and MVPA were associated with BMI in phenotypic analyses; associations were attenuated but significant in biometric analyses (PsWalkability was not associated with BMI, however, was associated with walking (but not MVPA) in both phenotypic and biometric analyses (Pswalkability is not associated with BMI, it is associated with neighborhood walking (but not MVPA) accounting for shared background, suggesting a causal relationship between them. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. The Placenta in Twin-to-Twin Transfusion Syndrome and Twin Anemia Polycythemia Sequence.

    Science.gov (United States)

    Couck, Isabel; Lewi, Liesbeth

    2016-06-01

    Twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) are complications unique to monochorionic twin pregnancies and their shared circulation. Both are the result of the transfusion imbalance in the intertwin circulation. TTTS is characterized by an amniotic fluid discordance, whereas in TAPS, there is a severe discordance in hemoglobin levels. The article gives an overview of the typical features of TTTS and TAPS placentas.

  13. Genetic and environmental relationships between change in weight and insulin resistance: the Healthy Twin Study.

    Science.gov (United States)

    Song, Yun-Mi; Lee, Kayoung; Sung, Joohon

    2014-06-01

    We aimed to investigate the association between weight change from 20 years of age and insulin resistance (IR), and genetic and environmental relationships between these traits. In 594 Korean twins and family members (209 men, 385 women, 44.0 ± 10.8 years old), the percentage of weight change was calculated using self-reported body weight at 20 years of age and currently measured bodyweight. IR traits were assessed using fasting plasma glucose and insulin, the homeostasis model assessment of IR index (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI). Linear mixed analysis was applied after adjusting for household, body mass index (BMI) at the age of 20 years, age, sex, alcohol, smoking, physical activity, and caloric intake. Heritabilities and genetic and environmental correlations were estimated after adjusting for covariates. In 55 monozygotic twin pairs discordant for HOMA-IR level by >0.3, a conditional logistic regression analysis was conducted regarding weight change. Increases in glucose, insulin, and HOMA-IR and a decrease in QUICKI were associated with a higher percentage of weight change (p change since 20 years old, after adjusting for lifestyle-related factors. In conclusion, both genetic and environmental influences played significant roles in the positive association between weight change from 20 years of age and IR.

  14. Placental share and hemoglobin level in relation to birth weight in twin anemia-polycythemia sequence.

    Science.gov (United States)

    Zhao, D; Slaghekke, F; Middeldorp, J M; Duan, T; Oepkes, D; Lopriore, E

    2014-12-01

    Twin anemia-polycythemia sequence (TAPS) is a newly described form of chronic twin transfusion. Previous observational studies noted a discordance between birth weight and individual placental share in TAPS. The purpose of this study was to investigate if fetal growth in monochorionic (MC) twins with TAPS is determined by placental share or by the net inter-twin blood transfusion. All consecutive MC twin placentas of live-born twin pairs with and without TAPS examined at our center between June 2002 and February 2014 were included in this study. Hemoglobin (Hb) levels and individual placental share were evaluated at birth and correlated with birth weight share. We excluded MC twin pregnancies with twin-twin transfusion syndrome. A total of 270 MC twin pregnancies (TAPS group, n = 20; control group without TAPS, n = 250) were included in this study. Donors with TAPS had a lower birth weight than recipients in 90% (18/20) of cases, but a larger placental share in 65% (13/20) of cases. In the TAPS group, birth weight share was positively correlated with Hb share at birth (P < 0.01) but not with placental share (P = 0.54). In the control group without TAPS, birth weight share was strongly correlated with placental share (P < 0.01) but not with Hb share (P = 0.14). A relatively larger placental share may enable the survival of the anemic twin in TAPS. In contrast with uncomplicated MC twins, fetal growth in MC twins with TAPS is determined primarily by the net inter-twin blood transfusion instead of placental share. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Anaesthesia for conjoined twins

    African Journals Online (AJOL)

    draw~ver patient system consisting of a paediatric. "Ambu" bag and "Paedivalven drawing oxygen-en- riched air through a halothane vaporiser. Oxygen was supplied from an electric oxygen concentrator which can give 2 litres of 95% oxygen per minute. This apparatus has been described I. Mter 3 minutes the Sa02 of Twin ...

  16. Twin study on transplacental-acquired antibodies and attention deficit/hyperactivity disorder - A pilot study

    DEFF Research Database (Denmark)

    Bilenberg, Niels; Hougaard, David; Norgaard-Pedersen, Bent

    2011-01-01

    OBJECTIVE: We hypothesize that maternal transplacentally acquired antibodies may cause Attention Deficit/Hyperactivity Disorder (ADHD) symptoms years after birth, and tested the hypothesis in twins discordant for ADHD symptoms. METHOD: In a pre-screened sample of 7793 same sex twin pair's (4......-18years) questionnaire data on hyperactivity and inattention was collected. Blood samples taken 5days after birth from 190 ADHD-score discordant pairs (15% MZ) were analyzed for antibodies. RESULTS: Pneumococcus Polysaccaride 14 (PnPs14) was present in the ADHD high scoring twin more often than...... in the lower scoring twin (P=0.04). CONCLUSION: Although the study provides no strong support for the hypothesis, infection or immunological factors may be one among several causes of ADHD. The genetic control obtained in a twin design may reduce the exposure contrast and a larger sample is needed to further...

  17. There are two twin shadows, but einstein is one

    Directory of Open Access Journals (Sweden)

    Popović Marko E.

    2012-01-01

    Full Text Available 2011 is the international year of chemistry, and it is exactly 100 years past after the P. Langevin promotion of “twin paradox” problem. The hundred year old problem still demands its solution. Twin paradox, established by a physicist, has been representing a nightmare for philosophers, physicists, chemists, and biologists until these days. After a hundred years, it is time to try to close this page in long history of misunderstanding of the special relativity. This analysis has three main assumptions. First, biological systems are a part of physical world and therefore they behave in accordance to the physical laws according to Schrödinger. Second, according to Von Bertalanffy the biological systems are open thermodynamic systems. Because of that the approach of non-equilibrium thermodynamics was used for analyzing the twin paradox. Third, rise of entropy is according to Hyflick strongly connected with aging. Entropy can be taken as a measure of cell age or even human age according to Silva et al. and Gladyshev. So entropy invariance strongly suggests that both twins should be the same age, so there is a potential problem for twin paradox with the second law. The only possible influence of relativity on the chemical reaction rate is time dilatation. However time flow does not cause the aging process, so time dilatation cannot have any influence on it. So, after detailed analysis, it is concluded that there is no twin paradox in reality. Both twins will be exactly in same thermodynamic state and bio-logical age. The traveler twin will notice time dilatation, but this relativistic effect has no influence on the aging process.

  18. A study of the occurrence of monochorionic and monozygotic twinning in the pig

    DEFF Research Database (Denmark)

    Bjerre, Ditte; Thorup, F.; Jørgensen, Claus Bøttcher

    2009-01-01

    the investigation of porcine monochorionic embryos from 76 sows at days 26-29 post-insemination (p.i.), as well as an examination of 10 whole litters at days 21-22 p.i. In the former group, 29% of the sows carried monochorionic embryos. Based on DNA profiling using microsatellite markers, one monozygotic twin pair...... was found among these embryos. In the latter group, three monozygotic twin pairs were identified. Thus, it can be concluded that although the occurrence of monozygotic twins in pigs is a sporadic event, the fusion of extra-embryonic membranes is relatively common....

  19. Differences in Religiousness in Opposite-Sex and Same-Sex Twins in a Secular Society

    DEFF Research Database (Denmark)

    Juel Ahrenfeldt, Linda; Lindahl-Jacobsen, Rune; Möller, Sören

    2016-01-01

    (RCOPE) for the assessment of positive and negative religious coping patterns. Differences between OS and SS twins were investigated using logistic regression for each sex. The analyses were adjusted for dependence within twin pairs. No significant differences in religiousness and religious coping were......Sex differences in religion are well known, with females generally being more religious than males, and shared environmental factors have been suggested to have a large influence on religiousness. Twins from opposite-sex (OS) and same-sex (SS) pairs may differ because of a dissimilar psycho...

  20. COCACOLA: binning metagenomic contigs using sequence COmposition, read CoverAge, CO-alignment and paired-end read LinkAge.

    Science.gov (United States)

    Lu, Yang Young; Chen, Ting; Fuhrman, Jed A; Sun, Fengzhu

    2017-03-15

    The advent of next-generation sequencing technologies enables researchers to sequence complex microbial communities directly from the environment. Because assembly typically produces only genome fragments, also known as contigs, instead of an entire genome, it is crucial to group them into operational taxonomic units (OTUs) for further taxonomic profiling and down-streaming functional analysis. OTU clustering is also referred to as binning. We present COCACOLA, a general framework automatically bin contigs into OTUs based on sequence composition and coverage across multiple samples. The effectiveness of COCACOLA is demonstrated in both simulated and real datasets in comparison with state-of-art binning approaches such as CONCOCT, GroopM, MaxBin and MetaBAT. The superior performance of COCACOLA relies on two aspects. One is using L 1 distance instead of Euclidean distance for better taxonomic identification during initialization. More importantly, COCACOLA takes advantage of both hard clustering and soft clustering by sparsity regularization. In addition, the COCACOLA framework seamlessly embraces customized knowledge to facilitate binning accuracy. In our study, we have investigated two types of additional knowledge, the co-alignment to reference genomes and linkage of contigs provided by paired-end reads, as well as the ensemble of both. We find that both co-alignment and linkage information further improve binning in the majority of cases. COCACOLA is scalable and faster than CONCOCT, GroopM, MaxBin and MetaBAT. The software is available at https://github.com/younglululu/COCACOLA . fsun@usc.edu. Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  1. Cannabis Involvement and Nonsuicidal Self-Injury: A Discordant Twin Approach.

