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

    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...... given that the co-twin has the disease. Most diseases have a varying age-of-onset that will lead to age-specific prevalence. Typically, this aspect is not considered, and this may lead to severe bias as well as make it very unclear exactly what population quantities that we are estimating. In addition......, one will typically need to deal with censoring in the data, that is the fact that we for some subjects only know that they are alive at a specific age without having the disease. These subjects needs to be considered age specifically, and clearly if they are young there is still a risk...

  2. Paternal age and telomere length in twins

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Dalgård, Christine; Mangino, Massimo

    2015-01-01

    . Based on two independent (discovery and replication) twin studies, comprising 889 twin pairs, we show an increase in the resemblance of leukocyte telomere length between dizygotic twins of older fathers, which is not seen in monozygotic twins. This phenomenon might result from a paternal age...

  3. 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

    Twin pairs discordant for disease may help elucidate the epigenetic mechanisms and causal environmental factors in disease development and progression. To obtain the numbers of pairs, especially monozygotic (MZ) twin pairs, necessary for in-depth studies while also allowing for replication, twin...... 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......, 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...

  4. Intellectual similarity of virtual twin pairs: Developmental trends

    OpenAIRE

    2007-01-01

    Virtual twins (VTs) are same-age unrelated siblings reared together from infancy who replicate twinship, but without the genetic relatedness. A 2005 report from the ongoing Fullerton Virtual Twin Study found an IQ intraclass correlation of .26 (p < .01, n = 113 pairs) and a within-pair difference of 13.22 IQ points. The average age of VTs in that study was 8.10 years (SD = 8.56, range: 4.01–54.84 years). An opportunity to retest members of 43 VT pairs, 1.70–8.96 years after their time 1 asses...

  5. Intellectual similarity of virtual twin pairs: Developmental trends.

    Science.gov (United States)

    Segal, Nancy L; McGuire, Shirley A; Havlena, June; Gill, Patricia; Hershberger, Scott L

    2007-05-01

    Virtual twins (VTs) are same-age unrelated siblings reared together from infancy who replicate twinship, but without the genetic relatedness. A 2005 report from the ongoing Fullerton Virtual Twin Study found an IQ intraclass correlation of .26 (p < .01, n = 113 pairs) and a within-pair difference of 13.22 IQ points. The average age of VTs in that study was 8.10 years (SD = 8.56, range: 4.01-54.84 years). An opportunity to retest members of 43 VT pairs, 1.70-8.96 years after their time 1 assessment, allowed additional analyses of genetic and environmental influences underlying general intellectual development. A decrease in the VT IQ correlation and an increase in the within-pair difference were indicated, consistent with increasing genetic and/or non-shared environmental influences and decreasing shared environmental influence on general intellectual development throughout childhood.

  6. Paired twins and [112] morphology in GaP nanowires.

    Science.gov (United States)

    Algra, Rienk E; Verheijen, Marcel A; Feiner, Lou-Fé; Immink, George G W; Theissmann, Ralf; van Enckevort, Willem J P; Vlieg, Elias; Bakkers, Erik P A M

    2010-07-14

    Formation of random as well as periodic planar defects can occur during vapor-liquid-solid growth of nanowires with the zinc-blende crystal structure. Here we investigate the formation of pairs of twin planes in GaP nanowires. In such pairs, the first twin plane is formed at a random position, rapidly followed by the formation of a second twin plane of which the position is directly related to that of the first one. We show that the triangular [112] morphology of the nanowire is a key element in the formation of these twin pairs. We have extended our previous kinetic nucleation model and show that this describes the development of the nanowire morphology and its relation with the formation of single and paired twin planes.

  7. Birth size and age at menarche: a twin perspective.

    Science.gov (United States)

    Sørensen, Kaspar; Juul, Anders; Christensen, Kaare; Skytthe, Axel; Scheike, Thomas; Kold Jensen, Tina

    2013-10-01

    Do birthweight (BW) and co-twin sex influence the age at menarche in twins? BW, but not co-twin sex, was associated with age at menarche in twins. However, BW was not associated with age at menarche after controlling for genetics and shared rearing environment. Nutritional deprivation during critical developmental periods can trigger long-term effects on health. A small size at birth has been associated with early age at menarche in singletons. However, the relative influence of genetics and environmental factors on this association remains unresolved. In total, 2505 twin pairs were included in this cohort study. All participants were recruited from the Danish Twin Register. Data on the age at menarche were collected by questionnaire and combined with data on BW, birth length (BL) and gestational age (GA) from the Danish Medical Birth register. The BW for GA standard deviation score (BW-SDS) was calculated. BW-SDS [hazard ratio (HR) 0.96; 95% confidence interval (CI): 0.93-0.00], P = 0.04], but not BW, BL or GA (P ≥ 0.15), was positively associated with age at menarche in all twins after adjustment for zygosity and year of birth. However, BW-SDS was not associated with menarcheal age within twin pairs (HR 1.01; 95% CI: 0.91-1.12, P = 0.88). No differences were found in the age at menarche or birth size between twin girls from same sex and twin girls from opposite-sex pregnancies. Heritability of menarcheal age and BW were estimated to be 0.61 (95% CI: 0.38-0.84) and 0.27 (95% CI: 0.18-0.38), respectively. Both BW and menarcheal age were influenced by genetic and environmental factors. A limitation of this study is recall bias on the age at menarche. It is also not clear how these results should be extrapolated to the non-twin population. lower BW for GA is associated with earlier age at menarche in twin girls. However, the lack of within-pair differences in menarcheal age between even markedly BW-discordant twins indicates that this association is governed by

  8. Heredity of small hard drusen in twins aged 20-46 years

    DEFF Research Database (Denmark)

    Munch, Inger Christine; Sander, Birgit; Kessel, Line

    2007-01-01

    PURPOSE: To examine the prevalence and heredity of small hard drusen in 220 healthy twins aged 20-46 years. METHODS: Grayscale digital fundus photography, four-field 50 degrees nonstereoscopic, in red-free illumination was performed in 58 pairs of monozygotic (MZ) twins and 52 pairs of dizygotic...... (DZ) twins as part of a detailed biometric characterization. Small hard drusen (diameters,

  9. A registry of adult African American twins: the Carolina African American Twin Study of Aging.

    Science.gov (United States)

    Whitfield, Keith E

    2013-02-01

    Twin studies have seldom addressed ethnicity as one of the possible factors that create unique combinations of genetic and environmental influences. The major objective of the Carolina African American Twin Study of Aging is to identify the proportion of the genetic and environmental sources of individual variation in measures of health and behavioral factors in a sample of adult African Americans. Drawn from birth records from the State of North Carolina, this in-person study used public records to identify a cohort of twins between 22 and 92 years of age (X = 49.82 yrs, SD = 14.62), 39.7% of which were men. Members of non-intact twin pairs and siblings were also recruited to explore alternative models to the classic twin design. To date, the project has contributed to knowledge about blood pressure, forced expiratory volume, chronic illness, body mass index, and waist-hip ratio memory, personality, social, and demographic factors, mortality, and mental health.

  10. 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

    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......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....... 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...

  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. 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.

  13. A nongenetic basis of cycle frequency in bipolar disorder: study of a monozygotic twin pair.

    Science.gov (United States)

    Sharma, V; Ainsworth, P J; McCabe, S B; Persad, E; Kueneman, K M

    1997-01-01

    The authors describe a pair of monozygotic twins with bipolar disorder but with a different course of the illness including age of onset, sequence of episodes, and cycle length. Based on these findings, the clinical course of bipolar illness does not appear to be genetically determined. PMID:9074308

  14. [Refsum syndrome in a pair of monozygotic twins].

    Science.gov (United States)

    Kohnen, S; Hammerstein, W

    1993-10-01

    We report the case of a pair of twins with the ophthalmological and functional findings of Refsum syndrome. The twins were monozygotic twin brothers whose ophthalmological symptoms were noticed when they were in their forties. The diagnosis in the first brother led to a search for findings in the second. It was possible to attribute the non-specific subjective complaints to this as yet unknown syndrome. No causal therapy can be offered the patients. However, knowledge of the biochemical basis of the disease makes it possible to treat it by means of diet. In patients with retinopathia pigmentosa, an attempt should be made to identify Refsum syndrome if neurological symptoms are found in addition.

  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. 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…

  17. Inspection Time and Cognitive Abilities in Twins Aged 7 to 17 Years: Age-Related Changes, Heritability and Genetic Covariance

    Science.gov (United States)

    Edmonds, Caroline J.; Isaacs, Elizabeth B.; Visscher, Peter M.; Rogers, Mary; Lanigan, Julie; Singhal, Atul; Lucas, Alan; Gringras, Paul; Denton, Jane; Deary, Ian J.

    2008-01-01

    We studied the age-related differences in inspection time and multiple cognitive domains in a group of monozygotic (MZ) and dizygotic (DZ) twins aged 7 to 17 years. Data from 111 twin pairs and 19 singleton siblings were included. We found clear age-related trends towards more efficient visual information processing in older participants. There…

  18. Copy number variation distribution in six monozygotic twin pairs discordant for schizophrenia.

    Science.gov (United States)

    Castellani, Christina A; Awamleh, Zain; Melka, Melkaye G; O'Reilly, Richard L; Singh, Shiva M

    2014-04-01

    We have evaluated copy number variants (CNVs) in six monozygotic twin pairs discordant for schizophrenia. The data from Affymetrix® Human SNP 6.0 arrays™ were analyzed using Affymetrix® Genotyping Console™, Partek® Genomics Suite™, PennCNV, and Golden Helix SVS™. This yielded both program-specific and overlapping results. Only CNVs called by Affymetrix Genotyping Console, Partek Genomics Suite, and PennCNV were used in further analysis. This analysis included an assessment of calls in each of the six twin pairs towards identification of unique CNVs in affected and unaffected co-twins. Real time polymerase chain reaction (PCR) experiments confirmed one CNV loss at 7q11.21 that was found in the affected patient but not in the unaffected twin. The results identified CNVs and genes that were previously implicated in mental abnormalities in four of the six twin pairs. It included PYY (twin pairs 1 and 5), EPHA3 (twin pair 3), KIAA1211L (twin pair 4), and GPR139 (twin pair 5). They represent likely candidate genes and CNVs for the discordance of four of the six monozygotic twin pairs for this heterogeneous neurodevelopmental disorder. An explanation for these differences is ontogenetic de novo events that differentiate in the monozygotic twins during development.

  19. 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

    DEFF Research Database (Denmark)

    Dubois, Lise; Ohm Kyvik, Kirsten; Girard, Manon

    2012-01-01

    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.......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....

  20. Multiple Regression Analysis of Reading Performance Data from Twin Pairs with Reading Difficulties and Non-twin Siblings: The Augmented Model

    OpenAIRE

    Wadsworth, S J; Olson, R. K.; Willcutt, E.G.; DeFries, J. C.

    2012-01-01

    The augmented multiple regression model for the analysis of data from selected twin pairs was extended to facilitate analyses of data from twin pairs and non-twin siblings. Fitting this extended model to data from both selected twin pairs and siblings yields direct estimates of heritability (h2) and the difference between environmental influences shared by members of twin pairs and those of sib or twin/sib pairs [i.e., c2(t) − c2(s)]. When this model was fitted to reading performance data fro...

  1. Aging and communication in the twin paradox

    Science.gov (United States)

    de Wolf, David A.

    2016-11-01

    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.

  2. Aging and communication in the twin paradox

    CERN Document Server

    de Wolf, David A

    2016-01-01

    The twin paradox of the special theory of relativity has given rise 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.

  3. 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.

  4. Stressful life events and depression among adolescent twin pairs.

    Science.gov (United States)

    Boardman, Jason D; Alexander, Kari B; Stallings, Michael C

    2011-01-01

    Using the twin pairs sample from the National Longitudinal Study ofAdolescent Health, we estimate bivariate Cholesky models for the influence of stressful life events (SLEs) on depressive symptoms. We show that depressive symptoms (h2Depression = .28) and dependent SLEs (events influenced by an individual's behavior) are both moderately heritable (h2SLE Dependent = .43). We find no evidence for the heritability of independent SLEs. Results from the bivariate Cholesky model suggest that roughly one-half of the correlation between depression and dependent SLEs is due to common genetic factors. Our findings suggest that attempts to characterize the causal effect of SLEs on mental health should limit their list of SLEs to those that are outside of the control of the individual.

  5. Surprising dissimilarities in a newly formed pair of 'identical twin' stars.

    Science.gov (United States)

    Stassun, Keivan G; Mathieu, Robert D; Cargile, Phillip A; Aarnio, Alicia N; Stempels, Eric; Geller, Aaron

    2008-06-19

    The mass and chemical composition of a star are the primary determinants of its basic physical properties-radius, temperature and luminosity-and how those properties evolve with time. Accordingly, two stars born at the same time, from the same natal material and with the same mass, are 'identical twins,' and as such might be expected to possess identical physical attributes. We have discovered in the Orion nebula a pair of stellar twins in a newborn binary star system. Each star in the binary has a mass of 0.41 +/- 0.01 solar masses, identical to within 2 per cent. Here we report that these twin stars have surface temperatures differing by approximately 300 K ( approximately 10 per cent) and luminosities differing by approximately 50 per cent, both at high confidence level. Preliminary results indicate that the stars' radii also differ, by 5-10 per cent. These surprising dissimilarities suggest that one of the twins may have been delayed by several hundred thousand years in its formation relative to its sibling. Such a delay could only have been detected in a very young, definitively equal-mass binary system. Our findings reveal cosmic limits on the age synchronization of young binary stars, often used as tests for the age calibrations of star-formation models.

  6. Brain Activation during Memory Encoding in Type 2 Diabetes Mellitus: A Discordant Twin Pair Study

    Directory of Open Access Journals (Sweden)

    Amanda G. Wood

    2016-01-01

    Full Text Available Type 2 diabetes mellitus increases the risk of dementia and neuronal dysfunction may occur years before perceptible cognitive decline. We aimed to study the impact of type 2 diabetes on brain activation during memory encoding in middle-aged people, controlling for age, sex, genes, and early-shared environment. Twenty-two twin pairs discordant for type 2 diabetes mellitus (mean age 60.9 years without neurological disease were recruited from the Australian Twin Registry (ATR and underwent functional magnetic resonance imaging (fMRI during a memory encoding task, cognitive tests, and structural MRI. Type 2 diabetes was associated with significantly reduced activation in left hemisphere temporoparietal regions including angular gyrus, supramarginal gyrus, and middle temporal gyrus and significantly increased activation in bilateral posteriorly distributed regions. These findings were present in the absence of within-pair differences in standard cognitive test scores, brain volumes, or vascular lesion load. Differences in activation were more pronounced among monozygotic (MZ pairs, with MZ individuals with diabetes also displaying greater frontal activation. These results provide evidence for preclinical memory-related neuronal dysfunction in type 2 diabetes. They support the search for modifiable later-life environmental factors or epigenetic mechanisms linking type 2 diabetes and cognitive decline.

  7. Social activity and healthy aging: a study of aging Danish twins.

    Science.gov (United States)

    McGue, Matt; Christensen, Kaare

    2007-04-01

    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 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 level of physical functioning, cognitive functioning, and depression symptomatology. We also found that social activity was significantly and moderately heritable (estimate of .36), raising the possibility that its association with late-life functioning might reflect selection processes. Further, social 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. These results are interpreted in the context of the additional finding that nonshared environmental factors, although apparently not social activity, are the predominant determinant of changes in late-life functioning.

  8. Genetic and environmental effects on age at menarche, and its relationship with reproductive health in twins.

    Science.gov (United States)

    Jahanfar, Shayesteh; Lye, Munn-Sann; Krishnarajah, Isthrinayagy S

    2013-04-01

    Menarche or first menstrual period is a landmark in reproductive life span and it is the most prominent change of puberty. The timing of menarche can be under the influence of genes as well as individual environmental factors interacting with genetic factors. Our study objectives were (a) to investigate the heritability of age of menarche in twins, (b) to obtain the association between age of menarche and childhood factors, and reproductive events/behavior, (c) to examine whether or not having a male co-twin affects early/late menarche. A group of female-female identical (n = 108, 54 pairs), non-identical twins (n = 68, 34 pairs) and 17 females from opposite-sex twin sets were identified from twin registries of Malaysia and Iran. Genetic analysis was performed via two methods of Falconers' formula and maximum likelihood. Heritability was found to be 66% using Falconers' formula and 15% using univariate twin analysis. Model analysis revealed that shared environmental factors have a major contribution in determining the age of menarche (82%) followed by non-shared environment (18%). Result of this study is consistent with that of the literature. Timing of menarche could be under the influence of shared and non-shared environmental effects. Hirsutism was found to have a higher frequency among subjects with late menarche. There was no significant difference in age of menarche between females of opposite-sex twins and females of same-sex twins. It is concluded that twin models provide a powerful means of examining the total genetic contribution to age of menarche. Longitudinal studies of twins may clarify the type of environmental effects that determine the age of menarche.

  9. Movement Disorders in a Twins Pair: A Casual Expression or Genetic Determination?

    Science.gov (United States)

    Gennaro, Leonarda; Russo, Luigi; Losito, Luciana; Zaccaria, Alessia; De Rinaldis, Marta; Trabacca, Antonio

    2010-01-01

    A twin study is an excellent means of assessing the contribution of heritability to motor behaviour. We present a movement video-analysis of a monozygotic twins pair with a motor repertoire which is almost totally constituted by persistent and subcontinuous motor stereotypies. Purpose: The specific aim of this study is to verify the heritable…

  10. The contribution of twins to the study of cognitive ageing and dementia: the Older Australian Twins Study.

    Science.gov (United States)

    Sachdev, Perminder S; Lee, Teresa; Wen, Wei; Ames, David; Batouli, Amir H; Bowden, Jocelyn; Brodaty, Henry; Chong, Elizabeth; Crawford, John; Kang, Kristan; Mather, Karen; Lammel, Andrea; Slavin, Melissa J; Thalamuthu, Anbupalam; Trollor, Julian; Wright, Margie J

    2013-12-01

    The Older Australian Twins Study (OATS) is a major longitudinal study of twins, aged ≥ 65 years, to investigate genetic and environmental factors and their interactions in healthy brain ageing and neurocognitive disorders. The study collects psychiatric, neuropsychological, cardiovascular, metabolic, biochemical, neuroimaging, genomic and proteomic data, with two-yearly assessments, and is currently in its third wave. The initial cohort comprises 623 individuals (161 monozygotic and 124 dizygotic twin pairs; 1 MZ triplets; 27 single twins and 23 non-twin siblings), of whom 426 have had wave 2 assessment. A number of salient findings have emerged thus far which assist in the understanding of genetic contributions to cognitive functions such as processing speed, executive ability and episodic memory, and which support the brain reserve hypothesis. The heritability of brain structures, both cortical and subcortical, brain spectroscopic metabolites and markers of small vessel disease, such as lacunar infarction and white matter hyperintensities, have been examined and can inform future genetic investigations. Work on amyloid imaging and functional magnetic resonance imaging is proceeding and epigenetic studies are progressing. This internationally important study has the potential to inform research into cognitive ageing in the future, and offers an excellent resource for collaborative work.

  11. 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.

  12. Metabolism of sex steroids is influenced by acquired adiposity-A study of young adult male monozygotic twin pairs.

    Science.gov (United States)

    Vihma, Veera; Naukkarinen, Jussi; Turpeinen, Ursula; Hämäläinen, Esa; Kaprio, Jaakko; Rissanen, Aila; Heinonen, Sini; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Mikkola, Tomi S; Tikkanen, Matti J; Pietiläinen, Kirsi H

    2017-09-01

    Obesity and ageing are associated with lower serum testosterone levels in men. How fat distribution or adipose tissue metabolism, independent of genetic factors and age, are related to sex steroid metabolism is less clear. We studied the associations between adiposity and serum sex hormone concentrations, and mRNA expression of genes regulating sex hormone metabolism in adipose tissue in young adult male monozygotic (MZ) twin pairs. The subjects [n=18 pairs; mean age, 32 years; individual body mass indexes (BMIs) 22-36kg/m(2)] included 9 male MZ twin pairs discordant for BMI [intra-pair difference (Δ) in BMI ≥3kg/m(2)]. Sex steroid concentrations were determined by liquid chromatography-tandem mass spectrometry, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and mRNA expressions from subcutaneous adipose tissue by Affymetrix. In BMI-discordant pairs (mean ΔBMI=5.9kg/m(2)), serum dihydrotestosterone (DHT) was lower [mean 1.9 (SD 0.7) vs. 2.4 (1.0) nmol/l, P=0.040] and mRNA expressions of DHT-inactivating AKR1C2 (P=0.021) and cortisol-producing HSD11B1 (P=0.008) higher in the heavier compared to the leaner co-twins. Serum free 17β-estradiol (E2) was higher [2.3 (0.5) vs. 1.9 (0.5) pmol/l, P=0.028], and in all twin pairs, serum E2 and estrone concentrations were higher in the heavier than in the leaner co-twins [107 (28) vs. 90 (22) pmol/l, P=0.006; and 123 (43) vs. 105 (27) pmol/l, P=0.025]. Within all twin pairs, i.e. independent of genetic effects and age, 1) the amount of subcutaneous fat inversely correlated with serum total and free testosterone, DHT, and sex hormone-binding globulin (SHBG) concentrations (Padiposity correlated positively with mRNA expressions of AKR1C2, HSD11B1, and aromatase in adipose tissue (Padiposity was associated with decreased serum DHT and increased estrogen concentrations, independent of genetic factors and age. The reduction of DHT could be linked to its increased degradation (by AKR1C2 and

  13. A Twin-Study of Sleep Difficulties in School-Aged Children

    Science.gov (United States)

    Gregory, Alice M.; Rijsdijk, Fruhling V.; Eley, Thalia C.

    2006-01-01

    This study examines frequency, overlap, and genetic and environmental influences on sleep difficulties, which are understudied in school-aged children. The Sleep Self Report and the Children's Sleep Habits Questionnaire were completed by 300 twin pairs (aged 8 years) and their parents. Child report suggested more frequent sleep problems than…

  14. 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....

  15. Filaggrin gene loss-of-function mutations explain discordance of atopic dermatitis within dizygotic twin pairs

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; Elmose, Camilla; Szecsi, Pal Bela

    2016-01-01

    OBJECTIVES: This study was designed to examine the association between loss-of-function mutations in the filaggrin gene (FLG) and atopic dermatitis (AD) and asthma in adult twins. METHODS: A previously well-characterized cohort of 575 adult twins were genotyped for the loss-of-function mutations...... in FLG (R501X, 2282del4 and R2447X) most common among northern Europeans. Subjects were examined for symptoms of atopic diseases as well as for lung function, airway responsiveness, and atopy. RESULTS: In the whole population of twins, the risk for AD was significantly increased in individuals with FLG...... no significant differences in risk for asthma by FLG mutation status in individuals with and without AD, respectively (P-value for interaction, 0.595). In 11 dizygotic twin pairs discordant for FLG mutation status, risk for AD was higher in the twin carrying the FLG mutation (five of 11 [45.5%] twins had...

  16. Genetic and environmental influences on sleep quality in middle-aged men: a twin study.

    Science.gov (United States)

    Genderson, Margo R; Rana, Brinda K; Panizzon, Matthew S; Grant, Michael D; Toomey, Rosemary; Jacobson, Kristen C; Xian, Hong; Cronin-Golomb, Alice; Franz, Carol E; Kremen, William S; Lyons, Michael J

    2013-10-01

    Poor sleep quality is a risk factor for a number of cognitive and physiological age-related disorders. Identifying factors underlying sleep quality are important in understanding the etiology of these age-related health disorders. We investigated the extent to which genes and the environment contribute to subjective sleep quality in middle-aged male twins using the classical twin design. We used the Pittsburgh Sleep Quality Index to measure sleep quality in 1218 middle-aged twin men from the Vietnam Era Twin Study of Aging (mean age = 55.4 years; range 51-60; 339 monozygotic twin pairs, 257 dizygotic twin pairs, 26 unpaired twins). The mean PSQI global score was 5.6 [SD = 3.6; range 0-20]. Based on univariate twin models, 34% of variability in the global PSQI score was due to additive genetic effects (heritability) and 66% was attributed to individual-specific environmental factors. Common environment did not contribute to the variability. Similarly, the heritability of poor sleep-a dichotomous measure based on the cut-off of global PSQI>5-was 31%, with no contribution of the common environment. Heritability of six of the seven PSQI component scores (subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, and daytime dysfunction) ranged from 0.15 to 0.31, whereas no genetic influences contributed to the use of sleeping medication. Additive genetic influences contribute to approximately one-third of the variability of global subjective sleep quality. Our results in middle-aged men constitute a first step towards examination of the genetic relationship between sleep and other facets of aging. © 2013 European Sleep Research Society.

  17. 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.

  18. Paternal age and twinning in the Jerusalem Perinatal Study

    Science.gov (United States)

    Kleinhaus, Karine; Perrin, Mary C.; Manor, O; Friedlander, Yehiel; Calderon-Margalit, Ronit; Harlap, Susan; Malaspina, Dolores

    2008-01-01

    Objective To investigate whether incidence of twin deliveries is related to father's age, independently of mother's age, and whether it differs for same-sex or opposite-sex twin sets. Study Design In a program of research on effects of paternal age, this study used data from a prospective cohort of 92,408 offspring born in Jerusalem from 1964-1976. Of the 91,253 deliveries in the Jerusalem Perinatal Study, 1,115 were twin deliveries. The data were analyzed with General Estimate Equations to inform unconditional logistic regression. Results After controlling for maternal age, Odds Ratios (OR) and 95% Confidence Intervals (95% CI) associated with father's ages 25-34 and 35+ were 1.3 (1.1, 1.7) and 1.5 (1.2, 2.1) respectively, compared with fathers <25 years old. The effect of maternal age was partly explained by paternal age. The ORs for opposite-sex twin sets and male-male twin sets increased slightly with paternal age, while the OR for same-sex and female-female twin decreased. Conclusion Studies of twins are used to estimate effects of genes and environment in a variety of diseases. Our findings highlight the need to consider paternal as well as maternal age when analyzing data on twins to explore etiology of diseases. PMID:18771839

  19. 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.

  20. Paternal age and telomere length in twins: the germ stem cell selection paradigm.

    Science.gov (United States)

    Hjelmborg, Jacob B; Dalgård, Christine; Mangino, Massimo; Spector, Tim D; Halekoh, Ulrich; Möller, Sören; Kimura, Masayuki; Horvath, Kent; Kark, Jeremy D; Christensen, Kaare; Kyvik, Kirsten O; Aviv, Abraham

    2015-08-01

    Telomere length, a highly heritable trait, is longer in offspring of older fathers. This perplexing feature has been attributed to the longer telomeres in sperm of older men and it might be an 'epigenetic' mechanism through which paternal age plays a role in telomere length regulation in humans. Based on two independent (discovery and replication) twin studies, comprising 889 twin pairs, we show an increase in the resemblance of leukocyte telomere length between dizygotic twins of older fathers, which is not seen in monozygotic twins. This phenomenon might result from a paternal age-dependent germ stem cell selection process, whereby the selected stem cells have longer telomeres, are more homogenous with respect to telomere length, and share resistance to aging.

  1. A twin study of the genetics of high cognitive ability selected from 11,000 twin pairs in six studies from four countries.

    Science.gov (United States)

    Haworth, Claire M A; Wright, Margaret J; Martin, Nicolas W; Martin, Nicholas G; Boomsma, Dorret I; Bartels, Meike; Posthuma, Danielle; Davis, Oliver S P; Brant, Angela M; Corley, Robin P; Hewitt, John K; Iacono, William G; McGue, Matthew; Thompson, Lee A; Hart, Sara A; Petrill, Stephen A; Lubinski, David; Plomin, Robert

    2009-07-01

    Although much genetic research has addressed normal variation in intelligence, little is known about the etiology of high cognitive abilities. Using data from 11,000 twin pairs (age range = 6-71 years) from the genetics of high cognitive abilities consortium, we investigated the genetic and environmental etiologies of high general cognitive ability (g). Age-appropriate psychometric cognitive tests were administered to the twins and used to create g scores standardized within each study. Liability-threshold model fitting was used to estimate genetic and environmental parameters for the top 15% of the distribution of g. Genetic influence for high g was substantial (0.50, with a 95% confidence interval of 0.41-0.60). Shared environmental influences were moderate (0.28, 0.19-0.37). We conclude that genetic variation contributes substantially to high g in Australia, the Netherlands, the United Kingdom and the United States.

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

    Science.gov (United States)

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

    2012-06-01

    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 siblings (Astrom et al., 2011). Results suggest that proband reading deficits are due substantially to genetic factors (.67 ± .07, p < .001), and that shared environmental influences are significantly higher for members of twin pairs than for those of twins and their nontwin siblings (viz., .25 versus .17, p = .02).

  3. 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.

  4. Genetic Factors Explain Variation in the Age at Onset of Psoriasis: A Population-based Twin Study.

    Science.gov (United States)

    Lønnberg, Ann Sophie; Skov, Lone; Duffy, David Lorenzo; Skytthe, Axel; Kyvik, Kirsten Ohm; Pedersen, Ole Birger; Thomsen, Simon Francis

    2016-01-01

    The aim of this study was to determine the age at onset of psoriasis in a population-based twin sample. Questionnaire-data in 10,725 twin pairs, 20-71 years of age, from the Danish Twin Registry, was collected, and analysed using survival regression analysis. Median age at onset was 25 and 28 years among women and men, respectively. The correlation between the ages was 0.84 (bootstrap standard error?=?0.044) in monozygotic twin pairs and 0.60 (0.051) in dizygotic twin pairs, permutation p?=?0.001. Age at onset of psoriasis in the index twin did not predict risk of psoriasis in the co-twin, hazard ratio (per year of later onset =?1.01 (0.99-1.03), p?=?0.434. In conclusion, these data support that the age at onset of psoriasis is, in part, an inherited property. Our results do not support that early-onset psoriasis is more genetically determined.

  5. Differentially Methylated Genomic Regions in Birth-Weight Discordant Twin Pairs

    DEFF Research Database (Denmark)

    Chen, Mubo; Baumbach, Jan; Vandin, Fabio

    2016-01-01

    twin pairs to find evidence for such “programming” effects, but no significant results emerged. We further investigated this issue using a new computational approach: Instead of probing single genomic sites for significant alterations in epigenetic marks, we scan for differentially methylated genomic...... regions. Whole genome DNA methylation levels were measured in whole blood from 150 pairs of adult identical twins discordant for birth-weight. Intrapair differential DNA methylation was associated with qualitative (large or small) and quantitative (percentage) birth-weight discordance at each genomic site...

  6. Twins for epigenetic studies of human aging and development

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; Thomassen, Mads

    2013-01-01

    , our understanding of genetic and environmental influences on the epigenetic processes remains limited. Twins are of special interest for genetic studies due to their genetic similarity and rearing-environment sharing. The classical twin design has made a great contribution in dissecting the genetic...... 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...

  7. 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 metabolic disorders and health behaviors during puberty and young adulthood. Adult twins have been sampled for studying heritability of multiple phenotypes associated with metabolic disorders. In addition, an elderly twin cohort has been recruited with a focus on genetic studies of aging-related phenotypes...

  8. 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…

  9. 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...... whether unaffected cotwins have an increased frequency of orbicularis oris muscle defects, a subclinical form of orofacial cleft. The presence of such defects may reduce the overall rate of discordance. METHOD: A total of 63 discordant monozygotic and dizygotic twin pairs, 262 unaffected nontwin siblings......, and 543 controls with no history of orofacial clefts were assessed for orbicularis oris defects by high-resolution ultrasound. Frequencies were compared by the Fisher exact test. RESULTS: Unaffected cotwins from discordant monozygotic pairs had a higher frequency of defects (12.5%) than the other test...

  10. Individual Differences in Dynamic Measures of Verbal Learning Abilities in Young Twin Pairs and Their Older Siblings

    Science.gov (United States)

    van Soelen, Inge L. C.; van den Berg, Stephanie M.; Dekker, Peter H.; van Leeuwen, Marieke; Peper, Jiska S.; Hulshoff Pol, Hilleke E.; Boomsma, Dorret I.

    2009-01-01

    We explored the genetic background of individual differences in dynamic measures of verbal learning ability in children, using a Dutch version of the Auditory Verbal Learning Test (AVLT). Nine-year-old twin pairs (N = 112 pairs) were recruited from the Netherlands Twin Register. When possible, an older sibling between 10 and 14 years old…

  11. Individual Differences in Dynamic Measures of Verbal Learning Abilities in Young Twin Pairs and Their Older Siblings

    Science.gov (United States)

    van Soelen, Inge L. C.; van den Berg, Stephanie M.; Dekker, Peter H.; van Leeuwen, Marieke; Peper, Jiska S.; Hulshoff Pol, Hilleke E.; Boomsma, Dorret I.

    2009-01-01

    We explored the genetic background of individual differences in dynamic measures of verbal learning ability in children, using a Dutch version of the Auditory Verbal Learning Test (AVLT). Nine-year-old twin pairs (N = 112 pairs) were recruited from the Netherlands Twin Register. When possible, an older sibling between 10 and 14 years old…

  12. 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

    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....... 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...... scores, and were also less often moderate drinkers and nonsmokers compared with married men. Divorced/widowed women had higher depression scores and those divorced/widowed or never married were more often smokers than married women. Within twin pairs discordant on marital status, the divorced...

  13. Health-Related Findings Among Twin Pairs Discordant for Leisure-Time Physical Activity for 32 Years: The TWINACTIVE Study Synopsis.

    Science.gov (United States)

    Leskinen, Tuija; Kujala, Urho M

    2015-06-01

    We are lacking very long-term and controlled intervention studies investigating the effects of habitual physical activity on health-related factors. To address this gap, we performed a natural experiment by identifying same-sex twin pairs in which the co-twins of each pair differed with respect to leisure-time physical-activity habits throughout their adult life. Our criterion for the discordance was that the same co-twin had a higher leisure time-activity volume than that of the other member of the pair at the majority -- if not all -- of the follow-up time points according to reported/interviewed physical-activity data. Overall, we identified and conducted multidimensional health-related measurements (including fitness, body composition, cardiometabolic risk factor levels, bone and arterial status, and exercise motivation) of 16 twin pairs (seven monozygotic (MZ) and nine dizygotic (DZ) pairs, mean age 60 years) who had persistent discordance in leisure-time physical-activity habits over three decades (TWINACTIVE study). In our discordant-pair study design, after adjusting for sequence-level genes, both systemic-level metabolic, and site-specific structural findings differed significantly in the pairwise analysis in MZ pairs only. These findings included intrapair differences in accumulated fat depots and structure of heart, arteries, and bones. In addition, our study revealed intrapair differences in metabolic and regulatory pathways, which may partly explain the mechanistic links between long-term physical activity, phenotypic changes, and decreased risk of cardiometabolic diseases.

  14. 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...... modeling on FEV1, FVC, handgrip, and FTSST in 379 twin pairs (240 MZ and 139 DZ) with median age of 50 years (40-80 years). Data were analyzed by fitting univariate and bivariate twin models to estimate the genetic and environmental influences on these measures of physical function. Heritability...... environment (40-50%). Bivariate analysis showed highly positive genetic correlations between FEV1 and FVC (r G = 1.00), and moderately negative genetic correlations between FTSST and FEV1 (r G = -0.33) and FVC (r G = -0.42). FEV1 and FVC, as well as FEV1 and handgrip, displayed high common environmental...

  15. Estimating Modifying Effect of Age on Genetic and Environmental Variance Components in Twin Models.

    Science.gov (United States)

    He, Liang; Sillanpää, Mikko J; Silventoinen, Karri; Kaprio, Jaakko; Pitkäniemi, Janne

    2016-04-01

    Twin studies have been adopted for decades to disentangle the relative genetic and environmental contributions for a wide range of traits. However, heritability estimation based on the classical twin models does not take into account dynamic behavior of the variance components over age. Varying variance of the genetic component over age can imply the existence of gene-environment (G×E) interactions that general genome-wide association studies (GWAS) fail to capture, which may lead to the inconsistency of heritability estimates between twin design and GWAS. Existing parametricG×Einteraction models for twin studies are limited by assuming a linear or quadratic form of the variance curves with respect to a moderator that can, however, be overly restricted in reality. Here we propose spline-based approaches to explore the variance curves of the genetic and environmental components. We choose the additive genetic, common, and unique environmental variance components (ACE) model as the starting point. We treat the component variances as variance functions with respect to age modeled by B-splines or P-splines. We develop an empirical Bayes method to estimate the variance curves together with their confidence bands and provide an R package for public use. Our simulations demonstrate that the proposed methods accurately capture dynamic behavior of the component variances in terms of mean square errors with a data set of >10,000 twin pairs. Using the proposed methods as an alternative and major extension to the classical twin models, our analyses with a large-scale Finnish twin data set (19,510 MZ twins and 27,312 DZ same-sex twins) discover that the variances of the A, C, and E components for body mass index (BMI) change substantially across life span in different patterns and the heritability of BMI drops to ∼50% after middle age. The results further indicate that the decline of heritability is due to increasing unique environmental variance, which provides more

  16. 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......, our understanding of genetic and environmental influences on the epigenetic processes remains limited. Twins are of special interest for genetic studies due to their genetic similarity and rearing-environment sharing. The classical twin design has made a great contribution in dissecting the genetic...... 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...

  17. 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, Pfasting 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.

  18. DeFries-Fulker analysis of longitudinal reading performance data from twin pairs ascertained for reading difficulties and from their nontwin siblings.

    Science.gov (United States)

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

    2011-09-01

    Reading difficulties are both heritable and stable; however, little is known about the etiology of this stability. Results from a preliminary analysis of data from 56 twin pairs who participated in the Colorado Longitudinal Twin Study of Reading Disability (Astrom et al., Twin Res Hum Genet 10:434-439, 2007) suggested that about two-thirds of the proband deficit at follow-up was due to genetic factors that also influenced deficits at their initial assessment. Although our proband sample is now nearly twice as large, it is still relatively small; thus, to increase power, we subjected data from probands, co-twins and their nontwin siblings to a novel extension of DeFries-Fulker analysis (DeFries and Fulker, Behav Genet 15:467-473, 1985; DeFries and Fulker, Acta Genet Med Gemellol, 37, 205-216, 1988). In addition to providing estimates of univariate and bivariate heritability, this analysis facilitates a test of the difference between shared environmental influences for twins versus siblings. Longitudinal composite reading performance scores at 10.6 and 15.5 years of age, on average, were analyzed from 33 MZ and 64 DZ twin pairs in which at least one member of each pair had reading difficulties, and from 44 siblings of the probands. Scores were highly stable (.86 ± .03, across probands, co-twins and siblings) and heritability of the group deficit at initial assessment was .67 ± .22. Longitudinal bivariate heritability was .59 ± .21, suggesting that nearly 60% of the proband reading deficit at follow-up is due to genetic factors that influenced reading difficulties at the initial assessment. However, tests for special twin environmental influences were nonsignificant.

  19. Path analytic, sib-pair linkage and co-twin control studies of asthma and atopy

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, D.L.; Healey, S.C.; Martin, N.G. [Queensland Institute of Medical Research, Brisband (Austria)

    1994-09-01

    Asthma and atopy are complex traits with multifactorial determinants, and require appropriate choice of phenotypes and analyses, including a linkage analysis of the putative 11q atopy locus. Participants in a large registry-based twin study of asthma were invited to take part in clinical testing. A total of 863 individuals including 419 complete twin pairs (where one or both members reported a history of wheeze) underwent histamine inhalation challenge, allergen skin prick testing, and venesection. Total serum immunoglobulin E (IgE) and bronchial responsiveness (BR) to histamine were highest in those who had wheezed most recently, and whose skin tests demonstrated allergy to house dust mite, cockroach, and rye grass. In ascertainment-corrected path analyses (FISHER), the heritability of IgE and BR were both 60%. Monozygotic (MZ) co-twin control analyses suggested house dust mite sensitization was the single strongest environmentally controlled risk factor for wheeze, while path analyses suggested genetic determination. In dizygotic (DZ) co-twin control analyses, sensitization to grasses was also an important predictor, suggesting pollinosis to be genetically correlated with wheezing, rather than causative. Multivariate path analyses suggested separate (correlated) genetic factors for BR, IgE, and allergy to house dust mite. A sib-pair (Haseman-Elston) linkage analysis of 220 DZ twin pairs did not support linkage to the high-affinity IgE receptor beta-subunit gene on 11q13 of atopy or BR. More recent linkage analyses that include parental genotyping will also be discussed. We conclude that the atopic phenotype consists of a number of traits with specific genetic allergens. Exposure to particular allergens can then cause specific outcomes, such as asthma.

  20. Ectopic neuroblastoma in monozygotic twins with different ages of onset: possible twin-to-twin metastasis in utero with distinct genetic alterations after birth.

    Science.gov (United States)

    Taketani, Takeshi; Takita, Junko; Ueyama, Junichi; Kanai, Rie; Kumori, Koji; Maruyama, Riruke; Hayashi, Kazuhiko; Ogawa, Seishi; Fukuda, Seiji; Yamaguchi, Seiji

    2014-03-01

    We describe neuroblastoma (NB) in monozygotic twins whose ages at the onset of the disease had a 3-year interval. The primary tumor site of twin 1 was the adrenal gland, whereas that of twin 2 was the jejunum/mesentery. MYCN amplification, DNA index, ALK mutation, and copy number alterations of DNA were different between each primary tumor. NB in ectopic sites may have resulted from twin-to-twin metastasis through vascular anastamoses in the placenta. The pathogenesis of this NB involved a premalignant stage of NB during the fetal development and subsequent molecular alterations after birth, resulting in NBs that were phenotypically similar but genetically different.

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

    OpenAIRE

    Lívia Azeredo Alves Antunes; Erika Calvano Küchler; Marcelo de Castro Costa; Leonardo Santos Antunes; José Mauro Granjeiro

    2013-01-01

    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 employ...

  2. 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

    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....

  3. The Danish Twin Register

    DEFF Research Database (Denmark)

    Kyvik, K O; Christensen, Kaare; Skytthe, A;

    1996-01-01

    BACKGROUND: Population based twin registers represent a valuable tool for genetic epidemiological research, since twin studies aim at separating the effect of genes and environment for complex traits. The Danish Twin Register's history, size, ascertainment and completeness of data, as well as data...... accessibility and availability are described. RESULTS: The Danish Twin Register comprises 14,051 twin pairs born 1870-1930, representing all twins surviving to age six years, and 20,888 twin pairs born 1953-1982, representing 75% of those born 1953-1967 and 95% of those born 1968-1982. The birth cohorts 1931......-1952 og 1983-1993 are being ascertained at the moment. The register is available for research given certain conditions are fulfilled. CONCLUSION: This register will in a few years be the most comprehensive twin register in the world. It is a very valuable Danish research resource....

  4. The Danish Twin Register

    DEFF Research Database (Denmark)

    Kyvik, K O; Christensen, Kaare; Skytthe, A

    1996-01-01

    BACKGROUND: Population based twin registers represent a valuable tool for genetic epidemiological research, since twin studies aim at separating the effect of genes and environment for complex traits. The Danish Twin Register's history, size, ascertainment and completeness of data, as well as data...... accessibility and availability are described. RESULTS: The Danish Twin Register comprises 14,051 twin pairs born 1870-1930, representing all twins surviving to age six years, and 20,888 twin pairs born 1953-1982, representing 75% of those born 1953-1967 and 95% of those born 1968-1982. The birth cohorts 1931......-1952 og 1983-1993 are being ascertained at the moment. The register is available for research given certain conditions are fulfilled. CONCLUSION: This register will in a few years be the most comprehensive twin register in the world. It is a very valuable Danish research resource....

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

    Science.gov (United States)

    Antunes, Lívia Azeredo Alves; Küchler, Erika Calvano; Costa, Marcelo de Castro; Antunes, Leonardo Santos; Granjeiro, José Mauro

    2013-11-01

    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.

  6. [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.

  7. 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

    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......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...... is unknown. METHODS: Data on the 1-month prevalence of neck pain from twin pairs participating in the population based Longitudinal Study of Aging Danish Twins formed the basis of this analysis. To assess twin similarity, probandwise concordance rates, odds ratios, and tetrachoric correlations were...

  8. Genetic influence on age at first birth of female twins born in the UK, 1919–68

    NARCIS (Netherlands)

    Tropf, F.C.; Barban, N.; Mills, M.C.; Snieder, H.; Mandemakers, J.J.

    2015-01-01

    Using a sample of monozygotic (945, 42 per cent) and dizygotic (1,329, 58 per cent) twin pairs born 1919–68 in the UK, we applied innovative tobit models to investigate genetic and environmental influences on age at first birth (AFB). We found that a substantial part (40 per cent) of the variation

  9. Genetic influence on age at first birth of female twins born in the UK, 1919–68

    NARCIS (Netherlands)

    Tropf, F.C.; Barban, N.; Mills, M.C.; Snieder, H.; Mandemakers, J.J.

    2015-01-01

    Using a sample of monozygotic (945, 42 per cent) and dizygotic (1,329, 58 per cent) twin pairs born 1919–68 in the UK, we applied innovative tobit models to investigate genetic and environmental influences on age at first birth (AFB). We found that a substantial part (40 per cent) of the variation i

  10. Genetic influence on age at first birth of female twins born in the UK, 1919-68

    NARCIS (Netherlands)

    Tropf, Felix C.; Barban, Nicola; Mills, Melinda C.; Snieder, Harold; Mandemakers, Jornt J.

    2015-01-01

    Using a sample of monozygotic (945, 42 per cent) and dizygotic (1,329, 58 per cent) twin pairs born 1919-68 in the UK, we applied innovative tobit models to investigate genetic and environmental influences on age at first birth (AFB). We found that a substantial part (40 per cent) of the variation i

  11. Influence of genetic and environmental factors on oral diseases and function in aged twins.

    Science.gov (United States)

    Kurushima, Y; Ikebe, K; Matsuda, K; Enoki, K; Ogata, S; Yamashita, M; Murakami, S; Hayakawa, K; Maeda, Y

    2015-01-01

    This study was conducted to quantify the genetic and environmental contributions to oral disease and function in twins. Participants were middle-aged and old twins, 116 monozygotic and 16 dizygotic pairs whose mean age was 66·1 ± 10·3 (SD) years. Number of teeth, percentage of decayed, filled and missing teeth and periodontal status were recorded as indicators of oral disease. The widths of upper and lower dental arch served as indicators of morphological figures. Furthermore, stimulated salivary flow rate, occlusal force and masticatory performance were measured as indicators of oral function. Univariate genetic analysis with monozygotic and dizygotic twin pairs was conducted to detect the fittest structural equation model of each outcome. Both number of teeth and periodontal status fitted the model composed of common environmental factor and unique environmental factor. Decayed, filled and missing teeth, morphological figures and measurements of oral function fitted the model composed of additive genetic factor and unique environmental factor. The model fitting of each measurement suggested that periodontal disease was mainly affected by environmental factors, while morphological figures and oral functions were influenced by both genetic and environmental factors.

  12. Correlation between lithium abundances and ages of solar twin stars

    CERN Document Server

    Carlos, Marilia; Melendez, Jorge

    2016-01-01

    We want to determine the lithium abundances of solar twin stars as a function of stellar age to provide constraints for stellar evolutions models and to investigate whether there is a connection between low Li abundance and the occurrence of planets. For a sample of 21 solar twins observed with the HARPS spectrograph at high spectral resolution (R~115.000) and very high signal-to-noise ratio (600 < S/N < 2400), precise lithium abundances were obtained by spectral synthesis of the LiI 6707.8 A line and compared to stellar ages, masses, and metallicities determined from a spectroscopic analysis of the same set of HARPS spectra. We show that for the large majority of the solar twins there is a strong correlation between lithium abundance and stellar age. As the age increases from 1 to 9 Gyr, the Li abundance decreases by a factor of ~ 50. The relation agrees fairly well with predictions from non-standard stellar evolution models of Li destruction at the bottom of the upper convection zone. Two stars deviat...