    Science.gov (United States)

    Few, Lauren R; Grant, Julia D; Nelson, Elliot C; Trull, Timothy J; Grucza, Richard A; Bucholz, Kathleen K; Verweij, Karin J H; Martin, Nicholas G; Statham, Dixie J; Madden, Pamela A F; Heath, Andrew C; Lynskey, Michael T; Agrawal, Arpana

    2016-11-01

    Cannabis use, particularly at an early age, has been linked to suicidal thoughts and behavior, but minimal work has examined the association between cannabis use and lifetime nonsuicidal self-injury (NSSI). The current study aims to characterize the overlap between lifetime and early cannabis use and NSSI and to examine genetic and environmental mechanisms of this association. Adult male and female twins from the Australian Twin Registry (N = 9,583) were used to examine the odds of NSSI associated with lifetime cannabis use and early cannabis use (i.e., accounting for the age at onset of cannabis use and NSSI. Lifetime cannabis use (odds ratio [OR] = 2.84, 95% CI [2.23, 3.61]) and early cannabis use were associated with increased odds of NSSI (OR = 2.15, 95% CI [1.75, 2.65]), and this association remained when accounting for covariates. The association was only significant, however, in MZ twin pairs discordant for early cannabis use (OR = 3.20, 95% CI [1.17, 8.73]). Replication analyses accounting for the temporal ordering of cannabis use and NSSI yielded similar findings of nominal significance. Results suggest that NSSI is associated with cannabis involvement via differing mechanisms. For lifetime cannabis use, the lack of association in discordant pairs suggests the role of shared genes and family environment. However, in addition to such shared familial influences, person-specific and putatively causal factors contribute to the relationship between early cannabis use and NSSI. Therefore, delaying the onset of cannabis use may reduce exposure to influences that exacerbate vulnerabilities to NSSI.

  2. Prenatal Sonographic Diagnosis of Acardiac Twins

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Ah; Song, Mi Jin [Cheil General Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2006-09-15

    This study was performed to present the prenatal sonographic findings and the associated abnormalities of acardiac twins. Seven cases of acardiac twins were reviewed retrospectively. Prenatal ultrasonography was performed in all patients at a gestational age between 12 and 27 weeks (mean 17.6 weeks). Autopsy was performed in four cases. The sonographic and autopsy findings were reviewed to report the associated abnormalities of the acardiac and donor fetuses. The diagnosis of acardiac twins was made on the basis of ultrasonography (n=6) or autopsy (n=1). The associated abnormalities of the acardiac fetuses were single umbilical artery (SUA) (n=5), abdominal wall defect (n=4), club feet (n=4), scoliosis (n=1), cleft lip and palate (n=1), digital anomaly (n=1), and umbilical cord cyst (n=1). In four of the donor fetuses, sonographic abnormalities were found. Autopsy was performed in three of the four cases to reveal hydropic change (n=2), diaphragmatic hernia (n=1) and multiple structural abnormalities of interventricular septal defect, polydactyly, club feet and SUA (n=1). Intrauterine fetal death occurred in five donors and follow-up was lost in the remaining two. Meticulous sonography enables the diagnosis of acardiac twins at an early gestational age and can reveal the associated abnormalities of the donor fetus as well as the acardiac fetus

  3. Prenatal Sonographic Diagnosis of Acardiac Twins

    International Nuclear Information System (INIS)

    Kim, Jeong Ah; Song, Mi Jin

    2006-01-01

    This study was performed to present the prenatal sonographic findings and the associated abnormalities of acardiac twins. Seven cases of acardiac twins were reviewed retrospectively. Prenatal ultrasonography was performed in all patients at a gestational age between 12 and 27 weeks (mean 17.6 weeks). Autopsy was performed in four cases. The sonographic and autopsy findings were reviewed to report the associated abnormalities of the acardiac and donor fetuses. The diagnosis of acardiac twins was made on the basis of ultrasonography (n=6) or autopsy (n=1). The associated abnormalities of the acardiac fetuses were single umbilical artery (SUA) (n=5), abdominal wall defect (n=4), club feet (n=4), scoliosis (n=1), cleft lip and palate (n=1), digital anomaly (n=1), and umbilical cord cyst (n=1). In four of the donor fetuses, sonographic abnormalities were found. Autopsy was performed in three of the four cases to reveal hydropic change (n=2), diaphragmatic hernia (n=1) and multiple structural abnormalities of interventricular septal defect, polydactyly, club feet and SUA (n=1). Intrauterine fetal death occurred in five donors and follow-up was lost in the remaining two. Meticulous sonography enables the diagnosis of acardiac twins at an early gestational age and can reveal the associated abnormalities of the donor fetus as well as the acardiac fetus

  4. Genetic and environmental links between cognitive and physical functions in old age

    DEFF Research Database (Denmark)

    Johnson, Wendy; Deary, Ian J; McGue, Matt

    2009-01-01

    of twins from the Longitudinal Study of Aging Danish Twins. Cognitive function was measured using forward and backward digit span, immediate and delayed memory, and fluency tasks. Physical function was measured using self-report of ability to carry out physical activities including walking, running......In old age, cognitive and physical functions are correlated. Knowing the correlations between genetic and environmental influences underlying this correlation can help to clarify the reasons for the observable (phenotypic) correlation. We estimated these correlations in a sample of 1,053 pairs...

  5. Minority stressors, rumination, and psychological distress in monozygotic twins discordant for sexual minority status.

    Science.gov (United States)

    Timmins, Liam; Rimes, Katharine A; Rahman, Qazi

    2017-11-07

    Lesbian, gay, and bisexual (LGB) individuals report higher levels of depression and anxiety than heterosexual people. Genetic factors may be a 'common cause' of sexual minority status and psychological distress. Alternatively, these may be correlated because of non-genetic environmental factors (e.g. minority stressors). This study investigated minority stressors and distress in monozygotic twins discordant for sexual minority status. This design provides a test of the role of non-shared environmental factors while minimizing differences due to genetics. Thirty-eight twin pairs in which one was heterosexual and the other was LGB completed a survey. Differences between twin pairs in minority stressors, rumination, psychological distress, and gender non-conformity were examined. Associations between these variables were also tested. Although there were no significant group differences for distress, LGB twins had higher rumination, a vulnerability factor for distress, than heterosexual co-twins. LGB twins also had higher scores than heterosexual co-twins on expectations of rejection, active concealment, self-stigma, prejudice events, childhood gender non-conformity, and lower scores on sexual orientation disclosure. Differences between twin pairs in rumination were positively associated with differences in acceptance concerns and self-stigma. Finally, self-stigma was positively associated with rumination in the full sample of heterosexual co-twins and microaggressions were positively associated with rumination when looking at exclusively heterosexual co-twins. These results support environmental factors as a causal explanation for disparities in rumination between LGB and heterosexual individuals. These factors likely include minority stressors. Rumination may also be associated with minority stressors in heterosexual MZ co-twins of LGB individuals.

  6. Skewed X inactivation and survival: a 13-year follow-up study of elderly twins and singletons

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Thinggaard, Mikael; Christiansen, Lene

    2012-01-01

    In mammalian females, one of the two X chromosomes is inactivated in early embryonic life. Females are therefore mosaics for two cell populations, one with the maternal and one with the paternal X as the active X chromosome. A skewed X inactivation is a marked deviation from a 50:50 ratio...... mortality than the majority of women who had a more skewed DS (hazard ratio: 1.30; 95% CI: 1.04-1.64). The association between X inactivation and mortality was replicated in dizygotic twin pairs for which the co-twin with the lowest DS also had a statistically significant tendency to die first in the twin....... In populations of women past 55-60 years of age, an increased degree of skewing (DS) is found. Here the association between age-related skewing and mortality is analyzed in a 13-year follow-up study of 500 women from three cohorts (73-100 years of age at intake). Women with low DS had significantly higher...

  7. Higher Prevalence of Left-Handedness in Twins? Not After Controlling Birth Time Confounders.

    Science.gov (United States)

    Heikkilä, Kauko; Vuoksimaa, Eero; Saari-Kemppainen, Aulikki; Kaprio, Jaakko; Rose, Richard J; Haukka, Jari; Pitkäniemi, Janne; Iivanainen, Matti

    2015-10-01

    Pregnancy- and birth-related factors may have an effect on handedness. Compared with singletons, twins have a lower birth weight, shorter gestational age, and are at higher risk for birth complications. We tested whether the prevalence of left-handedness is higher among twins than singletons, and if so, whether that difference is fully explained by pregnancy and birth-related differences between twins and singletons. We analyzed Finnish population-based datasets; included were 8,786 twins and 5,892 singletons with information on birth weight (n = 12,381), Apgar scores (n = 11,129), and gestational age (n = 11,811). Two twin cohorts were involved: FinnTwin12 included twins born during 1983-1987, and FinnTwin16 included twins born during 1974-1979. We had two comparison groups of singletons: 4,101 individuals born during 1986-1988 and enrolled in the Helsinki Ultrasound Trial, and 1,791 individuals who were partners of FinnTwin16 twins. We used logistic regression models with writing hand as the outcome for comparison and evaluating effects of covariates. Left-handedness was more common in twins (9.67%) than in singletons (8.27%; p = .004). However, Apgar scores were associated with handedness, and after controlling for covariates, we found no difference in the prevalence of left-handedness between twins and singletons. Increased left-handedness among twins, often reported by others, was evident in our data, but only among our older twin cohorts, and that association disappeared after removing effects of perinatal covariates.