  13. Divergent frequencies of IGF-I receptor-expressing blood lymphocytes in monozygotic twin pairs discordant for Graves' disease: evidence for a phenotypic signature ascribable to nongenetic factors

    DEFF Research Database (Denmark)

    Douglas, Raymond S; Brix, Thomas H; Hwang, Catherine J

    2009-01-01

    Twin Registry, including seven discordant pairs, four pairs concordant for GD, and seven healthy pairs. MAIN OUTCOME MEASURES: Subjects underwent physical examination and laboratory analysis. Surface display of IGF-IR on T and B cells was analyzed by flow cytometry. RESULTS: Twins with GD display...

  14. Evolutionary developmental transition from median to paired morphology of vertebrate fins: Perspectives from twin-tail goldfish.

    Science.gov (United States)

    Abe, Gembu; Ota, Kinya G

    2016-12-07

    Vertebrate morphology has been evolutionarily modified by natural and/or artificial selection. The morphological variation of goldfish is a representative example. In particular, the twin-tail strain of ornamental goldfish shows highly diverged anal and caudal fin morphology: bifurcated anal and caudal fins. Recent molecular developmental genetics research revealed that a stop codon mutation in one of the two recently duplicated chordin genes is important for the highly diverged fin morphology of twin-tail goldfish. However, some issues still need to be discussed in the context of evolutionary developmental biology (evo-devo). For example, the bifurcated anal and caudal fins of twin-tail goldfish provided early researchers with insights into the origin of paired fins (pectoral and pelvic fins), but no subsequent researchers have discussed this topic. In addition, although the fossil jawless vertebrate species Euphanerops is also known to have had a bifurcated anal fin, how the bifurcated anal fin of twin-tail goldfish is related to that of fossil jawless vertebrate species has never been investigated. In this review, we present an overview of the early anatomical and embryological studies of twin-tail goldfish. Moreover, based on the similarity of embryonic features between the secondarily bifurcated competent stripe in twin-tail goldfish and the trunk bilateral competent stripes in conventional gnathostomes, we hypothesized that they share the same molecular developmental mechanisms. We also postulate that the bifurcated anal fin of Euphanerops might be caused by the same type of modification of dorsal-ventral patterning that occurs in the twin-tail goldfish, unlike the previously suggested evolutionary process that required the co-option of paired fin developmental mechanisms. Understanding the molecular developmental genetics of twin-tail goldfish allows us to further investigate the evolutionary developmental mechanisms of the origin of paired fins.

  15. Paired Border Towns or TwinCities from Finland and China

    Institute of Scientific and Technical Information of China (English)

    Riitta Kosonen; Xu Feng; Erja Kettunen

    2008-01-01

    This paper discusses cross-border cooperation at the level of urban socio-economic systems.Worldwide,cross-border urban cooperation has in several cases produced socio-economic and political coherence supported by various joint programs and efforts.However,the degree of coherence varies and seldom creates socio-economically and politically tightly integrated "TwinCities" where the state border becomes highly transparent or obscure.Focusing on Finland and China,our aim is to identify whether the selected border towns represent coherent TwinCities or a more loose type of "paired border towns".The study uses an empirical examination of three Finnish towns (Helsinki,Tomio,Imatra) and their neighboring towns in Estonia,Sweden,and Russia as a benchmark.Then,a comparative study is made regarding three Chinese eross-border cities facing Russia,Vietnam and Kazakhstan.We highlight the differences in cross-border integration from the viewpoint of shared public sector programs,cross-border enterprise relocation and networking,and integrated social sector in terms of labor market,education and shopping area.

  16. A study of the birth weight-obesity relation using a longitudinal cohort and sibling and twin pairs.

    Science.gov (United States)

    The, Natalie S; Adair, Linda S; Gordon-Larsen, Penny

    2010-09-01

    Sibling and twin study designs provide control for confounding factors that are typically unmeasured in traditional cohort studies. Using nationally representative data from the National Longitudinal Study of Adolescent Health collected at 3 visits during 1994-2002, the authors evaluated the longitudinal association between birth weight and later obesity in a traditional cohort study (n = 13,763; ages 11-21 years at baseline), controlling for sex, age, race/ethnicity, and parental education. Among persons with a nonobese mother, high birth weight (>4 kg) participants were more likely than normal birth weight (>/=2.5-the authors examined longitudinal within-pair differences. Birth weight difference was positively associated with body mass index difference later in life for female monozygotic pairs only (beta = 2.67, 95% confidence interval: 0.99, 4.35). Given the null associations observed in the sibling sample, the commonly observed positive association between birth weight and later obesity from cohort analyses may be attributed to confounding by maternal characteristics. Further research is needed to identify specific factors that contribute to the birth weight-obesity relation.

  17. 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.

  18. Small for gestational age and exposure to particulate air pollution in the early-life environment of twins.

    Science.gov (United States)

    Bijnens, Esmée M; Derom, Catherine; Gielen, Marij; Winckelmans, Ellen; Fierens, Frans; Vlietinck, Robert; Zeegers, Maurice P; Nawrot, Tim S

    2016-07-01

    Several studies in singletons have shown that maternal exposure to ambient air pollutants is associated with restricted fetal growth. About half of twins have low birth weight compared with six percent in singletons. So far, no studies have investigated maternal air pollution exposure in association with birth weight and small for gestational age in twins. We examined 4760 twins of the East Flanders Prospective Twins Survey (2002-2013), to study the association between in utero exposure to air pollution with birth weight and small for gestational age. Maternal particulate air pollution (PM10) and nitric dioxide (NO2) exposure was estimated using a spatial temporal interpolation method over various time windows during pregnancy. In the total group of twins, we observed that higher PM10 and NO2 exposure during the third trimester was significantly associated with a lower birth weight and higher risk of small for gestational age. However, the association was driven by moderate to late preterm twins (32-36 weeks of gestation). In these twins born between 32 and 36 weeks of gestation, birth weight decreased by 40.2g (95% CI: -69.0 to -11.3; p=0.006) and by 27.3g (95% CI: -52.9 to -1.7; p=0.04) in association for each 10µg/m³ increment in PM10 and NO2 concentration during the third trimester. The corresponding odds ratio for small for gestational age were 1.68 (95% CI: 1.27-2.33; p=0.0003) and 1.51 (95% CI: 1.18-1.95; p=0.001) for PM10 or NO2, respectively. No associations between air pollution and birth weight or small for gestational age were observed among term born twins. Finally, in all twins, we found that for each 10µg/m³ increase in PM10 during the last month of pregnancy the within-pair birth weight difference increased by 19.6g (95% CI: 3.7-35.4; p=0.02). Assuming causality, an achievement of a 10µg/m³ decrease of particulate air pollution may account for a reduction by 40% in small for gestational age, in twins born moderate to late preterm.

  19. A genome-wide association study of monozygotic twin-pairs suggests a locus related to variability of serum high-density lipoprotein cholesterol

    DEFF Research Database (Denmark)

    Surakka, Ida; Whitfield, John B; Perola, Markus

    2012-01-01

    in serum lipid and apolipoprotein levels. We report data for 1,720 monozygotic female twin-pairs from GenomEUtwin project with 2.5 million SNPs, imputed or genotyped, and measured serum lipid fractions for both twins. We found one locus associated with intra-pair differences in high-density lipoprotein...

  20. Genetic and Environmental Contributions to Stability and Change of ADHD Symptoms between 8 and 13 Years of Age: A Longitudinal Twin Study

    Science.gov (United States)

    Larsson, Jan-Olov; Larsson, Henrik; Lichtenstein, Paul

    2004-01-01

    Objective: To study the genetic and environmental contributions to stability and change of attention-deficit/hyperactivity disorder (ADHD) symptoms between 8 and 9 and 13 and 14 years of age. Method: The sample included 1,480 twin pairs born in Sweden between May 1985 and December 1986. At wave 1 in 1994, when twins were 8-9 years old, 1,106 (75%)…

  1. Pair production of neutral Higgs bosons from the left-right twin Higgs model via γγ collisions

    Institute of Scientific and Technical Information of China (English)

    马威; 岳崇兴; 张婷婷

    2011-01-01

    The left-right twin Higgs (LRTH) model predicts the existence of the neutral Higgs bosons (h, φ0), which can be produced in pairs (φ0φ0, hh, φ0h) via γγ collisions at the next generation e+eInternational Linear Collider (ILC). Our numerical results show t

  2. Leukocyte telomere length and physical ability among Danish twins age 70+

    DEFF Research Database (Denmark)

    Bendix, Laila; Gade, Maria Monrad; Staun, Pia Wirenfeldt;

    2011-01-01

    Leukocyte telomere length (LTL) shortens with age and is potentially a biomarker of human aging. We examined the relation of LTL with physical ability and cognitive function in 548 same-sex twins from the Longitudinal Study of Aging Danish Twins. LTL was measured by Southern blots of the terminal...

  3. Growth references for height, weight and body mass index of twins aged 0-2.5 years

    NARCIS (Netherlands)

    Dommelen, P. van; Gunst, M. de; Vaart, A.D. van; Buuren, S. van; Boomsma, D.

    2008-01-01

    Aim: To determine the size of the growth deficit in Dutch monozygotic and dizygotic twins aged 0-2.5 years as compared to singletons and to construct reference growth charts for twins. Methods: Growth of twins was studied using longitudinal data on over 4000 twins aged 0-2.5 years of the Netherlands

  4. 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...... of 1137 same-sex twin pairs (356 MZ and 781 DZ pairs) in which one or both members were diagnosed with AF were identified in The Danish Twin Registry. Concordance rates were twice as high for MZ pairs than for DZ pairs regardless of sex (22.0% versus 11.6%, P...-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...

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

    Directory of Open Access Journals (Sweden)

    Janine H Stubbe

    Full Text Available 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 GenomEUtwin project were used. METHODOLOGY: 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. PRINCIPAL FINDINGS: 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. CONCLUSIONS: 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. 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

  7. The morphology of the sella turcica in monozygotic twins.

    Science.gov (United States)

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

    2009-12-01

    The purpose was to compare the sella turcica morphology of individuals within pairs of monozygotic twins with normal karyotype and to analyze the similarity between the observed morphology and the morphology of non-twins at the same age with normal karyotype. Profile radiographs from 84 individuals 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 coefficient was used for comparison of individuals within twin pairs. For comparison of twins and non-twins, normal standard values for length, depth and diameter were subtracted from the twin values. For the mean values of these differences, confidence limits p values and t values were calculated. The study 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 in sizes are observed between individuals in the twin material and individuals in the non-twin material. As a conclusion, the twin males were more similar within the twin pair, but deviated more from the non-twin material than the females. Female twins had more discrepancy within the twin pair, but deviated less from the non-twin material than the males.

  8. 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

    CONTEXT: Microchimerism is the presence of small populations of cells from one individual in another genetically distinct individual. This phenomenon can arise from pregnancy, blood transfusion, or bidirectional cell trafficking between twins in utero. Microchimerism has recently been proposed...... 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...

  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. 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.

  11. 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....

  12. 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....

  13. A Multivariate Twin Study of Early Literacy in Japanese "Kana"

    Science.gov (United States)

    Fujisawa, Keiko K.; Wadsworth, Sally J.; Kakihana, Shinichiro; Olson, Richard K.; DeFries, John C.; Byrne, Brian; Ando, Juko

    2013-01-01

    This first Japanese twin study of early literacy development investigated the extent to which genetic and environmental factors influence individual differences in prereading skills in 238 pairs of twins at 42 months of age. Twin pairs were individually tested on measures of phonological awareness, "kana" letter name/sound knowledge,…

  14. 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.

  15. 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

    of controlling for both unmeasured common childhood-environmental factors as well as genetic factors shared by the co-twins. Two twin studies suggest the existence of genetic mediation between birthweight and IQ, that is, common genetic factors influence both fetal growth and IQ in childhood, while two other......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...... 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...

  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. Age-dependent trajectories differ between within-pair and extra-pair paternity success.

    Science.gov (United States)

    Hsu, Y-H; Simons, M J P; Schroeder, J; Girndt, A; Winney, I S; Burke, T; Nakagawa, S

    2017-02-24

    Reproductive success is associated with age in many taxa, increasing in early life followed by reproductive senescence. In socially monogamous but genetically polygamous species, this generates the interesting possibility of differential trajectories of within-pair and extra-pair siring success with age in males. We investigate these relationships simultaneously using within-individual analyses with 13 years of data from an insular house sparrow (Passer domesticus) population. As expected, we found that both within- and extra-pair paternity success increased with age, followed by a senescence-like decline. However, the age trajectories of within- and extra-pair paternity successes differed significantly, with the extra-pair paternity success increasing faster, although not significantly, in early life, and showing a delayed decline by 1.5 years on average later in life compared to within-pair paternity success. These different trajectories indicate that the two alternative mating tactics should have age-dependent pay-offs. Males may partition their reproductive effort between within- and extra-pair matings depending on their current age to reap the maximal combined benefit from both strategies. The interplay between these mating strategies and age-specific mortality may explain the variation in rates of extra-pair paternity observed within and between species.

  18. 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

    expiratory volume in one second (FEV1), forced vital capacity (FVC), handgrip strength, five-times-sit-to-stand test (FTSST), near visual acuity, and number of teeth lost in 379 complete twin pairs. Bivariate twin models were fitted to estimate the genetic and environmental correlation between physical......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...

  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. Pair production of neutral Higgs bosons from the left-right twin Higgs model via γγ collisions

    Institute of Scientific and Technical Information of China (English)

    MA Wei; YUE Chong-Xing; ZHANG Ting-Ting

    2011-01-01

    The left-right twin Higgs (LRTH) model predicts the existence of the neutral Higgs bosons (h, φ), which can be produced in pairs (φφ, hh, φh) via γγ collisions at the next generation ee International Linear Collider (ILC). Our numerical results show that the production cross section of the neutral Higgs boson pair φφ can reach 8.8 fb. The subprocess γγ→φφ might be used to test the LRTH model in future ILC experiments.

  1. X-chromosome inactivation patterns in monozygotic twins and sib pairs discordant for nonsyndromic cleft lip and/or palate

    DEFF Research Database (Denmark)

    Kimani, Jane W; Shi, Min; Daack-Hirsch, Sandra

    2007-01-01

    Nonsyndromic clefts of the lip and/or palate are common birth defects with a strong genetic component. Based on unequal gender ratios for clefting phenotypes, evidence for linkage to the X chromosome and the occurrence of several X-linked clefting syndromes, we investigated the role of skewed X...... of XCI was defined as the deviation in inactivation pattern from a 50:50 ratio. Our analysis revealed no significant difference in the degree of skewing between twin pairs (P = 0.3). However, borderline significant differences were observed in the sister pairs (P = 0.02), with the cleft lip with cleft......, particularly cleft lip and palate....

  2. Profile of asymmetrical retinopathy of prematurity in twins

    Directory of Open Access Journals (Sweden)

    Azad Rajvardhan

    2010-01-01

    Full Text Available Background: In twin births, both babies have the same gestational age and pre-natal conditions. However, twins may develop a varied retinopathy of prematurity (ROP course depending on birth weight and other systemic factors. Objective: To study the profile of asymmetric ROP in twins Design: Retrospective study Setting: Tertiary ROP referral eye hospital. Materials and Methods: The profile of 56 pairs of twins with ROP were studied and analyzed for differences in zone or need for treatment, while studying possible causes for the varied outcome. Results: In 45 pairs of twins (80% the disease progressed identically in both eyes, while in 11 pairs (20% the ROP showed differences in zone or need for treatment. Four of these pairs were discordant. In 3 of these 4 pairs, the heavier birth weight twin had a more severe ROP course. Conclusions: Twins can present with asymmetric ROP course, and it is therefore essential to examine both twins as per screening protocols.

  3. Heritability of eleven metabolic phenotypes in Danish and Chinese twins

    DEFF Research Database (Denmark)

    Li, Shuxia; Duan, Hongmei; Pang, Zengchang

    2013-01-01

    A twin-based comparative study on the genetic influences in metabolic endophenotypes in two populations of substantial ethnic, environmental, and cultural differences was performed. Design and Methods: Data on 11 metabolic phenotypes including anthropometric measures, blood glucose, and lipids...... levels as well as blood pressure were available from 756 pairs of Danish twins (309 monozygotic and 447 dizygotic twin pairs) with a mean age of 38 years (range: 18-67) and from 325 pairs of Chinese twins (183 monozygotic and 142 dizygotic twin pairs) with a mean age of 40.5 years (range: 18-69). Twin...... similar heritability patterns in the two samples with body weight showing only a slight difference. Higher genetic influences were estimated for fasting blood glucose level in Chinese twins, whereas the Danish twins showed more genetic regulation over most lipids phenotypes. Systolic blood pressure...

  4. Spina bifida occulta and monozygotic twins.

    Science.gov (United States)

    Spacca, Barbara; Buxton, Neil

    2008-10-01

    Central nervous system maldevelopment can have different presentations in twins. We report on a case of different presentations of spina bifida occulta in monozygotic twins. The first twin presented at birth with a lipomyelomeningocele; a tethered cord was diagnosed in the second twin at 2 years of age. Neural tube defects (NTDs) are a group of common congenital malformations of the brain and spine generated during neurulation. The genetic basis of this process is still not well known. Whenever an NTD is diagnosed in one of a pair of twins, the other twin should also be evaluated for NTDs.

  5. Birthweight percentiles for twin birth neonates by gestational age in China

    Science.gov (United States)

    Zhang, Bin; Cao, Zhongqiang; Zhang, Yiming; Yao, Cong; Xiong, Chao; Zhang, Yaqi; Wang, Youjie; Zhou, Aifen

    2016-01-01

    Localized birthweight references for gestational ages serve as an essential tool in accurate evaluation of atypical birth outcomes. Such references for twin births are currently not available in China. The aim of this study was to construct up-to-data sex specific birth weight references by gestational ages for twin births in China. We conducted a population-based analysis on the data of 22,507 eligible living twin infants with births dated between 8/01/2006 and 8/31/2015 from all 95 hospitals within the Wuhan area. Gestational ages in complete weeks were determined using a combination of last-menstrual-period based (LMP) estimation and ultrasound examination. Smoothed percentile curves were created by the Lambda Mu Sigma (LMS) method. Reference of the 3rd, 10th, 25th, 50th, 75th, 90th, 97th percentiles birth weight by sex and gestational age were made using 11,861 male and 10,646 female twin newborns with gestational age 26–42 weeks. Separate birthweight percentiles curves for male and female twins were constructed. In summary, our study firstly presents percentile curves of birthweight by gestational age for Chinese twin neonates. Further research is required for the validation and implementation of twin birthweight curves into clinical practice. PMID:27506479

  6. 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

    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...... = 14) non-diabetic co-twins, respectively (MZ: mean +/- SEM 2634 +/- 135 vs 2829 +/- 131 g, p

  7. Timing of Colonization of Caries-Producing Bacteria: An Approach Based on Studying Monozygotic Twin Pairs

    OpenAIRE

    Bockmann, Michelle R.; Harris, Abbe V.; Bennett, Corinna N.; Ruba Odeh; Hughes, Toby E.; Townsend, Grant C

    2011-01-01

    Findings are presented from a prospective cohort study of timing of primary tooth emergence and timing of oral colonization of Streptococcus mutans (S. mutans) in Australian twins. The paper focuses on differences in colonization timing in genetically identical monozygotic (MZ) twins. Timing of tooth emergence was based on parental report. Colonization timing of S. mutans were established by plating samples of plaque and saliva on selective media at 3 monthly intervals and assessing colony mo...

  8. Socioeconomic position and twins' health

    DEFF Research Database (Denmark)

    Osler, Merete; McGue, Matt; Christensen, Kaare

    2007-01-01

    of middle-aged Danish twins was conducted in 1998-99. The study population included 1266 like-sex twin pairs [52.5% monozygotic (MZ) and 47.6% dizygotic (DZ)]. Data were obtained on childhood and adult social class and on height, BMI, grip strength, depression symptoms, self-rated health, cognitive function......, prenatal and rearing environmental factors from environmental factor later in life, we compared the health status among male and female twin pairs who lived together during childhood and were discordant or concordant on adult socioeconomic position. METHODS: A cross-sectional survey among a random sample......, physical activity, smoking, alcohol and food intake. RESULTS: The expected associations between the individual twins' adult social class and health measures were observed. Among DZ male twins discordant on adult social class, the higher social class twin was on average significantly taller and had higher...

  9. 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.

  10. The Qingdao Twin Registry: a status update.

    Science.gov (United States)

    Duan, Haiping; Ning, Feng; Zhang, Dongfeng; Wang, Shaojie; Zhang, Dong; Tan, Qihua; Tian, Xiaocao; Pang, Zengchang

    2013-02-01

    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 metabolic disorders and health behaviors during puberty and young adulthood. Adult twins have been sampled for studying heritability of multiple phenotypes associated with metabolic disorders. In addition, an elderly twin cohort has been recruited with a focus on genetic studies of aging-related phenotypes using twin modeling and genome-wide association analysis. Cross-cultural collaborative studies have been carried out between China, Denmark, Finland, and US cohorts. Ongoing data collection and analysis for the Qingdao Twin Registry will be discussed in this article.

  11. Comparison of Naturally Conceived and IVF-DZ Twins in the Netherlands Twin Registry: A Developmental Study

    Directory of Open Access Journals (Sweden)

    Catharina E. M. van Beijsterveldt

    2011-01-01

    Full Text Available In a large set of twin pairs, we compared twins born after IVF to naturally conceived twins with respect to birth characteristics, growth, attainment of motor milestones, and emotional and behavioral problems. Twin families were registered with the Netherlands Twin Register. We included 1534 dizygotic (DZ twins born after IVF, 5315 naturally conceived (NC DZ twins, and 1504 control NC DZ twins who were matched to the IVF twins based on maternal age, maternal educational level, smoking during pregnancy, gestational age, and offspring sex. Data were obtained by longitudinal surveys sent to fathers, mothers, and teachers at ages 1, 2, 3, 7, 10, and 12 years. Results showed no differences in growth, in attainment of motor milestones, and in behavioral development between IVF and matched NC twins. It can be concluded that for nearly all aspects, development in IVF and NC children is similar.

  12. Fullerton Virtual Twin Study: an update.

    Science.gov (United States)

    Segal, Nancy L; McGuire, Shirley A; Graham, Jamie L; Stohs, Joanne Hoven

    2013-02-01

    Virtual twins (VTs) are same-age unrelated siblings reared together from early infancy. These unique sibling sets replicate twinship, but without the genetic link. The first VT pair was identified and studied at the University of Minnesota in 1990, launching the development of the Fullerton Virtual Twin Study at California State University, Fullerton (CSUF) in 1991. The registry currently includes 151 pairs, mostly children, with new pairs identified on a continuous basis. Research with VTs includes studies of general intelligence, body size, interpersonal trust, social coordination, social networks, and parenting. In some cases, VTs have been studied in conjunction with pairs of monozygotic twins, dizygotic twins, full siblings, and friends as part of TAPS (Twins, Adoptees, Peers and Siblings), a collaborative project conducted between CSUF and the University of San Francisco, 2002-2006. VTs will also serve as a comparison group for epigenetic analyses of young Chinese twins reared apart and together.

  13. Epigenetic differences in cortical neurons from a pair of monozygotic twins discordant for Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Diego Mastroeni

    Full Text Available DNA methylation is capable of modulating coordinate expression of large numbers of genes across many different pathways, and may therefore warrant investigation for their potential role between genes and disease phenotype. In a rare set of monozygotic twins discordant for Alzheimer's disease (AD, significantly reduced levels of DNA methylation were observed in temporal neocortex neuronal nuclei of the AD twin. These findings are consistent with the hypothesis that epigenetic mechanisms may mediate at the molecular level the effects of life events on AD risk, and provide, for the first time, a potential explanation for AD discordance despite genetic similarities.

  14. Fullerton Virtual Twin Study.

    Science.gov (United States)

    Segal, Nancy L

    2006-12-01

    Virtual twins (VTs; same-age unrelated siblings reared together from early infancy) have been studied at California State University (CSU), Fullerton since 1991. The current sample includes over 130 pairs. Past and current research have research have focused on siblings' similarities and differences in general intelligence and body size. Future research in these areas will continue as new pairs continue to be identified. These studies will be supplemented by analyses of personality, social relations and adjustment using monozygotic (MZ) twins, dizygotic (DZ) twins, full siblings and friends, as well as new VTs, who have participated in Twins, Adoptees, Peers and Siblings (TAPS), a collaborative project conducted between CSU Fullerton and the University of San Francisco, from 2002 to 2006.

  15. Heritability of head size in dutch and Australian twin families at ages 0-50 years.

    NARCIS (Netherlands)

    Smit, D.J.; Luciano, M.; Bartels, M.; Beijsterveldt, C.E. van; Wright, M.J.; Hansell, N.K.; Brunner, H.G.; Estourgie-van Burk, G.F.; Geus, E.J. de; Martin, N.G.; Boomsma, D.I.

    2010-01-01

    We assessed the heritability of head circumference, an approximation of brain size, in twin-sib families of different ages. Data from the youngest participants were collected a few weeks after birth and from the oldest participants around age 50 years. In nearly all age groups the largest part of th

  16. 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.

  17. A monozygotic twin pair with β-thalassemia carrier status in a Dudh Kharia tribal family of Orissa

    Directory of Open Access Journals (Sweden)

    Balgir R

    2007-01-01

    Full Text Available Background: The β -thalassemia syndrome is a genetically inherited commonly encountered hematological disorder in the state of Orissa. It causes high degree of morbidity, mortality and fetal wastage in the poor vulnerable people. Aims and Objectives: There is an equal probability (50% chance in every singleton pregnancy that a carrier parent of β -thalassemia major would either bear normal or carrier offspring, but not two offspring with carrier of β -thalassemia major genotype together. For the first time, a carrier parent of β -thalassemia major gene has born progeny (three daughters and a twin male offspring with a carrier status of β -thalassemia major in Dudh Kharia tribal family studied from Sundargarh district of Orissa. Materials and Methods: We screened randomly selected population of Dudh Kharia tribe from Sundargarh district of Orissa for hemoglobinopathies to assess the extent of the problem, design possible interventions and provide genetic counseling to them. A family with twin children was identified during screening in Lata Gaon in Bargaon block of Sundargarh district of Orissa for the above-mentioned study. Background information for this family such as name, age, sex, tribe, native place, reproductive history, family pedigree and clinical signs and symptoms were also recorded. Standardized genetic and hematological procedures and techniques were followed for analysis. Results: Laboratory investigations for alkaline electrophoresis of blood lysate on cellulose acetate membrane showed raised hemoglobin A 2 level in mother (Hb A 2 = 5.3%, in three daughters (Hb A 2 =6.5, 5.9, 5.5% in chronological and birth order, in two twin sons (Hb A 2 =5.9% and 6.0% and normal (Hb A 2 = 3.3% for father. Hence, all the children i.e., three daughters and two twin sons, including the mother were β -thalassemia carriers. Since all the hematological parameters i.e., red cell indices, G-6-PD enzyme activity, ABO and Rhesus blood groups and

  18. Differentially methylated DNA regions in monozygotic twin pairs discordant for rheumatoid arthritis.An epigenome - wide study.

    Directory of Open Access Journals (Sweden)

    Anders Jørgen Svendsen

    2016-11-01

    Full Text Available Objectives: In an explorative epigenome-wide association study (EWAS to search for gene independent, differentially methylated DNA positions (DMPs and regions (DMRs associated with rheumatoid arthritis (RA by studying monozygotic (MZ twin pairs discordant for rheumatoid arthritis.Methods: Genomic DNA was isolated from whole blood samples from 28 monozygotic (MZ twin pairs discordant for RA. DNA methylation was measured using the HumanMethylation450 BeadChips. Smoking, anti-cyclic citrullinated peptide antibodies and immunosuppressive treatment were included as covariates. Pathway analysis was performed using GREAT.Results: 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 and EFCAB4B were hypomethylated and both genes have previously been associated with RA. We replicated several candidate genes identified in a previous EWAS in treatment naïve RA singletons. Gene set analysis indicated the involvement of immunologic signatures and cancer-related pathways in RA.Conclusion: 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 rheumatoid arthritis

  19. 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…

  20. 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…

  1. Assessment of heritability for personality, based on a short-form of the Eysenck Personality Inventory: a study of 12,898 twin pairs.

    Science.gov (United States)

    Floderus-Myrhed, B; Pedersen, N; Rasmuson, I

    1980-03-01

    The influence of genetic factors for two personality dimensions was analyzed using data from 12,898 unselected twin pairs of the Swedish Twin Registry. The heritability index was 0.50 (men) and 0.58 (women) for psychosocial instability. Corresponding figures for psychosocial extraversion were 0.54 and 0.66. Thus, about half the phenotypic variation may be attributed to genetic factors.

  2. 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

    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...... expiratory volume in one second (FEV1), forced vital capacity (FVC), handgrip strength, five-times-sit-to-stand test (FTSST), near visual acuity, and number of teeth lost in 379 complete twin pairs. Bivariate twin models were fitted to estimate the genetic and environmental correlation between physical...... 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...

  3. Persistence of placenta previa in twin gestations based on gestational age at sonographic detection.

    Science.gov (United States)

    Kohari, Katherine S; Roman, Ashley S; Fox, Nathan S; Feinberg, Jessica; Saltzman, Daniel H; Klauser, Chad K; Rebarber, Andrei

    2012-07-01

    The purpose of this study was to evaluate the gestational age at sonographic detection of placenta previa as a predictor of previa persistence until delivery in twin gestations. A retrospective cohort of twin pregnancies with placenta previa in a single ultrasound unit was analyzed from 2005 to 2010. Pregnancies were ascertained from a database. Diagnoses were confirmed by transvaginal imaging. Previa was categorized as complete if the placenta completely covered the internal os or marginal if the inferior placental edge reached within 2 cm. Gestational ages were grouped into intervals from 15 to 35 weeks. The study outcome was placenta previa at delivery. Only twin pregnancies at 25 weeks' gestation and later were analyzed using nonparametric statistics as appropriate, with P Placenta previa was detected in 120 twin pregnancies in the second trimester: 32 complete and 88 marginal. Of those with placenta previa at 15 to 19, 20 to 23, 24 to 27, 28 to 31, and 32 to 35 weeks, previa persisted until delivery in 8.3%, 19.2%, 50%, 75%, and 92.5%, respectively. Only at 15- to 19- and 20- to 23-week intervals was complete previa more likely to persist than marginal previa (P placenta previa persistence in twins is dependent on the gestational age at sonographic detection. Only at earlier gestations does the type of previa affect its persistence. As gestational age advances, the likelihood of resolution of placenta previa diminishes regardless of the type noted.

  4. Surprising Lack of Sex Differences in Normal Cognitive Aging in Twins

    Science.gov (United States)

    Finkel, Deborah; Reynolds, Chandra A.; Berg, Stig; Pedersen, Nancy L.

    2006-01-01

    Sex differences in the etiology of normal cognitive functioning in aging remain largely unexplored. We conducted an investigation of genetic and environmental contributions to sex differences in level of cognitive performance and rate of decline in the Swedish Adoption/Twin Study of Aging (SATSA) (Finkel & Pedersen, 2004) data set. Behavioral…

  5. 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.

  6. A twin study of computer anxiety in Turkish adolescents.

    Science.gov (United States)

    Deryakulu, Deniz; Calışkan, Erkan

    2012-04-01

    The present study investigated computer anxiety within a sample of Turkish twins aged 10-18. A total of 185 twin-pairs participated in the study. Of the twins, 64 pairs (34.6 percent) were monozygotic (MZ) and 121 pairs (65.4 percent) were dizygotic (DZ). Of the 121 DZ twins, 54 pairs (44.63 percent) were same-sex twins and 67 pairs (55.37 percent) were opposite-sex twins. Computer anxiety was assessed using Computer Anxiety Rating Scale-Turkish Version (CARS-TV), one of the three main scales of "Measuring Technophobia Instruments" developed by Rosen and Weil. The results of paired t test comparisons showed no significant differences in MZ and same-sex DZ twin-pairs' levels of computer anxiety. On the other hand, a significant difference was found in opposite-sex DZ twin-pairs' level of computer anxiety. Interesting enough, males appeared to be more computer anxious than their female co-twins. In the present study, using Falconer's formula, heritability estimate for computer anxiety was derived from correlations based on MZ and DZ twins' mean scores on CARS-TV. The results showed that 57 percent of the variance in computer anxiety was from genetics and 41.5 percent was from nonshared environmental factors. Shared environmental influence, on the other hand, was very small and negligible. Interpretations of results and potential directions for future research are presented.

  7. DeFries-Fulker and Pearson-Aitken model-fitting analyses of reading performance data from selected and unselected twin pairs.

    Science.gov (United States)

    Hawke, Jesse L; Stallings, Michael C; Wadsworth, Sally J; DeFries, John C

    2008-03-01

    Although a comparison of concordance rates for deviant scores in identical and fraternal twin pairs can provide prima facie evidence for a genetic etiology, information is not fully utilized when continuous measures are analyzed in a dichotomous manner. Thus, DeFries and Fulker (Behav Genet 15:467-473, 1985; Acta Genet Med Gemellol, 37:205-216, 1988) developed a regression-based methodology (DF analysis) to assess genetic etiology in both selected and unselected twin samples. While the DF analysis is a very versatile and relatively powerful statistical approach, it is not easily extended to the multivariate case. In contrast, structural equation models may be readily extended to analyze multivariate data sets (Neale and Cardon, Methodology for genetic studies of twins and families, 1992). However, such methodologies may yield biased estimates of additive genetic, shared environmental, and non-shared environmental influences when multivariate models are fitted to selected twin data. Therefore, the Pearson-Aitken (PA) selection formula (Aitken, Proc Edinburgh Math Soc B, 4:106-110, 1934) was used to analyze reading performance data from twins with reading difficulties (selected sample) and a population of normally-achieving twin pairs (control sample). As a comparison, DF models were also fitted to these same data sets. In general, resulting estimates of additive genetic, shared environmental, and non-shared environmental influences were similar when the DF and PA models were fitted to the data. However, the PA selection formula may be more readily generalized to the multivariate case.

  8. 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.

  9. 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.

  10. Common immune-related exposures/conditions and risk of non-Hodgkin lymphoma: a case-control study of disease-discordant twin pairs.

    Science.gov (United States)

    Wang, Jun; Mack, Thomas M; Hamilton, Ann S; Hwang, Amie E; Nathwani, Bharat N; Masood, Kamil; Buchanan, Laura H; Bernstein, Leslie; Deapen, Dennis M; Martínez-Maza, Otoniel; Cozen, Wendy

    2015-09-01

    We evaluated the association between common immune system-altering experiences and non-Hodgkin lymphoma (NHL) risk using a case-control study of 162 like-sex twin pairs discordant for NHL, identified from the International Twin Study. Information on medical history and evidence of childhood exposure to microbes was obtained by questionnaire from 1998 to 2002. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Intra-twin-pair agreement between twins on individual exposures was high (76%-97%). A negative association between NHL and seasonal hay fever (odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.10, 0.75) and certain allergies (OR = 0.29, 95% CI: 0.13, 0.68) was observed. The number of atopic diseases was negatively associated with NHL (P for trend = 0.0003). A history of infectious mononucleosis was negatively associated with NHL risk (OR = 0.35, 95% CI: 0.14, 0.90). NHL risk was associated with more frequent childhood exposure to microbes during early life (P for trend = 0.04). No differences in association by NHL subtype were observed, although statistical power for these comparisons was low. These observations support the hypothesis that immune-related exposures, especially atopy, are associated with decreased NHL risk. Use of the within-twin-pair study design mitigates confounding by genome, family structure, and unmeasured characteristics of early childhood factors.

  11. 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...

  12. Head Circumferences in Twins with and without Autism Spectrum Disorders

    Science.gov (United States)

    Froehlich, Wendy; Cleveland, Sue; Torres, Andrea; Phillips, Jennifer; Cohen, Brianne; Torigoe, Tiffany; Miller, Janet; Fedele, Angie; Collins, Jack; Smith, Karen; Lotspeich, Linda; Croen, Lisa A.; Ozonoff, Sally; Lajonchere, Clara; Grether, Judith K.; Hallmayer, Joachim

    2013-01-01

    To determine the genetic relationship between head circumference (HC) and Autism Spectrum Disorders (ASDs). Twin pairs with at least one twin with an ASD were assessed. HCs in affected and unaffected individuals were compared, as were HC correlations in monozygotic and dizygotic pairs. 404 subjects, ages 4-18, were included. 20% of males and 27%…

  13. 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.

  14. 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

    -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......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...

  15. The relationship between twin language, twins' close ties, and social competence.

    Science.gov (United States)

    Hayashi, Chisato; Mikami, Hiroshi; Nishihara, Reiko; Maeda, Chiho; Hayakawa, Kazuo

    2014-02-01

    This study investigated the relationship between twin language, twins' close ties, and social competence in a prospective longitudinal study. We hypothesized that twins whose tie is close would be more likely to develop a twin language, and these twins would be less likely to develop social competence. In addition, we hypothesize that some environmental factors, such as having an older sibling, preschool attendance, zygosity, and sex are also related to twin language, twins' close ties, and social competence. At baseline in 1999 a mailed questionnaire survey was conducted, and a follow-up questionnaire was distributed in 2004 among 958 mothers. As a result, 516 respondents returned the questionnaire (53.9%). In this study, we used 261 twin pairs aged from 6 to 12 years (school-age children) for analysis, excluding those with missing values. In the present study, we found that zygosity and sex were associated with twins' close ties. Having an older sibling and preschool attendance did not affect the twins' close tie, twin language, or social competence. One of the most important findings was that social competence was not affected directly by twins' close tie, but was affected when a twin language was found.

  16. 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

    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 ...

  17. Investigation of age and gender effects on positive orientation in Italian twins.

    Science.gov (United States)

    Fagnani, Corrado; Medda, Emanuela; Stazi, Maria A; Caprara, Gian V; Alessandri, Guido

    2014-12-01

    We investigated age and gender effects on "Positive Orientation" (POS)-an individual's tendency to view life with a positive outlook-using a genetically informed design. Study subjects were 1016 twins aged 22-75 from the Italian twin registry. We assessed POS by the recently developed P-scale. First, we used confirmatory factor analysis to investigate scale's measurement invariance by age and gender. Then, we applied biometric modelling to estimate genetic and environmental components of POS score. Overall, we found a satisfactory degree of measurement invariance by both age and gender. Results from these analyses further indicated an increasing mean level of POS across the lifespan. Additive genetic and unshared environmental factors explained respectively 58% and 42% of variance in POS score, with no significant gender differences; furthermore, the pattern of change of gene-environment architecture of POS over time was consistent with a greater plasticity of personality at older ages.

  18. 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...

  19. Effects of age on genetic influence on bone loss over 17 years in women: the Healthy Ageing Twin Study (HATS).

    Science.gov (United States)

    Moayyeri, Alireza; Hammond, Christopher J; Hart, Deborah J; Spector, Timothy D

    2012-10-01

    The rate of bone loss varies across the aging period via multiple complex mechanisms. Therefore, the role of genetic factors on bone loss may also change similarly. In this study, we investigated the effect of age on the genetic component of bone loss in a large twin-based longitudinal study. During 17 years of follow-up in TwinsUK and Healthy Ageing Twin Study (HATS), 15,491 hip and lumbar spine dual-energy X-ray absorptiometry (DXA) scans were performed in 7056 twins. Out of these subjects, 2716 female twins aged >35 years with at least two scans separated for >4 years (mean follow-up 9.7 years) were included in this analysis. We used a mixed-effects random-coefficients regression model to predict hip and spine bone mineral density (BMD) values for exact ages of 40, 45, 50, 55, 60, 65, 70, 75, and 80 years, with adjustment for baseline age, weight, height, and duration of hormone replacement therapy. We then estimated heritability of the changes in BMD measures between these age ranges. Heritability estimates for cross-sectional hip and spine BMD were high (ranging between 69% and 88%) at different ages. Heritability of change of BMD was lower and more variable, generally ranging from 0% to 40% for hip and 0% to 70% for spine; between age 40 and 45 years genetic factors explained 39.9% (95% confidence interval [CI], 25%-53%) of variance of BMD loss for total hip, 46.4% (95% CI, 32%-58%) for femoral neck, and 69.5% (95% CI, 59%-77%) for lumbar spine. These estimates decreased with increasing age, and there appeared to be no heritability of BMD changes after the age of 65 years. There was some evidence at the spine for shared genetic effects between cross-sectional and longitudinal BMD. Whereas genetic factors appear to have an important role in bone loss in early postmenopausal women, nongenetic mechanisms become more important determinants of bone loss with advanced age. Copyright © 2012 American Society for Bone and Mineral Research.

  20. 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

    -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...... 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......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...

  1. [Social development of twins: the need for intervention to avoid adverse effects of twin language].

    Science.gov (United States)

    Hayashi, Chisato; Hayakawa, Kazuo; Maeda, Chiho; Nishihara, Reiko; Onoi, Miyuki

    2008-10-01

    Social competence is one of the most important accomplishments of human development, and this skill in human relationships is learned through communication. Therefore, it is considered that delays in language development could be a barrier to building human relationships and social competence. Although it is well known that there are delays in language development in twins compared with that of singletons, little is known about how these linguistic delays affect the development of social competence. Because twin language is a language that is unique to each pair of twins and cannot be understood by either their mother or others, it may be assumed that the social competence of twins who have a twin language is less than that of twins who don't have a twin language. Therefore, in this prospective longitudinal study we also investigated the relationship between twin language and social competence. A mailed questionnaire survey was conducted in 958 mothers as a follow-up of a study conducted in 2004. As a result, 522 respondents returned the questionnaire (53.9%). In this study, we used only 256 twins aged 6- 12-years-old (school-age children) for analysis, excluding those with missing values. Multiple logistic regression analysis was employed. In the second child of twins, a low birth weight, the appearance of twin language and gestosis of the mother were positively related with social unbalance (OR = 1.846, 2.022 and 1.903). On the other hand, with the first child, however, there was no such link. The present results indicate that twin language might influence social competence in school-age children. It has been believed that linguistic intervention is unnecessary, because most twin language disappears spontaneously. However, early intervention, for example linguistic assistance by public health nurses or psychologists and early enrollment in a preschool may be necessary for twins with a twin language, to avoid adverse consequences in social competence at school-age.

  2. Hypoalbuminemia in Donors with Twin Anemia-Polycythemia Sequence : A Matched Case-Control Study

    NARCIS (Netherlands)

    Verbeek, L.; Slaghekke, F.; Hulzebos, C. V.; Oepkes, D.; Walther, F. J.; Lopriore, E.

    2013-01-01

    Objective: To determine the differences in albumin levels between donors and recipients with twin anemia-polycythemia sequence (TAPS). Methods: We included all consecutive monochorionic twins with TAPS with double survivors. Each twin pair was matched for gestational age at birth with 2 control nnon

  3. Hypoalbuminemia in Donors with Twin Anemia-Polycythemia Sequence : A Matched Case-Control Study

    NARCIS (Netherlands)

    Verbeek, L.; Slaghekke, F.; Hulzebos, C. V.; Oepkes, D.; Walther, F. J.; Lopriore, E.

    2013-01-01

    Objective: To determine the differences in albumin levels between donors and recipients with twin anemia-polycythemia sequence (TAPS). Methods: We included all consecutive monochorionic twins with TAPS with double survivors. Each twin pair was matched for gestational age at birth with 2 control

  4. The influence of general anesthesia and surgery on cognition in old age: A twin study

    DEFF Research Database (Denmark)

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

    Introduction: There is a pronounced variation in level of cognitive function and rate of cognitive decline in late life. Results from smaller human and animal studies suggest that exposure to anesthesia may be a risk factor for cognitive impairment. Using a twin design, the objective of the present...... study was to examine whether exposure to anesthesia and surgery is associated with level of cognitive function in middle and old age. Materials and Methods: The study is based on two population-based surveys comprising 8,503 Danish twins aged 45–102 years at study intake during 1995–2001. Through...... linkage to the Danish National Patient Register, we obtained information on surgeries performed in hospitals in Denmark from 1977 and until study intake. Four exposure groups were defined based on type of surgery (major, minor, knee and hip replacement, other). A cognitive test battery consisting of five...

  5. 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...... based on 36 pairs. The probandwise concordance rate for ASD was 95.2 % in monozygotic (MZ) twins (n = 13 pairs) and 4.3 % in dizygotic (DZ) twins (n = 23 pairs). The high MZ and low DZ concordance rate support a genetic aetiology to ASDs....... standard" diagnostic research procedures including diagnostic interview, observation and cognitive examination. Classification was based on DSM-IV-TR criteria. The initial sample included 7,296 same-sexed twin pairs and, after two phases of screening and clinical assessment, the final calculations were...

  6. What Virtual Twins Reveal About General Intelligence and Other Behaviors.

    Science.gov (United States)

    Segal, Nancy L; McGuire, Shirley A; Stohs, Joanne Hoven

    2012-09-01

    The Fullerton Virtual Twin Study has been assessing the behaviors of an unusual sibship since 1982. Virtual twins (VTs) are same-age, unrelated siblings reared together since infancy. They replicate the rearing situation of twins but without the genetic link, enabling direct assessment of shared environmental effects on behavior. An updated analysis of IQ data, based on an increased sample of 142 VT pairs (7.87 years, SD=8.22), is presented. Intraclass correlations of .28 (IQ) and .11 (subtest profile) indicated modest shared environmental influences on intelligence. Findings from the Twins, Adoptees, Peers and Siblings (TAPS) project that studies virtual twins and other kinships are described.

  7. Why Accurate Knowledge of Zygosity is Important to Twins.

    Science.gov (United States)

    Cutler, Tessa L; Murphy, Kate; Hopper, John L; Keogh, Louise A; Dai, Yun; Craig, Jeffrey M

    2015-06-01

    All same-sex dizygotic (DZ) twins and approximately one-third of monozygotic (MZ) twin pairs have separate placentas, making it impossible to use the number of placentas to determine zygosity. Zygosity determination is further complicated because incorrect assumptions are often made, such as that only DZ pairs have two placentas and that all MZ pairs are phenotypically identical. These assumptions, by twins, their families and health professionals, along with the lack of universal zygosity testing for same-sex twins, has led to confusion within the twin community, yet little research has been conducted with twins about their understanding and assumptions about zygosity. We aimed to explore and quantify understanding and assumptions about zygosity using twins attending an Australian twin festival. We recruited 91 twin pairs younger than 18 years of age and their parents, and 30 adult twin pairs who were all uncertain of their zygosity, to complete one pen and paper questionnaire and one online questionnaire about their assumed zygosity, reasons for their assumptions and the importance of accurate zygosity knowledge. Responses were compared with their true zygosity measured using a genetic test. We found a substantial proportion of parents and twins had been misinformed by their own parents or medical professionals, and that knowledge of their true zygosity status provided peace of mind and positive emotional responses. For these reasons we propose universal zygosity testing of same-sex twins as early in life as possible and an increase in education of medical professionals, twins and families of twins about zygosity issues.

  8. College-age twins: university admission policies / twin research: birth weight and neuromotor performance; transfusion syndrome markers; vanishing twins and fetal sex determination; mz twin discordance for wilson's disease / media: big at birth; planned separation of conjoined twins; x factor twins; Cinema: the identical.

    Science.gov (United States)

    Segal, Nancy L

    2014-12-01

    There is a lack of research findings addressing the unique college admissions issues faced by twins and other multiples. The advantages and disadvantage twins face, as reported by college administrators, twins and families are reviewed. Next, recent research addressing twins' birth weight and neuromotor performance, transfusion syndrome markers, the vanishing twin syndrome and monozygotic (MZ) twin discordance for Wilson's disease is described. News items concerning the birth of unusually large twins, the planned separation of conjoined twins, twin participants in the X Factor games and a film, The Identical, are also summarized.

  9. 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

  10. A recent rise in twin birth rates and demographic changes in mothers of twins in South Korea: 2003-2007.

    Science.gov (United States)

    Hur, Yoon-Mi; Song, Tae-Bok

    2009-02-01

    Using the South Korean national live birth data for the years 2003 to 2007, monozygotic (MZ) and dizygotic (DZ) twin birth rates were estimated and analyzed by maternal age, and parents of twins and those of singletons were compared in their level of education. During this period, while the MZ twin birth rate showed no change, the DZ twin birth rate increased up to 9.4 pairs per thousand births. This rate is close to five times as high as the natural DZ twinning rate in the South Korean population. The highest twinning rate occurred among mothers aged 30 to 34 years, followed by mothers aged 25 to 29. These results represented the first evidence for the downward trend in ages of mothers of twins. In each year between 2003 and 2006, percentages of parents who completed college or higher level of education were higher in the twin than in the singleton group, suggesting that the parental socioeconomic level became higher in twins than in singletons. We speculated that these demographic changes occurred because assisted reproductive technology was more easily available among parents of high socioeconomic status. In their sampling strategies, twin researchers should consider our findings of recent changes in demographic characteristics of parents of twins as well as increased DZ twin birth rates.

  11. Resources and pilot results for establishing a Mongolian Twin Register.

    Science.gov (United States)

    Gombojav, Bayasgalan; Damdinbazar, Otgonbayar; Danshiitsoodol, Narandalai; Dagvasumberel, Gonchigsuren; Purevdorj, Erkhembulgan; Gombojav, Enkhtsetseg; Chuluunbaatar, Urjinbadam; Ochir, Chimedsuren; Ichinkhorloo, Purevdorj; Sung, Joohon

    2013-02-01

    Despite the need to provide evidence-based health policy, most developing countries suffer from a lack of resources for sound epidemiologic evidence. Most twin registers have been established in developed countries and there are relatively fewer twin registers in developing countries. Considering the immense potential of twin research, it will be worthwhile to attempt to establish a new twin register in Mongolia, where biomedical studies are still scarce. Our objectives were to initiate the process of establishing a nation-wide twin register in Mongolia, based on a nation-wide, population-based database. With the approval and support of the Ministry of Population Development and Social Welfare of Mongolia, we were able to access an initial list of 411 twin pairs who live in the district of Ulaanbaatar, the capital city of Mongolia. By developing a questionnaire to estimate zygosity, we conducted a pilot survey. Those who registered consisted of 822 individuals or 411 twin pairs (same sex: male - 178; female - 157; different sex - 76), two sets of triplets (same sex: female - 2). The age of twins ranged from 1 to 81 (mean age 7.3 ± 11.3), and 52.4% were males. The first twin survey in Mongolia not only resulted in interim data for the Mongolian Twin Register, but has the potential for establishing a larger register by using the national database. It has been proven possible to establish a twin register for research purposes in Mongolia.

  12. Heritability of regional and global brain structure at the onset of puberty: a magnetic resonance imaging study in 9-year-old twin pairs.

    Science.gov (United States)

    Peper, Jiska S; Schnack, Hugo G; Brouwer, Rachel M; Van Baal, G Caroline M; Pjetri, Eneda; Székely, Eszter; van Leeuwen, Marieke; van den Berg, Stéphanie M; Collins, D Louis; Evans, Alan C; Boomsma, Dorret I; Kahn, René S; Hulshoff Pol, Hilleke E

    2009-07-01

    Puberty represents the phase of sexual maturity, signaling the change from childhood into adulthood. During childhood and adolescence, prominent changes take place in the brain. Recently, variation in frontal, temporal, and parietal areas was found to be under varying genetic control between 5 and 19 years of age. However, at the onset of puberty, the extent to which variation in brain structures is influenced by genetic factors (heritability) is not known. Moreover, whether a direct link between human pubertal development and brain structure exists has not been studied. Here, we studied the heritability of brain structures at 9 years of age in 107 monozygotic and dizygotic twin pairs (N = 210 individuals) using volumetric MRI and voxel-based morphometry. Children showing the first signs of secondary sexual characteristics (N = 47 individuals) were compared with children without these signs, based on Tanner-stages. High heritabilities of intracranial, total brain, cerebellum, and gray and white matter volumes (up to 91%) were found. Regionally, the posterior fronto-occipital, corpus callosum, and superior longitudinal fascicles (up to 93%), and the amygdala, superior frontal and middle temporal cortices (up to 83%) were significantly heritable. The onset of secondary sexual characteristics of puberty was associated with decreased frontal and parietal gray matter densities. Thus, in 9-year-old children, global brain volumes, white matter density in fronto-occipital and superior longitudinal fascicles, and gray matter density of (pre-)frontal and temporal areas are highly heritable. Pubertal development may be directly involved in the decreases in gray matter areas that accompany the transition of our brains from childhood into adulthood.

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

    Science.gov (United States)

    Xu, Chunsheng; Zhang, Dongfeng; Tian, Xiaocao; Wu, Yili; Pang, Zengchang; Li, Shuxia; Tan, Qihua

    2017-02-01

    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 expiratory volume in one second (FEV1), forced vital capacity (FVC), handgrip strength, five-times-sit-to-stand test (FTSST), near visual acuity, and number of teeth lost in 379 complete twin pairs. Bivariate twin models were fitted to estimate the genetic and environmental correlation between physical 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: -1.00, -0.57], and low but significant unique environmental correlation, r E = -0.11 [95% CI: -0.22, -0.01], all in the negative direction. Meanwhile, near visual acuity and cognition also showed unique environmental correlation, r E = 0.16 [95% CI: 0.03, 0.27]. We found no significantly genetic correlation 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 correlation. In contrast, near visual acuity and cognition may positively share part of the unique environmental factors.

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

    Science.gov (United States)

    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-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 environmental influences might account for cognitive change.

  15. What Virtual Twins Reveal About General Intelligence and Other Behaviors

    OpenAIRE

    2012-01-01

    The Fullerton Virtual Twin Study has been assessing the behaviors of an unusual sibship since 1982. Virtual twins (VTs) are same-age, unrelated siblings reared together since infancy. They replicate the rearing situation of twins but without the genetic link, enabling direct assessment of shared environmental effects on behavior. An updated analysis of IQ data, based on an increased sample of 142 VT pairs (7.87 years, SD=8.22), is presented. Intraclass correlations of .28 (IQ) and .11 (subtes...

  16. 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...

  17. 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....... SETTING: Academic clinical research center. PARTICIPANTS: 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). DESIGN: 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...

  18. Virtual Twins: New Findings on Within-Family Environmental Influences on Intelligence.

    Science.gov (United States)

    Segal, Nancy L.

    2000-01-01

    Virtual twins are unrelated siblings of the same age who are reared together from early infancy (UST-SA). Study uses a sample of 90 UST-SA pairs to comparatively assess the similarity of IQ subtest profile correlations for UST-SAs and twin pairs. Findings support explanatory models of intelligence that include genetic factors, demonstrating that…

  19. Chromospheric activity and evolutionary age of the Sun and four solar twins

    CERN Document Server

    Mittag, M; Hempelmann, A; González-Pérez, J N; Schmitt, J H M M

    2016-01-01

    The activity levels of the solar-twin candidates HD 101364 and HD 197027 are measured and compared with the Sun, the known solar twin 18 Sco, and the solar-like star 51 Peg. Furthermore, the absolute ages of these five objects are estimated from their positions in the HR diagram and the evolutionary (relative) age compared with their activity levels. To represent the activity level of these stars, the Mount Wilson S-indices were used. To obtain consistent ages and evolutionary advance on the main sequence, we used evolutionary tracks calculated with the Cambridge Stellar Evolution Code. From our spectroscopic observations of HD 101364 and HD 197027 and based on the established calibration procedures, the respective Mount Wilson S-indices are determined. We find that the chromospheric activity of both stars is comparable with the present activity level of the Sun and that of 18 Sco, at least for the period in consideration. Furthermore, the absolute age of HD 101364, HD 197027, 51 Peg, and 18 Sco are found to ...

  20. 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...

  1. 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.

  2. I. 'Street of twins': multiple births in Cuba II. The Cuban twin registry: an update / twin research reports: cord entanglement; heritability of clubfoot; school separation / twins and twin researchers in the news: reunited at seventy-eight; basketball duo dissolved; delivered holding hands; the better brew; award winners.

    Science.gov (United States)

    Segal, Nancy L; Marcheco-Teruel, Beatriz

    2014-08-01

    I was part of a people-to-people tour of Havana, Cuba during the first week in April 2014. Among the many highlights of that adventure were an informal meeting with Dr Beatriz Marcheco-Teruel, from Cuba's National Center for Medical Genetics, and a visit to the famous 'Street of Twins'. A fortuitous meeting with parents of twins in the fishing town of Jaimanitas was also an extraordinary event. The Cuban experience is followed by summaries of recent twin research, covering umbilical cord entanglement, the heritability of clubfoot and school separation policies for twins. Media reports include twins reunited at age 78, the future of UCLA's twin basketball players, MZ twins born holding hands, a twin conflict over beer and a pair of American Psychological Association honors for Drs Nancy L. Segal and Thomas J. Bouchard, Jr.

  3. Current twin studies in Germany: report on CoSMoS, SOEP, and ChronoS.

    Science.gov (United States)

    Hahn, Elisabeth; Gottschling, Juliana; Spinath, Frank M

    2013-02-01

    This article summarizes the status of three recent German twin studies: CoSMoS, SOEP, and ChronoS. The German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS) is a three-wave longitudinal study of monozygotic and dizygotic twins reared together, and aims to investigate predictors of and influences on school performance. In the first wave of the data collection in 2005, 408 pairs of twins aged between 7 and 11 as well as their parents participated in CoSMoS. The SOEP twin study is an extended twin study, which has combined data from monozygotic and dizygotic twins reared together with additional data from full sibling pairs, mother-child, and grandparent-child dyads who participated in the German Socio-Economic Panel (GSOEP) study. The SOEP twin project comprises about 350 twin and 950 non-twin pairs aged between 17 and 70. Data were collected between 2009 and 2010, with a focus on personality traits, wellbeing, education, employment, income, living situation, life-satisfaction, and several attitudes. The aim of the Chronotype twin study (ChronoS) was to examine genetic and environmental influences on chronotype (morningness and eveningness), coping strategies, and several aspects of the previous SOEP twin project in a sample of 301 twin pairs aged between 19 and 76 years, recruited in 2010 and 2011. Part of the ChronoS twin sample also participated in the earlier SOEP twin study, representing a second wave of assessments. We briefly describe the design and contents of these three studies as well as selected recent findings.

  4. Longitudinal investigation into genetics in the conservation of metabolic phenotypes in Danish and Chinese twins

    DEFF Research Database (Denmark)

    Li, Shuxia; Kyvik, Kirsten Ohm; Duan, Haiping

    2016-01-01

    twin study on long-term stability of metabolic phenotypes in Danish and Chinese twins identified a common pattern of high genetic control over phenotype conservation, and at the same time revealed population-specific patterns of genetic and common environmental regulation on the variance as well...... for 12 years and Chinese twins traced for 7 years. The study covered a relatively large sample of 502 pairs of Danish adult twins with a mean age at intake of 38 years and a total of 181 Chinese adult twin pairs with a mean baseline age of 39.5 years. Bivariate twin models were fitted to the longitudinal...... estimated in both Danish (h2>0.75 except fasting blood glucose) and Chinese (h2>0.72 except blood pressure) twins; moderate to high genetic contribution to phenotype variation at the two time points were also estimated except for the low genetic regulation on glucose in Danish and on blood pressure...

  5. Education in time: cohort differences in educational attainment in African-American twins.

    Directory of Open Access Journals (Sweden)

    Sarah L Szanton

    Full Text Available OBJECTIVES: Educational opportunities for African-Americans expanded throughout the 20(th century. Twin pairs are an informative population in which to examine changes in educational attainment because each twin has the same parents and childhood socioeconomic status. We hypothesized that correlation in educational attainment of older twin pairs would be higher compared to younger twin pairs reflecting changes in educational access over time and potentially reflecting a "ceiling effect" associated with Jim Crow laws and discrimination. METHODOLOGY AND PRINCIPAL FINDINGS: We used data from 211 same-sex twin pairs (98 identical, 113 fraternal in the Carolina African-American Twin Study of Aging who were identified through birth records. Participants completed an in-person interview. The twins were predominantly female (61%, with a mean age of 50 years (SD = 0.5. We found that older age groups had a stronger intra-twin correlation of attained educational level. Further analysis across strata revealed a trend across zygosity, with identical twins demonstrating more similar educational attainment levels than did their fraternal twin counterparts, suggesting a genetic influence. DISCUSSION: These findings suggest that as educational opportunities broadened in the 20th century, African-Americans gained access to educational opportunities that better matched their individual abilities.

  6. CoSMoS and TwinPaW: initial report on two new German twin studies.

    Science.gov (United States)

    Spinath, Frank M; Wolf, Heike

    2006-12-01

    After briefly recapitulating two earlier German twin studies (BiLSAT and GOSAT), we present two new German twin studies with a longitudinal perspective: CoSMoS and TwinPaW. The twin study on Cognitive ability, Self-reported Motivation and School performance (CoSMoS) aims to investigate predictors and influences of school performance in a genetically sensitive design, beginning with children in late elementary school. The Twin study on Personality And Wellbeing (TwinPaW) focuses on adult personality and its relation to physical health as well as health-related behavior in an adult sample of twins. Both studies are characterized by an effort to recruit new large twin samples through a novel recruitment procedure aimed at reducing self-selective sampling. In two German federal states, contact information on persons born on the same day and with the same name was retrieved from record sections. From the resulting pool of more than 36,000 addresses we contacted approximately 2000 parents of twins aged 9 and 10 for CoSMoS, as well as 2000 adult twin pairs for TwinPaW by telephone and mail. Personal contact by telephone proved to be more efficient with agreement rates of 63% in the children sample and 65% in the adult sample. In this article we briefly describe the rationale and the study aims of CoSMoS and TwinPaW as well as the characteristics of the sample we have recruited so far.

  7. 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

    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......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...... 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...

  8. Heritability of psoriasis in a large twin sample

    DEFF Research Database (Denmark)

    Lønnberg, Ann Sophie; Skov, L; 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......, 4.1% of the men and 4.2% of the women had a lifetime history of psoriasis. The probandwise concordance for psoriasis was larger in monozygotic than in dizygotic twins, 0.33 vs. 0.17. Genetic factors explained 68% (60-75%) of the variation in the susceptibility to psoriasis, whereas the rest...

  9. 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...... direction. We conclude that genetic factors contribute significantly to the individual differences in common indicators of daily functioning (FEV1, handgrip, and FTSST). FEV1 and FVC were genetically and environmentally correlated. Pulmonary function and FTSST may share similar sets of genes...

  10. A Pair of Identical Twins Discordant for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Differ in Physiological Parameters and Gut Microbiome Composition

    Science.gov (United States)

    Giloteaux, Ludovic; Hanson, Maureen R.; Keller, Betsy A.

    2016-01-01

    Patient: Male, 34 Final Diagnosis: ME/CFS Symptoms: Exertion intolerance • loss of functional capacity • pain • severe fatigue Medication: — Clinical Procedure: Cardiopulmonary exercise test Specialty: Sports Medicine Objective: Unknown ethiology Background: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) present with profound fatigue, flu-like symptoms, pain, cognitive impairment, orthostatic intolerance, post-exertional malaise (PEM), and exacerbation of some or all of the baseline symptoms. Case Report: We report on a pair of 34-year-old monozygotic twins discordant for ME/CFS, with WELL, the non-affected twin, and ILL, the affected twin. Both twins performed a two-day cardiopulmonary exercise test (CPET), preand post-exercise blood samples were drawn, and both provided stool samples for biochemical and molecular analyses. At peak exertion for both CPETs, ILL presented lower VO2peak and peak workload compared to WELL. WELL demonstrated normal reproducibility of VO2@ventilatory/anaerobic threshold (VAT) during CPET2, whereas ILL experienced an abnormal reduction of 13% in VAT during CPET2. A normal rise in lactate dehydrogenase (LDH), creatine kinase (CK), adrenocorticotropic hormone (ACTH), cortisol, creatinine, and ferritin content was observed following exercise for both WELL and ILL at each CPET. ILL showed higher increases of resistin, soluble CD40 ligand (sCD40L), and soluble Fas ligand (sFasL) after exercise compared to WELL. The gut bacterial microbiome and virome were examined and revealed a lower microbial diversity in ILL compared to WELL, with fewer beneficial bacteria such as Faecalibacterium and Bifidobacterium, and an expansion of bacteriophages belonging to the tailed dsDNA Caudovirales order. Conclusions: Results suggest dysfunctional immune activation in ILL following exercise and that prokaryotic viruses may contribute to mucosal inflammation and bacterial dysbiosis. Therefore, a two-day CPET and molecular

  11. A Twin Protection Effect? Explaining Twin Survival Advantages with a Two-Process Mortality Model.

    Science.gov (United States)

    Sharrow, David J; Anderson, James J

    2016-01-01

    Twin studies that focus on the correlation in age-at-death between twin pairs have yielded important insights into the heritability and role of genetic factors in determining lifespan, but less attention is paid to the biological and social role of zygosity itself in determining survival across the entire life course. Using data from the Danish Twin Registry and the Human Mortality Database, we show that monozygotic twins have greater cumulative survival proportions at nearly every age compared to dizygotic twins and the Danish general population. We examine this survival advantage by fitting these data with a two-process mortality model that partitions survivorship patterns into extrinsic and intrinsic mortality processes roughly corresponding to acute, environmental and chronic, biological origins. We find intrinsic processes confer a survival advantage at older ages for males, while at younger ages, all monozygotic twins show a health protection effect against extrinsic death akin to a marriage protection effect. While existing research suggests an increasingly important role for genetic factors at very advanced ages, we conclude that the social closeness of monozygotic twins is a plausible driver of the survival advantage at ages <65.

  12. Genetic Factors Explain Variation in the Age at Onset of Psoriasis

    DEFF Research Database (Denmark)

    Lønnberg, Ann Sophie; Skov, Lone; Duffy, David Lorenzo

    2016-01-01

    The aim of this study was to determine the age at onset of psoriasis in a population-based twin sample. Questionnaire-data in 10,725 twin pairs, 20-71 years of age, from the Danish Twin Registry, was collected, and analysed using survival regression analysis. Median age at onset was 25 and 28 years...

  13. 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.

  14. Genetic Variance for Autism Screening Items in an Unselected Sample of Toddler-Age Twins

    Science.gov (United States)

    Stilp, Rebecca L. H.; Gernsbacher, Morton Ann; Schweigert, Emily K.; Arneson, Carrie L.; Goldsmith, H. Hill

    2010-01-01

    Objective: Twin and family studies of autistic traits and of cases diagnosed with autism suggest high heritability; however, the heritability of autistic traits in toddlers has not been investigated. Therefore, this study's goals were (1) to screen a statewide twin population using items similar to the six critical social and communication items…

  15. 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.

  16. 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.

  17. 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

    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 ......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 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...... 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....

  18. 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...

  19. Peer Network Overlap in Twin, Sibling, and Friend Dyads

    Science.gov (United States)

    McGuire, Shirley; Segal, Nancy L.

    2013-01-01

    Research suggests that sibling–peer connections are important for understanding adolescent problem behaviors. Using a novel behavioral genetic design, the current study investigated peer network overlap in 300 child–child pairs (aged 7-13 years) in 5 dyad types: monozygotic (MZ), dizygotic twins, full siblings (FSs), friend pairs, and virtual…

  20. Better stay together: pair bond duration increases individual fitness independent of age-related variation

    OpenAIRE

    Sánchez-Macouzet, Oscar; Rodríguez, Cristina; Drummond, Hugh

    2014-01-01

    Prolonged pair bonds have the potential to improve reproductive performance of socially monogamous animals by increasing pair familiarity and enhancing coordination and cooperation between pair members. However, this has proved very difficult to test robustly because of important confounds such as age and reproductive experience. Here, we address limitations of previous studies and provide a rigorous test of the mate familiarity effect in the socially monogamous blue-footed booby, Sula neboux...

  1. 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 egg

  2. [Heritability analysis on serum lipids of adult twins in Qingdao City

    DEFF Research Database (Denmark)

    Lan, Jinfeng; Pang, Zengchang; Wang, Shaojie

    2010-01-01

    OBJECTIVE: To study the level and heritability of serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and triglycerides (TG) in adult twins sampled from Qingdao City of China. METHODS: 316 pairs of healthy twin aged 18 to 60 years...

  3. Math Fluency Is Etiologically Distinct from Untimed Math Performance, Decoding Fluency, and Untimed Reading Performance: Evidence from a Twin Study

    Science.gov (United States)

    Petrill, Stephen; Logan, Jessica; Hart, Sara; Vincent, Pamela; Thompson, Lee; Kovas, Yulia; Plomin, Robert

    2012-01-01

    The authors examined whether math fluency was independent from untimed math and from reading using 314 pairs of school-aged twins drawn from the Western Reserve Reading and Math Projects. Twins were assessed through a 90-min home visit at approximately age 10 and were reassessed in their homes approximately 1 year later. Results suggested that the…

  4. Math Fluency Is Etiologically Distinct from Untimed Math Performance, Decoding Fluency, and Untimed Reading Performance: Evidence from a Twin Study

    Science.gov (United States)

    Petrill, Stephen; Logan, Jessica; Hart, Sara; Vincent, Pamela; Thompson, Lee; Kovas, Yulia; Plomin, Robert

    2012-01-01

    The authors examined whether math fluency was independent from untimed math and from reading using 314 pairs of school-aged twins drawn from the Western Reserve Reading and Math Projects. Twins were assessed through a 90-min home visit at approximately age 10 and were reassessed in their homes approximately 1 year later. Results suggested that the…

  5. 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.

  6. Hypoalbuminemia in Donors with Twin-Twin Transfusion Syndrome

    NARCIS (Netherlands)

    Verbeek, L.; Middeldorp, J. M.; Hulzebos, C. V.; Oepkes, D.; Walther, F. J.; Lopriore, E.

    2013-01-01

    Objective: To estimate the differences in albumin levels between donors and recipients with twin-twin transfusion syndrome (TTTS). Methods: We performed a matched case-control study including twin pairs with TTTS treated conservatively (conservative group) or with fetoscopic laser surgery (laser gro

  7. Twin-twin Transfusion Syndrome with a Single Ectopic Kidney in a Twin Donor. Case Presentation

    Directory of Open Access Journals (Sweden)

    Gerardo Rogelio Robaina Castellanos

    2016-10-01

    Full Text Available Twin-twin Transfusion Syndrome presents more frequently in diamniotic monochromic twins. In advanced stages and without prenatal intervention, is associated to high rates of peri natal mortality and neurological sequel in the survivors. It is presented a case of a pair of twins with severe depression at birth in which it was diagnosed a Twin-twin Transfusion Syndrome, later confirmed with the presence of anemia in the donor twin and polycythemia in the receptor twin. Both twins had an unfavourable evolution with an early neonatal death. Necropsy findings were comparable with secondary damage to the syndrome, with the particularity that both had evidences of pulmonary infection and a renal malformation in the donor twin which is not included in the proper malformations of this syndrome. The objective of this work is to point out the essential elements for the diagnosis and antenatal treatment for this disease through the peculiarities of the presented case.

  8. 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...

  9. Twinning and Multiple Birth Rates According to Maternal Age in the City of São Paulo, Brazil: 2003-2014.

    Science.gov (United States)

    Otta, Emma; Fernandes, Eloisa de S; Acquaviva, Tiziana G; Lucci, Tania K; Kiehl, Leda C; Varella, Marco A C; Segal, Nancy L; Valentova, Jaroslava V

    2016-12-01

    The present study investigates the twinning rates in the city of São Paulo, Brazil, during the years 2003-2014. The data were drawn from the Brazilian Health Department database of Sistema de Informações de Nascidos Vivos de São Paulo-SINASC (Live Births Information System of São Paulo). In general, more information is available on the incidence of twinning in developed countries than in developing ones. A total of 24,589 twin deliveries and 736 multiple deliveries were registered in 140 hospitals of São Paulo out of a total of 2,056,016 deliveries during the studied time period. The overall average rates of singleton, twin, and multiple births per 1,000 maternities (‰) were 987.43, 11.96 (dizygotic (DZ) rate was 7.15 and monozygotic (MZ) 4.42), and 0.36, respectively. We further regressed maternal age and historical time period on percentage of singleton, twin, and multiple birth rates. Our results indicated that maternal age strongly positively predicted twin and multiple birth rates, and negatively predicted singleton birth rates. The historical time period also positively, although weakly, predicted twin birth rates, and had no effect on singleton or multiple birth rates. Further, after applying Weinberg's differential method, we computed regressions separately for the estimated frequencies of DZ and MZ twin rates. DZ twinning was strongly positively predicted by maternal age and, to a smaller degree, by time period, while MZ twinning increased marginally only with higher maternal age. Factors such as increasing body mass index or air pollution can lead to the slight historical increase in DZ twinning rates. Importantly, consistent with previous cross-cultural and historical research, our results support the existence of an age-dependent physiological mechanism that leads to a strong increase in twinning and multiple births, but not singleton births, among mothers of higher age categories. From the ultimate perspective, twinning and multiple births in

  10. Colour pairs for constraining the age and metallicity of stellar populations

    OpenAIRE

    2007-01-01

    Using a widely used stellar population synthesis model, we study the ability of using pairs of AB system colours to break the well-known stellar age--metallicity degeneracy and give constraints on the two stellar-population parameters (age and metallicity). The relative age and metallicity sensitivities of AB system colours that relate to u, B, g, V, r, R, i, I, z, J, H, and K bands are presented, and the abilities of various colour pairs for breaking the age--metallicity degeneracy are quant...

  11. The Twin Interdisciplinary Neuroticism Study

    NARCIS (Netherlands)

    Riese, Harriette; Rijsdijk, Fruehling V.; Snieder, Harold; Ormel, Johan

    The Twin Interdisciplinary Neuroticism Study (TWINS) is a three-wave study including >800 twin pairs from the northern part of the Netherlands. The aim of the study is to unravel why neuroticism reflects vulnerability to mental disorders. In this study, we focus on possible mechanisms underlying

  12. Age moderates non-genetic influences on the initiation of cannabis use: a twin-sibling study in Dutch adolescents and young adults.

    Science.gov (United States)

    Distel, Marijn A; Vink, Jacqueline M; Bartels, Meike; van Beijsterveldt, Catharina E M; Neale, Michael C; Boomsma, Dorret I

    2011-09-01

    To examine the heritability of cannabis initiation, the influence of a possible twin-specific environment and the influence of age on the effects of genes and environment in Dutch adolescents and young adults. Genetic structural equation modelling was used to partition the variance in the liability to cannabis initiation into genetic and environmental components. All participants were registered with the Netherlands Twin Register. A total of 6,208 twins (age 13-20) and 1,545 siblings (age 11-25) from 3,503 families participated in this study. Self-reported cannabis use was assessed prospectively with the Dutch Health Behavior Questionnaire. At the median age of the sample (16.5), genetic factors explained 40% of the individual differences in liability to cannabis initiation. Twins resembled each other more than non-twin siblings, which could not be attributed to the age difference between non-twin siblings. Environmental influences increased with age. This increase applied to environmental factors shared by twins (47% of the variance), environmental factors shared by twins and siblings (24%) and environmental factors unique to an individual (13%). The heritability of the liability for cannabis initiation is higher in adolescents than in young adults due to a larger contribution of environmental factors in young adults. This is due mainly to environmental factors only shared by twins and those shared by all offspring growing up in the same family, but the contribution of environmental factors specific to individuals is also larger in young adults. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.

  13. Twin delivery: how should the second twin be delivered?

    Science.gov (United States)

    Olofsson, P; Rydhström, H

    1985-11-01

    In a series of 803 pairs of twins born between 1973 and 1982, 0.33% of second twins were delivered by cesarean section after vaginal delivery of the first twin. During the last year the frequency has increased to 7%, calling attention to the problem of declining obstetric skills and experience. This has caused us to update the routines of intrapartum management of twin gestations. In the present program only commonly available obstetric techniques are used. The potentially hazardous twin delivery is excluded from a trial of vaginal delivery. Hopefully, the program will help other obstetricians to decide in favor of vaginal delivery in selected twin gestations.

  14. Familial and Special Twin Influences on Cigarette Use Initiation.

    Science.gov (United States)

    Bares, Cristina B; Maes, Hermine H; Kendler, Kenneth S

    2017-04-01

    Shared experiences within families play an important role in the initiation of cigarette use among adolescents. Behavioral genetic studies using various samples have implicated that the shared environment that twins experience is an important source of influence on whether adolescents initiate cigarette use. Whether the special twin environment, in addition to the shared environment, contributes significantly to making twin siblings more similar in cigarette initiation, and whether the influence of the special twin environment persists into adulthood, is less clear. Data for this study came from the National Longitudinal Survey of Adolescent Health. Twin, full-, and half-sibling pairs between the ages of 12 and 33 were separated into three age groups, with about 3,000 individuals in each age group. The proportion of variance in cigarette use initiation explained by genetic, shared, special twin, and unique environmental factors were examined. The results of separate age-moderated univariate variance decomposition models indicate that the special twin environment does not significantly contribute to the variance in cigarette use initiation in adolescence or young adulthood. Factors shared by individuals in a family, but that are not specific to being a twin, are important in determining whether adolescents will initiate the use of cigarettes.

  15. Genetic influences on Chronic Obstructive Pulmonary Disease - a twin study.

    Science.gov (United States)

    Ingebrigtsen, Truls; Thomsen, Simon F; Vestbo, Jørgen; van der Sluis, Sophie; Kyvik, Kirsten O; Silverman, Edwin K; Svartengren, Magnus; Backer, Vibeke

    2010-12-01

    Genes that contribute to the risk of developing Chronic Obstructive Pulmonary Disease (COPD) have been identified, but an attempt to accurately quantify the total genetic contribution to COPD has to our knowledge never been conducted. Hospital discharge diagnoses data on COPD were analysed in 22,422 Danish twin pairs, 20-71 years of age. The analyses were replicated in a population of 27,668 Swedish twin pairs, 45-108 years of age. A Cox-regression model was applied to the discordant time from the age at first hospital admission for COPD in the co-twin of an affected twin. Latent factor models were used to estimate genetic and environmental effects. The probandwise concordance rate for COPD was higher in monozygotic (MZ) than in dizygotic (DZ) twins, 0.19 vs. 0.07 (p = 0.08) in the Danish population, and 0.20 vs. 0.08 (p = 0.006) in the Swedish population. After adjusting for sex, smoking and age at first hospital admission the risk of developing COPD in the co-twin of an affected twin was higher in MZ than in DZ twins, with hazards ratio 4.3 (95% confidence interval 1.2-15.8, p = 0.03) in Danish twins and 3.4 (1.5-7.7, p = 0.004) in Swedish twins. According to the most parsimonious model, additive genetic factors explained 63% (46-77%) of the individual COPD-susceptibility in the Danish population and 61% (48-72%) in the Swedish population. The susceptibility to develop severe COPD, as defined by hospitalizations, is strongly influenced by genetic factors. Approximately 60% of the individual susceptibility can be explained by genetic factors. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. 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).

  17. Better stay together: pair bond duration increases individual fitness independent of age-related variation

    Science.gov (United States)

    Sánchez-Macouzet, Oscar; Rodríguez, Cristina; Drummond, Hugh

    2014-01-01

    Prolonged pair bonds have the potential to improve reproductive performance of socially monogamous animals by increasing pair familiarity and enhancing coordination and cooperation between pair members. However, this has proved very difficult to test robustly because of important confounds such as age and reproductive experience. Here, we address limitations of previous studies and provide a rigorous test of the mate familiarity effect in the socially monogamous blue-footed booby, Sula nebouxii, a long-lived marine bird with a high divorce rate. Taking advantage of a natural disassociation between age and pair bond duration in this species, and applying a novel analytical approach to a 24 year database, we found that those pairs which have been together for longer establish their clutches five weeks earlier in the season, hatch more of their eggs and produce 35% more fledglings, regardless of age and reproductive experience. Our results demonstrate that pair bond duration increases individual fitness and further suggest that synergistic effects between a male and female's behaviour are likely to be involved in generating a mate familiarity effect. These findings help to explain the age- and experience-independent benefits of remating and their role in life-history evolution. PMID:24827435

  18. Genetic contribution to rate of change in functional abilities among Danish twins aged 75 years or more

    DEFF Research Database (Denmark)

    Christensen, Kaare; Gaist, David; Vaupel, James W

    2002-01-01

    -based sample of 2,401 Danish twins aged 75 years or more. The survivors were recontacted after 2 years and again after 4 years. Consistent mean-level declines, high within-person correlations over time, and substantial heritability in the female sample were observed for functional abilities. Nonetheless......, structural-equation analyses revealed only a very modest and nonsignificant heritability for rate of change in functional abilities: 16% (95% confidence interval: 0, 35) for women and 9% (95% confidence interval: 0, 44) for men. This study had a large initial sample size, high participation rates......In a previous cross-sectional study of twins, the authors found evidence of a substantial genetic influence on functional abilities among elderly women. It has been suggested that rate of change in functional abilities over time could underlie such findings and that rate-of-change phenotypes may...

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

    CERN Document Server

    Maia, M Tucci; Meléndez, J; Bedell, M; Bean, J L; Asplund, M

    2016-01-01

    Solar twins are stars with similar stellar (surface) parameters to the Sun that can have a wide range of ages. This provide an opportunity to analyze the variation of their chemical abundances with age. Nissen (2015) recently suggested that the abundances of the s-process element Y and the $\\alpha$-element Mg could be used to estimate stellar ages. 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. 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. The [Y/Mg] ratio shows a strong correlation with age. It has a slope of -0.041$\\pm$0.001 dex/Gyr and a significance of 41 $\\sigma$. Th...

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

    Science.gov (United States)

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

    2015-06-01

    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 clinical care. The cohort was assembled in the early 1960s with identification of approximately 16,000 twin pairs, review of service records, a brief mailed questionnaire assessing zygosity, and a health survey largely comparable to questionnaires used at that time with Scandinavian twin registries. Subsequent large-scale data collection occurred in 1974, 1985 and 1998, repeating the health survey and including information on education, employment history and earnings. Self-reported data have been supplemented with mortality, disability and medical data through record linkage. Potential collaborators should access the study website [http://www.iom.edu/Activities/Veterans/TwinsStudy.aspx] or e-mail the Medical Follow-up Agency at [Twins@nas.edu]. Questionnaire data are being prepared for future archiving with the National Archive of Computerized Data on Aging (NACDA) at the Inter-University Consortium for Political and Social Research (ICPSR), University of Michigan, MI.

  1. The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima. Fundamental parameters from PIONIER, NACO, and UVES observations

    Science.gov (United States)

    Kervella, P.; Mérand, A.; Ledoux, C.; Demory, B.-O.; Le Bouquin, J.-B.

    2016-10-01

    The nearby red dwarf binary GJ65 AB (UV+BL Ceti, M5.5Ve+M6Ve) is a cornerstone system to probe the physics of very low-mass stars. The radii of the two stars are currently known only from indirect photometric estimates, however, and this prevents us from using GJ65 AB as calibrators for the mass-radius (M-R) relation. We present new interferometric measurements of the angular diameters of the two components of GJ65 with the VLTI/PIONIER instrument in the near-infrared H band: θUD(A) = 0.558 ± 0.008 ± 0.020 mas and θUD(B) = 0.539 ± 0.009 ± 0.020 mas. They translate into limb-darkened angular diameters of θLD(A) = 0.573 ± 0.021 mas and θLD(B) = 0.554 ± 0.022 mas. Based on the known parallax, the linear radii are R(A) = 0.165 ± 0.006 R⊙ and R(B) = 0.159 ± 0.006 R⊙ (σ(R) /R = 4%). We searched for the signature of flares and faint companions in the interferometric visibilities and closure phases, but we did not identify any significant signal. We also observed GJ65 with the VLT/NACO adaptive optics and refined the orbital parameters and infrared magnitudes of the system. We derived masses for the two components of m(A) = 0.1225 ± 0.0043 M⊙ and m(B) = 0.1195 ± 0.0043 M⊙ (σ(m) /m = 4%). To derive the radial and rotational velocities of the two stars as well as their relative metallicity with respect to Proxima, we also present new individual UVES high-resolution spectra of the two components. Placing GJ65 A and B in the mass-radius diagram shows that their radii exceed expectations from recent models by 14 ± 4% and 12 ± 4%, respectively. Following previous theories, we propose that this discrepancy is caused by the inhibition of convective energy transport by a strong internal magnetic field generated by dynamo effect in these two fast-rotating stars. A comparison with the almost identical twin Proxima, which is rotating slowly, strengthens this hypothesis because the radius of Proxima does not appear to be inflated compared to models. Based on

  2. Heritability of retinal vascular fractals: a twin study

    DEFF Research Database (Denmark)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line

    Purpose: To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension. Methods: This was a cross-sectional study of 50-degree, disc-centred fundus photographs from 59 monozygotic and 55 dizygotic, same-sex twin pairs aged 20-46 years....... 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...

  3. Association between physical and motor development in childhood: a longitudinal study of Japanese twins.

    Science.gov (United States)

    Silventoinen, Karri; Pitkäniemi, Janne; Latvala, Antti; Kaprio, Jaakko; Yokoyama, Yoshie

    2014-06-01

    Length and weight in infancy are associated with neurodevelopment, but less is known about growth in other anthropometric measures. In this study we analyzed how the development in length, weight, head circumference, and chest circumference over infancy is associated with motor development in early childhood, using a twin study design. Information on physical development over infancy and the age at achievement of eight developmental milestones over early childhood was collected for 370 Japanese twin pairs. Linear mixed models were used to analyze how physical development is associated with motor development between individual twins, as well as within twin pairs, adjusting the results for shared maternal and postnatal environmental factors. Delayed motor development was associated with smaller body size over infancy, and we also found some suggestive evidence that it was associated with catch-up growth as well. When studying the associations within twin pairs discordant for motor development, similar associations were found. However, chest circumference showed the most robust association within discordant twin pairs. Smaller body size and rapid catch-up growth are associated with delayed motor development. When studying these associations within twin pairs and thus adjusting the results for gestational age as well as many other maternal and postnatal environmental factors, chest circumference showed the most robust association. Chest circumference, rarely used in developed countries, can offer additional information on prenatal conditions relevant for further motor development not achieved by more traditional anthropometric measures.

  4. The Nature of Covariation between Autistic Traits and Clumsiness: A Twin Study in a General Population Sample

    Science.gov (United States)

    Moruzzi, Sara; Ogliari, Anna; Ronald, Angelica; Happe, Francesca; Battaglia, Marco

    2011-01-01

    While social impairment, difficulties with communication, and restricted repetitive behaviors are central features of Autism Spectrum Disorders, physical clumsiness is a commonly co-occurring feature. In a sample of 398 twin pairs (aged 8-17 years) from the Italian Twin Registry we investigated the nature of the co-variation between a psychometric…

  5. 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.

  6. Genetic influence on bone mineral density in Korean twins and families: the healthy twin study.

    Science.gov (United States)

    Park, J-H; Song, Y-M; Sung, J; Lee, K; Kim, Y S; Park, Y S

    2012-04-01

    Bone mineral density (BMD), a representative marker of osteoporosis risk, is found to be highly heritable in this Korean study, which is very consistent with the findings in Western populations. This finding strongly supports that genetic factors are significant determinants of osteoporosis risk along with individual biological and behavioral factors. Although genetic factors are known to contribute significantly to variations in BMD in Western populations, such an association has not been fully evaluated in an Asian population. This study was conducted to determine the role of genetic factors on BMD in Korean population. The study participants were 2,728 men and women consisting of 497 monozygotic (MZ) twin pairs, 119 dizygotic (DZ) twin pairs, and 1,496 first-degree relatives from the Healthy Twin Study. BMD was measured using dual-energy X-ray absorptiometry. Quantitative genetic analysis based on a variance decomposition model was performed. Age and the measured covariates accounted for 17~61% of the variation in BMD, depending on the sites of measurement. After accounting for the covariate effects, the heritability of BMD at the whole body, thoracic and lumbar spine, whole ribs, whole pelvis, whole arms, and whole legs were 0.76, 0.72, 0.73, 0.71, 0.51, and 0.75, respectively. The pair-wise correlation of BMD was the highest within MZ twin pairs, followed by DZ twin pairs, sibling pairs, and parents-child pairs. Cross-trait correlation analysis revealed a positive genetic correlation between BMDs at different sites, ranging from 0.80 (arm and leg BMD) to 0.50 (pelvis and arm BMD). The high heritability of BMD in this Korean population similar to those found in Western populations and the significant common genetic basis between BMDs at different sites strongly supports a significant role of genetic determinants on the risk of osteoporosis.

  7. 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.......36-2.72), P = 0.000; and atopic dermatitis, HR = 1.44 (1.02-2.06), P = 0.041 were significant risk factors for urticaria. After adjustment for sex and age at onset of urticaria in the index twin, the risk of urticaria was increased in MZ cotwins relative to DZ cotwins, HR = 1.42 (0.63-3.18), P = 0...

  8. Conjoined Twins

    Science.gov (United States)

    ... sites of conjoined twins. Abdomen. Omphalopagus (om-fuh-LOP-uh-gus) twins are joined near the bellybutton. ... brain tissue. Head and chest. Cephalopagus (sef-uh-LOP-uh-gus) twins are joined at the face ...

  9. Dramatically different dizygotic twins: will we include them in Research? Twin research reviews: congenital anomalies, mirror-image effects in conjoined twins, older mothers of twins; Twin statistics: 'Massachusetts, land of twins'; Tribute: Dr Victor A. McKusick.

    Science.gov (United States)

    Segal, Nancy L

    2008-10-01

    The increased frequency of interracial marriage is a likely source of unusual-looking dizygotic (DZ) twins. Some members of DZ twin pairs born to mixed-race couples inherit very different physical features from their parents. This raises several questions, such as: Will researchers wish to include such twins in their ongoing studies? Next, new twin research concerned with congenital anomalies, mirror-image effects in conjoined twins and older mothers of twins will be reviewed. New statistics on twinning rates in Massachusetts will also be summarized, followed by a tribute to the late medical geneticist Dr. Victor A. McKusick.

  10. Genetic contribution to rate of change in functional abilities among Danish twins aged 75 years or more.

    Science.gov (United States)

    Christensen, Kaare; Gaist, David; Vaupel, James W; McGue, Matt

    2002-01-15

    In a previous cross-sectional study of twins, the authors found evidence of a substantial genetic influence on functional abilities among elderly women. It has been suggested that rate of change in functional abilities over time could underlie such findings and that rate-of-change phenotypes may have an even larger genetic component than "level" phenotypes (e.g., functional abilities per se). If so, rate-of-change phenotypes could be more powerful than level phenotypes in studies aimed at identifying specific polymorphisms of importance for aging. In 1995, the authors assessed a population-based sample of 2,401 Danish twins aged 75 years or more. The survivors were recontacted after 2 years and again after 4 years. Consistent mean-level declines, high within-person correlations over time, and substantial heritability in the female sample were observed for functional abilities. Nonetheless, structural-equation analyses revealed only a very modest and nonsignificant heritability for rate of change in functional abilities: 16% (95% confidence interval: 0, 35) for women and 9% (95% confidence interval: 0, 44) for men. This study had a large initial sample size, high participation rates, and a valid and reliable measure of rate of change in a phenotype that had previously shown substantial heritability in cross-sectional analyses in the same twin population. Still, the present study revealed only a modest and nonsignificant genetic influence on rate of change, which suggests that detection of polymorphisms influencing rate of change in functional abilities among the elderly may prove to be difficult.

  11. 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.

  12. [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.

  13. The first large population based twin study of coeliac disease

    Science.gov (United States)

    Greco, L; Romino, R; Coto, I; Di Cosmo, N; Percopo, S; Maglio, M; Paparo, F; Gasperi, V; Limongelli, M G; Cotichini, R; D'Agate, C; Tinto, N; Sacchetti, L; Tosi, R; Stazi, M A

    2002-01-01

    Background and aims: The genetic load in coeliac disease has hitherto been inferred from case series or anecdotally referred twin pairs. We have evaluated the genetic component in coeliac disease by estimating the concordance rate for the disease among twin pairs in a large population based study. Methods: The Italian Twin Registry was matched with the membership lists of a patient support group. Forty seven twin pairs were recruited and screened for antiendomysial (EMA) and antihuman-tissue transglutaminase (anti-tTG) antibodies; zygosity was verified by DNA fingerprinting and twins were typed for HLA class II DRB1 and DQB1 molecules. Results: Concordance rates for coeliac disease differ significantly between monozygotic (MZ) (0.86 probandwise and 0.75 pairwise) and dizygotic (DZ) (0.20 probandwise and 0.11 pairwise) twins. This is the highest concordance so far reported for a multifactorial disease. A logistic regression model, adjusted for age, sex, number of shared HLA haplotypes, and zygosity, showed that genotypes DQA1*0501/DQB1*0201 and DQA1*0301/DQB1*0302 (encoding for heterodimers DQ2 and DQ8, respectively) conferred to the non-index twin a risk of contracting the disease of 3.3 and 1.4, respectively. The risk of being concordant for coeliac disease estimated for the non-index twin of MZ pairs was 17 (95% confidence interval 2.1–134), independent of the DQ at risk genotype. Conclusion: This study provides substantial evidence for a very strong genetic component in coeliac disease, which is only partially due to the HLA region. PMID:11950806

  14. Twinning and heteropaternity in chimpanzees (Pan troglodytes).

    Science.gov (United States)

    Ely, John J; Frels, William I; Howell, Sue; Izard, M Kay; Keeling, Michale E; Lee, D Rick

    2006-05-01

    Unlike monozygotic (MZ) twins, dizygotic (DZ) twins develop from separate ova. The resulting twins can have different sires if the fertilizing sperm comes from different males. Routine paternity testing of a pair of same-sexed chimpanzee twins born to a female housed with two males indicated that the twins were sired by two different males. DNA typing of 22 short-tandem repeat (STR) loci demonstrated that these twins were not MZ twins but heteropaternal DZ twins. Reproductive data from 1926-2002 at five domestic chimpanzee colonies, including 52 twins and two triplets in 1,865 maternities, were used to estimate total twinning rates and the MZ and DZ components. The average chimpanzee MZ twinning rate (0.43%) equaled the average human MZ rate (0.48%). However, the chimpanzee DZ twinning rate (2.36%) was over twice the human average, and higher than all but the fertility-enhanced human populations of Nigeria. Similarly high twinning rates among African chimpanzees indicated that these estimates were not artifacts of captivity. Log-linear analyses of maternal and paternal effects on recurrent twinning indicated that females who twinned previously had recurrence risks five times greater than average, while evidence for a paternal twinning effect was weak. Chimpanzee twinning rates appear to be elevated relative to corresponding estimated human rates, making twinning and possibly heteropaternity more important features of chimpanzee reproductive biology than previously recognized.