  8. Analysis of electron pair production in the collision system Ar+KCl at 1.76 AGeV; Analyse der Elektronpaarproduktion im Stosssystem Ar+KCl bei 1,76 AGeV

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Simon Martin

    2008-06-30

    The HADES-spectrometer at GSI is used to measure the production of the light vector mesons {rho}, {omega} and {phi} at SIS energies. Therefore, the medium sized collision system Ar+KCl was measured at 1.76 AGeV kinetic energy of beam particles. In this system the density of particle tracks is much larger as compared to the formerly used collision system C+C, making it necessary to upgrade the data analysis. The previous method of hard-cuts - used for particle identification - was replaced by a newly developed multi-variate analysis based on an artificial neural network. This algorithm has the benefit, that it is more robust against fluctuations in one or more of the used detector observables. This increases the overall efficiency and purity of the analysis procedure. Furthermore, the reconstruction of particle tracks inside the HADES spectrometer is based on a few position information, only. During analysis of raw data, these information are combined to a artificially large manifold of tracks. This leads to the general problem that one has to select the maximum number of true physical tracks out of this set of tracks per event. A new method of track selection is used to filter the data not only to select single tracks, but also to identify electron pairs created during Dalitz-decay of {pi}{sup 0} mesons, which build the bulk of combinatorial background. The result of the analysis is an efficiency corrected invariant mass spectrum of electron pairs, normalized to the mean number of pions per event. The spectrum consists of more than 16,000 pairs with an invariant mass larger than 150 MeV. In total more than 150000 pairs were found. A first comparison with the spectra calculated by using the old analysis approach shows a 30% enhancement in yield of reconstructed electron pairs. A first comparison with a simple thermal model implemented by the Pluto event generator, opens the possibility to compare the measured pair yield of {omega} and {phi} mesons via m{sub T

  9. Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

    Science.gov (United States)

    Segal, Nancy L

    2016-06-01

    The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

  10. A Twin Study of Objective and Subjective Pubertal Timing and Peer Influence on Risk-Taking.

    Science.gov (United States)

    Kretsch, Natalie; Mendle, Jane; Harden, K Paige

    2016-03-01

    The current study used a behavioral genetic design to test whether three measures of pubertal timing moderated peer influence on risk-taking in a sample of 248 female adolescent twin pairs ( M age =16.0, SD =1.5) from the National Longitudinal Study of Adolescent Health. Peer influence was operationalized as the quasi-causal association between girls' self-reported risk-taking and the risk-taking reported by their friends. Girls with earlier ages at menarche and who perceived themselves as more developed than peers were more susceptible to peer influence on risk-taking. However, age-standardized ratings of body changes did not moderate peer influence. This study highlights distinctions between multiple measures of pubertal timing, using an innovative synthesis of genetically informative data and peer nomination data.

  11. Placental cord insertion and birthweight discordance in twin pregnancies: results of the national prospective ESPRiT Study.

    Science.gov (United States)

    Kent, Etaoin M; Breathnach, Fionnuala M; Gillan, John E; McAuliffe, Fionnuala M; Geary, Michael P; Daly, Sean; Higgins, John R; Dornan, James; Morrison, John J; Burke, Gerard; Higgins, Shane; Carroll, Stephen; Dicker, Patrick; Manning, Fiona; Malone, Fergal D

    2011-10-01

    The purpose of this study was to evaluate the impact of noncentral placental cord insertion on birthweight discordance in twins. We performed a multicenter, prospective trial of twin pregnancies. Placental cord insertion was documented as central, marginal, or velamentous according to a defined protocol. Association of the placental cord insertion site with chorionicity, birthweight discordance, and growth restriction were assessed. Eight hundred sixteen twin pairs were evaluated; 165 pairs were monochorionic, and 651 pairs were dichorionic. Monochorionic twins had higher rates of marginal (P = .0068) and velamentous (P < .0001) placental cord insertion. Noncentral placental cord insertion was more frequent in smaller twins of discordant pairs than control pairs (29.8% vs 19.1%; P = .004). Velamentous placental cord insertion in monochorionic twins was associated significantly with birthweight discordance (odds ratio, 3.5; 95% confidence interval, 1.3-9.4) and growth restriction (odds ratio, 4; 95% confidence interval, 1.1-14.3). Noncentral placental cord insertion contributes to birthweight discordance in monochorionic twin pregnancies. Sonographic delineation of placental cord insertion may be of value in antenatal assessment of twin pregnancies. Copyright © 2011 Mosby, Inc. All rights reserved.

  12. ON THE OBSERVATION AND SIMULATION OF SOLAR CORONAL TWIN JETS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiajia; Wang, Yuming; Zhang, Quanhao [CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China, NO. 96, Jinzhai Road, Hefei, Anhui 230026 (China); Fang, Fang [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, 1234 Innovation Drive, Boulder, CO 80303 (United States); McIntosh, Scott W.; Fan, Yuhong [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2016-02-01

    We present the first observation, analysis, and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. However, the erupting process and kinetics of the twin jets appear to be different from the preceding one. Lacking detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al., and find that in the simulation a pair of twin jets form due to reconnection between the ambient open fields and a highly twisted sigmoidal magnetic flux, which is the outcome of the further evolution of the magnetic fields following the preceding blowout jet. Based on the similarity between the synthesized and observed emission, we propose this mechanism as a possible explanation for the observed twin jets. Combining our observation and simulation, we suggest that with continuous energy transport from the subsurface convection zone into the corona, solar coronal twin jets could be generated in the same fashion addressed above.

  13. On the Observation and Simulation of Solar Coronal Twin Jets

    Science.gov (United States)

    Liu, Jiajia; Fang, Fang; Wang, Yuming; McIntosh, Scott W.; Fan, Yuhong; Zhang, Quanhao

    2016-02-01

    We present the first observation, analysis, and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. However, the erupting process and kinetics of the twin jets appear to be different from the preceding one. Lacking detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al., and find that in the simulation a pair of twin jets form due to reconnection between the ambient open fields and a highly twisted sigmoidal magnetic flux, which is the outcome of the further evolution of the magnetic fields following the preceding blowout jet. Based on the similarity between the synthesized and observed emission, we propose this mechanism as a possible explanation for the observed twin jets. Combining our observation and simulation, we suggest that with continuous energy transport from the subsurface convection zone into the corona, solar coronal twin jets could be generated in the same fashion addressed above.

  14. Genetic Influences on Pulmonary Function: A Large Sample Twin Study

    DEFF Research Database (Denmark)

    Ingebrigtsen, Truls S; Thomsen, Simon F; van der Sluis, Sophie

    2011-01-01

    Heritability of forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC), and peak expiratory flow (PEF) has not been previously addressed in large twin studies. We evaluated the genetic contribution to individual differences observed in FEV(1), FVC, and PEF using data from...... the largest population-based twin study on spirometry. Specially trained lay interviewers with previous experience in spirometric measurements tested 4,314 Danish twins (individuals), 46-68 years of age, in their homes using a hand-held spirometer, and their flow-volume curves were evaluated. Modern variance...

  15. DNA Methylation Changes in the IGF1R Gene in Birth Weight Discordant Adult Monozygotic Twins

    DEFF Research Database (Denmark)

    Tsai, Pei-Chien; Van Dongen, Jenny; Tan, Qihua

    2015-01-01

    persists into adulthood. To investigate this further, we performed epigenome-wide association analyses of blood DNA methylation using Infinium HumanMethylation450 BeadChip profiles in 71 adult monozygotic (MZ) twin pairs who were extremely discordant for birth weight. A signal mapping to the IGF1R gene (cg...... were not significant. However, a meta-analysis across the four independent samples, in total 216 birth-weight discordant MZ twin pairs, showed a significant positive association between birth weight and DNA methylation differences at IGF1R (random-effects meta-analysis p = .04), and the effect...... was particularly pronounced in older twins (random-effects meta-analysis p = .008, 98 older birth-weight discordant MZ twin pairs). The results suggest that severe intra-uterine growth differences (birth weight discordance >20%) are associated with methylation changes in the IGF1R gene in adulthood, independent...

  16. Sociological and socio-psycho-historical problems of A-bomb exposed twin

    International Nuclear Information System (INIS)

    Watanabe, Shoji

    1983-01-01

    The atomic bombing of Hiroshima brought many casualities on human society, and collapsed human communities. The purpose of this study is to make mainly on pairs of monozygotic twins one of whom was exposed and the other was not, or both of whom were exposed, a general socio-psycho-historical investigations through a twin control study to find whether the bombing, which can be considered to cause major environmental changes, has had any psychological effects on the individuals. Due to the limited sample of atomic bomb exposed twins, in numbers available for study, it is necessary to have an understanding for their condions of the living and identity they have developed from the numerous mental stress they suffered, and rapid socio-cultural changes they experienced, including for changes in life from birth until the atomic bombing and aftermath of the disaster. As the result of this study, by depth interview, projective psychological research and research on socio-psycho-history of exposed twin and the nonexposed before the A-bomb and aftermath of disaster, the following were obtained: a) Although at the age of four and eight they exposed, they still keep it in clear memory of the damage and suffering in the minds. b) The damage and suffereng of the family who belonged were relatively small, the effects of their psychological sufferings continued even after these thirtyseven years. c) In the aftermath of the A-bomb disaster, the psychological bond showed strengthen through crises and following social distress. d) During the long period since the bombing, those who did not experienced A-bombing, have shown high degree of support and co-operation on their familial and social role to their counterpart. e) Even though their social or medical effects of A-bombing are relatively limited, if their spouse or close relative suffer psychological stress caused by A-bomb, they too suffer from their similar experiences. (J.P.N.)