  15. Growing old but not growing apart: twin similarity in the latter half of the lifespan.

    Science.gov (United States)

    McGue, Matt; Christensen, Kaare

    2013-01-01

    While a substantial amount of behavioral genetic research has helped to characterize developmental trends in twin similarity in early life, relatively little is known about changes in twin similarity with age in adulthood. We investigated age moderation of twin similarity for a composite measure of cognitive ability, depression symptomatology and hand grip strength in a cross-sectional sample of 2,332 like-sex pairs of Danish twins age 46-96 years. All three outcomes were strongly correlated with age, indicating that the three phenotypes analyzed are not developmentally static. Nonetheless, in moderated regression analysis we found no evidence of declining twin similarity for any of the three outcomes in either zygosity group. Moreover, biometric analysis of the twin data revealed minimal differences in heritability estimates across the age range sampled. While small sample size limits our ability to draw firm conclusions at very advanced ages, these findings call into question the hypothesis that the cumulative impact of life experiences diminishes twin similarity at least through age 80. We hypothesize that twins are able to maintain similarity over extended periods of time because in part they are able to construct similar environments that reinforce that similarity.

  16. Utilizing the resource of twins reared apart: their distribution across nine provinces or cities of China.

    Science.gov (United States)

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

    2015-04-01

    Twins reared apart provide a fascinating experiment to distinguish genetic from environmental influences. However, there is as yet no broad report on distribution of twins reared apart, especially in the Chinese population. In this study, information on 18,295 volunteer twin pairs of all age groups was compiled in nine provinces or cities of China, and questionnaires were used for zygosity determination. It was discovered that twins reared apart from 0 to 10 years of age accounted for 2.2% of all twin interviewees, with the proportion of this 0-10 group separated before 1, 2, and 5 years old, accounting for 65.3%, 76.1%, and 91.3%, respectively. The proportion of twins reared apart is not significantly related to zygosity or gender, but it is related to region and twin age. As the age of twins lowers, the proportion of those reared apart gradually decreases. Twins reared apart will become rarer in the future and therefore should be cherished as a resource.

  17. 3~6岁双生子体型遗传分析%Genetic somatotype of twins aged 3-6 years

    Institute of Scientific and Technical Information of China (English)

    郑玉娜; 李玉玲; 季成叶; 陆舜华; 刘燕; 高广嵩; 傅媛; 栾天抒

    2012-01-01

    Objective To analyze the heritabilities of somatotype components and to examine the genetic and environmental influences on the somatotype among twins aged 3 to 6 years. Methods The components of somatotype were calculated by using Heath-Carter method in 72 twin pairs,including 42 monozygotic(MZ)and 30 like-sex dizygotic(DZ) twin pairs aged 3 to 6 years. Heritabilities of somatotype components were estimated by Holzinger formula. Results The results of somatotype dispersion distance (SDD) and somatotype attitudinal distance (SAD) showed that the somatotype of MZ was more similar than that of DZ. The interpair variance of somatotype components showed no significant difference between MZ and DZ. The intrapair variance of mesomorphic and ectomorphic components was greater in DZ than in MZ, but the correlation coefficient was greater in MZ than in DZ. The estimated heritabilities of endomorphic, mesomorphic , and ectomorphic components were 0. 38,0. 67, and 0. 73, respectively. Conclusion There might be genetic and environmental influence effects on somatotype of children aged 3 to 6 years. The endomorphic component is mainly determined by environmental factors,but mesomorphic and ectomorphic components are mainly affected by genetic ones.%目的 分析3~6岁幼儿体型各因子的遗传度,探讨遗传与环境因素对其体型发育的影响.方法 采用Heath-Carter体型法对72对3~6岁同性别双生子[同卵双生子(MZ)42对,异卵双生子(DZ)30对]的体型进行分析,用Holzinger公式估算体型各因子遗传度.结果 二维空间的体型离散距离(SDD)和三维空间体型位置距离(SAD)显示,MZ的体型较DZ更为接近;体型各因子对间方差在2类双生子间均无明显差异,中因子和外因子的对内方差DZ均明显大于MZ、组内相关系数MZ均明显大于DZ;内、中、外3个因子的遗传度分别为0.38、0.67、0.73.结论 遗传与环境因素对3~6岁幼儿体型发育均有一定影响,内因子主要受环

  18. 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.

  19. 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…

  20. ACARDIAC TWIN

    OpenAIRE

    Vinayachandran; Jyothi,; Bindu; Umadevi

    2014-01-01

    Acardiac twin is a very rare complication occurring in monozygotic twins in which one fetus develops normally (pump twin) and the other (recipient twin) demonstrate cardiac non development and othe r anomalies. This may represent an extreme form of TTTS, also referred to as TRAP sequence. 1,2,

  1. 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.

  2. 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, Anne-Mette Bruun; Harmer, Catherine 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...... and questionnaires assessing mood, personality traits and coping. RESULTS: Unexpectedly, high-risk twins showed reduced fear vigilance and lower recognition of fear and happiness relative to low-risk twins. During face processing in the scanner, high-risk twins displayed distinct negative functional coupling between...

  3. High-precision abundances of Sc, Mn, Cu, and Ba in solar twins. Trends of element ratios with stellar age

    CERN Document Server

    Nissen, P E

    2016-01-01

    A previous study of correlations between element abundance ratios, [X/Fe], and ages of solar twin stars is extended to include Sc, Mn, Cu, and Ba. HARPS spectra with S/N > 600 are used to derive very precise (+/- 0.01 dex) differential abundances, and stellar ages with internal errors less than 1 Gyr are obtained by interpolation in the logg - Teff diagram between isochrones calculated with the Aarhus Stellar Evolution Code. For stars younger than 6 Gyr, [X/Fe] is tightly correlated with stellar age for all elements. For ages between 6 and 9 Gyr, the [X/Fe] - age correlations break down and the stars split up into two groups having respectively high and low [X/Fe] for the odd-Z elements. It is concluded that while stars in the solar neighborhood younger than about 6 Gyr were formed from interstellar gas with a smooth chemical evolution, older stars have originated from regions enriched by supernovae with different neutron excesses. Furthermore, the correlations between abundance ratios and stellar age suggest...

  4. Mitral valve regurgitation in twins

    DEFF Research Database (Denmark)

    Bakkestrøm, Rine; Larsen, Lisbeth Aagaard; Møller, Jacob Eifer

    2016-01-01

    BACKGROUND: Smaller observational studies have suggested familial clustering of mitral regurgitation (MR). Using a large twin cohort, the aims were to assess MR concordance rates and assess mortality in MR twins and unaffected cotwins. METHODS: Through the Danish Twin Registry, twins...... with an International Classification of Diseases, Eighth Revision and Tenth Revision diagnosis code of MR born 1880-1989 were identified and proband-wise concordance rates were calculated. To assess whether having a cotwin with MR affected survival, 10 matched twins without MR (n = 5,575) were selected for each MR twin...... (n = 562), and all-cause mortality rates were assessed. RESULTS: Among the 87,432 twins alive January 1, 1977, or later, 494 (0.57%) MR individuals were identified. Six MR concordant pairs were found, of which 3 were monozygotic. Proband-wise concordance rate when accounting for right censoring...

  5. 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.

  6. 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.

  7. High-precision abundances of Sc, Mn, Cu, and Ba in solar twins. Trends of element ratios with stellar age

    Science.gov (United States)

    Nissen, P. E.

    2016-09-01

    Aims: A previous study of correlations between element abundances and ages of solar twin stars in the solar neighborhood is extended to include Sc, Mn, Cu, and Ba to obtain new information on the nucleosynthetic history of these elements. Methods: HARPS spectra with S/N ≳ 600 are used to derive very precise (σ ~ 0.01 dex) differential abundances of Sc, Mn, Cu, and Ba for 21 solar twins and the Sun. The analysis is based on MARCS model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Stellar ages with internal errors less than 1 Gyr are obtained by interpolation in the log g - Teff diagram between isochrones based on the Aarhus Stellar Evolution Code. Results: For stars younger than 6 Gyr, [Sc/Fe], [Mn/Fe], [Cu/Fe], and [Ba/Fe] are tightly correlated with stellar age, which is also the case for the other elements previously studied; linear relations between [X/Fe] and age have χ^2red ˜ 1, and for most stars the residuals do not depend on elemental condensation temperature. For ages between 6 and 9 Gyr, the [X/Fe] - age correlations break down and the stars split up into two groups having respectively high and low [X/Fe] for the odd-Z elements Na, Al, Sc, and Cu. Conclusions: While stars in the solar neighborhood younger than ~ 6 Gyr were formed from interstellar gas with a smooth chemical evolution, older stars seem to have originated from regions enriched by supernovae with different neutron excesses. Correlations between abundance ratios and stellar age suggest that: (i) Sc is made in Type II supernovae along with the α-capture elements; (ii) the Type II to Ia yield ratio is about the same for Mn and Fe; (iii) Cu is mainly made by the weak s-process in massive stars; (iv) the Ba/Y yield ratio for asymptotic giant branch stars increases with decreasing stellar mass; (v) [Y/Mg] and [Y/Al] can be used as chemical clocks when determining ages of solar metallicity stars. Based on data products from observations made

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

    Science.gov (United States)

    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

  9. 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

  10. Heritability of optic disc diameters: a twin study

    DEFF Research Database (Denmark)

    Drobnjak, Dragana; Taarnhøj, Nina Charlotte; Mitchell, Paul

    2011-01-01

    Purpose: To assess the relative influence of genetic and environmental factors on optic disc size and cup/disc ratio in healthy eyes. Methods: A sample of 55 monozygotic and 50 dizygotic healthy twin pairs aged 20-46, all having the same sex within pairs (47 pairs were male) had optic discs......: 20-45%). For cup/disc ratio, additive genetic and unshared environmental factors explained 66% (95% CI: 48-77%) and 34% (95% CI: 23-52%) of the variations, respectively. Discussion: In this healthy twin sample, we found that three quarters of the variations in vertical optic disc and optic cup...... measured from colour fundus photographs according to the Wisconsin Protocol. Structural equation modelling was used to estimate the relative contribution of genetic and environmental factors to the phenotype. Results: Disc dimensions did not vary significantly by age or sex. After adjusting for age and sex...

  11. Genetic and environmental influences on blood pressure variability: a study in twins.

    Science.gov (United States)

    Xu, Xiaojing; Ding, Xiuhua; Zhang, Xinyan; Su, Shaoyong; Treiber, Frank A; Vlietinck, Robert; Fagard, Robert; Derom, Catherine; Gielen, Marij; Loos, Ruth J F; Snieder, Harold; Wang, Xiaoling

    2013-04-01

    Blood pressure variability (BPV) and its reduction in response to antihypertensive treatment are predictors of clinical outcomes; however, little is known about its heritability. In this study, we examined the relative influence of genetic and environmental sources of variance of BPV and the extent to which it may depend on race or sex in young twins. Twins were enrolled from two studies. One study included 703 white twins (308 pairs and 87 singletons) aged 18-34 years, whereas another study included 242 white twins (108 pairs and 26 singletons) and 188 black twins (79 pairs and 30 singletons) aged 12-30 years. BPV was calculated from 24-h ambulatory blood pressure recording. Twin modeling showed similar results in the separate analysis in both twin studies and in the meta-analysis. Familial aggregation was identified for SBP variability (SBPV) and DBP variability (DBPV) with genetic factors and common environmental factors together accounting for 18-40% and 23-31% of the total variance of SBPV and DBPV, respectively. Unique environmental factors were the largest contributor explaining up to 82-77% of the total variance of SBPV and DBPV. No sex or race difference in BPV variance components was observed. The results remained the same after adjustment for 24-h blood pressure levels. The variance in BPV is predominantly determined by unique environment in youth and young adults, although familial aggregation due to additive genetic and/or common environment influences was also identified explaining about 25% of the variance in BPV.

  12. Genetic and environmental factors in associations between infant growth and adult cardiometabolic risk profile in twins.

    Science.gov (United States)

    Touwslager, Robbert N H; Gielen, Marij; Mulder, Antonius L M; Gerver, Willem J M; Zimmermann, Luc J; Dagnelie, Pieter C; Houben, Alfons J H M; Stehouwer, Coen D A; Derom, Catherine; Vlietinck, Robert; Loos, Ruth J F; Zeegers, Maurice P

    2013-10-01

    Accelerated infant growth is associated with an altered, mostly adverse adult cardiometabolic risk profile. The importance of genetic and environmental factors to these associations is unclear. The objective was to examine the importance of genetic and environmental factors in the associations between infant growth and adult cardiometabolic risk factors (anthropometric characteristics, lipids, insulin sensitivity, leptin, blood pressure, and fibrinogen) in twins. Cardiometabolic risk factors were assessed in 240 twin pairs (aged 18-34 y) from the East Flanders Prospective Twin Survey. Infant growth was defined as change in weight z score. We regressed intrapair differences in growth during 4 growth windows (0-1, 1-6, 6-12, and 12-24 mo) against intrapair differences in the risk factors in monozygotic and dizygotic twins separately. Within monozygotic twin pairs only, associations between infant growth and most adult lipids, glucose, leptin, and blood pressure (eg, systolic blood pressure: b = 5.95 mm Hg per change in z score, P = 0.01 in monozygotic twins; b = -1.64, P = 0.82 in dizygotic twins from 12 to 24 mo) were found. Within dizygotic twin pairs only, associations between growth and triglycerides and fibrinogen (eg, fibrinogen: b = 0.07 ln mg/dL per change in z score, P = 0.31 in monozygotic twins; b = 0.79, P = 0.01 in dizygotic twins from 0 to 1 mo) were identified. Most associations showed a detrimental effect of accelerated growth, but beneficial associations were also identified (eg, total-to-high-density-lipoprotein cholesterol ratio: b = -0.22 per change in z score from 1 to 6 mo, P = 0.008 in monozygotic twins). Our data showed that environmental factors play a role in the associations between infant growth and most adult lipids, glucose, leptin, and blood pressure, whereas genetic factors are involved regarding triglycerides and fibrinogen.

  13. Role of genetic and environmental factors in British twins with inflammatory bowel disease.

    Science.gov (United States)

    Ng, Siew C; Woodrow, Susannah; Patel, Nisha; Subhani, Javaid; Harbord, Marcus

    2012-04-01

    Twin studies provide insight into the complex interaction between genetic and environmental factors in the development of inflammatory bowel disease (IBD). We assessed associations between childhood environmental factors and development of Crohn's disease (CD) and ulcerative colitis (UC) in twins. Questionnaires on clinical demographics and exposure to environmental factors were sent to twins with IBD, their healthy co-twins, and their doctors. Kappa statistics were used to examine agreement between twin pairs and odds ratios were calculated by conditional logistic regression. In all, 250 IBD twin pairs (122 CD; 125 UC; 3 CD/UC; 28 concordant pairs) were analyzed. Concordant monozygotic twins with CD showed good agreement for disease location (κ 0.88; 95% confidence interval [CI]: 0.45-1.00), disease behavior (κ 1.00; 95% CI: 0.43-1.00), and moderate agreement for age at diagnosis and need for medical and surgical therapy. Concordant monozygotic twins with UC showed good agreement for disease extent (κ 0.60; CI 0.13-1.00) and use of thiopurines (κ 0.73; CI 0.10-1.00). In discordant twins, symptomatic childhood mumps infection (odds ratio [OR], 3.8; 95% CI, 1.2-11.3) and oral contraceptives (OR, 4.0; 1.1-14.2) were associated with CD. Smoking was associated with CD (OR, 4.3; 95% CI, 1.9-9.8) but inversely associated with UC (OR, 0.3; 95% CI, 0.1-0.9). Both CD and UC twins had suffered more "gastroenteritis" and spent more time with animals than their co-twins. Disease phenotype in CD and disease extent in UC appeared to be genetically influenced. Smoking is a risk factor for CD but is protective for UC. Early exposure to "infections" during childhood may be associated with the development of IBD. Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.

  14. Craniofacial anomalies in twins.

    Science.gov (United States)

    Keusch, C F; Mulliken, J B; Kaplan, L C

    1991-01-01

    Studies of twins provide insight into the relative contribution of genetic and environmental factors in the causality of structural anomalies. Thirty-five affected twin pairs were identified from a group of 1114 patients with congenital craniofacial deformities evaluated from 1972 to 1989. Forty-three of these 70 twins exhibited one or more craniofacial anomalies; these were analyzed for dysmorphic characteristics, zygosity, concordance, and family history. The anomalies were categorized into two groups: malformations and deformations. The malformations (n = 36) included hemifacial microsomia (n = 10), cleft lip and palate (n = 8), cleft palate (n = 4), rare facial cleft (n = 2), craniosynostosis (n = 2), Binder syndrome (n = 2), Treacher Collins syndrome (n = 2), craniopagus (n = 2), CHARGE association (n = 1), frontonasal dysplasia (n = 2), and constricted ears (n = 1). The deformations (n = 7) included plagiocephaly (n = 5), hemifacial hypoplasia (n = 1), and micrognathia (n = 1). Twenty-one monozygotic and 14 dizygotic twin pairs were identified. The concordance rate was 33 percent for monozygotic twins and 7 percent for dizygotic twins.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Methylomic analysis of monozygotic twins discordant for childhood psychotic symptoms

    Science.gov (United States)

    Fisher, Helen L; Murphy, Therese M; Arseneault, Louise; Caspi, Avshalom; Moffitt, Terrie E; Viana, Joana; Hannon, Eilis; Pidsley, Ruth; Burrage, Joe; Dempster, Emma L; Wong, Chloe C Y; Pariante, Carmine M; Mill, Jonathan

    2015-01-01

    Childhood psychotic symptoms are associated with increased rates of schizophrenia, other psychiatric disorders, and suicide attempts in adulthood; thus, elucidating early risk indicators is crucial to target prevention efforts. There is considerable discordance for psychotic symptoms between monozygotic twins, indicating that child-specific non-genetic factors must be involved. Epigenetic processes may constitute one of these factors and have not yet been investigated in relation to childhood psychotic symptoms. Therefore, this study explored whether differences in DNA methylation at age 10 were associated with monozygotic twin discordance for psychotic symptoms at age 12. The Environmental Risk (E-Risk) Longitudinal Twin Study cohort of 2,232 children (1,116 twin pairs) was assessed for age-12 psychotic symptoms and 24 monozygotic twin pairs discordant for symptoms were identified for methylomic comparison. Children provided buccal samples at ages 5 and 10. DNA was bisulfite modified and DNA methylation was quantified using the Infinium HumanMethylation450 array. Differentially methylated positions (DMPs) associated with psychotic symptoms were subsequently tested in post-mortem prefrontal cortex tissue from adult schizophrenia patients and age-matched controls. Site-specific DNA methylation differences were observed at age 10 between monozygotic twins discordant for age-12 psychotic symptoms. Similar DMPs were not found at age 5. The top-ranked psychosis-associated DMP (cg23933044), located in the promoter of the C5ORF42 gene, was also hypomethylated in post-mortem prefrontal cortex brain tissue from schizophrenia patients compared to unaffected controls. These data tentatively suggest that epigenetic variation in peripheral tissue is associated with childhood psychotic symptoms and may indicate susceptibility to schizophrenia and other mental health problems. PMID:26479702

  16. Lung cancer, genetic predisposition and smoking: the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob v. B.; Korhonen, Tellervo; Holst, Klaus;

    2016-01-01

    Background: We aimed to disentangle genetic and environmental causes in lung cancer while considering smoking status. Methods: Four Nordic twin cohorts (43 512 monozygotic (MZ) and 71 895 same sex dizygotic (DZ) twin individuals) had smoking data before cancer diagnosis. We used time...... for lung cancer, nearly all were current smokers at baseline and only one concordant pair was seen among never smokers. Among ever smokers, the case-wise concordance of lung cancer, that is the risk before a certain age conditional on lung cancer in the co-twin before that age, was significantly increased...... pairs. Among smoking discordant pairs, the pairwise HR for lung cancer of the ever smoker twin compared to the never smoker co-twin was 5.4 (95% CI 2.1 to 14.0) in MZ pairs and 5.0 (95% CI 3.2 to 7.9) in DZ pairs. Conclusions: The contribution of familial effects appears to decrease by age...

  17. Lung cancer, genetic predisposition and smoking: the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob v. B.; Korhonen, Tellervo; Holst, Klaus

    2016-01-01

    Background: We aimed to disentangle genetic and environmental causes in lung cancer while considering smoking status. Methods: Four Nordic twin cohorts (43 512 monozygotic (MZ) and 71 895 same sex dizygotic (DZ) twin individuals) had smoking data before cancer diagnosis. We used time...... for lung cancer, nearly all were current smokers at baseline and only one concordant pair was seen among never smokers. Among ever smokers, the case-wise concordance of lung cancer, that is the risk before a certain age conditional on lung cancer in the co-twin before that age, was significantly increased...... pairs. Among smoking discordant pairs, the pairwise HR for lung cancer of the ever smoker twin compared to the never smoker co-twin was 5.4 (95% CI 2.1 to 14.0) in MZ pairs and 5.0 (95% CI 3.2 to 7.9) in DZ pairs. Conclusions: The contribution of familial effects appears to decrease by age...

  18. Genetics study on behavior problems in school-age twins%学龄儿童行为遗传双生子研究

    Institute of Scientific and Technical Information of China (English)

    李玉玲; 季成叶; 关宏岩; 陆舜华; 赵曼; 栾天抒

    2012-01-01

    Objective To estimate the heritability of behavior problems in school-age children by twins data. Methods The behavior problems were assessed in a total of 166 twin pairs aged 6-12 years in Huhhot with the Child Behavior Checklist ( CBCL). Structural equation modeling was performed to evaluate the heritability of behavior problems in school-age children. Results For behavior problems of school-age children, the genetic factors ( heritability) explained about 30. 26% in boys and 32.80% in girls of the total variance. The heritabilities of anxiety/depression, withdrawn, thought problems, attention problems, social problems, delinquent problems, aggressive behavior and other problems were 46. 79% , 56. 45% , 58. 59% , 79. 14% , 26.13% , 37.09% , 84.57% and 75.21% in the boys and 74.99% , 78.33% , 63.25% , 40.11% , 52.09% , 0.00% , 50.51% and 70. 29% in the girls respectively. The gender effect existed in the heritabilities of attention problems and aggressive behavior, and the males heritabilities of them were higher than those of females. The genetic and environmental effects of the behavior problems of school-age children were not influenced by the age. Conclusion The behavior problems of school-age children are influenced by genetic and environmental factors. There are gender effects on the heritabilities of attention problems and aggressive behavior.%目的 利用双生子人群估计学龄儿童行为指标的遗传度,为降低儿童行为问题的发生提供依据.方法 采用Achenbach's儿童行为量表对在呼和浩特市募集的166对6~12岁双生子心理行为问题进行调查.对调查结果进行结构方程模型拟合,估算学龄儿童行为指标的遗传度.结果 行为总粗分遗传度为男30.26%,女32.80%;各行为分因子遗传度分别为焦虑/抑郁(男46.79%,女74.99%)、退缩(男56.45%,女78.33%)、思维(男58.95%,女63.25%)、注意力(男79.14%,女40.11%)、社会化问题(男26.13%,女52.09

  19. 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

    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 46,418 ind...

  20. 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.

  1. Twin births

    DEFF Research Database (Denmark)

    Hoffmann, Elise; Oldenburg, Anna; Rode, Line;

    2012-01-01

    To assess morbidity and mortality in twin pregnancy deliveries, according to chorionicity and mode of delivery.......To assess morbidity and mortality in twin pregnancy deliveries, according to chorionicity and mode of delivery....

  2. A Factorial Analysis of Timed and Untimed Measures of Mathematics and Reading Abilities in School Aged Twins

    Science.gov (United States)

    Hart, Sara A.; Petrill, Stephen A.; Thompson, Lee A.

    2010-01-01

    The present study examined the phenotypic and genetic relationship between fluency and non-fluency-based measures of reading and mathematics performance. Participants were drawn from the Western Reserve Reading and Math Project, an ongoing longitudinal twin project of same-sex MZ and DZ twins from Ohio. The present analyses are based on…

  3. 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.

  4. 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.

  5. A Twin Study of Perthes Disease

    DEFF Research Database (Denmark)

    Metcalfe, David; Van Dijck, Stephanie; Parsons, Nicolas

    2016-01-01

    and genetic associations with LCPD. METHODS: We extracted all twin pairs from the Danish Twin Registry (DTR) in which at least 1 individual had LCPD. The DTR captures every twin pair born alive in Denmark, and those with LCPD were identified by using health record linkage. Probanwise concordance.......00-0.18) for the dizygotic, and 0.18 (95% CI: 0.00-0.40) for the UZ twin pairs. CONCLUSIONS: This study found evidence of familial clustering in LCPD but did not show a genetic component. The absolute risk that a co-twin of an affected individual will develop LCPD is low, even in the case of monozygotic twin pairs.......BACKGROUND: Legg-Calvé-Perthes disease (LCPD) is an idiopathic avascular necrosis of the femoral head. Its etiology is poorly understood, although previous studies have implicated low birth weight and possible genetic determinants. The aim of this study was to identify potential birth weight...

  6. 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; Spector, Tim D; Snieder, Harold

    2012-01-01

    UNLABELLED: 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

  7. 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 thi

  8. Genetic influence on the age at onset of asthma: a twin study

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; Duffy, David Lorenzo; Kyvik, Kirsten Ohm

    2010-01-01

    Although the genetics of asthma susceptibility have been frequently explored, little is known about genetic factors that influence the age at onset of asthma.......Although the genetics of asthma susceptibility have been frequently explored, little is known about genetic factors that influence the age at onset of asthma....

  9. Epigenome-wide association study on identical twins discordant for birth weight

    DEFF Research Database (Denmark)

    Tan, Qihua; Nielsen, Morten Frost Munk; Christiansen, Lene

    induces persistent epigenetic modification detectable at adult ages, we performed a genome-wide DNA methylation profiling in peripheral blood of 150 pairs of identical Danish twins discordant for birth weight using the Illumina Infinium HumanMethylation450 BeadChip featuring 485,000 CpG sites across...... the genome. After quality control and data preprocessing using free R package minfi, data were analysed by a mixed effects model including fixed effect variables such as birth weight difference, age and sex of twin pairs; random effect variables such as batch, well, and sample position on the array, etc....... Statistical analysis revealed 12 probes with p valuetwins is not associated...

  10. 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.

    2015-01-01

    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 clini

  11. Multivariate genetic analysis of atopy phenotypes in a selected sample of twins

    DEFF Research Database (Denmark)

    Thomsen, SF; Ulrik, Charlotte Suppli; Kyvik, KO

    2006-01-01

    , airway hyper-responsiveness (AHR), and positive skin prick test (posSPT) in a sample of adult twins. METHODS: Within a sampling frame of 21,162 twin subjects, 20-49 years of age, from the Danish Twin Registry, a total of 575 subjects (256 intact pairs and 63 single twins), who either themselves and....../or their co-twins reported a history of asthma at a nationwide questionnaire survey, were clinically examined. Symptoms of wheeze and rhinitis were obtained by interview; airway responsiveness and skin test reactivity were measured using standard techniques. Correlations in liability between the different...... traits were estimated and latent factor models of genetic and environmental effects were fitted to the observed data using maximum likelihood methods. RESULTS: The various phenotypic correlations between wheeze, rhinitis, AHR and posSPT were all significant and ranged between 0.50 and 0.86. Traits...

  12. Somatosensory Brain Function and Gray Matter Regional Volumes Differ According to Exercise History: Evidence from Monozygotic Twins.

    Science.gov (United States)

    Hautasaari, Pekka; Savić, Andrej M; Loberg, Otto; Niskanen, Eini; Kaprio, Jaakko; Kujala, Urho M; Tarkka, Ina M

    2017-01-01

    Associations between long-term physical activity and cortical function and brain structure are poorly known. Our aim was to assess whether brain functional and/or structural modulation associated with long-term physical activity is detectable using a discordant monozygotic male twin pair design. Nine monozygotic male twin pairs were carefully selected for an intrapair difference in their leisure-time physical activity of at least three years duration (mean age 34 ± 1 years). We registered somatosensory mismatch response (SMMR) in EEG to electrical stimulation of fingers and whole brain MR images. We obtained exercise history and measured physical fitness and body composition. Equivalent electrical dipole sources of SMMR as well as gray matter (GM) voxel counts in regions of interest indicated by source analysis were evaluated. SMMR dipolar source strengths differed between active and inactive twins within twin pairs in postcentral gyrus, medial frontal gyrus and superior temporal gyrus and in anterior cingulate (AC) GM voxel counts differed similarly. Compared to active twins, their inactive twin brothers showed greater dipole strengths in short periods of the deviant-elicited SMMR and larger AC GM voxel counts. Stronger activation in early unattended cortical processing of the deviant sensory signals in inactive co-twins may imply less effective gating of somatosensory information in inactive twins compared to their active brothers. Present findings indicate that already in 30's long-term physical activity pattern is linked with specific brain indices, both in functional and structural domains.

  13. Effects of asthma on stability of Wisconsin card sorting test measures A twin study

    Institute of Scientific and Technical Information of China (English)

    Yixiao Fu; Huaqing Meng; Hengshu Zhang; Lu Jia; Qinghua Luo

    2008-01-01

    BACKGROUND:The four measures used to assess the stability of the Wisconsin card sorting test (WEST),that is,the number of preservative errors,percentage of preservative errors,number of categories completed,and the number of trials to complete the first category,reflect the function of the frontal lobe.OBJECTIVE:This study was designed to investigate the effects of asthma on the stability of WCST measurements through the use of a twin study,and to analyze whether egg-type difference exists.DESIGN:A cohort study.SETTING:Mental Health Center,the First Affiliated Hospital of Chongqing Medical University.PARTICIPANTS:Fifty-nine pairs of twins,aged 6-16 years,were primarily selected from schools between August 2005 and February 2007 and the WeST and Zygosity identification test was applied.Twins with achromatopsia,severe upper limb diseases,somatic diseases,or mental disorders were excluded.According to disease history of asthmatic attack,children were assigned into asthma(n=16)and non-asthma(n=43)groups.METHODS:Four WCST measurements were determined in the 59 pairs of twins,and egg-type differences were identified in conjunction.RESULTS:All 59 pairs of twins were included in the final analysis.Among the pairs of twins,28 (48.5%)were monozygotic twins,and 31(52%)were dizygotic twins.Among the monozygotic and dizygotic twins,the number of preservative errors and percentage of preservative errors were significantly higher in the asthma group than in the non-asthma group(P0.05).CONCLUSION:Asthma may affect the stability of WCST measures,but egg-type differences do not exist.

  14. A twin study of weight loss and metabolic efficiency.

    Science.gov (United States)

    Hainer, V; Stunkard, A; Kunesová, M; Parízková, J; Stich, V; Allison, D B

    2001-04-01

    To assess the genetic contribution to determinants of therapeutic weight loss in obese female identical twins. Subjects were studied for 40 days on an inpatient unit in three phases: 7 baseline days; 28 days of weight reduction by a very low calorie diet (1.6 MJ per day); and 5 days after weight reduction. Fourteen pairs of premenopausal obese female identical twins (age: 39.0+/-1.7 y; body weight (BW): 93.9+/-21.2 kg; body mass index (BMI): 34.2+/-7.8 kg/m2). : Body composition by hydrodensitometry and resting metabolic rate by indirect calorimetry were assessed before and after weight loss. : There was great variability among pairs in loss of weight (5.9-12.4 kg) and body fat (3.1-12.4 kg). By contrast, the intraclass correlation (ICC) within twin pairs was 0.85, P<0.001 for weight and 0.88, P<0.001 for body fat. A measure of metabolic efficiency, calculated as the difference between 'estimated' and 'measured' energy deficit showed high intrapair correlation (ICC=0.77; P<0.001). The high correlation in metabolic efficiency within twin pairs in response to therapeutic weight loss suggests a strong genetic contribution.

  15. 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

  16. 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, T.; Plassman, B.L.; Tanner, C.M.; Dick, D. M.; Rinehart, S.A.; Nichols, W.C.

    2005-01-01

    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 aging 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 there were 578 twin-pairs with DNA analyzed. 96.8% (519/536) had confirmation of zygosity assignment via questionnaire. Among 42 pairs whose questionnaire responses were inconclusive for assigning zygosity, 50% were found to be monozygous and 50% were dizygous. There was some evidence for greater misclassification of presumed DZ pairs in the healthy aging 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. PMID:16176721

  17. Urticaria in Monozygotic and Dizygotic Twins

    Directory of Open Access Journals (Sweden)

    Simon Francis Thomsen

    2012-01-01

    Full Text Available 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 (1.36–2.72, P=0.000; and atopic dermatitis, HR=1.44 (1.02–2.06, P=0.041 were significant risk factors for urticaria. After adjustment for sex and age at onset of urticaria in the index twin, the risk of urticaria was increased in MZ cotwins relative to DZ cotwins, HR=1.42 (0.63–3.18, P=0.394. Genetic factors explained 45% (16–74%, P=0.005, of the variation in susceptibility to urticaria. The genetic correlation between urticaria and hay fever was 0.45 (0.01–0.89, P=0.040. Conclusions. Susceptibility to urticaria is partly determined by genetic factors. Urticaria is more common in women, and in subjects with hay fever and atopic dermatitis, and shares genetic variance with hay fever.

  18. Twin-to-twin delivery time: neonatal outcome of the second twin.

    Science.gov (United States)

    Schneuber, Susanne; Magnet, Eva; Haas, Josef; Giuliani, Albrecht; Freidl, Thomas; Lang, Uwe; Bjelic-Radisic, Vesna

    2011-12-01

    To examine the effect of twin-to-twin delivery time (TTDT) on neonatal outcome. We evaluated twin deliveries >34 weeks of gestation. Twin pregnancies with both twins delivered by cesarean section and pregnancies with antenatal complications were excluded. We analyzed TTDT and neonatal outcomes of the second twin (umbilical arterial pH value (pH(art)), Apgar scores at 1, 5 and 10 minutes, need for intensive care). The study population was divided into two homogenous groups based on the mode of delivery: (A) vertex presentation and vaginal delivery of both twins, (B) vertex presentation and vaginal or vaginal operative delivery of twin I, breech or transverse presentation and vaginal breech delivery or cesarean section (CS) of twin II. A total of 207 twin pairs were included in our study. In Group A (n = 151) there were no significant correlations between TTDT and pH(art) or Apgar scores at 1,5 and 10 minutes of twin II (p = .156; 0.861; 0.151 and 0.384, respectively). In Group B (n = 56), the mean pH(art) of twin II was inversely correlated to TTDT, but not significantly (p = .417). TTDT was inversely related to 1-min and 5-min Apgar scores, but not significantly (p = .330; p = .138, respectively). The 10-min Apgar score showed no correlation with TTDT (p = .638). Increasing TTDT was not associated with adverse fetal outcome. Expectant management of the second twin appears possible and elapsed time alone does not appear to be an indication for intervention.

  19. Analysis of clinical efficacy of interceptive treatment of Class II division 2 malocclusion in a pair of twins through the use of two modified removable appliances

    Science.gov (United States)

    CONDÒ, R.; PERUGIA, C.; BARTOLINO, M.; DOCIMO, R.

    2011-01-01

    SUMMARY The interceptive therapeutic approach of a functional type is indicated for the treatment of Class II Division 2 mandibular retrusion with deep bite, where improvement is required not only in occlusal relationships but also in skeletal and aesthetic parameters. Purpose The aim of this study is to assess, in two identical twins suffering from the same malocclusion, the effectiveness and clinical stability of functional interceptive Class II division 2 treatment during puberty by mandibular retro-positioning associated with deep bite, and to compare skeletal changes and dental and dental-alveolar changes induced by the application of two different modified removable appliances: Clark’s Twin block and Bergersen’s Occlus-o-guide. Results The results show that both devices allowed for circumvention of the pre-functional therapy phase aimed at correcting the upper labial segment, and for the conversion of the Class II division 1 incisor relationship, they were able to promote significant and obvious clinical effects. Conclusions The study shows that Class II Division 2 functional type interceptive treatment of mandibular retrusion with deep bite conducted in the puberal phase through clinical use of modified Bergersen’s Occlus-o-guide® allowed for simultaneous resolution of the skeletal, dental-alveolar and dental problems in one step, while that using modified Clark’s Twin-block still requires a second phase of treatment necessary to resolve the alignment, levelling, inter-cuspidation of the arches, optimization of the dental overjet and overbite parameters and to the stabilization of the basal Class I. PMID:23285386

  20. Twins Early Development Study (TEDS): a genetically sensitive investigation of cognitive and behavioral development from childhood to young adulthood.

    Science.gov (United States)

    Haworth, Claire M A; Davis, Oliver S P; Plomin, Robert

    2013-02-01

    The Twins Early Development Study (TEDS) is a large longitudinal sample of twins born in England and Wales between 1994 and 1996. The focus of TEDS has been on cognitive and behavioral development, including difficulties in the context of normal development. TEDS began when multiple births were identified from birth records and the families were invited to take part in the study; 16,810 pairs of twins were originally enrolled in TEDS. More than 10,000 of these twin pairs remain enrolled in the study to date. DNA has been collected for more than 7,000 pairs, and genome-wide genotyping data for two million DNA markers are available for 3,500 individuals. The TEDS families have taken part in studies when the twins were aged 2, 3, 4, 7, 8, 9, 10, 12, 14, and 16 years of age. Data collection is currently underway to assess the adult destinations of the twins as they move from school to university and the workplace. Between January 2012 and December 2014, all of the TEDS twins will turn 18, and the study will transition to an adult sample. TEDS represents an outstanding resource for investigating the developmental effects of genes and environments on complex quantitative traits from childhood to young adulthood and beyond.

  1. Heritability assessment of cartilage metabolism. A twin study on circulating procollagen IIA N-terminal propeptide (PIIANP)

    DEFF Research Database (Denmark)

    Munk, H L; Svendsen, A J; Hjelmborg, J V B;

    2014-01-01

    OBJECTIVE: The aim of this investigation was to estimate the heritability of circulating collagen IIA N-terminal propeptide (PIIANP) by studying mono- and dizygotic healthy twin pairs at different age and both genders. DESIGN: 598 monozygotic (MZ) and dizygotic (DZ) twin individuals aged 18......-59 years were recruited from the Danish Twin Registry. PIIANP was measured by competitive ELISA. The similarity of circulating PIIANP among MZ and DZ twins was assessed by intraclass correlations according to traits. The heritability was estimated by variance component analysis accounting for additive...... and dominant genetic factors as well as shared and non-shared environment but ignoring epistasis (genetic inter-locus interaction) and gene-environment interaction. RESULTS: The intraclass correlation of PIIANP in MZ and DZ twins was 0.69 (0.60-0.76) and 0.46 (0.34-0.58) respectively indicating a significant...

  2. '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.

  3. Hypoadiponectinemia in extremely low gestational age newborns with severe hyperglycemia--a matched-paired analysis.

    Directory of Open Access Journals (Sweden)

    Andre Oberthuer

    Full Text Available BACKGROUND: Hyperglycemia is commonly observed in extremely low gestational age newborns (ELGANs and is associated with both increased morbidity and mortality. The objective of this study was to examine the relationship between neonatal hyperglycemia and adiponectin levels in ELGANs. METHODOLOGY/PRINCIPAL FINDINGS: Ten preterm infants between 22+6/7 and 27+3/7 weeks' gestation with neonatal hyperglycemia (defined as pre-feeding blood glucose levels above 200mg/dl on two consecutive measurements with a maximum parenteral glucose infusion of 4 mg/kg*min(-1 formed the case cohort of this study. To every single patient of this case cohort a patient with normal fasting ( = pre-feeding blood glucose levels was matched in terms of gestational age and gender. Adiponectin ELISAs were performed both at onset of hyperglycemia and at term-equivalent age. In the case cohort 9/10 patients had to be treated with insulin for 1-26 days (range 0.01-0.4 IU/kg*h(-1. Compared to matched-paired controls, significant hypoadiponectinemia was observed at onset of hyperglycemia in these affected patients (6.9 µg/ml versus 15.1 µg/ml, p = 0.009. At term equivalent age, normoglycemia without any insulin treatment was found in both groups. Moreover, adiponectin levels at that time were no longer significantly different (12.3 µg/ml versus 20.0 µg/ml; p = 0.051 possibly indicating a mechanistic relevance of this adipokine in regulating insulin sensitivity in ELGANs. CONCLUSIONS/SIGNIFICANCE: Decreased circulating adiponectin levels are correlated with hyperglycemia in ELGANs and may contribute to the pathogenesis of impaired glucose homeostasis in these infants. These findings suggest that adiponectin might be a potential future drug target for the potentially save treatment of hyperglycemia in pre-term infants.

  4. 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

  5. Estimating twin concordance for bivariate competing risks twin data

    DEFF Research Database (Denmark)

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

    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 experienced...... 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...... 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...

  6. The similiarity of facial expressions in response to emotion-inducing films in reared-apart twins.

    Science.gov (United States)

    Kendler, K S; Halberstadt, L J; Butera, F; Myers, J; Bouchard, T; Ekman, P

    2008-10-01

    While the role of genetic factors in self-report measures of emotion has been frequently studied, we know little about the degree to which genetic factors influence emotional facial expressions. Twenty-eight pairs of monozygotic (MZ) and dizygotic (DZ) twins from the Minnesota Study of Twins Reared Apart were shown three emotion-inducing films and their facial responses recorded. These recordings were blindly scored by trained raters. Ranked correlations between twins were calculated controlling for age and sex. Twin pairs were significantly correlated for facial expressions of general positive emotions, happiness, surprise and anger, but not for general negative emotions, sadness, or disgust or average emotional intensity. MZ pairs (n=18) were more correlated than DZ pairs (n=10) for most but not all emotional expressions. Since these twin pairs had minimal contact with each other prior to testing, these results support significant genetic effects on the facial display of at least some human emotions in response to standardized stimuli. The small sample size resulted in estimated twin correlations with very wide confidence intervals.

  7. Update on the NAS-NRC Twin Registry.

    Science.gov (United States)

    Page, William F

    2006-12-01

    The National Academy of Sciences-National Research Council (NAS-NRC) Twin Registry is one of the oldest, national population-based twin registries in the United States. It consists of 15,924 white male twin pairs born in the years 1917 to 1927 (inclusive), both of whom served in the armed forces, mostly during World War II. This article updates activity in this registry since the earlier 2002 article in Twin Research. The results of clinically based studies on dementia, Parkinson's disease, age-related macular degeneration, and primary osteoarthritis were published, as well as articles based on previously collected questionnaire data on chronic fatigue syndrome, functional limitations, and healthy aging. In addition, risk factor studies are being planned to merge clinical data with earlier collected risk factor data from questionnaires. Examination data from the subset of National Heart, Lung, and Blood Institute (NHLBI) twins resulted in a number of articles, including the relationship of endogenous sex hormones to coronary heart disease and morphological changes in aging brain structures. The NEO Five-Factor Personality Inventory (a paper-and-pencil self-administered questionnaire) has been fielded for the first time. A push to consolidate the various data holdings of the registry is being made.

  8. Perinatal mortality among twins and singletons in a city in southeastern Brazil, 1984-1996

    Directory of Open Access Journals (Sweden)

    Beiguelman Bernardo

    2000-01-01

    Full Text Available Analysis of 116,699 deliveries (1062 twin pairs and 115,637 singletons which occurred from 1984 to 1996 at the largest obstetric center in Campinas, SP, Brazil, provided the following conclusions: 1 despite the low percentage of twin births (0.9%, 10.7% of all early neonatal deaths and 3.5% of all stillbirths were twins. Compared to singletons, the likelihood of stillbirths and early neonatal deaths among twins was 1.9 and 6.5 times greater, respectively. 2 The proportion of twins among early neonatal deaths tended to decrease, probably because of improvements in prenatal and perinatal care. 3 The critical period for early neonatal deaths in singletons and twins lasted for the three first days after birth. 4 The incidence of perinatal deaths among twins was highest among MM pairs, followed by FF pairs, and lowest among MF pairs. 5 There was a trend towards a decrease in the annual rate of early neonatal deaths among both singletons and twins, and of stillbirths among singletons, the latter being more conspicuous among females. 6 The sex ratio of singletons was practically stable among living newborns, but showed strong cyclic variation among early neonatal deaths, and a tendency to increase among stillbirths. Twins who died in the first week, as well as living twins showed a strong increase in their sex ratio from 1984 to 1996. 7 The mean gestational age of singletons was highest among living newborns followed by stillbirths, and was lowest among early neonatal deaths. The mean gestational age of living twins was higher than that of early neonatal deaths, but not different from that of stillbirths. 8 The mean birth weight of singletons and twins was highest among living newborns, followed by stillbirths, and lowest among early neonatal deaths. 9 Apgar scores > or = 7 obtained five minutes after birth are inadequate as a reliable indicator of the clinical condition of the newborn, since almost half of the early neonatal deaths had 5-min Apgar

  9. 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.

  10. Twins' injuries: genetic and environmental risks / twin research reports / human interest stories.

    Science.gov (United States)

    Segal, Nancy L

    2011-04-01

    The relative contributions of genetic and environmental factors to unintentional injuries are of interest to families with young twins. A recent study found that childhood injuries are explained mostly by child-specific environmental factors. Next, twin research reviews of the association between periodontal disease and cancer, secular trends in gestational age and birthweight, and language development in hearing and deaf co-twins are also summarized. Interesting reports of newborn twins, twin-like relationships, twin interactions and missed twin relationships are presented.

  11. 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.

  12. Association between subjective memory complaints and depressive symptoms after adjustment for genetic and family environmental factors in a Japanese twin study.

    Science.gov (United States)

    Tanaka, Haruka; Ogata, Soshiro; Omura, Kayoko; Honda, Chika; Kamide, Kei; Hayakawa, Kazuo

    2016-03-01

    The aim of this study was to investigate the association between subjective memory complaints (SMCs) and depressive symptoms, with and without adjustment for genetic and family environmental factors. We conducted a cross-sectional study using twins and measured SMCs and depressive symptoms as outcomes and explanatory variables, respectively. First, we performed regression analyses using generalized estimating equations to investigate the associations between SMCs and depressive symptoms without adjustment for genetic and family environmental factors (individual-level analyses). We then performed regression analyses for within-pair differences using monozygotic (MZ) and dizygotic (DZ) twin pairs and MZ twin pairs to investigate these associations with adjustment for genetic and family environmental factors by subtracting the values of one twin from those of co-twin variables (within-pair level analyses). Therefore, differences between the associations at individual- and within-pair level analyses suggested confounding by genetic factors. We included 556 twins aged ≥ 20 years. In the individual-level analyses, SMCs were significantly associated with depressive symptoms in both males and females [standardized coefficients: males, 0.23 (95% CI 0.08-0.38); females, 0.35 (95% CI 0.23-0.46)]. In the within-pair level analyses using MZ and same-sex DZ twin pairs, SMCs were significantly associated with depressive symptoms. In the within-pair level analyses using the MZ twin pairs, SMCs were significantly associated with depressive symptoms [standardized coefficients: males, 0.32 (95% CI 0.08-0.56); females, 0.24 (95% CI 0.13-0.42)]. This study suggested that SMCs were significantly associated with depressive symptoms after adjustment for genetic and family environmental factors.

  13. 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...

  14. Genetic and Environmental Influences on Traits of Gender Identity Disorder: A Study of Japanese Twins Across Developmental Stages.

    Science.gov (United States)

    Sasaki, Shoko; Ozaki, Koken; Yamagata, Shinji; Takahashi, Yusuke; Shikishima, Chizuru; Kornacki, Tamara; Nonaka, Koichi; Ando, Juko

    2016-10-01

    The present study examined: (1) gender and age differences of mean gender identity disorder (GID) trait scores in Japanese twins; (2) the validity of the prenatal hormone transfer theory, which predicts that, in dizygotic (DZ) twin pairs, twins with an opposite-gender co-twin more frequently exhibit GID traits than twins with a same-gender co-twin; and (3) the magnitude of genetic and environmental influences on GID traits as a function of age and gender. Data from 1450 male twin pairs, 1882 female twin pairs, and 1022 DZ male-female pairs ranging from 3 to 26 years of age were analyzed. To quantify individual variances in GID traits, each participant completed four questionnaire items based on criteria for GID from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Our most important findings were: (1) Japanese females exhibited GID traits more frequently than males and Japanese children exhibited GID traits less frequently than adolescents and adults (among females, the prevalence was 1.6 % in children, 10 % in adolescents, and 12 % in adults; among males, the prevalence was 0.5, 2, and 3 %, respectively); (2) the data did not support the prenatal hormone transfer theory for GID traits; and (3) a large part of the variance for GID traits in children was accounted for by familial factors; however, the magnitude was found to be greater in children than in adolescents or adults, particularly among females. This study suggests that although the prevalence is likely to increase, familial effects are likely to decrease as individuals age.

  15. 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

    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......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...... 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...

  16. 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....

  17. [The Chinese national twin cohort: an update].

    Science.gov (United States)

    Gao, W J; Li, L M

    2017-06-10

    The importance of large cohort studies in China has been increasingly emphasized. As special group in the population, twins provide excellent natural resources since they share the same birthday, maternal intrauterine environment and early family environment. Twin cohorts are unique for and benefit on controlling the confounding factors as age, gender (same-sex twins), genetic background (monozygotic twins) or early environment (being raised together) in the etiological studies on complex diseases. In this review, we briefly introduce the objectives, current situation, challenges and opportunities related to the Chinese national twin cohort, focusing on the characteristics of twins that are different from other groups in the general population.

  18. 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.

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

    Science.gov (United States)

    Li, Shuxia; Kyvik, Kirsten Ohm; Pang, Zengchang; Zhang, Dongfeng; Duan, Haiping; Tan, Qihua; Hjelmborg, Jacob; Kruse, Torben; Dalgård, Christine

    2016-01-01

    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, cultural, social-economic backgrounds and geographical environments. The study covered a relatively large sample of 502 pairs of Danish adult twins followed up for a long period of 12 years with a mean age at intake of 38 years (range: 18-65) and a total of 181 Chinese adult twin 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. 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 for long-term change in most of the phenotypes in Danish twins except for triglycerides and hip circumference. Compared with Danish twins, the Chinese twins tended to have higher genetic control over the longitudinal changes in lipids (except high density lipoprotein cholesterol) and glucose, higher unique environmental contribution to blood pressure but no genetic contribution to longitudinal change in body mass traits. Our results emphasize the major contribution of unique environment to the observed intra-individual variation in all metabolic phenotypes in both samples, and meanwhile reveal differential patterns of genetic and common environmental regulation on changes over time in metabolic phenotypes across the two samples.

  20. 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

  1. A Study of Sedentary Behaviour in the Older Finnish Twin Cohort: A Cross Sectional Analysis

    Directory of Open Access Journals (Sweden)

    Maarit Piirtola

    2014-01-01

    Full Text Available The aim of the study was to investigate the effects of age, sex, and body mass index (BMI on total sitting time among the Finnish twin cohort. Also, heritability and environmental factors were analysed. The final sample included 6713 twin individuals 53–67 years of age (46% men. Among them there were 1940 complete twin pairs (732 monozygotic [MZ] and 1208 dizygotic [DZ] twin pairs. Sedentary behaviour was queried with a self-reported questionnaire with multiple-choice questions about sitting time at different domains. The mean total sitting time per day was 6 hours 41 minutes (standard deviation: 2 hours 41 minutes. The total sitting time was less in women than in men (P=0.002. Older age was associated with less total sitting time (P<0.001. Those with higher body mass index had higher total sitting time in age and sex adjusted analysis (P<0.001. MZ pairs were more similar for sitting time than DZ pairs, with initial estimates of heritability for the total sitting time of 35%.The influence of shared environmental factors was negligible (1%, while most (64% of the variation could be ascribed to unique environmental factors, the latter including measurement error.

  2. Twin study of genetic and environmental influences on adult body size, shape, and composition

    DEFF Research Database (Denmark)

    Schousboe, K; Visscher, P M; Erbas, B;

    2004-01-01

    OBJECTIVE: To investigate the genetic and environmental influences on adult body size, shape, and composition in women and men, and to assess the impact of age. MATERIALS AND METHODS: In this cross-sectional study of 325 female and 299 male like-sex healthy twin pairs, on average 38 y old (18-67 ...

  3. Exploring the Co-Development of Reading Fluency and Reading Comprehension: A Twin Study

    Science.gov (United States)

    Little, Callie W.; Hart, Sara A.; Quinn, Jamie M.; Tucker-Drob, Elliot M.; Taylor, Jeanette; Schatschneider, Christopher

    2017-01-01

    This study explores the co-development of two related but separate reading skills, reading fluency and reading comprehension, across Grades 1-4. A bivariate biometric dual change score model was applied to longitudinal data collected from 1,784 twin pairs between the ages of 6 and 10 years. Grade 1 skills were influenced by highly overlapping…

  4. 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…

  5. 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…

  6. Change of genetic determinants of left ventricular structure in adolescence : Longitudinal evidence from the Georgia Cardiovascular Twin Study

    NARCIS (Netherlands)

    Kapuku, Gaston K.; Ge, Dongliang; Vemulapalli, Sarita; Harshfield, Gregory A.; Treiber, Frank A.; Snieder, Harold

    2008-01-01

    BACKGROUND Genetic contribution to left ventricular (LV) structure is generally recognized, but whether and how this influence varies by ethnicity or with age is unknown. METHODS Participants were 517 European-American (EA) and African-American (AA) twin pairs (mean age: 14.6 +/- 3.0) at visit 1 and

  7. Genetics study on circumference in preschool-age twins%学龄前双生子儿童围度指标的遗传学研究

    Institute of Scientific and Technical Information of China (English)

    栾天抒; 李玉玲; 陆舜华; 刘燕; 郑玉娜; 赵曼

    2012-01-01

    [Objective! To assess the genetic and environmental influences on body circumference of preschool-age children,and the effect of sex and age. [Methods] A total of 101 twin pairs aged 3~6 years old were measured.including 42 monozygotic (MZ),30 like-sex and 29 opposite-sex dizygotic (DZ). The circumference items included head circumference, chest circumference, waist circumference, hip circumference, arm circumference and calf circumference. The structural equation modeling was used to evaluate the heritability of each circumference item. [Results] Except head circumference 's fitting model was AES,others were ACES,which indicated that the circumference items were influenced by genetic,environmental factors and age effects. After adjusting age, the heritabilities of head circumference, chest circumference, waist circumference,hip circumference,arm circumference and calf circumference were 0. 83,0. 56,0. 77,0. 49,0. 58,0. 82 in boys, and 0. 75,0. 43,0. 72,0. 63,0. 36,0. 76 in girls respectively. [Conclusion] The circumference of head, waist and calf of preschool-age children are mainly influenced by genetic factors, the circumferences of chest, hip and arm are mainly influenced on environmental ones.%[目的]分析遗传和环境因素对学龄前双生子儿童围度发育的影响及其性别和年龄因素的作用. [方法]对3~6岁101对双生子(同卵双生子42对、同性别异卵双生子30对,异性别异卵双生子29对)的头围、胸围、腰围、臀围、上臂围及小腿围进行测量;对测量结果进行结构方程模型拟合,并估算各指标遗传度. [结果]最佳模型除头围为AES外,其他各指标均为ACES模型,遗传、环境、年龄因素对各指标均有不同程度影响.校正年龄后,各指标遗传度为:头围(男0.83,女0.75)、胸围(男0.56,女0.43)、腰围(男0.77,女0.72)、臀围(男0.49,女0.63)、上臂围(男0.58,女0.36)、小腿围(男0.82,女0.76). [结论]学龄前儿童头围、腰围、小腿围

  8. 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....

  9. The Charles Perkins Centre's Twins Research Node.

    Science.gov (United States)

    Ferreira, Lucas C; Craig, Jeffrey M; Hopper, John L; Carrick, Susan E

    2016-08-01

    Twins can help researchers disentangle the roles of genes from those of the environment on human traits, health, and diseases. To realize this potential, the Australian Twin Registry (ATR), University of Melbourne, and the Charles Perkins Centre (CPC), University of Sydney, established a collaboration to form the Twins Research Node, a highly interconnected research facility dedicated specifically to research involving twins. This collaboration aims to foster the adoption of twin designs as important tools for research in a range of health-related domains. The CPC hosted their Twins Research Node's launch seminar entitled 'Double the power of your research with twin studies', in which experienced twin researchers described how twin studies are supporting scientific discoveries and careers. The launch also featured twin pairs who have actively participated in research through the ATR. Researchers at the CPC were surveyed before the event to gauge their level of understanding and interest in utilizing twin research. This article describes the new Twins Research Node, discusses the survey's main results and reports on the launch seminar.

  10. 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...... was significantly associated with survival, even after adjustment for chronological age, sex, and rearing environment. Perceived age was still significantly associated with survival after further adjustment for physical and cognitive functioning. The likelihood that the older looking twin of the pair died first...... age, controlled for chronological age and sex, also correlated significantly with physical and cognitive functioning as well as with leucocyte telomere length. CONCLUSION: Perceived age-which is widely used by clinicians as a general indication of a patient's health-is a robust biomarker of ageing...

  11. 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...... in both twins and polyhydramnios as the cause of imminent preterm labour. After initiation of haemodialysis treatment, ultrasound evaluation showed a significant decrease in amniotic fluids, and also reduction in blood urea nitrogen and in clinical complaints could be observed. At a gestational age of 28...... weeks + 4 days, delivery was performed by Caesarean section. This case study shows that effective treatment of elevated uraemic toxins significantly reduced the morbidity risks of the twins....

  12. Situs Inversus Totalis in Twins: A Brief Review and a Life History / Twin Research: Twin Studies of Trisomy 21; Monozygotic Twin Concordance for Bilateral Coronoid Hyperplasia; Prenatal Hormonal Effects in Mixed-Sex Non-Human Primate Litters; Insurance Mandates and Twinning After In Vitro Fertilization / News Reports: First Report of Identical Twin Puppies; Twins Sisters Turn 100; Remembering an Identical Twin Production Designer; New York City Marathon Quadruplets.

    Science.gov (United States)

    Segal, Nancy L

    2017-02-01

    The presence of situs inversus totalis (full reversal of internal organs) in twins is briefly reviewed. Information gathered from 35-year-old monozygotic (MZ) female twin pair discordant for this condition is presented. This is followed by summaries of research on the frequency of trisomy 21 (Down syndrome) in twins, the first case of MZ twin concordance for bilateral coronoid hyperplasia, prenatal hormonal effects in mixed-sex non-human primate litters, and links between insurance mandates and twinning following in vitro fertilization. The final section of this article describes twin-related events reported in the news, namely, the first recorded birth of identical twin puppies; the 100th birthday celebration of a pair of fraternal female twins, the passing of an award-winning identical twin production designer, and the first running of the New York City Marathon by a set of quadruplets.

  13. Hypertensive disorders in twin pregnancy

    OpenAIRE

    Santema, Job; Koppelaar, Elin; 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 the antenatal clinic and booked before a gestational age of 24 weeks was matched for maternal age, parity, and gestational age at delivery with a singleton pregnancy delivered in the same year. Prima...

  14. Intrapair Comparison of Life-Course Appetite and Physical Activity in Elderly Danish Twins: Reliability and Association With Subsequent Survival

    Science.gov (United States)

    Løkkegaard, Laura E.; Larsen, Lisbeth A.; Christensen, Kaare

    2016-01-01

    Avoiding overeating and being physically active is associated with healthy aging, but methodological issues challenge the quantification of the association. Intrapair comparison of twins is a study design that attempts to minimize social norm-driven biased self-reporting of lifestyle factors. We aimed to investigate the association between self-reported lifestyle factors and subsequent survival in 347 Danish twin pairs aged 70 years and older and, additionally, to investigate the reliability of these self-reports. The twins were interviewed in 2003 and followed for mortality until 2015. They were asked to compare their appetite and physical activity to that of their co-twins in different stages of life. On an individual level, we found a positive association between current self-reported physical activity and late-life survival for elderly twins. This was supported by the intrapair analyses, which revealed a positive association between midlife and current physical activity and late-life survival. A positive association between lower appetite and late-life survival was found generally over the life course in the individual level analyses but not in the intrapair analyses. Kappa values for the inter-twin agreement on who ate the most were 0.16 to 0.34 in different life stages, and for physical activity 0.19 to 0.26, corresponding to a slight-to-fair agreement. Approximately, 50% of the twin pairs were not in agreement regarding physical activity, and of these twins 75% (95% CI: 67–82%) considered themselves the most active twin. These findings indicate a still-existing tendency of answering according to social norms, even in a twin study designed to minimize this. PMID:27485765

  15. Specific cognitive abilities in 5- to 12-year-old twins.

    Science.gov (United States)

    Foch, T T; Plomin, R

    1980-11-01

    Eleven tests of specific cognitive abilities were administered to 108 pairs of young twins (average age of 7.6 years). Internal consistencies are high for all measures except Raven's Coloured Progressive Matrices and Delayed Picture Memory. Two-month, test-retest reliabilities are also reported. The twin sample is representative in terms of both means and variances when compared to normative data from standardization samples, and twin correlations for height and weight are similar to those obtained in six other twin studies. Because all measures were highly correlated with age (average correlation with age was 0.64), scores were aged adjusted. Previous twin studies of specific cognitive abilities in adolescents and adults found genetic variance for nearly all tests. In contrast, our study of young twins yielded significant genetic influence for only 1 of the 11 measures, PIAT Reading Recognition, and suggested the possibility of genetic influence on 2 others (vocabulary and WISC-R mazes). Environmental influences seem to dominate, particularly for nonverbal measures, as children begin their education. In accord with other studies, we found that between-family environmental factors have an important influence on the development of nearly all of the measures of specific cognitive abilities. However, we found that our tests of perceptual speed and memory were substantially influenced by within-family environmental factors independent of error.

  16. Effect of birth parameters on retinal vascular caliber: the Twins Eye Study in Tasmania.

    Science.gov (United States)

    Sun, Cong; Ponsonby, Anne-Louise; Wong, Tien Y; Brown, Shayne A; Kearns, Lisa S; Cochrane, Jenny; MacKinnon, Jane R; Ruddle, Jonathan B; Hewitt, Alex W; Liew, Gerald; Dwyer, Terence; Scurrah, Katrina; Mackey, David A

    2009-03-01

    Recent studies reported an association between smaller birth size and narrower retinal vascular caliber, but it remains unclear whether this association is attributed to confounding by shared environment or genetic factors. At a mean age of 9.3 years, 266 twins (49 monozygotic and 84 dizygotic pairs) in the Twins Eye Study in Tasmania underwent an ophthalmic examination including retinal photography. Retinal vascular caliber was measured using a validated protocol. The majority of these twins were also in the Tasmanian Infant Health Study, which prospectively collected data on birth parameters and antenatal maternal factors. We conducted the main analysis using linear mixed models, accounting for birth set clustering. Both the within-pair (-9.73; 95% CI: -14.68 to -4.77 microm per 5-cm decrease in birth length) and between-pair associations (-7.15; 95% CI: -11.54 to -3.01) with retinal arteriolar caliber were significant and of similar magnitude (difference in effect, P=0.61), after adjusting for age, sex, maternal smoking, mean arterial blood pressure, and other confounders. These associations remained within dizygotic and monozygotic pairs. Analyses of head circumference and retinal arteriolar caliber were similar to those of birth length (within-pair regression coefficient: -2.41; 95% CI: -5.09 to 0.28; between-pair regression coefficient: -2.60; 95% CI: -5.00 to -0.19). For birth weight, only a between-pair association was evident (-7.28; 95% CI: -13.07 to -1.48). This study demonstrates a consistent association between smaller birth size and narrower retinal arterioles in twins. The independent effect of shorter birth length on retinal arteriolar caliber supports a role for twin-specific supply line factors affecting fetal growth on vascular structure.

  17. 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.

  18. Twinning across the Developing World.

    Directory of Open Access Journals (Sweden)

    Jeroen Smits

    Full Text Available BACKGROUND: Until now, little was known about the variation in incidence of twin births across developing countries, because national representative data was lacking. This study provides the first comprehensive overview of national twinning rates across the developing world on the basis of reliable survey data. METHODS: Data on incidence of twinning was extracted from birth histories of women aged 15-49 interviewed in 150 Demographic and Health Surveys, held between 1987 and 2010 in 75 low and middle income countries. During the interview, information on all live births experienced by the women was recorded, including whether it was a singleton or multiple birth. Information was available for 2.47 million births experienced by 1.38 million women in a period of ten years before the interview. Twinning incidence was measured as the number of twin births per thousand births. Data for China were computed on the basis of published figures from the 1990 census. Both natural and age-standardized twinning rates are presented. RESULTS/CONCLUSIONS: The very low natural twinning rates of 6-9 per thousand births previously observed in some East Asian countries turn out to be the dominant pattern in the whole South and South-East Asian region. Very high twinning rates of above 18 per thousand are not restricted to Nigeria (until now seen as the world's twinning champion but found in most Central-African countries. Twinning rates in Latin America turn out to be as low as those in Asia. Changes over time are small and not in a specific direction. SIGNIFICANCE: We provide the most complete and comparable overview of twinning rates across the developing world currently possible.

  19. Combined genome scans for body stature in 6,602 European twins

    DEFF Research Database (Denmark)

    Perola, Markus; Sammalisto, Sampo; Hiekkalinna, Tero

    2007-01-01

    Twin cohorts provide a unique advantage for investigations of the role of genetics and environment in the etiology of variation in common complex traits by reducing the variance due to environment, age, and cohort differences. The GenomEUtwin (http://www.genomeutwin.org) consortium consists...... of eight twin cohorts (Australian, Danish, Dutch, Finnish, Italian, Norwegian, Swedish, and United Kingdom) with the total resource of hundreds of thousands of twin pairs. We performed quantitative trait locus (QTL) analysis of one of the most heritable human complex traits, adult stature (body height......) using genome-wide scans performed for 3,817 families (8,450 individuals) derived from twin cohorts from Australia, Denmark, Finland, Netherlands, Sweden, and United Kingdom with an approximate ten-centimorgan microsatellite marker map. The marker maps for different studies differed and they were...

  20. 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: Twe

  1. A Danish Twin Study of Schizophrenia Liability

    DEFF Research Database (Denmark)

    Kläning, Ulla; Trumbetta, Susan L; Gottesman, Irving I

    2016-01-01

    We studied schizophrenia liability in a Danish population-based sample of 44 twin pairs (13 MZ, 31 DZ, SS plus OS) in order to replicate previous twin study findings using contemporary diagnostic criteria, to examine genetic liability shared between schizophrenia and other disorders, and to explo...

  2. 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.

  3. The effect of chorionicity and twin-to-twin delivery time interval on short-term outcome of the second twin

    DEFF Research Database (Denmark)

    Hjortø, Sofie; Nickelsen, Carsten; Petersen, Janne;

    2013-01-01

    Abstract Objectives: To investigate the effect of chorionicity and twin-to-twin delivery time interval on short-term outcome in the second twin. Additionally, to investigate predictors of adverse outcome in both twins. Methods: Data included vaginally delivered twins (≥ 36 weeks) from Copenhagen...... University Hospitals (2001-09). The association between delivery interval and adverse outcome parameters were compared for monochorionic (MC) and dichorionic (DC) twins by multiple linear regression. Predictors were studied by logistic regression. Results: There were 554 twin pairs: 57 MC and 485 DC. We...... found no difference in the decrease of pH (p = 0.912) and Apgar (p = 0.609) in relation to increasing time interval. Neonatal unit (NICU) admissions did not differ (p = 0.167). Apgar ≤ 7 (p twin, whereas first (p = 0.001) or second (p twin Apgar...

  4. The Texas Twin Project.

    Science.gov (United States)

    Harden, K Paige; Tucker-Drob, Elliot M; Tackett, Jennifer L

    2013-02-01

    Socioeconomic position, racial/ethnic minority status, and other characteristics of the macro-environment may be important moderators of genetic influence on a wide array of psychosocial outcomes. Designed to maximize representation of low socioeconomic status families and racial/ethnic minorities, the Texas Twin Project is an ongoing study of school-age twins (preschool through 12th grade) enrolled in public schools in the Austin, Texas and Houston, Texas metropolitan areas. School rosters are used to identify twin families from a target population with sizable populations of African American (18%), Hispanic/Latino (48%), and non-Hispanic White (27%) children and adolescents, over half of whom meet US guidelines for classification as economically disadvantaged. Initial efforts have focused on a large-scale, family-based survey study involving both parent and child reports of personality, psychopathology, physical health, academic interests, parent-child relationships, and aspects of the home environment. In addition, the Texas Twin Project is the basis for an in-laboratory study of adolescent decision-making, delinquency, and substance use. Future directions include geographic expansion of the sample to the entire state of Texas (with a population of over 25 million) and genotyping of participating twins.

  5. 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.

  6. Vascular programming in twins: the effects of chorionicity and fetal therapy for twin-to-twin transfusion syndrome.

    Science.gov (United States)

    Gardiner, H M; Barlas, A; Matsui, H; Diemert, A; Taylor, M J O; Preece, J; Gordon, F; Greenwald, S E; Hecher, K

    2012-06-01

    We assessed vascular programming in genetically identical monochorionic twin pairs with twin-to-twin transfusion syndrome (TTTS) treated differently in utero by serial amnioreduction or fetal laser arterial photocoagulation. This case-control study re-assessed four twin groups at median 11 years comprising 20 pairs of monochorionic diamniotic twins: nine treated by amnioreduction (TTTS-amnio) and eleven by laser (TTTS-laser) with seven monochorionic and six dichorionic control pairs. Outcome measures were current blood pressure (BP), brachio-radial arterial stiffness derived from pulse wave velocity (PWV), resting microcirculation (Flux) and response to heating and post-occlusive reactive hyperaemia measured using laser Doppler. Potential confounders [PWV and BP at first study, current height, weight, heart rate and twin type (ex-recipient, ex-donor or heavier/lighter of pair)] were accounted for by Mixed Linear Models statistical methodology. PWV dichorionic > monochorionic (P = 0.024); systolic and diastolic BP dichorionic > TTTS-amnio and TTTS-laser (P = 0.004, P = 0.02 and P = 0.005, P = 0.02, respectively). Within-twin pair pattern of PWV discordance was similar in laser treated and dichorionic controls (heavier-born > lighter), opposite to TTTS-amnio and monochorionic controls. Flux monochorionic > dichorionic (P = 0.044) and heavier > lighter-born (P = 0.024). TTTS-laser and dichorionic diamniotic showed greatest hyperaemic responses (dichorionic > TTTS-amnio or monochorionic controls (P = 0.007, P = 0.025). Hyperaemic responses were slower in heavier-born twins (P = 0.005). In summary, monochorionic twins had lower BP, arterial stiffness and increased resting vasodilatation than dichorionic twins implying shared fetal circulation affects vascular development. Vascular responses in laser-TTTS were similar to dichorionic and opposite to TTTS-amnio suggesting a lasting effect of fetal therapy on vascular health.

  7. Idiopathic intracranial hypertension in female homozygous twins.

    OpenAIRE

    Fujiwara, S; Sawamura, Y; Kato, T.; Abe, H.; Katusima, H

    1997-01-01

    The authors report on female homozygous twins with idiopathic intracranial hypertension. At the age of 12 years, both twins simultaneously developed visual disturbances with photophobia. At the age of 19 years, an ophthalmological examination disclosed papilloedema in both their eyes. At the age of 22 years, a lumbar puncture showed raised CSF pressure over (200 mm H2O) in both twins. Their neurological and radiological examinations were extremely similar; both of them had severely impaired v...

  8. The Southern Illinois Twins and Siblings Study (SITSS): description and update.

    Science.gov (United States)

    Dilalla, Lisabeth Fisher; Gheyara, Sufna; Bersted, Kyle

    2013-02-01

    This update on the Southern Illinois Twins and Siblings Study (SITSS) documents some of the follow-up studies that have been conducted and results that have been obtained from this sample. At the current time, 283 twin pairs, 8 triplet families, 98 non-twin sibling pairs, and 287 singletons have been enrolled in SITSS. Twins and triplets are tested as young as 1 year of age and then every year on their birthday through age 5 years. A variety of follow-up studies have been conducted for SITSS children through age 20. Results thus far have demonstrated significant genetic influences on social behaviors such as aggression, victimization, and attention toward facial expressions. Interesting interactions have been documented between the dopamine receptor D4 gene (DRD4) and the social environment (parental sensitivity or peer aggression) as they predict children's aggressive behaviors. In addition, increased difficulty with social interactions has been noted for twins versus singletons. Thus, this multi-trait, multi-method behavior genetic data set contributes to our understanding of the etiology of social behaviors in preschoolers and to predictors of similar behaviors through adolescence.

  9. Say No to Fake Twin Brothers

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China vows to fight fake products that exploit a home appliance stimulus project in rural areas Haier Co. Ltd., China’s top home appliance manufacturer, is well known for its logo depicting a pair of twin

  10. Role of deformation twins in static recrystallization kinetics of high-purity alpha titanium

    Science.gov (United States)

    Won, Jong Woo; Lee, Taekyung; Hong, Seong-Gu; Lee, Yongmoon; Lee, Jeong Hun; Lee, Chong Soo

    2016-11-01

    The importance of deformation twins in static recrystallization kinetics of high-purity alpha titanium was investigated by carrying out thermal annealing tests of deformed materials in combination with electron-backscatterdiffraction- based microstructural analysis. Prior to thermal annealing, the material was compressed to a true strain of 0.22 along three directions to introduce different twinning characteristics. Our results showed that deformation twins substantially promoted the static recrystallization process by deepening the microstructural inhomogeneity induced by the formation of twin boundaries and twinning-induced crystallographic lattice reorientation. Twin morphology was also observed to be important because it influenced the extent of microstructural inhomogeneity. Intersecting twin morphology, caused by the activation of multiple twin variants, was more effective than parallel twin morphology, caused by the activation of a single twin variant (or a twin variant pair), because it gave rise to more twin boundaries, more twin boundary junctions (intersections, triple junctions, etc.), and greater in-grain crystallographic orientation spread.

  11. Pregnancy prognosis associated with an isolated single umbilical artery in twin pregnancy.

    Science.gov (United States)

    Cade, Thomas J; Da Silva Costa, Fabricio; Reidy, Karen; Doyle, Lex W; Mitchell, Sarah E; Palma-Dias, Ricardo; Umstad, Mark P

    2014-12-01

    To determine the prognosis of an isolated single umbilical artery (SUA) in a twin pregnancy, we selected twin pregnancies with a second trimester ultrasound diagnosing a SUA in at least one fetus at our tertiary hospital. This was confirmed by placental histopathology or by expert review of ultrasound images. Cases were identified by searching the hospital ultrasound database over a period of 7.5 years. Higher order multiples or coexistent aneuploidy or major anomalies were excluded. Each case of an isolated SUA was assigned three consecutive twin pregnancy controls paired for chorionicity and maternal age. Primary outcomes were preterm birth <34 weeks, small for gestational age (SGA) or perinatal death. Other outcomes included antenatal growth restriction, mode of delivery, and admission to neonatal intensive care or special care nursery. Nine pregnancies (18 fetuses) were identified for analysis as cases. Isolated SUA was associated with preterm birth <34 weeks (odds ratio = 12.2; 95% CI = 2.0-75.2; p = .005) but not for SGA. There was also no difference in SGA between the affected twin and its normal co-twin. Perinatal death was increased but after controlling for gestational age and clustering this finding was no longer significant. We conclude that isolated SUA in twins adds a degree of risk to an already high-risk pregnancy but does not increase the need for surveillance for growth restriction.

  12. 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.

    2014-01-01

    Purpose: 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. Method: A population-based sample of 473 twin pairs participated. Multilevel modeling estimated means and variances of vocabulary and…

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

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; 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......,680 monozygotic and 30,054 dizygotic same sex male twin pairs. We incorporated time-to-event analyses to estimate the risk concordance and heritability while accounting for censoring and competing risks of death, essential sources of biases that have not been accounted for in previous twin studies modeling cancer...... 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...

  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. Feature Discretization for Individuality Representation in Twins Handwritten Identification

    Directory of Open Access Journals (Sweden)

    Bayan O. Mohammed

    2011-01-01

    Full Text Available Problem statement: The study on twins is an important form of study in the forensic and biometrics field as twins share similar genetic traits. Handwriting is one of the common types of forensic evidence. Differentiating the similarities of writing of a pair of twins is critical in establishing the reliability of handwriting identification. Writing style can be used as biometric features in authenticating individual uniqueness where these unique features can be used to identify the writer, including between a pair of twins. Existing works in Writer Identification concentrate on feature extraction and the classification task in order to identify authorship. The high similarity in a pair of twins’ handwriting may degrade classification performance. There should be some standards to represent these unique features before entering into the classification task which is with the use of discretization technique. Approach: We proposed a new framework for writer identification in terms of identifying twins' handwriting and showed the effect of discretization process on handwriting samples of a pair of twins in order to obtain individual identification. Results: An experiment has been done at the Sulaimania University in Iraq with fourteen pairs of identical twins where each twin provides 4 samples of handwriting for the purpose of data collecting. These samples were implemented in this research making a comparison between the new proposed framework and classic framework. Conclusion: Our experimental results showed that with new framework identification of handwriting of a pair of twins can be improved through the discretization process.

  16. Twin Baryogenesis

    CERN Document Server

    Farina, Marco; Shin, Chang Sub

    2016-01-01

    In the context of Twin Higgs models, we study a simple mechanism that simultaneously generates asymmetries in the dark and visible sector through the out-of-equilibrium decay of a TeV scale particle charged under a combination of baryon and twin baryon number. We predict the dark matter to be a 5 GeV twin baryon, which is easy to achieve because of the similarity between the two confinement scales. Dark matter is metastable and can decay to three quarks, yielding indirect detection signatures. The mechanism requires the introduction of a new colored particle, typically within the reach of the LHC, of which we study the rich collider phenomenology, including prompt and displaced dijets, multi-jets, monojets and monotops.

  17. Forensic medical evaluation age-related changes aorta and pair large arteries

    Directory of Open Access Journals (Sweden)

    Efimov А.А.

    2015-06-01

    Full Text Available Objective: differentiation of age-dependence indices of aorta, carotid, brachial, femoral arteries and drawing the mathematical model for forensic age determinations on their basis. Material and methods. Objects were: aorta, fragments of right and left carotid, brachial and femoral arteries taken in a complex of 186 male and female corpses, died at the age of 17-94. Research methods consisted of organometrical, histological, micrometrical, correlative and regressive analysis. The Results. Correlative and regressive analysis of 35 indicators of aorta, carotid, brachial and femoral arteries was conducted. All material was divided into figures with a significant correlation with age and performance of age-independent. The mathematical model was composed for calculation of age. Conclusion. Indicated involution of arterial wall and compiled on the basis of a mathematical model for determination the age could be taken as the basis for forensic method of age determination.

  18. Twin-Arginine Protein Translocation

    NARCIS (Netherlands)

    Goosens, Vivianne J; van Dijl, Jan Maarten

    2016-01-01

    Twin-arginine protein translocation systems (Tat) translocate fully folded and co-factor-containing proteins across biological membranes. In this review, we focus on the Tat pathway of Gram-positive bacteria. The minimal Tat pathway is composed of two components, namely a TatA and TatC pair, which a

  19. The effect of chorionicity and twin-to-twin delivery time interval on short-term outcome of the second twin.

    Science.gov (United States)

    Hjortø, Sofie; Nickelsen, Carsten; Petersen, Janne; Secher, Niels Jørgen

    2014-01-01

    To investigate the effect of chorionicity and twin-to-twin delivery time interval on short-term outcome in the second twin as well as to investigate the predictors of adverse outcome in both twins. Data included vaginally delivered twins (≥36 weeks) from Copenhagen University Hospitals (2001-2009). The association between delivery interval and adverse outcome parameters was compared for monochorionic (MC) and dichorionic (DC) twins by multiple linear regression. Predictors were studied by logistic regression. There were 554 twin pairs, of which 57 were MC and 485 DC. We found no difference in the decrease of pH (p = 0.912) and Apgar (p = 0.609) in relation to increasing time interval. Neonatal unit (NICU) admissions did not differ (p = 0.167). Apgar ≤7 (p < 0.001) and pH ≤ 7.20 (p = 0.002) increased first twin risk of NICU admission, whereas first (p = 0.001) or second (p < 0.001) twin Apgar ≤7 and second twin pH ≤7.00 (p = 0.003) increased second twin risk of NICU admission. Increasing delivery interval was associated with a significant decrease in pH and Apgar, but there was no difference between MC and DC twins. Low Apgar of the first twin increased the risk of second twin NICU admission.

  20. Electron-Pair Production in 158 AGeV/c Pb-Au Collisions from CERES

    CERN Document Server

    Yurevich, Sergey

    2006-01-01

    The CERES experiment is devoted to the measurement of low-mass electron pairs in proton and ion-induced collisions at the Super Proton Synchrotron accelerator. The main goal of the CERES experiment is to investigate modifications of hadron properties in hot and dense nuclear matter. A significant enhancement of dilepton pair yield with respect to expectations based on hadron decays was observed in the mass range 0.25 m 0.7 GeV/c. This fascinating result can only be described by models invoking in-medium modifications of the meson. To distinguish between different theoretical explanations of the enhancement the experiment was upgraded in 1998 by the addition of a radial TPC to improve the mass resolution in the vector meson region. In this thesis, the analysis of the data sample taken in 2000 in 158 A GeV/c Pb-Au collisions with the upgraded experimental setup is presented. The observed enhancement of the pairs confirms previous results of CERES. The data, compared to the theoretical calculations based on drop...

  1. 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....

  2. Determination of Zygosity in Adult Chinese Twins Using the 450K Methylation Array versus Questionnaire Data.

    Directory of Open Access Journals (Sweden)

    Biqi Wang

    Full Text Available Previous studies have shown that both single nucleotide polymorphisms (SNPs and questionnaires-based method can be used for twin zygosity determination, but few validation studies have been conducted using Chinese populations. In the current study, we recruited 192 same sex Chinese adult twin pairs to evaluate the validity of using genetic markers-based method and questionnaire-based method in zygosity determination. We considered the relatedness analysis based on more than 0.6 million SNPs genotyping as the golden standards for zygosity determination. After quality control, qualified twins were left for relatedness analysis based on identical by descent calculation. Then those same sex twin pairs were included in the zygosity questionnaire validation analysis. Logistic regression model was applied to assess the discriminant ability of age, sex and the three questions in zygosity determination. Leave one out cross-validation was used as a measurement of internal validation. The results of zygosity determination based on 65 SNPs in 450k methylation array were all consistent with genotyping. Age, gender, questions of appearance confused by strangers and previously perceived zygosity consisted of the most predictable model with a consistency rate of 0.8698, cross validation predictive error of 0.1347. For twin studies with genotyping and\\or 450k methylation array, there would be no need to conduct other zygosity testing for the sake of costs consideration.

  3. Age related-changes in the neural basis of self-generation in verbal paired associate learning.

    Science.gov (United States)

    Vannest, Jennifer; Maloney, Thomas; Kay, Benjamin; Siegel, Miriam; Allendorfer, Jane B; Banks, Christi; Altaye, Mekibib; Szaflarski, Jerzy P

    2015-01-01

    Verbal information is better retained when it is self-generated rather than when it is received passively. The application of self-generation procedures has been found to improve memory in healthy elderly and in individuals with impaired cognition. Overall, the available studies support the notion that active participation in verbal encoding engages memory mechanisms that supplement those used during passive observation. Thus, the objective of this study was to investigate the age-related changes in the neural mechanisms involved in the encoding of paired-associates using a self-generation method that has been shown to improve memory performance across the lifespan. Subjects were 113 healthy right-handed adults (Edinburgh Handedness Inventory >50; 67 females) ages 18-76, native speakers of English with no history of neurological or psychiatric disorders. Subjects underwent fMRI at 3 T while performing didactic learning ("read") or self-generation learning ("generate") of 30 word pairs per condition. After fMRI, recognition memory for the second word in each pair was evaluated outside of the scanner. On the post-fMRI testing more "generate" words were correctly recognized than "read" words (p adults recognizing the "generated" words less accurately (p age, but the benefit from self-generation remained consistently significant across ages. Independent component analysis of the neuroimaging data revealed an extensive set of components engaged in self-generation learning compared with didactic learning, and identified areas that were associated with age-related changes independent of performance.

  4. Neonatal morbidity in growth-discordant monochorionic twins: comparison between the larger and the smaller twin.

    Science.gov (United States)

    Lopriore, Enrico; Sluimers, Carolien; Pasman, Suzanne A; Middeldorp, Johanna M; Oepkes, Dick; Walther, Frans J

    2012-08-01

    Fetal growth restriction in singletons has been shown to enhance fetal lung maturation and reduce the risk of respiratory distress syndrome due to increased endogenous steroid production. However, data on lung maturation in growth-discordant monochorionic (thus, identical) twins are lacking. Our objective was to compare the risk of severe neonatal morbidity between the larger and the smaller twin in monochorionic twins with birth weight discordance (BWD). We included in the study all consecutive monochorionic diamniotic pregnancies with severe BWD (≥25%) and two live-born twins delivered at our center (n=47 twin pairs). We compared the incidence of neonatal morbidity, particularly respiratory distress syndrome (RDS), and cerebral lesions between the larger and the smaller co-twin. The incidence of severe neonatal morbidity in the larger and smaller twin was 38% (18/47) and 19% (9/47), respectively (odds ratio (OR) 2.66, 95% confidence interval (CI) 0.94-7.44) and was due primarily to the higher incidence of RDS, 32% (15/47) and 6% (3/47), respectively (OR 6.88, 95% CI 1.66-32.83). In conclusion, this study shows that the larger twin in monochorionic twin pairs with BWD is at increased risk of severe neonatal morbidity, particularly RDS, compared to the smaller twin.

  5. Genetic vs Environmental Factors That Correlate With Rosacea: A Cohort-Based Survey of Twins.

    Science.gov (United States)

    Aldrich, Nely; Gerstenblith, Meg; Fu, Pingfu; Tuttle, Marie S; Varma, Priya; Gotow, Erica; Cooper, Kevin D; Mann, Margaret; Popkin, Daniel L

    2015-11-01

    To our knowledge, this is the first study on rosacea to formally define genetic and environmental contributions. To study a cohort of identical and fraternal twins to determine whether genetic factors contribute to rosacea development and, if genetic factors are present, quantitatively estimate the genetic contribution, as well as to identify environmental factors that correlate with rosacea by controlling for genetic susceptibility. Identical and fraternal twins were surveyed regarding risk factors implicated in rosacea. Faculty dermatologists determined a rosacea score for each twin participant according to the National Rosacea Society (NRS) grading system. Data were collected at the annual Twins Days Festival in Twinsburg, Ohio, on August 4-5, 2012, and August 2-3, 2013. Analysis was conducted for several months after each meeting. A cohort of 550 twin individuals, with most from Ohio, Pennsylvania, and the northeastern United States, participated. The NRS score and rosacea subtype were assessed using the NRS grading system and physical examination by board-certified dermatologists. Among the 275 twin pairs (550 individuals), there were 233 identical twin pairs with a mean rosacea score of 2.46 and 42 fraternal twin pairs with a mean rosacea score of 0.75. We observed a higher association of NRS scores between identical vs fraternal twins (r = 0.69 vs r = 0.46; P = .04), demonstrating a genetic contribution. Using the ACE model (proportion of variance in a trait heritable secondary to additive genetics [A] vs the proportions due to a common environment [C] and unique environment [E]), we calculated this genetic contribution to be 46%. A higher NRS score was also significantly associated with the following factors: age (r = 0.38; P twins allows us to separate genetic susceptibility and the influence of environmental factors affecting rosacea. We found that approximately half of the contribution to the NRS score could be accounted for by genetics

  6. 学龄双生子儿童头面部特征的遗传学分析%Genetic Analysis on Craniofacial Characteristics of School-age Twins

    Institute of Scientific and Technical Information of China (English)

    李玉玲; 季成叶; 刘燕; 丁一; 栾天抒; 赵曼; 郑玉娜

    2013-01-01

    为探讨遗传与环境因素对学龄双生子儿童头面部特征的影响,对呼和浩特市和包头市7-12岁369对双生子儿童(同卵180对,同性别异卵141对,异性别异卵48对)的16项头面部指标进行活体测量.采用通径分析方法,用Mx软件拟合最佳结构方程模型,计算各指标遗传与环境方差组分,分析年龄、性别的作用.结果发现,校正年龄后,头部指标中头围的遗传度(男66%,女66%)较高:面部指标中,容貌面高的遗传度(男73%,女84%)最高,其次为鼻宽(男57%,女67%)、眼内角间宽(男57%,女50%)和额最小宽(男50%,女50%);头长(男64%,女25%)、头宽(男26%,女82%)、眼外角间宽(男76%,女34%)和容貌耳长(男23%,女70%)的遗传度存在一定的性别差异.表明遗传因素与环境因素对学龄双生子儿童的头面部发育均有一定影响,其中遗传因素对男女头围及容貌面高、男性头长和眼外角间宽、女性头宽、鼻宽、口宽、容貌耳长的影响相对较大.%The purpose of this paper is to analyze genetic and environmental influences on craniofacial development of 16 anthropometric items of school-age children in China of 369 twin pairs including 180 monozygotic (MZ), 141 like-sex and 48 opposite-sex dizygotic (DZ) aged 7 to 12 years enrolled in schools in Hohhot and Baotou. Anthropometric items were measured using the standard methods of measurement. Quantitative genetic model fitting and estimates of variance components were done with Mx, a structural equation modeling package designed for the analysis of twin and family data. After adjusting for age, the results were as follows. In cephalic measurements, head circumference had a higher heritability (male 66%, female 66%). Higher heritability of facial measurements was physiognomic facial height (male 73%, female 84%), nose breadth (male 57%, female 67%), interocular breadth ( male 57%, female 50%) and minimum frontal breadth (male 50

  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. Cross-sectional association between soda consumption and body mass index in a community-based sample of twins.

    Science.gov (United States)

    Eney, Anna E; Tsang, Siny; Delaney, Joseph A; Turkheimer, Eric; Duncan, Glen E

    2017-08-22

    Consumption of sugar-sweetened beverages, such as soda, have been shown to play an important role in weight gain. Although soda consumption has been associated with body mass index (BMI) in many studies, it has been difficult to ascertain a true causal relationship between soda consumption and BMI for two reasons. First, findings have been based largely on observational and cross-sectional studies, with much less evidence from randomized controlled trials. Second, the reported relationships may be confounded by genetic and shared environmental factors that affect both soda consumption and BMI. In the present study, we used the twin design to better understand the relationship between soda consumption and BMI by accounting for measured and unmeasured confounds in non-experimental data. Associations from genetically informed tests in twins are considered "quasi-causal," suggesting that our confidence in the causal underpinning of the association between soda consumption and BMI has been strengthened. We hypothesized that the association between soda consumption and BMI would be significant both between and within twins. This was a cross sectional study of 5787 same sex adult twin pairs (18-97 years, 66% female) from the community based Washington State Twin Registry. Structural equation modeling (SEM) was employed to investigate associations between soda consumption and BMI in the population (the phenotypic association between exposure and outcome among all twins treated as individuals) and within pairs of identical and fraternal twins (the quasi-causal association controlling for between pair genetic and environmental confounds). Among all twins, there was a significant phenotypic association between soda consumption and BMI that held when controlling for age, sex, race, annual household income, and education level (P consumption on BMI was greatly reduced and no longer significant, with a large genetic confound in both men and women (P consumption was associated

  9. Heritability of refractive astigmatism: a population-based twin study among 63- to 75-year-old female twins.

    Science.gov (United States)

    Pärssinen, Olavi; Kauppinen, Markku; Kaprio, Jaakko; Koskenvuo, Markku; Rantanen, Taina

    2013-09-09

    To examine the heritability of refractive astigmatism in older women. Astigmatism was measured with an autorefractor in 88 monozygotic and 82 dizygotic female twin pairs aged 63 to 75 years. The prevalence and distribution of astigmatism and polar values J0 and J45 were estimated by standard statistical methods. Bivariate maximum likelihood model fitting was used to estimate genetic and environmental variance components using information from both eyes. Mean astigmatism of the more astigmatic eye was 0.93 diopters (D; SD ±0.58). Astigmatism of at least 0.25 D, 0.5 D, 0.75 D, or 1.0 D in either eye was present in 99.7%, 88.5%, 66.5%, and 46.2% of cases, respectively. The main direction of astigmatism was against the rule. The age-adjusted quantitative genetic modeling revealed that additive genetic effects accounted for 33.3% (95% confidence interval [CI], 21.9%-43.8%) of the total variance of astigmatism and for 18% (95% CI, 4%-31%) of the total variance of polar value J45 of both eyes (bivariate model), with the remaining variances due to nongenetic effects. There were no significant correlations between the twin pairs for polar value J0. In elderly female twins, additive genetic effects accounted for one-third of the variance of the amount of astigmatism and only a small fraction of the total variance of polar value J45.

  10. Twin methodology in epigenetic studies.

    Science.gov (United States)

    Tan, Qihua; Christiansen, Lene; von Bornemann Hjelmborg, Jacob; Christensen, Kaare

    2015-01-01

    Since the final decades of the last century, twin studies have made a remarkable contribution to the genetics of human complex traits and diseases. With the recent rapid development in modern biotechnology of high-throughput genetic and genomic analyses, twin modelling is expanding from analysis of diseases to molecular phenotypes in functional genomics especially in epigenetics, a thriving field of research that concerns the environmental regulation of gene expression through DNA methylation, histone modification, microRNA and long non-coding RNA expression, etc. The application of the twin method to molecular phenotypes offers new opportunities to study the genetic (nature) and environmental (nurture) contributions to epigenetic regulation of gene activity during developmental, ageing and disease processes. Besides the classical twin model, the case co-twin design using identical twins discordant for a trait or disease is becoming a popular and powerful design for epigenome-wide association study in linking environmental exposure to differential epigenetic regulation and to disease status while controlling for individual genetic make-up. It can be expected that novel uses of twin methods in epigenetic studies are going to help with efficiently unravelling the genetic and environmental basis of epigenomics in human complex diseases.