  17. Neurodevelopmental outcome at 2 years in twin-twin transfusion syndrome survivors randomized for the Solomon trial.

    Science.gov (United States)

    van Klink, Jeanine M M; Slaghekke, Femke; Balestriero, Marina A; Scelsa, Barbara; Introvini, Paola; Rustico, Mariangela; Faiola, Stefano; Rijken, Monique; Koopman, Hendrik M; Middeldorp, Johanna M; Oepkes, Dick; Lopriore, Enrico

    2016-01-01

    The preferred treatment for twin-twin transfusion syndrome is fetoscopic laser coagulation of inter-twin vascular anastomoses on the monochorionic placenta. Severe postoperative complications can occur when inter-twin vascular anastomoses remain patent including twin-anemia polycythemia sequence or recurrent twin-twin transfusion syndrome. To minimize the occurrence of residual anastomoses, a modified laser surgery technique, the Solomon technique, was developed in which the entire vascular equator is coagulated. In the Solomon randomized controlled trial (NTR1245), the Solomon technique was associated with a significant reduction in twin-anemia polycythemia sequence and recurrence of twin-twin transfusion syndrome when compared with the standard laser surgery technique. Although a significant improvement in perinatal outcome was shown after the Solomon technique, the clinical importance should also be ascertained with long-term follow-up evaluation of the surviving children. The purpose of this study was to compare the long-term neurodevelopmental outcome in surviving children with twin-twin transfusion syndrome who were included in the Solomon randomized trial and treated with either the Solomon technique or standard laser surgery technique. Routine standardized follow-up evaluation in survivors, at least 2 years after the estimated date of delivery, was performed at 2 of the 5 centers that participated in the Solomon trial: Buzzi Hospital Milan (Italy) and Leiden University Medical Center (The Netherlands). The primary outcome of this follow-up study was survival without long-term neurodevelopmental impairment at age 2 years. Neurodevelopmental impairment was defined as cerebral palsy, cognitive and/or motor development score of neurodevelopmental impairment) was detected in 95 of 141 cases (67%) in the Solomon group and in 99 of 146 cases (68%) in the standard group (P = .92). Neurodevelopmental impairment in long-term survivors who were included for follow

  18. Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study.

    Directory of Open Access Journals (Sweden)

    Jong Chul Han

    Full Text Available Optic nerve head (ONH and surrounding structures such as β-zone peripapillary atrophy (PPA are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels.A total of 1,205 adult twins and their family members (362 monozygotic (MZ twin subjects (181 pairs, 64 dizygotic (DZ twin subjects (32 pairs, and 779 singletons from 261 families, were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods.The intraclass correlation coefficient (ICC values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively.ONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not.

  19. Risk factors for asthma in young adults: a co-twin control study

    DEFF Research Database (Denmark)

    Thomsen, SF; Ulrik, Charlotte Suppli; Kyvik, KO

    2006-01-01

    BACKGROUND: The liability to asthma is influenced both by genetic and environmental factors. The objective of this study was to identify risk factors for asthma in young adult twin pairs during an 8-year period. METHODS: From the birth cohorts 1953-1982 of the Danish Twin Registry, 6,090 twin pairs....... Pairs in which only one twin developed asthma -- discordant pairs -- were identified and conditional logistic regression was applied to detect effects of risk factors. RESULTS: A total of 126 monozygotic (MZ) and 273 dizygotic (DZ) discordant twin pairs were identified. In MZ twins hay fever (OR = 3...... and females = 0.54, 95% CI: 0.36-0.80, P = 0.002), and increasing levels of body mass index (BMI; OR per unit = 1.11, 95% CI: 1.02-1.20, P = 0.009) were significant predictors of asthma. CONCLUSIONS: Hay fever, eczema, female sex, exercise and increasing levels of BMI were risk factors for asthma in young...

  20. Late language emergence in 24-month-old twins: heritable and increased risk for late language emergence in twins.

    Science.gov (United States)

    Rice, Mabel L; Zubrick, Stephen R; Taylor, Catherine L; Gayán, Javier; Bontempo, Daniel E

    2014-06-01

    This study investigated the etiology of late language emergence (LLE) in 24-month-old twins, considering possible twinning, zygosity, gender, and heritability effects for vocabulary and grammar phenotypes. A population-based sample of 473 twin pairs participated. Multilevel modeling estimated means and variances of vocabulary and grammar phenotypes, controlling for familiality. Heritability was estimated with DeFries-Fulker regression and variance components models to determine effects of heritability, shared environment, and nonshared environment. Twins had lower average language scores than norms for single-born children, with lower average performance for monozygotic than dizygotic twins and for boys than girls, although gender and zygosity did not interact. Gender did not predict LLE. Significant heritability was detected for vocabulary (0.26) and grammar phenotypes (0.52 and 0.43 for boys and girls, respectively) in the full sample and in the sample selected for LLE (0.42 and 0.44). LLE and the appearance of Word Combinations were also significantly heritable (0.22-0.23). The findings revealed an increased likelihood of LLE in twin toddlers compared with single-born children that is modulated by zygosity and gender differences. Heritability estimates are consistent with previous research for vocabulary and add further suggestion of heritable differences in early grammar acquisition.

  1. [About twins: Epidemiological, genetic, and obstetrical aspects, specific risks, and outcome].

    Science.gov (United States)

    Tauzin, M; Felix, A; Michot, C; Dedieu, C; Aoust, L; Fortas, F; Guillier, C; Ngo, J; Wachter, P-Y; Petermann, L; Kermorvant-Duchemin, E

    2017-12-01

    The incidence of twin pregnancies has increased steadily for the last 40 years due to assisted reproductive technology and increased maternal childbearing age. Multiple pregnancies, especially monochorionic twin pregnancies, carry a high risk for the mother and the fetuses and require close follow-up. Twins are exposed to a higher risk of perinatal anoxia, in utero fetal demise, preterm birth, congenital malformations, fetal growth restriction, and vascular complications. Compared to singletons, twins are at higher risk of perinatal mortality and impaired neurodevelopmental outcome, justifying a thorough follow-up by pediatricians, including assessment and management of familial and psychosocial impact. This paper discusses the epidemiological, obstetrical, and genetic issues raised by twin pregnancies and reviews the data on the perinatal and neurological long-term outcomes of twins, as well as the psychosocial impact of multiple births on twins and their families. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Uses of the Twins UK genetic database.

    Science.gov (United States)

    Spector, Tim D

    2007-11-01

    Tim Spector is a Professor of Genetic Epidemiology at King's College London and Director of the Twin Research and Genetic Epidemiology Unit at St Thomas' Hospital, London. Professor Spector graduated from St Bartholomew's Hospital Medical School, London, in 1982. After working in General Medicine, he completed a MSc in Epidemiology, and his MD degree at the University of London in 1989. He founded the UK Twins Registry of 10,000 twins in 1993, which is one of the largest collections of genotype and phenotype information on twins worldwide, whose breadth of research has expanded to cover a wide range of common complex traits many of which were previously thought to be mainly due to aging and the environment. He has published over 350 research articles on common diseases. He has written several original articles on the genetics of a wide range of diseases and traits including back pain, acne, inflammation, obesity, memory, musical ability and sexuality. He is the principal investigator of the EU Euroclot and Treat OA study, and a partner in five others. He has written several books, focusing on osteoporosis and genetics and, in 2003, he published a popular book on genetics: Your Genes Unzipped.

  3. Thermodynamics of twinning

    International Nuclear Information System (INIS)

    Mueller, I.; Zak, G.

    1995-01-01

    The quasiplastic hysteresis occuring in shape memory alloys is associated with twinning in tension and compression, i.e. a conversion of one martensitic variant into antoher one. It shows the phenomena of internal elasticity and internal yield, heretofore studied extensively in pseudoelasticity. This paper presents experimental evidence of such phenomena and it offers partial explanation in identifying the onset of yield as an instability phenomenon due to coherency. That conjecture is motivated from a previous consideration of pseudoelasticity. (orig.)

  4. Perinatal outcome of monochorionic and dichorionic twins after spontaneous and assisted conception: a retrospective cohort study.

    Science.gov (United States)

    Hack, Karien E A; Vereycken, Marijn E M S; Torrance, Helen L; Koopman-Esseboom, Corine; Derks, Jan B

    2018-06-01

    The aim of this study was to compare pregnancy outcomes in twin pregnancies after assisted conception and spontaneous conception, according to chorionicity. Retrospective cohort study of 1305 twin pregnancies between 1995 and 2015. All spontaneous (n = 731) and assisted conception conceived (n = 574) twin pregnancies with antenatal care and delivery in University Medical Center Utrecht, the Netherlands, a tertiary obstetric care center were studied according to chorionicity. Maternal age and incidence of nulliparity were higher among the assisted conception twins. Hypertensive disorders also appeared to be more frequent in assisted conception pregnancies, which could largely be explained by the higher proportion of elderly nulliparous women in this group. Spontaneously conceived twins were born earlier than twins after assisted conception, with subsequent lower birthweights and more admissions to a neonatal intensive care unit with increased neonatal morbidity. Monochorionic twins had worse pregnancy outcomes compared with dichorionic twins, irrespective of mode of conception; monochorionic twins conceived by assisted reproduction had more neonatal morbidity (mainly respiratory distress syndrome and necrotizing enterocolitis) and late neonatal deaths compared with spontaneously conceived monochorionic twins. Spontaneously conceived twins have worse pregnancy outcome compared with twins after assisted conception, probably due to a lower incidence of monochorionicity in the assisted conception group. The already increased perinatal risks in monochorionic twins are even higher in monochorionic twins conceived after infertility treatments compared with spontaneously conceived monochorionic twins, which warrants extra attention to these high-risk pregnancies. © 2018 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).

  5. Monozygotic twins with discordant intestinal rotation

    International Nuclear Information System (INIS)

    Smith, Vance L.; Nwomeh, Benedict C.; Long, Frederick

    2006-01-01

    Previous case reports have suggested a strong concordance of intestinal malrotation among identical twins. This has led to the recommendation that the asymptomatic twin undergo screening when malrotation is discovered in the identical sibling. We present a case of monozygotic twins in which one twin presented with intestinal malrotation with midgut volvulus while the other twin was found to have normal gastrointestinal anatomy. (orig.)

  6. Monozygotic twins with discordant intestinal rotation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Vance L.; Nwomeh, Benedict C. [Ohio State University College of Medicine and Public Health, Department of Pediatric Surgery, Columbus Children' s Hospital, Columbus, OH (United States); Long, Frederick [Ohio State University College of Medicine and Public Health, Department of Radiology, Columbus Children' s Hospital, Columbus, OH (United States)

    2006-04-15

    Previous case reports have suggested a strong concordance of intestinal malrotation among identical twins. This has led to the recommendation that the asymptomatic twin undergo screening when malrotation is discovered in the identical sibling. We present a case of monozygotic twins in which one twin presented with intestinal malrotation with midgut volvulus while the other twin was found to have normal gastrointestinal anatomy. (orig.)