  11. 高龄双胎妊娠的围产结局分析%Perinatal outcomes in women aged 35 and over with twin pregnancy

    Institute of Scientific and Technical Information of China (English)

    陈敏玲; 王子莲; 凌家炜; 韩振艳

    2010-01-01

    目的 探讨高龄双胎妊娠的围产结局.方法 回顾性分析我院69例高龄双胎病例,随机对照176例非高龄双胎的临床资料,比较两组在妊娠并发症、妊娠合并症、和胎儿预后等方面的差异.结果 ①高龄组接受辅助生育技术受孕比例显著高于非高龄对照组(P<0.05);②高龄组<32孕周早产发生率明显高于对照组(P<0.05),而其他并发症及合并症两组间未见显著性差异;③高龄组以极低出生体重儿(<1500 g)比例显著高于对照组(P<0.05).高龄组新生儿窒息率及胎儿窘迫发生率明显增高(P<0.05).结论 高龄双胎妊娠不良妊娠结局主要与<32孕周的严重早产、极低体重儿、新生儿窒息及胎儿窘迫密切相关,应针对性加强高龄双胎的围生期监护,警惕严重早产的发生.%Objective The aim of this study is to present perinataloutcomes of twin gestations in older women. Methods We conducted a retrospective cohort study of 69 cases of twin pregnancies maternal age 35 years and older( study group)in our department, compared with 176 twin pregnancies cases of maternal age less than 35 years( control group). Results ①Conceptions after assisted reproductive technology were significantly higher in study group(P<0.05 ). ②The rate of preterm labour lower than 32 gestational weeks was significantly higher in the study group(P<0.05). The other complications rate did not differ singnificantly from the control groups. (3) The very low birth weight ( VLBW < 1,500 g) rate was significantly higher in the study group ( P<0.05 ), the rate of neonatal asphyxia and fetal distress were statistically significant higher in study group (P<0.05). Conclusion Advanced maternal age was related with higher incidence of the severe preterm labour(<32 gestational weeks) ,the very low birth weight(<1,500 g) ,fetal distress,neonatal asphyxia. It is important to close monitoring during perinatal period in women aged 35 and

  12. 双胎妊娠中胎儿性别和分娩孕周的相关性研究%Correlation of the Fetal Sex of Twin Pregnancy and Gestational Age

    Institute of Scientific and Technical Information of China (English)

    季景环; 姚晓玲; 李莉; 杨素琴; 张曼丽

    2011-01-01

    Objective To explore the influence of fetus's sex in twin pregnancy on gestation. Methods Retrospectively analyse the 94 cases of twin pregnancy from our hospital during the period from March 2008 to July 2009, which are divided into three groups by fetus's sex of twin male, twin female, a male and a female fpr comparison and analysis of gestation and premature delivery rate. Result No statistical difference in maternal age and average twin body weight( P > 0.05 ). Twin male fetuses average gestation 256.84 day,premature delivery rate 58.06%; twin female fetus 263.65 day, 16. 13% ;one male one female 260.76 day, 24.24%. The average gestation and premature delivery rate are statistically significantly different between twin male fetuses and twin female fetus( P < 0.05 ), Conclusion fetus's sex will influence gestation and premature delivery rate in twin pregnancy, female fetus is one of the premature delivery factors.%目的 探讨双胎妊娠中胎儿性别对分娩孕周的影响.方法 回顾性分析我院2008年3月至2009年7月住院分娩的94例双胎妊娠产妇资料,按胎儿性别分为双男胎、双女胎、一男一女胎三组,对其孕周及早产率进行比较与分析.结果 三组双胎妊娠产妇年龄和双胎儿平均体质量间差异无统计学意义(P>0.05),孕周和早产例数间差异有统计学意义(P<0.05).双男胎组孕周最短,双女胎组孕周最长.三组双胎妊娠产妇双男胎组早产率最高,双女胎组早产率最低.结论 双胎妊娠中胎儿性别影响妊娠孕周,男胎是导致早产的一个因素.

  13. 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...

  14. 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...... of inheritance of AIS remains unclear. Studies on concordance in twin pairs provide a basis for analysing the influence of genetic versus environmental factors. In 2007, using self-report of AIS from the Danish Twin Registry, concordance rates of 0.13 in monozygotic twins and 0.00 in dizygotic twins were...... 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...

  15. Mate choice and friendship in twins: evidence for genetic similarity.

    Science.gov (United States)

    Rushton, J Philippe; Bons, Trudy Ann

    2005-07-01

    This study examined the genetic and environmental contribution to people's preference for spouses and friends to be similar to themselves. In their responses to 130 personality, attitude, and demographic questions, 174 pairs of monozygotic (MZ) twins resembled each other (r= .53) more than did 148 pairs of dizygotic (DZ) twins (r= .32), 322 pairs of spouses (r= .32), and 563 pairs of best friends (r= .20). It was not previously recognized that spouses and friends are as similar as DZ twins. MZ twins also chose spouses and best friends more similar to their co-twins' friends and spouses than did DZ twins (mean rs = .22 vs. .14). The twins' preference for spouses and friends similar to themselves was about 34% due to the twins' genes, 12% due to the twins' common environment, and 54% due to the twins' unique (nonshared) environment. Similarity to partners was more pronounced on the more heritable items than the less heritable items. It is concluded that people are genetically inclined to choose as social partners those who resemble themselves at a genetic level.

  16. Evidence for higher heritability of somatotype compared to body mass index in female twins.

    Science.gov (United States)

    Reis, Victor Machado; Machado, João V; Fortes, Marcos S; Fernandes, Paula Roquetti; Silva, António José; Dantas, Paulo Silva; Filho, José Fernandes

    2007-01-01

    The influence of genetics on human physique and obesity has been addressed by the literature. Evidence for heritability of anthropometric characteristics has been previously described, mainly for the body mass index (BMI). However, few studies have investigated the influence of genetics on the Heath-Carter somatotype. The aim of the present study was to assess the heritability of BMI and somatotype (endomorphy, mesomorphy, and ectomorphy) in a group of female monozygotic and dizygotic twins from childhood to early adulthood. A total of 28 females aged from 7 to 19 years old were studied. The group included 5 monozygotic and 9 dizygotic pairs of twins. The heritability was assessed by the twin method (h(2)). The anthropometric measures and somatotype were assessed using standard validated procedures. Significant differences between monozygotic and dizygotic pairs of twins were found for height, endomorphy, ectomorphy, and mesomorphy, and the heritability for these measures was high (h(2) between 0.88 and 0.97). No significant differences were found between monozygotic and dizygotic twins for weight, and the BMI and the heritability indexes were lower for these measures (respectively 0.42 and 0.52). The results of the present study have indicated that the somatotype may be more sensible to genetic influences than the BMI in females.

  17. Reproductive factors associated with mammographic density: a Korean co-twin control study.

    Science.gov (United States)

    Sung, Joohon; Song, Yun-Mi; Stone, Jennifer; Lee, Kayoung; Lee, Donghun

    2011-07-01

    To determine the mechanism by which menstrual and reproductive factors are associated with the risk of breast cancer, we examined the relationships between mammographic density and known menstrual and reproductive risk factors for breast cancer. A co-twin control study was conducted with 122 pairs of monozygotic Korean female twins selected from the Healthy Twin study. Mammographic density was measured from digital mammograms using a computer-assisted method. Information on selected menstrual and reproductive factors was collected through a self-administered questionnaire. Within-pair differences for each mammographic measure were regressed against within-pair differences for each menstrual and reproductive risk factor with an adjustment for body mass index and other menstrual and reproductive factors. The percent dense area was inversely associated with the age at the first full-term childbirth (FFTB) and the number of live births, although the associations were marginally significant with an adjustment for BMI and other reproductive factors. The non-dense area was positively associated with the age at the FFTB and the number of live births. The absolute dense area was positively associated with the duration of breast feeding. The age at menarche was not associated with any component of the mammographic measures. This finding suggests that mammographic density can mediate the protective effect of greater parity against breast cancer, at least in part while age at menarche, age at the FFTB, and breast feeding do not exert their effects through mammographic density.

  18. Accounting for the relationship between low education and dementia: a twin study.

    Science.gov (United States)

    Gatz, Margaret; Mortimer, James A; Fratiglioni, Laura; Johansson, Boo; Berg, Stig; Andel, Ross; Crowe, Michael; Fiske, Amy; Reynolds, Chandra A; Pedersen, Nancy L

    2007-09-10

    We evaluated whether the association between low education and greater risk of dementia is explained by genetic influences, using three different types of analyses. The HARMONY study (Swedish for "health" (Hälsa), "genes" (ARv), "environment" (Miljö), "and" (Och), and "new" (NY)) includes members of the Swedish Twin Registry who were aged 65 and older and alive in 1998, and who were screened and clinically assessed for dementia. There were 394 cases with dementia and 7786 unrelated controls. Analyses included co-twin control, tests for association between education and a measured genotype, and bivariate twin modeling. Low education was a significant risk factor for dementia both in case-control analyses (odds ratio=1.77, 95% confidence interval 1.38 to 2.28) and co-twin control analyses with monozygotic twin pairs (odds ratio=3.17, 95% confidence interval 1.26 to 7.93). Apolipoprotein E genotype was not associated with education and did not account for the relationship between education and dementia. Bivariate twin modeling showed that the association between education and dementia was not mediated by genetic influences in common between education and dementia. The association was mediated by shared environmental influences that were related to both dementia and to education. Low education is confirmed as a risk factor for dementia. Findings from three different analytic approaches showed that genetic influences did not explain this association.

  19. Craniofacial skeletal dysplasia of opposite-sex dizygotic twins.

    Science.gov (United States)

    Chou, Szu-Ting; Tseng, Yu-Chuan; Pan, Chin-Yun; Chang, Jenny Zwei-Chieng; Chang, Hong-Po

    2011-05-01

    Craniofacial skeletal dysplasia can lead to different skeletal malocclusions. Both environmental factors and heredity contribute to the formation of malocclusions. There are strong familial tendencies in the development of Angle's Class II and III malocclusions. Cases such as opposite-typed (Class II and III) malocclusions with skeletal and dentoalveolar discordance in siblings or dizygotic (DZ) twins have seldom been reported. We describe the rare case of a pair of opposite-sex DZ twins with completely different skeletal malocclusions, and discuss the clinical considerations for treatment. The patients were twins aged 13 years and 4 months. The girl had mandibular prognathism and a Class III dentoskeletal relationship, whereas the boy had skeletal Class II with mandibular retrusion. Several morphological traits have been implicated with hormonal effect. However, there was no evidence of whether the masculinization effect had any impact on jaw size in the female fetus or whether this effect lasted into adolescence. We suggest that, although DZ twins share the same growth environment, genetic or other unknown extrinsic factors can result in discordance of characteristics of the craniofacial skeleton, dentition, and occlusion. Copyright © 2011 Formosan Medical Association & Elsevier. Published by Elsevier B.V. All rights reserved.

  20. Craniofacial Skeletal Dysplasia of Opposite-sex Dizygotic Twins

    Directory of Open Access Journals (Sweden)

    Szu-Ting Chou

    2011-05-01

    Full Text Available Craniofacial skeletal dysplasia can lead to different skeletal malocclusions. Both environmental factors and heredity contribute to the formation of malocclusions. There are strong familial tendencies in the development of Angle's Class II and III malocclusions. Cases such as opposite-typed (Class II and III malocclusions with skeletal and dentoalveolar discordance in siblings or dizygotic (DZ twins have seldom been reported. We describe the rare case of a pair of opposite-sex DZ twins with completely different skeletal malocclusions, and discuss the clinical considerations for treatment. The patients were twins aged 13 years and 4 months. The girl had mandibular prognathism and a Class III dentoskeletal relationship, whereas the boy had skeletal Class II with mandibular retrusion. Several morphological traits have been implicated with hormonal effect. However, there was no evidence of whether the masculinization effect had any impact on jaw size in the female fetus or whether this effect lasted into adolescence. We suggest that, although DZ twins share the same growth environment, genetic or other unknown extrinsic factors can result in discordance of characteristics of the craniofacial skeleton, dentition, and occlusion.

  1. Leptin and adiponectin levels in discordant dichorionic twins at 72 hours of age-associations with anthropometric parameters and insulin resistance.

    Science.gov (United States)

    Milenković, Svetlana J; Mirković, Ljiljana B; Jovandarić, Miljana Z; Milenković, Dušan M; Banković, Violeta V; Janković, Borisav Z

    2017-04-01

    Insulin resistance (IR) in adults has been associated with intrauterine growth restriction (IUGR). Leptin and adiponectin correlations with anthropometric parameters and IR at 72 h in discordant twins were tested. We included 24 discordant (birth weight discordance ≥20% in relation to the heavier cotwin) and 30 concordant (birth weight discordance ≤10%) twins. A correlation between leptin (but not adiponectin) level and birth weight (BW), birth length and head circumference in IUGR twins was recorded (padiponectin and insulin associated positively. In larger concordant twins' leptin level correlated with HOMA-IR and insulin. Leptin, but not adiponectin, levels correlate positively with anthropometric parameters in IUGR twins. IR in IUGR twins is unrelated to adipokines in the first few days of life.

  2. The season of birth of schizophrenic, neurotic and psychiatrically normal twins.

    Science.gov (United States)

    Kendler, K S

    1982-08-01

    The quarter of birth of 536 schizophrenic, 1,991 neurotic and 12,085 psychiatrically normal twin pairs from the National Academy of Sciences-National Research Council Twin Registry was compared. When either all twin pairs, or only monozygotic or dizygotic twin pairs, were considered, no significant differences were found in the quarter of birth between the 3 groups. No difference in quarter of birth was found for twin pairs concordant versus discordant for schizophrenia. Despite the increased risk for intrauterine and perinatal complications in twin births, schizophrenic twins appear (at least) to be no more vulnerable than schizophrenic singletons to the seasonal gestation and birth-related insults which probably underlie the seasonality in schizophrenic births. Controlling for season of birth probably has little effect on the results of twin studies of schizophrenia.

  3. Recurrence risk for offspring of twins discordant for oral cleft: a population-based cohort study of the Danish 1936-2004 cleft twin cohort

    DEFF Research Database (Denmark)

    Grosen, Dorthe; Bille, Camilla; Pedersen, Jacob Krabbe;

    2010-01-01

    Our objective in this Danish population-based cohort study was to estimate the recurrence risk of isolated oral cleft (OC) for offspring of the unaffected co-twins of OC discordant twin pairs and to compare this risk to the recurrence risk in the offspring of the affected co-twin as well...... as to the risk in the background population. During 1936-2004, 207 twin pairs were ascertained, among whom at least one twin had an OC. The index persons were twins discordant for OC who had children (N=117), and their offspring (N=239). The participants were ascertained by linkage between The Danish Facial...... Cleft Database, The Danish Twin Registry and The Danish Civil Registration System. In the study OC recurrence risk for offspring of the affected and unaffected twin and relative risk were compared to the background prevalence. We found that among 110 children of the 54 OC affected twins, two (1...

  4. 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.

  5. How does the inclusion of twins conceived via fertility treatments influence the results of twin studies?

    Science.gov (United States)

    Burt, S Alexandra; Klump, Kelly L

    2012-12-01

    Rates of twinning have risen dramatically over the last 30 years, from 1 in 53 births in 1980 to 1 in 30 births in 2009 (Martin et al. (January 2012). Three decades of twin births in the United States, 1980-2009. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Health Statistics). This increase is largely attributable to increases in the use of fertility treatments (i.e., ovulation induction and in vitro fertilization) combined with delays in parenthood. Although this increase means that more twins are available for recruitment into twin studies, it also has potential consequences for the heritability estimates obtained in these studies. This study sought to evaluate this possibility, making use of the ongoing Michigan Twins Project (N = 7,261 families with twins aged 3-17 years), an arm of the Michigan State University Twin Registry. Results revealed that, on average, twins conceived via fertility treatments had lower rates of behavior problems than those conceived naturally, although these behavioral differences could be explained largely by demographic and socio-economic differences across the two types of twin families. Twin similarity did not meaningfully differ across fertility treatment status. We thus conclude that estimates of genetic and environmental influences obtained from twin studies over the last 10-15 years are more or less unaffected by the inclusion of twins conceived via fertility treatments in their samples.

  6. Age related-changes in the neural basis of self-generation in verbal paired associate learning

    Directory of Open Access Journals (Sweden)

    Jennifer Vannest

    2015-01-01

    Full Text Available Verbal information is better retained when it is self-generated rather than when it is received passively. The application of self-generation procedures has been found to improve memory in healthy elderly and in individuals with impaired cognition. Overall, the available studies support the notion that active participation in verbal encoding engages memory mechanisms that supplement those used during passive observation. Thus, the objective of this study was to investigate the age-related changes in the neural mechanisms involved in the encoding of paired-associates using a self-generation method that has been shown to improve memory performance across the lifespan. Subjects were 113 healthy right-handed adults (Edinburgh Handedness Inventory >50; 67 females ages 18–76, native speakers of English with no history of neurological or psychiatric disorders. Subjects underwent fMRI at 3 T while performing didactic learning (“read” or self-generation learning (“generate” of 30 word pairs per condition. After fMRI, recognition memory for the second word in each pair was evaluated outside of the scanner. On the post-fMRI testing more “generate” words were correctly recognized than “read” words (p < 0.001 with older adults recognizing the “generated” words less accurately (p < 0.05. Independent component analysis of fMRI data identified task-related brain networks. Several components were positively correlated with the task reflecting multiple cognitive processes involved in self-generated encoding; other components correlated negatively with the task, including components of the default-mode network. Overall, memory performance on generated words decreased with age, but the benefit from self-generation remained consistently significant across ages. Independent component analysis of the neuroimaging data revealed an extensive set of components engaged in self-generation learning compared with didactic learning, and identified

  7. Estimating twin concordance for bivariate competing risks twin data.

    Science.gov (United States)

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

    2014-03-30

    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 experienced 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 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.

  8. Pair correlation and twin primes revisited

    Science.gov (United States)

    Conrey, Brian

    2016-01-01

    We establish a connection between the conjectural two-over-two ratios formula for the Riemann zeta-function and a conjecture concerning correlations of a certain arithmetic function. Specifically, we prove that the ratios conjecture and the arithmetic correlations conjecture imply the same result. This casts a new light on the underpinnings of the ratios conjecture, which previously had been motivated by analogy with formulae in random matrix theory and by a heuristic recipe. PMID:27843409

  9. Pair correlation and twin primes revisited

    Science.gov (United States)

    Conrey, Brian; Keating, Jonathan P.

    2016-10-01

    We establish a connection between the conjectural two-over-two ratios formula for the Riemann zeta-function and a conjecture concerning correlations of a certain arithmetic function. Specifically, we prove that the ratios conjecture and the arithmetic correlations conjecture imply the same result. This casts a new light on the underpinnings of the ratios conjecture, which previously had been motivated by analogy with formulae in random matrix theory and by a heuristic recipe.

  10. A study of asthma severity in adult twins

    DEFF Research Database (Denmark)

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

    2012-01-01

    twins from the Danish Twin Registry, a total of 575 subjects (256 intact pairs and 63 single twins) who themselves and/or their co-twins reported a history of asthma at a questionnaire survey were clinically examined. The severity of asthma symptoms was graded according to a clinical interview...... of asthma symptoms and objectively measured asthma-related traits, respectively, seem to differ. Please cite this paper as: Thomsen SF, van der Sluis S, Kyvik KO and Backer V. A study of asthma severity in adult twins. Clin Respir J 2011; DOI:10.1111/j.1752-699X.2011.00273.x....

  11. Automated twin identification technique for use with electron backscatter diffraction.

    Energy Technology Data Exchange (ETDEWEB)

    Henrie, B. L. (Benjamin Lyman); Mason, T. A. (Thomas A.); Bingert, J. F. (John F.)

    2004-01-01

    Historically, twinning information has been obtained by optical microscopy, TEM, and neutron diffraction. Recent research has shown that automated electron backscatter diffraction (EBSD) can be used to extract reliable twinning statistics. An automated twin identification technique for use with EBSD has facilitated a greater understanding of deformation twinning in materials. The key features of this automated framework are the use of the crystallographic definition of twin relationships, the inclination of the common K, plane at a twin boundary, and the correct identification of the parent orientation in a parent/twin pair. The complex nature of the parent/twin interactions required the use of a voting scheme to correctly identify parent orientations. In those few cases were the voting scheme was unable to determine parent orientation (< 2 pct) the algorithm allows for manual selection. Twin area fractions are categorized by operative twin systems along with secondary and tertiary twinning. These statistics are reported for {alpha}-zirconium and 316L stainless steel. These improved twin statistics can help quantify deformation processes as well as provide validation of plasticity models for materials that exhibit deformation twinning.

  12. 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

    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...... and handedness as covariates. The t-maps (critical threshold value mid R:tmid R: > 6.0, P

  13. 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 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...... 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...

  14. Circadian system heritability as assessed by wrist temperature: a twin study.

    Science.gov (United States)

    Lopez-Minguez, Jesus; Ordoñana, Juan R; Sánchez-Romera, Juan F; Madrid, Juan A; Garaulet, Marta

    2015-02-01

    Previous research shows that wrist temperature (WT) is a good marker to assess the circadian system health in different circumstances. However, no studies have been performed in order to know the genetic component of this circadian marker. For this purpose, the aim was to determine, using classical twin models, the relative genetic and environmental influences on WT. The study was performed in 53 pairs of female twins (28 monozygotic (MZ) and 25 dizygotic (DZ)), with a body mass index 25.9 ± 3.78 and mean age 52 ± 6 years. The sample was selected from the Murcia Twin Register. Circadian patterns were studied by analyzing WT during one week every 10 min "Circadianware®". Genetic influences to WT variability were estimated by comparing correlations of MZ and DZ twin pairs and fitting genetic structural equation models to measured variables. MZ twins showed higher intra-pair correlations than DZ twins for most of the parameters. Genetic factors were responsible for between 46% and 70% of variance (broad sense heritability) in parameters such as mean temperature, mesor, acrophase, Rayleigh test, percentage of rhythmicity and five hours of maximum temperature. The pattern of correlations and the genetic models point to moderate to high heritability for most of the WT parameters, suggesting a relevant genetic influence. The presence of these genetic factors points to endogenicity as the main cause of the coincidence of the WT rhythms. However, some WT parameters are still dependent on environment to a relevant extent and, hence, more amenable to change through external interventions.

  15. Major depressive disorder, suicidal ideation, and suicide attempt in twins discordant for cannabis dependence and early-onset cannabis use.

    Science.gov (United States)

    Lynskey, Michael T; Glowinski, Anne L; Todorov, Alexandre A; Bucholz, Kathleen K; Madden, Pamela A F; Nelson, Elliot C; Statham, Dixie J; Martin, Nicholas G; Heath, Andrew C

    2004-10-01

    Previous research has reported both a moderate degree of comorbidity between cannabis dependence and major depressive disorder (MDD) and that early-onset cannabis use is associated with increased risks for MDD. To examine whether associations between both lifetime cannabis dependence and early cannabis use and measures of MDD, suicidal ideation, and suicide attempt persist after controlling for genetic and/or shared environmental influences. Cross-sectional survey of twin pairs discordant for lifetime cannabis dependence and those discordant for early cannabis use. General population sample of twins (median age, 30 years). Two hundred seventy-seven same-sex twin pairs discordant for cannabis dependence and 311 pairs discordant for early-onset cannabis use (before age 17 years). Self-report measures of DSM-IV-defined lifetime MDD, suicidal ideation, and suicide attempt. Individuals who were cannabis dependent had odds of suicidal ideation and suicide attempt that were 2.5 to 2.9 times higher than those of their non-cannabis-dependent co-twin. Additionally, cannabis dependence was associated with elevated risks of MDD in dizygotic but not in monozygotic twins. Those who initiated cannabis use before age 17 years had elevated rates of subsequent suicide attempt (odds ratio, 3.5 [95% confidence interval, 1.4-8.6]) but not of MDD or suicidal ideation. Early MDD and suicidal ideation were significantly associated with subsequent risks of cannabis dependence in discordant dizygotic pairs but not in discordant monozygotic pairs. Comorbidity between cannabis dependence and MDD likely arises through shared genetic and environmental vulnerabilities predisposing to both outcomes. In contrast, associations between cannabis dependence and suicidal behaviors cannot be entirely explained by common predisposing genetic and/or shared environmental predispositions. Previously reported associations between early-onset cannabis use and subsequent MDD likely reflect shared genetic and

  16. Strong Genetic Contribution to Peer Relationship Difficulties at School Entry: Findings from a Longitudinal Twin Study

    Science.gov (United States)

    Boivin, Michel; Brendgen, Mara; Vitaro, Frank; Dionne, Ginette; Girard, Alain; Perusse, Daniel; Tremblay, Richard E.

    2013-01-01

    This study assessed the genetic and environmental contributions to peer difficulties in the early school years. Twins' peer difficulties were assessed longitudinally in kindergarten (796 twins, "M"[subscript age] = 6.1 years), Grade 1 (948 twins, "M"[subscript age] = 7.1 years), and Grade 4 (868 twins, "M"[subscript…

  17. Confronting Twin Paradox Acceleration

    Science.gov (United States)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  18. Salivary cortisol in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Vinberg, Maj; Bennike, Bente; Kyvik, Kirsten Ohm

    2008-01-01

    -sectional high-risk study. Healthy monozygotic (MZ) and dizygotic (DZ) twins with (High-Risk twins) and without (Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. Awakening and evening salivary cortisol levels were compared between the 190 High- and Low......-Risk twins. The 109 High-Risk twins had significantly higher evening cortisol levels than the 81 Low-Risk MZ twins, also after adjustment for age, sex, and the level of subclinical depressive symptoms. No significant difference was found in awakening cortisol levels between High-Risk and Low-Risk twins....... In conclusion, a high genetic liability to affective disorder was associated with a higher evening cortisol level, but not with awakening cortisol level. Future prospective family, high-risk and twin studies are needed to decide whether abnormalities in the HPA axis can be identified as an endophenotype...

  19. Parental involvement moderates etiological influences on attention deficit hyperactivity disorder behaviors in child twins.

    Science.gov (United States)

    Nikolas, Molly A; Klump, Kelly L; Burt, S Alexandra

    2015-01-01

    Although few would now contest the presence of Gene × Environment (G × E) effects in the development of child psychopathology, it remains unclear how these effects manifest themselves. Alternative G × E models have been proposed (i.e., diathesis-stress, differential susceptibility, bioecological), each of which has notably different implications for etiology. Child twin studies present a powerful tool for discriminating between these models. The current study examined whether and how parental involvement moderated etiological influences on attention deficit hyperactivity disorder (ADHD) within 500 twin pairs aged 6-11 years. Results indicated moderation of genetic and nonshared environmental contributions to ADHD by parental involvement, and moreover, suggested both differential susceptibility and bioecological models of G × E. Results highlight the utility of child twin samples in testing different manifestations of G × E effects.

  20. Heredity-Environment Influences on Growth and Development During Adolescence. A Longitudinal Study of Twins. Studies in Education and Psychology 4.

    Science.gov (United States)

    Fischbein, Siv

    A summary and discussion of a series of studies considered the dilemma that equal educational treatment of all children in public schools appears likely to increase the spread of differences among them in educational achievement. Longitudinal studies of pairs of identical and of fraternal twins in Sweden from 10 to 18 years of age considered the…

  1. Twin database of the secondary school attached to the Faculty of Education of the University of Tokyo: lifecourse database of twins.

    Science.gov (United States)

    Ooki, Syuichi

    2013-02-01

    This article profiles the historical twin databases of the secondary education school attached to the Faculty of Education at the University of Tokyo. The school was established in 1948. Every year, about 50 pairs of twins of all sex and zygosity combinations and aged 11-12 years take an examination, and about 10-20 pairs are admitted based on the results. Three data sets exist: one for applicants (11-12 years), one for junior and senior high school students (12-18 years), and one for graduates (18-79 years). Record linkage of these three databases should facilitate several important research projects; for example, the lifecourse genetic epidemiologic studies and verification of so-called developmental origin of health and disease hypothesis.

  2. Relationship between type 1 diabetes and atopic diseases in a twin population

    DEFF Research Database (Denmark)

    Thomsen, S F; Duffy, D L; Kyvik, K O;

    2011-01-01

    AIM: To study the association between type 1 diabetes and atopic diseases in a twin population. METHODS: We performed record linkage between questionnaire-defined atopic dermatitis, asthma and hay fever, and hospital discharge diagnoses of type 1 diabetes in 54,530 Danish twins, 3-71 years of age....... RESULTS: The age- and sex-adjusted risk of atopic dermatitis was decreased in subjects with type 1 diabetes compared with nondiabetic subjects, (2.1%vs 9.9%), odds ratio (OR)= 0.23 (0.07-0.71), P = 0.011, whereas asthma and hay fever were not significantly associated with type 1 diabetes. Within twin...... pairs discordant for type 1 diabetes, the diabetic twin had a lower risk of atopic dermatitis relative to the nondiabetic co-twin. Genetic factors for atopic dermatitis and type 1 diabetes were negatively correlated (r = -0.30), P = 0.0009. CONCLUSIONS: These findings substantiate the Th1 vs Th2 cell...

  3. Monozygotic twins with Neurofibromatosis type 1, concordant phenotype and synchronous development of MPNST and metastasis

    Directory of Open Access Journals (Sweden)

    Melean German

    2010-08-01

    Full Text Available Abstract Background Neurofibromatosis type 1 is a common autosomal dominant disorder with full penetrance and variable expression. The condition predisposes individuals to the development of malignant nervous system tumours, most frequently Malignant Peripheral Nerve Sheath Tumours (MPNSTs. Previous studies indicate that genetic factors other than mutations in NF1 may be responsible for the condition's variable expression. Case report Here we present data from a pair of monozygotic twins affected by Neurofibromatosis type 1 resulting from a de novo mutation. Both twins developed a left sciatic plexiform neurofibroma that evolved into MPNST at a similar age and they also developed pulmonary metastasis at the same age. Other concordant traits between the twins were: macrocephaly, psychomotor delay, café-au-lait spots, cutaneous neurofibromas, retroperitoneal, pleural and paraspinal neurofibromas. The main discordant features observed were tibial pseudoarthrosis, pectus carinatum, osteoporosis and thymus hyperplasia. Conclusions This is the first report of monozygotic twins with Neurofibromatosis type 1 that develop MPNSTs, the localization and chronological evolution of which, and its metastasis, is concordant in both twins. These cases suggest that the events involved in the transformation of benign plexiform neurofibromas to MPNSTs in Neurofibromatosis type 1, follow a spatiotemporally programme that is influenced by heritable factors other than NF1 mutations.

  4. Twin-twin transfusion syndrome: neurodevelopmental screening test

    Directory of Open Access Journals (Sweden)

    Amabile Vessoni Arias

    2015-03-01

    Full Text Available Objective To assess the neurodevelopmental functions (cognition, language and motor function of survivors of twin-twin transfusion syndrome (TTTS. Method Observational cross-sectional study of a total of 67 monochorionic diamniotic twins who underwent fetoscopic laser coagulation (FLC for treatment of TTTS. The study was conducted at the Center for Investigation in Pediatrics (CIPED, Universidade Estadual de Campinas. Ages ranged from one month and four days to two years four months. Bayley Scales of Infant and Toddler Development Screening Test-III, were used for evaluation. Results Most children reached the competent category and were classified as having appropriate performance. The preterm children scored worse than term infants for gross motor subtest (p = 0.036. Conclusion The majority of children reached the expected development according to their age. Despite the good neurodevelopment, children classified at risk should be monitored for development throughout childhood.

  5. Etiological influences on the stability of autistic traits from childhood to early adulthood: evidence from a twin study.

    Science.gov (United States)

    Taylor, Mark J; Gillberg, Christopher; Lichtenstein, Paul; Lundström, Sebastian

    2017-01-01

    Autism spectrum disorders (ASD) are persistent and lifelong conditions. Despite this, almost all twin studies focus on childhood. This twin study investigated the stability of autistic traits from childhood to early adulthood and explored the degree to which any stability could be explained by genetic or environmental factors. Parents of over 2500 twin pairs completed questionnaires assessing autistic traits when twins were aged either 9 or 12 years and again when twins were aged 18. Bivariate twin analysis assessed the degree of phenotypic and etiological stability in autistic traits across this period. Genetic overlap in autistic traits across development was also tested in individuals displaying a broad ASD phenotype, defined as scoring within the highest 5% of the sample. Autistic traits displayed moderate phenotypic stability (r = .39). The heritability of autistic traits was 76-77% in childhood and 60-62% in adulthood. A moderate degree of genetic influences on childhood autistic traits were carried across into adulthood (genetic correlation = .49). The majority (85%) of the stability in autistic traits was attributable to genetic factors. Genetic influences on autistic traits were moderately stable from childhood to early adulthood at the extremes (genetic correlation = .64). Broad autistic traits display moderate phenotypic and etiological stability from childhood to early adulthood. Genetic factors accounted for almost all phenotypic stability, although there was some phenotypic and etiological instability in autistic traits. Thus, autistic traits in adulthood are influenced by a combination of enduring and unique genetic factors.

  6. DNA stability and schizophrenia in twins.

    Science.gov (United States)

    Nguyen, Giang H; Bouchard, Joseph; Boselli, Monica G; Tolstoi, Linda G; Keith, Louis; Baldwin, Clinton; Nguyen, Nam C; Schultz, Mark; Herrera, Victoria L M; Smith, Cassandra L

    2003-07-01

    The goal of these experiments was to understand DNA changes relevant to schizophrenia. This work compared DNA of monozygotic (MZ) twins surrounding (CAG)(n) repeating sequences, and characterized the relationship between fragile sites and schizophrenia. Twelve twin-pairs, previously classified as MZ and 18 unrelated sib-pairs, from seven families were studied. Eight twin-pairs were affected by schizophrenia, four concordantly and four discordantly. DNA comparisons were made using profiles of electrophoretic size fractionations of PCR amplified (CAG)(n) containing genomic fragments. These profiles were generated by a new method, developed by us, called targeted genomic differential display (TGDD). Surprisingly, the number of peak profile differences in MZ twin-pairs discordant for schizophrenia was greater than the concordantly ill twins and the well twins and, in some cases, overlapped the range of sib-pairs. These results might mean that some twins were not MZ but it was not possible to definitively test these samples for zygosity. Alternatively, the results might be explained as an increased mutation rate (or genomic instability) around (CAG)(n) sites in individuals afflicted with schizophrenia. Also, we uncovered an association of schizophrenia (i.e., a linkage of chromosomal abnormalities and gene localizations) with fragile sites spread throughout the genome (chi(2), P = 0.001). Furthermore, it appears that an increasing number of genes linked to schizophrenia are associated with (CAG)(n) sequences. Fragile sites and (CAG)(n) repeat sequences are known to be unstable. We speculate the association of genomic instability with schizophrenia accounts for seemingly disparate biological and environmental factors that influence disease occurrence. Copyright 2003 Wiley-Liss, Inc.

  7. 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.

  8. 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, N=

  9. 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,

  10. 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, N=

  11. Posttraumatic stress disorder, combat exposure, and carotid intima-media thickness in male twins.

    Science.gov (United States)

    Goetz, Margarethe; Shah, Amit; Goldberg, Jack; Cheema, Faiz; Shallenberger, Lucy; Murrah, Nancy V; Bremner, J Douglas; Vaccarino, Viola

    2014-11-15

    Posttraumatic stress disorder (PTSD) is associated with an increased risk of ischemic heart disease, though the pathophysiologic mechanisms remain unclear. Carotid artery intima-media thickness (CIMT) is a measure of subclinical atherosclerosis. We examined whether PTSD and combat exposure were associated with CIMT in Vietnam War-era twins after controlling for shared genetic and childhood factors. Between 2002 and 2010, we studied 465 middle-aged twins from the Vietnam Era Twin Registry who were free from cardiovascular disease. PTSD was diagnosed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and CIMT was measured by ultrasound. Mixed-effects regression models were used to examine individual, between-pair, and within-pair associations. Approximately 13% of participants met the criteria for PTSD, and 45% served in the Vietnam Theater. PTSD was associated with 32.7 μm higher CIMT (95% confidence interval (CI): 0.9, 64.5) after adjustment for confounders. The average CIMT for the pair increased by 59.7 μm for each additional twin with PTSD (95% CI: 15.9, 104.2). We found no significant within-pair differences in CIMT when comparing PTSD-discordant co-twins. Results for combat exposure were similar, but its association with CIMT weakened after adjustment for PTSD (95% CI: 7.0, 45.3). Among Vietnam War-era veterans, combat exposure and PTSD are associated with CIMT, though the associations are largely mediated by shared childhood factors.

  12. The Roots of Autism and ADHD Twin Study in Sweden (RATSS).

    Science.gov (United States)

    Bölte, Sven; Willfors, Charlotte; Berggren, Steve; Norberg, Joakim; Poltrago, Lina; Mevel, Katell; Coco, Christina; Fransson, Peter; Borg, Jacqueline; Sitnikov, Rouslan; Toro, Roberto; Tammimies, Kristiina; Anderlid, Britt-Marie; Nordgren, Ann; Falk, Anna; Meyer, Urs; Kere, Juha; Landén, Mikael; Dalman, Christina; Ronald, Angelica; Anckarsäter, Henrik; Lichtenstein, Paul

    2014-06-01

    Neurodevelopmental disorders affect a substantial minority of the general population. Their origins are still largely unknown, but a complex interplay of genetic and environmental factors causing disturbances of the central nervous system's maturation and a variety of higher cognitive skills is presumed. Only limited research of rather small sample size and narrow scope has been conducted in neurodevelopmental disorders using a twin-differences design. The Roots of Autism and ADHD Twin Study in Sweden (RATSS) is an ongoing project targeting monozygotic twins discordant for categorical or dimensional autistic and inattentive/hyperactive-impulsive phenotypes as well as other neurodevelopmental disorders, and typically developing twin controls. Included pairs are 9 years of age or older, and comprehensively assessed for psychopathology, medical history, neuropsychology, and dysmorphology, as well as structural, functional, and molecular brain imaging. Specimens are collected for induced pluripotent (iPS) and neuroepithelial stem cells, genetic, gut bacteria, protein-/monoamine, and electron microscopy analyses. RATSS's objective is to generate a launch pad for novel surveys to understand the complexity of genotype-environment-phenotype interactions in autism spectrum disorder and attention-deficit hyperactivity disorder (ADHD). By October 2013, RATSS had collected data from 55 twin pairs, among them 10 monozygotic pairs discordant for autism spectrum disorder, seven for ADHD, and four for other neurodevelopmental disorders. This article describes the design, recruitment, data collection, measures, collected pairs' characteristics, as well as ongoing and planned analyses in RATSS. Potential gains of the study comprise the identification of environmentally mediated biomarkers, the emergence of candidates for drug development, translational modeling, and new leads for prevention of incapacitating outcomes.

  13. Twin Jet

    Science.gov (United States)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  14. Dichorionic Diamniotic Twin Pregnancy Discordant for Bladder Exstrophy

    OpenAIRE

    William Tu; Jane Chueh; William Kennedy

    2009-01-01

    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.

  15. 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.

  16. Relative Genetic and Environmental Contributions to Variations in Human Retinal Electrical Responses Quantified in a Twin Study.

    Science.gov (United States)

    Bhatti, Taha; Tariq, Ambreen; Shen, Ting; Williams, Katie M; Hammond, Christopher J; Mahroo, Omar A

    2017-08-01

    To estimate heritability of parameters of human retinal electrophysiology and to explore which parameters change with age. Prospective, classic twin study. Adult monozygotic and dizygotic twin pairs recruited from the TwinsUK cohort. Electroretinogram responses were recorded using conductive fiber electrodes in response to stimuli incorporating standards set by the International Society for the Clinical Electrophysiology of Vision. These parameters were extracted; in addition, photopic negative-response (PhNR; originating from retinal ganglion cells) and i-wave components were extracted from responses to the photopic single flash. Parameter values were averaged from both eyes. Mean values were calculated for the cohort. Correlation coefficients with age were calculated (averaging parameters from both twins from each pair). Coefficients of intrapair correlation were calculated for monozygotic and dizygotic twins. Age-adjusted heritability estimates were derived using standard maximum likelihood structural equation twin modeling. Responses were recorded from 210 participants in total (59 monozygotic and 46 dizygotic twin pairs). Ninety-three percent were women. Mean age for the cohort was 62.4 years (standard deviation, 11.4 years). In general, response amplitudes correlated negatively, and implicit times positively, with age. Correlations were statistically significant (P 0.35) for the following parameters: scotopic standard and bright-flash a-wave implicit times, photopic 30-Hz flicker and single-flash b-wave implicit times, and PhNR and i-wave implicit times. Intrapair correlations were higher for monozygotic than dizygotic twins, suggesting important genetic influences. Age-adjusted estimates of heritability were significant for all parameters (except scotopic dim-flash b-wave implicit time), ranging from 0.34 to 0.85. Highest estimates were for photopic single-flash a-wave and b-wave amplitudes (0.84 and 0.85, respectively). This study explored heritability of

  17. 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…

  18. Disease-Concordant Twins Empower Genetic Association Studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Li, Weilong; Vandin, Fabio

    2017-01-01

    Genome-wide association studies with moderate sample sizes are underpowered, especially when testing SNP alleles with low allele counts, a situation that may lead to high frequency of false-positive results and lack of replication in independent studies. Related individuals, such as twin pairs...... 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...... 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...

  19. Five-Year Tracking--Investigation on A Pair of Duabetic Twins in the Family and the Early Interventian%五年追踪一对糖尿病双生子的家系调查及早期干预

    Institute of Scientific and Technical Information of China (English)

    韩玉萍; 王洪展; 潘玲; 王米渠

    2009-01-01

    目的 第五年追踪病证结合调查一对糖尿病双生子,研究其含二对双生子家族祖孙三辈的肾虚证、血淤证分布特点.方法 用39 项的肾虚证及四诊量表和19项的血淤量表调查家系3 代15 个成员,并进行糖尿病筛查及糖尿病教育.结果 家系中孙、子、祖三辈的四诊、肾虚症状的平均分以1.5~2.0倍递增.血淤证在家系中具有遗传倾向性,血淤症状明显的儿子,其所生女儿血淤程度最重.除先证者糖尿病双生子外,余家系成员尚未发现糖尿病患者.结论 肾虚证积分可见到随年龄增高而增加的趋势;血淤证有一定的先天(遗传) 背景,似有成群分布状态;糖尿病、肾虚证、血淤证均有一定的家族遗传性,需要早期筛查及干预.%Objective To study the distribution of kidney deficiency and blood stasis in the 3-generations of their family containing two pairs of twins tracking a pair of diabetic twins by combination of disease and syndrome for five years.Methods 15 members of 3-generation pedigree were investigated by kidney deficiency and four diagnosis symptoms questionnaire with 39 items and blood stasis symptoms questionnaire with 19 items.Diabetes screening and diabetes education were carried out in the family.Results The kidney deficiency and four diagnosis symptoms average scores of grandchildren,sons,grandparents generation progressively increased about 1.5~2.0 times.Blood stasis symptoms showed the genetic tendency in the family.One of the sons had the most obvious performance of blood stasis,and his daughter also showed severe blood stasis symptoms.Conclusion Kidney deficiency scores tend to increase with age increased;blood stasis syndrome have a certain degree of innate (genetic) background;diabetes,kidney deficiency,blood stasis syndrome all have certainly inherited the family,and early screening and intervention should be done in the high-risk groups.

  20. Deformation twinning in monazite

    Energy Technology Data Exchange (ETDEWEB)

    Hay, R.S.; Marshall, D.B

    2003-10-20

    Polycrystalline monazite (LaPO{sub 4}) was deformed at room temperature by a spherical indenter. Deformation twins were identified by TEM in 70 grains. Five twin planes were found: (100) was by far the most common; (001) and (120) were less common; (122-bar)was rare, and kinks in (120) twins were identified as irrational '(483)' twin planes. The twinning modes on these planes were inferred from the expression of twinning shear at free surfaces, predictions of classical deformation twinning theory, and various considerations of twin morphology and crystal structure. Atomic shuffle calculations that allow formation of either a glide plane or a mirror plane at the twin interface were used to analyze twin modes. The inferred twin modes all have small atomic shuffles. For (001) twins, the smallest shuffles were obtained with a glide plane at the interface, with displacement vector R=((1)/(2))[010]. The results do not uniquely define a twin mode on (100), leaving open the possibility of more than one mode operating on this plane. Factors that may determine the operative deformation twinning modes are discussed. Crystal structure considerations suggest that the relative abundance of twinning modes may correlate with low shear modulus on the twin plane in the direction of twinning shear, and with a possible low-energy interface structure consisting of a layer of xenotime of one half-unit-cell thickness that could form at (100) and (001) twins. The three most common twins have low strains to low {sigma} coincidence site lattices (CSLs)

  1. The Relation of Maternal Birth Weight to African-American and Non-Latina White Twin Pregnancy Outcomes: A Population-Based Study.

    Science.gov (United States)

    McAndrew, Sarah; Chihara, Izumi; Rankin, Kristin M; Collins, James W

    2016-07-28

    Objectives The authors investigated the association between maternal birth weight and adverse birth outcome as measured by rates of low birth weight (<2500 g, LBW), preterm birth (<37 weeks, PTB), and small for gestational age (weight <10th percentile for gestational age, SGA) among African American and White twin pregnancies. Methods Stratified and multivariable regression analyses were performed on the Illinois transgenerational dataset of non-Latina African American and non-Latina White twin pairs (born 1989-1991) and their mothers (born 1956-1976). Results Former LBW (n = 104) and non-LBW (n = 742) African American mothers had LBW rates in both twins of 76 and 56 %, respectively; RR (95 % CI) = 1.4 (1.2-1.6). Former LBW (n = 105) and non-LBW (n = 2136) White mothers had LBW rates in both twins of 41 and 34 %, respectively; RR = 1.2 (0.9-1.5). In multivariable regression models, the adjusted (controlling for maternal age, education, marital status, parity, prenatal care usage, and cigarette smoking) RR of LBW in both twins among former LBW (compared to non-LBW) African American and White mothers equaled 1.4 (1.2-1.6) and 1.2 (0.9-1.5), respectively. Maternal LBW was associated with a modestly increased risk of PTB but not SGA among African American twin pregnancies: adjusted RR = 1.3 (1.1-1.4) and 1.1 (0.8-1.5), respectively. Conclusions In African American twin pregnancies, maternal LBW is a risk factor for LBW in both twins. Further research is needed to determine whether a similar generational association occurs among non-Latina White twin pregnancies.

  2. 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.

  3. 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.

  4. TWIN GESTATION : A CHALLENGING TASK

    Directory of Open Access Journals (Sweden)

    Vrunda V.

    2015-03-01

    Full Text Available INTRODUCTION In the era of modern obstetrics when multiple pregnancies are on increase it is very important to know the incidence and obstetric outcomes of twin deliveries. Twin pregnancy is still associated with increased maternal and perinatal morbidity and mortality as well as healthcare costs . ( 1 , 2 , 3 MATERIALS AND METHODS : This is a r etrospective study of twin deliveries done in the rural medical college teaching hospital over a period of 3 years. RESULTS : During the study period , incidence of twin delivery was 19.37 per 1000 deliveries. Majority cases of twins were young primies in ag e group (20 - 30 years . Preterm delivery occurred in 68% cases and was therefore , the most common morbidity followed by anaemia (38% and PIH (28%. Most common presentation was vertex (66% and malpresentation were present in 44% of cases. 54% were deliver ed by caesarean section. In 88% second baby delivered within 15 minutes. Uterine inertia , PROM , fetal distress , PPH , cord prolapse and abruption were complications during labour. There was no maternal mortality in present study. Average weight of first baby was 1679.63 gms and 2 nd baby was 1586.94 gms. Perinatal mortality of 1 st baby was 27.55 for 1 st baby and 37.25% for 2 nd baby . Average gestational age for patients in whom cervical encirclage was done was 34 weeks. CONCLUSION: P reterm delivery and low birth weight babies are main challenges to the obstetrician. Incidence of LSCS is quite high with malpresentation of leading (twin A baby is a major indication for LSCS . The use of antenatal care services and good intrapartum mana gement will help improve outcome in twin pregnancies.

  5. The Norwegian Twin Registry.

    Science.gov (United States)

    Nilsen, Thomas S; Brandt, Ingunn; Magnus, Per; Harris, Jennifer R

    2012-12-01

    Norway has a long-standing tradition in twin research, but the data collected in several population-based twin studies were not coordinated centrally or easily accessible to the scientific community. In 2009, the Norwegian Twin Registry was established at the Norwegian Institute of Public Health (NIPH) in Oslo with the purpose of creating a single research resource for Norwegian twin data. As of today, the Norwegian Twin Registry contains 47,989 twins covering birth years 1895-1960 and 1967-1979; 31,440 of these twins consented to participate in health-related research. In addition, DNA from approximately 4,800 of the twins is banked at the NIPH biobank and new studies are continually adding new data to the registry. The value of the Norwegian twin data is greatly enhanced by the linkage opportunities offered by Norway's many nationwide registries, spanning a broad array of medical, demographic, and socioeconomic information.