  7. The accuracy of self-reported history of seizures in Danish, Norwegian and U.S. twins

    DEFF Research Database (Denmark)

    Corey, Linda A; Kjeldsen, Marianne J; Solaas, Marit H

    2009-01-01

    . The accuracy of these reports was assessed. Self-reported epilepsy was verified in 81.9% of twins overall (86.1% (DTR), 75.6% (NTR) and 80.7% (MATR)). However, when both pair members reported a history of epilepsy in the affected pair member, epilepsy was verified in >90% of cases. Among MATR twins...... of this approach in identifying true cases. Information on history of seizures obtained by questionnaire from members of 47,626 twin pairs included in the Mid-Atlantic (MATR), Danish (DTR) and Norwegian (NTR) Twin Registries was verified using medical records and detailed clinical and family interviews...... with a verified history of epilepsy, 21.5% reported other seizures but not epilepsy and 18.5% of verified Norwegian epilepsy cases reported no history of epilepsy themselves and were identified only through their co-twin. The results of this study indicate that the accuracy of self-reported epilepsy and febrile...

  8. Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins.

    Science.gov (United States)

    Cohen-Cline, Hannah; Lau, Richard; Moudon, Anne V; Turkheimer, Eric; Duncan, Glen E

    2015-08-01

    Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors.

  9. Increased frequency of micronuclei in adults with a history of childhood sexual abuse: a discordant monozygotic twin study.

    Directory of Open Access Journals (Sweden)

    Timothy P York

    Full Text Available Childhood sexual abuse (CSA is a traumatic life event associated with an increased lifetime risk for psychopathology/morbidity. The long-term biological consequences of CSA-elicited stress on chromosomal stability in adults are unknown. The primary aim of this study was to determine if the rate of acquired chromosomal changes, measured using the cytokinesis-block micronucleus assay on stimulated peripheral blood lymphocytes, differs in adult female monozygotic twins discordant for CSA.Monozygotic twin pairs discordant for CSA were identified from a larger population-based sample of female adult twins for whom the experience of CSA was assessed by self-report (51 individuals including a reference sample. Micronuclei (MN contain chromatin from structurally normal or abnormal chromosomes that are excluded from the daughter nuclei during cell division and serve as a biomarker to assess acquired chromosomal instability.Female twins exposed to CSA exhibited a 1.63-fold average increase in their frequency of MN compared to their nonexposed genetically identical cotwins (Paired t-test, t₁₆ = 2.65, P = 0.017. No additional effects of familial factors were detected after controlling for the effect of CSA exposure. A significant interaction between CSA history and age was observed, suggesting that the biological effects of CSA on MN formation may be cumulative.These data support a direct link between CSA exposure and MN formation measured in adults that is not attributable to genetic or environmental factors shared by siblings. Further research is warranted to understand the biological basis for the observed increase in acquired chromosomal findings in people exposed to CSA and to determine if acquired somatic chromosomal abnormalities/somatic clonal mosaicism might mediate the adult pathology associated with CSA.

  10. Genetic influences on musical specialization: a twin study on choice of instrument and music genre.

    Science.gov (United States)

    Mosing, Miriam A; Ullén, Fredrik

    2018-05-09

    Though several studies show that genetic factors influence individual differences in musical engagement, aptitude, and achievement, no study to date has investigated whether specialization among musically active individuals in terms of choice of instrument and genre is heritable. Using a large twin cohort, we explored whether individual differences in instrument choice, instrument category, and the type of music individuals engage in can entirely be explained by the environment or are partly due to genetic influences. About 10,000 Swedish twins answered an extensive questionnaire about music-related traits, including information on the instrument and genre they played. Of those, 1259 same-sex twin pairs reported to either play an instrument or sing. We calculated the odds ratios (ORs) for concordance in music choices (if both twins played) comparing identical and nonidentical twin pairs, with significant ORs indicating that identical twins are more likely to engage in the same type of music-related behavior than are nonidentical twins. The results showed that for almost all music-related variables, the odds were significantly higher for identical twins to play the same musical instrument or music genre, suggesting significant genetic influences on such music specialization. Possible interpretations and implications of the findings are discussed. © 2018 New York Academy of Sciences.

  11. The Heritability of Insomnia Progression during Childhood/Adolescence: Results from a Longitudinal Twin Study

    Science.gov (United States)

    Barclay, Nicola L.; Gehrman, Philip R.; Gregory, Alice M.; Eaves, Lindon J.; Silberg, Judy L.

    2015-01-01

    Study Objectives: To determine prevalence and heritability of insomnia during middle/late childhood and adolescence; examine longitudinal associations in insomnia over time; and assess the extent to which genetic and environmental factors on insomnia remain stable, or whether new factors come into play, across this developmental period. Design: Longitudinal twin study. Setting: Academic medical center. Patients or Participants: There were 739 complete monozygotic twin pairs (52%) and 672 complete dizygotic twin pairs (48%) initially enrolled and were followed up at three additional time points (waves). Mode ages at each wave were 8, 10, 14, and 15 y (ages ranged from 8–18 y). Interventions: None. Measurements and Results: Clinical ratings of insomnia symptoms were assessed using the Child and Adolescent Psychiatric Assessment (CAPA) by trained clinicians, and rated according to Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition—Revised criteria for presence of “clinically significant insomnia,” over four sequential waves. Insomnia symptoms were prevalent but significantly decreased across the four waves (ranging from 16.6% to 31.2%). “Clinically significant insomnia” was moderately heritable at all waves (h2 range = 14% to 38%), and the remaining source of variance was the nonshared environment. Multivariate models indicated that genetic influences at wave 1 contributed to insomnia at all subsequent waves, and that new genetic influences came into play at wave 2, which further contributed to stability of symptoms. Nonshared environmental influences were time-specific. Conclusion: Insomnia is prevalent in childhood and adolescence, and is moderately heritable. The progression of insomnia across this developmental time period is influenced by stable as well as new genetic factors that come into play at wave 2 (modal age 10 y). Molecular genetic studies should now identify genes related to insomnia progression during childhood and

  12. The ethics of separating conjoined twins: two arguments against.

    Science.gov (United States)

    Kallberg, Luke

    2018-02-01

    I argue that the separation of conjoined twins in infancy or early childhood is unethical (rare exceptions aside). Cases may be divided into three types: both twins suffer from lethal abnormalities, only one twin has a lethal abnormality, or neither twin does. In the first kind of case, there is no reason to separate, since both twins will die regardless of treatment. In the third kind of case, I argue that separation at an early age is unethical because the twins are likely to achieve an irreplaceably good quality of life-the goods of conjoinment-that separation takes away. Evaluation of this possibility requires maturation past early childhood. Regarding the second type, I point out that with conceivable but unrecorded exceptions, these cases will consistently involve sacrifice separation. I present an argument that sacrifice separation is unethical, but in some cases a moral dilemma may exist in which separation and refraining from separation are both unethical. Perhaps in such cases a decision can be made on non-moral grounds; however, the possibility of such a decision serves not to mitigate but to underscore the fact that the separation is unethical. My conclusion, which applies to all three types of cases, is that it is unethical to separate conjoined twins before their developing personalities give some reliable indication as to whether they desire separation and whether they will achieve those goods of conjoinment.

  13. Chronic Idiopathic Neutrophilia in Two Twins

    Directory of Open Access Journals (Sweden)

    Roberto Miniero

    2014-01-01

    Full Text Available Neutrophilia in adults refers to an alteration in the total number of blood neutrophils that is in excess of about 7500 cells/μL. This definition is restrictive in childhood as neutrophil count is age-dependent. Chronic Idiopathic Neutrophilia (CIN refers to a condition that persists for many years in individuals who appear otherwise healthy. CIN is rarely mentioned in scientific literature and in academic books of hematology; only few words are dedicated to this topic. We report a case study of two twins with CIN followed from the first year of life to 24 years of age. To the best of our knowledge this is the first case report of two twins with CIN followed through a long period of time. We believe that our observation may contribute to better understand and characterize this hematologic abnormality.

  14. Illustrations of the twin paradox

    International Nuclear Information System (INIS)

    Rebhan, E.

    1985-01-01

    In order to provide a more intuitive understanding of the twin paradox, several illustrations of this are presented. In one of these, each of the twins is equipped with a lamp whose monochromatic light can be observed by the other. In other illustrations the travelling twin uses an Einstein train instead of a space ship, all the cars of the train and all stations along the route of the train being equipped with clocks. (author)

  15. Sleep Duration and Area-Level Deprivation in Twins.

    Science.gov (United States)

    Watson, Nathaniel F; Horn, Erin; Duncan, Glen E; Buchwald, Dedra; Vitiello, Michael V; Turkheimer, Eric

    2016-01-01

    We used quantitative genetic models to assess whether area-level deprivation as indicated by the Singh Index predicts shorter sleep duration and modifies its underlying genetic and environmental contributions. Participants were 4,218 adult twin pairs (2,377 monozygotic and 1,841 dizygotic) from the University of Washington Twin Registry. Participants self-reported habitual sleep duration. The Singh Index was determined by linking geocoding addresses to 17 indicators at the census-tract level using data from Census of Washington State and Census Tract Cartographic Boundary Files from 2000 and 2010. Data were analyzed using univariate and bivariate genetic decomposition and quantitative genetic interaction models that assessed A (additive genetics), C (common environment), and E (unique environment) main effects of the Singh Index on sleep duration and allowed the magnitude of residual ACE variance components in sleep duration to vary with the Index. The sample had a mean age of 38.2 y (standard deviation [SD] = 18), and was predominantly female (62%) and Caucasian (91%). Mean sleep duration was 7.38 h (SD = 1.20) and the mean Singh Index score was 0.00 (SD = 0.89). The heritability of sleep duration was 39% and the Singh Index was 12%. The uncontrolled phenotypic regression of sleep duration on the Singh Index showed a significant negative relationship between area-level deprivation and sleep length (b = -0.080, P sleep duration. For the quasi-causal bivariate model, there was a significant main effect of E (b(0E) = -0.063; standard error [SE] = 0.30; P sleep duration were significant for both A (b(0Au) = 0.734; SE = 0.020; P deprivation has a quasi-causal association with sleep duration, with greater deprivation being related to shorter sleep. As area-level deprivation increases, unique genetic and nonshared environmental residual variance in sleep duration increases. © 2016 Associated Professional Sleep Societies, LLC.