  6. Danish cohort of monozygotic inflammatory bowel disease twins

    DEFF Research Database (Denmark)

    Moller, Frederik Trier; Knudsen, Lina; Harbord, Marcus

    2016-01-01

    comprised 31 UC, 5 IBDU (IBD unclassified), and 8 CD discordant pairs. In the co-twins not affected by IBD, calprotectin was above 100 μg/g in 2 participants, and above 50 μg/g in a further 5 participants. CONCLUSION: The presented IBD twin cohorts are an excellent resource for bioinformatics studies...

  7. 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.

  8. Genetic and environmental contributions to sleep-wake behavior in 12-year-old twins.

    Science.gov (United States)

    Sletten, Tracey L; Rajaratnam, Shantha M W; Wright, Margaret J; Zhu, Gu; Naismith, Sharon; Martin, Nicholas G; Hickie, Ian

    2013-11-01

    To examine the role of genetic and environmental factors on sleep behavior in 12-year-old twins matched for family environment. Population-based twin cohort. Participants were assessed in their home environment. One hundred thirty-two adolescent twins comprising 25 monozygotic (MZ) and 41 dizygotic (DZ) twin pairs; aged 12.2 ± 0.1 y (mean ± standard deviation). N/A. For 2 weeks in their home environment, participants wore a wrist activity monitor and completed a daily sleep diary. Sleep diaries included reports of bedtime, wake time, and estimated sleep onset time. Mean timing, duration, and quality of sleep during the 2 weeks were calculated for each individual and compared within twin pairs. MZ twin correlations were higher than the DZ correlations for total sleep time (MZr = 0.64; DZr = 0.38) and sleep onset latency (MZr = 0.83; DZr = 0.53) and significantly higher for wake after sleep onset (MZr = 0.66; DZr = 0.04) and sleep efficiency (MZr = 0.82; DZr = 0.10). Univariate modeling showed additive genetic factors accounted for 65% of the variance in total sleep time, 83% in sleep onset latency, and 52% and 57% of the variance in wake after sleep onset and sleep efficiency, respectively. A predominant influence of shared environment was found on the timing of sleep (67% for sleep start time, 86% for sleep end time). There is a strong genetic influence on the sleep-wake patterns of 12-year-old adolescents. Genes have a greater influence on sleep initiation and sleep maintenance and a smaller role in sleep timing, likely to be influenced by family environment.

  9. Risk factors for asthma in young adults: a co-twin control study

    DEFF Research Database (Denmark)

    Thomsen, S F; Ulrik, C S; Kyvik, K O;

    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...... who were initially unaffected with respect to asthma at a nationwide questionnaire-based study in 1994 participated in a similar follow-up study in 2002. Subjects were regarded incident asthma cases when responding affirmatively to the question 'Do you have, or have you ever had asthma'? in 2002....... 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...

  10. Infant Reactivity to Redundant Proprioceptive and Auditory Stimulation: A Twin Study.

    Science.gov (United States)

    Van den Daele, Leland D.

    The role of genetic factors in infant response to redundancy was evaluated through observation of the behavior of three sets of same-sex fraternal twins and six sets of same-sex identical twins to combinations of redundant proprioceptive and auditory stimulation. The twins ranged in age from 6 weeks to 24 weeks. One member of each twin set was…

  11. Promoter methylation of serotonin transporter gene is associated with obesity measures: a monozygotic twin study.

    Science.gov (United States)

    Zhao, J; Goldberg, J; Vaccarino, V

    2013-01-01

    Epigenetic mechanisms are increasingly being recognized as an important factor for obesity. The serotonin transporter gene (SLC6A4) has a critical role in regulating food intake, body weight and energy balance. This study examines the potential association between SLC6A4 promoter methylation and obesity measures in a monozygotic (MZ) twin sample. We studied 84 MZ twin pairs drawn from the Vietnam Era Twin Registry. Obesity measures include body mass index (BMI), body weight, waist circumference (WC) and waist-hip ratio (WHR). The SLC6A4 promoter methylation profile in peripheral blood leukocytes was quantified by bisulfite pyrosequencing. The association between methylation variation and obesity parameters was examined by mixed-model regression and matched pair analysis, adjusting for age, smoking, alcohol consumption, physical activity and total daily energy intake. Multiple testing was controlled using the adjusted false discovery rate (q-value). Mean methylation level was positively correlated with BMI (r=0.29; P=0.0002), body weight (r=0.31; Pobesity within a MZ twin study.

  12. 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...

  13. A Monozygotic Twin Difference Study of Friends' Aggression and Children's Adjustment Problems

    Science.gov (United States)

    Vitaro, Frank; Brendgen, Mara; Boivin, Michel; Cantin, Stephane; Dionne, Ginette; Tremblay, Richard E.; Girard, Alain; Perusse, Daniel

    2011-01-01

    This study used the monozygotic (MZ) twin difference method to examine whether differences in friends' aggression increased the differences in MZ twins' aggression and depressive symptoms from kindergarten to Grade 1 and whether perceived victimization by the friend played a mediating role in this context. Participants were 223 MZ twin pairs.…

  14. 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…

  15. 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...

  16. Twins or two single children

    Directory of Open Access Journals (Sweden)

    2002-08-01

    Full Text Available Based on Swedish register data, we compared the influence of a twin birth on the divorce risk with the influence of the sequential birth of two single children. The divorce risk for a woman with a very young child was lower than the risk for women without children or women with children older than 3.5 years. This behaviour was essentially independent of the number of children and whether or not the woman gave birth to twins. The effect of parity was much smaller than the effect of child age. The influence of twins on the divorce risk appeared to fall between that of a first and a second singleton.

  17. Twin trisomies-Edward and Patau syndromes.

    Science.gov (United States)

    Massiah, Nadine; Griffiths, Emma; Bamigboye, Vincent

    2008-11-01

    To report the rare occurrence of dichorionic diamniotic twins with dissimilar aneuploidies. Case report. District general hospital. A 36-year-old woman conceived by in vitro fertilization. Dichorionic diamniotic twins were found to have elevated nuchal translucencies and cystic hygromas. Intrauterine deaths occurred at 13 and 17 weeks gestation. Medical termination of pregnancy. Karyotypes. Cytogenetic studies confirmed Edward's and Patau's syndromes. The aetiology is unknown but maternal age and in vitro fertilization may be linked since the incidence of aneuploidy rises with maternal age and the incidence of twins' increases with assisted reproductive techniques. This case highlights the need for obstetricians to have good communication and counselling skills.

  18. Twin screw subsurface and surface multiphase pumps

    Energy Technology Data Exchange (ETDEWEB)

    Dass, P. [CAN-K GROUP OF COMPANIES, Edmonton, Alberta (Canada)

    2011-07-01

    A new subsurface twin screw multiphase pump has been developed to replace ESP and other artificial lift technologies. This technology has been under development for a few years, has been field tested and is now going for commercial applications. The subsurface twin screw technology consists of a pair of screws that do not touch and can be run with a top drive or submersible motor; and it carries a lot of benefits. This technology is easy to install and its low slippage makes it highly efficient with heavy oil. In addition twin screw multiphase pumps are capable of handling high viscosity fluids and thus their utilization can save water when used in thermal applications. It also induces savings of chemicals because asphaltenes do not break down easily as well as a reduction in SOR. The subsurface twin screw multiphase pump presented herein is an advanced technology which could be used in thermal applications.

  19. Monozygotic twin differences in non-shared environmental factors associated with chronotype.

    Science.gov (United States)

    Barclay, Nicola L; Eley, Thalia C; Parsons, Michael J; Willis, Thomas A; Gregory, Alice M

    2013-02-01

    Twin studies have highlighted that a large proportion of variability in chronotype is accounted for by individual-specific environmental factors (non-shared environmental influences). However, little research has aimed to identify specific non-shared environmental influences on chronotype. Although epidemiological studies have shed light on possible environmental influences on chronotype, a substantial amount of research has highlighted the importance of genetic influences on exposure toward specific environments, a process termed gene-environment correlation. It is possible that associations between the environment and chronotype are in part determined by genetics, rather than being purely environmental in origin. One way of exploring the contribution of purely non-shared environmental components on associations between chronotype and the environment is to use the monozygotic twin differences design. This design allows us to tease apart the influences of genetics and the environment to identify purely environmental components. One hundred eighty-nine monozygotic twin pairs (mean age 19.81 years, SD = 1.26, range = 18-22 years, 66.1% female) completed the Horne and Östberg Morningness-Eveningness Questionnaire as a measure of chronotype and questionnaires assessing the following candidate non-shared environmental influences: dependent and independent negative life events, educational attainment, employment status, relationship status, deviant peers, affiliation with deviant peers, general health, smoking, drug use, and alcohol use. Linear regression analyses indicated the presence of gene-environment correlation for the majority of associations between chronotype and candidate environmental influences. When controlling for genetic and shared environmental effects, within monozygotic twin-pair differences in chronotype were associated with within monozygotic twin-pair differences in dependent negative life events (β = -0.27, p environmental in nature. The

  20. Genetic and environmental determinants on bone loss in postmenopausal Caucasian women: a 14-year longitudinal twin study.

    Science.gov (United States)

    Zhai, G; Andrew, T; Kato, B S; Blake, G M; Spector, T D

    2009-06-01

    This longitudinal twin study documented that genetic factors explain 44-56% of the between-individual variance in bone loss at femoral neck, lumbar spine, and forearm in postmenopausal Caucasian women, providing a rationale for identifying the specific genes involved. Although there is a significant genetic effect on peak BMD, until recently, no substantive studies on heritability of bone loss in human were available. The aim of the study was to estimate the heritability of the bone loss at multiple sites in postmenopausal Caucasian women. Postmenopausal female monozygotic (MZ) and dizygotic (DZ) twins aged 40 or above at baseline were selected from the TwinsUK registry and followed up for an average of 8 years (range 5-14 years). All twins were noncurrent hormone replacement therapy users and not on any osteoporosis treatment. They had dual-energy X-ray absorptiometry (DXA) scans of their hip, lumbar spine, and forearm several times (range 2-9) during the follow-up period. Individual bone losses at femoral neck, lumbar spine, and forearm were estimated by linear regression modeling. Structural equation modeling was utilized to estimate the heritability of the bone loss. A total of 712 postmenopausal Caucasian female twins (152 MZ and 204 DZ pairs) were included. MZ twins were older and had slightly lower BMD at all sites than DZ twins. DZ twins had slightly higher bone loss at lumbar spine, but similar at femoral neck and forearm compared to MZ twins. Intraclass correlation coefficients (ICC) for the bone loss at all sites were significantly higher in MZ than DZ twin pairs (p = 0.0045, 0.0003, and 0.0007 for femoral neck, lumbar spine, and forearm, respectively), indicating a significant genetic influence on bone loss at these sites. After adjustment for age at baseline and weight change during the follow-up, the heritability estimate was 47% (95% CI 27-63%) for bone loss at femoral neck, 44% (95% CI 27-58%) for lumbar spine, and 56% (95% CI 44-65%) for forearm

  1. Psychological and behavioral problems and related inlfuencing factors in school-age twins%学龄双生子儿童心理行为问题及其影响因素

    Institute of Scientific and Technical Information of China (English)

    杜霞; 李玉玲; 张玉柱; 董河鱼; 丁一

    2015-01-01

    目的:探讨影响学龄双生子儿童心理行为问题的因素,为减少其心理行为问题的发生提供依据。方法采用Achenbach儿童行为量表(CBCL)对内蒙古呼和浩特市147对6~12岁学龄双生子心理行为问题进行调查,运用家庭亲密度与适应性量表(FACESⅡ-CV)和家庭一般情况问卷了解儿童生活环境因素。结果学龄双生子心理行为问题检出率为24.1%,单项行为问题中思维问题检出率(15.3%)最高,身体不适检出率(3.4%)最低。多因素logistic回归分析显示,是否足月产对退缩行为的发生及CBCL总粗分有显著影响(P<0.05),气质类型对思维问题的发生及心理行为问题总检出率有显著影响(P<0.05),父亲生育年龄对思维问题的发生有显著影响(P<0.05),家庭亲密度对违纪行为的发生有显著影响(P<0.05),家庭适应性对思维问题的发生有显著影响(P<0.05),家庭教养方式对社会化问题的发生有显著影响(P<0.05)。结论儿童气质类型、是否足月产、父亲生育年龄、家庭亲密度、适应性及教养方式是影响学龄双生子心理行为问题的主要因素。%ObjectiveTo investigate the inlfuencing factors for psychological and behavioral problems in school-age twins and to provide a basis for reducing the incidence of these problems.MethodsThe psychological and behavioral problems were assessed in 147 pairs of twins aged 6-12 years in Huhhot, China, using the Achenbach Child Behavior Checklist (CBCL). The Family Adaptability and Cohesion Evaluation Scales and Family General Condition Questionnaire were used to collect data.ResultsThe overall detection rate of psychological and behavioral problems in these children was 24.1%; the detection rate of thought problems (15.3%) was the highest, and the detection rate of physical discomforts (3.4%) was the lowest. According to the multiple logistic regression analysis, full-term birth

  2. 6~12岁女童头影测量中下颌形态遗传作用的纵向分析%Longitudinal genetic effects on mandibular morphology in cephalograms of female twins aged six to twelve years old

    Institute of Scientific and Technical Information of China (English)

    袁香玲; 彭静

    2013-01-01

    目的:利用头影测量对混合牙列期的下颌形态作遗传作用的纵向分析.方法:测量89对双生子女童的头颅侧位片.采用混合纵向观察法,最终得到有效双生子对数183对(其中同卵110对,异卵73对).利用双生子法对下颌形态作遗传和环境作用的纵向统计分析.结果:3个下颌实际长度、3个下颌高度、3个下颌深度以及下颌角均检测到显著环境因素作用(P<0.05),而下颌实际长度和下颌高度还能够检测到显著遗传因素作用(P<0.05),下颌体的长度GoPo相对容易改变.结论:下颌的实际大小受较强的遗传控制,但也能够检测到环境因素的显著作用.%Objective:To find the longitudinal genetic effects on mandibular morphology in cephalograms of female twins with mixed dentitions.Methods:The sample used in this study consisted of lateral cephalograms of 89 pairs of female twins aged 6-12 years old in Beijing.With a mixed longitudinal method,the effective twins were 183 (MZ 110,DZ 73).With the statistical methods of twins,the genetic and environmental effects were analyzed on mandibular hard tissue morphology.Results:Statistical comparisons revealed significant environmental effects on 3 measurements of true mandibular length,3 of height,3 of depth and the mandibular angle (P < 0.05),whilst genetic effects on 3 measurements of mandibular length and height were significant (P < 0.05).The length of GoPo was the most subjective to environment change.Conclusion:The effect of genetics on the true mandibular size is strong,while environmental impact also can be founded.

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

    Science.gov (United States)

    Kurushima, Yuko; Ikebe, Kazunori; Matsuda, Ken-Ichi; Enoki, Kaori; Ogata, Soshiro; Yamashita, Motozo; Murakami, Shinya; Maeda, Yoshinobu

    2015-01-01

    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.

  5. Preliminary report of altered insulin secretion pattern in monochorionic twin pregnancies complicated with selective intrauterine growth restriction.

    Science.gov (United States)

    Chang, Yao-Lung; Wang, Tzu-Hao; Abufraijeh, Seham M; Chang, Shuenn-Dyh; Chao, An-Shine; Hsieh, Peter C C

    2017-02-01

    Fetuses with intrauterine growth restriction (IUGR) have adaptive hormonal changes including changes in insulin, which may increase their future risks for developing diabetes mellitus. This study compared cord blood insulin concentrations in IUGR and appropriate for gestational age (AGA) fetuses in a monochorionic (MC) twin model. Ten pairs were classified as selective IUGR (sIUGR) based on having one twin weight below the 10th percentile and with an intertwin birth weight discordance>20%. Fourteen pairs without IUGR were included as a comparison group. Pregnancies with twin-twin transfusion syndrome, congenital structural malformations, and genetic abnormalities were excluded. Insulin and glucose concentrations were measured in cord venous blood at the time of delivery. Cord blood insulin concentrations of sIUGR fetuses were significantly lower than those of AGA counterpart fetuses in MC twins affected by sIUGR (5.1±4.1 mU/L, range: 0.7-9.9 mU/L for sIUGR fetuses and 12.2±7.6 mU/L, range: 3.5-23.7 mU/L for AGA fetuses, p=0.019). No significant difference in insulin concentrations between larger and smaller fetuses in MC twins without IUGR was observed. Insulin concentration was inversely correlated with gestational age of delivery in all fetuses except in those with sIUGR. We did not find any difference in cord blood glucose concentrations between the two fetuses in both groups. Our data show reduced insulin secretion and loss of the physiological decline in concentration over time as gestational age increases in fetuses with sIUGR compared to AGA counterparts. Copyright © 2017 Taiwan Association of Obstetrics & Gynecology. Published by Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Kurushima, Yuko; Ikebe, Kazunori; Matsuda, Ken-ichi; Enoki, Kaori; Ogata, Soshiro; Yamashita, Motozo; Murakami, Shinya; Maeda, Yoshinobu

    2015-01-01

    Objective 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. Subjects and Methods 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. Results 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). Conclusions 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

  7. Methylation matters? Decreased methylation status of genomic DNA in the blood of schizophrenic twins.

    Science.gov (United States)

    Bönsch, Dominikus; Wunschel, Michael; Lenz, Bernd; Janssen, Gesa; Weisbrod, Matthias; Sauer, Heinrich

    2012-08-15

    Studies of schizophrenia inheritance in identical twins show a concordance of about 50%, which supports an epigenetic model. In our present study we investigated methylation of genomic DNA and promoter methylation of Reelin and SOX10 genes in peripheral blood of twins suffering from schizophrenia. Global DNA methylation was reduced (52.3%) in schizophrenic twins if compared with healthy control twins (65.7%). The reduced methylation was significant in males only. We also found a similar hypomethylation in the non-affected twins of discordant pairs and a mixed group of psychiatric controls. In discordant twins there was a relative hypermethylation of the SOX10 promoter. Within-pair-difference of methylation of Reelin promoter was significantly lower in monozygotic twins than in dizygotic twins.

  8. 3D Evaluation of Palatal Rugae in Identical Twins

    Directory of Open Access Journals (Sweden)

    Emiliya Taneva

    2017-01-01

    Full Text Available The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases.

  9. 3D Evaluation of Palatal Rugae in Identical Twins.

    Science.gov (United States)

    Taneva, Emiliya; Evans, Carla; Viana, Grace

    2017-01-01

    The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D) palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases.

  10. 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

    ) 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......High anisotropy in the elastic and plastic properties of hexagonal close-packed (hcp) structured metals not only results in drastic stress variation across grain boundaries, but also heterogeneous distributions within grains. Understanding the mechanism of load sharing between different grains...... becomes more complicated when deformation twinning plays a significant role in accommodating an externally applied load. In this paper, a comprehensive study of stress development in a coarse grained strongly textured hcp polycrystal Zircaloy-2, is given using three-dimensional X-ray diffraction (3DXRD...

  11. Diabetes and Obesity-Related Risks for Pelvic Reconstructive Surgery in a Cohort of Swedish Twins

    OpenAIRE

    Forsman, Mats; Iliadou, Anastasia; Magnusson, Patrik; Falconer, Christian; Altman, Daniel

    2008-01-01

    OBJECTIVE—To determine the diabetes- and obesity-related risks for surgically managed stress urinary incontinence and pelvic organ prolapse. RESEARCH DESIGN AND METHODS—This twin cohort study used the Swedish Twin Register to identify 8,443 female twin pairs born from 1926 through 1958. The association between diabetes and pelvic floor surgery was estimated while taking into account the correlated (twin) structure of the data. RESULTS—For type 1 and type 2 diabetes, no significant association...

  12. Early age of alcohol initiation is not the cause of alcohol use disorders in adulthood, but is a major indicator of genetic risk. A population-based twin study.

    Science.gov (United States)

    Ystrom, Eivind; Kendler, Kenneth S; Reichborn-Kjennerud, Ted

    2014-11-01

    An early age of alcohol initiation (AAI) is associated with and has been hypothesized to be a cause of alcohol use disorders (AUD) in adulthood. Results from twin studies, however, indicate that AAI is an indicator of risk for AUD. We aimed to test a causal hypothesis versus a risk indicator hypothesis for the relationship between early AAI and AUD. A population-based twin study using biometric twin modelling. Norway. A population-based sample of 1336 Norwegian twins. Life-time DSM-IV AUDs were assessed by structured clinical interview and AAI by questionnaire. The risk indicator model in which the association between AAI and AUD was explained by common vulnerability was the best fitted to the data. The heritability was 37% [95% confidence interval (CI) = 21%, 53%] for AAI and 62% (95% CI = 51%, 73%) for AUD. Genetic risk for AAI accounted for 44% (95% CI = 17%, 71%) of the total genetic risk for AUD and the correlation between genetic factors for AAI and AUD was -0.66 (95%CI -0.87, -0.46). Individual-specific environmental risk for AAI explained only 1% (95% CI = 0%, 3%) of the risk for AUD. Shared environmental factors did not influence AUD, but accounted for 25% (95% CI = 7%, 35%) of the variance in AAI. The association between early age of alcohol initiation and alcohol use disorders in later life does not reflect a causal relationship, but is due almost entirely to common genetic risk factors. © 2014 Society for the Study of Addiction.

  13. A Chaotic Home Environment Accounts for the Association between Respect for Rules Disposition and Reading Comprehension: A Twin Study.

    Science.gov (United States)

    Taylor, Jeanette; Hart, Sara A

    2014-10-01

    This study examined the association between socioemotional dispositions from the developmental propensity model and reading comprehension and whether those associations could be accounted for by level of chaos in the home. Data from 342 monozygotic and 333 same-sex dizygotic twin pairs age 7-13 years were used. A parent rated the twins on sympathy, respect for rules, negative emotionality, and daring and level of chaos in the twins' home. Reading comprehension was measured using a state-wide school assessment. Only respect for rules significantly and uniquely predicted reading comprehension. Biometric models indicated that respect for rules was positively associated with reading comprehension via the shared environment and home chaos accounted for a significant amount of that shared environmental variance even after controlling for family income. Children with higher respect for rules have better reading comprehension scores in school and this relationship owes partly to the level of chaos in the family home.

  14. Cerebral asymmetry in twins: predictions of the right shift theory.

    Science.gov (United States)

    Annett, Marian

    2003-01-01

    A study of the heritability of lobar brain volumes in twins has introduced a new approach to questions about the genetics of cerebral asymmetry. In addition to the classic comparison between monozygotic (MZ) and dizygotic (DZ) twins, a contrast was made between pairs of two right-handers (RR pairs) and pairs including one or more non-right-hander (non-RR pairs), in the light of the right shift (RS) theory of handedness. This paper explains the predictions of the RS model for pair concordance for genotype, cerebral asymmetry and handedness in healthy MZ and DZ twins. It shows how predictions for cerebral asymmetry vary between RR and non-RR pairs over a range of incidences of left-handedness. Although MZ twins are always concordant for genotype and DZ twins may be discordant, differences for handedness and cerebral asymmetry are expected to be small, consistent with the scarcity of significant effects in the literature. Marked differences between RR and non-RR pairs are predicted at all levels of incidence, the differences slightly larger in MZ than DZ pairs.

  15. Flexible Twin Open Ring Metro WDM Network

    Institute of Scientific and Technical Information of China (English)

    Susumu Kinoshita; Cechan Tian; Satoru Ohdate; Koji Takeguchi; Yasuhiko Aoki

    2003-01-01

    We have demonstrated a flexible twin open ring WDM network for metro applications. A pair of optical switches in the network keeps the fiber rings open to prevent signal circulation. Traffics are broadcast to every node and selected at the receiving side. Superior transmission and protection switching are proved.

  16. 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...

  17. 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

    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...... in the monozygotic twin pairs. A decrease in gray matter was found in the patients compared with their co-twins and compared with the healthy twins. CONCLUSIONS: The results suggest that the decreases in white matter volume reflect the increased genetic risk to develop schizophrenia, whereas the decreases in gray...

  18. 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.

  19. Familial Risk and Heritability of Cancer Among Twins in Nordic Countries

    Science.gov (United States)

    Mucci, Lorelei A.; Hjelmborg, Jacob B.; Harris, Jennifer R.; Czene, Kamila; Havelick, David J.; Scheike, Thomas; Graff, Rebecca E.; Holst, Klaus; Möller, Sören; Unger, Robert H.; McIntosh, Christina; Nuttall, Elizabeth; Brandt, Ingunn; Penney, Kathryn L.; Hartman, Mikael; Kraft, Peter; Parmigiani, Giovanni; Christensen, Kaare; Koskenvuo, Markku; Holm, Niels V.; Heikkilä, Kauko; Pukkala, Eero; Skytthe, Axel; Adami, Hans-Olov; Kaprio, Jaakko

    2017-01-01

    Importance Estimates of familial cancer risk from population-based studies are essential components of cancer risk prediction. Objective To estimate familial risk and heritability of cancer types in a large twin cohort. Design, Setting, and Participants Prospective study of 80 309 monozygotic and 123 382 same-sex dizygotic twin individuals (N = 203 691) within the population-based registers of Denmark, Finland, Norway, and Sweden. Twins were followed up a median of 32 years between 1943 and 2010. There were 50 990 individuals who died of any cause, and 3804 who emigrated and were lost to follow-up. Exposures Shared environmental and heritable risk factors among pairs of twins. Main Outcomes and Measures The main outcome was incident cancer. Time-to-event analyses were used to estimate familial risk (risk of cancer in an individual given a twin's development of cancer) and heritability (proportion of variance in cancer risk due to interindividual genetic differences) with follow-up via cancer registries. Statistical models adjusted for age and follow-up time, and accounted for censoring and competing risk of death. Results A total of 27 156 incident cancers were diagnosed in 23 980 individuals, translating to a cumulative incidence of 32%. Cancer was diagnosed in both twins among 1383 monozygotic (2766 individuals) and 1933 dizygotic (2866 individuals) pairs. Of these, 38% of monozygotic and 26% of dizygotic pairs were diagnosed with the same cancer type. There was an excess cancer risk in twins whose co-twin was diagnosed with cancer, with estimated cumulative risks that were an absolute 5% (95% CI, 4%-6%) higher in dizygotic (37%; 95% CI, 36%-38%) and an absolute 14% (95% CI, 12%-16%) higher in monozygotic twins (46%; 95% CI, 44%-48%) whose twin also developed cancer compared with the cumulative risk in the overall cohort (32%). For most cancer types, there were significant familial risks and the cumulative risks were higher in monozygotic than dizygotic twins

  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. Intravenous nutrition during a twin pregnancy.

    Science.gov (United States)

    Karamatsu, J T; Boyd, A T; Cooke, J; Vinall, P S; McMahon, M J

    1987-01-01

    A case is reported of a woman in the third trimester of a twin pregnancy who required intravenous nutrition because of inadequate absorption of nutrients due to a jejunoileal bypass. Weight gain was poor, and there was evidence of intrauterine growth retardation before commencement of intravenous feeding. She received overnight intravenous nutrition for 6 weeks and gained weight with ultrasound evidence of fetal growth. During the 33rd week of gestation, she was delivered of healthy twin males who were at appropriate birth weights and development for their age of gestation. The considerations in intravenous nutrition for a twin pregnancy after jejunoileal bypass are discussed.

  2. Differentiating the Use of Gaze in Bilingual-Bimodal Language Acquisition: A Comparison of Two Sets of Twins with Deaf Parents.

    Science.gov (United States)

    Richmond-Welty, E. Daylene; Siple, Patricia

    1999-01-01

    Gaze during utterance was examined in a set of bilingual-bimodal twins acquiring spoken English and American Sign Language (ASL) and a set of monolingual twins acquiring ASL. The bilingual-bimodal twins differentiated their languages by age 3. Like the monolingual twins, the bilingual-bimodal twins established mutual gaze at the beginning of their…

  3. Differentiating the Use of Gaze in Bilingual-Bimodal Language Acquisition: A Comparison of Two Sets of Twins with Deaf Parents.

    Science.gov (United States)

    Richmond-Welty, E. Daylene; Siple, Patricia

    1999-01-01

    Gaze during utterance was examined in a set of bilingual-bimodal twins acquiring spoken English and American Sign Language (ASL) and a set of monolingual twins acquiring ASL. The bilingual-bimodal twins differentiated their languages by age 3. Like the monolingual twins, the bilingual-bimodal twins established mutual gaze at the beginning of their…

  4. Genetic Influences on Reading Difficulties in Boys and Girls: The Colorado Twin Study

    Science.gov (United States)

    Hawke, Jesse L.; Wadsworth, Sally J.; DeFries, John C.

    2006-01-01

    To test the hypothesis that the genetic etiology for reading disability may differ in males and females, data from identical and fraternal twin pairs were analysed using both concordance and multiple regression methods. The sample included 264 identical (129 male, 135 female) and 214 same-sex fraternal (121 male, 93 female) twin pairs in which at…

  5. Genetic and environmental variation in Eysenck Personality Questionnaire scales measured on Australian adolescent twins.

    Science.gov (United States)

    Macaskill, G T; Hopper, J L; White, V; Hill, D J

    1994-11-01

    The Eysenck Personality Questionnaire was administered to 1400 Australian twin pairs aged 11 to 18, and the data were analyzed by a multivariate normal model using the software FISHER. For each scale, attempts were made to transform to normality, about a mean modeled separately for each sex as a quadratic function of age. Variances and covariances were estimated for each sex-zygosity group as a monotone function of age. Evidence for genetic sources of variation were assessed in part by fitting models which allowed for age-dependent, sex-specific, and correlated additive genetic factors, and age-dependent and sex-specific environmental factors, under the assumption that effects of environmental factors common to twin pairs are independent of zygosity. Evidence for genetic factors independent of age and sex was most compelling for Psychoticism and Neuroticism. For Extraversion, if genetic factors exist they would be mostly sex-specific and age-dependent. For the Lie scale there was evidence for, at most, a small component of genetic variation.

  6. 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

    . 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....... 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...

  7. [Influences of genetic and environmental factors on smoking related behaviors among male twin adults in China].

    Science.gov (United States)

    Bao, Z Q; Yu, C Q; Wang, B Q; Cao, W H; Gao, W J; Lyu, J; Wang, S F; Pang, Z C; Cong, L M; Dong, Z; Wu, F; Wang, H; Wu, X P; Wang, D Z; Wang, X J; Wang, B Y; Li, L M

    2016-05-01

    To analyze the influences of genetic and environmental factors on smoking behavior, smoking cessation and onset age of smoking less than 20 years in male twin adults. A face-to-face questionnaire was conducted to collect data from 6 458 pair male twins aged ≥25 years registered in 9 provinces(municipality)in China. The heritability of three smoking related behaviors were calculated by using structural equation models. The ACE models were the best models of the three dimensions of smoking, i.e. smoking behavior, smoking cessation and onset age of smoking less than 20 years for male twins, and the corresponding heritability of these behaviors were 0.26(0.19-0.34), 0.27(0.19-0.37)and 0.05(0.00-0.14), respectively. When adjusted for area and age, the heritability of these three behaviors were 0.26(0.19-0.34), 0.31(0.00-0.74)and 0.05(0.00-0.14), respectively. All the three smoking related behaviors were affected by genetic factors, but environment factors had more effect on them. For smoking cessation, the heritability was highest, but the influence of environmental factors was lowest. Meanwhile, for onset age of smoking, the influence of environmental factors was highest.

  8. The Twin Research Registry at SRI International.

    Science.gov (United States)

    Krasnow, Ruth E; Jack, Lisa M; Lessov-Schlaggar, Christina N; Bergen, Andrew W; Swan, Gary E

    2013-02-01

    The Twin Research Registry (TRR) at SRI International is a community-based registry of twins established in 1995 by advertising in local media, mainly on radio stations and in newspapers. As of August 2012, there are 3,120 same- and opposite-sex twins enrolled; 86% are 18 years of age or older (mean age 44.9 years, SD 16.9 years) and 14% less than 18 years of age (mean age 8.9 years, SD 4.5); 67% are female, and 62% are self-reported monozygotic (MZ). More than 1,375 twins have participated in studies over the last 15 years in collaboration with the University of California Medical Center in San Francisco, the University of Texas MD Anderson Cancer Center, and the Stanford University School of Medicine. Each twin completes a registration form with basic demographic information either online at the TRR Web site or during a telephone interview. Contact is maintained with members by means of annual newsletters and birthday cards. The managers of the TRR protect the confidentiality of twin data with established policies; no information is given to other researchers without prior permission from the twins; and all methods and procedures are reviewed by an Institutional Review Board. Phenotypes studied thus far include those related to nicotine metabolism, mutagen sensitivity, pain response before and after administration of an opioid, and a variety of immunological responses to environmental exposures, including second-hand smoke and vaccination for seasonal influenza virus and Varicella zoster virus. Twins in the TRR have participated in studies of complex, clinically relevant phenotypes that would not be feasible to measure in larger samples.

  9. 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...... twin pairs. They were dosed with metformin to steady state (1 g twice daily) for 6 days and on day 7, the trough concentration of metformin was determined 12 h after the last dose. RESULTS: There was no strong intrapair similarity in trough steady-state plasma concentrations of metformin in either...... dizygotic or monozygotic twin pairs. CONCLUSION: The trough steady-state plasma concentration of metformin does not appear to be tightly genetically regulated. The interpretation of this finding is limited by the small sample size....

  10. Development of the gut microbiota and mucosal IgA responses in twins and gnotobiotic mice.

    Science.gov (United States)

    Planer, Joseph D; Peng, Yangqing; Kau, Andrew L; Blanton, Laura V; Ndao, I Malick; Tarr, Phillip I; Warner, Barbara B; Gordon, Jeffrey I

    2016-06-09

    Immunoglobulin A (IgA), the major class of antibody secreted by the gut mucosa, is an important contributor to gut barrier function. The repertoire of IgA bound to gut bacteria reflects both T-cell-dependent and -independent pathways, plus glycans present on the antibody's secretory component. Human gut bacterial taxa targeted by IgA in the setting of barrier dysfunction are capable of producing intestinal pathology when isolated and transferred to gnotobiotic mice. A complex reorientation of gut immunity occurs as infants transition from passively acquired IgA present in breast milk to host-derived IgA. How IgA responses co-develop with assembly of the microbiota during this period remains poorly understood. Here, we (1) identify a set of age-discriminatory bacterial taxa whose representations define a program of microbiota assembly and maturation during the first 2 postnatal years that is shared across 40 healthy twin pairs in the USA; (2) describe a pattern of progression of gut mucosal IgA responses to bacterial members of the microbiota that is highly distinctive for family members (twin pairs) during the first several postnatal months then generalizes across pairs in the second year; and (3) assess the effects of zygosity, birth mode, and breast feeding. Age-associated differences in these IgA responses can be recapitulated in young germ-free mice, colonized with faecal microbiota obtained from two twin pairs at 6 and 18 months of age, and fed a sequence of human diets that simulate the transition from milk feeding to complementary foods. Most of these responses were robust to diet, suggesting that 'intrinsic' properties of community members play a dominant role in dictating IgA responses. The approach described can be used to define gut mucosal immune development in health and disease states and to help discover ways of repairing or preventing perturbations in this facet of host immunity.

  11. Correlations of heavy flavor pairs in Au-Au collisions at 200 AGeV at RHIC

    CERN Document Server

    Cao, Shanshan; Bass, Steffen A

    2015-01-01

    We study the nuclear modification of angular and momentum correlations between heavy quark pairs in ultra-relativistic heavy-ion collisions. The evolution of heavy quarks inside the thermalized medium is described via a modified Langevin approach that incorporates both elastic and inelastic interactions with the medium constituents. The spacetime evolution of the fireball is obtained from a (2+1)-dimensional viscous hydrodynamics simulation. The hadronization of heavy quarks is performed utilizing a hybrid model of fragmentation and coalescence. Our results show that the nuclear modification of the transverse momentum imbalance of $D\\overline{D}$ pairs reflects the total energy loss experienced by the heavy quarks. The angular correlations of heavy flavor pairs, especially in the low transverse momentum regime, is dominated by the quasi-elastic scatterings between heavy quarks and the medium constituents.

  12. 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 BACKGROUND: 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. METHODS AND FINDINGS: 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. CONCLUSIONS: Our findings emphasize a substantial role of mitochondrial energy- and amino acid metabolism in obesity and development of insulin resistance.

  13. Conjoined twins in the Philippines: experience of a single institution.

    Science.gov (United States)

    Saguil, Esther; Almonte, Josefina; Baltazar, Wilma; Acosta, Alfredo; Caballes, Alvin; Catangui, Antonio; Villegas, Celine

    2009-09-01

    We describe our experience with 22 conjoined twins managed from 1974 to 2006. Records of 22 conjoined twins admitted from 1974 to 2006 were reviewed. Interviews with attending physicians were also conducted. There were 11 thoracopagus, 5 omphalopagus, 3 ischiopagus, 2 craniopagus, and 1 pygopagus twins. Five thoracopagus twins were deemed inseparable due to severe cardiac anomalies. One ischiopagus refused separation, and one craniopagus was separated elsewhere. Six twins (three omphalopagus, one each of pygopagus, ischiopagus, and thoracopagus) were separated emergently as neonates; only one twin is a long-term survivor. Mortalities were due to intractable acidosis, sepsis, and hemorrhage. Nine twins (one craniopagus, one ischiopagus, two omphalopagus, five thoracopagus) were electively separated between 9 months and 2 years of age. One set of these thoracopagus twins died of respiratory failure and sepsis post-operatively. A hydrocephalic twin in another thoracopagus twin died intraoperatively. The rest are alive and well. Emergency separations yielded dismal results due to poor patient conditions; delay in separation allowed progressive deterioration and resultant poor outcome. Elective separation had more favorable results due to well-planned strategies, team preparedness, and better patient conditions. A multi-disciplinary approach, with parental participation, is integral in the holistic management of conjoined twins.

  14. 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...

  15. Recurrence risk for offspring of twins discordant for oral cleft: a population-based cohort study of the Danish 1936-2004 cleft twin cohort.

    Science.gov (United States)

    Grosen, Dorthe; Bille, Camilla; Pedersen, Jacob Krabbe; Skytthe, Axel; Murray, Jeffrey C; Christensen, Kaare

    2010-10-01

    Our objective in this Danish population-based cohort study was to estimate the recurrence risk of isolated oral cleft (OC) for offspring of the unaffected co-twins of OC discordant twin pairs and to compare this risk to the recurrence risk in the offspring of the affected co-twin as well as to the risk in the background population. During 1936-2004, 207 twin pairs were ascertained, among whom at least one twin had an OC. The index persons were twins discordant for OC who had children (N=117), and their offspring (N=239). The participants were ascertained by linkage between The Danish Facial Cleft Database, The Danish Twin Registry and The Danish Civil Registration System. In the study OC recurrence risk for offspring of the affected and unaffected twin and relative risk were compared to the background prevalence. We found that among 110 children of the 54 OC affected twins, two (1.8%) children had OC corresponding to a significantly increased relative risk (RR=10; 95% CI 1.2-35) when compared to the frequency in the background population. Among the 129 children of the 63 unaffected twins, three (2.3%) children were affected, corresponding to a significantly increased relative risk (RR=13; 95% CI 2.6-36) when compared the background prevalence. We concluded that in OC discordant twin pairs similar increased recurrence risks were found among offspring of both OC affected and OC unaffected twins. This provides further evidence for a genetic component in cleft etiology and is useful information for genetic counseling of twin pairs discordant for clefting. Copyright © 2010 Wiley-Liss, Inc.

  16. Reversal of the Detrimental Effects of Post-Stroke Social Isolation by Pair-Housing is Mediated by Activation of BDNF-MAPK/ERK in Aged Mice

    Science.gov (United States)

    Verma, Rajkumar; Harris, Nia M.; Friedler, Brett D.; Crapser, Joshua; Patel, Anita R.; Venna, Venugopal; McCullough, Louise D.

    2016-01-01

    Social isolation (SI) increases stroke-related mortality and morbidity in clinical populations. The detrimental effects of SI have been successfully modeled in the laboratory using young animals. Mechanistically, the negative effects of SI in young animals are primarily mediated by an enhanced inflammatory response to injury and a reduction in neurotrophic factors. However, the response to brain injury differs considerably in the aged. Given that SI is more prevalent in aged populations, we hypothesized that isolation, even when initiated after stroke, would delay recovery in aged mice. We found that aged isolated male mice had significantly increased infarct volume, neurological deficits, and serum IL-6 levels three days after stroke compared to pair housed (PH) mice. Using RT2 Profiler PCR Array and real-time quantitative PCR we found several important synaptic plasticity genes were differentially expressed in post-stroke SI mice. Furthermore, paired mice showed improved memory and neurobehavioral recovery four weeks after injury. Mechanistic and histological studies showed that the beneficial effects of pair housing are partially mediated by BDNF via downstream MAPK/ERK signaling and restoration of axonal basic myelin protein levels. PMID:27125783

  17. Sex ratios provide evidence for monozygotic twinning in the ring-tailed lemur, Lemur catta.

    Science.gov (United States)

    St Clair, John; Campbell-Palmer, Roisin; Lathe, Richard

    2014-02-01

    Monozygotic (MZ) twinning is generally considered to be rare in species other than human. We inspected sex ratios in European zoo-bred ring-tailed lemurs (Lemur catta), revealing a significant excess of same-sex twins. Of 94 pairs, 60 (64%) were either both males or both females (p = .004). Application of the Weinberg differential rule argues that 27% of all twins in this species are MZ pairs. In this protected species, where twinning is commonplace (~50% of newborns are twins), the probable existence of frequent MZ twinning has ramifications for breeding programs aimed to maximize genetic diversity, and suggests that twin studies in a species other than human could have potential as a medical research tool.

  18. Evidence that BMI and type 2 diabetes share only a minor fraction of genetic variance: a follow-up study of 23,585 monozygotic and dizygotic twins from the Finnish Twin Cohort Study.

    Science.gov (United States)

    Lehtovirta, M; Pietiläinen, K H; Levälahti, E; Heikkilä, K; Groop, L; Silventoinen, K; Koskenvuo, M; Kaprio, J

    2010-07-01

    We investigated whether BMI predicts type 2 diabetes in twins and to what extent that is explained by common genetic factors. This was a population-based twin cohort study. Monozygotic (n = 4,076) and dizygotic (n = 9,109) non-diabetic twin pairs born before 1958 answered a questionnaire in 1975, from which BMI was obtained. Information on incident cases of diabetes was obtained by linkage to nationwide registers until 2005. Altogether, 1,332 twins (6.3% of men, 5.1% of women) developed type 2 diabetes. The HR for type 2 diabetes increased monotonically with a mean of 1.22 (95% CI 1.20-1.24) per BMI unit and of 1.97 (95% CI 1.87-2.08) per SD of BMI. The HRs for lean, overweight, obese and morbidly obese participants were 0.59, 2.96, 6.80 and 13.64 as compared with normal weight participants. Model heritability estimates for bivariate variance due to an additive genetic component and non-shared environmental component were 75% (men) and 71% (women) for BMI, and 73% and 64%, respectively for type 2 diabetes. The correlations between genetic variance components (r (g)) indicated that one fifth of the covariance of BMI and type 2 diabetes was due to shared genetic influences. Although the mean monozygotic concordance for type 2 diabetes was approximately twice the dizygotic one, age of onset of diabetes within twin pair members varied greatly, irrespective of zygosity. A 28-year follow-up of adult Finnish twins showed that despite high trait heritability estimates, only a fraction of covariation in BMI and incident type 2 diabetes was of genetic origin.

  19. Conjoined omphalopagus twins: a casereport

    Directory of Open Access Journals (Sweden)

    Sheila Yadira Gómez-Murillo

    2014-11-01

    Full Text Available Multiple pregnancies are 3% of the total. The most frequent are dizygotic females, however, a small group of them are of monozygotic conjoined twins in some anatomical area. This attracts the attention of physicians because of the rarity of the condition and the difficulties as well as the ethical dilemmas for their treatment. We report a case of male Siamese omphalopagus. They were separated surgically at seven weeks of age. One of them lived six months.

  20. Heredity of cognitive functions and personality in twins.

    Science.gov (United States)

    Kalasūnienė, Loreta; Goštautas, Antanas; Sinkus, Algimantas

    2013-01-01

    The inheritance of cognitive functions and personality is still a problem under investigation. A classical method, investigation of twins, is often used to find relative contributions from genetics and the environment to quantitative traits. The aim of this study was to investigate a possible influence of heredity on cognitive functions (by applying the Raven test) and personality traits (according to the Eysenck's theory) in twins. In total, 139 pairs of same-sex twins were investigated. The zygosity of the twin pairs was confirmed through genotyping with 15 molecular DNA markers. Constructive thinking was assessed using the Raven test. Personality assessment was conducted using the Eysenck Personality Questionnaire (EPQ) in Lithuanian. The difference in the total number of incorrect solutions between monozygotic (MZ) and dizygotic (DZ) twin pairs younger than 15 years was not significant; however, in the group older than 15 years, this difference was found to be significant. Based on the total number of incorrect solutions, the concordance in the MZ twins was greater than in the DZ twins. The same tendency was found with cumulative EPQ scores on the extraversion scale. The results imply that the quality of cognitive functions and personality traits (extraversion) can be influenced by heredity. This confirms previous findings on the heritability of cognitive factors and personality traits.

  1. Danish cohort of monozygotic inflammatory bowel disease twins: Clinical characteristics and inflammatory activity

    Science.gov (United States)

    Moller, Frederik Trier; Knudsen, Lina; Harbord, Marcus; Satsangi, Jack; Gordon, Hannah; Christiansen, Lene; Christensen, Kaare; Jess, Tine; Andersen, Vibeke

    2016-01-01

    AIM: To describe the establishment of a Danish inflammatory bowel diseases (IBD) twin cohort with focus on concordance of treatment and inflammatory markers. METHODS: We identified MZ twins, likely to be discordant or concordant for IBD, by merging information from the Danish Twin Register and the National Patient Register. The twins were asked to provide biological samples, questionnaires, and data access to patient files and public registries. Biological samples were collected via a mobile laboratory, which allowed for immediate centrifugation, fractionation, and storage of samples. The mean time from collection of samples to storage in the -80 °C mobile freezer was less than one hour. The diagnoses where validated using the Copenhagen diagnostic criteria. RESULTS: We identified 159 MZ IBD twin pairs, in a total of 62 (39%) pairs both twins agreed to participate. Of the supposed 62 IBD pairs, the IBD diagnosis could be confirmed in 54 pairs. The cohort included 10 concordant pairs, whereof some were discordant for either treatment or surgery. The 10 concordant pairs, where both pairs suffered from IBD, included eight CD/CD pairs, one UC/UC pair and one UC/IBDU pair. The discordant pairs comprised 31 UC, 5 IBDU (IBD unclassified), and 8 CD discordant pairs. In the co-twins not affected by IBD, calprotectin was above 100 μg/g in 2 participants, and above 50 μg/g in a further 5 participants. CONCLUSION: The presented IBD twin cohorts are an excellent resource for bioinformatics studies with proper adjustment for disease-associated exposures including medication and inflammatory activity in the co-twins. PMID:27275097

  2. Disease-Concordant Twins Empower Genetic Association Studies.

    Science.gov (United States)

    Tan, Qihua; Li, Weilong; Vandin, Fabio

    2017-01-01

    Genome-wide association studies with moderate sample sizes are underpowered, especially when testing SNP alleles with low allele counts, a situation that may lead to high frequency of false-positive results and lack of replication in independent studies. Related individuals, such as twin pairs 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 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 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 of an ordinary case-control design, with variations depending on genetic mode. Importantly, the enriched power for dizygotic twins also applies to disease-concordant sibling pairs, which largely extends the application of the concordant twin design. Overall, our simulation revealed a high value of disease-concordant twins in genetic association studies and encourages the use of genetically related individuals for highly efficiently identifying both common and rare genetic variants underlying human complex diseases without increasing laboratory cost. © 2016 John Wiley & Sons Ltd/University College London.