  16. Dancing Twins: Stellar Hierarchies That Formed Sequentially?

    Science.gov (United States)

    Tokovinin, Andrei

    2018-04-01

    This paper draws attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer component. Such systems could be formed either sequentially (inside-out) by disk fragmentation with subsequent accretion and migration, or by a cascade hierarchical fragmentation of a rotating cloud. Orbits of the outer and inner subsystems are computed or updated in four such hierarchies: LHS 1070 (GJ 2005, periods 77.6 and 17.25 years), HIP 9497 (80 and 14.4 years), HIP 25240 (1200 and 47.0 years), and HIP 78842 (131 and 10.5 years).

  17. Language Development of Three- to Twelve-Year-Old Twins Compared to Singletons.

    Science.gov (United States)

    Dʼhaeseleer, Evelien; Geenens, Eline; Parmentier, Sarah; Corthals, Paul; Van Lierde, Kristiane

    2016-01-01

    The language development of twins tends to lag behind in comparison to that of singletons. The purpose of this study was to compare expressive and receptive language skills of 3- to 12-year-old twins with singletons. Secondly, correlations between language differences between twins and singletons and age were investigated. Twenty-four twins with a mean age of 5.1 years participated in the study. The control group consisted of 24 singletons who were matched for gender and age. Language development was investigated using the Clinical Evaluation of Language Fundamentals. Twins scored significantly lower for expressive and receptive language skills compared to singletons. Even when excluding preterm-born children, twins still scored significantly lower for expressive language skills. There was no correlation between age and language differences between twins and their matched singletons. Twins score lower for expressive and receptive language skills compared to singletons, and preterm birth cannot be regarded as the main cause for the language delay. The language delay in twins is rather mild but does not seem to decrease with increasing age. © 2016 S. Karger AG, Basel.

  18. Changes in genetic and environmental influences on disordered eating between early and late adolescence: a longitudinal twin study.

    Science.gov (United States)

    Fairweather-Schmidt, A K; Wade, T D

    2015-11-01

    We investigated the genetic and environmental contributions to disordered eating (DE) between early and late adolescence in order to determine whether different sources of heritability and environmental risk contributed to these peak times of emergence of eating disorders. Adolescent female twins from the Australian Twin Registry were interviewed over the telephone with the Eating Disorder Examination (EDE). Data were collected at 12-15 and 16-19 years (wave 1: N = 699, 351 pairs; wave 3: N = 499, 247 pairs). Assessments also involved self-report measures related to negative life events and weight-related peer teasing. Unstandardized estimates from the bivariate Cholesky decomposition model showed both genetic influences and non-shared environmental influences increased over adolescence, but shared environmental influences decreased. While non-shared environmental sources active at ages 12-15 years continued to contribute at 16-19 years, new sources of both additive genetic and non-shared environmental risk were introduced at ages 16-19 years. Weight-related peer teasing in early-mid adolescence predicted increases of DE in later adolescence, while negative life events did not. Two-thirds of the heritable influence contributing to DE in late adolescence was unique to this age group. During late adolescence independent sources of genetic risk, as well as environmental influences are likely to be related in part to peer teasing, appear key antecedents in growth of DE.

  19. Twin correlations of telomere length metrics

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Dalgård, Christine; Möller, Sören

    2015-01-01

    variation among adults. A number of studies have estimated the heritability of LTL, but none has assessed the heritability of age-dependent LTL attrition. METHODS: We examined the heritability of LTL dynamics based on a longitudinal evaluation (an average follow-up of 12 years) in 355 monozygotic and 297...... dizygotic same-sex twins (aged 19-64 years at baseline). RESULTS: Heritability of LTL at baseline was estimated at 64% (95% CI 39% to 83%) with 22% (95% CI 6% to 49%) of shared environmental effects. Heritability of age-dependent LTL attrition rate was estimated at 28% (95% CI 16% to 44%). Individually...

  20. Epigenetic predictor of age.

    Directory of Open Access Journals (Sweden)

    Sven Bocklandt

    Full Text Available From the moment of conception, we begin to age. A decay of cellular structures, gene regulation, and DNA sequence ages cells and organisms. DNA methylation patterns change with increasing age and contribute to age related disease. Here we identify 88 sites in or near 80 genes for which the degree of cytosine methylation is significantly correlated with age in saliva of 34 male identical twin pairs between 21 and 55 years of age. Furthermore, we validated sites in the promoters of three genes and replicated our results in a general population sample of 31 males and 29 females between 18 and 70 years of age. The methylation of three sites--in the promoters of the EDARADD, TOM1L1, and NPTX2 genes--is linear with age over a range of five decades. Using just two cytosines from these loci, we built a regression model that explained 73% of the variance in age, and is able to predict the age of an individual with an average accuracy of 5.2 years. In forensic science, such a model could estimate the age of a person, based on a biological sample alone. Furthermore, a measurement of relevant sites in the genome could be a tool in routine medical screening to predict the risk of age-related diseases and to tailor interventions based on the epigenetic bio-age instead of the chronological age.

  1. Sleep Duration and Area-Level Deprivation in Twins

    Science.gov (United States)

    Watson, Nathaniel F.; Horn, Erin; Duncan, Glen E.; Buchwald, Dedra; Vitiello, Michael V.; Turkheimer, Eric

    2016-01-01

    Study Objectives: We used quantitative genetic models to assess whether area-level deprivation as indicated by the Singh Index predicts shorter sleep duration and modifies its underlying genetic and environmental contributions. Methods: Participants were 4,218 adult twin pairs (2,377 monozygotic and 1,841 dizygotic) from the University of Washington Twin Registry. Participants self-reported habitual sleep duration. The Singh Index was determined by linking geocoding addresses to 17 indicators at the census-tract level using data from Census of Washington State and Census Tract Cartographic Boundary Files from 2000 and 2010. Data were analyzed using univariate and bivariate genetic decomposition and quantitative genetic interaction models that assessed A (additive genetics), C (common environment), and E (unique environment) main effects of the Singh Index on sleep duration and allowed the magnitude of residual ACE variance components in sleep duration to vary with the Index. Results: The sample had a mean age of 38.2 y (standard deviation [SD] = 18), and was predominantly female (62%) and Caucasian (91%). Mean sleep duration was 7.38 h (SD = 1.20) and the mean Singh Index score was 0.00 (SD = 0.89). The heritability of sleep duration was 39% and the Singh Index was 12%. The uncontrolled phenotypic regression of sleep duration on the Singh Index showed a significant negative relationship between area-level deprivation and sleep length (b = −0.080, P sleep duration. For the quasi-causal bivariate model, there was a significant main effect of E (b0E = −0.063; standard error [SE] = 0.30; P sleep duration were significant for both A (b0Au = 0.734; SE = 0.020; P sleep duration, with greater deprivation being related to shorter sleep. As area-level deprivation increases, unique genetic and nonshared environmental residual variance in sleep duration increases. Citation: Watson NF, Horn E, Duncan GE, Buchwald D, Vitiello MV, Turkheimer E. Sleep duration and area

  2. Comparative examinations on the activity and variant selection of twinning during tension and compression of magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dejia [College of Materials Science and Engineering, Chongqing University, Chongqing (China); School of Mechatronics Engineering, East China Jiaotong University, Nanchang (China); Xin, Renlong, E-mail: rlxin@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing (China); State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing (China); Hongni, Yu; Liu, Zhe; Zheng, Xuan [College of Materials Science and Engineering, Chongqing University, Chongqing (China); Liu, Qing, E-mail: qingliu@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing (China)

    2016-03-21

    In the present study, an Mg weld with β-type fiber texture was produced by friction stir welding (FSW) and then was subjected to tension and compression along the transverse direction (TD). The deformed microstructure by 5% strain was examined in various regions of the Mg weld by electron backscatter diffraction (EBSD) technique. It was found that profuse twinning was activated in stir zone (SZ) -side after tension and in SZ-center and crown zone (CZ) -center after compression due to the presence of relatively large Schmid factor (SF). However, a few twins (2–3%) were also observed in SZ-center after tension and in SZ-side after compression. In this case, the twins have very small and even negative SF. For the twins with large SF, they were likely connected at grain boundaries forming twin pairs, while for those with small or negative SF, they were mostly confined within grains. For connected twins, most of the active variants have favorable SF and geometric compatibility factor (m′). However, the distributions of SF and m′ are different between the twins formed in compression and tension. For isolated twins, the adjacent grains connected with the twins were generally in favorable orientation for basal slip, and the selection of twin variants was likely affected by m′ between the most favorable basal slip and the twins.

  3. Spatiotemporal configuration dependent pairing of nerve events in dark-adapted human vision

    NARCIS (Netherlands)

    Bouman, M.A.

    2002-01-01

    In the model presented here, in the dark any single quantum absorption in a rod or cone produces a subliminal excitation. Subliminal excitations from both halves of a twin unit pair in the retina for the perception of light from the stimulus. A twin unit contains either two red or two green cones.