  3. Malaysian Twin Registry.

    Science.gov (United States)

    Jahanfar, Shayesteh; Jaffar, Sharifah Halimah

    2013-02-01

    The National Malaysian Twin Registry was established in Royal College of Medicine, Perak, University Kuala Lumpur (UniKL) in June 2008 through a grant provided by UniKL. The general objective is to facilitate scientific research involving participation of twins and their family members in order to answer questions of health and wellbeing relevant to Malaysians. Recruitment is done via mass media, poster, and pamphlets. We now have 266 adult and 204 children twins registered. Several research projects including reproductive health study of twins and the role of co-bedding on growth and development of children are carried out. Registry holds annual activities for twins and seeks to provide health-related information for twins. We seek international collaboration.

  4. Rate and Outcomes of Pulmonary Stenosis and Functional Pulmonary Atresia in Recipient Twins with Twin-Twin Transfusion Syndrome.

    Science.gov (United States)

    Ortiz, Javier U; Masoller, Narcís; Gómez, Olga; Bennasar, Mar; Eixarch, Elisenda; Lobmaier, Silvia M; Crispi, Fàtima; Gratacos, Eduard; Martinez, Josep María

    2017-01-01

    To evaluate the rate of pulmonary stenosis and functional pulmonary atresia (PS/PA) in recipient twins prior to fetal surgery for twin-twin transfusion syndrome (TTTS) and their pre- and postnatal outcomes. We carried out a prospective study including 260 cases of TTTS. Echocardiography was performed before laser surgery to detect the presence of PS/PA. The outcomes of recipients with and without PS/PA were compared. The need of postnatal cardiac interventions and the survival rate at 6 months of age were also evaluated. PS was observed in 16/260 (6.2%) of recipient twins and PA in 12/260 (4.6%). After fetal surgery, 10/28 (35.7%) recipients died, 9/28 (32.1%) showed in utero regression, and 9/28 (32.1%) had persistence of PS/PA. Postnatally, seven recipients underwent percutaneous balloon pulmonary valvuloplasty, one required surgical valvotomy and one palliative surgery. Pregnancies with recipient twins with PS/PA had lower survival of at least one twin (67.9 vs. 83.6%, p = 0.045) and lower overall survival (57.1 vs. 72.8%, p = 0.015) at 6 months of age. PS and PA were observed in 10.8% of recipients. Among these, about one third showed persistence of pulmonary valve pathology after delivery, which stresses the need for strict follow-up. © 2016 S. Karger AG, Basel.

  5. 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.

  6. Genome-wide analysis of DNA methylation, copy number variation, and gene expression in monozygotic twins discordant for primary biliary cirrhosis

    Directory of Open Access Journals (Sweden)

    Carlo eSelmi

    2014-03-01

    Full Text Available Primary biliary cirrhosis (PBC is an uncommon autoimmune disease with a homogeneous clinical phenotype that reflects incomplete disease concordance in monozygotic (MZ twins. We have taken advantage of a unique collection consisting of genomic DNA and mRNA from peripheral blood cells of female MZ twins (n=3 sets and sisters of similar age (n=8 pairs discordant for disease. We performed a genome-wide study to investigate differences in (i DNA methylation (using a custom tiled 4-plex array containing tiled 50-mers 19,084 randomly chosen methylation sites, (ii copy number variation (CNV (with a chip including markers derived from the 1000 Genomes Project, all three HapMap phases, and recently published studies, and/or (iii gene expression (by whole-genome expression arrays. Based on the results obtained from these three approaches we utilized quantitative PCR to compare the expression of candidate genes. Importantly, our data support consistent differences in discordant twins and siblings for the (i methylation profiles of 60 gene regions, (ii CNV of 10 genes, and (iii the expression of 2 interferon-dependent genes. Quantitative PCR analysis showed that 17 of these genes are differentially expressed in discordant sibling pairs. In conclusion, we report that MZ twins and sisters discordant for PBC manifest particular epigenetic differences and highlight the value of the epigenetic study of twins.

  7. 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

  8. Obesity does not increase the risk of chronic low back pain when genetics are considered. A prospective study of Spanish adult twins.

    Science.gov (United States)

    Dario, Amabile Borges; Loureiro Ferreira, Manuela; Refshauge, Kathryn; Luque-Suarez, Alejandro; Ordoñana, Juan Ramon; Ferreira, Paulo Henrique

    2017-02-01

    Obesity is commonly investigated as a potential risk factor for low back pain (LBP); however, current evidence remains unclear. Limitations in previous studies may explain the inconsistent results in the field, such as the use of a cross sectional design, limitations in the measures used to assess obesity (eg, body mass index-BMI), and poor adjustment for confounders (eg, genetics and physical activity). To better understand the effects of obesity on LBP, our aim was to investigate in a prospective cohort whether obesity-related measures increase the risk of chronic LBP outcomes using a longitudinal design. We assessed obesity through measures that consider the magnitude as well as the distribution of body fat mass. A within-pair twin case-control analysis was used to control for the possible effects of genetic and early shared environmental factors on the obesity-LBP relationship. Data were obtained from the Murcia Twin Registry in Spain. Participants were 1,098 twins, aged 43 to 71 years, who did not report chronic LBP at baseline. Follow-up data on chronic LBP (>6 months), activity-limiting LBP, and care-seeking for LBP were collected after 2 to 4 years. The risk factors were BMI, percentage of fat mass, waist circumference, and waist-to-hip ratio. Sequential analyses were performed using logistic regression controlling for familial confounding: (1) total sample analysis (twins analyzed as independent individuals); (2) within-pair twin case-control analyses (all complete twin pairs discordant for LBP at follow-up); and within-pair twin case-control analyses separated for (3) dizygotic and (4) monozygotic twins. No increase in the risk of chronic LBP was found for any of the obesity-related measures: BMI (men/women, odds ratio [OR]: 0.99; 95 % confidence interval [CI]: 0.86-1.14), % fat mass (women, OR: 0.87; 95% CI: 0.66-1.14), waist circumference (women, OR: 0.98; 95% CI: 0.74-1.30), and waist-to-hip ratio (women, OR: 1.05; 95% CI: 0.81-1.36). Similar results

  9. Muscle dissatisfaction and muscle-enhancing substance use: a population-based twin study in young adult men.

    Science.gov (United States)

    Raevuori, Anu; Keski-Rahkonen, Anna; Rose, Richard J; Rissanen, Aila; Kaprio, Jaakko

    2006-06-01

    In the population-based Finn Twin 16 study, proportions of genetic and environmental factors contributing to muscle dissatisfaction and muscle-enhancing substance use were assessed in 319 pairs of twin brothers: 141 monozygotic (MZ) and 178 dizygotic (DZ) pairs. In addition there were 86 twin individuals from pairs in which only one co-twin responded. Of all respondents, 30% experienced high muscle dissatisfaction. The corresponding proportion of muscle-enhancing substance use was 10%. The subjects were similar in age (23.8 years, 95% confidence interval [CI] 23.76-23.84), body mass index (23.7, 95% CI 23.5-23.9), and waist circumference (84.5 cm, 95% CI 83.7-85.2), independent of their muscle dissatisfaction or muscle-enhancing substance use status and independent of their zygosity. The MZ polychoric correlation for muscle dissatisfaction was .39 (95% CI .17-.58) and .27 for DZ pairs (95% CI .07-.46). The MZ tetrachoric correlation for muscle-enhancing substance use was .65 (95% CI .28-.87) and .56 for DZ pairs (95% CI .26-.78). The AE model, where additive genetic factors (A) accounted for 42% (95% CI .23-.59) and unique environmental factors (E) 58% (95% CI .41-.77) of the liability, provided the best fit for muscle dissatisfaction. The CE model, where common environmental factors (C) accounted for 60% (95% CI .37-.77) and unique environmental factors (E) 40% (95% CI .23-.63) of the liability, provided the best fit for muscle-enhancing substance use. Both genetic and unique (nonfamilial) environmental factors are involved in muscle dissatisfaction in the population. Nongenetic factors (both familial and nonfamilial) appear to best explain the use of muscle-enhancing substances.

  10. 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.)

  11. Heritability of Obesity-related Phenotypes and Association with Adiponectin Gene Polymorphisms in the Chinese National Twin Registry

    NARCIS (Netherlands)

    Lee, Juan; Chen, Li; Snieder, Harold; Chen, Da F.; Lee, Li M.; Liu, Gai F.; Wu, Ting; Tang, Xun; Zhan, Si Y.; Cao, Wei H.; Lv, Jun; Gao, Wen J.; Hu, Yong H.

    P>The purpose of this study was to estimate the heritability of obesity-related phenotypes and investigate the association of adiponectin gene polymorphisms +45T > G and +276G > T with these measures in Chinese twins. 1260 twin pairs were recruited from two cities through the Chinese National Twin

  12. Heritability of Obesity-related Phenotypes and Association with Adiponectin Gene Polymorphisms in the Chinese National Twin Registry

    NARCIS (Netherlands)

    Lee, Juan; Chen, Li; Snieder, Harold; Chen, Da F.; Lee, Li M.; Liu, Gai F.; Wu, Ting; Tang, Xun; Zhan, Si Y.; Cao, Wei H.; Lv, Jun; Gao, Wen J.; Hu, Yong H.

    2010-01-01

    P>The purpose of this study was to estimate the heritability of obesity-related phenotypes and investigate the association of adiponectin gene polymorphisms +45T > G and +276G > T with these measures in Chinese twins. 1260 twin pairs were recruited from two cities through the Chinese National Twin R

  13. 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.

  14. Delivery in Twin Gestation

    Directory of Open Access Journals (Sweden)

    Mark T. Peters

    1995-01-01

    Full Text Available Objective: The objective of this study was to determine whether prophylactic treatment with oral broad-spectrum antimicrobial therapy improves pregnancy outcomes in twin gestations.

  15. Epigenetic drift in the aging genome

    DEFF Research Database (Denmark)

    Tan, Qihua; Heijmans, Bastiaan T; Hjelmborg, Jacob V B

    2016-01-01

    BACKGROUND: Current epigenetic studies on aging are dominated by the cross-sectional design that correlates subjects' ages or age groups with their measured epigenetic profiles. Such studies have been more aimed at age prediction or building up the epigenetic clock of age rather than focusing...... on the dynamic patterns in epigenetic changes during the aging process. METHODS: We performed an epigenome-wide association study of intra-individual longitudinal changes in DNA methylation at CpG (cytosine-phosphate-guanine) sites measured in whole-blood samples of a cohort of 43 elderly twin pairs followed......-wide association studies on a cohort of old twins followed up for 10 years identified highly replicable epigenetic biomarkers predominantly implicated in signalling pathways of degenerative disorders and survival in the elderly....

  16. Dominant Genetic Variation and Missing Heritability for Human Complex Traits: Insights from Twin versus Genome-wide Common SNP Models.

    Science.gov (United States)

    Chen, Xu; Kuja-Halkola, Ralf; Rahman, Iffat; Arpegård, Johannes; Viktorin, Alexander; Karlsson, Robert; Hägg, Sara; Svensson, Per; Pedersen, Nancy L; Magnusson, Patrik K E

    2015-11-05

    In order to further illuminate the potential role of dominant genetic variation in the "missing heritability" debate, we investigated the additive (narrow-sense heritability, h(2)) and dominant (δ(2)) genetic variance for 18 human complex traits. Within the same study base (10,682 Swedish twins), we calculated and compared the estimates from classic twin-based structural equation model with SNP-based genomic-relatedness-matrix restricted maximum likelihood [GREML(d)] method. Contributions of δ(2) were evident for 14 traits in twin models (average δ(2)twin = 0.25, range 0.14-0.49), two of which also displayed significant δ(2) in the GREMLd analyses (triglycerides δ(2)SNP = 0.28 and waist circumference δ(2)SNP = 0.19). On average, the proportion of h(2)SNP/h(2)twin was 70% for ADE-fitted traits (for which the best-fitting model included additive and dominant genetic and unique environmental components) and 31% for AE-fitted traits (for which the best-fitting model included additive genetic and unique environmental components). Independent evidence for contribution from shared environment, also in ADE-fitted traits, was obtained from self-reported within-pair contact frequency and age at separation. We conclude that despite the fact that additive genetics appear to constitute the bulk of genetic influences for most complex traits, dominant genetic variation might often be masked by shared environment in twin and family studies and might therefore have a more prominent role than what family-based estimates often suggest. The risk of erroneously attributing all inherited genetic influences (additive and dominant) to the h(2) in too-small twin studies might also lead to exaggerated "missing heritability" (the proportion of h(2) that remains unexplained by SNPs). Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  17. The adverse prognostic hallmarks in identical twins with Langerhans cell histiocytosis: a clinical report and literature review.

    Science.gov (United States)

    Chai, Damin; Tao, Yisheng; Bao, Zhengqi; Yang, Li; Feng, Zhenzhong; Ma, Li; Liang, Limei; Zhou, Xinwen

    2013-01-01

    Langerhans cell histiocytosis (LCH) is characterized by uncontrolled proliferation of Langerhans cells accompanying eosinophils. It often attacks children under 10 years of age. LCH in identical twins is very rare and its prognosis is different. Here we report identical-twin sisters with LCH. Computed tomography (CT) revealed osteolytic change in each twin's skull, and the elder exhibited poor eyesight. There were massive histiocyte-like cells surrounded by eosinophils in pathologic specimen of the abnormal lesions, which is typical pathologic finding in LCH. These pathologic cells were positive for S-100 and the cell surface protein CD1 antigen (CD1α), the known markers of LCH. After treating them with surgery, no symptoms were seen in the younger until now. While the older was found another soft mass (about 2.0 cm in diameter) in the left temporal area 18 months later. The same treatment was given to the older after admission, and she is healthy to date. To explore the relationship between hallmarks and the prognosis of identical-twin patients with LCH, we retrieved the 16 literatures (16 identical-twin pairs, 31 patients) listed in PubMed during the past 60 years. The data revealed all those patients who have disseminated to the bone marrow, spleen and liver with symptoms of fever and hepatosplenomegaly exhibited worse prognosis (9 out of the 31 patients). The other identical-twin subjects without infiltration of those organs recovered well. In conclusion, this study reveals the adverse hallmarks of prognosis in identical-twin patients with LCH by reviewing relevant literatures.

  18. 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

    2014-07-01

    The longitudinal rank-order stability of cognitive ability increases dramatically over the life span. Theoretical perspectives differ in their emphasis on genetic mechanisms in explaining the longitudinal stability of cognition and how stability changes with development. However, the patterns of stability of genetic and environmental influences on cognition over the life span 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 4,548 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 nonadoptive 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, respectively, low and moderate during early childhood, increased sharply over child development, and remained high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and gradually increased 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 correlation and interaction. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  19. Heritability of Tpeak-Tend Interval and T-wave Amplitude: A Twin Study

    DEFF Research Database (Denmark)

    Haarmark, Christian; Kyvik, Kirsten O; Vedel-Larsen, Esben;

    2011-01-01

    BACKGROUND: -Tpeak-Tend interval (TpTe) and T-wave amplitude (Tamp) carry diagnostic and prognostic information regarding cardiac morbidity and mortality. Heart rate and QT interval are known to be heritable traits. The heritability of T-wave morphology parameters such as TpTe and Tamp is unknown....... TpTe and Tamp were evaluated in a large sample of twins. METHODS AND RESULTS: -Twins from the GEMINAKAR study (611 pairs, 246 monozygotic, 365 dizygotic, aged 38±11 years, 49 % men) who had an ECG performed during 1997-2000 were included. Tamp was measured in leads V1 and V5. Duration variables (RR...... are heritable ECG parameters....

  20. The contribution of diet and genotype to iron status in women: a classical twin study.

    Directory of Open Access Journals (Sweden)

    Susan J Fairweather-Tait

    Full Text Available 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.

  1. 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.

  2. Measuring early or late dependence for bivariate lifetimes of twins

    DEFF Research Database (Denmark)

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

    2015-01-01

    We consider data from the Danish twin registry and aim to study in detail how lifetimes for twin-pairs are correlated. We consider models where we specify the marginals using a regression structure, here Cox's regression model or the additive hazards model. The best known such model is the Clayton...... procedures are applied to Danish twin data to describe dependence in the lifetimes of the twins. Here we show that the early deaths are more correlated than the later deaths, and by comparing MZ and DZ associations we suggest that early deaths might be more driven by genetic factors. This conclusion requires...... models that are able to look at more local dependence measures. We further show that the dependence differs for MZ and DZ twins and appears to be the same for males and females, and that there are indications that the dependence increases over calendar time....

  3. Epigenetic differences arise during the lifetime of monozygotic twins

    Science.gov (United States)

    Fraga, Mario F.; Ballestar, Esteban; Paz, Maria F.; Ropero, Santiago; Setien, Fernando; Ballestar, Maria L.; Heine-Suñer, Damia; Cigudosa, Juan C.; Urioste, Miguel; Benitez, Javier; Boix-Chornet, Manuel; Sanchez-Aguilera, Abel; Ling, Charlotte; Carlsson, Emma; Poulsen, Pernille; Vaag, Allan; Stephan, Zarko; Spector, Tim D.; Wu, Yue-Zhong; Plass, Christoph; Esteller, Manel

    2005-01-01

    Monozygous twins share a common genotype. However, most monozygotic twin pairs are not identical; several types of phenotypic discordance may be observed, such as differences in susceptibilities to disease and a wide range of anthropomorphic features. There are several possible explanations for these observations, but one is the existence of epigenetic differences. To address this issue, we examined the global and locus-specific differences in DNA methylation and histone acetylation of a large cohort of monozygotic twins. We found that, although twins are epigenetically indistinguishable during the early years of life, older monozygous twins exhibited remarkable differences in their overall content and genomic distribution of 5-methylcytosine DNA and histone acetylation, affecting their gene-expression portrait. These findings indicate how an appreciation of epigenetics is missing from our understanding of how different phenotypes can be originated from the same genotype. PMID:16009939

  4. Etiology of the stability of reading difficulties: the longitudinal twin study of reading disabilities.

    Science.gov (United States)

    Astrom, Raven L; Wadsworth, Sally J; DeFries, John C

    2007-06-01

    Results obtained from previous longitudinal studies of reading difficulties indicate that reading deficits are generally stable. However, little is known about the etiology of this stability. Thus, the primary objective of this first longitudinal twin study of reading difficulties is to provide an initial assessment of genetic and environmental influences on the stability of reading deficits. Data were analyzed from a sample of 56 twin pairs, 18 identical (monozygotic, MZ) and 38 fraternal (dizygotic, DZ), in which at least one member of each pair was classified as reading-disabled in the Colorado Learning Disabilities Research Center, and on whom follow-up data were available. The twins were tested at two time points (average age of 10.3 years at initial assessment and 16.1 years at follow-up). A composite measure of reading performance (PIAT Reading Recognition, Reading Comprehension and Spelling) was highly stable, with a stability correlation of .84. Data from the initial time point were first subjected to univariate DeFries-Fulker multiple regression analysis and the resulting estimate of the heritability of the group deficit (h2g) was .84 (+/-.26). When the initial and follow-up data were then fitted to a bivariate extension of the basic DF model, bivariate heritability was estimated at .65, indicating that common genetic influences account for approximately 75% of the stability between reading measures at the two time points.

  5. Twin studies in auto-immune disease.

    Science.gov (United States)

    Leslie, R D; Hawa, M

    1994-01-01

    Immune-mediated diseases affect up to 5% of the population and are a major cause of morbidity and mortality. These diseases can be organ specific, such as insulin-dependent diabetes (IDDM) and non-organ specific, such as Rheumatoid Arthritis (RA). Identical and non-identical twins have been used to establish whether these diseases are determined by genetic or environmental factors. The results of these studies have been collated in a new section of the Mendel Institute in Rome. Diseases included in these studies included IDDM, RA, Systemic Lupus Erythematosus (SLE), Multiple Sclerosis (MS) and Myasthenia. Striking differences in concordance rates between identical and non-identical twins in all these studies suggest that genetic factors are important in causing these diseases. All the diseases are known to be associated with HLA genes on chromosome 6 which may account for some or all of the genetic susceptibility. However, in the majority of pairs the affected twin has an unaffected co-twin. These observations suggest that non-genetically determined factors, probably environmental factors and not somatic mutations, are critical. The study of unaffected co-twins, who are at high disease-risk, has allowed the identification of changes which precede and predict the clinical disease. The immune-mediated destruction in many of these diseases is probably caused by T-lymphocytes. Twin studies have shown the importance of genetic factors in determining T-cell responses. Identical twins should, therefore, provide the perfect test bed to assess the role of T-cells in immune-mediated diseases.

  6. 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...... for carrying beneficial genes and thus are useful samples for gene-longevity association analysis. We conducted a computer simulation to estimate the power of association study using longevity concordant twin pairs. We observed remarkable power increases in using singletons from longevity concordant twin pairs...

  7. 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 θYC 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.

  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

    There has been considerable interest in studying the magnitude and type of inheritance of specific diseases. This is typically derived from family or twin studies, where the basic idea is to compare the correlation for different pairs that share different amount of genes. We here consider data from...... 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. Community structure of age-0 fishes in paired mainstem and created shallow-water habitats in the Lower Missouri River

    Science.gov (United States)

    Starks, T. 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. 

  10. 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 Syst

  11. 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

  12. The 'Planemo' Twins

    Science.gov (United States)

    2006-08-01

    The cast of exoplanets has an extraordinary new member. Using ESO's telescopes, astronomers have discovered an approximately seven-Jupiter-mass companion to an object that is itself only twice as hefty. Both objects have masses similar to those of extra-solar giant planets, but they are not in orbit around a star - instead they appear to circle each other. The existence of such a double system puts strong constraints on formation theories of free-floating planetary mass objects. ESO PR Photo 29a/06 ESO PR Photo 29a/06 Double System of Planetary Mass Objects (Artist's View) Ray Jayawardhana of the University of Toronto (Canada) and Valentin D. Ivanov of ESO report the discovery in the August 3 issue of Science Express, the rapid online publication service of the journal Science. "This is a truly remarkable pair of twins - each having only about one percent the mass of our Sun," said Jayawardhana. "Its mere existence is a surprise, and its origin and fate a bit of a mystery." Roughly half of all Sun-like stars come in pairs. So do about a sixth of brown dwarfs, 'failed stars' that have less than 75 Jupiter masses and are unable to sustain nuclear fusion in their cores. During the past five years, astronomers have identified a few dozen of even smaller free-floating planetary mass objects, or planemos, in nearby star forming regions. Oph 162225-240515, or Oph1622 for short, is the first planemo found to be a double. The researchers discovered the companion candidate in an optical image taken with ESO's 3.5-m New Technology Telescope at La Silla, Chile. They decided to take optical spectra and infrared images of the pair with ESO's 8.2-m Very Large Telescope to make sure that it is a true companion, instead of a foreground or background star that happens to be in the same line of sight. These follow up observations indeed confirmed that both objects are young, at the same distance, and much too cool to be stars. This suggests the two are physically associated. ESO PR

  13. The NAS-NRC Twin Registry of WWII military veteran twins. National Academy of Sciences-National Research Council.

    Science.gov (United States)

    Page, William F

    2002-10-01

    The NAS-NRC Twin Registry is one of the oldest, national population based-twin registries in the United States. It consists of 15,924 white male twin pairs born in the years 1917-1927 (inclusive) both of whom served in the armed forces. The registry, which has been in operation more than 30 years, has collected data from a variety of sources. Records-based, computerized data have come largely from the Department of Veterans Affairs, and there have been three major epidemiologic questionnaires, undertaken roughly every 15 years. Classic twin studies on a variety of medical conditions were the early focus of the registry, which now has a strong focus on chronic disease epidemiology. Work on a DNA specimen bank has been proceeding slowly, but is now a top priority, due to the increasing force of mortality in this twin cohort.

  14. Twin Supergravities from Yang-Mills Squared

    CERN Document Server

    Anastasiou, A; Duff, M J; Hughes, M J; Marrani, A; Nagy, S; Zoccali, M

    2016-01-01

    We consider `twin supergravities' - pairs of supergravities with $\\mathcal{N}_+$ and $\\mathcal{N}_-$ supersymmetries, $\\mathcal{N}_+>\\mathcal{N}_-$, with identical bosonic sectors - in the context of tensoring super Yang-Mills multiplets. It is demonstrated that the pairs of twin supergravity theories are related through their left and right super Yang-Mills factors. This procedure generates new theories from old. In particular, the matter coupled $\\mathcal{N}_-$ twins in $D=3,5,6$ and the $\\mathcal{N}_-=1$ twins in $D=4$ have not, as far as we are aware, been obtained previously using the double-copy construction, adding to the growing list of double-copy constructible theories. The use of fundamental matter multiplets in the double-copy construction leads us to introduce a bi-fundamental scalar that couples to the well-known bi-adjoint scalar field. It is also shown that certain matter coupled supergravities admit more than one factorisation into left and right super Yang-Mills-matter theories.

  15. A prospective study of twinning and perinatal mortality in urban Guinea-Bissau

    Science.gov (United States)

    2012-01-01

    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 twin mortality. Male sex (RR = 1.38, CI: 0.97-1.96), unawareness of twin pregnancy (RR = 1.64, CI: 0.97-2.78) and high blood pressure during pregnancy (RR = 1.77, CI: 0.88-3.57) were borderline non-significant. Sixty-five percent (245/375) of the mothers who delivered at the hospital were unaware of their twin pregnancy. Conclusions Twins had a very high perinatal mortality, three-fold higher than singletons. A birth weight twin pregnancy was common. Urgent interventions are needed to lower perinatal twin mortality in Guinea-Bissau. PMID:23216795

  16. 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....... In addition, type 2 diabetes incidence cases in twins (n = 626) and singletons (n = 553) were identified through the National Diabetes Register. RESULTS: Twins were more abdominally obese, insulin resistant, and glucose intolerant, as evidenced by a higher A1C (%) (means +/- SD) (MZ: 6.0 +/- 1.0, DZ: 5...

  17. [Study of intellectual activity in twins. I. Developmental features].

    Science.gov (United States)

    Kantonistova, N S

    1980-01-01

    The investigation of 234 twins and 100 singletons at the age from 7 till 16 years old was carried out by WISC method. The intellectual development of twins was established to fall behind singletons at the expense of lower level of verbal intellectual functions. It is due to organic changes of nervous system, arising as the result of the action of unfavourable factors during antenatal period. Slight asphyxia and prematurity as well as the order of birth do not exert essential effect on intellectual development of twins. Low weight at birth combines with lower intellectual index only in cases when lowering of weight is due to the action of unfavourable factors during intrauterine period. "Twins situation" apparently renders positive influence on twins intellectual activity during school are, distracting children's attention in cases of unfavourable psychological situation in family. Intellectual environment renders positive influence on intellectual development of twins.

  18. Coffee and smoking as risk factors of twin pregnancies

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Bech, Bodil Hammer; Christensen, Kaare

    2007-01-01

    Twinning rates have changed substantially over time for reasons that are only partly known. In this study we studied smoking, coffee and alcohol intake, and their possible interaction with obesity as potential determinants of twinning rates using data from the Danish National Birth Cohort between...... their prepregnancy weight and height, coffee and alcohol intake, smoking habits, and potential confounding factors at early stages of pregnancy. We identified smoking (> 10 cigarettes/day) as a possible determinant of twinning, particularly for dizygotic twinning rates (same sex) and furthermore corroborated...... that obesity and the mother's age are strong correlates of twinning. Others have found coffee intake to increase twinning rates but that is not seen in these data....

  19. Twin Reversed Arterial Perfusion Sequence: A Rare Entity

    Science.gov (United States)

    Khanduri, Sachin; Chhabra, Saakshi; Raja, Anshul; Bhagat, Saurav

    2015-01-01

    Twin reversed arterial perfusion (TRAP) sequence is an extremely rare complication of monochorionic multi-fetal pregnancy, occurring once in 35,000 births. This condition is characterized by a malformed fetus without a cardiac pump being perfused by a structurally normal (pump) twin via an artery-to-artery anastomosis in a reverse direction. We report a case of a primigravida, who came for routine antenatal checkup to our hospital at 31 weeks gestational age. Ultrasound imaging and magnetic resonance imaging revealed twin monochorionic intrauterine pregnancy with a viable, normal-appearing first twin and amorphous structured second twin connected by umbilical vessels. The patient was monitored with weekly ultrasonography, echocardiography, and Doppler ultrasound examination to ascertain the well-being of the pump twin. She delivered successfully at term a normal live baby and an acardius acephalus fetus. Plain X-ray of the acardius acephalus fetus confirmed the absence of cephalic structures. The perinatal mortality of the pump twin ranges from 35 to 55%; hence, it is essential to diagnose the presence of a pump twin at an early gestational age through improved imaging techniques, so that intervention can be planned early in the pregnancy for a better outcome of the pump twin. PMID:25861543

  20. Perinatal risk factors and neonatal complications in discordant twins admitted to the neonatal intensive care unit

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-rui; LIU Jie; ZENG Chao-mei

    2013-01-01

    Background Many studies have shown a relationship between birth weight discordance and adverse perinatal outcomes.This study aimed to investigate the perinatal risk factors and neonatal complications of discordant twins who are admitted to the neonatal intensive care unit.Methods A total of 87 sets of twins were enrolled in this retrospective study,of which 22 sets were discordant twins and 65 sets were concordant twins.Binary Logistic regression analysis was used to identify the risk factors associated with the occurrence of discordant twins.The common neonatal complications of discordant twins were also investigated.Results Multivariate analysis showed that the use of assisted reproductive techniques,pregnancy-induced hypertension,and unequal placental sharing were risk factors for the occurrence of discordant twins.The incidence of small for gestational age infants and very low birth weight infants of discordant twins was significantly higher,while the birth weight of discordant twins was significantly lower than those of concordant twins.The duration of hospitalization of discordant twins was longer than that of concordant twins.The incidence of several neonatal complications,such as neonatal respiratory distress syndrome and intracranial hemorrhage,was higher in discordant twins than that in concordant twins.The percentage of those requiring pulmonary surfactant and mechanical ventilation was significantly higher in discordant twins than that in concordant twins.Conclusions Use of assisted reproductive techniques,pregnancy-induced hypertension,and unequal placental sharing are perinatal risk factors of discordant twins who are admitted to the neonatal intensive care unit.These infants are also much more likely to suffer from various neonatal complications,especially respiratory and central nervous system diseases.It is important to prevent the occurrence of discordant twins by decreasing these risk factors and timely treatment should be given to discordant

  1. Exploring the Co-Development of Reading Fluency and Reading Comprehension: A Twin Study.

    Science.gov (United States)

    Little, Callie W; Hart, Sara A; Quinn, Jamie M; Tucker-Drob, Elliot M; Taylor, Jeanette; Schatschneider, Christopher

    2016-11-10

    This study explores the co-development of two related but separate reading skills, reading fluency and reading comprehension, across Grades 1-4. A bivariate biometric dual change score model was applied to longitudinal data collected from 1,784 twin pairs between the ages of 6 and 10 years. Grade 1 skills were influenced by highly overlapping genetic and environmental factors. Growth in both skills was influenced by highly overlapping shared environmental factors. Cross-lagged parameters indicated bidirectional effects, with stronger effects from fluency to comprehension change than from comprehension to fluency change.

  2. 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

  3. Tidally-Triggered Star Formation in Close Pairs of Galaxies 2 Constraints on Burst Strengths and Ages

    CERN Document Server

    Gillespie, E B; Kenyon, S J; Gillespie, Elizabeth Barton; Geller, Margaret J.; Kenyon, Scott J.

    2003-01-01

    Galaxy-galaxy interactions rearrange the baryons in galaxies and trigger substantial star formation; the aggregate effects of these interactions on the evolutionary histories of galaxies in the Universe are poorly understood. We combine B and R-band photometry and optical spectroscopy to estimate the strengths and timescales of bursts of triggered star formation in the centers of 190 galaxies in pairs and compact groups. Based on an analysis of the measured colors and EW(H-alpha), we characterize the pre-existing and triggered populations separately. The best-fitting burst scenarios assume stronger reddening corrections for line emission than for the continuum and continuous star formation lasting for \\gtrsim a hundred Myr. The most realistic scenarios require an initial mass function that is deficient in the highest-mass stars. The color of the pre-existing stellar population is the most significant source of uncertainty. Triggered star formation contributes substantially (probably >= 50%) to the R-band flux...

  4. Testing putative causal associations of risk factors for early intercourse in the study of twin adults: genes and environment (STAGE).

    Science.gov (United States)

    Donahue, Kelly L; D'Onofrio, Brian M; Lichtenstein, Paul; Långström, Niklas

    2013-01-01

    Adverse childhood experiences and substance use have been identified as potential causal risk factors for early-onset sexual intercourse. While it is possible that exposure to these risk factors directly increases the likelihood of engaging in early intercourse, an alternative explanation is that observed associations between these variables are due to shared familial confounds. These unmeasured confounds may increase the likelihood of being exposed to these risk factors and of engaging in early intercourse. Participants drawn from a population-based study of Swedish adult twins (ages 19-47 years; N = 12,126) reported on their history of exposure to early physical and sexual trauma, cigarette use, and cannabis use. We investigated the nature of the association between these risk factors and young age at first intercourse, using a comparison of twins differentially exposed to each risk factor. When compared to non-exposed, unrelated individuals, participants who reported adverse childhood experiences or who engaged in early cigarette use or cannabis use were more likely to engage in early intercourse. However, co-twin comparisons indicated that observed associations between these risk factors and early intercourse may be due to familial factors shared within twin pairs, and risk factor exposure may not lead directly to early intercourse. Our results suggest that preventing trauma exposure or preventing or delaying adolescents' cigarette smoking or cannabis use may not effectively delay intercourse onset; instead, other aspects of the adolescent's environment should be addressed.

  5. The formation of twinned austenite in Fe-10Cr-10Ni-2W maraging steel

    Energy Technology Data Exchange (ETDEWEB)

    Suk, J.I.; Hong, S.H.; Nam, S.W. (Dept. of Minerals Science and Engineering, Korea Advanced Inst. of Science and Technology, P.O. Box 150, Cheongyang, Seoul (KR))

    1991-12-01

    The precipitation hardening mechanisms in high strength maraging steels have been studied in detail by many investigators, but limited information is available on the formation of austenite during aging. Some investigations have been concerned with the understanding of the effect of reverted austenite formed during aging on the mechanical properties. However, only a few investigations have been reported on the morphology and crystallographic feature of austenite. Shiang and Wayman first reported the twin-related and coupled morphology of Widmanstatten austenite plates which were frequently observed in maraging steel. In addition, Ameyama et al. reported the morphology and crystallographic features of austenite formed in ferrite grain during aging in a two-phase stainless steel, and found that each side of the austenite pair of twins satisfies the Kurdjumov-Sachs (K-S) orientation relationship with the parent phase. The morphology and crystallographic features of the reverted austenite formed during aging of Fe-10Cr-10Ni-2W stainless maraging steel have been investigated in this paper. The major strengthening precipitate in Fe-10Cr-10Ni-2W maraging steels has been identified as the rod-shaped {eta}-Ni{sub 3}Ti phase in our previous study. The peculiar morphology of the austenite, i.e., twinned austenite, also has been found in our studies of maraging steel in the Fe-10Cr-10Ni-2W lath martensite. In addition, computer simulation of the diffraction pattern is used to confirm the orientation relationships, such as the Kurdjumov-Sachs (K-S) relationship, the Nishiyama-Wasserman (N-W) relationship and the twin relationship by comparisons with the experimentaly observed results.

  6. Prospective Risk of Stillbirth and Neonatal Complications in Twin Pregnancies : Systematic Review and Meta-analysis

    NARCIS (Netherlands)

    Cheong-See, Fiona; Schuit, Ewoud; Arroyo-Manzano, David; Khalil, Asma; Barrett, Jon; Joseph, K. S.; Asztalos, Elizabeth; Hack, Karien; Lewi, Liesbeth; Lim, Arianne; Liem, Sophie; Norman, Jane E.; Morrison, John; Combs, C. Andrew; Garite, Thomas J.; Maurel, Kimberly; Serra, Vicente; Perales, Alfredo; Rode, Line; Worda, Katharina; Nassar, Anwar; Aboulghar, Mona; Rouse, Dwight; Thom, Elizabeth; Breathnach, Fionnuala; Nakayama, Soichiro; Russo, Francesca Maria; Robinson, Julian N.; Dodd, Jodie M.; Newman, Roger B.; Bhattacharya, Sohinee; Tang, Selphee; Mol, Ben Willem J; Zamora, Javier; Thilaganathan, Basky; Thangaratinam, Shakila

    2017-01-01

    Twin pregnancies are at increased risk of stillbirth. Uncomplicated twin pregnancies are commonly delivered earlier to prevent stillbirth; however, there is a risk of neonatal complications associated with being born prior to 39 weeks’ gestation. The optimal gestational age for delivery in twin

  7. 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 

  8. SUSY Meets Her Twin

    CERN Document Server

    Katz, Andrey; Pokorski, Stefan; Redigolo, Diego; Ziegler, Robert

    2016-01-01

    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.

  9. SUSY Meets Her Twin

    CERN Document Server

    Katz, Andrey; Pokorski, Stefan; Redigolo, Diego; Ziegler, Robert

    2017-01-01

    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.

  10. SUSY Meets Her Twin

    CERN Document Server

    Katz, Andrey; Pokorski, Stefan; Redigolo, Diego; Ziegler, Robert

    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.

  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. Association between dietary fat intake and insulin resistance in Chinese child twins.

    Science.gov (United States)

    Huang, Tao; Beaty, Terri; Li, Ji; Liu, Huijuan; Zhao, Wei; Wang, Youfa

    2017-01-01

    Dietary fat intake is correlated with increased insulin resistance (IR). However, it is unknown whether gene-diet interaction modulates the association. This study estimated heritability of IR measures and the related genetic correlations with fat intake, and tested whether dietary fat intake modifies the genetic influence on type 2 diabetes (T2D)-related traits in Chinese child twins. We included 622 twins aged 7-15 years (n 311 pairs, 162 monozygotic (MZ), 149 dizygotic (DZ)) from south-eastern China. Dietary factors were measured using FFQ. Structural equation models were fit using Mx statistical package. The intra-class correlation coefficients for all traits related to T2D were higher for MZ twins than for DZ twins. Dietary fat and fasting serum insulin (additive genetic correlation (r A) 0·20; 95 % CI 0·08, 0·43), glucose (r A 0·12; 95 % CI 0·01, 0·40), homoeostasis model of assessment-insulin resistance (Homa-IR) (r A 0·22; 95 % CI 0·10, 0·50) and the quantitative insulin sensitivity check index (Quicki) (r A -0·22; 95 % CI -0·40, 0·04) showed strong genetic correlations. Heritabilities of dietary fat intake, fasting glucose and insulin were estimated to be 52, 70 and 70 %, respectively. More than 70 % of the phenotypic correlations between dietary fat and insulin, glucose, Homa-IR and the Quicki index appeared to be mediated by shared genetic influence. Dietary fat significantly modified additive genetic effects on these quantitative traits associated with T2D. Analysis of Chinese twins yielded high estimates of heritability of dietary fat intake and IR. Genetic factors appear to contribute to a high proportion of the variance for both insulin sensitivity and IR. Dietary fat intake modifies the genetic influence on blood levels of insulin and glucose, Homa-IR and the Quicki index.

  13. Alcohol consumption at midlife and risk of stroke during 43 years of follow-up: cohort and twin analyses.

    Science.gov (United States)

    Kadlecová, Pavla; Andel, Ross; Mikulík, Robert; Handing, Elizabeth P; Pedersen, Nancy L

    2015-03-01

    Although alcohol-stroke association is well known, the age-varying effect of alcohol drinking at midlife on subsequent stroke risk across older adulthood has not been examined. The effect of genetic/early-life factors is also unknown. We used cohort and twin analyses of data with 43 years of follow-up for stroke incidence to help address these gaps. All 11 644 members of the population-based Swedish Twin Registry born 1886 to 1925 with alcohol data aged ≤60 years were included. The interaction of midlife alcohol consumption by age at stroke was evaluated in Cox-regression and analyses of monozygotic twins were used. Covariates were baseline age, sex, cardiovascular diseases, diabetes mellitus, stress reactivity, depression, body mass index, smoking, and exercise. Altogether 29% participants developed stroke. Compared with very-light drinkers (2 drinks/d) had greater risk of stroke (hazard ratio, 1.34; P=0.02) and the effect for nondrinkers approached significance (hazard ratio, 1.11; P=0.08). Age increased stroke risk for nondrinkers (P=0.012) and decreased it for heavy drinkers (P=0.040). Midlife heavy drinkers were at high risk from baseline until the age of 75 years when hypertension and diabetes mellitus grew to being the more relevant risk factors. In analyses of monozygotic twin-pairs, heavy drinking shortened time to stroke by 5 years (P=0.04). Stroke-risk associated with heavy drinking (>2 drinks/d) in midlife seems to predominate over well-known risk factors, hypertension and diabetes, until the age of ≈75 years and may shorten time to stroke by 5 years above and beyond covariates and genetic/early-life factors. Alcohol consumption should be considered an age-varying risk factor for stroke. © 2015 American Heart Association, Inc.

  14. The response to oxidative stress and metallomics analysis in a twin study: The role of the environment.

    Science.gov (United States)

    Medda, Emanuela; Minoprio, Anna; Nisticò, Lorenza; Bocca, Beatrice; Simonelli, Valeria; D'Errico, Mariarosaria; Calcagnile, Angelo; Giuliani, Alessandro; Toccaceli, Virgilia; Minghetti, Luisa; Alimonti, Alessandro; Stazi, Maria Antonietta; Mazzei, Filomena; Dogliotti, Eugenia

    2016-08-01

    Inefficient response to oxidative stress has been associated with ageing and health risk. Metals are known to inhibit DNA repair and may modify the antioxidant response. How genetic variability and lifestyle factors modulate the response to oxidative stress is poorly explored. Our study aims to disentangle the contribution of genetics and environmental exposures to oxidative stress response using data from twin pairs. The non-enzymatic antioxidant capacity (NEAC), the repair capacity of 8-oxo-7,8-dihydroguanine (OGG activity) and the levels of 12 metals were measured in blood of 64 monozygotic and 31 dizygotic twin pairs. The contributions of genetic and environmental effects were assessed using standard univariate twin modelling. NEAC and OGG activity significantly decreased with age. Gender-, age- and body mass index-associated differences were identified for some metals. Principal Component Analysis identified two groups of metals whose levels in blood were highly correlated: As, Hg, Pb, Se, Zn and Al, Co, Cr, Mn, Ni. The environmental influence was predominant on OGG activity and NEAC variance whereas for most metals the best-fitting model incorporated additive genetic and unique environmental sources of variance. NEAC and OGG activity were both inversely correlated with blood levels of various metals. The inhibition of OGG activity by Cd was largely explained by smoking. Our data show a substantial role of environmental factors in NEAC and OGG activity variance that is not explained by twins' age. Exogenous environmental factors such as metals contribute to oxidative stress by decreasing NEAC and inhibiting repair of oxidatively-induced DNA damage.

  15. A biometric latent curve analysis of memory decline in older men of the NAS-NRC twin registry.

    Science.gov (United States)

    McArdle, John J; Plassman, Brenda L

    2009-09-01

    Previous research has shown cognitive abilities to have different biometric patterns of age-changes. We examined the variation in episodic memory (word recall task) for over 6,000 twin pairs who were initially aged 59-75, and were subsequently re-assessed up to three more times over 12 years. In cross-sectional analyses, variation in the number of words recalled independent of age was explained largely by non-shared influences (65-72%), with clear additive genetic influences (12-32%), and marginal shared family influences (1-18%). The longitudinal phenotypic analysis of the word recall task showed systematic linear declines over age, but several nonlinear models with more dramatic changes at later ages, improved the overall fit. A two-part spline model for the longitudinal twin data with an optimal turning point at age 74 led to: (a) a separation of non-shared environmental influences and transient measurement error (~50%); (b) strong additive genetic components of this latent curve (~44% at age 60) with increases (over 50%) up to age 74, but with no additional genetic variation after age 74; (c) the smaller influences of shared family environment (~15% at age 74) were constant over all ages; (d) non-shared effects play an important role over most of the life-span but diminish after age 74.

  16. 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...

  17. Twinning behavior of polycrystalline alpha-uranium under quasi static compression

    Science.gov (United States)

    Zhou, Ping; Xiao, Dawu; Wang, Wenyuan; Sang, Ge; Zhao, Yawen; Zou, Dongli; He, Lifeng

    2016-09-01

    Deformation twins in cast uranium strained to 4.2% and 6.2% by quasi static compression were investigated using electron backscattered diffraction and transmission electron microscopy. Twin types of {130}, '{172}', {112} and '{176}' were observed in present experiment. All the operative twin variants in each twin type have the highest Schmid factor among the equivalent variants. Some {130} twins in cast uranium were inclined to disappear during subsequent loading through the re-twinning processes with Schmid factor values greater than 0.4. The '(-176)' variant was identified by indexing the electron diffraction pattern combining with the stereographic projection analysis. Twin pairs of '(-176)'-'(-17-2)' occurred in the adjacent grains were well matched with the geometric compatibility factor value of 0.933.

  18. A generalized Defries-Fulker regression framework for the analysis of twin data.

    Science.gov (United States)

    Lazzeroni, Laura C; Ray, Amrita

    2013-01-01

    Twin studies compare the similarity between monozygotic twins to that between dizygotic twins in order to investigate the relative contributions of latent genetic and environmental factors influencing a phenotype. Statistical methods for twin data include likelihood estimation and Defries-Fulker regression. We propose a new generalization of the Defries-Fulker model that fully incorporates the effects of observed covariates on both members of a twin pair and is robust to violations of the Normality assumption. A simulation study demonstrates that the method is competitive with likelihood analysis. The Defries-Fulker strategy yields new insight into the parameter space of the twin model and provides a novel, prediction-based interpretation of twin study results that unifies continuous and binary traits. Due to the simplicity of its structure, extensions of the model have the potential to encompass generalized linear models, censored and truncated data; and gene by environment interactions.

  19. Twinning behavior of polycrystalline alpha-uranium under quasi static compression

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ping [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Xiao, Dawu [Insititute of Materials, China Academy of Engineering Physics (CAEP), Jiangyou 621907, Sichuan (China); Wang, Wenyuan [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Sang, Ge, E-mail: success0066@126.com [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Zhao, Yawen; Zou, Dongli; He, Lifeng [Insititute of Materials, China Academy of Engineering Physics (CAEP), Jiangyou 621907, Sichuan (China)

    2016-09-15

    Deformation twins in cast uranium strained to 4.2% and 6.2% by quasi static compression were investigated using electron backscattered diffraction and transmission electron microscopy. Twin types of {130}, ‘{172}’, {112} and ‘{176}’ were observed in present experiment. All the operative twin variants in each twin type have the highest Schmid factor among the equivalent variants. Some {130} twins in cast uranium were inclined to disappear during subsequent loading through the re-twinning processes with Schmid factor values greater than 0.4. The ‘(−176)’ variant was identified by indexing the electron diffraction pattern combining with the stereographic projection analysis. Twin pairs of ‘(−176)’–‘(−17−2)’ occurred in the adjacent grains were well matched with the geometric compatibility factor value of 0.933.

  20. 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...... in the womb. Studies in rodents have shown that female fetuses developing between males are masculinized in several anatomical, physiological and behavioral traits....