  4. Outcomes of preterm premature rupture of membranes in twin pregnancies.

    Science.gov (United States)

    Trentacoste, Stephanie V; Jean-Pierre, Claudel; Baergen, Rebecca; Chasen, Stephen T

    2008-08-01

    To describe outcomes in twin pregnancies with preterm premature rupture of membranes (PPROM). Dichorionic twin pregnancies complicated by PPROM at premature rupture of membranes (PROM), latency from PROM to delivery, and infection were examined. In 49 twin pregnancies, the median gestational age at PROM was 31 weeks with a median latency between PROM and delivery of 0 days (interquartile range 0-6). Latency intervals of >or=2 and >or=7 days were achieved by 40.8% and 22.4%, respectively. PPROM at or= 2 days (70.6% vs. 25.0%) and >or=7 days (47.1% vs. 9.4%). There was a significant relationship between latency and clinical and histologic signs of infection. After 30 weeks, most twin pregnancies with PPROM delivered within 2 days. Infection appears to be a consequence rather than a cause of PPROM in most cases.

  5. Infertility, infertility treatment and twinning: the Danish National Birth Cohort

    DEFF Research Database (Denmark)

    Zhu, Jin Liang; Basso, Olga; Obel, Carsten

    2007-01-01

    BACKGROUND: We have previously observed that an increasing time to pregnancy (TTP) is associated with a reduced frequency of twin deliveries in couples not receiving infertility treatment. By using updated information, we assessed the frequencies of dizygotic (DZ) and monozygotic (MZ) twin...... deliveries as a function of infertility (TTP > 12 months), as well as infertility treatment. METHODS: From the Danish National Birth Cohort (1997-2003), we identified 51 730 fertile couples with TTP 12 months and 5163 infertile couples who conceived after treatment. Information on zygosity, available...... for part of the cohort (1997-2000), was based on standardized questions on the similarities between the twins at the age of 3-5 years. RESULTS: Compared with fertile couples, the frequency of DZ twin deliveries was lower for infertile couples conceiving naturally (odds ratio 0.4, 95% confidence interval 0...

  6. Genetic and developmental factors in spontaneous selective attention: a study of normal twins.

    Science.gov (United States)

    Myles-Worsley, M; Coon, H

    1997-08-08

    The Spontaneous Selective Attention Task (SSAT) is a visual word identification task designed to measure the type of selective attention that occurs spontaneously when there are multiple stimuli, all potentially relevant, and insufficient time to process each of them fully. These are conditions which are common in everyday life. SSAT performance is measured by word identification accuracy, first under a baseline divided attention condition with no predictability, then under a selective attention condition with partial predictability introduced via word repetition. Accuracy to identify novel words in the upper location which becomes partially predictable (P words) vs. the lower location which remains non-predictable (N words) can be used to calculate a baseline performance index and a P/N ratio measure of selective attention. The SSAT has been shown to identify an attentional abnormality that may be useful in the development of an attentional endophenotype for family-genetic studies of schizophrenia. This study examined age and genetic effects on SSAT performance in normal children in order to evaluate whether the SSAT has the potential to qualify as a candidate endophenotype for schizophrenia in studies of at-risk children. A total of 59 monozygotic twin pairs and 33 same-sex dizygotic twin pairs ranging from 10 to 18 years of age were tested on the SSAT, a Continuous Performance Test. (CPT), a Span of Apprehension Test (SPAN) and a full-scale IQ test. Baseline performance on the SSAT, which was correlated with verbal IQ and SPAN performance, improved with age but showed no significant heritability. The P/N selectivity ratio was stable over the 10-18-year age range, was not significantly correlated with IQ, CPT, or SPAN performance, and its heritability was estimated to be 0.41. These findings suggest that the P/N selectivity ratio measured by the SSAT may be useful as a vulnerability marker in studies of children born into families segregating schizophrenia.

  7. Holographic twin Higgs model.

    Science.gov (United States)

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  8. Holographic Twin Higgs Model

    Science.gov (United States)

    Geller, Michael; Telem, Ofri

    2015-05-01

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at mKK , naturally allowing for mKK beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  9. A lateral cephalometric study of craniofacial variation in Korean child twins

    International Nuclear Information System (INIS)

    Lee, Sang Rae; You, Dong Soo

    1974-01-01

    A study was performed to investigate the degree of similarities and differences in components of craniofacial complex between Korean twins and normal children by lateral cephalometric analysis. Dimensions of S-N, S-Ba, N-Ba, Go-Me, Ar-Go and Ar-Me were plotted against linear measurement and angles of N-S-Ba and gonial against angular measurement in twins and control groups. The lateral cephalograms of twin were composed of 88 twins aged from 7 to 12:44 males aged 10.65 and 44 females aged 9. 55, while those of 50 normalities were composed of 25 male and 25 female aged 10.9 respectively. In order to analyze growth proportion and sexual differences, twins were divided into 3 groups according to two year age intervals and the author compared male with female in 3 groups. For the purpose of observing similarities and differences in twins and normalities by sex, total twins were compared with normalities. The obtained results were as follows: 1. There was no difference in craniofacial complex between twins and normalities. 2. In general, the measurements of male were larger than those of female in both twins and normalities, but there were no statistical significances of sexual differences in both groups. 3. The growth proportion of mandible by aging was larger than that of face in twins. 4. The growth pattern of gonial angle showed slight reducing tendency in twin by aging. 5. There was little difference in the growth proportion of both male and female.

  10. A lateral cephalometric study of craniofacial variation in Korean child twins

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Rae; You, Dong Soo [College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1974-11-15

    A study was performed to investigate the degree of similarities and differences in components of craniofacial complex between Korean twins and normal children by lateral cephalometric analysis. Dimensions of S-N, S-Ba, N-Ba, Go-Me, Ar-Go and Ar-Me were plotted against linear measurement and angles of N-S-Ba and gonial against angular measurement in twins and control groups. The lateral cephalograms of twin were composed of 88 twins aged from 7 to 12:44 males aged 10.65 and 44 females aged 9. 55, while those of 50 normalities were composed of 25 male and 25 female aged 10.9 respectively. In order to analyze growth proportion and sexual differences, twins were divided into 3 groups according to two year age intervals and the author compared male with female in 3 groups. For the purpose of observing similarities and differences in twins and normalities by sex, total twins were compared with normalities. The obtained results were as follows: 1. There was no difference in craniofacial complex between twins and normalities. 2. In general, the measurements of male were larger than those of female in both twins and normalities, but there were no statistical significances of sexual differences in both groups. 3. The growth proportion of mandible by aging was larger than that of face in twins. 4. The growth pattern of gonial angle showed slight reducing tendency in twin by aging. 5. There was little difference in the growth proportion of both male and female.

  11. Voice similarity in identical twins.

    Science.gov (United States)

    Van Gysel, W D; Vercammen, J; Debruyne, F

    2001-01-01

    If people are asked to discriminate visually the two individuals of a monozygotic twin (MT), they mostly get into trouble. Does this problem also exist when listening to twin voices? Twenty female and 10 male MT voices were randomly assembled with one "strange" voice to get voice trios. The listeners (10 female students in Speech and Language Pathology) were asked to label the twins (voices 1-2, 1-3 or 2-3) in two conditions: two standard sentences read aloud and a 2.5-second midsection of a sustained /a/. The proportion correctly labelled twins was for female voices 82% and 63% and for male voices 74% and 52% for the sentences and the sustained /a/ respectively, both being significantly greater than chance (33%). The acoustic analysis revealed a high intra-twin correlation for the speaking fundamental frequency (SFF) of the sentences and the fundamental frequency (F0) of the sustained /a/. So the voice pitch could have been a useful characteristic in the perceptual identification of the twins. We conclude that there is a greater perceptual resemblance between the voices of identical twins than between voices without genetic relationship. The identification however is not perfect. The voice pitch possibly contributes to the correct twin identifications.

  12. Twin Studies of Atopic Dermatitis

    DEFF Research Database (Denmark)

    Elmose, Camilla; Thomsen, Simon Francis

    2015-01-01

    Aim. The aim of this study was to conduct a systematic review of population-based twin studies of (a) the concordance and heritability of AD and (b) the relationship between AD and asthma and, furthermore, to reinterpret findings from previous twin studies in the light of the emerging knowledge a...

  13. Hypertensive disorders in twin pregnancy

    NARCIS (Netherlands)

    J.G. Santema (Job); E. Koppelaar (Elin); H.C.S. Wallenburg (Henk)

    1995-01-01

    textabstractObjective: To compare the incidence and severity of pregnancy-induced hypertensive disorders in twin pregnancy and in singleton gestation. Study design: Case-control study in the setting of a University Hospital. Each pregnancy of a consecutive series of 187 twin pregnancies attending

  14. Ferrobielastic twinning in irradiated quartz

    International Nuclear Information System (INIS)

    Shiau, S.M.

    1986-01-01

    Cultured quartz is usually free from electrical twinning; however, it may occur if the seed crystal is twinned or if undue applied forces are exerted on the crystal. Ferrobielastic twinning was studied optically (photoelastic effect) and electrically (piezoelectric effect). At room temperature, twins were perceptible at stresses of about 2.l5 x 10 8 N/m 2 , and crystals switched from their original states to the alternative twin states at stresses about 5.0 x 10 8 N/m 2 (called coercive stress). The decrease in coercive stress with increasing temperature was observed, and these coercive stresses become very low as temperatures reach to 300 0 C. The effects of irradiation on the twinning in quartz were also studied. The presence of defects produced by irradiation was utilized to pin the domain wall motion. Both neutrons and gamma rays were employed. The stress required to nucleate an appreciable volume of twins is about twice as high for irradiated crystals than for those unirradiated. This result demonstrated that the irradiated crystals can tolerate higher stresses. However, the coercive stress for complete switch-over was not much different for irradiated and unirradiated crystals. It appears that the defects caused by irradiation eliminate the initial twinning events but do not affect switch-over

  15. Genetic and Environmental Influences on Motor Function: A Magnetoencephalographic Study of Twins

    OpenAIRE

    Araki, Toshihiko; Hirata, Masayuki; Sugata, Hisato; Yanagisawa, Takufumi; Onishi, Mai; Watanabe, Yoshiyuki; Omura, Kayoko; Honda, Chika; Hayakawa, Kazuo; Yorifuji, Shiro

    2014-01-01

    To investigate the effect of genetic and environmental influences on cerebral motor function, we determined similarities and differences of movement-related cortical fields (MRCFs) in middle-aged and elderly monozygotic (MZ) twins. MRCFs were measured using a 160-channel magnetoencephalogram system when MZ twins were instructed to repeat lifting of the right index finger. We compared latency, amplitude, dipole location, and dipole intensity of movement-evoked field 1 (MEF1) between 16 MZ twin...

  16. Sleep Duration, Mortality, and Heredity-A Prospective Twin Study.

    Science.gov (United States)

    Åkerstedt, Torbjörn; Narusyte, Jurgita; Alexanderson, Kristina; Svedberg, Pia

    2017-10-01

    A number of studies have shown a U-shaped association between sleep duration and mortality. Since sleep duration is partly genetically determined, it seems likely that its association with mortality is also genetically influenced. The purpose of the present study was to investigate the influence on heredity on the association between sleep duration and mortality. We used a cohort of 14267 twins from the Swedish Twin Registry. A Cox proportional hazards regression analysis, adjusted for a number of covariates, confirmed a clear U shape with a hazard ratio (HR) = 1.34 and 95% confidence interval (CI) = 1.15-1.57 for a sleep duration of ≤6.5 hours and HR = 1.18 (CI = 1.07-1.30) for sleep of ≥9.5 hours. Reference value was 7.0 hours. A co-twin analysis of 1942 twins discordant on mortality showed a HR = 2.66 (CI = 1.17-6.04) for long (≥9.5 hours) sleep in monzygotic twins and an HR = 0.66 (CI = 0.20-2.14) for short (sleep. In dizygotic twins, no association was significant. The heritability for mortality was 28% for the whole group, while it was 86% for short sleepers and 42% for long sleepers. Thus, the link with mortality for long sleep appears to be more due to environmental factors than to heredity, while heritability dominates among short sleepers. We found that both long and short sleep were associated with higher total mortality, that the difference in mortality within twin pairs is associated with long sleep, and that short sleep has a higher heritability for mortality, while long sleep is associated with more environmental influences on mortality. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  17. Twin studies as a model for exploring the aetiology of autoimmune thyroid disease

    DEFF Research Database (Denmark)

    Brix, Thomas Heiberg; Hegedüs, Laszlo

    2012-01-01

    Twins are an important resource for evaluating the relative contribution of genetic and environmental factors in determining a phenotype. During the last decades, a number of twin studies have investigated the aetiology of several phenotypes related to thyroid autoimmunity. Taken together, these ....... Future twin studies should incorporate information on genetic, epigenetic and environmental variation thereby enhancing our ability to quantify the precise effect of specific risk factors......., and biometric twin modelling shows that approximately 75% of the total phenotypic variance in AITD is because of genetic effects. On the other hand, the lack of complete concordance in MZ twin pairs is proof of environmental and/or epigenetic factors also playing an important role. The impact of environmental...

  18. Co-bedding in neonatal nursery for promoting growth and neurodevelopment in stable preterm twins.

    Science.gov (United States)

    Lai, Nai Ming; Foong, Siew Cheng; Foong, Wai Cheng; Tan, Kenneth

    2016-04-14

    The increased birth rate of twins during recent decades and the improved prognosis of preterm infants have resulted in the need to explore measures that could optimize their growth and neurodevelopmental outcomes. It has been postulated that co-bedding simulates twins' intrauterine experiences in which co-regulatory behaviors between them are observed. These behaviors are proposed to benefit twins by reducing their stress, which may promote growth and development. However, in practice, uncertainty surrounds the benefit-risk profile of co-bedding. We aimed to assess the effectiveness of co-bedding compared with separate (individual) care for stable preterm twins in the neonatal nursery in promoting growth and neurodevelopment and reducing short- and long-term morbidities, and to determine whether co-bedding is associated with significant adverse effects.As secondary objectives, we sought to evaluate effects of co-bedding via the following subgroup analyses: twin pairs with different weight ranges (very low birth weight [VLBW] growth discordance at birth, preterm versus borderline preterm twins, twins co-bedded in incubator versus cot at study entry, and twins randomized by twin pair versus neonatal unit. We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). We used keywords and medical subject headings (MeSH) to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2), MEDLINE (via PubMed), EMBASE (hosted by EBSCOHOST), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and references cited in our short-listed articles, up to February 29, 2016. We included randomized controlled trials with randomization by twin pair and/or by neonatal unit. We excluded cross-over studies. We extracted data using standard methods of the CNRG. Two review authors independently assessed the relevance and risk of bias of retrieved records. We contacted the authors of included studies to request important

  19. Genetic and environmental effects on body mass index from infancy to the onset of adulthood: an individual-based pooled analysis of 45 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) study.

    Science.gov (United States)

    Silventoinen, Karri; Jelenkovic, Aline; Sund, Reijo; Hur, Yoon-Mi; Yokoyama, Yoshie; Honda, Chika; Hjelmborg, Jacob vB; Möller, Sören; Ooki, Syuichi; Aaltonen, Sari; Ji, Fuling; Ning, Feng; Pang, Zengchang; Rebato, Esther; Busjahn, Andreas; Kandler, Christian; Saudino, Kimberly J; Jang, Kerry L; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Gao, Wenjing; Yu, Canqing; Li, Liming; Corley, Robin P; Huibregtse, Brooke M; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth Jf; Heikkilä, Kauko; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; He, Mingguang; Ding, Xiaohu; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Tarnoki, Adam D; Tarnoki, David L; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Burt, S Alexandra; Klump, Kelly L; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Gatz, Margaret; Butler, David A; Bartels, Meike; van Beijsterveldt, Toos Cem; Craig, Jeffrey M; Saffery, Richard; Freitas, Duarte L; Maia, José Antonio; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Chong, Youngsook; Swan, Gary E; Krasnow, Ruth; Magnusson, Patrik Ke; Pedersen, Nancy L; Tynelius, Per; Lichtenstein, Paul; Haworth, Claire Ma; Plomin, Robert; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Harden, K Paige; Tucker-Drob, Elliot M; Öncel, Sevgi Y; Aliev, Fazil; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Baker, Laura A; Tuvblad, Catherine; Duncan, Glen E; Buchwald, Dedra; Willemsen, Gonneke; Rasmussen, Finn; Goldberg, Jack H; Sørensen, Thorkild Ia; Boomsma, Dorret I; Kaprio, Jaakko

    2016-08-01

    Both genetic and environmental factors are known to affect body mass index (BMI), but detailed understanding of how their effects differ during childhood and adolescence is lacking. We analyzed the genetic and environmental contributions to BMI variation from infancy to early adulthood and the ways they differ by sex and geographic regions representing high (North America and Australia), moderate (Europe), and low levels (East Asia) of obesogenic environments. Data were available for 87,782 complete twin pairs from 0.5 to 19.5 y of age from 45 cohorts. Analyses were based on 383,092 BMI measurements. Variation in BMI was decomposed into genetic and environmental components through genetic structural equation modeling. The variance of BMI increased from 5 y of age along with increasing mean BMI. The proportion of BMI variation explained by additive genetic factors was lowest at 4 y of age in boys (a(2) = 0.42) and girls (a(2) = 0.41) and then generally increased to 0.75 in both sexes at 19 y of age. This was because of a stronger influence of environmental factors shared by co-twins in midchildhood. After 15 y of age, the effect of shared environment was not observed. The sex-specific expression of genetic factors was seen in infancy but was most prominent at 13 y of age and older. The variance of BMI was highest in North America and Australia and lowest in East Asia, but the relative proportion of genetic variation to total variation remained roughly similar across different regions. Environmental factors shared by co-twins affect BMI in childhood, but little evidence for their contribution was found in late adolescence. Our results suggest that genetic factors play a major role in the variation of BMI in adolescence among populations of different ethnicities exposed to different environmental factors related to obesity. © 2016 American Society for Nutrition.

  20. Genetic liability to disability pension in women and men: a prospective population-based twin study.

    Directory of Open Access Journals (Sweden)

    Jurgita Narusyte

    Full Text Available BACKGROUND: Previous studies of risk factors for disability pension (DP have mainly focused on psychosocial, or environmental, factors, while the relative importance of genetic effects has been less studied. Sex differences in biological mechanisms have not been investigated at all. METHODS: The study sample included 46,454 Swedish twins, consisting of 23,227 complete twin pairs, born 1928-1958, who were followed during 1993-2008. Data on DP, including diagnoses, were obtained from the National Social Insurance Agency. Within-pair similarity in liability to DP was assessed by calculating intraclass correlations. Genetic and environmental influences on liability to DP were estimated by applying discrete-time frailty modeling. RESULTS: During follow-up, 7,669 individuals were granted DP (18.8% women and 14.1% men. Intraclass correlations were generally higher in MZ pairs than DZ pairs, while DZ same-sexed pairs were more similar than opposite-sexed pairs. The best-fitting model indicated that genetic factors contributed 49% (95% CI: 39-59 to the variance in DP due to mental diagnoses, 35% (95% CI: 29-41 due to musculoskeletal diagnoses, and 27% (95% CI: 20-33 due to all other diagnoses. In both sexes, genetic effects common to all ages explained one-third, whereas age-specific factors almost two-thirds, of the total variance in liability to DP irrespective of diagnosis. Sex differences in liability to DP were indicated, in that partly different sets of genes were found to operate in women and men, even though the magnitude of genetic variance explained was equal for both sexes. CONCLUSIONS: The findings of the study suggest that genetic effects are important for liability to DP due to different diagnoses. Moreover, genetic contributions to liability to DP tend to differ between women and men, even though the overall relative contribution of genetic influences does not differ by sex. Hence, the pathways leading to DP might differ between women and

  1. Do childhood and adult socioeconomic circumstances influence health and physical function in middle-age?

    DEFF Research Database (Denmark)

    Osler, Merete; Madsen, Mia; Nybo Andersen, Anne-Marie

    2009-01-01

    -twin, while there seemed to be no twin pair difference in dental status. This suggests that the associations of adult social class with functional l